Perceptual Change Topics




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For more information on the following topics, please click on the appropriate word:

  • Presbyopia
  • Glaucoma
  • Retinitis Pigmentosa
  • Macular Degeneration
  • Diabetic Retinopathy
  • Retinal detachments
  • Cataracts
  • Visual perceptual losses due to post-retinal changes
  • Presbycusis
  • Otosclerosis
  • Tinnitus
  • Touch
  • Taste
  • Smell

  • Presbyopia

    by Melissa Youngman

    What causes presbyopia?

    Presbyopia is the natural hardening of the crystalline lens within the eye, which causes individuals to loose the ability to focus on close objects and perform close up projects. Presbyopia occurs in over 50% of the population in their forties (Sinanoglue, 1996) . In a "normal" eye the lens changes shape in order to focus on objects: the ciliary muscles contract and thicken the lens to bring the object into focus (Bartley & Belau, 1990). However, as a person ages the lens becomes harder and less elastic, making it more difficult to see nearby object clearly. This hardening process is a normal part of life, and it happens to everyone to some degree (Bartley & Belau).

    What are some sypmtoms?

  • close objects become blurred
  • headaches and tired eyes
  • print newspapers and books type begin to seem smaller

    Why do these symptoms occur?

    Thse symptoms occur because the lens of the eye is losing its elasticity with age, making it function like a fixed-focus camera (Brown,1989) . Things up close look dim and blurred, requiring the use of either different pairs of glasses or bifocals. Individuals that are already farsighted may notice the changes somewhat earlier and will need to have stronger corrective lenses made. Even individuals who are nearsighted can will experience the effects of presbyopia. Nearsighted individuals normally have to take off corrective lenses to read small print (Bartley & Belau, 1990) .

    What is being developed?

    Delori and Burns (1996) developed an optical technique for measuring the invivo absorption for the the human crystalline lens based on using the retina as a reflector for a double-pass measurement of lens density. Results from the Delori and Burns study showed a continuous increase in lens density with age, and a small significant acceleration at older ages. The study by Delori helps support a theory that lenses will have lost most of their ability to accommodate by age 65.

    What is the best treatment?

  • Bifocals
  • Corrective Classes
  • Contacts
  • Lens Implant
  • InstrastromalCorneal Ring

    Brief summary of treatments:

    Bifocals and other corrective glasses have been the best treatment for presbyopia in the past decades. Doctors suggest getting a new prescription every few years until age 65. After that the lens of the eye has lost most of its ability to accommodate, and prescription changes are less frequent (Bartley & Belau, 1990) . More recentlly researchers have developed other options for individuals with this visual impairment. A contact lens has been invented that focuses light with a graded refractive index. The lens has the power to bend light rays changes from the center to the edge (Wu,1996). Another treatment option for people with presbyopia is a lens implanted on the cornea that acts like a bifocal. A surgeon inserts a wafer-thin lens, 2 millimeters in diameter, in front of the natural lens to help it focus on close objects. For people with presbyopia the implanted lenses act like a pair of reading glasses (Lipkin, 1993) . Also, a intrastromal corneal ring (ICR) is also said to help vision for people with presbyopia (Voelker,1995) . This device was first tested on individuals in 1991. The ICR is implanted into the cornea's optic zone and centered over the pupil, producing a region with higher refractive power. The effect of the lens, combined with vision form the unmodified portion of the cornea, produces a bifocal effect. It takes the brain about six months to adjust, but after that it adapts, ignoring distant images when close-up items are viewed and vice versa (Voelker) .

    Precautions and preventions:

    Individuals can prevent many eye problems from occurring through simple preventive measures. Doctors suggest individuals to avoid frequent use of eye drops, and for females to avoid waterproof mascara that flakes. They also emphasize the importance of wearing UV-ultraviloet protective sunglasses outdoors year-round. Most important of all seek medical attention for any eye injury (Brown,1989) .

    Even though presbyopia is a naturally occurring function within the eye these preventative measures and treatments can help people have less strain on daily activities and their lives. With the right care and knowledge individuals can have a lifetime of good vision.

     

    References

    Brown N. (1989, February) . To your health: The sight of your life. Nations Business, 77 (2) , 55.

    Delori, F. C, & Burns, S. A. (1996) . Fundus reflectance and the measurement of crystalline lens density. Optical Society of America, 13 (2) , 215-225.

    Lipkin, R. (1993, September 11) . Focusing the soul's fuzzy window. Science News, 144 (11) , 172.

    Sinanoglue, E. (1996, January) . Reading specs now easy on the eyes in more ways than one. Money, 25 (1) , 126.

    Voelker, R. (1995) . New techniques to resculpt the cornea. The Journal of the American Medical Association, 274 (19) 1493-1494.

    Wu, C. (1996, September 7) . Contacts for aging baby boomers' eyes? Science News, 150 (1) , 159.

    Other References and Links

    Bartley, G. B., & Belau, P. G. (1990). Mayo Clinic Family Health Book. In D. E. Bruce, A. S., Atchison, D. A., & Bhoola, H. (1995) . Accomodation-convergence relationships and age. Investigative Ophthalmology & Visual Science, 36 (2) , 406-413.

    Larson & D. E. Swanson (Eds.) , Presbyopia (pp.743-744) . William Marvow & Co. Inc., NY: New York.

    Braus P. (1995) . Vision in an aging America. American Demographics, 17, 34-38.

    West, S. K., Beatriz, M., Rubin, G. S., Schein, K. B., Zeger, S., German, P. S., & Fried, L. P. (1997) . Function and visual impairment in a population-based study of older adults. Investigative Ophthalmology & Visual Science, 38 (1) , 72-81.

    http://www.vision3d.com/eyecare/"

    http://www.lasercenter. com/eyework.html


    Glaucoma: Can You See the Problem?

