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Elena Bitrian, Dennis Mock, Kouros Nouri-Madhavi, Abdelmonem Afifi, Anne Coleman, Joseph Caprioli; Prediction of Regional Visual Field Thresholds in Early Versus Advanced Glaucoma With An Exponentional Prediction Model. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5497.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the prediction outcomes of an exponential model in patients with early and advanced glaucoma.
610 eyes with treated primary open-angle glaucoma, ≥6 years of follow-up and ≥10 reliable visual fields were included. Data for the initial four years or first half of the follow-up, whichever was longer, were used to predict the final thresholds at 51 locations across the 24-2 Humphrey visual fields. An exponential model had previously demonstrated the best overall fit and was used to predict the thresholds at the end of follow-up. A data-smoothing method using nerve fiber layer (NFL) clusters improved the prediction of thresholds in previous work and was used to weight the predicted thresholds at each location. The adjacent locations were weighted inversely proportional to the square of the distance to the reference location following a nerve fiber bundle pattern. Eyes were divided into two groups according to the initial mean deviation (MD): advanced glaucoma (MD -10 to -25.7 dB) and early glaucoma (MD -1 to -5.5 dB). Threshold sensitivities of the 51 locations at the end of the follow-up were predicted. The correlations of the predicted values with the actual values were determined for both groups and the differences between observed and predicted values were calculated.
301 eyes were included in the advanced glaucoma group (mean baseline MD -14.72 ± 3.41 dB) and 309 eyes were included in the early glaucoma group (mean baseline MD -3.19 ± 1.31 dB). The correlation R² between predicted and final measured values for individual threshold sensitivities were 0.48 (p < 0.001) for advanced and 0.55 for early glaucoma (p < 0.001). The average of the predicted minus observed thresholds was 11.29 ± 8.39 dB for the advanced glaucoma and 16.23 ± 8.75 for the early glaucoma group.
The exponential prediction model showed good correlation between observed and predicted values in both the advanced and early glaucoma eyes. An exponential model with NFL cluster data smoothing performs well to predict visual field outcomes in both early and more advanced stages of glaucoma.
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