Dry eye, corneal dystrophies common ocular surface diseases in older patients

Issue: May 2001

As a person grows older, the likelihood of developing some form of ocular surface disease increases due to age-related factors. Severe dry eye, corneal dystrophies and eyelid problems may be common. Practitioners treating older patients must consider the effects of long-term contact lens wear, exposure to the elements, eyelid laxity, the need for cataract surgery as well as economical issues.

Dry eye

Keratoconjunctivitis sicca, or dry eye, is one of the most common ocular surface diseases found in older individuals and may be exacerbated by corneal insensitivity, said Elmer Tu, MD, director of refractive surgery at the University of Illinois Eye Center in Chicago.

“Corneal insensitivity increases with age because of systemic and local disease,” he told Primary Care Optometry News. “Also, people who have been exposed to the elements over the years tend to experience more ocular irritation from alteration of the ocular surface.”

Older patients may develop conditions primarily associated with dryness such as punctate epithelial keratitis, said Richard Multack, OD, DO, clinical full professor and chairman of ophthalmology at Midwestern University, Chicago College of Osteopathic Medicine. “In some severe instances, mucus can become impacted in the epithelium,” he said.

Eyelid conditions

One of the first things to check for when examining an older patient is the condition of the eyelids. Check for blepharitis, eyelid position, any abnormalities such as ectropion or entropion, misdirected lashes or excessive lid laxity or exposure, said Dr. Tu. “Lid laxity is something that you find in older individuals — just because of time or age, their tissues tend to become a little more lax,” he said. “That contributes greatly to ocular surface disease in older patients.”

Take a detailed history of these patients and test them for both dry eye and blepharitis, said Dr. Tu. “Also take a history of previous eye surgery. They will be at a higher risk for ocular surface complications from that down the road,” he said. “These are issues you wouldn’t necessarily need to consider in younger patients.”

Corneal dystrophy, endothelial loss

Peripheral or marginal degeneration of the cornea, as well as certain corneal dystrophies, become somewhat common in older patients, said Dr. Multack. “A person can have some of the corneal dystrophies, such as Fuch’s dystrophy, his or her whole life, but the symptomatology becomes more evident the older a person gets, and that’s because you lose about 1% of your endothelial cells in the cornea per year of your life after age 70,” he said.

“Fuch’s is also a disease that destroys the endothelial cells, which are responsible for pumping the cornea dry,” he continued. “The condition caused when the pump fails, bullous keratopathy, is more likely to occur in the elderly due to the normal attrition of endothelial cells. When you’re 75, theoretically, you’ve lost 75% of your endothelial cells and you have a disease that’s affecting the remainder, so you’re more likely to have corneal decompensation when you’re older.”

Dr. Tu said that endothelial loss should not actually cause ocular surface disease until it reaches the late stages. “Once it gets to the point where a patient has corneal edema, it may exacerbate ocular surface disease, but usually the routine loss of endothelial cells won’t have much of an effect on the surface until it reaches a critical point,” he said.

Factors such as sun exposure and long-term contact lens wear can manifest in a variety of conditions in the elderly as well, said Dr. Tu. “Sun exposure can cause a limbal deficiency syndrome, where the limbal tissue around the cornea is not sufficient to maintain a normal corneal epithelium. This can manifest either in run-of-the-mill conditions such as a pterygium, or just a deficient corneal epithelium from lack of normal, healthy cells,” he said.

LASIK: an upper age limit?

Dr. Multack advises against LASIK in older patients. “We’re not sure exactly what the procedure does to the endothelium, which is already potentially damaged by age,” he said. “I believe LASIK is not a good procedure for older people, anyway. Older myopes can take off their glasses to read. When you have LASIK, you need to wear reading glasses because you’re a presbyope, and there’s no simple way to deal with presbyopia with laser surgery at this point.

“Laser thermokeratoplasty is being used for presbyopia, but it is not completely predictable,” he continued. “It works on mildly myopic presbyopes. If a patient is farsighted, that’s another story, because he or she is probably wearing reading glasses already.”

Dr. Tu added that refractive surgery patients with corneal insensitivity do not tear as much. “It’s a vicious cycle,” he said. “When you have a neurotrophic keratitis or relative insensitivity, the driving force for tearing isn’t there, so they tend to get a drier corneal surface than most other LASIK patients.”

It is likely that LASIK can exacerbate a pre-existing dry eye condition, the doctors agreed, due to the corneal nerves being cut, which causes corneal desensitization and, therefore, reduced blinking.

A patient with cataracts also would not make a good candidate for LASIK, Dr. Tu said. Certain types of cataracts can cause myopia. In those cases, he recommends cataract surgery, which will also correct the myopia. “If a patient who has had cataract surgery ends up being nearsighted in one eye, LASIK would be a very good procedure for that patient, as long as the ocular surface is relatively normal,” he said.

Personal patient management

Sometimes a patient’s age plays a role in the time necessary to complete the exam. Dr. Multack noted that older patients may have more time to spare and therefore may want to talk more with the doctor. On the flip side, Dr. Tu said that he finds that older patients may, in fact, be less demanding than their younger counterparts and therefore need less time in the chair. “Younger individuals tend to ask more questions and want more explicit detail,” he said.

Considering an older patient’s mobility and coordination often helps when prescribing medications, said Dr. Tu. Ease of use should be high on the list.

“Sometimes older individuals aren’t able to administer drops as a younger person can, so keep that in mind when you’re suggesting types of drops,” he said. “Sometimes preservative-free preparations are in small vials that older patients can’t handle very well. You might have to be more aggressive with those patients in performing punctal occlusion or prescribing ointments instead of drops. If lid problems are a contributing factor, as is often the case in older individuals, surgical intervention can often help stabilize the surface, often by tightening the eyelids or closing them down a bit to prevent exposure.”

Finally, financial matters often play a role in the care of an older patient, said Dr. Multack. “The medications that we use – even over-the-counter agents — are expensive,” he said. “Older patients often can’t afford them, and dry eye medications are not usually covered by insurance. That’s an issue you have to consider when you treat older patients.”

For Your Information:

Richard Multack, OD, DO, may be reached at St. James Hospital, Olympia Fields, KS 60461; (708) 747-4000, ext. 1612; fax: (708) 283-9116; e-mail: ofomc@aol.com.

Elmer Tu, MD, may be reached at 1855 West Taylor St., MC648, Room #3.164, Chicago, IL 60612; (312) 996-8937; fax: (312) 355-4248.