Effect of squatting on sub-foveolar blood flow in pseudophakic eyes operated by scleral buckling procedure - a masked study

Ziel: To investigate the relationship between velocity (Vel,h), blood volume (Vol(ch)) and blood flow (F-ch), and the mean ocular perfusion pressure (PPm) in the foveal region, and to determine how the regulatory capacity of the choroidal circulation is affected after an encircling buckle procedure. Methods: We investigated both pseudophakic eyes of 6 patients (age range 56-79 years) in a masked study. Subjects presenting eye diseases (glaucoma, uveitis, diabetic retinopathy) as well as systemic diseases were excluded from the study. All subjects had in one eye a successful management of retinal detachment with an encircling buckling; the second eye was considered as control. Measurements of Vel(ch), Vol(ch) and F-ch were obtained by Laser Doppler Flowmetry (LDF) at baseline and during isometric excercise (squatting). Results: In the operated eyes, Vel(ch) and F-ch increased significantly (ANOVA, p <0.05) during the PPm raise, which was not the case for Vol(ch) (ANOVA, p > 0.05). In the control eyes, all hemodynamic parameters remained unaffected by the PPm increase (ANOVA, p > 0.05). The response of Vel(ch) and F-ch was significantly different (ANCOVA, p < 0.002) between operated and control eyes. Conclusion: These results suggest that encircling buckle does affect subfoveal choroidal blood flow regulation, which may explain a possible macular dysfunction in the operated eyes.