Decreased retinal nerve fiber layer thickness in patients with obstructive sleep apnea/hypopnea syndrome

To compare parameters for retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) measurements, and macular thickness in patients with different severities of obstructive sleep apnea/hypopnea syndrome (OSAHS) versus normal controls.

Patients presenting with snoring and daytime sleepiness who underwent overnight polysomnography to determine OSAHS severity were recruited, and subsequently referred for ophthalmologic evaluation. Optical coherence tomography was used to evaluate the retinal nerve fiber layer (RNFL), optic nerve head topography, and macular thickness for early detection of glaucoma. Patients determined not to have OSAHS were included as controls.

A total of 127 subjects were recruited, including 105 patients with OSAHS and 22 normal control subjects. RNFL thickness was significantly lower for the severe OSAHS group than for the control and mild OSAHS groups in the average (p < 0.0001) and in the superior quadrant (p = 0.0007). When subjects without OSAHS or with mild disease (AHI < 15) were grouped together and compared with patients with moderate/severe OSAHS (AHI ≧ 15), RNFL thickness measurements for the latter group were significantly lower in the average (p < 0.0001), and in the superior (p = 0.001), inferior (p = 0.029), and temporal (p = 0.007) quadrants. Positive correlations were identified between lowest oxygenation saturation on PSG and RNFL thickness in the average (r = 0.260), superior (r = 0.200) and nasal (r = 0.156) quadrants.

Compared to patients without OSAHS or those with mild disease, RNFL thickness was lower in patients with moderate/severe OSAHS. Lowest saturation of oxygen in the moderate/severe OSAHS group correlated with decreased RNFL thickness. Patients with moderate and severe OSAHS are at increased risk for glaucoma.