Detection of Fovea-Threatening Diabetic Macular Edema by Optical Coherence Tomography to Maintain Good Vision by Prophylactic Treatment

BACKGROUND/AIMS: To establish a screening and treatment method for fovea-threatening diabetic macular edema (DME) using spectral-domain optical coherence tomography (SD-OCT). In order to maintain good visual acuity (VA), focal/grid laser treatment for screened fovea-threatening DME was evaluated based on macular thickness map images produced by SD-OCT. METHODS: In 66 diabetic eyes with no visual deterioration, the sensitivity and the specificity of SD-OCT without the use of mydriatics for the detection of fovea-threatening DME were determined. A definite diagnosis of DME was made under mydriasis, using slitlamp biomicroscopy with a contact lens. Eyes with fovea-threatening DME then underwent prophylactic focal/grid laser treatment. The main outcome measures were corrected VA and central macular thickness (CMT). RESULTS: A definitive diagnosis of DME was made in 5 of the 66 eyes, while macular thickening above the 99th percentile was detected in 11 (Cirrus®) or 13 (RS-3000®) eyes by SD-OCT. The focal/grid laser treatment of the 5 eyes with fovea-threatening DME successfully maintained good VA, which was 0.91 ± 0.76 (average: 20/22; 0.04 ± 0.12 logMAR) before treatment and 0.89 ± 0.70 (average: 20/22; 0.05 ± 0.15 logMAR; p = 0.88) 1 year afterwards. The average CMT was stable before and after focal/grid lasering at 302 ± 29 and 329 ± 55 µm, respectively (p = 0.99). CONCLUSIONS: The detection of fovea-threatening DME is feasible by SD-OCT without using mydriatics. Prophylactic treatment, such as with focal/grid lasers, was effective in maintaining good VA by avoiding an otherwise highly likely foveal involvement.