    By Aaron Aiza

    Glaucoma is a disease in which high intraocular pressure damages the optic nerve and causes vision loss. "This disease is the second largest cause for permanent blindness in the United States"(Staff, 1995). Vision is a rapidly occurring process that involves continuous interaction between the eye, the nervous system, and the brain. When someone looks at an object, what he really sees is the light reflected from the object. This reflected light passes through the lens and falls on the retina of the eye. The retina is a soft, transparent layer of nervous tissue made up of millions of light receptors. Here, the light induces nerve impulses that travel through the optic nerve to the brain and then over other nerves to muscles and glands. If any of these areas are damaged, vision is reduced.

    As listed below, there are many factors that increase the risk of developing glaucoma. African Americans, and individuals over 40, along with other personal factors which include extreme nearsightedness (Myopia) or farsightedness (Hyeropia), high blood pressure, and steroid use, run a higher risk of developing glaucoma.

    There are a variety of ways that glaucoma can be treated, anything from eye drops to pills. Yet Ackerman (1995) concludes that medical researchers are still searching for a cure free from side effects.

  • Myotics have a tendency to make the pupil smaller, therefore increasing the risk of cataracts and producing dim vision.

  • Epinephrine has such side effects as allergic reactions, blurred vision, headache, and increased heart rate.

  • The side effects produced from Alpha adrenergic agonist include red eyes, allergic reactions, and dry mouth.

  • Diamox carbonic ahydrase inhibitor tablets seem to have more severe side effects on some individuals. These include mental depression, kidney stones, tingling in the feet and hands, and anemia.

  • Marijuana has fewer side effects than most drugs, although some researchers believe that the use of marijuana is harmful to the lungs and may cause hormonal and reproductive problems.

  • Scalpel surgery used to be the most frequently used method, but during the past 25 years laser surgery has become the most common.

  • Another treatment is plasma pheresis, which occurs when the aberrant proteins are separated from the blood of the patient, and then returned to the circulatory system. (Ackerman, 1995) To find out more about GLAUCOMA.

    In order to prevent the onset of glaucoma, visit an ophthalmologist. Family physicians can screen one for glaucoma, but more than likely will often unknowingly overlook the disorder. "Of all the people diagnosed with glaucoma, 50 percent of the patients had no idea they were suffering from the disorder"(Coleman, 1995). On the horizon, diligence in diagnosing the subtle onset of glaucoma is the best protection.

    To inquire about glaucoma from a doctor's perspective click HERE.

    References:

  • Ackerman,S.J. (1995). Guarding against Glaucoma. FDA Consumer, Nov. v. 29 p. 17(5).

  • Coleman, Anne L. (1995, Dec.) Glaucoma screening: a golden opportunity. American Family Physician. v.52 p.2167. (3)

  • Staff. (1995, Oct.) Immune system may trigger Glaucoma. USA Today. p. 10. (1)

    Additional References:

  • Chestnutt, James C. & Senechal, Peter K. (1996, July 15) Primary care: can you see the problem? Patient Care. v30 p. 210. (2)

  • Grierson, Ian. (1996, June 29) Glaucoma and nitric oxide. The Lancet. v.347 p.1781.(2)

  • Rogers, Adam. (1997, Jan. 13) Seeing through the haze: can marijuana ever be good medicine? Newsweek. p. 60. (1)


    Retinitis Pigmentosa:

    A Heterogeneous Disease

    by Brenda Albertson

    Retintis Pigmentosa is a hereditary , degenerative, and dysfunctional disease that affects more than 1.5 million (Berson, 1996) people worldwide. RP destroys the rods and involves progressive visual field loss, pigment changes in the retina, and night blindness. The onset of RP occurs typically during the teenage years; between the ages of thirty and forty the patient becomes legally blind.

     


    SYMPTOMS

     

  • Nightblindness, a reduction in peripheral vision, and eventually progression to tunnel vision (Http:/www.vwpro.com/users/ffb/inherit.html).
  • Patients usually develops cataracts and total blindness or severe handicaps (Http://www.vwpro.com/users/ffb/symptoms/)


    INHERITANCE PATTERNS

     

    Autosomal Retinitis Pigmentosa (ARP)

  • ARP is the mildest form and accounts for 25% of all cases; an ARP patient has one RP and one normal gene (Shastry, 1994)
  • 30% of ARP cases have been linked to mutations in rhodopsin and peripherin/RDS (Maghtheh, Vithana, Jay, Evans, Moore, Bhattacharyas, & Inglehearn, (1996)

     


    X-Linked Retinitis Pigmentosa

  • X-linked RP is the severe form of RP, responsible for 10% of all RP cases, and is primarily prevalent in males
  • Onset is due to an RP gene on the x chromosome and the RP gene is not paired with a normal gene (http://www.newcomm.net/webpage/can_ride/retinit.htm)


    Isolated Cases of Retinitis Pigmentosa

  • Isolated cases accounts for 40% of RP patients and delineate autosomal recessive disease (Shastry, 1994)

     


    TREATMENT

    NO cure exists for RP patients as of yet, but there are three treatments under experimentation currently:

  • Retinal transplants are a major clinical process and are increasingly becoming a typical treatment for RP patients (Sahel, et. al, 1996)
  • Vitamin A supplements and antioxidant agents are also being given to RP patients in anticipation of treating the disease (Berson, 1996)


    PREVENTION

    Prevention is the key to helping RP patients preserve as much of the deteriorating vision as possible. That can be done by:

  • Wearing sunglasses to protect against ultraviolet light from entering the eye (http:/www.vwpro.com/users/ffb/inherit.html)
  • Genetic testing can be done to determine the risk of an individual having a child with RP

     


    References

    Berson, E. L. (1996). Retinitis Pigmentosa: Unfolding its Mystery. Proceedings of the National Academy of Sciences of the United States, 93, 4526-4529.

    Chalkley, T. (1982). Your Eyes. Springfield, IL: Charles C. Thomas, Publisher.

    Daiger, S. P., Sullivan, L. S. & Rodriguez, J. A. (1995). Correlation of phenotype in inherited retinal degeneration. Behavioral and Brain Science, 18(3), 452-468.

