Reproducibility and Repeatability of Central Corneal Thickness Measurement in Keratoconus Using the Rotating Scheimpflug Camera and Ultrasound Pachymetry

Sanctis, Ugo de; Missolungi, Alessandro; Mutani, Bernardo; Richiardi, Lorenzo; Grignolo, Fm

doi:10.1016/j.ajo.2007.07.021

Cited by 143 publications

(109 citation statements)

References 30 publications

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“…Logistic regression was used to support the cutoff point identified with the ROC curve analysis. (5)(6)(7)(8)(9)(10)(11)(12)(13)(14) . However, accurate differentiation of keratoconus from healthy corneas is not yet sufficient, as there is a need to detect corneas with a higher susceptibility to becoming ectatic after laser photoablative surgery (15)(16) .…”

Section: Ability Of Corneal Biomechanical Metrics and Anterior Segmenmentioning

confidence: 99%

Ability of corneal biomechanical metrics and anterior segment data in the differentiation of keratoconus and healthy corneas

Fontes¹,

Ambrósio²,

Jardim³

et al. 2010

Arq. Bras. Oftalmol.

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Purpose: To evaluate the sensitivity, specificity, and test accuracy of corneal biomechanical metrics and anterior segment data in differentiating keratoconus from healthy corneas. Methods: Comparative case series. Patients with and without keratoconus (gender and age-matched) were submitted for complete eye examinations including corneal hysteresis (CH) and corneal resistance factor (CRF) as measured by the Ocular Response Analyzer and anterior segment data as gathered through Pentacam assessments. The anterior segment data measurement included average central keratometric readings (K-Ave), corneal astigmatism (CA), central corneal thickness (CCT), anterior chamber depth (AC depth) and corneal volume (CV). All parameters were assessed, compared and analyzed. A receiver operating characteristic (ROC) curve was used to identify the best cutoff point by which to maximize the sensitivity and specificity of discriminating keratoconus from normal corneas for each data category. Results: Seventy seven eyes from forty three patients (24 male, 19 female) with keratoconus and eighty six eyes from forty three (24 male, 19 female) healthy controls were enrolled. ROC curve analysis showed poor overall predictive accuracy for all studied parameters in differentiating keratoconus from normal corneas. The highest sensitivity (79.2%) was obtained for both AC depth and CH (cutoff points 3.22 mm and 9.39 mmHg respectively). The best specificity (89.5%) and test accuracy (80.34%) were obtained for CA (cutoff point of 2.2 D). Conclusion: When considered together, studied parameters showed statistical differences between groups. However, when considered independently they presented low sensitivity, specificity and test accuracy in differentiating keratoconus from healthy corneas. Keywords: Cornea; Corneal diseases; Corneal topography; Biomechanics; Keratoconus. RESUMOObjetivo: Avaliar a sensibilidade, especificidade e acurácia de parâmetros biomecânicos e anatômicos do segmento anterior isolados na diferenciação de córneas saudáveis e com ceratocone. Métodos: Estudo tipo série de casos comparativa. Pacientes com ceratocone e controles saudáveis foram pareados (idade e sexo) e submetidos a exame oftalmológico completo, incluindo avaliação biomecânica (ORA) e tomográfica (Pentacam). Ceratometria central média, astigmatismo corneano, espessura corneana central, profundidade da câmara anterior, volume corneano, CH e CRF foram estabelecidos, avaliados e comparados. Curvas ROC (Receiver operating characteristic) foram utilizadas para identificar o melhor valor de corte que apresentasse a maior sensibilidade e especificidade na discriminação entre ceratocone e córneas saudáveis para cada dado estudado. Resultados: Setenta e sete olhos de 43 pacientes com ceratocone (24 homens e 19 mulheres) e 86 olhos de pacientes saudáveis (24 homens e 19 mulheres) foram incluídos no estudo. Curvas ROC mostraram baixa acurácia na predição do diagnóstico de ceratocone em todos os parâmetros isolados estudados. Maior sensibilidade encontrada foi 79,...

