Best waveform score for diagnosing keratoconus

Luz, Allan; Fontes, Bruno Machado; Lopes, Bernardo; Ramos, Isaac; Faria-Correia, Fernando; Schor, Paulo; Ambrósio, Renato

doi:10.1590/s0034-72802013000600002

Cited by 5 publications

(3 citation statements)

References 23 publications

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“…Ademais, também realizaram a análise das propriedades biomecânicas da córnea pelo método analisador de resposta ocular (ORA) 2 . Já Luz et al determinaram que as melhores medidas do escore da forma de onda (WS) foram superiores à média das medidas consecutivas da ORA para o diagnóstico de ceratocone 11 .…”

Section: Resultsunclassified

Ceratocone: uma revisão quanto ao diagnóstico e tratamento

Oliveira

Mota

2022

R. Saúde

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Ceratocone é uma doença que afeta a córnea, essa é um tecido do olho humano que apura a qualidade da imagem produzida na retina. Constitui-se de uma membrana convexa, translúcida, inervada, sensível, sendo o único tecido avascular do corpo humano que se situa na parte anterior do globo ocular. Foi realizada uma revisão sistemática da literatura, com base em 20 artigos escolhidos por sua importância, relevância e dados levantados, variando entre os anos de 1945 e 2019, com o uso dos bancos de dados Scielo, Pubmed e Lilacs. Bem como o uso da tomografia da córnea e do segmento anterior, estudada por Bruno de Freitas Valbon, et al. , parece ser um método eficaz para aumentar a sensibilidade e a especificidade do diagnóstico e detecção precoce da ectasia corneana do tipo ceratocone. Como também, Bernardo Teixeira Lopes, et al. , estudou o perfil de espessura horizontal detectando o ceratocone, com capacidade comparável aos índices mais complexos. O diagnóstico do ceratocone abrange uma cuidadosa análise da córnea, abrangendo mecanismos simples aos mais complexos. Já o tratamento, destaca-se o crosslinking como método terapêutico efetivo, até o transplante de córnea nos últimos casos.

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Section: Resultsunclassified

Ceratocone: uma revisão quanto ao diagnóstico e tratamento

Oliveira

Mota

2022

R. Saúde

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“…Hence, analyzing biomechanical properties of normal and subclinical KC eyes has gained special relevance. [25][26][27][28] Biomechanical characterization is still challenging because of several biasing factors, such as the intraocular pressure and corneal thickness. While other noncontact tonometer, the Reichert ORA (Buffalo, NY, USA) monitors corneal applanation response through the reflex of an infrared beam with diagnostic capability to detect ectasia, [29][30][31] ultra-high-speed Scheimpflug camera provides a dynamic visualization of the corneal deformation process with detailed information of the deformation response obtained during the NCT.…”

Section: Discussionmentioning

confidence: 99%

Corneal Deformation Response with Dynamic Ultra-high-speed Scheimpflug Imaging for Detecting Ectatic Corneas

Ramos¹,

Salomão²,

Correia³

2016

International Journal of Keratoconus and Ectatic Corneal Diseases

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Purpose:To test the ability of metrics derived from corneal response to noncontact tonometry (NCT) to distinguish between normal and ectatic cases. Materials and methods:The prototype of CorVis ST (Oculus, Wetzlar, Germany) was used for assessing corneal biomechanical response using ultra-high-speed 8 mm horizontal Scheimpflug photography, taking 4,330 frames per second during NCT. Patients were stratified based on clinical data, including rotating Scheimpflug corneal tomography (Oculus Pentacam HR). Biomechanical data from one eye randomly selected of 177 patients with normal corneas (N) and from 79 patients with bilateral keratoconus (KC) were investigated. Group forme fruste keratoconus (FFKC) was composed of 20 eyes with normal topographic patterns from cases with ectasia detected in the fellow eye. Group keratoconus suspect (KCS) had 16 eyes from 16 patients with topographic patterns suspicious of KC but documented stability over 3 years and normal tomographic findings. A combination of deformation parameters using linear regression analysis (Prototype Factor 1, pF1) was created by the BrAIn (Brazilian Artificial Intelligence on Corneal Tomography and Biomechanics) study group in order to provide the best possible separation of KC and normals.Results: Statistical significant differences were found for N × KC for several parameters, including first and second applanation times, deformation amplitude, and maximal concavity radius (Mann-Whitney, p < 0.001). However, the areas under the receiver operating characteristic curves (AUC) were lower than 0.90. The pF1 had AUC of 0.945 (IC 0.909-0.97; sensitivity = 87.3% and specificity = 89.3%). The pF1 had statistically significant differences between the ectatic (KC and FFKC) and nonectatic groups (N and KCS) (p < 0.05, Kruskall-Wallis Test with post hoc Dunn's test). Conclusion:Corneal deformation response analysis by ultrahigh-speed 8 mm horizontal Scheimpflug photography provides relevant data for distinguishing ectatic and nonectatic corneas but cannot be used independently to detect KC. This data may be integrated with corneal tomography data for enhancing sensitivity and specificity for screening ectasia.

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“…11 We used the examination with the best waveform score (ie, the best quality measurement) after four consecutive measurements. All ORA and Pentacam data were obtained by the same experienced operator (BV) in a consistent way during office hours.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Combined Tomography and Biomechanics Data for Distinguishing Forme Fruste Keratoconus

Luz¹,

Lopes

Hallahan

et al. 2016

J Refract Surg

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PURPOSE To evaluate the performance of the Ocular Response Analyzer (ORA) (Reichert Ophthalmic Instruments, Depew, NY) variables and Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) tomographic parameters in differentiating forme fruste keratoconus (FFKC) from normal corneas, and to assess a combined biomechanical and tomographic parameter to improve outcomes. METHODS Seventy-six eyes of 76 normal patients and 21 eyes of 21 patients with FFKC were included in the study. Fifteen variables were derived from exported ORA signals to characterize putative indicators of biomechanical behavior and 37 ORA waveform parameters were tested. Sixteen tomographic parameters from Pentacam HR were tested. Logistic regression was used to produce a combined biomechanical and tomography linear model. Differences between groups were assessed by the Mann–Whitney U test. The area under the receiver operating characteristics curve (AUROC) was used to compare diagnostic performance. RESULTS No statistically significant differences were found in age, thinnest point, central corneal thickness, and maximum keratometry between groups. Twenty-one parameters showed significant differences between the FFKC and control groups. Among the ORA waveform measurements, the best parameters were those related to the area under the first peak, p1area1 (AUROC, 0.717 ± 0.065). Among the investigator ORA variables, a measure incorporating the pressure-deformation relationship of the entire response cycle was the best predictor (hysteresis loop area, AUROC, 0.688 ± 0.068). Among tomographic parameters, Belin/Ambrósio display showed the highest predictive value (AUROC, 0.91 ± 0.057). A combination of parameters showed the best result (AUROC, 0.953 ± 0.024) outperforming individual parameters. CONCLUSIONS Tomographic and biomechanical parameters demonstrated the ability to differentiate FFKC from normal eyes. A combination of both types of information further improved predictive value.

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Best waveform score for diagnosing keratoconus

Cited by 5 publications

References 23 publications

Ceratocone: uma revisão quanto ao diagnóstico e tratamento

Ceratocone: uma revisão quanto ao diagnóstico e tratamento

Corneal Deformation Response with Dynamic Ultra-high-speed Scheimpflug Imaging for Detecting Ectatic Corneas

Enhanced Combined Tomography and Biomechanics Data for Distinguishing Forme Fruste Keratoconus

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