Comparative Analysis Of Intermediate Vision: Spherical Monofocal Versus Aspherical Monofocal Versus Enhanced Monofocal Intraocular Lenses.

While the concept of inducing spherical aberrations to enhance intermediate vision is innovative, whether the inherent spherical aberrations in conventional spherical monofocal IOLs contribute to improving intermediate vision remains a pressing question. The objective is to compare intermediate vision and spherical aberrations among spherical monofocal, aspheric monofocal, and enhanced monofocal lenses. The study aims to investigate and quantify the potential contribution of spherical aberrations in spherical monofocal lenses towards enhancing intermediate vision and to delineate the extent of this effect. 

Nethradhama Super Speciality Eye hospital, Bangalore, India. 

This is a prospective, single center, interventional study in which 30 eyes are included in each arm of spherical monofocal, aspherical monofocal and enhanced monofocal intraocular lens groups. Post surgery on post operative day 15 and 3 months, uncorrected (UDVA) and distance corrected (CDVA) visual acuity, intermediate uncorrected (UIVA) and corrected (DCIVA) visual acuity and near uncorrected (UNVA) and corrected (CNVA) visual acuity were tested using ETDRS charts. Internal spherical aberrations with itrace aberrometry with 3mm pupil size were recorded and compared between three groups.  

30 eyes in each arm post operatively were tested on day 15 and 3 months. Mean age was 64+/-8.2, 67.1+/-9.2 and 65.8 +/- 9.9 years respectively in spherical, aspherical and enhanced monofocal IOLs. Mean UDVA in LogMAR was 0.09+/-0.08, 0.07+/-0.08 and 0.05+/-0.07 in spherical, aspherical and enhanced monofocal groups. Mean UIVA at 66cm in spherical group was 0.212+/-0.11 LogMAR and in aspherical group was 0.33+/-0.14 LogMAR with statistically significant difference (p=0.0006). UIVA at 66cm in enhanced monofocal group was 0.18+/-0.123 LogMAR which showed no statistically significant difference with spherical group UIVA (p=0.346). Internal spherical aberrations were 0.026, -0.024 and 0.022 in spherical, aspherical and enhanced monofocal groups.

Spherical monofocal IOLs, owing to their inherent spherical aberrations in the central region, exhibit superior intermediate vision which are nearly akin to enhanced monofocal IOLs, on contrast with aspherical monofocal IOLs,  The minimum level of internal spherical aberrations quantified to provide enhanced intermediate vision was identified to be approximately 0.02. Additional follow-up and extensive studies with larger datasets are warranted to fully elucidate these findings.