Abstract
Purpose: :
To test whether sleep position correlates with visual field asymmetry in low pressure (LPG) and high pressure (HPG) open angle glaucoma. LPG patients have more frequent asymmetric visual field loss and a predominance of left sided loss when compared with HPG patients, but no asymmetric risk factors have been identified to this date.
Methods: :
50 LPG and 178 HPG patients were identified via chart review and the visual field index (VFI) was calculated for the most recent reliable exam with the Humphrey Visual Field Analyzer II-i with Guided Progression Analysis. The retinal nerve fiber layer (RNFL) measures (average RNFL thickness and RFNL symmetry) were obtained from the most recent OCT Cirrus exam. Applying the Low Pressure Glaucoma Treatment Study Group (LoTGS) criteria, an untreated pressure of less than 22 mmHg was defined as LPG. Participants completed a survey about their sleep position which characterized their position as predominantly side, prone, supine or unknown. Patients who chose side as their primary position were further characterized as sleeping mostly on the right side (n=71), left side (n=59) or both sides (n=47). The Mann-Whitney test was applied.
Results: :
Right sided sleepers had a significantly larger VFI difference (right VFI - left VFI) (17.06 vs 10.85, p=0.009) and a lower right RNFL thickness (68.94 vs 75.81, p=0.005) than left sided sleepers. When compared to all non-right sided sleepers, right sided sleepers also had a larger VFI difference (17.06 vs 12.80, p=0.021), lower right RFNL thickness (68.94 vs 74.97, p=0.003) and lower RFNL symmetry (53.73 vs 62.29, p=0.039). In the subgroup analysis, HPG patients with right dominant sleep position had a greater VFI difference (16.20 vs 12.48, p=0.052) and lower right RFNL thickness (68.64 vs 75.46, p=0.003) than non-right sided sleepers. The same trend was seen among right sided sleepers versus left sided sleepers respectively (15.98 vs 11.23, p=0.054 and 69.31 vs 77.48, p=0.02). Among LPG patients, right sided sleepers had a greater VFI difference than left sided sleepers (19.21 vs 9.27, p = 0.030). Also right sided sleepers had a lower RNFL symmetry than non-right sided sleepers (45.33 vs 63.34, p=0.025).
Conclusions: :
Right sided sleeping is related to a greater VFI and RNFL asymmetry in LPG and HPG.
Keywords: visual fields • nerve fiber layer • clinical (human) or epidemiologic studies: risk factor assessment