A clinical audit can provide many benefits in a busy practice, from improving outcomes to optimising workflow. An audit is typically conducted to address a single question or problem.
Dr Imran Yusuf, a Clinical Research Fellow from the Oxford Eye Hospital, UK, gave an interesting presentation on optimising workflow and audit of postcataract astigmatism during the ESCRS Virtual Winter Meeting.
He noted a clinical audit is a systematic process involving an evaluation against predefined criteria, followed by proposals for change and re-audit to assess their impact.
Various European studies have shown a significant prevalence of pre-existing corneal astigmatism in cataract patients, with approximately 20% having more than 1.5 D of corneal astigmatism. This is a sizable number considering the large number of cataract surgeries performed.
The significance of 1.5 D as a threshold for considering toric IOLs is explained well in a study by Schallhorn (et al, 2021) that examined more than 15,000 individuals undergoing cataract and refractive lens exchange. This study concluded that with 1.5 D of residual refractive astigmatism, the odds of achieving 20/20 vision drops from around 84% to less than 10%. The chance of achieving 20/16 drops from about 50% to essentially zero. The study also concluded that postoperative astigmatism results in significantly decreased patient satisfaction. Dr Yusuf noted this particular result might be even more significant than the reported study, using validated visual function questionnaires and other tools.
Surgeons, too, demand excellent outcomes, and auditing these outcomes is essential in driving improvement. “You can’t improve what you don’t measure!” Dr Yusuf said. As he explained, the aims of astigmatism correcting surgery are to reduce/eliminate refractive astigmatism and spectacle dependence for the target distance, ideally in one procedure, with very few or no complications.
Large data sets such as EUREQUO, UK National Ophthalmology Database, and Swiss registries have not set any clear benchmarks for these aims and how often these are expected to be achieved.
Definition of standards must be the starting point for any audit, with different surgical techniques that tackle astigmatism assessed separately. Differences such as digital versus manual marking, femtosecond laser versus manual surgery, IOL technology type, presence or absence of ocular comorbidities - all may need separate auditing. Cohorts may differ in the magnitude of pre-existing corneal astigmatism, visual expectations, and the proportion of resident-performed operations.
“Published data can help establish benchmarking,” Dr Yusuf said. However, differences in data reporting are common between studies. Without standardised methods of reporting, aggregating data and benchmarking from small clinical studies is challenging. Access to “Big Data” is essential to assess certain surgical outcomes. For example, a study of 6,000 eyes from the American Academy of Ophthalmology Iris Registry found the surgical repositioning rate was 1.3%, with IOL design and patient age identified as significant risk factors for increased rates of surgical repositioning. Smaller studies report a repositioning rate up to 9%.
Some obvious benchmarks to include in any minimum data set are parameters for efficacy (unaided distance visual acuity and residual refractive stigmatism), safety (corrected distance visual acuity; complication rate, misalignment, and repositioning rates), spectacle independence, and patient satisfaction. However, any minimum data set for astigmatic correction in cataract surgery needs to be agreed through a consensus between key stakeholders, including surgeons and patient advocates.
Data flows are also relevant factors to consider in an audit. Electronic medical record systems help greatly to automate data entry and analysis. These systems can provide meaningful data sets since they integrate outcomes and audits into routine clinical practice by allowing digital entries of all meaningful outcome measures. Data can then be continuously audited within the service—either against one’s own outcomes, against the whole service, or against external sources—which further help refine standards because of the greater number of patients included.
Dr Yusuf stressed again in his conclusion the need for large data sets to support clinical audit in managing astigmatism in cataract surgery, clarity on the minimum data set required, standardisation of outcome measures to allow comparison between studies, and continuous digital data capture to facilitate real-time analysis.
“A minimum meaningful data set should be defined with a compromise between what is important in terms of an outcome measure and what is practical to gather, especially in high volume practices where it may be difficult to gather large volumes of information on all patients,” he advised.
Dr Imran H Yusuf MBChB(Hons), MRes, MRCP(UK), PG Dip Ed, DPhil, FRCOphth is a Clinical Research Fellow at Oxford Eye Hospital and the University of Oxford, UK.
imran.yusuf@eye.ox.ac.uk
Dr Soosan Jacob is Director and Chief of Dr Agarwal’s Refractive and Cornea Foundation t Dr Agarwal’s Eye Hospital, Chennai, India, and can be reached at
dr_soosanj@hotmail.com