Abstract
Purpose: :
Intraocular lens (IOL) power calculation using the IOL Master requires fixation. Mydriasis may cause loss of fixation to some degree. The aim of this study was to evaluate biometric parameters in IOL Master examination before and after mydriasis.
Methods: :
Patients pre-cataract surgery underwent an IOL master examination pre and post mydriasis. Exclusion criteria were mydriasis <5.5 mm, macular edema or hemorrhage, corneal pathology influencing keratometric (K)values, eyes post trauma/intraocular surgery, inability to fixate and best corrected visual acuity <20/100 pre-dilatation. criteria.
Results: :
Following approval of IRB, 101 eyes were included (73 patients). The average ±Standard deviation (SD) AL and K values differences (pre - post dilatation) were -0.0011 ±0.03901mm and -0.028 ±0.5647 diopters (D) respectively. Right eyes were found with an average ±SD AL and K values difference of -0.0077 ±0.037 mm and 0.002 ± 0.169 D respectively. Left eyes’ average AL and K values difference were 0.005 ±0.04 mm and -0.056 ± 0.772 D respectively. Eyes of males had an average ±SD AL and K values difference of -0.0055 ± 0.055 mm and -0.0828 ± 0.8566 D respectively, while in females average AL and K values difference were 0.0018 ± 0.0226 mm and 0.009 ± 0.205 D respectively.
Conclusions: :
The average AL differences in our study was <0.1 mm and average K values <1 in all groups, thus not clinically significant. This implies that an IOL Master examination can be done pre and post mydriasis without a clinically significant change in the calculated IOL power.
Keywords: intraocular lens