    Grunwald, J. E., Maguire, A. M., & Dupont, J. (1996). Retinal hemodynamics in retinitis pigmentosa. American Journal of Opthamology, 122 (4), 502-505.

    Maghtheh, M., Vithana, E., Jay, M., Evans, K., Moore, T., Bhattacharyas, S., & Inglehearn, C. F. (1996). Evidence for a major retinitis pigmentosa locus on 19qB.4 (RP11) and association with a unique bimodal expressivity phenotype. American Journal of Human Genetics, 59 (4), 864-871.

    Sahel, J. A., Hicks, D., Mohand-Said, S., Tran-Minh, D., Deudon-Combe, A., Silverman, M., & Dreyfus, H. (1996). Retinal grafts: biological problems and clinical stakes. Bulletin for the Academy of National Medicine, 180 (3), 633-640.

    Shastry, B. S. (1994). Retinitis pigmentosa and related disorders: phenotypes of rhodopsin and peripherin/ RDS mutations. American Journal of Medical Genetics, 52 (4), 467-474.

    Sher, N. A., Trobe, J. D., & Weingeist, T. A. (1995). New options for vision loss. Patient Care, 29 (14), 55-66.

    Retinitis Pigmentosa- the disease and its symptoms. Http://www.vwpro.com/users/ffb/symptoms/

    Additional Links
    http://www.newcomm.net/webpage/can_ride/retinit.htm.
    Http://www.vwpro.com/users/ffb/inherit.html.


    Age-related Macular Degeneration

    by Sydne Steinberg

    Age-related macular degeneration is a disease in which the macula becomes progressively damaged (Crabtree, Adler, & Snodderly, 1996). The macula consists of a small fovea, containing only cones, that is enveloped by a bigger parafovea, made up largely of rods (Curcio, Medeiros, & Millican, 1996). The parafovea is where age-related macular degeneration begins (Curcio et al., 1996). The primary symptom of this irreversible disease is blurred vision. As time goes on, easily damaged blood vessels may grow in the retina where they tend to leak, causing further damage to the macula. From this point on, victims experience an extreme loss in vision that includes a small blind spot in the center of their field of vision (Tuffs University Diet and Nutrition Letter, 1995). Age-related macular degeneration is the leading cause of visual impairment, occurring in 1.7 million people in America alone (Christen, Glynn, Manson, Ajani, & Buring, 1996). Laser photocoagulation is an option for a handful of patients, but this merely delays the inevitable vision loss (Christen et al., 1996).

    Functions of the macula (Seddon, Willett, & Hankinson, 1996)

    Current research in this area

    Studies have been conducted in the areas of diet and smoking.

    Diet:
    Research has shown that a diet high in cartenoids, a family of yellow, orange,and red pigments found in fruits and vegetables, can reduce the chance of advanced macular degeneration (Fackelmann, 1994). Two members of this family, lutein and zeaxinthin, have been targeted to protect the macula (Fackelmann, 1994). These two cartenoids form the yellow pigment found in the macula (Fackelmann, 1994). People with a diet rich in cartenoids have been found to have a 43% reduced risk of advanced macular degeneration than those whose diet consists of few carteoids (Fackelmann, 1994).

    Smoking:
    The results from a study of cigarette smoking and risk of AMD in Men show that:

  • Current smokers of one pack of cigarettes or more a day had a two to three fold increased risk of AMD with vision loss compared to those who had never smoked.
  • Current smokers of less than one pack a day had no significant increase in risk of AMD.
  • Former smokers of one pack or more a day continued to have 40-80% excess risk of AMD with vision loss for many years following smoking cessation.
  • The results from A Prospective Study of Cigarette Smoking and Risk of AMD in women show that current and past smokers had a significantly higher risk of AMD when compared to those who had never smoked. Among the current smokers, the risk was increasingly high for those who smoked more than a pack a day.

    References

    Christen, W. G., Glynn, R. J., Manson, J. E., Ajani, U. A., & Buring, J. E. (1996, October). A prospective study of cigarette smoking and risk of age-related macular degeneration in men. JAMA, pp. 1147-1151.

    Crabtree, D. V., Adler, A. J., & Snodderly, D. M. (1996, January). Radial distribution of tocopherols in rhesus monkey retina and retinal pigment epithelium-choroid. Investigative Opthalmology & Visual Science, pp.61-74.

    Curcio, C. A., Medeiros, N. E., & Millican, C. L. (1996, June). Photoreceptor loss in age-related macular degeneration. Investigative Opthalmology & Visual Science, pp. 1236-1247.

    Fackelmann, K. A. (1994, November). Nutrients may prevent blinding disease. Science News, p.310.

    Seddon, J. M., Willett, W. C., Speizer, F. E., & Hankinson, S. E. (1996, October). A prospective study in cigarette smoking and risk of age-related macular degeneration in women. JAMA, pp.1141-1146.

    Sighted: foods for better vision. (1995, January). Tuffs University Diet and Nutrition Letter, p.1.

    You can link to these other sites for additional information on the topic of age- related macular degeneration!

    http.//www.eyenet.cug/public/faqs/macular_faq.html

    http.//www.web-xpress.com/vhsc/macdeg.html


    Diabetic Retinopathy

    By Kelly Taylor

    WHAT IS IT?

  • An eye disease associated with diabetes in which there is damage to blood vessels in the retina.
  • Blood vessels may swell and leak fluid or abnormal new blood vessels could grow on the surface of the retina.
  • Diabetic retinopathy is the number one cause of eye diseases in people between the ages of 20-74 and the leading cause of blindness in American adults (Internet 1).

     

    WHO IS AT RISK?

  • Anyone with diabetes is at risk for diabetic retinopathy (Internet 2).
  • The longer someone has diabetes the greater the risk for developing diabetic retinopathy (Internet 2).
  • Young, pregnant diabetic women are at great risk (Internet 1).
  • According to Smith (1996), African Americans are the most prevalent population with diabetic retinopathy (2/3 of population with d.r.)
  • Patients with elevated blood sugar levels and high blood pressure are also at risk (Internet 2 ).

