Audit Of The Use Of A Cataract Complexity Grading Tool In Cataract Pre-Assessment Clinics In A United Kingdom Teaching Hospital

There are multiple stratification scoring systems for cataract surgery, including the Muhtaseb score, Buckinghamshire score, and more recently the tool developed by Nderitu et al. Such tools allow for improved patient safety and case allocations to appropriately skilled surgeons, and improves trainee confidence by allowing them to take on suitable cases.

A cataract complexity grading tool was developed and introduced in May 2023 at our hospital to facilitate patient assessment in cataract clinics and improve case allocations to consultants and trainees with varying levels of experience.

This audit aims to assess the compliance to and accuracy of this grading tool in cataract pre-assessment clinics.

The study took place in a single hospital in the UK.

The grading tool classified cataract cases as simple (grade A), intermediate (grade B), and complex (grade C), based on patient age, biometry readings, cataract density, pupil dilation, use of alpha-agonists, past ophthalmic history and patient factors. Risk factors were considered equally to stratify cases, rather than attributing different scores to individual risk factors as is the case in other grading tools.

Data was collected retrospectively from electronic records for 6 consecutive cataract lists in May 2023 and 5 lists in September 2023. Cataract pre-assessment clinic entries and biometry results were reviewed and audited against the grading tool. Intraoperative notes were reviewed for any missed pre-operative findings or unexpected findings. The accuracy of the pre-operative assessor’s grading was then audited against the grading criteria.

Data collected included cataract density, pupil dilation, ophthalmic co-pathologies, level of vision in the non-operative eye, use of alpha-agonists, biometry data, and complications and comments from cataract surgery in the first eye (including intraoperative floppy iris syndrome) where applicable.

53 cases involving 13 graders were audited. 14(26.4%) were grade A, 18(34.0%) grade B, and 21(39.6%) grade C.

32(60.4%) cases were appropriately graded based on the set criteria. Of the remaining 21 cases, 8 graders were involved and 9(17.0%) cases were graded as more complex and 12(22.6%) cases as less complex than the set criteria with no documented rationale.

Only 15(28.3%) cases had pupil size documented. 2 cases, both identified pre-operatively, required the use of pupil expansion devices. 

6/11 audited lists only comprised grade B/C cataracts. A total of 17(32.0%) cases were performed by a trainee or specialty doctor. Of those, 6 were grade A, 7 grade B, and 4 grade C.

None of the audited cases were complicated by a PCR or vitreous loss.

The grading tool provides a framework in cataract clinics and allows for better case allocation when used appropriately. However there is poor documentation of pupil size, which has been shown to be a significant risk factor for intraoperative complications by Nderitu et al. The rationale for the selected grade was also not always clear. The use of a proforma would help standardise documentation.

Lists including only higher grade cataracts may impede training. The current grading tool does not consider higher levels of complexity attributed to certain factors such as white cataracts. Other tools allow for more accurate scoring by individually scoring risk factors. This strategy would allow for better case mix allocation on training lists.