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Gary L. Yau, Paolo Sandico Silva, Leo DP Cubillan, Karlo Marco D. Claudio, Kevin Mathew B. Panggat, Migil G. Ledesma, Maria Angelica DF Villano, Joanne Christine E. Macenas, Cloyd M. Pitoc, Carisa Mariella A. Paraz, Jennifer K Sun, Lloyd P Aiello; Impact of Ultrawide Field Retinal Imaging (UWFI) on the Rapid Assessment of Avoidable Blindness and Diabetic Retinopathy(RAAB-DR) Survey. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5450.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the feasibility and benefit of implementing UWFI within the efficient and cost-effective survey method of RAAB-DR used to estimate prevalence and causes of visual impairment(VI) in Central Luzon, Philippines
The RAAB-DR methodology estimates the prevalence of blindness, diabetes mellitus (DM) and DR in a defined geographic area. Community clusters(N=35) each with 50 subjects >=50 yrs old were selected by probability proportionate to size sampling for entry into this cross-sectional population-based survey. Participants received visual acuity(VA) screening and VI diagnosis by a study certified ophthalmologist. Subjects were classified as having DM if they had a previous diagnosis, were receiving DM treatment or had HbA1c >=6.5%. DM subjects were further assessed for DR by dilated biomicroscopy(direct and indirect). All subjects had nonmydriatic UWFI(2 stereo 200o images/eye; Daytona, Optos plc, Scotland, UK). Retinal images were evaluated by Joslin Vision Network protocol at a centralized reading center. Main outcome measures were prevalence and primary causes of VI(<20/40), prevalence of DR based on UWFI, and agreement between UWFI and dilated biomicroscopy for DR severity.
1750 individuals were identified and 1440(82.3%) evaluated. VA was >=20/40 in 1090(75.1%). The 3 top causes of VA <20/40 were untreated cataracts(n=219,62%), refractive error(n=81,23%) and posterior segment disease(n=27,8%). UWFI was done in 1358 subjects(94.3%), with ungradable images in 22(1.6%). Non-DR posterior segment disease was identified in 341(23.7%) and DM found in 377(26.1%) subjects. DR severity distribution(by UWFI) was: no DR=69.5%, mild non-proliferative DR(NPDR)=11.1%, moderate NPDR=9.3%, severe NPDR=2.7%, proliferative DR=5.0%, DME=5.6% and ungradable=2.4%. Linear-weighted DR severity agreement between UWFI and dilated biomicroscopic exam was substantial(k=0.64,95% CI,0.56-0.72), with exact agreement in 75.8% and within 1-step in 95.4%. UWFI identified more severe disease in 17.8%.
Relatively high rates of DM and DR are found in this diverse low-to-middle income population. As the first RAAB-DR survey to use UWFI, our study demonstrates that UWFI can be readily incorporated, has substantial agreement with biomicroscopy and appears to improve the ability to identify DR and non-DR retinal disease in such population-based surveys.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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