     

    SYMPTOMS & PREVENTION

  • There are rarely symptoms in the early stages including no loss of vision and no pain (Dowdell).
  • The best most effective prevention is early detection and yearly checkups (Dowdell, 1995).
  • Presence of protein spillage in the urine is another hazard (Internet 2).
  • Control of blood sugar levels also slows the process of this type of vision loss (Internet 2).
  • A special diet is also sometimes prescribed to control blood sugar levels (Scheiner, 1994).

     

    TREATMENT

  • The most common treatment is laser surgery.
  • The laser beams are aimed into the retina and either seal the leaking blood vessel or shrink abnormal blood vessels (Bass, 1996).

     

    RESEARCH

  • The National Eye Institute along with other eye care centers around the nation are conducting studies which demonstrate preservation of vision (Internet 1).


    REFERENCES:

    Dowdell,H.R (1995). Diabetes and Vascular disease: A common association. AACN Clinical Issues,6(4),526-535.

    Smith, S.S. (1996). Keeping good vision with diabetic retinopathy. ABNF Journal, 7(3),81-84.

    Bass, S.J. (1996). Laser treatment of macular disease. Optometry Clinics,5 (1), 161-173.

    Scheiner, G. (1994). Exercise options for people with diabetic eye complications. Journal of Othalmic Nursing and Technology,13(6),267-269.

    Internet one (February 1997): http://niddk.nih.gov/Diabetic Eyedisease.html#four

    Internet two (February 1997): http://pw1.netcom.com/~macula/Southeast Retina.html

    For further references, please click below.

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    family


    Retinal Detachment

    By Lynae Carr

     

    Retinal detachment occurs when there is a separation of the retina, a thin sheet of light sensitive nerve tissue lining the inside of the eye, from the back wall of the eye. Retinal detachment commonly occurs in those over 50, those with diabetes, those who have a family history of retinal detachment, and those with horseshoe tears. Other risk factors include trauma, history of retinal detachment in the other eye, severe myopia, and aphakia and pseudophakia (Gaston & Elkington, 1986; Saran & Brucker, 1995; Stein, Slatt, & Stein, 1992; Eye-Online, 1997; Kim & Lowenstein, 1997) .

    Most retinal detachments are due to retinal tears or breaks in which liquid from the vitreous passes through the tear or break causing the retina to detach. As more fluid from the vitreous flows behind the retina through the hole, more of the retina becomes detached. Retinal detachment can also occur without holes or breaks in conditions in which fluid is secreted by either the retina or the choroid. If retinal tears and breaks are not detected and treated promptly, retinal detachment is likely to occur due to vitreous traction (Gaston & Elkington, 1986; Saran & Brucker, 1995; Stein, Slatt, & Stein, 1992; Eye-Online, 1997; Kim & Lowenstein, 1997).

    The symptoms associated with a retinal tear are black floaters and lightning-like flashes. As the detachment progresses, more of the area of the field of sight becomes blurred and it is more likely the detached areas of the retina will lose their vision. Sudden loss of sight might occur due to bleeding into the eye from the retinal tear. Gradual loss of sight can occur as a darkening of part of the field of sight; the darkening gradually enlarges until it causes the eye to become totally blind. Symptoms can also be absent in the case of retinal detachment and the person is only aware of a problem when a shadow appears on one or the other side of the eye (Gaston & Elkington, 1986; Saran & Brucker, 1995; Stein, Slatt, & Stein, 1992; Eye-Online, 1997; Kim & Lowenstein, 1997).

    There are several methods for surgical management of retinal detachment (Saran & Brucker, 1995; Eye-Online, 1996; Kim & Lowenstein, 1996). The goal of surgery is to reattach the retina and/or seal the hole or tear. Vitrectomy is a surgical procedure in which the vitreous gel is removed, thus eliminating the vitreous traction. Pneumatic Retinopexy is the process in which a gas bubble is injected into the eye to seal the hole and the gas pushes the retina against the eye wall, reattaching the retina in selected cases. Scleral buckling involves draining the fluid out from under the retina by making a small incision in the wall of the eye in the area of fluid. As the fluid is drained out, a scleral buckle, a flexible piece of rubber, is placed around the eye to support the retinal tear from outside the eye.

    Surgical success in terms of reattachment can be achieved in the large majority of cases. The return of sight, however, is gradual and depends on several other factors (Saran & Brucker, 1995). It has also been found that since the detachment may damage the retina, most people do not get back perfect vision (Kim & Lowenstein, 1996).

     

     

    REFERENCES

     

    Gaston, H. & Elkington, A. (1986). Opthamology for Nurses. New Hampshire: Croom Helm Ltd.

    Saran, B.R. & Brucker, A.J. (1995). Macular Epiretinal Membrane Formation and Treated Retinal Breaks. American Journal of Opthamology, 120, 480-484.

    Stein, H.A., Slatt, B.J., and Stein, R.M. (1992). A Primer in Opthamology. Missouri: Mosby-Year Book, Inc.

    Recent Advances in Retinal Detachment Surgery (Feb. 1997) Eye-Online http://www.usa.net/eol/retinal/recent advances in retinal detachment surgery.html

    Retinal Detachment (Feb. 1997) Rosa Y. Kim, M.D. and John I. Lowenstein M. D. http://netope.harvard.edu/meei/PI/RD.html

     

     

    ADDITIONAL REFERENCES AND LINKS

     

    Chechelnitsky, M., Mannis, M.J., & Chu, T.G. (1995). Scleromalacia After Retinal Detachment Surgery. American Journal of Opthamology, 119, 803-804.

