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Xihui Lin, Kevin Bubel, Richard Winslow; Focal Laser Photocoagulation for Diabetic Macular Edema in an Inner City Population. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):5682.
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© ARVO (1962-2015); The Authors (2016-present)
The effectiveness of focal laser photocoagulation for diabetic macular edema (DME) is highly variable. Few studies to date have addressed parameters predictive of treatment success. We evaluated the effectiveness of focal laser for DME in a county hospital setting to identify patient and treatment factors that correlated with successful outcomes.
Resident-performed focal laser for DME at Parkland Memorial Hospital (Dallas, TX) from 1/13 to 9/14 were retrospectively reviewed. Patient demographics, hemoglobin A1c (HbA1c), prior treatments, fluorescein angiography, visual acuity, central subfield thickness (CST) and maximum subfield thickness (MST) on OCT were analyzed. The primary end points were visual acuity and retinal thickness 1 month after treatment. This study received IRB approval from University of Texas Southwestern Medical Center.
32 eyes treated by 7 physicians were reviewed. The average patient age was 58.4 years. 66.7% were male. The largest ethnicity was Hispanic (47.8%). Average HbA1c at the time of procedure was 8.2%. At 1 month, visual acuity improved from 20/65 pre-treatment (logMAR 0.514) to 20/50 (logMAR 0.392). Average CST and MST improved from 334.2 µm and 436.3 µm to 332.8 µm and 422.25 µm, respectively. HbA1c, prior laser treatments, intravitreal injections, or the availability of fluorescein angiography did not affect treatment success (P>0.3 for CST and MST). Patients with pre-treatment CST <400 µm had better results than those >400 µm (-7.8 µm vs. +102.3 µm, p<0.0001). Treatments targeting less than 5 micro-aneurysms had better success (MST change of -33.1 µm vs. +4 µm, p=0.02). The best results were obtained with 80-100 mW of power delivered over 0.1 s with MST change of -25.4 µm compared with +77.0 µm in those <80 mW and +41.4 µm in those >100 mW (p<0.05).
Focal lasers for DME performed on a mostly Hispanic cohort by resident physicians were able to improve visual acuity and decrease retinal thickness. Availability of fluorescein angiography, glycemic control, and prior treatments had no significant impact on outcomes. Selecting patients with CST <400 µm, less than 5 micro-aneurysms in the area of swelling, and using laser power between 80 - 100 mW were associated with greater success. These findings serve as a guideline to patient selection and treatment parameters in diabetic laser treatments but should be validated in different cohorts.
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