As toric lenses are becoming a more frequently used lens rather than solely as a premium product, the costing and need of such an item has become important. In light of this issue, Dr Mohammed Muhtaseb and Dr Mohammad Khan recently published the results of their study analysing and quantifying the need for toric lenses in cataract patients awaiting surgery in an NHS hospital.

"We were interested in understanding our patient demographic in greater detail so as to establish the need for toric lens provision. We could then plan its probable cost and implementation," said Dr Muhtaseb, previous consultant ophthalmologist at the Singleton Hospital Abertawe Bro Morgannwg University NHS Trust, Swansea, UK.

Compiling the study

The crosssectional study included 1230 eyes of 746 patients from the NHS teaching hospital in Swansea. All patients had their keratometric measurements recorded over a 4-month period at a preassessment clinic and the results were prospectively gathered and analysed. To establish a pattern of corneal astigmatism Dr Muhtaseb explained that data from all patients presenting at the centre was collected over a sufficiently protracted time period.

At the time of cataract surgery a toric IOL (Rayner TFlex, UK) was implanted to correct for the corneal astigmatism. "We did not consider analysing wavefront errors or other data," added Dr Muhtaseb, "Our focus was on the main element of a patient's clinical picture that we could treat and that would greatly affect the quality of the surgical outcome."

There were minimal factors affecting the results. Dr Mohammed explained. "All patients were seen in the same department by one of the same four technicians, all using the same model of IOL Master, and all patients had surgery using the same model of phacoemulsification device (Storz Millennium)."

Beneficial to hospitals

The measured corneal astigmatism of the majority of the study group (79.5%) was 1.5 D or less. A little less than a quarter of the patients involved in the study had a corneal astigmatism of 0.5 D or less and only about 6.5% of the patients had a corneal astigmatism of more than 1.5 D. This data will prove useful to hospitals in determining the level of need for toric IOLs and how much it will cost to implement the use of these lenses in this setting.

"The data from this study shouldn't only be confined to NHS practices," according to Dr Muhtaseb. "These findings will also benefit patients being treated in private practice." He noted that further clinical data from a greater patient population and using a dedicated corneal topographer could offer a more clinically 'ideal' situation to this type of study, however, the IOLMaster was used as it is practical and relevant to a real-life scenario for many surgeons. In the future, Dr Muhtaseb would like to proceed with a further study of the clinical outcomes and patient satisfaction after toric IOL implantation.

"We hope, however, that our study has added weight to the currently available literature that supports the use of toric IOLs through demonstrating the need for them," concluded Dr Muhtaseb.