Purchase this article with an account.
S. Linguerri, A.L. Parmeggiani, B. Falsini, C.E. Riva; Effect of Timolol Maleate on Subfoveal Choroidal Blood Flow as Measured by Laser Doppler Flowmetry (LDF) . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4471.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the effect of timolol maleate on subfoveal choroidal blood flow (ChBF) and choroidal vascular resistance (ChBR) in a group of normal subjects.
. In 12 healthy subjects with average age of 35 ± 8 (95 %cim) years, a drop of either timolol maleate 0.5 % or a placebo was administered in a masked fashion in one eye chosen at random. Two weeks later, the other drop was instilled in the same eye. Subfoveal ChBF in the choriocapillaries behind the fovea was measured for at least 1 min by LDF in both eyes at baseline and approximately every half hour during a 2–hour period following the instillation of the drop. The DC signal was kept as constant as possible between recordings and sessions for each eye. ChBR was defined as PPm/ChBF, where PPm is the mean ocular perfusion pressure. Brachial artery blood pressure, IOP and heart rate were determined at baseline and at the end of the measurements.
There was a significant (p = 0.002) decrease in IOP by approximately 2 mm in the timolol eye 90 min after instillation of the drop. The changes in ChBF and ChBR were not significantly different in the eyes with timolol and those with placebo (11 ± 20 % and –9 ± 10 %, respectively for ChBF; 4 ±19%and 12 ± 12 %, respectively for ChBR). We found a significantly greater ChBF (respectively smaller ChBR) change in the timolol eye relative to the corresponding values in the fellow eye (p = 0.025 for ChBF and p = 0.05 for ChBR). For our group of 12 subjects, the sensitivity of the technique, i.e. the smallest change in ChBF detectable by the technique was determined to be approximately 5 %.
This study shows that, compared to a placebo, one drop of timolol 0.5 % produces no detectable effect on subfoveal choroidal blood flow and vascular resistance in normal subjects.
This PDF is available to Subscribers Only