    Yasukawa, T., Fukuda, T., Kishimoto, M. & Ogura, Y.J. (1995). Prediction of Postoperative Visual Acuity in Retinal Detachment with Macular Involvement. American Journal of Opthamology, 120, 276.

    http://www.geocities.com/HotSprings/2357/infloat.html

    http://www.eyeville.com/eyeret.html


    Cataracts

    by Sara Borek

    Human cataracts represent one of the major causes of treatable blindness. A cataract is a cloudy area in the lens of the eye. The lens is transparent and very important for focusing a sharp image on the retina (Goldstein, 1996). The human lens works a lot like a camera lens because it focuses light onto the retina at the back of the eye, where an image is then recorded. The lens is made up mostly of water and protein. As people age, the protein may clump together and start to cloud a small area of the lens. This is what's known as a cataract and it can potentially block out some of the light trying to get through . As a cataract develops, it becomes harder for a person to see, mainly because it could grow larger and cloud more of the lens (HTTP://WWW:NEI.NIH.GOV...).

    Cataracts occurs in 75 percent of people over 65 and 95 percent of people over 85. In a study by Klein, Wang, and Meuer(1995), it was found that age-related maculpathy (macular degeneration and geographic atrophy) and cataract are important causes of decreased vision as people grow older.

    The majority of the people who have cataracts have them bilaterally, or in both eyes. It is possible, though, that one eye may be worse than the other. This is mainly because each cataract develops at a different rate. A cataract can be so small that people may not even know it is there. Fortunately in only about 15 percent of the cases does the cataract interfere with a person's normal activities, and only about 5 percent of cataracts are serious enough to require surgery (Goldstein, 1996). The procedure for having a cataract removed involves making a small opening in the eye. The surgeon removes the lens while leaving in place the capsule, which is a structure that supports the lens. There are three types of suguries usually performed:

    1. Extracapsular: The eye surgeon removes the lens,leaving behind the back half of the capsule (the outer ocovering of the lens).

    2. Phacoemulsification: In this type of extracapsular surgery,the surgeon softens the lens with sound waves and removes it through a needle. The back half of the capsule is left behind.

    3. Intracapsular: The surgeon removes the entire lens,including the capsule. This method is rarely used (HTTP://WWW:NEI.NIH.GOV...)

    When the lens is removed, an intraocular lens is put in place of it. An intraocular lens is a plastic lens which is placed inside the eye, where the original lens used to be.

    References

    HTTP:// TEXT.NLM.NIH.GOV./AHCPR/CAT/WWW/CATPTXT.HTML

    HTTP://WWW:NEI.NIH.GOV/PUBLICATIONS/CATARACT.HTM

    Goldstein, E. B. (1996). Sensation and Perception. 4ed. Brooks/Cole Publishing. Klein, R., Wang,Q., Klein, B., Moss, S., & Meuer, S. (1995). The Relationship of Age-Related Maculopathy, Cataract, and Glaucoma to Visual Acuity. Investigative Ophthalmology & Visual Science, 36.

    For more information, look at cataract surgery and cataract.


    Visual Perceptual Losses Due to Post-Retinal Changes

    By Shandra L. Session

    There are a number of changes that occur within the human body as it ages. Specifically, a major effect of aging on the human body can be seen in in the brain. These modifications can affect an individual's perception, sometimes to a great extent; for example, changes in perception as a direct result of age-related dementia. Although dementia can be correlated with aging, it is not a certainty of old age. Some elderly adults are only slightly affected by age-related dementia, whereas other elderly individuals may not be affected at all. According to Meaney, O'Donnell, and Rowe (1995), although evidence for learning, memory, and language loss appears in some individuals as early as 50-55 years of age, many people continue to function alertly well into their 90's. Certain individuals may have a predisposition for dementia, for example, a genetic makeup, exposure to toxins, etc. Age-related dementia can also be a result of an underactive mind; areas of the brain that are not used may deteriorate over time. Thus, the elderly should be incouraged to participate in a variety of activities that increase neural activity.

    The potential genetic influence in dementia has been supported by the study of Alzheimer's (an extreme form of age-related dementia). Individuals whose parents developed Alzheimers have a greater chance of also developing Alzheimers. Physiological changes may include gradual neuronal death, a thinning of axons and myelin sheaths, a decrease in the number of receptors, and neurofibrillary tangles and senile plaques (Boss,1991).

    A general slowing of response time is another effect of aging; however, a study done by Stanley and Richard (1993) showed that this slowing in reaction time can be slowed with repetition of a specific task. Further, appropriate training can:

    In general,

  • Maintain and improve range of motion, strength, flexibility, balance, and endurance

  • Reduce the disability of the cardiovascular, respiratory, and musculoskeletal systems that may result in decreased risk of falls and accidents.

  • Counterbalance age-associated declines in work capacity and physical performance.

    The slowing of response time with aging directly interacts with visual perception in activities such as driving. The time it takes for an elderly person to perceive a potentially hazardous condition on the highway and react to it is longer than that of a younger person.

    For more information on aging,click here!

    For more information on Alzheimers's,click here!

    For more information on dementia, click here!

    References:

    Boss,B.J. (1991). Normal aging in the nervous system: implications for SCI nurses Aging-Physiology,8, 42-47.

    Meaney, M.J., O'Donnell, D., & Rowe, W. (1995), Individual differences in hypothalamus-pituitary-adrenal activity in later life and hippocampal aging. Developmental Neuroendocrenology,30, 229-251.

    Stanley, M. & Richard, R. (1993). Treatment considerations for the elderly. Occupational and Physical Therapy, 15, 559-565.


    Presbycusis

    by Ella L. Bowser

    As the body ages, many changes take place. The body has a natural tendency to wear down. Over time the functions of the major systems of the body show a decline or cease to work altogether. One may not realize his or her senses are fading. Senses like vision and hearing often deteriorate gradually. Presbyopia (hardening of the lenses of the eye) and Presbycusis (loss of the ability to hear high frequencies) are diseases that are age related.

