Abstract
Purpose: :
To evaluate retinal thickness using SD-OCT in vivo imaging in canine models of outer retinal disease
Methods: :
Four models (n=3/group) were chosen at advanced stages of disease and compared to normal controls (n=6): (1) fast progressing rod cone dysplasia 1 (rcd1); (2) slow progressive rod-cone degeneration (prcd); (3) CNGB3 achromatopsia; and (4) Leber congenital amaurosis (RPE65-LCA. High resolution SD-OCT images from both eyes were acquired along the 0° temporal line from the optic nerve head as well as 45° superior to this line to include a portion of the area centralis or surrounding regions. Images were analyzed to measure full and inner retinal thicknesses (in µm) temporally from the optic nerve head. The combined thicknesses of inner plexiform, ganglion cell, and nerve fiber layers made up inner retinal thickness. Thicknesses in four models were compared to normal controls by multivariate analysis and adjusted for age and gender.
Results: :
The mean (±SE) full retinal thickness in normal adult dogs was 225±5µm at the 0° line and 233±4µm at the 45° line. Inner retinal thickness measurements were 77±5µm and 76±3µm respectively. There was a significant decrease in the mean full retinal thickness in dogs with rcd1 (189±3µm), prcd (168±6µm) and LCA (204±7µm) at the 0° line, but only rcd1(205±7µm) and prcd (156±7µm) at the 45° line. In general, inner retinal thickness measurements remained unchanged with disease, except for a significant increase in inner retinal thickness measurement with rcd1.
Conclusions: :
These data confirm some known trends in canine models of outer retinal disease, such as full retinal thinning which was most significant in rcd1 and prcd, less obvious in RPE65-LCA, and non-existent with achromatopsia. Inner retinal thicknesses were well preserved which bauds well for potential therapy. It remains to be shown if the increased inner retinal thickness in rcd1 is real or represents a technical artifact.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: non-clinical • retina