Session Title: Free Paper Session 25: Imaging IV
Session Date/Time: Sunday 10/09/2017 | 10:00-11:30
Paper Time: 10:30
Venue: Room 113
First Author: : K.Sharma INDIA
Co Author(s): : A. Lenka R. Shetty N. Yadav A. Mohan
To investigate the association of retinal structural (peripapillary retinal nerve fiber layer (PRNFL) and macular thickness) and functional parameters (vascular oxygen saturation) with clinical scores and medication dosage in patients with Parkinson’s disease.
Tertiary Care Eye Hospital in South India
A cross sectional observational study of 22 eyes of 11 MRI confirmed patients with Parkinson’s Disease on treatment was undertaken. They underwent a neurological evaluation including the Unified Parkinson’s disease rating scale (UPDRS III) and Hoehn and Yahr scale (H&Y) and the dose of Levodopa was specifically documented. A comprehensive ophthalmic examination was done. Patients with corrected distance visual acuity less than 6/9, any eye disease like cataract, glaucoma, retinopathy, uveitis were excluded. They then underwent two additional tests – optical coherence tomography to measure PRNFL and macular thickness (Spectralis, Heidelberg, Germany) and retinal oximetry (Oxymap T1, Oxymap HF, Reykjavik, Iceland). Their RNFL thickness, arteriolar and venous saturations and diameter; and arterio-venous saturation difference (AVSD) were recorded and statistical analysis was performed to study significant associations.
The average age of the patients was 56.2 years (95% CI – 53.4-59.0), age of onset of disease was 50.8 years (95% CI – 47.7-53.9), duration of disease was 5.1 years (95% CI – 3.7-6.5), UPDRS III score was 27.9 (95% CI – 25.1-30.7), H&Y score was 2.2 (95% CI – 2.1-2.4) and Levodopa equivalent dosage per day was 626(95% CI - 532.8-719.2). The PRNFL thickness was 103.8 µm (95% CI – 100.3-107.3) and macular thickness was 274.1 µm (95% CI – 263.8-284.4). The arterial saturation was 97.5% (95% CI – 94.3-100.9), venous saturation 60.1% (95% CI – 58.2-61.9), AVSD was 37.5% (95% CI – 34.4-40.6), arteriolar diameter was 113.3 µm (95% CI – 107.9-118.7), venous diameter 152.4 µm (95% CI – 147.7-157.1). The H&Y score correlated negatively with the age of onset (r=-0.459, p=0.048), positively with the UPDRS score (r=0.623,p=0.002), and Levodopa dosage (r=0.671,p=0.001). The arteriolar saturation correlated inversely with Levodopa dosage (r=0.554,p=0.011) while positively with AVSD (r=0.840,p<0.001). The RNFL thickness did not show any significant associations with any of the other parameters.
Retinal metabolic parameters like arteriolar saturation and AVSD showed a significant correlation with Levodopa dosage. This may imply that retinal oximetry changes occur in association with underlying central nervous system derangements. Further studies with larger sample sizes may help to establish retinal oximetry as an indirect biomarker for neurodegenerative diseases.