Retinal Nerve Fiber Layer Thickness Measurements in Patients With Sleep Apnea Syndrome

An association between glaucoma and OSAHS has been reported in several studies. Glaucoma is a progressive optic neuropathy involving loss of retinal ganglion cells and their axons at the level of the optic nerve head.Computerized technologies have now been successfully used in evaluating retinal nerve fiber layer (RNFL) thickness in glaucoma.Given the evidence of a possible link between OSAHS and glaucoma, it is reasonable that structural losses in retinal nerve fiber layer (RNFL) thickness would be present in OSAHS.Indeed,decreased retinal nerve fiber layers was found in patients with OSAHS, the severity of which correlated with the severity of the patients' OSAHS using scanning laser Polarimetry (SLP).Optical coherence tomography (OCT) provides quantitative RNFL thickness data by measuring the difference in the temporal delay of back-scattered light from the RNFL and a reference mirror.During the past decade, OCT has been used widely in clinical practice to discriminate glaucomatous eyes and eyes with early perimetric glaucoma from normal eyes. Several studies confirmed the accuracy and reproducibility of the RNFL thickness measurements by OCT. The thickness of the peripapillary RNFL was measured with the Stratus OCT(Carl Zeiss Meditec, Inc, Dublin,CA)using the fast scan protocol(3.4).Only good quality images, as judged by the well-focused and centered scans,no artifacts showing distorted anatomy, no missing parts and a signal strength ≥6, were used for further analysis. The considered OCT parameters were overall average RNFL thickness and the average RNFL thickness in 4 quadrants (superior, nasal,inferior,and temporal)extracted from the standard RNFL thickness analysis report(RNFL Thickness Average Analysis Protocol).

Inclusion criteria

• formal diagnosis of moderate or severe OSAHS
• eligibility to sign informed consent form
• older than 18 years

Exclusion criteria

• known glaucoma
• not eligible to sign informed consent form
• younger than 18 years
• incompetent persons who lack decision making capability