Evaluation Of The Repeatability Of The Anterior Segment Camera According To The Topographical Position Of The Cornea In Keratoconus Patients
Published 2024 - 42nd Congress of the ESCRS
Reference: PO775 | Type: Poster | DOI: 10.82333/nwa6-r767
Authors: Doo Roo Kim* 1 , Yoo Jung Kim 2 , Min Ho Kang 3
1Department of Ophthalmology,Hanyang University Guri Hospital,Guri,Korea, Republic Of, 2Department of Ophthalmology,Hanyang University College of Medicine,Seoul,Korea, Republic Of;Department of Ophthalmology,Hanyang University Hospital,Seoul,Korea, Republic Of, 3Department of Ophthalmology,Hanyang University College of Medicine,Seoul,Korea, Republic Of;Department of Ophthalmology,Hanyang University Guri Hospital,Guri,Korea, Republic Of
Purpose
The aim of this study is to investigate the repeatability of corneal topography measurements using the Galilei anterior segment camera in patients with keratoconus, according to the topographic position across the cornea.
Setting
The retrospective study was conducted on patients diagnosed with keratoconus who visited the ophthalmology department from January 2021 to July 2021. Patients with a grade 2 or higher severity of dry eye according to the DEWS II classification were excluded
Methods
All patients were measured for anterior and posterior axial curvature, and corneal thickness using the Galilei anterior segment camera. These measurements were performed consecutively three times, and each parameter was obtained from 18,002 points across the entire cornea. The mean of the absolute differences between the three measurements was defined as the variation, and this was visualized using a color map. The ratio of unacceptable variation was defined as the percentage of values over 0.5D in corneal refractive power and over 25um in corneal thickness and was assessed for anterior axial curvature, posterior axial curvature, and corneal thickness.
Results
The ratio of unacceptable variation for anterior axial curvature, posterior axial curvature, and corneal thickness in patients with keratoconus was 37.5%, 6.64%, 12.09% respectively, and in normal individuals, it was 7.1%, 1.0%, and 2.1%, respectively (p<0.001 for all). The largest variability was observed in anterior axial curvature, particularly around the cone. When considering the stage of keratoconus, there was no significant difference in variability for anterior axial curvature, posterior axial curvature, and corneal thickness between Stage 1 and Stage 2.
Conclusions
Patients with keratoconus showed lower concordance in refractive values and corneal thickness measurements at various corneal locations when measured three times with the Galilei anterior segment analyzer, compared to normals. Careful consideration is needed when examining anterior axial curvature to determine the progression of keratoconus, and assessing posterior axial curvature and corneal thickness may be necessary for determining its progression.