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Robert Rosen, Linda Tsai, Aixa Alarcon, Kendra Hileman, Patricia Piers; A Bayesian method using through focus visual acuity to predict rates of spectacle wear for pseudophakic patients. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1075.
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© ARVO (1962-2015); The Authors (2016-present)
Spectacle independence, defined as a high rate of patients never wearing spectacles, is a desired outcome following cataract surgery. While methods exist for predicting clinical through focus visual acuity (VA) from pre-clinical data, there is a need for models that can estimate rates of spectacle independence for pseudophakic patients receiving different intraocular lenses (IOLs).
We used a data set of 321 patients from three different studies. The patients had been bilaterally implanted with either one of three different multifocal IOLs, an extended depth of focus (EDOF) IOL or a monofocal IOL. Spectacle wear was coded as a binary outcome, with patients answering that they wore spectacles a little, some, most or all of the time versus those that never wore spectacles. Through focus VA was coded in steps of 0.01 logMAR and measured in steps of 0.5D between -3D and 0D. We developed a Bayesian model to estimate rate of spectacle wear, and compared it with similar models using only VA at a single defocus. We evaluated the model by calculating the r2 coefficient of determination between the rates estimated by the model and the clinical results, and compared it with using a single defocus position. We also estimated the benefit of inducing 0.5D of myopia for the EDOF model.
The percentage of patients wearing spectacles predicted by the model correlated with the clinically reported rates, with R2=0.96. This was higher than any estimate using single defocus position (R2=0.84, 0.83, 0.45, 0.07, 0.03, 0.43, and 0.37 for defocus -3D to 0D in steps of 0.5D). The average absolute prediction error for the model was 5%, which compares favorably to the average prediction errors for single defocus positions (12%, 12%, 19%, 26%, 29%, 29% and 29% for the same defocus range). As can be seen in Fig. 1, the model predicted that an extended range of vision IOL with 42% wearing spectacles could have that rate decreased to 11% if the patients were made 0.5D myopic.
Rates of spectacle wear can be predicted from through focus VA. It is better to use a combination of VA at many distances than any one distance. Models based on combining clinical data from many studies might offer greater understanding of potential patient outcomes, such as predicting benefits from mini-monovision using EDOF IOLs.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Through focus VA for a theoretical EDOF model, and the same curve shifted 0.5D.
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