Abstract
Purpose: :
The retinal dysplasia and degeneration (rdd) chicken has a progressive retinal degeneration leading to blindness by 10 weeks, due to a mutation in the known CRB1 interactant, MPDZ/MUPP1. Standard histopathology of enucleated eyes has shown a gradual thinning of all the retinal layers and buckling of the retina, similar to that seen with CRB1 mutations. The aim of this study was to investigate the in vivo retinal architecture in rdd birds and to illustrate the utility of optical coherence tomography (OCT) as a tool for assessing retinal degeneration in vivo in chicken models of human retinal dystrophy.
Methods: :
Horizontal line spectral domain OCT was performed through undilated pupils using the SPECTRALIS OCT. Images were collected from both eyes of live 1 day-old and 12 month-old rdd birds and age-matched controls.
Results: :
For the images captured from the control wild-type (White Leghorn) birds, normal retinal lamination was observed and the photoreceptor outer segments could be resolved. Mean retinal thickness was 251µm (SD = 9µm, range 229µm - 264µm, n = 6) and 280µm (SD = 11µm, range 246µm - 298µm, n = 6) in the 1 day-old and 12 month-old birds respectively. However, in images captured from both 1 day-old and 12 month-old rdd birds, the outer retinal layers were absent. Mean retinal thickness was 202µm (SD = 8µm, range 191µm - 220µm, n = 6) and 154µm (SD = 18µm, range 113µm - 184µm, n = 6) respectively.
Conclusions: :
Our in vivo measurements in rdd birds support previous observations using standard histopathology of the eyes which demonstrate a gradual thinning of the retina and loss of the outer retinal architecture. Spectral domain OCT will be a valuable tool in monitoring thickness as well as structure of the retina during targeted therapy of this and other animal models of inherited blindness.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • imaging/image analysis: non-clinical