Understanding and Optimising Ocular Biometry for Cataract Surgery in Dry Eye Disease: A Review

Authors: Nibandhe AS, Donthineni PR.

Geographical coverage: Not reported

Sector: Cataract surgery

Sub-sector: Dry eye

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Globally, dry eye disease (DED) has become increasingly prevalent, affecting up to 50% of the population worldwide. It disrupts tear film homeostasis through tear instability, hyperosmolarity, inflammation, and neurosensory dysfunction, which significantly impact vision and quality of life. The tear film is essential for accurate ocular surface measurements (such as corneal topography and ocular biometry), and these measurements are crucial for cataract surgery planning. In DED, altered tear dynamics impair these measurements, leading to suboptimal surgical outcomes. Technological advances have raised both surgical precision and patient expectations, but DED can hinder the success of even routine cataract procedures. The presence of undiagnosed DED contributes to refractive errors, visual disturbances, and postoperative dissatisfaction. Therefore, understanding and addressing DED’s impact on preoperative biometry is essential for optimising surgical outcomes.

Objective:

To understand the impact of DED on the components of ocular biometry and to identify ways to optimise the visual outcomes of cataract surgery in eyes with DED.

Main Findings:

The review synthesised findings from a variety of study types, including meta-analyses, systematic reviews, case-control studies, cohort studies, case series, and laboratory investigations. It revealed that DED significantly alters tear film stability, leading to optical aberrations, variable keratometry readings, and inaccuracies in intraocular lens (IOL) power calculations. These disruptions reduce the reliability and repeatability of biometry measurements, increasing the risk of refractive surprises after cataract surgery.

The review highlighted how DED degrades visual quality through tear film hyperosmolarity, reduced mucin production, and ocular surface inflammation, all of which disrupt the precorneal refractive surface. It emphasised that keratometric measurements can be highly variable, particularly in older patients who commonly undergo cataract surgery. Studies showed that tear film instability leads to significant fluctuations in keratometry, necessitating repeated measurements to ensure accuracy. The review also addressed the influence of artificial tears and other topical treatments on keratometric measurements, noting that these agents can temporarily distort results. Importantly, it presented data supporting the preoperative optimisation of the ocular surface, particularly with treatments such as cyclosporine, lifitegrast, and rebamipide. These treatments improved ocular surface regularity, reduced higher-order aberrations (HOAs), and increased the predictive accuracy of IOL power calculations.

Methodology:

The literature search was conducted using multiple databases and clinical trial registries, including PubMed, MEDLINE, Cochrane CENTRAL, the metaRegister of Controlled Trials (mRCT), ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform. Relevant studies published in English from the year 2000 onwards were included. Studies were included if they reported any of the following: the burden of pre-existing and postoperative DED in the context of cataract surgery; the effects of dry eye on the ocular surface; variations in ocular biometry due to dry eye; or management options to ameliorate refractive surprises after cataract surgery in eyes with DED.

Applicability/External Validity:

The review did not explicitly discuss the applicability or external validity of its findings.

Geographical Focus:

No geographical limits were applied to the literature search; however, the review did not report the geographical distribution of the included studies. This omission makes it unclear whether the findings are globally representative or dominated by particular regions.

Summary of Quality Assessment:

Overall, there is low confidence in the review’s conclusions. On the positive side, the review performed searches across multiple databases and clearly defined inclusion and exclusion criteria, and it synthesised findings narratively. However, several limitations were noted. The review was limited to English-language studies, which introduces a language bias. It did not report whether multiple reviewers independently screened the articles or extracted data, raising the possibility of selection bias. The authors did not provide lists of included or excluded studies, nor did they report whether reference lists of included studies were checked for additional references. The characteristics of the included studies were not sufficiently presented, and importantly, the review did not report any assessment of the risk of bias of the included studies. These shortcomings limit the confidence that can be placed in the review’s conclusions.