 Patients are asked to abstain from alcohol and caffeine for at least 12 h before the LDF measurements. Systolic BPsyst and diastolic BPdiast blood pressures are determined DINAMAP, Critikon, inc. Tampa, Florida, USA during LDF measurements and immediately after, intraocular pressure IOP of the fellow eye is measured by applanation tonometry: using the Tonopen XL. The mean ocular perfusion pressure OPP is calculated according to the formula: OPP sitting position 95140 x MAP - IOP in which mean arterial pressure MAP was calculated as: MAP BPdiast 13 BPsyst - BPdiast. 