    Presbycusis accounts for about 16% of all hearing loss (Magno, 1991). A sensorineural hearing loss occurs when there is damage to the inner ear. Researchers once assoicated presbycusis with tinnitus (ringing of the ears) and vertigo (dizziness) (Carmen, 1977). However, current research indicates tinnitus and vertigo to be associated with Meniere's syndrome (Magno, 1991). Presbycusis is a sensorineural hearing loss.

    There are certain risk factors associated with presbycusis: age (generally appears after age 40); gender (males are more likely to suffer from presbycusis than females); and line of work (expousre to workplace noise).

    Due to medical advances in the area of hearing, presbycusis can be treated using hearing aids to amplify sound. This form of treatment for presbycusis was not available 20 years ago. Goldstein (1996) also recommends treatment by teaching people more effective communitcations strategies.

    Many people might have a hard time admitting that there is something physically wrong with them. Instead, they may become depressed and withdraw from family and friends. This is one of the reasons that gerontology has become a prominent field in psychology. Advances in the body of knowledge of aging benefits all.


    References

    Carmen, R. (1977). Our endangered hearing: Understanding & coping with hearing loss. Rodel Press, Emmaus, PA. 50-52.

    Humes, L. E. , Halling, D., & Coughlin, M. (1996). Reliability and stability of various hearing-aid outcome measures in a group of elderly hearing-aid wearers. Journal of Speech and Hearing, 39, 923-935.

    Goldstein, E. B. (1996). Sensation and Perception. 4ed. Brooks/Cole Publishing.

    Mango, K. (1991). Hearing loss. Franklin Watts. New York.

    Porell, W. (1986). Lifespan plus. Macmillan Publishing Company. New York.


    Otosclerosis

    By Shelly Kruk

    Hearing loss affects nearly half of the population of people more than 65 years of age. Otosclerosis is one of the causes of hearing loss and affects 10% of the population. This condition is an inherited disorder involving the growth of abnormal spongy bone in the middle ear. The growth prevents the stapes from vibrating in response to sound waves which leads to a progressive conductive hearing loss. This is the most frequent cause of middle ear hearing loss in young adults and is most commonly seen in women ages 15 to 30. Risks of developing otosclerosis include a family history of hearing loss and pregnancy may trigger its onset. Caucasians are also more susceptible to otosclerosis than any other races (www.housecall.c...mi/97).

    There are very few symptoms of otosclerosis which include:

  • slow progressive hearing loss
  • ability to hear better in noisy environments rather than quiet areas
  • ringing in the ears
  • To distinguish otosclerosis from other causes of hearing loss a head CT scan or head x-ray may be used (www.housecall.c...mi/97), and an audiometry/audiology may determine the extent of hearing loss. .

    Otosclerosis progresses slowly so the condition may not require treatment until the extent of hearing loss is significant. There is no local treatment to the ear itself or any medication that will improve the hearing in patients who have otosclerosis. Stapes surgery is the recommended treatment for patients with otosclerosis (www.voice-center.com/97). This surgery removes the stapes and replaces it with a prothesis. With state-of-the-art surgical techniques, about 90% of current patients can expect significant improvement (Gantz,B.,Schindler,R.,Snow,J., 77-78). However, the surgery can cause complications like infections, dizziness, pain, and blood clots in the ear. These complications usually correct themselves within a few weeks. Maximum hearing is usually obtained in approximately 4 months (www.housecall.c...mi/97).


    REFERENCES:

    http://www.housecall.c.mi/convert/001036.html

    http://www.voice-center.com/otosclerosis.html

    Cole, J.M., Giddings, N.A., Millman, B. (1996). "Long-term follow-up of stapedectomy in children and adulescents." Otolaryngol-Head-Neck-Surgery:78-81. Gantz, B.J., Schindler, R.A., Snow, J.B. (September 1995). ÒAdult hearing loss:some
    tips and pearls.Ó Patient Care:77-78.

    Murphy, T.P., Wallis, D.L. (1996). "Stapedectomy in the pediactric patient." Laryngoscope: 1415-1418. Vartianiner, E. (1995). "Surgery in elderly patients with otosclerosis." Department of Otolarynegology: 536-538.


    ADDITIONAL REFERENCES AND LINKS:

    http://www.boystown.org/hhirr/otoscler.html

    http://www.earsurgery.org/otoscl.html

     


    Geriatric Tinnitus

    by Shannon Hightower

    Tinnitus is most often characterized by the perception of ringing or buzzing in the ears or head, but different forms of sounds such as roaring, hissing, clicking and even crickets chirping have been described by sufferers. This sensation is mistakenly generated within the auditory system itself or by a vibration produced in the surrounding tissues or bones of the head; there is no corresponding sound in the external environment (Slayter & Terry, 1987). While individuals of all ages may experience tinnitus, its prevalence increases with age. Because it is often a symptom of normal hearing loss, tinnitus primarily affects people over the age of 50 (Fiscus, 1995). According to research by Ross, Echevarria, & Robinson (1991), tinnitus is one of ten chronic conditions reported most by those over the age of 65. Most cases of tinnitus among the elderly are attributed to the irreversible degeneration of the auditory system with age, a disorder known as presbycusis. "The prevalence of tinnitus matches that of presbycusis in the population from 40 to 60 years of age" (Fitzgerald, 1985, p. 230).

    Tinnitus is divided into two subgroups: objective tinnitus and subjective tinnitus. Objective tinnitus is rarely diagnosed; it is present in only one percent of individuals complaining of tinnitus. In this type, noises are caused by abnormalities within the arteries of the head and neck or is due to a problem in the system of veins at the base of the skull. With subjective tinnitus, hearing loss accompanies the noise, usually indicating damage to the auditory system. Damage could result from a number of things, including Menieres Disease, long term exposure to loud noises, impacted wax in the external canal of the ear, a tear in the tympanic membrane, and the degenerative effects of aging. Because of the seriousness of the abnormalities associated with objective tinnitus, it is extremely important for individuals experiencing tinnitus to report their symptoms to an otorhinolaryngologist, a physician specializing in ear, nose and throat disorders, who can complete a thorough medical examination to determine whether the tinnitus is objective or subjective.

