Background To characterise the contrast sensitivity function (CSF) in central serous chorioretinopathy (CSCR) compared with healthy controls using novel computerised contrast sensitivity (CS) testing with active learning algorithms.

Methods Prospective observational study measuring CSF in CSCR eyes and controls using the Manifold Platform (Adaptive Sensory Technology, San Diego, California). Mixed effects multivariate regression models were used. Outcomes included area under the log CSF (AULCSF), CS thresholds at 1, 1.5, 3, 12 and 18 cycles per degree (cpd) and best-corrected visual acuity (BCVA). Associations of contrast outcomes with structural findings on optical coherence tomography (OCT) and subjective symptomatology were investigated.

Results Forty CSCR eyes and 89 controls were included with median BCVA logarithm of median angle of resolution 0.10 (20/25) versus 0.00 (20/20), respectively (p=0.01). When accounting for age, CSCR was associated with significantly reduced median AULCSF (p=0.02, β=−0.14) and reduced CS thresholds at 6 cpd (p=0.009, β=−0.18), 12 cpd (p<0.001, β=−0.23) and 18 cpd (p=0.04, β=−0.09), versus controls. Within the CSCR group, subjectively perceived visual impairment (N=22) was associated with significantly decreased CS thresholds at all spatial frequencies and in AULCSF compared with asymptomatic CSCR eyes (N=18). Ellipsoid zone attenuation and subfoveal fluid on OCT were associated with decreased AULCSF and CS thresholds specifically at 3, 6 and 12 cpd, whereas presence of extrafoveal fluid at 1.5 and 3 cpd.

Conclusion Contrast sensitivity is significantly reduced in CSCR, and strongly correlates with subjective visual impairment. Different structural biomarkers correlate with contrast thresholds reductions at different spatial frequencies.