When is Refraction Stable Following Routine Cataract Surgery? A Systematic Review And Meta‐Analysis

Author: Charlesworth E, Alderson AJ, de Juan V, Elliott DB.

Geographical coverage: United States, United Kingdom, Germany, Spain, Japan, Denmark, Italy, Turkey

Sector: Cataract surgery

Sub-sector: Refraction

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

Cataract surgery is among the most frequently performed operations in the UK, and procedure numbers are expected to rise by 50 % between 2015 and 2035. Present guidance advises waiting 4–6 weeks post-operatively before prescribing new spectacles. However, modern surgical techniques—particularly smaller incisions—can allow the refractive error to stabilise much sooner. Evidence suggests that smaller incisions speed visual recovery and refractive stabilisation. Postponing spectacle provision can therefore impair patients’ quality of life, especially for those in employment or heavily reliant on good near vision. As the average age at surgery falls and expectations for rapid visual rehabilitation rise, it is timely to re-evaluate existing guidance to better reflect contemporary outcomes and enhance early post-operative visual function.

Objective: To determine when refraction becomes stable after routine cataract surgery with implantation of monofocal intra-ocular lenses.

Main findings:

Nine studies met the inclusion criteria, each assessing refractive stability (by automated or subjective refraction) following uncomplicated phacoemulsification.

Five studies sought to establish the timing of refractive stability; two compared standard phacoemulsification with femtosecond-laser-assisted surgery; the remaining two examined intra-ocular-lens selection.

Study locations were the United States (two), and one each in the UK, Germany, Spain, Japan, Denmark, Italy and Turkey.

Meta-analysis of five studies (301 eyes) comparing refraction at one week versus four weeks showed no statistically significant differences in spherical power (ES = 0.00; 95 % CI –0.17 to 0.17), cylindrical power (ES = +0.06; 95 % CI –0.05 to 0.17) or spherical equivalent (ES = –0.01; 95 % CI –0.12 to 0.10); heterogeneity was low (I² < 25 %).

Individual-patient data (n = 72) indicated that roughly 7 % of patients still had unstable cylinder at one week. Large early changes in cylinder power or axis were potential predictors of ongoing instability.

Overall, prescribing spectacles as early as one week after surgery appears safe for most patients, though clinicians should exercise judgement in atypical cases.

Methodology:

Searches of MEDLINE, CINAHL, AMED, Embase, Web of Science, the Cochrane Library and OpenGrey (to 1 August 2019) identified studies of adult patients undergoing uncomplicated cataract surgery. Citation chasing and author contact supplemented database searches. Inclusion was limited to studies from upper-middle- or high-income economies (World Bank definition) published in English. Two reviewers independently screened and extracted data; disagreements were resolved by discussion. Study quality was assessed with the Methodological Index for Non-Randomised Studies (MINORS). Meta-analysis, Cochrane Q and I² statistics assessed pooled effects and heterogeneity; publication bias was explored with funnel plots.

Applicability/external validity:

Most studies were single-centre, potentially limiting generalisability. Restricting inclusion to English-language publications from wealthier nations introduces geographical and language biases. Variation in surgical technique, refractive-testing methods and incomplete reporting of exclusions may further affect external validity. Group-level stability masked individual variability in a minority (~ 7 %) of patients; future work should identify predictors of delayed stability and validate findings across diverse settings.

Geographic focus:

Upper-middle- and high-income countries (United States, United Kingdom, Germany, Spain, Japan, Denmark, Italy, Turkey).

Summary of quality assessment:

The review employed comprehensive searches, explicit inclusion criteria and duplicate screening, yielding moderate confidence in its conclusions. Study characteristics were well described and the meta-analysis was appropriately conducted with low heterogeneity. Limitations include the language and income-level restrictions, absence of an excluded-studies list and lack of risk-of-bias-stratified results.