Refractive Outcomes in Monovision: Comparison of IOL Calculations With Distance, Intermediate, and Near Targets
To compare the accuracy of intraocular lens calculations of the distance eye to the near eye in patients receiving monovision correction from cataract surgery.
We performed a retrospective review of consecutive cases of phacoemulsification and monofocal intraocular lens placement with monovision (one eye set for distance, one eye set for intermediate/near) at Baylor College of Medicine. Uncomplicated cases performed between January 2011 and September 2014 were included in the study. Patients with postoperative best-spectacle corrected visual acuity of worse than 20/30 were excluded. Patients were evaluated at 3 weeks or longer postoperatively. The refractive prediction error was calculated as the difference between the actual refractive outcome postoperatively and the predicted refraction. Refractive prediction errors in eyes for distance and eyes for near/intermediate targets were compared.
Sixty-two eyes of 31 patients were included. Mean target refractive error in the near eye was -1.61 diopters (D) (range -2.67 to -0.95 D) while mean target refractive error in the distance eye was -0.30 D (range -0.96 to 0.27 D). Among 31 eyes targeting near vision, post-operative outcomes were 0.05 D more hyperopic than predicted while among the 31 eyes targeting distance visual acuity, post-operative spherical equivalent outcomes were 0.13 D more hyperopic than predicted by the Holladay 1 formula. There was no statistically significant difference between the refractive errors of near and distance eyes (p=0.46).
Monovision allows patients to achieve spectacle independence after cataract surgery with excellent vision both at near and at distance. Without the additional expense associated with accommodating and multifocal intraocular lenses, monovision remains an excellent option with reliable outcomes predicted by intraocular lens calculations based on the Holladay 1 formula.