Dr Ray O’Connor continues his look at recent clinical papers on ophthalmology by turning his attention to cataract, which in 2020 represented the largest contributor to global blindness in adults aged over 50 years
Cataract, characterized by the clouding of the eye’s crystalline lens, is one of the leading causes of visual impairment and blindness worldwide, affecting millions of individuals, particularly the elderly.
In 2020, cataract represented the largest contributor to global blindness in adults aged over 50 years, with over 15 million individuals affected, which is approximately 45 per cent of the cases of global blindness. The global prevalence of cataract is rising due to population aging, posing a substantial public health burden and highlighting the need for effective prevention strategies. While aging remains the most significant risk factor, accumulating evidence suggests that metabolic disorders, such as metabolic syndrome (MetS), may also contribute to cataract development. However, the evidence remains inconclusive.
Dr Ray O’Connor
This meta-analysis1 aimed to clarify the potential association. The authors conducted a systematic search of PubMed, Embase, and Web of Science up to July 31, 2024, for observational studies evaluating the association between MetS and cataract. Data were pooled using a random-effects model to calculate risk ratios (RR). Ten studies with 379,464 participants were included in the final analysis.
The results showed that MetS was significantly associated with an increased risk of cataract (RR: 1.28). Subgroup analyses indicated that the association was stronger in participants aged ≥57 years compared to those <57 years. No significant differences were found by geographic region, sex, or cataract types. The authors concluded that is associated with an increased risk of cataract in adults, particularly in older populations. They recommend that further studies are conducted to explore the underlying mechanisms and develop prevention strategies.
Despite the growing recognition of the link between cataract and fracture, the available evidence remains inconclusive. The objective of this systematic review and meta-analysis2 was to evaluate the odds ratio (OR) and hazard ratio (HR) of bone fracture in phakic subjects (those having an intact, natural lens) with cataract compared with phakic subjects without cataract and pseudophakic (those whose lens has been replaced) individuals.
Four electronic databases were searched from their inception to May 2024: PubMed, Embase, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Sixteen articles met the predefined inclusion and exclusion criteria, with the 11 included in the quantitative synthesis encompassing a population of 4,713,458 subjects and reporting on 284 811 fractures.
The certainty of evidence was rated from low to moderate. Compared with subjects without cataract, the OR and the HR for fractures in the cataract group were 1.44 and 1.51, respectively. Bayesian analysis indicated that subjects with cataracts have an increased OR and HR of fractures compared with both phakic subjects without cataracts (OR: 3.0; HR 1.1 and pseudophakic individuals (OR: 1.7; HR: 1.28). Pseudophakic individuals exhibit a 27 per cent reduction in fracture risk compared with phakic individuals with cataracts.
The authors concluded that low-certainty evidence suggests a higher fracture risk in individuals with cataract compared with those without. Moderate-certainty evidence indicates that pseudophakic individuals have the lowest fracture risk compared with phakic patients with or without cataract. The authors recommend that further research should explore the causal link between cataract and fracture risk and evaluate the impact of cataract surgery on fracture prevention.
Traditionally, cataract surgery has been performed on one eye at a time, with a delay between surgeries, known as Delayed Sequential Bilateral Cataract Surgery (DSBCS). However, advancements in surgical techniques, anaesthesia, and infection control have led to the emergence of Immediately Sequential Bilateral Cataract Surgery (ISBCS), where both eyes are operated on during the same surgical session. ISBCS offers potential benefits, including reduced recovery time, fewer hospital visits, and lower healthcare costs, but it also raises concerns about the risk of bilateral complications, such as endophthalmitis, and logistical challenges in postoperative care.
The objective of this systematic review3 was to compare the visual outcomes, safety, and patient-reported outcomes of ISBCS versus DSBCS in adults undergoing cataract surgery. A systematic search of PubMed, Embase, CENTRAL, Web of Science, and gray literature (conference abstracts, registries) was conducted for studies published up to March 2023.
Eligible studies directly compared ISBCS and DSBCS in adults, reporting best corrected visual acuity (BCVA), complications, or patient-reported outcomes. Nine studies were included (three randomized controlled trials, five retrospective cohorts, one review), encompassing sample sizes ranging from 298 patients to over 496,000 eyes. Both ISBCS and DSBCS resulted in significant improvements in BCVA, withcomparable refractive accuracy. No significant differences were observed in serious complications such as endophthalmitis, cystoid macular oedema, or posterior capsular rupture. Some studies reported a trend toward slightly higher patient satisfaction and faster rehabilitation in the ISBCS group.
The authors concluded that ISBCS appears to be a safe and effective alternative to DSBCS in carefully selected patients, offering potential benefits in efficiency, recovery time, and patient satisfaction. They recommended that rigorous randomized controlled trials with standardized outcome measures and long-term follow-up are needed to further validate these findings.
The allocation of resources and appropriate strategies are essential for effective healthcare management that can control costs and improve patients’ quality of life in cataract surgery.
Clinical Practice Guidelines (CPGs) help reduce variability in care. The objective of this systematic review4 was to analyse, compare, and synthesize recommendations from multiple guidelines on the same topic in order to identify consistencies, discrepancies, and opportunities for improvement. Websites of international organizations, scientific societies, and various databases such as PubMed, Web of Science, and Cinahl were reviewed.
A systematic review identified five high-quality Clinical Practice Guidelines for cataract management, with recommendations covering diagnosis, treatment, and postoperative follow-up. Although some variability was found, common recommendations were identified.
Two widely agreed upon recommendations stood out: avoiding routine preoperative medical tests for local anaesthesia, as they do not reduce complications, and using intracameral antibiotics (cefuroxime/moxifloxacin) for infection prevention, supported by high-level evidence, among others.
The guideline developed by the American Academy of Ophthalmology – ‘Cataract in the Adult Eye Preferred Practice Pattern’ – was found to be the most valid and useful. The authors concluded that standardizing high-evidence recommendations can improve clinical decision-making, reduce variability, and enhance patient outcomes. This study highlights the need for better implementation strategies and patient-centred education to improve adherence to care. 
References:
- Liu C et al. Association between metabolic syndrome and cataract: a meta-analysis. Eye (2025) 39:2555–2564; https://doi.org/10.1038/s41433-025-03910-2.
- Afflitto GG et al. Cataract and Risk of Fracture A Systematic Review, Meta-Analysis, and Bayesian Network Meta-Analysis. Ophthalmology Volume 132, Number 8; 921-934. August 2025. https://doi.org/10.1016/j.ophtha.2025.02.010.
- Al-Swailem S et al. Immediate Versus Delayed Sequential Bilateral Cataract Surgery: A Systematic Review. Clinical Ophthalmology 2026:20 581259. https://doi.org/10.2147/OPTH.S581259.
- Anguas MG et al. Cataract care process: Systematic review of clinical guidelines and synthesis of recommendations. J Healthc Qual Res 2025 Nov-Dec;40(6):101161. doi: 10.1016/j.jhqr.2025.101161. Epub 2025 Sep 29.