Topical versus oral carbonic anhydrase inhibitor therapy for pediatric glaucoma

Abstract

Purpose: Our purpose was to compare, in a crossover design, the hypotensive effect of oral acetazolamide (Diamox) and topical dorzolamide (Trusopt) in patients with pediatric glaucoma. Methods: All patients less than 18 years old who were switched from acetazolamide to dorzolamide without other intervention were reviewed. Intraocular pressures were obtained with either a Tono-Pen (Mentor Ophthalmics, Santa Barbara, Calif.) or applanation tonometer. Minimum follow-up times on acetazolamide and on dorzolamide were 1 month (mean 12.2±19.7 months) and 2 months (mean 8.2±5.1 months), respectively. The average dose of acetazolamide was 9.9±1.8 mg/kg/day. Results: Eleven eyes (11 patients) were included. Indications for crossover from oral to topical carbonic anhydrase inhibitor (CAl) therapy were intolerance to acetazolamide (6 eyes) and surgical intervention in the fellow eye (5 eyes). The mean age at the time of crossover was 7.4±3.0 years. A comparison of intraocular pressure (IOP) before addition of a CAI was made in 8 eyes. The mean IOP off of a CAI was 27.8±4.9 mm Hg. The mean IOP was reduced to 18.5±4.3 mm Hg on acetazolamide (mean percent IOP reduction 35.7%±15.6%, p<0.01) and to 22.2±5.4 mm Hg on dorzolamide (mean percent IOP reduction 27.4%±17.1%, p < 0.01). All 11 eyes showed an increase in IOP when switched from acetazolamide to dorzolamide, with a mean increase of 3.7±2.5 mm Hg (20.2%±13.7%, p < 0.01). Five eyes have remained controlled on dorzolamide and a topical β-blocker. Five eyes required further intervention for the control of glaucoma. One eye was switched back to acetazolamide for better IOP control. Conclusion: Although not as effective as oral acetazolamide, topical dorzolamide causes a significant IOP reduction in this group of pediatric glaucoma patients and appears to be well tolerated.