Comparison of Oral Carbonic Anhydrase Inhibitor with Topical Carbonic Anhydrase Inhibitor in Central Serous Chorioretinopathy

Abstract

Background: Central serous chorioretinopathy (CSC) is a disorder of the retina that causes a collection of fluid under the retina, which affects vision. The use of carbonic anhydrase inhibitors to improve the function of the pump in the retinal pigment epithelium and to promote fluid reabsorption. Comparative evidence comparing oral and topical formulation is however limited.

Objective: To compare the efficacy and safety of oral acetazolamide versus topical dorzolamide in the management of CSC.

Study Design: The study was prospective, randomized and comparative in a tertiary care ophthalmology department.

Methods: The study was conducted over a 12-month period, which involved 100 patients with the diagnosis of CSC. Patients were divided into two groups: one that received oral acetazolamide, 250 mg twice daily; and a second that received topical dorzolamide, 2% eye drops, three times a day, for 8 weeks. The outcomes measured were the changes in best corrected visual acuity (BCVA), central macular thickness (CMT), resolution of subretinal fluid (SRF), and adverse effects. Appropriate statistical tests were used and p < 0.05 was taken to be significant.

Results: A significant improvement in BCVA and a decrease in CMT (p<0.001) was observed in both treatment groups. Compared to the topical dorzolamide group, the oral acetazolamide group showed significant improvements in BCVA (0.31 ± 0.10 vs 0.24 ± 0.09 logMAR), more deep retinal layers thinning with CMT (146 ± 42 µm vs 116 ± 37 µm), and a higher proportion of complete SRF resolution (78% vs 60%). But the oral group had more systemic complaints (paresthesias, gastrointestinal upset), while the topical group had more eye complaints.

Conclusion: Oral acetazolamide is more effective than topical dorzolamide in both anatomical and functional results in the treatment of CSC; however oral acetazolamide has greater systemic side effects. Dorzolamide can be used topically in some patients as an alternate therapy.