Assessment of retinal arteriolar hemodynamics in patients pre‐ and post‐cataract extraction

Abstract

Abstract Purpose We have previously demonstrated that artificial light scatter results in the erroneous elevation of retinal vessel diameter and blood flow using densitometry based techniques. The aim of this study was to determine the impact of cataract on the quantitative, non‐invasive assessment of retinal arteriolar blood flow. Methods Of the original 30 recruited patients who were scheduled for extra‐capsular cataract extraction using phacoemulsification and intraocular lens implantation, ten patients between the ages of 61 and 84 (mean 73 ± 8) successfully completed the study protocol. Two visits were required to complete the study, one prior to the surgery and one at least six weeks after the surgery. Cataract status was documented using the Lens Opacity Classification System (LOCS, III) on the first visit. Retinal arteriolar hemodynamics were measured using the high intensity laser setting of the Canon Laser Blood Flowmeter (CLBF) on each visit. Results Group mean retinal arteriolar diameter and blood flow were significantly lower following extracapsular cataract extraction (Wilcoxon signed‐rank test, p=0.022 and p=0.028 respectively); however, centreline blood velocity was unchanged (Wilcoxon signed‐rank test, p=0.074). The primary reason for failure to complete the study protocol was due to poor retinal image quality impairing CLBF measurement. Conclusion Densitometry assessment of vessel diameter is extraneously impacted by the presence of cataract. Care needs to be exercised in the interpretation of studies of retinal vessel diameter and blood flow that utilize densitometry techniques.