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Klin Monbl Augenheilkd 2023; 240(05): 683-688
DOI: 10.1055/a-1583-9723
Klinische Studie

Influence of Posterior Corneal Asphericity on Refractive Error of SRK-T and Barrett Formulas for Lucidis IOL

Einfluss der posterioren Hornhautasphärizität auf den Refraktionsfehler der SRK-T- und Barrett-Formeln für Lucidis IOL
Mark Rabinovich 
Ophthalmology, Clinique de lʼOeil Onex, Onex, Switzerland
,
Ana Maria Aramburu Del Boz
Ophthalmology, Clinique de lʼOeil Onex, Onex, Switzerland
,
Daniel Al-Khatib
Ophthalmology, Clinique de lʼOeil Onex, Onex, Switzerland
,
Jean Pascal Genestier
Ophthalmology, Clinique de lʼOeil Onex, Onex, Switzerland
,
Jerome Bovet
Ophthalmology, Clinique de lʼOeil Onex, Onex, Switzerland
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Abstract

Purpose To evaluate the influence of posterior corneal asphericity on the refractive error using SRK-T and Barrett formulas for the intraocular lens (IOL) power calculation for Lucidis Extended Depth of Focus (EDOF) IOL.

Setting This study was carried out at a tertiary ophthalmology center in Geneva, Switzerland.

Design A retrospective study. Medical records from all enrolled patients were analyzed and the following information was extracted retrospectively, over 1 month following surgery.

Methods We retrospectively reviewed 75 eyes that underwent cataract surgery and were implanted with a Lucidis EDOF IOL. We measured the posterior corneal asphericity (Q value), axial length (AL), and anterior chamber depth (ACD) and then calculated the IOL power using SRK-T and Barrett formulas.

Results Seventy-five eyes were included, all of which had 1-month postoperative data. In the cohort, 32 eyes were from females (43%) and 43 from males (57%). The mean age of the study population was 73 ± 8.8 years. The mean AL was 23.5 ± 0.98 and the mean ACD was 3.13 ± 0.3. The mean posterior Q value was − 0.35 ± 0.2. In a regression analysis, we found a statistically significant relationship between the error in refraction prediction and the posterior Q value, irrespective of the formula used. The relationship between posterior corneal asphericity and the refraction prediction error was stronger for the Barrett II Universal formula than for the SRK-T formula.

Conclusions Posterior corneal asphericity was correlated with the refractive error of calculation of both SRK-T and Barrett formulas, with a stronger correlation to the latter formula.

Zusammenfassung

Ziel Den Einfluss der posterioren Hornhautasphärizität auf den refraktiven Fehler der mit SRK‑T- und Barrett-Formeln kalkulierten Intraokularlinsenberechnungen (IOL-Berechnungen) für Lucidis-Extended-Depth-of-Focus-Intraokularlinsen (EDOF: Extended Depth of Focus) zu evaluieren.

Ort Diese Studie wurde in einem Tertiärzentrum für Augenheilkunde in Genf, Schweiz, durchgeführt.

Design Eine retrospektive Studie. Die Gesundheitsakten aller in die Studie aufgenommenen Patienten wurden analysiert; die Daten für den 1. Monat nach der Operation wurden retrospektiv extrahiert.

Methoden Es wurden 75 Augen nach Kataraktoperation mit Implantation einer Lucidis-EDOF-IOL retrospektiv überprüft. Wir haben die posteriore Hornhautasphärizität (Q-Wert), axiale Länge (AL) und Vorderkammertiefe (VKT) gemessen; die IOL-Berechnung wurde mit den SRK‑T- und Barrett-Formeln durchgeführt.

Ergebnisse Es wurden 75 Augen in die Studie aufgenommen. Für alle Augen lagen die postoperativen Daten für den 1. Monat nach der Operation vor. In dem Patientenkollektiv waren 32 Augen von Frauen (43%) und 43 von Männern (57%). Das Durchschnittsalter der Studienpopulation betrug 73 ± 8,8 Jahre. Die durchschnittliche AL betrug 23,5 ± 0,98 und die mittlere VKT betrug 3,13 ± 0,3. Der durchschnittliche Q-Wert der hinteren Hornhautfläche betrug − 0,35 ± 0,2. Bei der Regressionsanalyse fanden wir eine statistisch signifikante Beziehung zwischen dem refraktiven Vorhersagefehler und dem Q-Wert der hinteren Hornhautfläche, ungeachtet der für die Berechnung verwendeten Formel. Die Verbindung zwischen posteriorer Hornhautasphärizität und refraktivem Vorhersagefehler war mit der Barrett-Universal-II-Formel stärker als mit der SRK‑T-Formel.

Schlussfolgerungen Die posteriore Hornhautasphärizität korrelierte sowohl mit dem mit der SRK‑T-Formel als auch mit dem mit der Barrett-Formel kalkulierten refraktiven Fehler, wobei die Korrelation mit der letztgenannten Formel stärker ausgeprägt war.

What was known

  • Anterior corneal asphericity is one of the possible sources of IOL power calculation errors.

  • There is a correlation between the posterior corneal curvature and IOL power underestimation.


What this paper adds

  • When using either the Barrett or SRK-T formula for the IOL power calculation for the Lucidis EDOF IOL, there is a refractive error that is correlated to the posterior corneal asphericity.

  • Posterior corneal asphericity influences the refractive outcomes for the Lucidis EDOF IOL.

  • Using either the Barrett or SRK-T formula for the IOL power calculation, a prolate corneal shape can lead to a myopic prediction, whereas an oblate corneal shape can lead to a hyperopic prediction.

Key words

cornea - asphericity - Lucidis - cataract - IOL - EDOF - SRK-T - Q value - Barrett - corneal asphericity

Schlüsselwörter

Hornhaut - Asphärizität - Lucidis - Katarakt - IOL - EDOF - SRK-T - Q-Wert - Barrett - korneale Asphärizität


Publication History

Received: 19 May 2021

Accepted: 04 August 2021

Article published online:
17 September 2021

© 2021. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

 

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