Pattern of Preoperative Astigmatism in Patients in South East Nigeria as Determined by Biometry

Background: Astigmatism is an error of refraction that can affect visual outcome after cataract surgery. The degree of astigmatism is usually estimated pre-operatively by keratometry readings. These readings can help in the plan of surgical technique and choice of intraocular lenses during cataract surgery in order to improve visual outcome. This study was done to provide data on the pattern of preoperative astigmatism in cataract patients in South East Nigeria. It is hoped that this knowledge will increase the awareness on pre-operative astigmatism among ophthalmologist so that they can improve their surgical skills on ways of reducing this astigmatism or avoid worsening it.

Methods: A retrospective review of keratometry readings of 533 patients were taken from June 2018 to December 2019, with emphasis on the cylinders.

Results: The most common degree of astigmatism was -0.75DC. The proportion of patients with preoperative astigmatism ≤ -1.00DC was 60% while 40% had values higher than -1.00DC.

Conclusion: There may usually be significant pre-operative astigmatism in patients scheduled for cataract surgery. This calls for an improvement in surgical skills in minimizing astigmatism and avoiding worsening preoperative astigmatism. There should be increase availability and use of toric lenses for correction of preoperative astigmatism. Finally accurate postoperative refraction will have a positive impact in the management of astigmatism, whether preoperative or surgically induced.