Title : Refractive outcomes in phacoemulsification surgery for small eyes
Abstract:
Background: Cataract surgery is the most commonly performed elective surgery in the UK with more than 400,000 operations done each year. They aim to improve vision by restoring a clear intraocular lens. Patients with smaller eyes have a higher risk of intra- and post-op complications and generally pose a deeper surgical challenge to medical professionals. Consequently, postoperative refraction is more difficult to predict in short eyes using current popular intraocular lens formula. This research aims to look at the impact of axial length on refractive outcomes and provide a comparison on the results obtained from different intraocular lens formulae used.
Method: Data was collected from all cataract surgeries performed by a consultant ophthalmologist and his team in the Queen Elizabeth Hospital, Birmingham between June 2014 to June 2024. Records were retrieved from Medisight and analyzed in the department. Analysis was based on two subsets: axial length: 20-21.9mm and axial length ≥ 22mm. The proportions of the different intraocular lens formulae used in each subset was calculated, with a predominance of Hoffer Q and SRK/T being implemented. Data was compared to the UK benchmark standards for post-op refraction and analysed against other systematic reviews conducted.
Results: Eyes with an axial length of 20-21.9mm did not achieve the UK benchmark standard for post-op refraction of 55% within +/-0.5SD and 85% within +/-1SD. Small eyes achieved 52% within +/-0.5SD and 79% within +/-1SD. This reflects the challenges in intraocular lens calculation for small eyes. This compares to eyes with an axial length of ≥22mm that resulted in outcomes of 56% within +/-0.5SD and 88% within +/-1SD. Overall for all cataract surgeries performed the benchmark standard was met at 56% within +/-0.5SD and 87% within +/-1SD. With regard to the intraocular lens formulae used, only Hoffer Q achieved the UK benchmark at both standard deviations whereas SRK/T only achieved it at +/-1SD.
Conclusion: Overall, expected refractive outcomes in small eyes did not meet UK benchmarks for +/-0.5SD and +/-1SD. Further formula analysis is required to meet UK benchmark outcomes for +/-1SD in small eyes. Hoffer Q was the only intraocular lens formula used in the study which achieved the UK benchmark at both standard deviation intervals.
