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Year : 2022  |  Volume : 2  |  Issue : 1  |  Page : 35-39

Evaluation of prediction accuracy of Barrett Total Keratometry Universal II formula using swept-source optical biometry

Department of Ophthalmology, Visakha Eye Hospital, Visakhapatnam, Andhra Pradesh, India

Correspondence Address:
Dr. Surekha Mannem
MBBS, DNB Ophthalmology. H.No. 45A-3-8, Aadishankara Nilayam, Palakol, West Godavari District, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jocr.jocr_8_22

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Purpose: The purpose of this study was to evaluate the prediction accuracy of Barrett Total Keratometry (TK) Universal II formula using swept-source optical coherence tomography (SS-OCT)-based optical biometer. Materials and Methods: One hundred and thirty-five eyes of 135 patients from Visakha Eye Hospital, Visakhapatnam, India, were prospectively enrolled in this study. Ocular parameters were measured using IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany). Emmetropic spherical equivalent intraocular lens (IOL) power was calculated with Barrett TK Universal II formula using TK and Sanders–Retzlaff–Kraff (SRK)/T formula using standard keratometry. Selected IOL power and predicted refractive errors were recorded. Postoperative manifest refraction was measured at 1 month. Absolute prediction errors (APEs), mean absolute error (MAE), median absolute error (MedAE), and percentage of eyes within ± 0.25, ±0.50, and ±1.00 D of predicted refraction were calculated for each formula. Results: Barrett TK Universal II formula using TK values showed low APEs, MAE, and MedAE. There were a higher percentage of eyes with APE within ±0.25, ±0.50, ±0.75, and ±1.00 D. This formula gave better results when compared to SRK/T formula using K value. However, it was not statistically significant. Conclusion: IOL power calculation using SS-OCT-based optical biometer and Barrett TK Universal II gives better results with the least APE and using TK provides superior refractive outcomes which would be beneficial for the patients undergoing phacoemulsification with toric or multifocal IOLs.

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