Intraoperative Anterior Segment Optical Coherence Tomography in the Management of Cataract Surgery: State of the Art

Authors: Toro MD, Milan S, Tognetto D, Rejdak R, Costagliola C, Zweifel SA, Posarelli C, Figus M, Rejdak M, Avitabile T, Carnevali A, Giglio R.

Geographical coverage: Not reported

Sector: Cataract surgery

Sub-sector: Management

Equity focus: Not reported

Study population: Patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Cataract surgery has significantly evolved over the past few decades and has become a safer and more effective procedure thanks to minimally invasive techniques and advanced technology. It is one of the most cost-effective medical interventions, improving the physical and psychological well-being of patients. Recently, intraoperative optical coherence tomography (i-OCT) has been integrated into surgical microscopes, enabling real-time, high-resolution imaging of ocular structures even through media with significant opacity. Despite its promising capabilities, the full scope of i-OCT’s clinical benefits remains unclear.

Objective: To summarise the current applications of anterior segment (AS) i-OCT in the management of cataract surgery, while also assessing the level and quality of evidence in the studies included in the review.

Main findings:

The review included 13 studies. Ten were prospective and three were retrospective. Most studies were graded as low or very low quality (GRADE level 4 evidence), and their evidence levels were mainly level 4 according to the Oxford Centre for Evidence-Based Medicine guidelines, with only one study reaching level 3. The studies varied in design, sample size, and focus, but collectively they highlighted the potential benefits and limitations of i-OCT in various aspects of cataract surgery.

A key application of i-OCT was assessing wound morphology and detecting complications, such as Descemet membrane detachment (DMD). For instance, Titiyal et al. found that ragged slit corneal incisions were more likely to lead to DMD. i-OCT was particularly useful in detecting the onset or progression of DMD during stromal hydration, which is not always visible through the operating microscope. The review also explored the use of i-OCT in femtosecond laser-assisted cataract surgery (FLACS). Palanker et al. and Mastropasqua et al. reported that laser capsulotomies guided by i-OCT were more precise and perfectly circular compared to manual capsulorhexis, leading to better intraocular lens (IOL) centration.

In terms of IOL positioning, Hirnschall et al. found that intraoperative measurements of the anterior capsule position – especially after inserting a capsular tension ring – were strong predictors of the postoperative IOL position. However, this approach required additional surgical steps not typically used in routine cases. The review also highlighted i-OCT’s utility in complex cases. For example, Titiyal et al. were able to classify white cataracts and posterior polar cataracts based on i-OCT findings, enabling surgeons to anticipate complications like an extension of the capsulorhexis or posterior capsule rupture.

Methodology:

The literature search was conducted in PubMed to identify articles on the use of AS i-OCT in patients undergoing cataract surgery. Studies published in English from the inception of the database up to November 2021 were included. Additionally, reference lists of all identified articles were scanned for further relevant publications.

Two reviewers independently screened the articles against the eligibility criteria. Any disagreements were resolved through discussion or by consulting a third reviewer. The findings from the included studies were synthesised narratively. The level of evidence for each study was assessed according to the Oxford Centre for Evidence-Based Medicine (2011) guidelines, and the quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

Applicability/external validity:

The review did not explicitly discuss the generalisability of its findings to clinical practice. However, it noted several limitations to the use of i-OCT in cataract surgery: intraoperative measurements can be time-consuming; many surgical instruments are not designed to be OCT-friendly; imaging quality may be reduced in very dense cataracts; and there was considerable heterogeneity among the included studies, most of which were low in quality. The authors underscored the need for further high-quality research (ideally, higher-level evidence studies) to validate i-OCT’s role and determine its true benefits in cataract surgery.

Geographic focus:

No geographical limits were applied to the search, and the review did not report the specific geographical distribution of the included studies. Therefore, it is not clear if the evidence is drawn from a broad international base or primarily from certain regions.

Summary of quality assessment:

Overall, there is low confidence in the conclusions about the effects of this study. The inclusion and exclusion criteria were clearly defined. Study quality was assessed using valid and reliable tools, and the findings of the assessment were provided. Two reviewers independently screened the articles, and the characteristics of the included studies were presented. The findings were synthesised narratively. The reference lists of identified studies were also scanned. However, a list of excluded studies was not provided. The findings were not reported according to risk of bias status. English language limits were applied, and it was not stated whether data extraction was conducted independently by multiple reviewers.