Long-Term Changes Of Corneal Power In Borderline Young Cases With Suspected But Excluded Keratoconus
Published 2023 - 41st Congress of the ESCRS
Reference: PO0727 | Type: Free paper | DOI: 10.82333/0tw0-6y88
Authors: Aki Tanimura* 1 , Shizuka Koh 2 , Ryota Inoue 3 , Sanae Asonuma 1 , Naoyuki Maeda 1 , Kohji Nishida 1
1Ophthalmology,Osaka University Graduate School of Medicine,Osaka,Japan, 2Innovative Visual Science,Osaka University Graduate School of Medicine,Osaka,Japan;Ophthalmology,Osaka University Graduate School of Medicine,Osaka,Japan, 3Innovative Visual Science,Osaka University Graduate School of Medicine,Osaka,Japan;SEED,Tokyo,Japan
Purpose
It has been clinically experienced that keratoconus (KC) may be suspected in young patients for the following reasons such as significant astigmatism, large inter-eye refractive asymmetry, or a family history, even if there is no abnormality on slit-lamp microscopy. The aim of this study is to retrospectively investigate long-term changes of corneal power by Fourier analysis using anterior segment optical coherence tomography (OCT), in young patients referred to a university hospital for close examination with suspicion that KC may be present.
Setting
Osaka University Hospital, Osaka, Japan
Methods
Thirty-six eyes of 18 patients were enrolled. Inclusion criteria were patients 1) suspected for KC without clinical and topographic signs bilaterally and 2) younger than 25 years old at the initial visit. Based on amount of astigmatism at the initial visit, eyes were divided into Low-As (less than 2.0D) and High-As (2.0D and above) groups. Fourier analysis using OCT decomposed dioptric data from both anterior and posterior corneal surfaces into spherical, regular astigmatism, asymmetry, and higher-order irregularity components in the central 6mm zone. Longitudinal changes in Fourier parameters between the initial and the last visit were investigated using linear mixed-effects models in 2 groups.
Results
Enrolled eyes were divided into 13 eyes as Low-As group (mean age:15.3±2.9 years) and 23 eyes as High-As group (mean age:15.8±2.7 years). Significant increase both in the anterior regular astigmatism and the posterior regular astigmatism were observed in Low-As group (P <0.01, respectively), while significant increase were observed only in the posterior regular astigmatism in High-As group (P <0.01). No significant changes during the observation period were found in other Fourier parameters in both groups.
Conclusions
Based on the quantitative Fourier analysis of long-term corneal power with OCT, increase in anterior/posterior regular astigmatism were observed in young cases with low astigmatism without bilateral clinical/topographic KC signs, when quantitative refractive data were borderline for suspicious KC or having a KC familial history. Future studies with a longer follow-up period are required.