Efficacy and Safety of Cataract Extraction with Negative Power Intraocular Lens Implantation

Purpose: To evaluate the visual and refractive outcomes, lens power calculation accuracy, and safety of negative power intraocular lenses (IOLs) implanted in highly myopic eyes at the time of cataract surgery. Design: Interventional case series. Methods: Sixteen consecutive highly myopic eyes implanted with IOLs from -1 D to -6 D were identified. IOL power; preoperative and postoperative best-corrected visual acuity (BCVA); postoperative uncorrected visual acuity (UCVA); preoperative, intended, and achieved spherical equivalent (SE) refractive errors; and operative complications were recorded. Results: Median UCVA improved from finger counting to 20/50-2. Median BCVA improved from 20/125-1 to 20/30+1. Mean axial length was 32.65 mm. The mean SE refractive error was -22.19 +/- 5.4 D before surgery and -0.28 +/- 1.4 D after surgery. The difference between the mean intended and mean achieved SE refractive errors was + 1.16 D for the SRK/T, + 1.2 D for the Holladay 1, and +1.60 D for the Hoffer Q formulas. Only 5 (33.3%) of 15 eyes in which postoperative measurements were possible were within 1 D of the intended SE postoperative refraction. Postoperative complications included a mildly hyperopic postoperative refractive error (+1.75 D) in one eye necessitating an IOL exchange and posterior capsule opacification in most eyes. There were no retinal detachments. Conclusions: The SRK/T formula had the greatest accuracy and predictability when immersion A-scan ultrasonography was used to measure axial length. The mean achieved postoperative refractive error was + 1.16 D more hyperopic than predicted by this formula. We recommend targeting highly myopic eyes for -1.5 D using the SRK/T formula if a negative power IOL is calculated and emmetropia or mild residual myopia is the desired postoperative result.