Abstract
Purpose: :
To investigate outer retinal pathologic features of occult macular dystrophy (OMD) using multimodal imaging modalities including spectral domain optical coherence tomography (SD-OCT), infrared (IR) reflectance, and autofluorescence (AF).
Methods: :
Qualitative and quantitative features on SD-OCT were investigated retrospectively in patients with OMD. Abnormal findings in IR reflectance, AF, and IR-AF were correlated with SD-OCT findings. The association between abnormal features of multimodal imaging modalities and visual function was analyzed.
Results: :
Quantitative features of SD-OCT included decreased thickness of outer nuclear layer, photoreceptor, and central fovea. Qualitative features consisted of central loss of cone outer segment tips, low reflectivity of inner segment (IS) - outer segment (OS) junction around macula, discontinuous layer of IS-OS junction, and disruption of external limiting membrane. Fourteen of nineteen eyes (73.7%) showed a round area with low IR reflectance around fovea. The area corresponded to the area with IS-OS disruption in SD-OCT and showed a decreased electrophysiologic response on multifocal electroretinography. Visual acuities were also associated with abnormalities in IR reflectance and SD-OCT: photoreceptor layer thickness significantly correlated with visual acuities and patients showing low IR reflectance showed significantly worse visual acuities. Fundus AF showed no abnormalities which indicate the sparing of retinal pigment epithelium (RPE) in the pathology of OMD.
Conclusions: :
IR imaging as well as SD-OCT is valuable for easy, non-invasive diagnosis and evaluating the progression of OMD. Abnormal findings on IR imaging without abnormalities in AF suggest the involvement of photoreceptors sparing RPE in the pathogenesis of OMD.
Keywords: age-related macular degeneration