ESCRS - PP19.04 - Reproducibility And Repeatability Of Corneal Topography Measured By Two Placido-Based Corneal Topographers With And Without Swivel-Out Configuration (Atlas 500, Atlas 9000)

Reproducibility And Repeatability Of Corneal Topography Measured By Two Placido-Based Corneal Topographers With And Without Swivel-Out Configuration (Atlas 500, Atlas 9000)

Published 2026 - 44th Congress of the ESCRS

Reference: PP19.04 | Type: Free paper | DOI: 10.82333/mtrx-yx74

Authors: Dr Paz Paz Orts-Vila* 1 , Dr Pedro Tañá-Sanz 1 , Dr Santiago Tañá-Sanz 1 , Mrs Maria Ramos 1 , Mrs Cristina Tello-Elordi 1 , Dr Pedro Tañá-Rivero 1

1Oftalvist Alicante,Alicante,Spain

Purpose

To compare repeatability, reproducibility, and agreement of the Placido-based ATLAS 500 topographer (using straight and swivel-out configurations) with its predecessor, ATLAS 9000 in normal eyes

Setting

Oftalvist Alicante, Spain

Methods

This prospective study included 100 healthy eyes of 100 patients without ocular comorbidities.  Block-randomized consecutive measurements were obtained using two Placido-based corneal topographers (ATLAS 500, ATLAS 9000, Carl Zeiss Meditec, Jena, Germany) by two experienced operators. ATLAS 500 measurements were acquired in straight and swivel-out configuration to evaluate difference in corneal coverage. Each patient underwent 18 scans (2 operators × 3 scans x 3 configurations). Corneal power, astigmatism magnitude, WTW distance, corneal aberration, and Placido coverage area were recorded. Repeatability, reproducibility, inter-device agreement, and inter-rater reliability were analyzed using random-effects ANOVA and Bland Altman analysis.

Results

ATLAS 500 demonstrated lower repeatability standard deviations than ATLAS 9000 for K1 (0.025 vs. 0.062), K2 (0.023 vs. 0.058), astigmatism (0.015 vs 0.018). ATLAS 500 exhibited substantially lower coefficient of variation than ATLAS 9000 for K1 (0.06% vs. 0.15%), K2 (0.05% vs. 0.13%) and astigmatism (1.53% vs. 1.84%). Bland–Altman analysis revealed no significant difference between devices for K1/K2. ATLAS 500 showed smaller within-patient variations and greater inter-operator consistency than ATLAS 9000. Both configurations of ATLAS 500 demonstrated comparable, moderate agreement with ATLAS 9000 for keratoconus classification, with the swivel-out configuration providing marginally higher consistency.

Conclusions

ATLAS 500 showed measurement precision comparable to or better than ATLAS 9000, with strong intra-device repeatability and broader corneal coverage in the swivel-out configuration, supporting its use for placido-based corneal topography in routine cornea refractive assessment.