What Determines The Near Visual Acuity Achieved With The Elon Extended-Depth-Of-Focus Intraocular Lens?

The purpose of extended-depth-of-focus (EDoF) intraocular lenses is to provide excellent distance and intermediate vision and good functional vision, but not necessarily perfect near visual acuity, so full spectacle independence is often not possible. However, after implantation of Medicontur ELON lenses, near vision is often better than expected. Our aim was to analyse which preoperative and postoperative parameters are associated with the near visual performance achieved with EDoF lenses.

University of Miskolc, Faculty of Health Sciences, Institute of Clinical Methodology, Miskolc and Elisabeth Spa Health and Conservation Center, Miskolc Klinikoptik Ophthalmic and Optical Center, Nyíregyháza, Prestige Medical Center, Nyíregyháza.

Before the surgeries, standard biometric data, higher order corneal aberrations (HOA) and kappa angle were measured with a Topcon Aladdin device. At least 4 weeks after surgery, we recorded subjective and objective refractive errors, visual acuity, including 40-45 cm near monocular visual acuity, the repeated biometric data and photopic and mesopic pupil diameter. Multivariate regression analysis was used to investigate whether there was any parameter measured pre- or postoperatively that was associated with postoperative near visual acuity.

Data from 143 eyes of 73 patients were analysed, with patient age ranging from 42.3 to 81.2 years and axial length from 20.88 to 26.35 mm. The mean of the near uncorrected visual acuity was 0.23 logMAR (SD: 0.12, range: 0.0-0.59). Multivariate regression models showed a significant correlation between axial length, anterior chamber depth, keratometric readings, postoperative pupil size and near visual acuity. No significant correlations were found with other parameters (e.g., planned postoperative refraction, HOA, kappa angle, corneal astigmatism, age).

The often better than expected near visual acuity achieved with the ELON intraocular lens may be due to specific anatomical factors in addition to better neuroadaptation, higher patient motivation and higher tolerance to defocus. Although these measurable factors are beyond our control, their observation may be useful in preoperative assessments, patient information and prediction of expected outcomes.