Fourier Analysis Of Anterior And Posterior Corneal Surfaces Following Anterior Lamellar Keratoplasty
Published 2023 - 41st Congress of the ESCRS
Reference: FP11.03 | Type: Free paper | DOI: 10.82333/087c-nh07
Authors: Keiko Yamada* 1 , Yoshinori Oie 1 , Reiko Kobayashi 1 , Yu Yoshinaga 1 , Takeshi Soma 1 , Shizuka Koh 2 , Satoshi Kawasaki 1 , Naoyuki Maeda 1 , Kohji Nishida 1
1Department of Ophthalmology,Osaka University Graduate School of Medicine,Osaka,Japan, 2Department of Ophthalmology,Osaka University Graduate School of Medicine,Osaka,Japan;Department of Innovative Visual Science,Osaka University Graduate School of Medicine,Osaka,Japan
Purpose
To investigate corneal topography changes using Fourier analysis and its correlation with corrected distance visual acuity (CDVA) after anterior lamellar keratoplasty (ALK).
Setting
Osaka University Hospital, Osaka, Japan
Methods
The medical charts of patients who underwent ALK between 2010 and 2021, with a follow-up period of at least one year, were retrospectively analyzed. A modified stromal hooking technique, a layer-by-layer method, was employed. Corneal dioptric data from the central 3mm zone of the anterior and posterior corneal surfaces was measured at their last visit via anterior segment optical coherence tomography (OCT). Fourier analysis using OCT decomposed dioptric data into spherical, regular astigmatism, asymmetry, and higher-order irregularity (HOI) components. The association between the components and CDVA was analyzed using Spearman’s rank correlation coefficient.
Results
Sixty-three eyes of 56 patients were enrolled. The average CDVA at the last visit was 0.60±0.49 logMAR. A significant association between anterior and posterior surfaces in the three Fourier components, spherical (ρ=0.38, p=0.0023), regular astigmatism (ρ=-0.49, p<0.001), and HOI (ρ=-0.44, p<0.001) were observed. In the anterior surface, there was a significant association between CDVA and three Fourier components, regular astigmatism (ρ=0.39, p=0.0018), asymmetry (ρ=0.38, p=0.0022) and HOI (ρ=0.47, p<0.001). On the other hand, in the posterior surface, a significant association was observed only between CDVA and HOI component (ρ=0.45, p<0.001).
Conclusions
The association between the anterior and posterior corneal surfaces of eyes that underwent ALK was significant in spherical, regular astigmatism, and HOI components, except for asymmetry component. Components of the anterior surface of the cornea by Fourier analysis had greater influence on the postoperative visual acuity, compared to those of the posterior surface of the cornea. This analysis may contribute to better visual function after ALK.