Relationship of placido corneal topography data with scleral lens fitting parameters.
Cont Lens Anterior Eye
; 42(1): 20-27, 2019 02.
Article
em En
| MEDLINE
| ID: mdl-30055934
ABSTRACT
PURPOSE:
To analyze the relationship between corneal sagittal height and asymmetry parameters derived from Placido-videokeratoscopy with the parameters of fitted scleral lenses (ScCLs).METHODS:
Corneal topographies were measured with MedmontE300 in a total of 126 eyes with irregular and regular corneas before ScCL fitting were analyzed. Measurements of sagittal height (OC-SAG) at steep and flat corneal meridians were obtained for 10 mm and 12 mm chords. Estimated Height (EHChord) parameters were taken for a chord equal to the diameter of the lens that each subject was wearing at different semi-meridians. Corneal asymmetry (difference in OC-SAG between steep and flat corneal meridians) was also assessed. These outcomes were correlated to ScCL parameters that subjects were wearing after 1 month.RESULTS:
The mean ScCL-SAG was 4696 ± 240 µm, and the mean OC-SAG ranged from 1891 µm (10 mm), 2914 µm (12 mm), and between 4162 µm and 4251 µm for EH0-180º and EH30-210º. Stronger correlations (p < 0.001) between OC-SAG and ScCL-SAG were determined for EH0-180º (r = 0.595) and EH30-210º (r = 0.618). The mean differences between OC-SAG and ScCL-SAG were between 447 ± 290 µm (EH0-180º) and 389 ± 360 µm (EH30-210º). There was no relationship between corneal asymmetry and the need to fit a ScCL with toric haptic design in irregular corneas. Orientation of flat corneal and scleral meridians were similar only in corneas with high regular astigmatism.CONCLUSIONS:
EHChord attributes were the parameters that best correlated with the ScCL-SAG. The corneal asymmetry was shown to be a poor predictor for the need to fit a ScCL with toricity at landing zone in irregular corneas, but could have some predictive power in regular corneas.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Erros de Refração
/
Esclera
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Ajuste de Prótese
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Lentes de Contato Hidrofílicas
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Topografia da Córnea
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Ceratocone
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article