The Aging Eye and Glaucoma
Chat Highlights
March 31, 2004

Norma Devine, Editor

On Wednesday, March 31, 2004, Dr. Elliot Werner, a glaucoma specialist at Wills, and the glaucoma chat group discussed "The Aging Eye and Glaucoma."

Moderator:  Hello, Dr. Werner.  Welcome back.

Moderator:  Tonight's topic is "The Aging Eye and Glaucoma."  Dr. Werner, what happens to our eyes as we age?  

Dr. Elliot Werner:  There are several well-recognized aging changes in the eye.  First, tear production decreases, so the eyes become drier and more easily irritated.  Second, the lens of the eye becomes larger, more dense, and more pigmented.  If these changes become profound enough to interfere with vision, it is called a cataract.

P:  Can a cataract cause increased IOP (intraocular pressure)?

Dr. Elliot Werner:  In rare circumstances, the cataractous lens of the eye can become large enough to push the iris forward and cause closed-angle glaucoma.  Extremely advanced cataracts, where the lens is completely white or mature, can cause severe eye inflammation that can lead to glaucoma. The usual early-to-moderate cataract does not cause glaucoma.

P:  Do most people get cataracts if they live long enough?

Dr. Elliot Werner:  Yes, most everyone gets cataracts, but not everyone is significantly visually impaired by cataracts to the point that surgery would be indicated.

P:  Is it better to remove a cataract at an early stage rather than a late stage?

Dr. Elliot Werner:  Cataracts should be removed when they interfere with vision to the extent that the activates of the patient are limited.  All surgery carries with it some risk.  Cataract surgery is generally quite safe as surgery goes, but imagine how a patient would feel if an asymptomatic cataract was removed and the patient got a severe infection or hemorrhage and completely lost the sight of that eye.

P:  How about floaters, those annoying "cobwebs" or "worms" that move when you try to focus on them?

Dr. Elliot Werner:  As we age, the vitreous (the jelly-like fluid in the eye) becomes more liquid and develops opacities and debris, so the number of floaters increases.  Retinal and optic nerve cells die off at a fairly steady rate, so visual function decreases somewhat with age, even in the absence of serious eye disease.  These are all physiologic changes that happen to everybody.  There are also certain diseases, such as macular degeneration and glaucoma, that are more common in older people. 

P:  In the normal eye, at what age does the vitreous tend to break lose from its surrounding tissue? 

Dr. Elliot Werner:  This varies a lot.  In nearsighted (myopic) people we often see this in middle age, 40's or 50's, but it can occur at any age.  Most people by the age of 70 have a vitreous detachment.

P:  Can anything be done to dissolve floaters or minimize their occurrence?

Dr. Elliot Werner:  Probably not for most types of floaters.  In severe cases, vitrectomy can be done, but this is rather drastic and risky for most benign floaters.

P:  Does the incidence of glaucoma increase with age? 

Dr. Elliot Werner:  Yes, probably, because older eyes are more susceptible to damage, and because the eye pressure tends to increase with age.

P:  Does the eye stop changing or change at a slower rate at some time in life?  

Dr. Elliot Werner:  That depends on which function you look at.  Optic nerve fibers are lost at a fairly constant rate throughout life. Presbyopia develops at about age 45 and progresses generally to about age 60 or so, then stops.

P:  Dr. Werner, what is presbyopia?

Dr. Elliot Werner:  Presbyopia is the loss of focusing power of the lens with age, so you become progressively less able to focus on near objects.  That is why those of us over age 45 or so need reading glasses or bifocals to compensate for the loss of the eye's focusing ability.

P:  Do most people get glaucoma if they live long enough?

Dr. Elliot Werner:  No, most studies have shown that even in very old persons, the prevalence of glaucoma ranges between 5 and 25% -- still below half the population.

P:  Is the aging eye more or less prone to healing?  

Dr. Elliot Werner:  Healing, like most functions, deteriorates with age.  We all know how quickly children heal and how long an older person can take to recover from surgery, injuries, or illness.  The immune system also deteriorates with age, so resistance to disease lessens.

P:  Do we need more light as we age?

Dr. Elliot Werner:  Most older people need more light to read or see well because of the physiologic and pathologic changes in the eye and vision that tend to accumulate with age.  I'm 57-years old and I know I need more light to read than my 22-year-old daughter.

P:  Does aging cause glaucoma to become worse?  

