Preoperative timolol and ocular compression in cataract surgery

The intraocular pressure (IOP) reducing effect of topical timolol with digital ocular compression for the prevention of vitreous loss in cataract surgery was compared with the effect of combined acetazolamide-mannitol pre-medication with digital compression. In the timolol group of 30 patients the mean IOP reduced from 11.4 mmHg before the compression to 8.2 mmHg after it. In the acetazolamide-mannitol group of 29 patients the mean IOPs were 10.9 and 5.6 mmHg, respectively. The reduction of IOP was statistically highly significant in both groups. There was no case of vitreous loss and the post-operative healing was uncomplicated in both groups of patients. The application of timolol was easy and time saving, but acetazolamide-mannitol pre-medication created deeper hypotony after ocular compression, which was probably due to the vitreous reducing effect of mannitol.