Swept-source OCTA quantification of capillary closure predicts ETDRS severity staging of NPDR

• Published in: British journal of ophthalmology Vol. 106; no. 5; pp. 712 - 718
• Main Authors: Santos, Torcato, Warren, Lewis H, Santos, Ana Rita, Marques, Inês Pereira, Kubach, Sophie, Mendes, Luís G, Sisternes, Luis de, Madeira, Maria H, Durbin, Mary, Cunha-Vaz, Jose G
• Format: Journal Article
• Language: English
• Published: BMA House, Tavistock Square, London, WC1H 9JR BMJ Publishing Group Ltd 01.05.2022; BMJ Publishing Group LTD; BMJ Publishing Group
• Subjects: Classification; Clinical Science; Diabetes; Diabetes Mellitus, Type 2 - complications; Diabetic retinopathy; Diabetic Retinopathy - diagnosis; diagnostic tests/Investigation; Fluorescein Angiography - methods; Fundus Oculi; Humans; imaging; Medical diagnosis; Medical imaging; retina; Retinal Vessels - diagnostic imaging; Tomography, Optical Coherence - methods; retina; imaging; diagnostic tests/Investigation
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjophthalmol-2020-317890

PurposeTo test whether a single or composite set of parameters evaluated with optical coherence tomography angiography (OCTA), representing retinal capillary closure, can predict non-proliferative diabetic retinopathy (NPDR) staging according to the gold standard ETDRS grading scheme.Methods105 patients with diabetes, either without retinopathy or with different degrees of retinopathy (NPDR up to ETDRS grade 53), were prospectively evaluated using swept-source OCTA (SS-OCTA, PlexElite, Carl Zeiss Meditec) with 15×9 mm and 3×3 mm angiography protocols. Seven-field photographs of the fundus were obtained for ETDRS staging. Eyes from age-matched healthy subjects were also imaged as control.ResultsIn eyes of patients with type 2 diabetes without retinopathy or ETDRS levels 20 and 35, retinal capillary closure was in the macular area, with predominant alterations in the parafoveal retinal circulation (inner ring). Retinal capillary closure in ETDRS stages 43–53 becomes predominant in the retinal midperiphery with vessel density average values of 25.2±7.9 (p=0.001) in ETDRS 43 and 23.5±3.4 (p=0.001) in ETDRS 47–53, when evaluating extended areas of 15×9 protocol. Combination of acquisition protocols 3×3 mm and 15×9 mm, using SS-OCTA, allows discrimination between eyes with mild NPDR (ETDRS 10, 20, 35) and eyes with moderate-to-severe NPDR (ETDRS grades 43–53).ConclusionsRetinal capillary closure, quantified by SS-OCTA, can identify NPDR severity progression. It is located mainly in the perifoveal retinal capillary circulation in the initial stages of NPDR, whereas the retinal midperiphery is predominantly affected in moderate-to-severe NPDR.