The importance of biometry to cataract outcomes in a surgical unit in Africa.

PURPOSE: To determine how much difference biometry makes to refractive outcomes in a population in Sub-Saharan Africa compared to using standard-power intraocular lenses (IOLs).

METHODS: In a secondary eye-clinic in Kenya, IOL-powers in half diopters (D) were implanted according to biometry prediction in patients undergoing routine cataract surgery with small-incision techniques. A model was generated to predict refractive outcomes if standard-IOLs had been used.

RESULTS: Three-hundred-twenty-five eyes of 290 patients were operated on; 232 (71%) using phacoemulsification, the remainder using manual small-incision cataract surgery. Two-hundred-sixty-seven eyes (82.2%) achieved corrected visual acuity (VA) >or=6/18 and 202 eyes (62%) uncorrected VA >or=6/18. Pre-existing comorbidity was the single most common reason for a worse postoperative VA. Restricting analysis to one eye per patient, with biometry 71.1% had a good refractive outcome (defined as +1 to -1.5 D spherical equivalent), 27.6% became more than -1.5 D myopic and 1.3% more than +1.00 D hyperopic. With standard-power-IOLs 57.3% would have had a good refractive outcome and 16% would have become >1 D hyperopic. Using the post-op refractive data for A-constant optimization could potentially further increase good refractive outcomes to over 80%.

CONCLUSION: Biometry in combination with small-incision techniques improves refractive outcomes and decreases undesired postoperative hyperopia. Assuming good surgical skills, better outcomes with biometry justify cataract operation at an earlier stage, thereby reducing intra- and postoperative complications and avoiding years of visual disability.