Bahr and colleagues have prospectively evaluated the relationship between various glaucoma phenotypes (primary open-angle, normal tension, ocular hypertension and healthy controls) and obstructive sleep apnea (OSA). Over 100 subjects underwent home sleep apnea testing. Among the full cohort, no significant correlation was seen between glaucoma parameters (such as IOP or visual field mean deviation) and apnea parameters (such as the apnea hypoxia index). Interestingly, mean values of all apnea parameters differed significantly between patients with POAG and NTG, with more severe apnea indicators in POAG than in NTG. For instance, the AHI (which is the number of apneic/hypoxic episodes per hour) was much higher in POAG than NTG patients. Similar results were obtained in comparing OHT patients to NTG patients. Their observation that AHI was higher in eyes with high IOP but that AHI did not correlate with IOP suggests a possible different pathophysiology of glaucoma in high- and low-IOP eyes. Perhaps, the authors speculate, OSA (particularly in its severe form) may raise IOP and may thus play a meaningful role in the pathophysiology of high-IOP glaucoma but not low-IOP glaucoma. They further speculate that systemic inflammation - which has been reported in both OSA and high-IOP glaucoma - may be part of the link between these two conditions. Further study is needed to better clarify the relationship between glaucoma and OSA.
OSA (particularly in its severe form) may raise IOP and may thus play a meaningful role in the pathophysiology of high-IOP glaucoma but not low-IOP glaucoma