Summary: Losing a single hour of sleep during the spring transition to DST corresponds to an up to 30% increased risk of developing major retinal vascular conditions, including proliferative diabetic retinopathy and neovascular age-related macular degeneration, within the following month.
Conversely, gaining an hour of sleep during the fall return to standard time appears protective, correlating with a 20% to 40% reduction in disease risk. Because the retina is one of the most metabolically demanding tissues in the human body, these findings highlight how systemic circadian misalignment, inflammatory cascades, and microvascular stress directly endanger vision.
Key Facts
- Spring DST Transition Triggers Risk Spikes: In the 30 days following the spring transition to daylight saving time (losing 1 hour of sleep), patients exhibited a 20% to 30% increase in new diagnoses of proliferative diabetic retinopathy (PDR) and neovascular age-related macular degeneration (nAMD).
- Fall Standard Time Shift Shows Protective Effect: Gaining 1 hour of sleep during the autumn transition back to standard time was associated with a 20% to 40% lower risk across all four evaluated conditions (RAO, RVO, PDR, and nAMD) compared to baseline control periods (January and July).
- The Retinal Microvasculature Susceptibility: The retina features one of the highest metabolic rates and most dense microvascular networks in the human body. Circadian misalignment triggers acute systemic inflammatory responses and metabolic derangements that compromise these fragile retinal vessels.
- Public Health & Clinical Implications: The findings coincide with ongoing legislative debates over making daylight saving time permanent in the United States, providing empirical evidence that abrupt 1-hour time shifts carry measurable ocular vascular consequences.
Source: Northwestern University
For the first time, Northwestern Medicine scientists have detailed how the semiannual clock changes impact a person’s risk of developing retinal vascular disease, a group of disorders that affect blood vessels in the retina and can lead to vision loss.
The findings were published last month in Scientific Reports, a Nature Portfolio journal.
The nationwide analysis of more than 18 million patients found an up to 30% higher risk of developing retinal vascular disease in the month following the transition to daylight saving time in the spring, and a 20% lower risk of disease in the month following the transition back to standard time in the fall.
“Our study suggests gaining an hour of sleep may be protective against disease risk,” said study lead author Dr. Rukhsana Mirza, professor of ophthalmology and medical education at Northwestern University Feinberg School of Medicine. “Even one hour of change can impact a patient’s health and perhaps patients who are reporting new symptoms in the period after a change in time, specifically in the spring, may warrant closer evaluation.”
The findings come as the U.S. House of Representatives passed a measure this week to make daylight saving time permanent. The fate of the measure in the Senate is uncertain.
Seasonal clock changes have been shown to cause disruptions in circadian rhythm, the body’s 24-hour internal clock that regulates the sleep-wake cycle, hormone production and body temperature, among other essential bodily functions. The retina — the innermost, light-sensitive layer of tissue in the eye — provides a “window to the body” and plays an important role in circadian rhythm, Mirza said.
Recent studies have shown an association between seasonal clock changes, which can result in disrupted sleep, and increased risk of acute cardiovascular events, including stroke.
“We have seen how daylight saving time transitions, particularly the spring transition when we lose an hour of sleep, are associated with increased rates of heart attack and stroke. This led us to ask if these similar effects would be happening in the retina, which is one of the most metabolically active tissues in the body and contains some of the body’s most complex microvascular networks,” Mirza said.
The findings
To understand how circadian disruption impacts eye health, Mirza’s team analyzed health insurance claims data from more than 18 million patients aged 18 to 64 years who were newly diagnosed with retinal vascular disease. Patients were enrolled in the Merative MarketScan Commercial Database between 2012 and 2014.
The Northwestern scientists calculated the incidence of new diagnoses of four retinal vascular diseases in the month following the spring and fall clock changes and during two control periods in January and July. The conditions included retinal artery and vein occlusions, proliferative diabetic retinopathy and neovascular age-related macular degeneration.
The research team then compared disease risk during the week and month following each seasonal clock change.
They found that:
- The month following the spring transition to daylight saving time (when Americans lose an hour of sleep) was associated with a roughly 20-30% higher risk of proliferative diabetic retinopathy and neovascular age-related macular degeneration
- Patients had a roughly 20-40% lower risk of retinal artery occlusion, retinal vein occlusion, proliferative diabetic retinopathy and neovascular age-related macular degeneration in the month following the fall return to standard time
“I think that relationship was pretty interesting, and it makes a lot of sense. There’s been literature showing that losing an hour’s sleep and circadian misalignment can cause inflammatory responses and metabolic derangements, and there’s also been some literature suggesting that getting an hour’s sleep in the context of daylight saving might be protective,” said Dr. Kyle Chan, a resident physician in the department of ophthalmology at Feinberg and co-first author of the study.
