Clinical context

Cataract surgery outcomes are not defined by best-corrected visual acuity alone. Refractive accuracy, vision at different distances, spectacle dependence, contrast sensitivity, dysphotopsia and procedural safety all matter. Corneal and macular status, capsular support, cataract density and IOL calculation also shape the final result. A statistically convincing average therefore still has to be interpreted against the characteristics of an individual eye.

What was studied

After simultaneous-vision IOL implantation, chart acuity may not fully describe everyday function. This retrospective analysis used 12-month data from 276 people with Full-DOFi Smooth or Partial-DOFi Extended IOLs. Binocular uncorrected acuity was measured at 4 m, 66 cm and 40 cm. Without spectacles, participants completed a validated Spanish VF-14 questionnaire. Each task was dichotomized into little/no difficulty versus other responses; logistic regression assessed associations, and the Youden index explored possible thresholds.

How the evidence was produced

A cohort study describes how outcomes are associated with an exposure or treatment in an observed clinical population. This design is useful for routine practice, uncommon events and longer follow-up, but it remains vulnerable to confounding by indication, baseline risk differences and missing data. An association should not automatically be interpreted as a causal effect.

Key result UDVA was significantly associated with reading traffic signs and night driving, P<.05; watching television had P=.06. UNVA was associated with knitting, P<.05, while large print had P=.06. UIVA was associated with reading newspapers, P=.02. Small print and knitting were associated with both UIVA and UNVA, while filling out forms was associated only with UNVA, P<.05. No significant acuity association was found for the remaining VF-14 activities. Exploratory Youden thresholds were generally 0.1 logMAR, except 0.3 logMAR for large print and 0.2 logMAR for traffic signs.

How to interpret the result

Different testing distances corresponded to different tasks, but no single acuity measure explained overall visual function. A nonsignificant association does not make a task unimportant: contrast, illumination, dysphotopsia, cognition, motor ability and adaptation also matter. The thresholds are most useful for developing patient-reported outcome tools, not as clinical success boundaries for a particular IOL. Counseling should address the patient's priority distances and activities, while follow-up should combine chart measures with functional and quality-of-vision questions.

Clinical applicability

This evidence is most useful as a basis for preoperative discussion and surgical planning. It helps identify which outcomes should be measured and which trade-offs should be explained to patients. The average effect should not be generalized to every IOL, technique or patient without checking eligibility criteria, surgeon experience, biometry, ocular comorbidity and duration of follow-up.

Limitations

This retrospective observational analysis cannot establish causality and included only two IOL designs. Dichotomizing responses discards severity information. Multiple questionnaire items and regressions increase chance findings unless multiplicity was addressed. Youden thresholds were derived in one dataset and need external validation. Effect sizes and confidence intervals were absent from the abstract. Verify the parent study, IOL allocation, refraction, eligibility, missing data, fellow-eye handling, VF-14 language validation, multiplicity correction, contrast and dysphotopsia, funding and conflicts.

What to verify in the source

Use the DOI below to verify complete methods, result tables, funding and conflicts of interest.