    Although no cure for tinnitus has been found, objective tinnitus can often be alleviated through medication or surgical intervention to eliminate the existing pathology. When auditory damage is found to be the cause of tinnitus, a variety of treatments offer partially effective alternatives to the ringing sensation and other problems frequently associated with tinnitus. Hearing aids, which merely amplifies external sounds, and maskers, which provide an alternate, less annoying white noise, have been shown to reduce tinnitus in some clients. Drug treatment with Lidocaine has had mixed results for tinnitus. Antidepressant and antianxiety medications is often used in conjunction with psychological techniques to reduce the secondary symptoms of depression and anxiety caused by tinnitus. Psychological treatments offer the most help in chronic tinnitus sufferers. Biofeedback, relaxation techniques, and counseling directed at the reduction of stress rather than reducing the noticeability of the symptoms, seem to help improve coping strategies and stress management. Alternative treatments, including hypnosis, acupuncture, and yoga, are controversial and supported by little research.

    Many elderly sufferers are intolerant of their tinnitus and report high levels of stress compounded by other health problems and by their loss of social support. Since most elderly are retired, they may have little else to do with their time but listen to the noise (Ross et al., 1991). Although in the majority of cases, serious medical conditions are ruled out during the initial physical examination, the elderly often worry that their tinnitus is a sign of impending stroke, brain tumor, or insanity. Even though most elderly sufferers benefit from education, reassurance, and one or more of the traditional treatment methods, persistent tinnitus can compromise the elderly patient's sense of well-being, leading to a lower quality of life (Ciocon, Amede, Lechtenberg, & Astor, 1995).

    References


    Ciocon, J., Amede, F., Lechtenberg, C., & Astor, F. (1995). Tinnitus: A Stepwise Workup to Quiet the Noise Within. Geriatrics, 50(2), 18-25.

    Fiscus, J. (1995). New Hope for Ringing Ears. American Health: Fitness of Body and Mind, 14(10), 8-9.

    Fitzgerald, D. (1985). The Aging Ear. American Family Physician, 31(2), 225-232.

    Ross, V., Echevarria, K., & Robinson, B. (1991). Geriatric Tinnitus: Causes, Clinical Treatment, and Prevention. Journal of Gerontological Nursing, 17(10), 6-11.

    Slater, R., & Terry, M., (1987). Tinnitus: A Guide for Sufferers and Professionals. London, UK: Croom Helm.

    Additional References and Links


    Alster, J., Shemesh, Z., Ornan, M., & Attias, J. (1993). Sleep Disturbance Associated with Chronic Tinnitus. Biological Psychiatry, 34, 84-90.

    O'Conner, C., & Zappia, J. (1993). Management of the Tinnitus Patient. Journal of the Academy of Rehabilitative Audiology, 26, 25-38.

    Stouffer, J., & Tyler, R. (1990). Characterization of Tinnitus By Tinnitus Patients. Journal of Speech and Hearing Disorders, 55, 439-453.

    Wilson, P., Henry, J., Bowen, M. & Haralambous, G. (1991). Tinnitus Reaction Questionnaire: Psychometric Properties of a Measure of Distress Associated with Tinnitus. Journal of Speech and Hearing Research, 34, 197-201.

    Click here for additional information on Subjective Tinnitus.

    Check out the Tinnitus FAQ page.



    Touch

    by Anna Martin

    Our sense organs are faculties by which outside information is received for a response and perceptual. One of our great senses is touch. Many of us don't pay much attention to our ability to touch and feel things. Touch is a sense by which the body perceives contact with a substance. This is accomplished by nerve endings in the skin that convey sensations to the brain by way of nerve fibers. When we age, we tend to lose the sensitivity to many of the pressures from touching.

    We touch things everyday. We touch to show gesture such as a caring pat, a hug, or even a handshake. These all relay a message to the receiver. Active touch is when we physically explore an object by moving our fingers over it's surface.

    Touch is affected by age. In advancing age, our corpuscles in our fingers become less organized and show degenerative changes (Selmanowitz, 1977). Such dementia can result in accidents. Light touches are not detected. An elderly person may not feel their loved one patting or holding their hand, and this could leave the elderly person feeling unloved. The elderly person may also not feel slight bumps into objects, which could lead to bruising. Bozian (1980), lists measures that should be taken to help people suffering from such a loss:

  • reach out and touch the elderly when they are spoken to
  • teach them to purchase loose clothing (tight clothing could interfere with breathing and circulation
  • keep up with food oral hygiene
  • make sure the bed linens have no wrinkles (this might interfere with circulation)
  • regularly maintain wheelchairs and furniture
  • yearly eye exams (may not notice foreign objects in the eye)

    A factor that affects the elderly is stress-induced analgesia, which is a lower level of sensitivity to pain that occurs in stressful positions. This is detrimental because one does not feel pain due to being under pressure. Another problem associated with touch is the inability to feel deep pressure. This could lead to difficulties in everyday life. The best medicine for such problems is regular exercise (Bozian, 1980).

    In a study on electrical stimulation of pain and touch, Gibson (1968), found that direct electrical stimulation of the skin will wake up touch sensations similar to those of vibration or brief contact. In order to learn and study the influences of pain we must first know the properties of touch.

    References:
    Bozian, M. W. (1980). "Counteracting sensory changes in the aging." American Journal of Nursing, pp. 473-476
    Gibson, R. H. (1968). "Electrical stimulation of pain and touch." The Skin Senses, pp. 223-256.
    Selmanowitz, V. J. (1977). "Aging of the skin and itÕs appendages." The Biology of Aging, pp 496-499.

    Other references:
    Goldstein, B. E. (1996). Sensation and Perception, 4th ed. Brooks/Cole Publishing: New York.
    Department of Public Health and Primary Health Care (February, 1997).
    The Physiology of Perception (February, 1997).


