Dry Eye Associated with Pingueculae and Pterygia
BY WILLIAM L. MILLER, OD, MS, PHD, FAAO
The most commonly accepted etiology for pterygia consists of ultraviolet (UVA and UVB) exposure and environmental factors such as dry and windy climates. Some of these same risk factors do not appear to be true for the development of pingueculae (Karai and Horiguchi 1984; Norm and Franck, 1991). This exposure leads to a degeneration of conjunctival stroma, with eventual activation of fibroblasts that invade the anterior limiting lamina and ultimately the corneal stroma (Dake et al, 1989). Pterygia most commonly occur between a patient’s third and fifth decade. Some researchers theorize that conjunctivochalasis, which is intimately associated with dry eye disease, is a precursor to pterygium formation (Tong et al, 2013).
The association of pingueculae and pterygia with dry eye disease is often overlooked. Pterygia more commonly cause or exacerbate dry eye disease. Many of the symptoms of pterygia and pingueculae are related to the disruption of the tear film and may include burning, stinging, itching, blurred vision, and foreign body sensation.
In patients who already have dry eye symptoms, the existence of pterygia can increase those symptoms (Hashemi et al, 2014). Continued dry eye disease also may exacerbate and encourage further growth of either pterygia or pingueculae. Local drying effects may potentiate the fibrovascular changes found in pterygia (Hilgers, 1960). One study demonstrated an increase in tear osmolarity in patients who have pterygia that may lead to goblet cell density changes (Julio et al, 2012). The existence of demodicidosis, a cause for dry eye disease, is also a risk factor for recurrent pterygia.
Management and Treatment
Treating and managing pingueculae- and pterygia-induced dry eye can be a challenge. After conservative treatment attempts, surgical management can eliminate the growths, but recurrence remains a problem. Surgery is often reserved for those unhappy about the aesthetic appearance of the lesions or in cases in which pterygia induces significant irregular astigmatism. Prudent corneal topography is helpful in recommending treatment and monitoring postsurgical outcomes. This can also be used to judge the effects of pterygia by performing serial noninvasive tear breakup times.
With mild cases of pingueculae and pterygia, surgery may not be optimal. In these cases, manage the patient’s dry eye symptoms and signs using topical tear supplements. Frequently used options include Refresh Optive (Allergan), Systane Ultra (Alcon), and Blink Tears (Abbott Medical Optics). It is best to prescribe precisely how often patients should use the drops. More viscous options for nighttime use include Genteal Gel (Alcon) and Refresh Liquigel (Allergan).
Contact lenses, soft or GP, can cover the growth to protect the surface from drying effects and, in some cases, from UV exposure. In cases of simultaneous localized inflammation, a topical steroid such as loteprednol etabonate ophthalmic suspension, 0.5% (Lotemax, Bausch + Lomb [B+L]) or 0.2% (Alrex, B+L) and rimexolone (Vexol, Alcon) may be indicated. This is typically a short-term addition to ameliorate the irritation with continued use of topical tear supplements during and after the inflammation has resolved. In addition, cyclosporine, 0.05% (Restasis, Allergan) prescribed twice a day may be an alternative with dry eye-induced pterygia and pingueculae. CLS
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Dr. Miller is an associate professor and chair of the Clinical Sciences Department at the University of Houston College of Optometry. He is a consultant or advisor to Alcon and Vistakon and has received research funding from Alcon and CooperVision, and lecture or authorship honoraria from Alcon and B+L. You can reach him at firstname.lastname@example.org.