Abstract
Abstract: :
Purpose: We previously used scanning laser Doppler flowmetry (SLDF) to demonstrate that neuroretinal rim perfusion is not significantly changed following therapeutic IOP reduction in ocular hypertension (OHT) (ARVO 2001, #114). Here, we studied the effect of topical dorzolamide 2% and timolol 0.5% on optic nerve head (ONH) and peripapillary retinal blood flow in OHT patients. Methods: Sixteen patients with OHT were evaluated for blood flow measurements before and after therapeutic IOP reduction. Patients underwent SLDF imaging before and after chronic therapy with dorzolamide (N=8) or timolol (N=8). Three patients in the dorzolamide group had dorzolamide 2% added to a timolol 0.5% baseline. All patients had intraocular pressure (IOP) reductions more than 20% and minimum of four weeks follow up. A mean of five blood flow measurements was obtained by SLDF full-field perfusion analysis using Heidelberg Retina Flowmeter images. Statistical analysis was performed using two-tailed distribution paired t-test. Results: There was no statistically significant difference between both study groups in age [p=0.76], IOP [p=0.07], cup/disc ratio [p=0.35] and visual field mean defect [p=0.34]. There was also no statistically significant difference between the two groups in the mean IOP after reduction [p=0.93], percentage of IOP reduction [p=0.17] and followup duration [p=0.35]. The timolol group had a mean IOP reduction of 35% after treatment. In these patients mean rim blood flow increased by 5% [p=0.84], while mean temporal peripapillary retinal flow decreased by 11% [p=0.30] and mean nasal peripapillary retinal flow increased by 5% [p=0.73]. The dorzolamide group had a mean IOP reduction of 26% after treatment. Mean rim blood flow showed an increase of 11%, [p=0.63]. Mean temporal peripapillary flow showed 9% increase and mean nasal peripapillary flow showed 7% increase [p=0.48 and 0.53 respectively]. Conclusion: OHT patients showed no significant changes in optic nerve head or peripapillary retinal blood flow following therapy with either topical dorzolamide 2% or timolol 0.5%.
Keywords: 390 drug toxicity/drug effects • 430 imaging/image analysis: clinical • 444 intraocular pressure