In vivo High–Resolution Imaging of Retinal Dystrophy With Different Adaptive Optics Imaging Modalities

Abstract

Purpose: : To study microscopic retinal changes in living eyes with various forms of retinal dystrophy by using high resolution imaging modalities that include high–resolution Fourier–domain optical coherence tomography (Fd–OCT) and novel adaptive optics (AO) OCT in addition to a previously described AO fundus camera.

Methods: : Patients with different forms of retinal dystrophies were recruited for the study, including cone–rod dystrophy, rod–cone dystrophy, cone dystrophy and juvenile macular dystrophy. The high–resolution Fd–OCT and AO–OCT instruments were used to obtain cross–sectional tomograms (B–scans) as well as 3D volumes of the retina. These images were compared with en–face images of photoreceptors obtained with the existing AO fundus camera. Retinal images were acquired at several retinal eccentricities that varied in disease severity. Identical retinal locations were imaged using all 3 instruments.

Results: : The AO images clearly revealed losses of cones that were correlated with localized functional changes including contrast sensitivity, multifocal ERG and visual field sensitivity. The high–resolution Fd–OCT images also showed changes in the photoreceptor layer at the corresponding locations. Furthermore, the AO–OCT showed irregularities in the arrangement of cone photoreceptors in these patients while retinal layers anterior to the photoreceptor layer were unaffected. The 3D reconstruction of OCT images provides an alternative global view of the retina.

Conclusions: : Combining all three high–resolution imaging modalities permits a more comprehensive analysis of the retina at a resolution level that has previously only been possible through histology.

Keywords: retina • photoreceptors • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)