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Kate Brassington, Lyle Gurrin, Khin Zaw Aung, Robyn Guymer; Novel Laser treatment for Early Age-related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4146.
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© ARVO (1962-2015); The Authors (2016-present)
To study the progression of early age-related macular degeneration (AMD) after a nano-second pulse laser intervention compared to participants with natural history of AMD.
A proof of concept, case-control study using laser-treated participants as cases and participants with a natural history of AMD as controls. 48 participants with bilateral high risk early AMD received the intervention. A cohort of 70 participants with bilateral early AMD provided the natural history group for comparison. Ultra-low energy nanosecond 2RT laser pulses were applied in 12 spots around the macula of one eye (0.15mJ to 0.45mJ), using 400um diameter spot, 3 nanosecond pulse length, 532nm wavelength and titrated to each patient. All participants were seen at baseline, 12 months and 24 months best corrected visual acuity (BCVA) was recorded, fundus images macular visual function and DNA for genetic analysis were taken. Changes in BVCA, drusen area, macular function and progression to advanced AMD were assessed. Results of the univariate and multivariate logistic regression analysis for progression to advanced AMD are presented. The main outcome measured was the odds ratio of progression comparing laser intervention to historical controls. In the multivariate analysis we adjusted for known and others identified in the univariate analysis; age at baseline, smoking and the HTRA1 gene variants.
At 12 months, 3 of the 48 treated participants progressed to geographic atrophy whilst in the natural history control group 7 of the 70 progressed (p=0.48). At 24 months 4 participants in the treated group and 9 in the natural history progressed to geographic atrophy (p=0.60). Using multivariate analysis adjusted for age at baseline, smoking and the variants of HTRA1 gene, at 12 months and at 24 months follow up, the odds ratio (OR) for the risk of progression after laser intervention compared to those with natural history of AMD was found to be OR 0.43 (0.08, 2.24) and 0.56 (0.13, 2.38), respectively.
A single unilateral course of nanosecond laser to the macula suggests a potentially clinically significant reduction in the odds of progression to advanced AMD at 12 months and at 24 months. These results suggest the 2RT laser has the potential to slow progression of early AMD. A large randomised controlled trial is currently underway.
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