Source: http://www.healio.com/optometry/glaucoma/news/online/{afd08961-1802-4c8f-a7ef-807e8980c396}/obstructive-sleep-apnea-associated-with-decreased-retinal-nerve-fiber-layer-thickness

Zhao XJ, et al.J Glaucoma. 2016; doi:10.1097/IJG.0000000000000349.

Patients with sleep apnea may have an increased risk for loss of retinal nerve fiber layer thickness, according to a study.

Researchers from Sun Yat-sen University in Zhuhai, China, performed a meta-analysis of six studies involving 1,034 eyes between 2011 and 2014. All the studies evaluated one or more of the following: mean retinal nerve fiber layer (RNFL) thickness; four-quadrant (superior, nasal, inferior and temporal) RNFL thickness; RNFL thickness according to stage of obstructive sleep apnea syndrome (OSAS).

Patients excluded from the study were those with a history, suspicion or verification of glaucoma, optic neuritis, chronic uveitis, retinitis pigmentosa, ocular trauma, previous ocular surgery, multiple sclerosis, Parkinson’s disease or stroke, the study said.

The combined mean difference of RNFL thickness was –2.05 μm with no heterogeneity in mild OSAS, –2.49 μm with no heterogeneity in moderate OSAS and –6.36 μm with significant heterogeneity in severe OSA (P < .003).

The combined mean difference in RNFL thickness was –1.83 μm with no heterogeneity in the superior quadrant, –2.32 μm with no heterogeneity in the nasal quadrant, –3.31 μm with no heterogeneity in the inferior quadrant and –0.75 μm with no heterogeneity in the temporal quadrant.

"We have reason to believe that OSAS can cause glaucoma by cutting down oxygen supply, increasing the IOP, aggravating [visual field] defect and reducing RNFL, etc. To establish a potential causal relationship between OSAS and RNFL thickness, further large-scale, long-term prospective studies need to be performed,” the researchers wrote. — by Nhu Te