Corneal Changes During Pilocarpine Gel Therapy: Reply

Correspondence

Vol. 101, No.5

Corneal Changes During Pilocarpine Gel Therapy EDITOR:

In Chandler and Grant's! Glaucoma, a case of corneal epithelial haziness and superficial vascularization is described in association with pilocarpine eyedrop use. In their article, "Corneal changes during pilocarpine gel therapy" (Am. J. OphthalmoI. 101:13, Jan. 1986), D. H. Johnson, K. R. Kenyon, D. 1. Epstein, and E. M. Van Buskirk questioned whether this was secondary to the drug or to the chlorobutanol preservative. The occurrence of similar changes with pilocarpine gel (with no chlorobutanol) would seem to implicate the drug itself in this rare, apparently idiosyncratic reaction. STEPHEN R. HOOK, M.D.

Houston, Texas

Reference 1. Chandler, P. A., and Grant, W. M.: Glaucoma. Philadelphia, Lea and Febiger, 1979, p. 88.

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EDITOR:

Chandler and Grant! described a patient with marked reduction of vision whose eyes "were generally quite red with enlarged follicles in the lower fornices." Additionally, the conjunctiva appeared opaque and milky and "superficial vessels came in from all sides almost to the border of a 2-mm pupil." In our series eyes were not red and neither follicles nor corneal vascularization was present. We have seen corneal changes similar to those we described in our article in several patients using the gel vehicle alone (no pilocarpine added) as a treatment for dry eyes. Another point that we believe implicates the gel vehicle and not pilocarpine itself is that corneal changes have not been reported with Ocuserts which use continuous pilocarpine supply and release. We appeciate Dr. Hook's interest and keen eye in pointing out the case of Chandler and Grant, but believe the corneal change in our series resulted from a different mechanism.

DOUGLAS H. JOHNSON, M.D.

Rochester, Minnesota

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Reference 1. Chandler, P. A., and Grant, W. M.: Glaucoma. Philadelphia, Lea and Febiger, 1979, p. 88.

An Unusual Corneal Complication of Soft Contact Lens EDITOR:

In their article, "An unusual corneal complication of soft contact lens" (Am. J. OphthalmoL 100:794, Dec. 1985), C. S. Horowitz, J. Lin, and H. C. Chew reported studying 13 patients wearing soft contact lenses who developed an arc-like opacity in the upper cornea. Most had tight eyelids. They also mentioned the close relationship between these complications and one characteristic of the soft contact lenses involved in these reports -a well-defined transition zone between the optic and the haptic zone. An analysis of their summary of clinical data and data on contact lenses (Tables 1 and 2), makes it obvious that all the soft contact lenses involved were lathe-cut and not higher than -9.00 diopters. At the same time they recommended switching to gas-permeable hard contact lenses to avoid these complications. We strongly disagree with 'OUT colleagues, taking into consideration that they did not mention whether they tried spin-cast lenses. All the ultrathin spin-cast soft contact lenses under -9.00 diopters have no haptic zone. In the past eight years we have fitted the two types of spin-cast ultrathin lenses' (the 75-/-Lm and the 35-/-Lm types with 39% water content, in two diameters, 13.5 and 14.5 mm, with both thermal and chemical sterilization) in a little over 2,000 cases, and we never observed the abovementioned complication. In our opinion, the lens of choice for first or secondary fitting to stay away from the arc-like upper corneal opacity is the spin-cast soft contact lens.

ARTURO S. CHAYET, M.D. JOSE CHAYET V., M.D.

Mexico City, Mexico

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We thank Dr. A. S. Chayet and Dr. J. Chayet V. for their comments. Although the