Presence of a soft contact lens during biometry

Abstract

A case of an intraocular lens (IOL) power calculation error due to the presence of a soft contact lens (CL) is described. During preparation of a routine cataract surgery for a patient in the operating room, a soft CL was discovered on the patient’s surgical eye by the scrub nurse. Further, questioning revealed that the patient was a regular CL wearer and had possibly worn them during pre-operative biometric measurement, suggesting a potential error in his IOL calculation. Surgery was not performed, and the patient was given a CL holiday. Examination of the pre-operative B-scan ultrasound by the IOL Master700 confirmed the presence of the soft CL. Four weeks after the CL holiday, re-measurement of the surgical eye with the same biometric formula, lens factor and post-operative visual target revealed a +6.00 dioptre difference in the recommended lens implant. The patient underwent cataract extraction and IOL implantation with the correct IOL implant, with a good visual outcome. Presence of a CL during biometry causes a significant error in the IOL power calculation and should be identified preoperatively for this very common surgery.