Study evaluates visual function, OCTA in eyes with PDR, macular capillary nonperfusion

Key takeaways:

• OCT angiography can measure changes in the foveal avascular zone (FAZ) area.
• FAZ area deteriorated in stable eyes with proliferative diabetic retinopathy and macular capillary nonperfusion.

The foveal avascular zone, or FAZ, area deteriorated at 12 months in eyes with stable laser-treated proliferative diabetic retinopathy and macular capillary nonperfusion, but vision loss was not common, according to a study.

“With the advent of optical coherence tomography angiography (OCTA), it is now possible to measure changes in FAZ area and other vascular metrics objectively over time,” Sridevi Thottarath, MS, of Moorfields Eye Hospital in London, and colleagues wrote. “Despite only modest correlation between changes in FAZ area and visual impairment over time, FAZ enlargement is used as a surrogate for macular CNP. The aim of this study was to evaluate changes in visual function and OCTA metrics over 12 months in laser-treated PDR eyes with macular CNP.”

The prospective, single-center, observational cohort study, published in JAMA Ophthalmology, enrolled 88 eyes of 63 patients with stable laser-treated proliferative diabetic retinopathy (PDR) and macular capillary nonperfusion (CNP) with a best corrected visual acuity letter score of at least 54 as measured by the ETDRS chart. Changes in BCVA, low-luminance visual acuity (LLVA) and OCTA metrics were recorded over 12 months.

At baseline, the mean BCVA letter score was 77.52, and the mean LLVA letter score was 68.33; at 12 months, the scores were 78.76 and 70.2, respectively. Overall, 9.3% of participants experienced a reduction of five letters or more of visual acuity, which was not associated with any baseline FAZ parameters.

FAZ area increased by a mean of 1.8% at 6 months (P = .049) and 2.26% at 12 months (P = .03), but vision loss was “uncommon and more prevalent in eyes with decreased SVD at baseline rather than FAZ parameters,” Thottarath and colleagues wrote.

A loss of five or more letters in BCVA at 12 months was linked with a lower mean baseline superficial vessel density (SVD) in both the macula 3mm ×3 mm area (P=.006) and parafoveal area (P=.005) OCTA scans.

“This study found that FAZ area continued to deteriorate over time although both BCVA and LLVA remained relatively stable over 12 months,” Thottarath and colleagues wrote. “Although the loss in BCVA of five or more letters was associated with baseline SVD parameters but not FAZ or [deep vessel density], deterioration of FAZ area was still associated with loss of BCVA at 12 months. However, the data failed to support the associations between FAZ area and LLVA.”

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Sources/Disclosures

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Disclosures:
Thottarath reports receiving grants from Boehringer Ingelheim during the conduct of the study and personal fees from Boehringer Ingelheim outside the submitted work. Please see the study for all other authors’ relevant financial disclosures.

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