The multicentre, retrospective study found that using LAF or HEPA filtration for cataract surgery offered no infection reducing benefit. File photograph used for representational purposes only
A study across the various units of a premier eye care hospital in southern India has found that using advanced air filters in operation theatres offers no added benefit to infection prevention in cataract surgery. The study, Comparison of Cataract Surgery Endophthalmitis Rates in Operating Rooms with and without Laminar Air Flow and HEPA Filters, authored by Sheena Song, David F. Chang et al., was published in the American Journal of Ophthalmology in August.
Aravind Eye Care System (AECS), which has a network of 14 regional hospitals in south India, performs around 50% to 60% of cataract surgeries on indigent patients at little or no cost to the patients.
AECS system has operating rooms of varying types depending on the hospital location and its age. Since the hospital has standardised surgical protocols, antibiotic prophylaxis, instrument processing and environmental safety across its units, it decided to examine if installation of laminar air flow (LAF) and high efficiency particulate air filters would reduce the rates of postoperative endophthalmitis (POE).
POE is a complication that can occur after cataract surgery. Infection is mainly due to invasion of the globe by microbial flora, bacteria, or fungi from the adnexa (structures surround and support the eye ball) and environment during the surgery If not treated promptly, it could lead to vision loss.
The study
Researchers at ACES conducted a retrospective study of the 4,52,770 cataract surgeries performed at its 14 hospitals in India in 2023.
“The retrospective analysis reviewed the cataract surgeries, all performed using identical surgical and infection-control protocols, including periocular povidone-iodine and intracameral moxifloxacin. Surgeries were performed in operating rooms with varying air-handling units: LAF with HEPA, central AC with HEPA, central AC without HEPA, and split AC without HEPA,” explained R. Venkatesh, chief medical officer at Aravind Eye Care Hospital in Puducherry and one of the authors of the study.
The multicentre, retrospective study, found that using LAF or HEPA filtration for cataract surgery offered no infection reducing benefit.
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Across all groups, the overall POE rate was extremely low at 0.016%, with no statistically significant differences between the different ventilation systems—even when analysed separately by surgical method: phacoemulsification vs manual small incision cataract surgery MSICS or patient category: paying vs non-paying, the researchers said.
“This contradicts mandating these more expensive air handling unit systems for ophthalmic surgery. Recommending or requiring LAF or HEPA unnecessarily imposes additional infrastructural barriers for ophthalmic operating rooms in resource-limited settings and for office-based surgery in high-income countries,” the study concluded.
Towards safe surgeries
The study noted that the results of the analysis showed that safe cataract surgery is achievable without an expensive LAF or HEPA system, provided rigid aseptic protocols are followed.
“This could remove unnecessary infrastructure barriers in resource-limited settings and make cataract surgery more accessible across all types of surgical facilities worldwide,” said Dr. Venkatesh.
A similar result came up in an earlier study conducted nearly a decade ago. That study was conducted by Shalinder Sabherwal of the Department of Community Ophthalmology and Public Health Research at Dr. Shroff’s Charity Eye Hospital, New Delhi.
Dr. Sabherwal, Deepali Chaku et al. had published their findings in the Indian Journal of Ophthalmology in May 2020, based on their analysis of surgery outcomes for five years between 2013 and 2018. The study, published as the article Are high-efficiency particulate air (HEPA) filters and laminar flow necessary in operating rooms to control acute post-operative endophthalmitis? relied on a retrospective analysis of medical records of 88,297 cataract surgeries conducted in a single network of a tertiary and four secondary hospitals across north India. It identified cases of endophthalmitis from the records between January 2013 and June 2018.
The analysis found that the incidence at secondary centres, without LAF and HEPA filters, were comparable to that found in the tertiary centres with these facilities.
(R. Sujatha is an independent journalist based in Chennai. sujatha.raghunath@gmail.com)
Published – September 06, 2025 12:17 pm IST