Abstract
BackgroundTo compare different K readings in pseudophakic patients post-Descemet’s stripping automated endothelial keratoplasty (DSAEK) and evaluate corresponding prediction errors in intraocular lens (IOL) power calculations.MethodsSubjects that underwent cataract surgery and DSAEK surgery at least 3 and 6 months prior, respectively, and IOL implantation in the capsular bag were included in this study. Manifest refraction and IOL information were recorded. A Scheimpflug keratometer (Pentacam) was used for corneal measurements, including the mean anterior and posterior radii of curvature, simulated keratometer (SimK), true net power (TNP), and equivalent K reading (EKR) at the 4.0-mm zone. Conventional keratometry was acquired using the IOLMaster (KMaster). The four K measurements were evaluated for calculating the predicted refraction.ResultsThe study included 20 eyes from 19 subjects. The ratio of the posterior to the anterior corneal radius was 74.1 ± 3.24%. Comparison of the four keratometric methods (KMaster, SimK, EKR, and TNP) revealed statistically significant differences among all the methods besides KMaster and SimK. Of the four IOL calculation methods(KMaster, SimK, EKR and TNP method),the arithmetic prediction error of the KMaster, SimK, and EKR methods featured nonsignificant differences from zero(p = 0.07, 0.19 and 0.84 respectively); the EKR method calculated the highest percentage of eyes with IOLs within the prediction error.ConclusionsIOL calculations in post-DSAEK eyes using KMaster, SimK, and EKR can yield small refractive errors after surgery. The EKR (4.0-mm diameter) method was found to be the most accurate.
Highlights
To compare different K readings in pseudophakic patients post-Descemet’s stripping automated endothelial keratoplasty (DSAEK) and evaluate corresponding prediction errors in intraocular lens (IOL) power calculations
Considering that the mean value of the absolute prediction error of the equivalent K reading (EKR) method was the lowest (EKR, 0.74; simulated keratometer (SimK), 0.82; keratometry was acquired using the IOLMaster (KMaster), 0.89), we suggest that EKR be used in IOL calculations in post-DSAEK eyes
The present study found that the arithmetic prediction error of KMaster and SimK was not significantly different from zero, indicating that laser-assisted in situ keratomileusis (LASIK) and DSAEK both change the relationship between the anterior and posterior corneal refractive powers, the latter induces a smaller impact on corneal refractive power than does the former
Summary
To compare different K readings in pseudophakic patients post-Descemet’s stripping automated endothelial keratoplasty (DSAEK) and evaluate corresponding prediction errors in intraocular lens (IOL) power calculations. Accurate assessment of the total corneal power of eyes following corneal refractive surgery is essential for determining optimal intraocular lens (IOL) power, and the difficulties in accurately evaluating corneal power after laser-assisted in situ keratomileusis (LASIK) have been well described [1, 2]. Descemet’s stripping automated endothelial keratoplasty (DSAEK) procedure is a lamellar corneal surgical technique used to replace the abnormal corneal endothelium of patients with endothelial disease [3]. The present retrospective study aimed to compare K readings obtained with a conventional keratometer (IOLMaster) and a Scheimpflug keratometer in pseudophakic, post-DSAEK patients to evaluate prediction errors in IOL power calculations Xu et al BMC Ophthalmology (2018) 18:268 those of control or pre-DSAEK groups [7,8,9,10,11]; data on the accuracy of K measurements in post-DSAEK corneas and the prediction error in IOL power calculations among post-DSAEK patients is lacking.
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