Background: Intraocular pressure (IOP) rise is the most common complication of Nd YAG laser posterior capsulotomy, and the aim of this study was to compare the effect of oral acetazolamide versus topical Co-biosopt in preventing IOP rise following Nd YAG laser posterior capsulotomy.

Materials and Methods: This clinical trial was done on 200 patients who underwent laser Nd: YAG capsulotomy. First group received oral acetazolamide 250 mg q 6h and placebo drops q 8h and second group received Co-biosopt) timolol 0/5% and dorzolamide 2%) drops q 8h and oral placebo capsule q 6h. IOP was measured before and 24 hours after laser capsulotomy.

Results: Mean IOP of right and left eye 24 hours after capsulotomy in the acetazolamide group was significantly decreased as compared to the previous (p=0.001) and in Co-Biosopt group the values 24 hours after capsulotomy was significantly decreased as compared with the previous in right and left eye (p=0.001).

Conclusion: According to oral acetazolamide side effects and desirable IOP reduction with Co-Biosopt that recently entered to Iran’s market and have typical domestic, this medication can be an option for preventing IOP rise after laser capsulotomy in a patient with posterior capsular opacification.