Retinal sensitivity is a valuable complementary measurement to visual acuity — a microperimetry study in patients with maculopathies

Purpose: To evaluate changes in macular sensitivity, as measured with microperimetry, among patients with maculopathy and stable visual acuity (VA). Methods: Macular sensitivity was assessed using the Spectral OCT/SLO™ microperimetry (OCT/SLO, Optos Plc., Dunfermline, UK) in 25 eyes (16 patients) with maculopathy and stable VA (<5 letters change in ETDRS score) at two consecutive clinic visits. To take the limits of the test–retest repeatability of the OCT/SLO into account, coefficient of repeatability (CoR) was employed to estimate the probability of the sensitivity changes being secondary to measurement noise. Results: The point sensitivity changes were statistically significant (Wilcoxon signed-rank test, P < 0.001). Seventy-seven points (11 %) out of a total of 700 sensitivity points had a genuine sensitivity change, with a mean increase of 8.6 ± 2.6 dB in 35 points and a mean decrease of 7.9 ± 2.2 dB in 42 points. Conclusions: Point-to-point change in macular sensitivity can be used as a biomarker of changes in disease activity in patients with maculopathy, and can be more accurate than either mean sensitivity or BCVA in detection of changes in macular function. The measurement variability should be considered when observing the local sensitivity changes.