Abstract
Purpose :
Handheld binocular infrared autorefractors are often used to screen children for amblyopia risk factors and are particularly useful in international medical mission work. To assess whether noncycloplegic devices could be used to prescribe glasses for children, a retrospective clinical study compared the noncycloplegic SPOT autorefractor readings to cycloplegic refractions performed during recent medical missions in the Andean region of Ecuador. Preliminary models were created to better predict a pediatric ophthalmologist’s eventual prescription from SPOT’s refractive values alone.
Methods :
Values for sphere (sph), cylinder (cyl), and axis for both right (OD) and left (OS) eyes were measured from 305 patients, ages 3-24, who presented at Partners for Andean Community Health located in Ecuador. Each patient’s refractive error was analyzed using SPOT and were compared to a standard dilated refraction (WRX) and the final prescription (Rx). Each variable’s measurements were compared across different linear regression models: a linear model, a quadratic model, and a polynomial model to the power of 4 degrees. The R2 dictated the model of best fit. All analyses were conducted using RStudio 2022.07.2 in January 2023.
Results :
All measurements had at least one model fit a range of data with good predictability. 3 models with the highest predictability were the Spot OD cyl vs final Rx (R2=0.60), the Spot OD cyl vs WRX (R2=0.76), and the Spot cyl OS vs the final Rx at an (R2=0.72). Preliminary refraction prediction model equations were also found to go from Spot to the final Rx for OD sph (y= -0.827+21.2x-4.38x2-3.09x3-0.0664x4), OS sph (y=-0.755+14.8x-13.3x2-6.02x3+5.45x4), OD cyl (y=1.79+22.3x-1.9x2-1.35x3-0.855x4), OS cyl (y=1.95+14.6x+9.96x2-7.67x3+0.0728x4), OD axis (y=95.7 +91.2x-40.4x2-162x3+50.3x4), and OS axis (y=87.5+80.8x+56.1x2-39.4x3+13x4).
Conclusions :
Preliminary tests prove that the gap between the SPOT autorefractor, the standard dilated refraction, and the final prescription can be modeled and better predicted. Further analyzation of the bounds of the predictive ranges and improved outlier removal will increase the usability of the model. Continual improvement of these tools may allow the use of binocular infrared autorefractors in under resourced areas to provide a good starting point for pediatric glasses prescriptions and may allow training of non-ophthalmic providers to prescribe glasses.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.