Correlation between Macular Blood Flow and Central Visual Sensitivity in Retinitis Pigmentosa

Abstract

Purpose: To investigate the changes in macular blood flow and the correlation between those changes and central visual function in patients with retinitis pigmentosa (RP).

Methods: The mean blur ratio (MBR), a quantitative blurring index of the laser speckle pattern that represents retinal and choroidal blood flow, was measured by laser speckle flowgraphy. MBR values in the macular area were compared between 12 RP patients and 12 control subjects. The relationships between MBR on the one hand and, on the other, visual acuity (VA), mean deviation (MD), and averaged macular sensitivity of static perimetry tests (Humphrey Filed Analyzer, the central 10-2 program) were analyzed in 48 RP patients.

Results: Macular MBR was decreased to 60% in RP patients compared with control subjects (P = 0.0011, Student’s t-test). Spearman rank testing and age- and gender-adjusted linear regression analysis showed that macular MBR was significantly correlated with MD values (r = 0.572, P < 0.0001; r2 = 0.216, P = 0.0010) as well as with averaged macular sensitivity at the central 4 and 12 points of static perimetry tests (r = 0.524 and 0.537, P = 0.0002 and 0.0001; r2 = 0.177 and 0.130, P = 0.0031 and 0.0111, respectively), but not with VA (r = -0.120, P = 0.5362; r2 = -0.012, P = 0.7094).

Conclusions: Decreased macular blood flow was associated with reduced macular visual sensitivity in RP patients. These findings suggest that vascular defects may underlie the loss of cone-mediated central visual function in RP.

Keywords: 688 retina • 696 retinal degenerations: hereditary