The Influence of stereopsis on ability to perform simulated cataract surgery

Abstract

Background The purpose of this study was to determine whether impaired or absent stereopsis affects ability to perform simulated microsurgical tasks. Methods A prospective randomized cross‐over study including 12 medical students. Visual acuity and stereoacuity were measured for all subjects. A band pass filter was placed over the non‐dominant eye to reduce stereoacuity to 150 seconds of an arc (partial stereopsis) or the non‐dominant eye was completely occluded (absent stereopsis). Participants completed a computerized surgical simulator task three times with the order of testing randomized (normal stereopsis, absent stereopsis and partial stereopsis). The task involved forceps to grasp and position objects in the anterior chamber. Outcomes included area of ocular injury, time to task completion and overall score. Results Ocular damage area was significantly worse when stereopsis was impaired to 150 seconds of an arc (p = 0.002), and worse still when stereopsis was absent (p < 0.001 for normal versus absent stereopsis and p = 0.005 for impaired versus absent stereopsis). The median ocular damage area was 3.55 mm2 (IQ range 1.21 to 5.88 mm2) with normal stereopsis, increasing to 6.10 mm2 (IQ range 3.96 to 12.47 mm2) with stereopsis reduced to 150 seconds of an arc and to 9.25 mm2 (IQ range 4.93 to 18.70 mm2) with no stereopsis. Time taken to complete the task increased and overall score decreased as stereopsis was reduced. Overall score decreased from 53% (IQ range 22.5 to 82%) under normal stereopsis to 0% (0 to 43.5%) with absent stereopsis. Conclusion Impaired stereopsis was associated with worse microsurgical performance which may have implications for surgical training. Absence of stereopsis resulted in worse performance than partial reduction in stereopsis.