Summary: A new study has linked moderate-to-severe obstructive sleep apnea (OSA), characterized by low oxygen levels overnight, with an increased risk of developing wet age-related macular degeneration (AMD). The research suggests nocturnal hypoxia could affect the oxygen-sensitive retina, contributing to AMD progression.
Conducted with 225 participants using home-based oximeters, the study found that treating OSA might reduce the risk of AMD. Researchers aim to validate these findings and explore whether managing sleep apnea can slow vision loss in at-risk individuals.
Key Facts:
- Moderate-to-severe OSA is linked to increased risk of wet AMD.
- Nocturnal hypoxia may harm the retina, which has high oxygen demands at night.
- Treating OSA could potentially reduce the risk of developing wet AMD.
Source: Centre for Eye Research Australia
A Center for Eye Research Australia study has linked low levels of oxygen in the blood overnight—a common sign of obstructive sleep apnea—with wet age-related macular degeneration.
The findings, published in Clinical and Experimental Ophthalmology, suggest obstructive sleep apnea (OSA) could be a modifiable risk factor associated with the “wet” form of late-stage age-related macular degeneration (AMD).
University of Melbourne Master’s student Attiqa Chaudhary along with members of the CERA’s Macular Research unit, led by Professor Robyn Guymer AM, conducted the study. They also worked with sleep disorder expert Professor Matthew Naughton from Monash University to analyze the results.
The team conducted a sleep study involving 225 participants aged over 50 with different stages of AMD and measured their oxygen levels over three nights with a home-based finger oximeter. Their level of OSA was calculated based on the oxygen levels in their blood overnight.
The results showed that moderate-to-severe OSA, which results in lower levels of oxygen in the blood overnight, was associated with an increased risk of having wet AMD compared to those without OSA.
Study co-supervisor Dr. Carla Abbott says the findings are something clinicians should be aware of.
“Like AMD, sleep apnea mainly affects people over the age of 50 and many people don’t realize they have it,” Dr. Abbott says.
“If this association is validated it may well be worth asking people with high-risk early stages of AMD if they have any symptoms suggestive of OSA, as treating OSA might reduce the risk of developing wet AMD.”
Nocturnal hypoxia and wet AMD
Nocturnal hypoxia often occurs as a result of OSA, where a person’s airway becomes blocked or narrowed overnight, reducing their oxygen intake.
A lack of oxygen overnight can cause various health issues over time, but the light-sensitive retina in the eye may be particularly sensitive to small drops in oxygen levels.
“The retina is very active at night—it has its highest need for energy while it recovers from the day,” says Dr. Abbott.
Many people diagnosed with sleep apnea use a CPAP device at night, which helps them breathe easier by providing a constant flow of air through a mask.
“If people aren’t currently getting treatment, it’s putting them at risk over years of not sleeping properly and having low oxygen at night, which could be a contributing factor to AMD, in particular wet AMD,” says Dr. Abbott.
Currently known risk factors for AMD include smoking status, diet, age and genetics.
Dr. Abbott says the team will need to conduct larger studies to better understand this association and, if validated, will explore whether treating sleep apnea has a clinically meaningful impact on reducing progression to wet AMD.
The work is part of the wider Synergy High Risk AMD Study, which is investigating AMD and the potential underlying causes that make some people more likely to lose their vision.
About this visual neuroscience research news
Author: Carla Abbott
Source: Centre for Eye Research Australia
Contact: Carla Abbott – Centre for Eye Research Australia
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Nocturnal hypoxia and age‐related macular degeneration” by Attiqa Chaudhary et al. Clinical and Experimental Ophthalmology
Abstract
Nocturnal hypoxia and age‐related macular degeneration
Background
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).
Methods
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.
Results
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).
Conclusions
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.
