Preoperative Versus Postoperative Ocular Wavefront Changes After Scleral Implant Surgery for Treatment of Presbyopia
Narrative Responses:
Purpose
To determine whether the composition of ocular wavefronts, recorded using objective static and dynamic measurement methodologies, will reveal differences between pre- and post-operative eyes after scleral implant treatment for presbyopia, reflecting the postoperative subjective near visual acuity improvements which have been observed.
Methods
Emmetropes 50-60y/o were studied preoperatively and at 3M post-op intervals. Static wavefront measures were acquired while Sloane letters were viewed at 40cm, 66cm and 6m distances; for dynamic measures the target was alternated 33cm-6m-33cm during a 10s recording. Responses were filtered, scaled to minimum pupil size and analyzed to 6th Zernike order. Refractive power components, depth-of-focus, MTF, VSOTF-based acuity and other parameters were computed for individual frames and as time-series (dynamic). Correlations were performed for all considered estimators. Secondary depth-of-focus determinations were made for static acquisitions by measuring max/min amplitudes of refractive map data.
Results
Reliable and repeatable data recordings were obtained for all subjects. Of particular interest was the high correlation between estimators of the depth-of-focus, calculated at the 50% cut-off of the through-focus VSOTF and the predicted visual acuity. Statistically significant longitudinal changes from pre-operative baseline measures were observed in certain key wavefront and image quality metrics (spherical aberration, MTF, depth-of-field) which were associated with post-operative longitudinal improvements in uncorrected near visual acuity.
Conclusion
Compared to pre-operative baseline measures, significant objectively-measured postop changes in static and dynamic optical wavefront profiles are evident in study patients who received the scleral implant. These changes exhibit the trends of the subjective measures but do not fully explain the clinically-measured near visual acuity improvements.