Scheie Eye Institute, University of Pennsylvania
Dry eye and dry age-related macular degeneration 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.
Dry eye develops when the tear film covering the front of the eye drys 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!
Dry Eye affects millions of people worldwide, and is one of the most common reasons that patients visit their eye doctor. Our tears are a complex mixture of water, oils and mucus. When vision is healthy a balance exists between the tear layers. If an imbalance occurs with one or more of the tear layers the tear system breaks down and dry spots develop. This is called Dry Eye and occurs due to insufficient production of tears, or excessive evaporation of the tear film. Dry Eyes are uncomfortable and can impact vision throughout the day. Patients who suffer from chronic Dry Eye find it difficult to perform everyday activities, which can significantly decrease their quality of life. Dry Eyes occur for a number of different reasons. These include age, gender, medications, and environmental conditions. Other factors include long term contact lens use, and refractive procedures such as LASIK, which can cause decreased tear production. The key to managing Dry Eye is to recognize the symptoms early and seek treatment from an eye care professional. Without treatment, chronic dry eye can lead to impaired vision, eye infection and scarring.
There are two forms of age-related macular degeneration, wet AMD and dry AMD.
Wet 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 brolucizumab (Beovu®), ranibizumab (Lucenti®), aflibercept (Eylea®), or bevacizumab (Avastin®).
Dry AMD
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.
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.
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.
In summary, treatments for dry eye include:
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. Learn about treatments for dry macular degeneration.
Joshua Dunaief, MD, received his BA magna cum laude in Biology from Harvard (1987), MD/PhD from Columbia College of Physicians and Surgeons (1996), completed ophthalmology residency at the Wilmer Eye Institute, Johns Hopkins in 2000, and medical retina fellowship at Scheie Eye Institute, University of Pennsylvania in 2004.
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