Cone structure and retinal sensitivity assessment in patients with red-green colour vision deficiency using multimodal imaging.

BACKGROUND/AIMS: To evaluate cone morphology, retinal sublayer thicknesses and vessel density (VD) and their associations with retinal sensitivity (RS) in red-green colour vision deficiency (CVD).

METHODS

36 patients with red-green CVD and 38 age-matched controls were enrolled. Diagnosis was confirmed by pseudoisochromatic plates and the Farnsworth-Munsell 100-hue test. All participants underwent adaptive optics scanning laser ophthalmoscopy (AO-SLO), optical coherence tomography (OCT), OCT-angiography and microperimetry.

RESULTS

Patients with red-green CVD exhibited significantly decreased cone density and regularity, increased cone dispersion and spacing at 3° eccentricity, and thinner myoid and ellipsoid zone (MEZ) and outer segment (OS) (all p<0.01). VDs, blue-yellow error score and axial length did not differ between groups. Patients with CVD had higher red-green error scores and lower RS (p<0.05). Temporal cone density was correlated with RS only in CVD (r=0.410, p=0.011). Mean cone density correlated with favourable cone parameters and MEZ thickness (r=-0.827 to 0.862, p<0.005) and predicted higher RS (r=0.463, p<0.001).

CONCLUSION

Red-green CVD features reduced cone density, disorganised arrangement and MEZ and OS thinning, which are closely linked to RS. Cone structural integrity has clinical value for managing visual impairments in CVD.