Immediate Vs. Delayed Sequential Bilateral Cataract Surgery: Visual And Refractive Outcomes In Mono- Vs. Multifocal Intraocular Lens Implantation

Immediate sequential bilateral cataract surgery (ISBCS), involving surgery on both eyes within a single session, has gained popularity from extensive supportive research. We previously described that nearly 75% of ISBCS eyes achieve postoperative emmetropia. However, no study has yet compared visual and refractive outcomes between ISBCS and delayed sequential bilateral cataract surgery (DSBCS) with monofocal (mIOL) or multifocal (mfIOL) lenses. As ISBCS gains wider acceptance and the benefits of mfIOLs become more apparent, assessing their combined effects is essential. This study addresses this gap by exploring the visual and refractive outcomes of mfIOL implantation within ISBCS, to enhance our understanding and inform clinical practice.

Retrospective, multi-site, and multi-surgeon study analyzing cataract extraction procedures performed at Moorfields Eye Hospital NHS Foundation Trust from December 2023 to December 2024.

All eyes undergoing uncomplicated ISBCS or DSBCS with mIOL or mfIOL that met inclusion criteria were analyzed. Exclusions were made for combined procedures and those cases with ocular conditions affecting refraction and visual acuity measurements, including corneal ectasia, macular degeneration, diabetic retinopathy, and glaucoma. Visual and refractive outcomes were assessed at the first postoperative visit (POV1) from days 1 to 90. Primary outcomes included mean uncorrected visual acuity (UCVA), mean spherical equivalent (SE) refraction, and Mean Absolute Error (MAE). Data were analyzed with Kruskal-Wallis and Wilcoxon tests. Risk factor analyses for postoperative UCVA and SE was performed using Generalized Estimating Equation (GEE). 

A total of 11,620 eyes from 5,810 patients were analyzed. At POV1, mean SE (D) was –0.22 ± 0.82D (mIOL-DSBCS), -0.16 ± 1.11D (mIOL-ISBCS), –0.30 ± 0.46D (mfIOL-DSBCS), and -0.11 ± 0.43D  (mfIOL-ISBCS) (p < 0.001). Mean logMAR UCVA was 0.09 ± 0.19, 0.09 ± 0.19, 0.00 ± 0.10, and −0.05 ± 0.12, respectively (p < 0.001). Refractive accuracy analysis showed a significantly lower mean absolute error in the mfIOL groups than in the mIOL counterparts (mIOL-DSBCS: 0.46 ± 1.09; mIOL-ISBCS: 0.52 ± 1.46D; mfIOL-DSBCS: 0.29 ± 0.19D; mfIOL-ISBCS: 0.28 ± 0.27D; p < 0.001). GEE analyses confirmed younger age at presentation, preoperative VA and SE, and mfIOL-ISBCS as key predictors of better postoperative UCVA and SE (all p < 0.001).

In this large, multi-site, and multi-surgeon cohort, mfIOL implantation in ISBCS demonstrated better SE and UCVA compared to mfIOL-DSBCS, mIOL-DSBCS, and mIOL-ISBCS. Although the observed improvements were modest and potentially not clinically significant, these findings support the use of mfIOL in ISBCS. Further investigations are necessary to overcome current research limitations, particularly the lack of differentiation between types of multifocal IOLs (EDOF vs. Trifocal), and the disparity in subgroup sample sizes, as these factors could significantly influence the generalizability and interpretation of the results.