Factors Affecting Near Vision And Pseudoaccomodation After Monofocal Intraocular Lens Implantation

The aim of this prospecitve study was to compare the factors affecting best uncorrected near vision acuity (UNVA) after ultrasound phacoemulsification cataract surgery (PHACO) and monofocal intraocular lens (IOL) implantation among patients divided into two groups according UNVA and pseudoaccommodation. The correlation and influence of axial length (AL), anterior chamber depth (ACD),cumulative dissipated energy (CDE), estimated fluid used (EFU) and corneal astigmatism on pseudoaccommodation and UNVA were analysed.This prospective cohort study was conducted at the Department of Ophthalmology,Universitiy Hospital Center Osijek,Croatia from January till February 2024  and enrolled 30 patients of both gender with cataract who underwent PHACO.  

Exclusion criteria were pre-existing irregular astigmatism,ocular surface disease,previous eye surgery,keratoconus,diabetes or any eye pathology that could lower postoperative best corrected visual acuity(BCVA).All patients underwent ophthalmic examination,IOL power calculation,AL,ACD,CDE,astigmatism and BCVA measurement on the day of the surgery and 30 days after PHACO and underwent PHACO surgery followed by monofocal IOL implantation(AAB00 Johnsson&Johnsson) done  by the same surgeon.

Patients were divided in two groups: with UNVA and pseudoaccommodation who could read≥Jager 4 and no pseudoaccommodation who read < Jager 4 without glasses.The mean age of patients was 75± 10.Most of patients were males(53%) versus female(47%),with no statistically significant difference between gender(Fisher exact test,p-value=0.71).63% patients had pseudoaccommodation and good UNVA.60 % patient had AL 22,5-25 mm,while 33 % had short AL<22,49mm.BCVA was improved after PHACO in both groups (Wilcoxonov test,p<0.001) with preoperative BCVA 0.4±0.1 and postoperative BCVA 1.0(-0.1) (Wilcoxon test,p<0.001).AL(Fisher exact test,p-value=0.18)and CDE(Mann WhitneyU test;Kruskal Wallis test(Post hoc Conover,p=0.06,p=0.07) did not have impact on UDVA.

ACD(Mann WhitneyU test,p=0.59,p=0.93),EFU(Mann Whitney U test,p=0.38),AST(Mann Whitney U test p=0.75),IOL power (Fisher exact test,p-value=0.08)did not have significant impact on pseudoaccommodation.70% of patients had preoperative with the rule astigmatism (WTR),20% had against the rule (ATR),but with no difference in distribution before and after PHACO regarding pseuodaccommodation(McNemar-Bowker test,p=0.31,p=0.56).Mean CDE in patients with pseudoaccomodation was 5.25(IQR 2.32-7.34) and in group with no pseudoaccommodation was 11.56(IQR4.12-20.19) but with no statistically significant difference among groups and influence on pseudoaccommodation. 

The difference in EFU among two groups was not statistically significant although EFU in the group with good pseudoaccomodation was slightly lower - 36 ccm versus  44 ccm in the group with no pseudoaccommodation.

PHACO resulted in significant improvement in BCVA. Although results confirmed a significant proportion of patients with good UNVA and pseudoaccommodation after monofocal IOL implanatation, our results did not confirm any correlation and impact of AL, CDE, EFU, astigmatism and IOL power on them. Pseudoaccommodation is yet phenomenon that has to be highlighted thinking about other possible causes like IOL shift, effective lens position, corneal multifocality and corneal higher order abberations.