Behind the headlines: Could poor sleep make you go blind?
Key Takeaways
A large observational study based on self-reported data has found a link between poor sleep patterns and an increased risk of glaucoma, but the relationship is unclear.
While this study adds further observational evidence of a link between poor sleep and glaucoma, other factors like age, smoking, high blood pressure, and diabetes have more clear connections to glaucoma development.
A widely reported study has linked poor sleep patterns with an increased risk of glaucoma, which can lead to blindness. But should the risk of going blind from a lack of sleep keep you up at night?
Reporting on a study into the connection between sleep patterns and glaucoma, The Independent warned that a "lack of sleep could make you go blind".
The article, reporting on a large prospective cohort study published in BMJ Open, claimed that "too much or too little shut-eye can increase the risk of developing glaucoma".[]
In the observational study, researchers found that patients with insomnia, snoring, daytime tiredness or unusual sleep patterns had a higher chance of developing glaucoma.[]
With over 400,000 subjects monitored over a 10-year period, it is a large study and so the connection between sleep disturbance and glaucoma may seem worrying. But are the concerns justified?
The research
The study asked about the sleep habits of 409,053 participants from the UK Biobank, a large-scale biomedical database, aged 40-69 without glaucoma between 2006-10.[] Over the next decade, researchers identified 8,690 glaucoma cases.
Researchers collected self-reported data on five sleep behaviors – sleep duration, chronotype, insomnia symptoms, daytime sleepiness and snoring. Researchers tracked participants until March 2021, examining sleep patterns using cluster analyses and excluding potential confounders such as lifestyle, comorbidities and sociodemographic factors.
Participants who slept more or less than a 7 to 9-hour period were 8% more likely to develop glaucoma (2.19 vs 1.90 cases per 1,000 person-years), while those who were often sleepy during the day were 20% more likely (2.76 to 1.84). Reported insomniacs had a 12% greater risk (2.29 to 1.88) and snoring meant a 4% greater risk (2.07 to 1.95).
The study accounted for other factors such as sex, ethnicity, BMI, smoking or hypertension.
Purely observational
The observational nature of the study limits our understanding of any potential link between sleep and glaucoma. It’s impossible to tell whether sleep patterns affect glaucoma risk, or the other way around.
Furthermore, sleep behavior was self-reported; participants completed a questionnaire at recruitment and there were no objective measurements taken. Questions included whether the participant considered themselves a morning or evening person, if they had trouble sleeping at night, or found themselves sleepy during the day.
These questionnaires were not repeated, so any changes in sleep patterns over the course of a decade were not known. Outcomes and glaucoma diagnoses were obtained through medical records. The researchers acknowledged the need for repeated and objective measurements of sleep behaviors to validate their findings.
Unclear connections
As an observational study, the research doesn’t shed light on any biological mechanism that could link sleep quality and glaucoma. In general, the underlying causes of glaucoma are still not fully understood, which makes it more difficult to understand the exact connection between the condition, its progression and sleep quality.
The researchers proposed several theories: elevated intraocular pressure while lying down, problems with oxygen intake, or imbalanced sleep hormones which damage the nerve in the eye could all be possible factors. However, the researchers acknowledge that glaucoma itself could influence sleep patterns.
The connection between poor sleep and glaucoma is not a new realization; the impact of sleep apnea, sleeping position, sleep disturbances and daytime drowsiness have all been investigated before.[] Though this study adds further observational evidence of a link, its nature remains unclear.
Other factors like age, smoking, high blood pressure and diabetes have been more clearly connected to development of glaucoma.[] Therefore, these risk factors warrant greater focus as preventive steps than ‘poor sleep’ at present.[]