Author: Catarina Castro (Portugal)
Co-authors: Catarina Castro, João Heitor Marques, Ana Marta, Pedro Baptista, António Ribeiro, Irene Barbosa
Purpose
To analyze macular retinal layers’ structure in diabetic eyes and to compare eyes with and without diabetic retinopathy (DR). Secondarily, we intend to assess the impact of laser treatment on macular structure.
Setting/Venue
Department of Ophthalmology, Centro Hospitalar Universitário do Porto, Porto, Portugal
Methods
Cross-sectional observational study that included diabetic patients with stable ocular disease and age-matched controls. Exclusion criteria were the presence of macular edema or epiretinal membrane and previous intravitreal treatment. Spectral-domain optical coherence tomography (SD-OCT) imaging was performed with Heidelberg Spectralis (Heidelberg Engineering®). The following layers were automatically segmented and its thickness was measured in the central 6 mm circle: Nerve Fibers Layer (RNFL), Ganglion Cell Layer (GCL), Inner Plexiform Layer (IPL), Inner Nuclear Layer (INL), Outer Plexiform Layer (OPL), Outer Nuclear Layer (ONL) and Retinal Pigment Epithelium (RPE). Thickness of Outer Retinal Layers (ORL, from external limiting membrane to Bruch’s membrane) and overall Retinal Thickness (RT) were also recorded. Best corrected visual acuity (BCVA) was recorded in the logMAR scale.
Results
A total of 289 eyes of 204 patients, with a mean age 69.1±11.2, 60.3% female, were included. That comprised 134 (46.4%) non-diabetic eyes, 63 (21.8%) diabetic eyes without DR, 45 (15.5%) eyes with untreated DR and 47 (16.3%) eyes with treated DR. There were no age differences between the groups compared (p>0.074). There was a significant decrease in RPE (p=0.040) and ORL thickness (p=0.025) in diabetic eyes without DR, when compared to non-diabetic eyes. There was an increase in INL thickness (p=0.015) of diabetic eyes with untreated DR compared to diabetic eyes without DR. There was an increase in OPL thickness (p=0.007) of diabetic eyes with treated DR when compared to diabetic eyes with untreated DR. In diabetic eyes, BCVA correlates with GCL (r=-0.278, p<0.001), IPL (r=-0.250, p=0.002), RPE (r=-0.162, p=0.043) and ORL (r=-0.198, p=0.013).
Conlusions
The earliest changes in retinal structure of diabetic eyes without DR may be localized in the ORL. Further changes may be localized in the INL, when DR is clinically first noticed and in the OPL when DR is submitted to laser treatment.
Financial Disclosure
The authors have no financial disclosures
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