Abstract
Purpose: :
To demonstrate a method of assessment of photoreceptor dysfunction using OCT and to compare obtained results with microperimetry.
Methods: :
Data were obtained with the aid of high resolution, Spectral Domain OCT instrument constructed at Nicolaus Copernicus University. We introduced new software to perform segmentation of the junction between photoreceptor inner and outer segments (IS/OS). After segmentation, each cross-sectional image is transformed in such a way that posterior contour of the retina becomes a straight line but all radial distances within each cross-section are preserved. It enables us to display the distribution of light back-reflected intensity taken only from individual retinal layer located at specific distance from the reference plane and create en face reflectivity maps. We analysed the reflectivity maps corresponding to the IS/OS junction of 63 patients with photoreceptor dysfunction in course of age-related macular degeneration, central serous chorioretinopathy, solar maculopathy, macular holes, acute zonal occult outer retinopathy, multiple evanescent white dot syndrome, acute posterior multifocal placoid pigment epitheliopathy, drug-induced retinopathy and congenital disorders. OCT reflectivity maps of the IS/OS were correlated with fundus-related microperimetry (MP1, Nidek Technologies).
Results: :
OCT reflectivity maps of the IS/OS displayed the areas of photoreceptor dysfunction that correlate well with retinal sensitivity assessed by microperimetric examination.
Conclusions: :
Subtle changes in the IS/OS reflectivity can be detected and presented as OCT reflectivity maps. The maps reveal the areas of photoreceptor dysfunction and can be correlated with functional changes shown by microperimetry. We believe that the use of 3-D analysis of segmented IS/OS in larger number of retinal pathologies may help in better understanding of photoreceptor dysfunction and allow for more accurate interpretation of the IS/OS junction layer on OCT cross-sectional images.
Keywords: photoreceptors • imaging/image analysis: clinical • retina