Retinal pathology detected by optical coherence tomography in an animal model of Parkinson's disease.

Abstract

BACKGROUND: Optical coherence tomography (OCT) is a noninvasive procedure for analysis of retinal morphology. Significant changes in the thickness of the peripapillary retinal nerve fiber layer (RNFL) in Parkinson's disease (PD) have been reported, and the current study was performed to examine whether such changes can also be detected in an animal model of PD. METHODS: Optical coherence tomography measurements of peripapillary RNFL thickness, macula volume, and foveal thickness were obtained from 10 normal and five 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated cynomolgus monkeys with stable Parkinsonian signs. RESULTS: Average RNFL thickness was significantly decreased in Parkinsonian monkeys compared with controls, with statistically significant RNFL thinning found in nasal and inferior quadrants. Macula volume and foveal thickness were also significantly reduced in Parkinsonian animals compared with controls. CONCLUSIONS: As described in PD, RNFL thinning, reduced macula volume, and reduced foveal thickness also occurs in monkeys with MPTP-induced Parkinsonism. These findings pave the way for additional studies in which OCT may be used to track changes in the retina that might be present very early in the PD pathological process, perhaps preceding the onset of motor signs.