Dry eye is one of the most common ocular conditions in the United States, and one of the top reasons patients visit an eye doctor. And, as physicians, we’re often trained that the simplest explanation for symptoms is the correct one. So, when a patient’s symptoms and initial examination point to dry eye, it’s natural to accept that as the definitive diagnosis. But occasionally, we need to take a closer look.
If your practice includes a Dry Eye Center of Excellence, you’ll most likely see patients with symptoms that present like dry eye, but in fact are caused by one of the many conditions that mirror, or occur in conjunction with, dry eye. A few of those include:
Recurrent corneal erosions. This is a recurring condition in which weak adhesion between the epithelial basement membrane and Bowman’s layer causes the epithelial layer of the cornea to break down. RCE often results from minor corneal trauma, such as scratches caused by organic material like fingernails, paper, plant stems, etc., or is due to anterior basement membrane dystrophy (AMBD). Symptoms include pain upon waking up, photophobia, tearing, blurred vision, redness, burning, blepharospasm and a feeling of something in the eye.
• Therapeutic contact lenses may help repair adhesion.
• Topical corticosteroids can help prevent RCE recurrence.
• Photo-therapeutic keratectomy (PTK) can relieve symptoms and increase visual acuity. PTK works by removing tissue from Bowman’s layer in order to facilitate creation of a new, potentially stronger basement membrane.
• Superficial keratectomy (SK) with or without stromal puncture can be a less-expensive treatment alternative to PTK, with similar results. Stromal puncture can only be performed if the recurrent erosion is peripheral, as the small scars can decrease vision.
Filamentary keratitis is a comparatively uncommon condition characterized by degenerated filaments of epithelial cells and mucous on the cornea, which can compromise vision and cause pain. Often filamentary keratitis results from other ocular conditions, such as autoimmune disorders and allergic reactions. Filamentary keratitis is most often seen along with severe cases of aqueous-deficient dry eye (ADDE). Symptoms include pain, and excessive production of mucous and debris.
• Removing the filaments, which can be accomplished using forceps or with a cellulose acetate sponge, can relieve symptoms.
• As with dry eye, artificial tear supplements are typically part of treatment of filamentary keratitis. In the case of filamentary keratitis, drops that include sodium hyaluronate and polyacrylic acid, which enable them to stay on the eye longer, are most beneficial.
• Punctal occlusion can improve tear retention and prevent further damage to the corneal surface.
• Because inflammation is a major contributor to filamentary keratitis, anti-inflammatory agents are an important component of treatment.
• Some practitioners have noted success in treating filamentary keratitis with injections of botulinum toxin in the lids. This approach likely works by causing the orbicularis muscle to relax, which in turn decreases eyelid pressure and blink frequency.
Mucus Fishing Syndrome is a chronic condition that got its name because patients afflicted with it often “fish” mucus from the eye. MFS is caused by conditions including dry eye, hypersensitivity related to contact lens irritation, or ocular trauma, which trigger the production of excess mucus. The excess mucus is irritating, so the patient attempts to remove it, which creates additional irritation and potentially introduces foreign substances, which exacerbates the condition.
• Key to treatment of MFS is identifying the source of the irritation. Often that source is dry eye.
• Mucolytic agents can reduce mucus production.
• With this condition, it is crucial to educate the patient about the importance of reducing the mucus “fishing,” which causes additional irritation.
Exposure Keratitis Due to Nocturnal Lagophthalmos is a common condition that frequently is overlooked. It is more prevalent in patients over 50, because changes in the lids and periorbital tissues brought on by aging keep the lids from closing completely at night. It is also more likely to occur after ocular surgery, such as cataract surgery, as the older patients’ lids are stretched by the speculum.
• Nighttime ointments are effective in most cases. The patient must apply them just before sleep, as they will blur vision for 30 to 120 minutes afterward. Patients should reapply the ointment if they get up in the middle of the night.
• Some patients do not respond well to ointment and/or cannot apply it and must have oculoplastic surgery to address the problem.
Marguerite McDonald, MD, FACS, with OCLI on Long Island, NY, is clinical professor of Ophthalmology at NYU Langone Medical Center, NY, and clinical professor of Ophthalmology at Tulane University Health Sciences Center, New Orleans, Louisiana.