ESCRS - FP30.06 - Stratification Of Cataract Patients According To Their Ocular Biometry: How Rare Is The Rare Eye?

Stratification Of Cataract Patients According To Their Ocular Biometry: How Rare Is The Rare Eye?

Published 2024 - 42nd Congress of the ESCRS

Reference: FP30.06 | Type: Free paper | DOI: 10.82333/qfdr-qa71

Authors: Marta Jiménez-García* 1 , Martín Puzo Bayod 2 , Galadriel Gimenez Calvo 3 , Francisco J. Castro Alonso 4

1GIMSO Ophthalmology,Instituto de Investigación Sanitaria de Aragón,Zaragoza,Spain;Física Aplicada–Área Óptica,Universidad de Zaragoza,Zaragoza,Spain;Unidad de Cirugía Faco-Refractiva,Hospital Nuestra Señora de Gracia,Zaragoza,Spain, 2GIMSO Ophthalmology,Instituto de Investigación Sanitaria de Aragón,Zaragoza,Spain;Unidad de Cirugía Faco-Refractiva,Hospital Nuestra Señora de Gracia,Zaragoza,Spain, 3Unidad de Cirugía Faco-Refractiva,Hospital Nuestra Señora de Gracia,Zaragoza,Spain;Física Aplicada–Área Óptica,Universidad de Zaragoza,Zaragoza,Spain, 4GIMSO Ophthalmology,Instituto de Investigación Sanitaria de Aragón,Zaragoza,Spain;Unidad de Cirugía Faco-Refractiva,Hospital Nuestra Señora de Gracia,Zaragoza,Spain;Cirugía,Universidad de Zaragoza,Zaragoza,Spain

Purpose

To evaluate the distribution of ocular biometric parameters acquired using a Swept Source technology-based optical biometer (IOL Master 700, Zeiss) and to determine the distribution patterns and frequencies of their combinations, particularly of those that can be considered extreme or unusual.

Setting

Monocentric study in a high-resolution cataract surgery unit.

Methods

Retrospective descriptive study. Data of 20,004 patients without previous corneal surgery was acquired in 2016–2022. Descriptive statistics were calculated for axial length (AL), anterior chamber depth (ACD), lens thickness (LT), mean anterior keratometry (Km), white to white (W2W), and anterior segment (AS). The values of those parameters were stratified into “Standard”, “High” or “Low” based on their average value and standard deviation (SD). The limits for “Standard, Std.”, “High” and “Low” were set at mean±0.5SD, mean+SD and mean-SD respectively. “Extreme” included eyes above “High” and below “Low” limits. Parameters were coupled (e.g. LT vs ACD) and the frequencies of their combinations (e.g. High LT & High ACD) evaluated.

Results

Only 1% of the eyes presented [LowAL<22.2mm  & LowKm<42.5D] or [High AL (>24.8mm)  & High Km (>45.5D)]. Among the StdAL eyes [22.82–24.13mm], 12.5% presented extreme ACD (<2.64 or >3.43mm), 14.6% extreme LT(<4.10 or >5.02mm) and 13.5% extreme AS (<7.2mm or >8mm).

12.2% of eyes presented extreme ACDs with stdKm [43.3–44.8D], 11.9% extreme Km with stdACD [2.84–3.23mm], 37.4% of eyes had both ACD & Km out of the std. range, suggesting inferring ACD from Km (or vice versa) is not accurate. Similar values are found when pairing Km & AS.

1.5% of eyes presented [High ACD & Low AS] or [Low ACD & High AS]. 12% of the eyes had Low-High or High-Low  combinations of Km and W2W.

Conclusions

This study illustrates the diversity in ocular biometric parameters and their interplays, highlighting the intricate nature of ocular biometry. Furthermore, it underscores the importance of bespoke IOL calculation methods, as standard formulas often fall short for eyes with atypical biometric values, especially when multiple extreme values coexist. Those eyes that fall outside the expected range pose a challenge to predictive models that utilize a single parameter to estimate another. The conclusions drawn here question the traditional reliance on normative data to anticipate ocular dimensions.