Nocturnal hypoxia and age-related macular degeneration

Nocturnal hypoxia is common, under-diagnosed and is found in the same demographic at risk of age-related macular degeneration (AMD). The objective of this study was to determine any association between nocturnal hypoxia and AMD, its severity, and the high-risk sub-phenotype of reticular pseudodrusen (RPD).

This cross-sectional study included participants aged ≥50 years with AMD, or normal controls, exclusive of those on treatment for obstructive sleep apnoea. All participants had at home, overnight (up to 3 nights) pulse oximetry recordings and multimodal imaging to classify AMD. Classification of Obstructive Sleep Apnea (OSA) was determined based on oxygen desaturation index [ODI] with mild having values of 5-15 and moderate-to-severe >15.

A total of 225 participants were included with 76% having AMD, of which 42% had coexistent RPD. Of the AMD participants, 53% had early/intermediate AMD, 30% had geographic atrophy (GA) and 17% had neovascular AMD (nAMD). Overall, mild or moderate-to-severe OSAwas not associated with an increased odds of having AMD nor AMD with RPD (p ≥ 0.180). However, moderate-to-severe OSA was associated with increased odds of having nAMD (odds ratio = 6.35; 95% confidence interval = 1.18 to 34.28; p = 0.032), but not early/intermediate AMD or GA, compared to controls (p ≥ 0.130). Mild OSA was not associated with differences in odds of having AMD of any severity (p ≥ 0.277).

There was an association between nocturnal hypoxia as measured by the ODI and nAMD. Hence, nocturnal hypoxia may be an under-appreciated important modifiable risk factor for nAMD.