Hardy-Rand-Rittler colour vision testing in cone and cone-rod dystrophies: correlation with structural and functional outcome measures.

PURPOSE

To determine how Hardy-Rand-Rittler (HRR) colour vision testing correlates with visual functional and structural assessments in Cone and Cone-Rod Dystrophy.

METHODS

Thirty-four Cone and 69 Cone-Rod Dystrophy patients diagnosed by electroretinography (ERG) at the Save Sight Institute in Sydney were included in a retrospective analysis. Each patient's HRR colour vision test scores were compared with markers of cone and rod system function including visual acuity (VA), ERG responses, changes on Spectral Domain Optical Coherence Tomography (OCT) and Fundus Autofluorescence.

RESULTS

The number of plates identified on HRR testing correlated with logMAR best-corrected distance VA; r(101) = -0.49, p < 0.0001. HRR scores correlated with markers of cone and macula function including OCT Ellipsoid Zone Gap Width, Central Macular and Outer Nuclear Layer Thickness, Full Field ERG 30 Hz flicker amplitudes, light adapted 3.0 b-wave amplitudes and Pattern ERG 15- and 30-degree p50 amplitudes.

CONCLUSION

HRR colour vision testing correlates with structural and functional measures in Cone and Cone-Rod Dystrophy. HRR colour vision testing provides a simple clinic-based option to monitor disease changes in Cone and Cone-Rod Dystrophy patients, especially when ERG testing is not available.