Prediction of anterior ocular surface sagittal heights using Placido-based corneal topography in healthy eyes.
Ophthalmic Physiol Opt
; 42(5): 1023-1031, 2022 09.
Article
em En
| MEDLINE
| ID: mdl-35703419
ABSTRACT
PURPOSE:
To investigate the validity of Placido-based corneal topography parameters to predict corneoscleral sagittal heights measured by Fourier-based profilometry at various diameters.METHODS:
Minimal (Minsag ), maximal (Maxsag ) sagittal height, toricity (Maxsag - Minsag ) and axis of the flattest meridian (Minsag ) of 36 subjects (mean age 25.4 SD ± 3.2 years; 21 female) were measured using the Eye Surface Profiler and analysed for diameters (chord length) of 8 to 16 mm (in 2-mm intervals). Furthermore, corneal central radii, corneal astigmatism, eccentricity and diameter were measured using the Keratograph 5 M.RESULTS:
Using multiple linear regression analysis, the best equation for predicting the sagittal heights for 8 mm (r2 = 0.95), and 10 mm (r2 = 0.93) diameters included corneal central radii and eccentricity. The best equation for predicting sagittal heights for 12 mm (r2 = 0.86), 14 mm (r2 = 0.78) and 16 mm (r2 = 0.65) diameters included corneal central radii, eccentricity and corneal diameter. Corneal astigmatism was significantly correlated with sagittal height toricity for 8 and 10 mm diameters (r2 = 0.50 and 0.29; p < 0.01), while no correlation was observed for 12, 14 and 16 mm diameters (p = 0.18 to p = 0.76). The axis of the flattest corneal meridian measured by Placido-based topography was significantly correlated with the axis of the flattest meridian measured by Fourier-based profilometry for 8, 10 and 12 mm diameters (r2 = 0.17 to 0.44; p < 0.05), while there was no correlation for 14 and 16 mm diameters (p = 0.48 and p = 0.75). For a typical soft contact lens diameter of 14 mm, 78% of the variance could be determined with a corneal topographer and 68% with keratometry and corneal diameter measurement.CONCLUSIONS:
The combination of corneal central radii, eccentricity and corneal diameter measured by Placido-based topography is a valid predictor of the corneoscleral sagittal height in healthy eyes. Scleral toricity and axis of the flattest meridian seem to be independent from Placido-based corneal parameters and requires additional measuring tools.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Astigmatismo
/
Lentes de Contato Hidrofílicas
/
Doenças da Córnea
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Adult
/
Female
/
Humans
Idioma:
En
Revista:
Ophthalmic Physiol Opt
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Alemanha