The outer region of larger OCT angiography (OCT-A) macula scans may provide valuable diagnostic information for mild glaucoma that may not be detectable on smaller scans, a study in the Journal of Glaucoma suggests. Additionally, the research team found 6x6mm scans were on par with smaller 3x3mm scans in differentiating between healthy eyes and those with moderate to severe glaucoma.

Patients were enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) and had good quality images of the macula taken on the same day. The study included 89 healthy eyes, 127 eyes with mild glaucoma and 63 eyes with moderate to severe glaucoma. The researchers calculated the diagnostic accuracy of both scan sizes in the three groups. Ganglion cell complex (GCC) thickness was also included in the analysis.

The study found the diagnostic accuracy of vessel density using the 6×6mm macula OCT-A scan was better than the 3×3mm image when differentiating between healthy and mild glaucoma and similar to the 3×3mm scan when differentiating between healthy eyes and moderate to severe glaucoma.

Additionally, the vessel density of the inner area of the larger scans had similar diagnostic accuracy to the corresponding area of the 3×3mm scan in both diagnostic categories.

Researchers suggested it’s possible there is less of a difference between outer and inner sector accuracy in moderate and severe cases due to the likelihood of the central macula being damaged.

Penteado RC, Bowd C, Proudfoot J, et al. Diagnostic ability of optical coherence tomography angiography macula vessel density for the diagnosis of glaucoma using difference scan sizes. J Glaucoma. January 21, 2020. [Epub ahead of print].