Introduction: This study was designed to explore the relationship
between retinal nerve fiber layer (RNFL) thickness and cognition in
Idiopathic Parkinson’s disease (IPD) patients without visual symptoms or
diagnosis of dementia.
Methods: Groups of patients with idiopathic Parkinson’s disease
and healthy controls were compared ophthalmologically using
optical coherence tomography (OCT) and cognitively through
neuropsychological tests.
Results: The findings highlighted a pronounced RNFL thinning,
especially in the right nasal inferior quadrant of IPD patients compared
to the control group. Almost half (47%) of the subjects in the IPD group
exhibited issues in one or multiple subcomponents of Addenbrooke’s
Cognitive Examination-Revised (ACE-R). At the same time, the study
suggested that effects in the visuospatial domain may be associated
with disease severity in IPD patients. However, the investigation could
not establish a direct association between the severity or duration of the
disease and OCT measurements. A correlation was observed between
certain ACE-R scores and some RNFL quadrants.
Conclusion: In conclusion, the inception phases of IPD are characterized
by discernable visual pathologies and cognitive anomalies. The thinning
of the RNFL, which can be identified through OCT, might serve as a
pivotal tool for tracking the early progression of IPD and formulating
intervention strategies. That being said, more comprehensive studies
are essential to wholly understand OCT’s role in the early diagnosis and
monitoring of IPD.
Keywords: Cognition, Idiopathic Parkinson’s disease, optical coherence
tomography, retinal nerve fiber layer.