Dry eye and dry age-related macular degeneration (AMD) are two conditions that occur more frequently as people age. This article discusses the causes and treatments for dry eye, and whether the condition is related to dry AMD.
Background: The Two Forms of AMD
Patients with wet AMD have new blood vessels that grow into the retina, which is in the back of the eye. These vessels can leak and bleed, causing problems. The leakage can often be stopped by intraocular injections of ranibizumab (Lucenti®), aflibercept (Eylea®), or bevacizumab (Avastin®).
In contrast, patients with dry AMD have deposits in the retina, called drusen, which contain proteins and lipids (naturally occurring molecules that include fats). Sometimes the drusen causes atrophy (death of some of the retinal cells). Dry AMD is a completely different condition from dry eye.
What is Dry Eye?
Patients with dry eye have a problem with the tear film covering the front of the eye, causing it to dry out. It occurs most often in the winter, when the air is dry. It can also occur in summer, when a car air conditioner is blowing lots of air into the eyes, causing tear evaporation. This can be uncomfortable, causing a burning sensation and temporarily blurred vision.
The burning sensation in dry eye is caused by stimulation of nerves in the cornea, which are “unhappy” because the cornea needs the tear film for nourishment, lubrication, and anti-microbial defense. This stimulation will sometimes cause a reflexive flood of tears, causing the dry eye patient to temporarily have very wet eyes!
Video: Dry Eye Overview
Causes of Dry Eye
Dry eye can have a number of different causes. One is inadequate production of the watery component of tears. Another cause is blockage of the tiny meibomian glands in the eyelids that produce lipids needed to coat the tears and delay their evaporation. A third is inflammation of the ocular surface.
The extreme case of inflammation-associated dry eye is caused by an auto-immune disease called Sjogren’s. Inflammation contributes to dry eye in at least 20 percent of patients, and they may be helped with anti-inflammatory eye drops. Dry eye can also be caused by LASIK surgery, medications for anxiety, Parkinson’s disease, and high blood pressure or by antihistamines, decongestants, antidepressants, and hormone replacement therapy.
Treatment for Dry Eye
Some people develop clogged meibomian glands, which produce an oily substance that prevents evaporation of the eye's tear film. Using a warm, wet washcloth applied to the eye lids for five minutes twice a day can be helpful. Oral doxycycline might also be prescribed by an ophthalmologist to loosen the secretions that are clogging the glands.
Artificial tears can provide temporary relief. The ones that come in single-dose vials are best, because they do not contain potentially irritating preservatives, but they are expensive. Alternatively, many patients like the multi-dose droppers. Artificial tears come in different levels of thickness, with the thicker ones providing longer-lasting relief, but blurring the vision initially. The thicker versions, such as gels or ointments, are best used immediately before bedtime.
Another treatment for dry eye is to block the tiny drains that remove tears from the surface of the eye. These four drains, called puncta, are located in the corners of the eyelids near the nose. They can be blocked temporarily with silicone plugs, or permanently closed with an in-office procedure.
While dry eye is common, and can be quite annoying, fortunately it has no connection to dry AMD. There is no evidence that patients with dry eye have an increased risk of dry AMD, or vice versa, although people may have both of these conditions, which are more common in people age 50 and older.
Macular Degeneration Resources:
- Macular Degeneration Toolkit (Helpful Information to Understand and Manage Macular Degeneration)
- Expert Information on Macular Degeneration (Articles)
- BrightFocus Chats (Audio Presentations on Macular Degeneration)
- What is Dry Macular Degeneration (Video)
- Macular Degeneration: Essential Facts (Publication)
This content was last updated on: October 24, 2018
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