Effect of Pharmacological Pupil Dilation on Dark-Adapted Perimetric Sensitivity in Healthy Subjects Using an Octopus...

To determine whether dilation status has a clinically meaningful effect on sensitivity in normal subjects undergoing two-color dark-adapted perimetry, which can be useful to assess rod function.

A perimeter measured naturally and pharmacologically dilated scotopic sensitivities using a test grid consisting of 16 points across the horizontal meridian ranging from 60° temporal to 45° nasal using cyan (500 nm wavelength) or red (650 nm wavelength) stimuli. The primary outcome was average overall sensitivity based on dilation status, which was compared using a linear mixed effect model for each color stimuli. A difference of 2 dB or more was considered clinically significant.

Twenty-nine eyes from 15 subjects (nine female) ages 23 to 63 with no known retinal pathology were included. Pharmacologically dilated eyes were 0.54 dB (95% confidence interval [CI], 0.05 dB to 1.03 dB; P = 0.032) more sensitive to a red stimulus than naturally dilated eyes, but this was not statistically significant after correction for multiple comparisons. Pharmacologically dilated eyes were 0.03 dB (95% CI, -0.20 dB to 0.14 dB; P = 0.734) less sensitive to a cyan stimulus compared to naturally dilated eyes.

These findings show no clinically significant differences in sensitivity of scotopic perimetry in eyes without retinal pathology based on dilation status for both cyan and red stimuli.

In this study, pharmacological dilation did not have a clinically meaningful effect on sensitivity, suggesting that this is not necessary when using two-color dark-adapted perimetry to assess for rod function.