    Taste

    by: Shannon Van Buskirk

  • About two to four million Americans suffer from a taste or smell disorder, and either of these disorders can affect a person's sense of taste. A sense of taste helps a person to detect and identify stimuli in the environment and is important for regulating the intake of foods and beverages. Taste is a sensation that occurs in the taste buds and allows us to perceive various flavors of different foods and beverages. A taste disorder is diminished, altered, or a complete loss of taste sensation. Hypogeusia is reduced taste function, dygeusia is the distortion of taste function, and ageusia is the complete loss of taste. The average adult has 10,000 taste buds, located on the tongue, which distinguish between four basic flavors: sweet, sour, salty, and bitter. The number of taste buds decline with age, causing a slight decrease in sensation. However, the loss is so minimal that it is usually not noticeable until after age 70. A decrease in taste may affect the enjoyment of food and, possibly, lead to nutritional deficiencies. The decline in taste sensation may not be caused by age but, rather, environmental factors. Such factors that contribute to the loss of taste are nutritional deficiencies, poor oral hygiene, smoking, dentures, or abuse to the taste buds from repeated scalding of the tongue with hot foods or beverages (Mold,1995).
  • If no environmental factors cause impairment, then the ability to taste bitter, sweet, sour, and salty foods should be fine through age. In fact, most age-related problems with taste may be due to smell disorders. Dr. Robert Henkin (1994) found that 90% of the cases of taste dysfunction in patients can be attributed to impaired olfactory reception function. An older person may think that he or she has lost the sense of taste , but it is most likely to be a loss of smell that he or she is experiencing. A zinc-deficiency is thought to be an underlying factor of the smell and taste disorders. However, treatment for the disorders are difficult because little is known about these problems. On the positive side, because taste receptor cells which are located in the taste buds are constantly regenerating themselves throughout life, there could be a way to replace these and other damaged sensory and nerve cells.
  • Taste sensory loss is very mild with age and may not be evident unless some physiological damage is done to the olfactory or taste functioning, either by environment or pathological factors. Therefore age may not be responsible for any taste loss, however, age simply provides a greater amount of time in which to encounter these problems.
  • References

    Mold, James, "Sensory Loss can be Averted," USA Today, February 1995, Vol. 123, No. 2597, pp.8.

    (1996)http://www.healthtouch.com.

    Henkin, Robert I., "Loss of Taste or Smell: a Rational Approach," Patient Care, September 1994, Vol. 28, No.15, pp.40.

    Additional References and Links

    Duffy, Valerie, "Making Sense of Taste and Smell," Tufts University Diet and Nutrition Letter, Nov. 1995, Vol.13, No. 9, pp.3.

    (December 1996)http://www.vetmed.com.

    Mott, April, "Disorders in Taste and Smell," Medical Clinics of North America , Vol.75, pp.1321-1353.

    Http://www.geron.uga.edu/~rob/Phys.taste.html.

    Http://www.csa.com/crw/prehome.html/.

     


    Smell

    By Shannon Street

    The sense of smell is a necessary commodity to the human species in order to promote survival and enjoyment of life. Humans unconsciously use smell for many things such as sensing danger, familiarity of loved ones, and the earth after a rainstorm. Humans consciously associate smell with flowers, dinner time and the cleanliness of clothing. Smell is defined as "one of the five senses of the body by which a substance is perceived through the chemical stimulation of olfactory nerves in the nasal cavity by particles given off by that substance" (Websters). Smell is a very complex but amazing process that intensifies as we age up to late adulthood then decreases to a level below that with which we were born.

    The smelling process is not the same for all people. Every human, whether it be a child, woman, or man, has their own perception of smell. Children before the age of five do not believe that anything smells bad. By the age of ten, both boys and girls begin having likes and dislikes towards odors. Women identify odors better than men. They use smell for cooking, smelling foods for freshness, perfumes and bonding to their newborns. Men are aroused by odors and depending on the pleasantness or unpleasantness of the experience, will determine if the odor was good or bad. As men and women get older, the smell intensity begins to diminish. Research by Chalke, Dewhurst & Ward (1982), found that older people were less sensitive to odors than younger people. Wysocki & Pelchat (1987), also found that there was a decline of odor perception with age.

    Age is not the only factor involved with the declined sense of smell. Many illnesses and diseases directly affect smell. For example, allergies, nutrient deficiency, obesity, strokes, tumors and AlzheimerÕs. Some people are born with smell loss, but the majority of cases are due to illnesses and diseases. Therefore, smell is a delicate sense that needs to be handled with care.

    In conclusion, this sense is not currently a research priority therefore society tends to take the smell issue for granted due to the fact that people are not consciously aware of the fragility of their sense of smell. However, people need to become knowledgeable of their sense of smell due to how many things influence the loss of smell.

    References

    Chalke, Dewhurst & Ward (1982). Anosmia In Engen, T.The Perception of Odor. New York: Academic Press. New York: Acadenic Press (pp. 90-91).

    Wysocki, C. & Pelchat, M. (1987). The Effects of Aging on the Human Sense of Smell and Its Relationship to Food Choice. Journal of Critical Reviews in Food Science and Nutrition, 33, 63-82.

    Additional References and Links

    Gibbons, B. (1986). The Intimate Sense of Smell/National Geographic Smell Survey. National Geographic, 170, 324-361.

    Goldstein, B. (1996). Sensation & Perception. Pacific Grove: Brooks/Cole Publishing Company. 504.

    Internet. (Feb.1997). Because You Asked About Smell and Taste Disorders. http://www.nih.gov/nided/smltaste.htm.

    Internet. (Feb.1997) Taste and Smell. http://www.nutramed.com/zeno/smell.htm.

    Winter, R. (1976). The Smell Book. Philadelphia: J.B. Lippincott Company. 142-146.

    http://www.nih.gov/nidcd/smltaste.htm.
    http://www.nutramed.com/zeno.smell.htm.
    http://www.csa.com/crw/prehome.html
    http://caps.otago.ac.nz:801/FOSC/SENSORY/HOME.html


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