Chan also noted limitations of their study include having access to only three years’ worth of patient data but that he hopes future work will replicate their findings using other larger databases.
“In the future, we’d love to see if other groups can replicate our findings in non-overlapping databases, for example those in the academic setting, or look at more years of data as well to see if these findings hold true,” Chan said.
The investigators also hope the findings will prompt future studies to investigate the impact of daylight saving transitions and sleep disturbances on a more patient level. “I think this really opens up new opportunities of collaboration between ophthalmology, neurology, sleep medicine, cardiovascular medicine … really exciting possibilities to understand the whole person,” Mirza said.
This study is titled, “Daylight saving time transition and new-onset retinal vascular disease: a nationwide cohort study.” It was supported by an unrestricted departmental grant from Research to Prevent Blindness and Merative MarketScan Dissertation Support Program by access to the MarketScan research database.
Key Questions Answered:
A: The retina is one of the most metabolically active tissues in the entire human body, requiring a continuous, precise supply of oxygen and nutrients through a dense network of tiny blood vessels (microvasculature). Sudden daylight saving time shifts disrupt circadian rhythm, the body’s internal 24-hour clock. Losing even one hour of sleep causes immediate circadian misalignment, triggering systemic inflammation, elevated blood pressure, and metabolic stress that strain these sensitive ocular micro-vessels.
A: The Northwestern study evaluated four primary retinal vascular disorders:
Proliferative Diabetic Retinopathy (PDR): Advanced diabetic eye disease marked by abnormal, fragile blood vessel growth.
Neovascular Age-Related Macular Degeneration (nAMD): “Wet” AMD, where abnormal vessels leak fluid into the center of vision.
Retinal Artery Occlusion (RAO): A blockage in the retinal arteries (essentially an eye stroke).
Retinal Vein Occlusion (RVO): A blockage in the veins draining blood from the retina.
A: Cardiology and neurology studies have long documented an uptick in acute cardiovascular events, such as heart attacks and ischemic strokes, during the days following the spring time change. Because the retinal blood vessels reflect systemic vascular health, serving as a literal “window to the body”, Northwestern researchers confirmed that the micro-vessels in the eye suffer from the exact same circadian and inflammatory stress as the larger arteries in the heart and brain.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this visual neuroscience research news
Author: Ben Schamisso
Source: Northwestern University
Contact: Ben Schamisso – Northwestern University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Daylight saving time transition and new-onset retinal vascular disease: a nationwide cohort study” by Kyle S. Chan, Brian T. Cheng, Margaret M. Banker, Phyllis C. Zee & Rukhsana G. Mirza. Scientific Reports
DOI:10.1038/s41598-026-55281-7
Abstract
Daylight saving time transition and new-onset retinal vascular disease: a nationwide cohort study
Daylight saving time (DST) transitions lead to disruptions in circadian rhythm, and studies have identified an association between DST transitions and cardiovascular events. Changes in retinal microvasculature can reflect systemic cardiovascular health.
This study investigated the relationship between DST transitions and retinal vascular disease. Patients aged 18–64 years old enrolled in the Merative MarketScan Commercial Database between 2012 and 2014 were identified. Incidence of new diagnosis of retinal artery occlusion (RAO), retinal vein occlusion (RVO), proliferative diabetic retinopathy (PDR), and neovascular age-related macular degeneration (nvAMD) were determined after autumn DST transition, spring DST transition, and a summer or winter control period.
Survival analysis via Kaplan Meier curves and Cox proportional hazards models were used to determine the effect of variables of interest on new-onset retinal vascular disease during one-week and one-month periods following DST transition. We identified 12,640,343 patients who met inclusion criteria. With a summer control period, there was lower risk of RVO (adjusted hazard ratio [98.75% confidence interval]: 0.84 [0.72–0.99], P = 0.033), and PDR (0.83 [0.73–0.94], P = 0.001) in the month following autumn DST transition.
There was higher risk of PDR (1.34 [1.19–1.50], P<0.0001) and nvAMD (1.24 [1.03–1.50], P = 0.015) in the month following spring DST transition. With a winter control period, there was lower risk of RAO (0.75 [0.60–0.94], P = 0.005), RVO (0.66 [0.53–0.82], P<0.0001), PDR (0.61 [0.51–0.72], P<0.0001), and nvAMD (0.64 [0.49–0.83], P < 0.0001) in the month following autumn DST transition. Further investigation into the effects of circadian disruption on ocular health is warranted.
