Association between obstructive sleep apnea hypopnea syndrome and normal tension glaucoma

Abstract

Background and objective: To study the prevalence of glaucoma among a group of patients with obstructive sleep apnea hypopnea syndrome and to test the hypothesis that OSAS should be considered as a significant risk factor for normal tension glaucoma (NTG). Subjects and methods: The study included forty subjects recently confirmed to have OSA and fifteen obese subjects without OSAHS as control group. Control subjects were matched to patients regarding coexisting comorbid conditions. All patients were planned for full polysomnographic study, and a complete ophthalmologic examination within 48 h of the PSG. Results: Glaucoma was diagnosed in fourteen (14) out of 40 patients with OSAHS yielding an estimate prevalence of 35% among patients with OSAHS compared to only one case of glaucoma in obese patients without OSAHS that is to say 6.7% with statistically significantly difference between the two groups (χ2 = 4.415, p = 0.045). We found that mean ± SD CD ratio was statistically significantly higher in patients with OSAHS compared to controls without OSAHS as follows: 0.40 (0.20–0.80), and 0.30 (0.20–0.60) respectively (Z = 2.435∗, p = 0.015). Comparing subgroup of patients: with glaucoma (n = 14) to those without glaucoma (n = 26), statistically significantly higher CD ratio 0.70 (0.60–0.80) was noted in those with glaucoma compared to those without glaucoma 0.30 (0.20–0.40) (Z = 5.292∗, p = 0.001). Statistically a significantly positive correlation existed between CD ratio and AHI in patients with OSAHS with r = 0.566 at p < 0.001 as well as both subgroups with and without glaucoma with r = 0.902, 0.638 respectively at p < 0.001. Statistically significantly positive correlation existed between CD ratio and DI in patients with OSAHS with r = 0.622 at p < 0.001 as well as both subgroups with and without glaucoma with r = 0.847, 0.678 respectively at p < 0.001. Statistically significantly negative correlation existed between CD ratio and lowest SaO2 during sleep in patients with OSAHS with r = −0.561 at p < 0.001 as well as both subgroups with and finding of a higher than expected prevalence of glaucoma in our patient population with sleep apnea suggests that clinicians may need to consider the possibility that unrecognized glaucoma is present in patients with newly diagnosed or existing sleep apnea. In conclusion, OSAS should be considered as a significant risk factor for NTG. So it is advisable to take an accurate sleep history (including questions about snoring, nocturnal gasping-choking, daytime sleepiness and morning headaches) from patients with NTG and refer these patients for PSG test and nCPAP therapy.

Keywords

• Normal tension glaucoma
• Obstructive sleep apnea hypopnea syndrome
• Apnea hypopnea index
• Cup to disk ratio
• Intraocular pressure
• Visual field defects