Optical gap a potential biomarker in cone-dominant retinal dystrophy

In this retrospective cohort study, 36 patients with an optical gap on spectral-domain optical coherence tomography (OCT) with a confirmed diagnosis of inherited retinal dystrophy, were included.

Using the caliper tool on Heidelberg Explorer, the width and height of the gaps in 70 eyes were measured by 2 independent graders. Outer and central retinal thickness measurements were also recorded.

In patients with Stargardt disease, achromatopsia, occult macular dystrophy, and cone dystrophies, the progressive nature of optical gaps was confirmed. In patients with Stargardt disease and cone dystrophies larger changes in gap width were seen compared to those seen in patients with achromatopsia and occult macular dystrophy. In patients with Stargardt disease, gap heigh decreased, however, it increased in patients with achromatopsia and occult macular dystrophy.

The authors concluded, “The optical gap is a progressive phenotype seen in an increasing number of etiologies. This progressive nature suggests a use as a biomarker in the understanding of disease progression. Interocular discordance of the phenotype may be a feature of Stargardt disease and cone dystrophies.”

Reference
Oh JK, Ryu J, Lima de Carvalho JR Jr, Levi SR, Lee W, Tsamis E, Greenstein VC, Mahajan VB, Allikmets R, Tsang SH. Optical Gap Biomarker in Cone-Dominant Retinal Dystrophy. Am J Ophthalmol. 2020;218:40-53. doi: 10.1016/j.ajo.2020.05.016.