Abstract
Purpose :
The prevalence of high myopia (spherical refraction [SR] > -6D or an axial length > 26 mm) with a maximum recorded length of 37 mm is projected to increase from 2.7% to 9.8% by 2054. Retinal surgery requires instruments of sufficient length to reach the retina. To assist in the selection of appropriate instruments, modeling was conducted to estimate the length of instruments required for highly myopic eyes.
Methods :
A geometric model for a myopic eye was constructed as a guide to determine the length of an instrument required to reach the position of the retina furthest from the point of insertion. The anterior portion of the model included only the cornea, with anterior radius of 7.77 mm drawn to a white-to-white distance of 11.69 mm, and the anterior sclera of radius 13.12 mm extending from this point to a length of 3.5 mm, representing the point of instrument insertion at the pars plana. The posterior portion was comprised of the retinal surface from the posterior pole to +/- 11 mm from the optical axis, parameterized to allow the retinal shape and location to scale with mean SR, according to the model. Matlab code was written to determine the distance to the location on the retina furthest away from the point of insertion.
Results :
For the model eye, when axial length increased from 23.6 to 37.3 mm, maximum required instrument reach increased from 23.3 to 33.7 mm.
Conclusions :
An instrument with a maximum reach of 34 mm is sufficient to treat an eye with axial length up to 37 mm.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.