Summary: Losing one hour of sleep during the spring daylight saving time (DST) change is associated with up to a 30% higher risk of developing serious retinal vascular conditions—such as proliferative diabetic retinopathy (PDR) and neovascular age-related macular degeneration (nAMD)—within the following month. Conversely, gaining an hour of sleep after the autumn return to standard time appears protective, linked to a 20%–40% reduction in risk. Because the retina is among the body’s most metabolically demanding tissues, these results highlight how circadian disruption, inflammation, and microvascular stress can rapidly affect vision.
Key Facts
- Spring DST Increases Risk: In the 30 days after the spring transition to DST (losing one hour), new diagnoses of PDR and nAMD rose by roughly 20%–30%.
- Fall Shift Appears Protective: In the month following the return to standard time (gaining one hour), the risk of retinal artery occlusion (RAO), retinal vein occlusion (RVO), PDR and nAMD fell by about 20%–40% compared with control periods.
- Retinal Microvasculature Is Vulnerable: The retina’s high metabolic demand and dense microvascular network make it especially sensitive to circadian misalignment, systemic inflammation, and metabolic stress.
- Clinical and Public Health Relevance: These findings provide population-level evidence that abrupt one-hour clock shifts can have measurable ocular vascular consequences—an important consideration amid debates over making DST permanent.
Source: Northwestern University
Overview: For the first time, researchers at Northwestern Medicine have quantified how semiannual clock changes affect the risk of new-onset retinal vascular disease—disorders that damage retinal blood vessels and can lead to vision loss. Their nationwide analysis, published recently in Scientific Reports, used insurance claims to compare incidence around seasonal time changes.
The researchers analyzed data from more than 18 million patients and found a substantial rise in retinal vascular diagnoses in the month after the spring DST transition, and a clear reduction in new diagnoses after the fall return to standard time. These patterns were consistent across several retinal vascular conditions, underscoring a likely connection between short-term sleep loss, circadian disruption, and ocular microvascular health.
“Our study suggests that gaining an hour of sleep may have a protective effect,” said Dr. Rukhsana Mirza, professor of ophthalmology and medical education at Northwestern University Feinberg School of Medicine. “Even a one-hour shift can influence patient health, and people presenting with new visual symptoms shortly after the spring change may warrant closer evaluation.”
Seasonal clock changes are known to disturb circadian rhythm—the body’s 24-hour internal clock that regulates sleep, hormone cycles, and body temperature. Because the retina helps regulate circadian signals and is highly metabolically active, researchers hypothesized it might be particularly sensitive to these disruptions. Previous studies have linked DST transitions to short-term increases in cardiovascular events such as heart attack and stroke; this work extends those observations to the eye’s microvascular system.
Study methods and results: The team used the Merative MarketScan Commercial Database to identify patients aged 18–64 who received a new diagnosis of one of four retinal vascular diseases—retinal artery occlusion (RAO), retinal vein occlusion (RVO), proliferative diabetic retinopathy (PDR), and neovascular age-related macular degeneration (nAMD)—between 2012 and 2014. They compared incidence in the month and week following spring and fall clock changes to two control periods (January and July).
Key findings included:
- About a 20%–30% higher risk of PDR and nAMD in the month after the spring DST transition (losing an hour).
- Approximately 20%–40% lower risk of RAO, RVO, PDR and nAMD in the month after the fall return to standard time (gaining an hour).
Dr. Kyle Chan, co-first author and a resident in ophthalmology at Feinberg, noted the biological plausibility: loss of sleep and circadian misalignment can provoke inflammation, blood pressure changes, and metabolic shifts that strain fragile retinal vessels. He also acknowledged the study’s limitations, including a three-year data window, and encouraged replication using additional databases and longer time spans.
The investigators hope these findings will spark further research at the intersection of ophthalmology, sleep medicine, cardiology and neurology—studies that examine patient-level sleep patterns, circadian biomarkers, and longer-term ocular outcomes to better understand mechanisms and identify preventive strategies.
This research, titled “Daylight saving time transition and new-onset retinal vascular disease: a nationwide cohort study,” was supported in part by Research to Prevent Blindness and by access to the MarketScan research database.
Key Questions Answered:
A: The retina has one of the highest metabolic rates in the body and depends on a finely tuned supply of oxygen and nutrients delivered through dense microvasculature. Sudden DST shifts produce circadian misalignment that can trigger systemic inflammation, transient blood pressure elevation, and metabolic stress—factors that can overload fragile retinal vessels and increase the risk of vascular events.
A: The study focused on four retinal vascular disorders: Proliferative Diabetic Retinopathy (PDR), Neovascular Age-Related Macular Degeneration (nAMD, “wet” AMD), Retinal Artery Occlusion (RAO) and Retinal Vein Occlusion (RVO).
A: Prior cardiology and neurology research has documented increases in acute cardiovascular events, including heart attacks and ischemic strokes, following the spring time change. Because retinal vessels mirror systemic vascular health, this study shows similar short-term vulnerability in the eye’s microvascular networks after circadian disruption.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full by the editorial team.
- Additional context and clarification were added by staff writers.
About this visual neuroscience research news
Author: Ben Schamisso
Source: Northwestern University
Contact: Ben Schamisso – Northwestern University
Image credit: 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. 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 transitions disrupt circadian rhythm, and prior research has linked DST shifts to cardiovascular events. Because retinal microvascular changes reflect systemic vascular health, this study examined whether DST transitions are associated with new-onset retinal vascular disease.
Patients aged 18–64 enrolled in the Merative MarketScan Commercial Database from 2012–2014 were identified and assessed for new diagnoses of RAO, RVO, PDR and nAMD following autumn and spring clock changes, with January and July as control periods. Survival analyses (Kaplan–Meier) and Cox proportional hazards models evaluated risk during one-week and one-month intervals after each transition. The cohort included over 12.6 million eligible patients.
Results showed a lower risk of several retinal vascular conditions in the month after the autumn return to standard time and a higher risk of PDR and nAMD in the month after the spring DST transition. Specifically, with summer and winter control periods, adjusted hazard ratios indicated increased risk of PDR and nvAMD after spring transitions and decreased risk of RAO, RVO, PDR and nvAMD after autumn transitions. The authors conclude that further research is needed to clarify how circadian disruption affects ocular health and to explore potential preventive measures.