Optical coherence tomography as a diagnostic intervention before cataract surgery—a review

Author: Ahmed TM, Siddiqui MAR, Hussain B.

Geographical coverage: Asia, Europe, and the USA

Sector: Service Delivery

Sub-sector: Case detection / diagnosis

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background

Cataracts are a major cause of age-related vision loss. Phacoemulsification and intraocular lens (IOL) implantation are standard treatments. Advancements in surgical techniques have improved outcomes and raised patient expectations. Suboptimal results often stem from undetected macular pathologies, which may be missed during fundus examinations, especially with poor dilation or dense cataracts. This can lead to patient dissatisfaction and even litigation, particularly with premium IOLs, if pathology is not disclosed during the consent process. Spectral-domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) are advanced imaging technologies that allow non-invasive macular imaging through media opacities, improving preoperative assessments.

Objectives

To summarise the literature on the use of SD-OCT and SS-OCT in detecting macular pathology prior to cataract surgery, and to appraise their diagnostic efficacy.

Main findings

The review included 11 studies published between 2011 and 2019. Of these, 10 were case series and one was a cross-sectional study. Studies were conducted in Italy, Brazil, France, China, Pakistan, the United States, Germany (2 studies), and Austria (2 studies).

Nine studies assessed the added diagnostic value of OCT screening compared with standard fundoscopic examinations. These studies typically excluded patients with visible abnormalities. OCT identified previously undetected macular pathology in 13.7% of screened cases—approximately 1 in every 7.3 eyes. The two remaining studies included patients with abnormal fundoscopic findings and found OCT detected additional pathology in 10.2% and 17.5% of cases.

SD-OCT was found to be more sensitive than SS-OCT for certain macular pathologies, although SS-OCT was particularly effective for identifying macular holes and intraretinal fluid. However, SS-OCT’s smaller scan zone limited its sensitivity for detecting epiretinal membranes and geographic atrophy.

The most common pathologies identified by OCT included macular degeneration (42.9%), interface abnormalities (primarily epiretinal membranes; 32.2%), and macular oedema (18.4%). These pathologies are often missed during routine fundus examination and can negatively impact postoperative outcomes, reinforcing the clinical value of OCT in preoperative evaluation.

Methodology

Searches were conducted on 16 February 2021 in Medline, Embase, and the Cochrane Library. Reference lists of included studies were also screened. Only English-language studies were included. Data was extracted and analysed both qualitatively and quantitatively, but the review did not specify how many reviewers conducted the screening or data extraction. The review also did not assess the quality or risk of bias of the included studies.

Applicability/external validity

The review did not explicitly discuss external validity. However, the inclusion of studies from diverse countries and clinical settings suggests broad generalisability. The clinical relevance of detecting occult macular pathology using OCT prior to cataract surgery is well supported. A cost-effectiveness analysis within the review further supports routine OCT screening from both societal and payer perspectives.

Geographic focus

Studies were conducted in Asia, Europe, and the USA.

Summary of quality assessment

Overall, there is low confidence in the conclusions due to methodological limitations. The search was restricted to English-language publications. There was no reporting on the number of reviewers involved in screening or data extraction. The review did not evaluate the quality or risk of bias in included studies, nor did it explore heterogeneity in study results.