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Section: Ability Of Corneal Biomechanical Metrics and Anterior Segmenmentioning

confidence: 99%

Ability of corneal biomechanical metrics and anterior segment data in the differentiation of keratoconus and healthy corneas

Fontes¹,

Ambrósio²,

Jardim³

et al. 2010

Arq. Bras. Oftalmol.

View full text Add to dashboard Cite

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“…[12][13][14] In this study, corneal topography (Allegro Oculyzer, WaveLight AG, Erlangen, Germany) was conducted with undilated pupils under scotopic conditions by a single experienced technician. Scans were taken in automatic mode with proper quality.…”

Section: Examinationsmentioning

confidence: 99%

“…Maximum keratometry and corneal pachymetry at the thinnest location were recorded at baseline and 1 year after CXL treatment. 13,14 Cone location was determined according to the topographic coordinates of maximum keratometry as follows: central cone (maximum K within the central 3 mm optical zone), paracentral cone (3-5 mm optical zone), and peripheral cone (outside the central 5 mm optical zone).…”

Section: Examinationsmentioning

confidence: 99%

Factors affecting outcomes of corneal collagen crosslinking treatment

Toprak

Yaylalı

Yıldırım

2013

Eye

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Purpose To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus. Methods This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (o30 andZ30 years), gender, preoperative corrected distance visual acuity (CDVA, o0.3 and Z0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, o54 and Z54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (o450 and Z450 mm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment. Results In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (Po0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (Z0.3 logMAR) experienced more visual improvement after CXL treatment (Po0.001). However, an age Z30 years and a baseline thinnest pachymetry less than 450 mm were found significantly associated with more flattening in maximum keratometry (P ¼ 0.024, P ¼ 0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P40.05). Conclusions In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.

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“…However, UP is a manual technique, and thus, the interexaminer reproducibility of this instrument, although suitable, is slightly lower [8,10]. It also has the disadvantage that the measurements depend on the contact between the cornea and the probe, which may change according to the pressure applied by the operator and can lead to ocular surface distortion [2].…”

Section: Discussionmentioning

confidence: 99%

Agreement between Central Corneal Thickness Measured Using Pentacam, Ultrasound Pachymetry, Specular Microscopy and Optic Biometer Lenstar LS 900 and the Influence of Intraocular Pressure

Borrego-Sanz

Sáenz-Francés²,

Bermúdez-Vallecilla³

et al. 2014

Ophthalmologica

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Purpose: To compare central corneal thickness (CCT) values obtained by Lenstar (LE), Pentacam (PC), specular microscopy (SM) and ultrasound pachymetry (UP) in healthy corneas and study their influence on intraocular pressure (IOP) readings determined by Goldmann applanation tonometry (GAT). Methods: CCT was measured in 76 healthy subjects by LE, PC, SM and UP. We established Lin's concordance correlation coefficient (ρ-C) between different techniques. The influence of CCT on GAT was established through univariate linear regression models, IOP being the dependent variable. Results: The highest ρ-C was found between LE and SM at 0.94 (95% CI: 0.91-0.96) and between LE and UP at 0.95 (95% CI: 0.94-0.97). IOP readings showed less variability when CCT was determined using LE (7.7%, B = 0.16; 95% CI: 0.004-0.28). Conclusions: Although CCT values obtained with UP, PC, SM and LE show good correlation, these methods are not completely interchangeable. The amount of IOP variation differs when CCT is determined using LE or SM.

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Reproducibility and Repeatability of Central Corneal Thickness Measurement in Keratoconus Using the Rotating Scheimpflug Camera and Ultrasound Pachymetry

Cited by 143 publications

References 30 publications

Ability of corneal biomechanical metrics and anterior segment data in the differentiation of keratoconus and healthy corneas

Ability of corneal biomechanical metrics and anterior segment data in the differentiation of keratoconus and healthy corneas

Factors affecting outcomes of corneal collagen crosslinking treatment

Agreement between Central Corneal Thickness Measured Using Pentacam, Ultrasound Pachymetry, Specular Microscopy and Optic Biometer Lenstar LS 900 and the Influence of Intraocular Pressure

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