Dr. Elliot Werner:  The duration of glaucoma seems to increase the risk of damage.  Since glaucoma is a long-term, chronic disease, if you have glaucoma for 20 years, you are 20 years older, so it is difficult to separate the effects of age from the effects of the long duration of the disease.

P:  Is blue-on-yellow (B/Y) perimetry effective for the ageing lens?

Dr. Elliot Werner:  Interesting question.  Early lens changes do not seem to have much effect on B/Y perimetry.  More advanced cataracts may affect it more profoundly than does white-light perimetry.

P:  Is there a known correlation between arcus senilis (corneal senilis) and normal-tension glaucoma in the elderly?

Dr. Elliot Werner:  Not that I know of.  Arcus is associated with high cholesterol and an increased risk of heart disease, especially when seen in younger (middle-aged) patients.

P:  In the elderly, is arcus senilis (1) "a degenerative corneal disease," (2) "a totally benign accumulation of lipids," or (3) "a sign of cerebral anemia?"  (The literature can't seem to make up its mind.)

Dr. Elliot Werner:  I don't know, but we see tons of patients with arcus who seem otherwise normal and healthy.

P:  My 92-year old aunt has very poor vision in one of her eyes.   Other than that, she enjoys good health.  She said she was told nothing can be done about her bad vision. 

Dr. Elliot Werner:  I don't like that answer.  If someone has "very poor vision," there should be an explanation, such as macular degeneration, optic atrophy, cataract, etc.  Even in the 90's, an otherwise normal eye should have at least 20/40 vision.

P:  Is there an age when you would not recommend surgical intervention?

Dr. Elliot Werner:  Age is less a factor than general health. An otherwise fit 100-year-old person can easily go through cataract surgery, whereas a very sick 60-year-old person might not be a good surgical candidate.  In glaucoma surgery, the recovery takes longer and the risks are greater than for cataract surgery.  Therefore, the patient's potential lifespan plays a more important role in glaucoma surgery than in cataract surgery.

P:  If you have the start of cataracts, should you avoid using  antihistamines and decongestants?

Dr. Elliot Werner:  I don't know of any evidence associating cold or allergy meds with cataracts.  Probably makes no difference.

P:  Do you ever have to tell elderly people they cannot drive anymore?   When is such a determination made?  

Dr. Elliot Werner:  Every state has laws defining the vision needed to drive.  In Pennsylvania, you must have 20/40 vision or better in at least one eye, and at least 120 degrees of visual field with both eyes open.  If you don't meet those requirements, you can't legally drive.  Doctors are legally required to notify the state of any patient not medically fit to drive.

P:  I was extremely nearsighted until my late 40's.  Then my distance vision began to improve spontaneously.  It continues to do so, though I have developed minor presbyopia.  My mother had a similar improvement in eyesight, until her distance vision became 20/20. (She, however, never had presbyopia.)  We both developed normal-tension glaucoma (NTG).  Can you explain the improvement in distance vision, and would you suppose there might be a connection between that and normal-tension glaucoma? 

Dr. Elliot Werner:  I cannot explain the decrease in myopia, but the most common cause would be changes in the refractive power of the lens or cornea.  Normal-tension glaucoma, as well as open-angle glaucoma, are more common in myopic patients, but those glaucomas do not, themselves, seem to cause changes in refractive error of the eye.

P:  When the IOP rises in an eye, does the eye become more myopic?  

Dr. Elliot Werner:  Increasing myopia in response to increased IOP is thought to occur only in children and adolescents.  In older adults, it probably does not occur, or is fairly minimal. Progressive myopia in a child, however, can be a sign of glaucoma.

P:  Please explain the term "progressive myopia."

Dr. Elliot Werner:  Myopia that increases year after year between early childhood and age 20 or so.

P:  One year after my trabeculectomy,  I was surprised to learn that I had a cataract in the operated eye.  Could the trab have caused the cataract?  

Dr. Elliot Werner:  Yes, there is ample evidence that an increase in the risk of cataract and more rapid development of cataract occurs after trabeculectomy.  The reason is not well understood. Interestingly, treatment of glaucoma with drops is also associated with an increase in cataract.

Moderator:  That was the last question.  Thank you, Dr. Werner.

Dr. Elliot Werner:  You're welcome.   I hope everyone has a happy Passover and Easter season.

End of highlights for March 31, 2004.

On April 7, Dr. Wilson discussed "When Glaucoma Specialists Meet" in the Chat room. Click here for highlights of that meeting.

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