Author: Carlotta Senni (Italy)
Co-authors: Enrico Borrelli, Domenico Grosso, Marco Trevisi, Rosangela Lattanzio, Giuseppe Querques, Francesco Bandello
Purpose
The detection of alterations in an early clinical phase could help in the prompt identification of patients at higher risk of diabetic retinopathy (DR) progression and in a better understanding of disease pathogenesis. The aim of this study was thus to evaluate the correlations between retinal blood flow alterations and scotopic and mesopic macular sensitivity in patients with treatment-naïve mild DR.
Setting/Venue
A prospective cross-sectional study was performed at IRCCS San Raffaele Scientific Institute. The study was approved by the local Ethical Committee and was conducted in accordance with the declaration of Helsinki.
Methods
In this prospective cross-sectional study 5 patients (10 eyes) classified as mild DR underwent a comprehensive multimodal imaging evaluation including swept-source optical coherence tomography angiography (SS-OCTA; PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). OCTA imaging of the macula included a 3x3-mm field of view area centered on the fovea (300 A-scans x 300 B-scans). En face OCTA images of the superficial capillary plexus (SCP) and deep vascular complex (DVC) were obtained and imported in ImageJ for analysis. For each result image, the perfusion density and vessel length density (PD and VLD) were measured. Furthermore, all subjects underwent mesopic and scotopic examinations of the central retina using the modified Macular Integrity Assessment device (S-MAIA, CenterVue Spa, Padova, Italy). While the mesopic testing was conducted under light-adapted conditions, the scotopic examination was performed following dark adaptation for 30 minutes. Spearman’s correlation coefficient was used to assess correlations.
Results
Mean±SD best corrected visual acuity was 20/20 Snellen in all the examined eyes. Mean±SD mesopic and scotopic macular sensitivities were 23.7±2.2 dB and 21.2±1.4 dB, respectively. The PD was 23.9±4.2 % at the SCP level and 37.2±2.3 % at the DVC level. The VLD was 3.5±0.9 % and 5.7±0.7 % within the SCP and DVC slabs, respectively. Both PD and VLD at the DVC level were correlated with mesopic (P=0.030 and P=0.041) and scotopic (P=0.045 and P=0.040) macular sensitivities. Conversely, PD and VLD at the SCP were not correlated with macular sensitivity (P=0.256 and P=0.350 for mesopic and P=0.299 and P=0.828 for scotopic macular sensitivities, respectively).
Conlusions
In eyes with early signs of DR, scotopic and mesopic macular sensitivities are significantly correlated with macular perfusion at the deep vascular complex. Assuming that perfusion at the DVC is known to contribute to photoreceptors’ function, our results may suggest that an early impairment of perfusion at this level may result in both cone and rod injuries.
Financial Disclosure
None
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