Effect of a Preservative-free Dorzolamide/Timolol Fixed Combination on Elevated Intraocular Pressure after Vitrectomy

Purpose: To verify the effect of preservative-free Dorzolamide/Timolol fixed combination (PFDTC) on intraocular pressure (IOP) elevation after vitrectomy. Methods: We retrospectively reviewed medical records of 33 patients who used PFDTC after pars plana vitrectomy. All patients' visual acuity and IOP was measured and symptoms of conjunctival irritation were investigated through survey and slit lamp examination. Results: Before vitrectomy, the mean IOP was 13.6 +/- 4.4 mm Hg which was elevated to 31.7 +/- 5.4 mm Hg after vitrectomy (p < 0.001) and applying eyedrop lowered the mean IOP to 17.2 +/- 7.0 mm Hg (p < 0.001). Regardless of tamponade material type, all elevated IOP decreased (p < 0.001) and the IOP of all 33 eyes did not rise to over 30 mm Hg again. No additional surgery for IOP control was needed during two-month follow-up period. Of the 33 patients using PFDTC, patients who felt discomfort were five (15.2%) and no patients showed side effects severe enough to stop use of eyedrop. Conclusions: PFDTC is an anti-glaucomatic agent which can reduce the IOP by inhibiting aqueous humor production. Without need for additional surgery, the eyedrop can effectively lower elevated post-vitrectomy IOP, with expectation of good patient compliance due to low risk of conjunctival irritation.