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Overnight thickness variation in diabetic macular edema
Michael Larsen1, Maria Wang, Birgit Sander
1Department of Ophthalmology, Herlev Hospital, University of Copenhagen, Denmark. mla@dadlnet.dk
Investigative Ophthalmology & Visual Science
|June 28, 2005
Summary
Overnight, diabetic macular edema worsens, increasing retinal thickness and decreasing visual acuity. This nocturnal thickening is linked to blood pressure changes and other factors, indicating impaired fluid regulation.
Area of Science:
- Ophthalmology
- Diabetology
- Retinal Diseases
Background:
- Diabetic macular edema (DME) is a leading cause of vision loss in diabetic patients.
- Nocturnal variations in retinal thickness and their impact on visual acuity in DME are not fully understood.
Purpose of the Study:
- To investigate the diurnal variation in retinal thickness in patients with fovea-involving DME.
- To correlate overnight changes in retinal thickness with visual acuity and physiological parameters.
Main Methods:
- Optical coherence tomography (OCT) was used to measure macular thickness in 12 patients with DME and 14 healthy controls.
- Measurements were taken in the evening and morning after overnight sleep in a recumbent position.
Main Results:
- Patients with DME showed a significant overnight increase in macular thickness (316 to 336 micrometers) and a decrease in visual acuity.
- The overnight increase in retinal thickness correlated with changes in mean arterial blood pressure (MABP) but was also influenced by other factors.
- Healthy subjects exhibited no significant overnight changes in retinal thickness or visual acuity.
Conclusions:
- Overnight retinal thickening in DME is associated with reduced visual acuity and is partly related to nocturnal blood pressure fluctuations.
- The findings suggest impaired regulation of retinal capillary filling pressure and other mechanisms, such as postural venous pressure changes and dark-induced retinal metabolism, contribute to DME progression.