Interobserver and intraobserver reliability of a classification scheme for corneal topographic patterns

Rasheed, Karim; Rabinowitz, Yaron S.; Remba, Diana; Remba, Melvin J.

doi:10.1136/bjo.82.12.1401

Cited by 15 publications

(9 citation statements)

References 8 publications

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“…24,25 Axial maps were classified into 1 of 10 subgroups: round, oval, superior steepening, inferior steepening, and irregular symmetrical, symmetrical with skewed axis, asymmetric with inferior steepening, asymmetric with superior steepening, and asymmetric with skewed axis.…”

Section: Methodsmentioning

confidence: 99%

Computerized corneal tomography and associated features in a large New Zealand keratoconic population

Jordan

Zamri

Wheeldon

et al. 2011

Journal of Cataract and Refractive Surgery

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Section: Methodsmentioning

confidence: 99%

Computerized corneal tomography and associated features in a large New Zealand keratoconic population

Jordan

Zamri

Wheeldon

et al. 2011

Journal of Cataract and Refractive Surgery

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“…This classification scheme has been reported in detail. 10,11 The other 10% of videokeratographs were assigned according to a pattern agreed to by at least 2 of the 3 observers. The categories were as follows: round, oval, irregular, inferior steepening (IS), superior steepening (SS), symmetric bow tie (SB), AB with SS, AB with IS, SB with SRAX, and AB/SRAX.…”

Section: Methodsmentioning

confidence: 99%

“…The categories were as follows: round, oval, irregular, inferior steepening (IS), superior steepening (SS), symmetric bow tie (SB), AB with SS, AB with IS, SB with SRAX, and AB/SRAX. 11,12 Because of the moderate sample size, the 10 patterns were placed into 1 of 3 groups as follows: Group 1, symmetric patterns including round, oval, and SB; Group 2, all asymmetric patterns except AB/SRAX; Group 3, only the AB/SRAX pattern (extremely rare in normal eyes 11,12 ).…”

Section: Methodsmentioning

confidence: 99%

Keratoconus: Classification scheme based on videokeratography and clinical signs

Yang

Rabinowitz

2009

Journal of Cataract and Refractive Surgery

135

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PURPOSE To determine in a longitudinal study whether there is correlation between videokeratography and clinical signs of keratoconus that might be useful to practicing clinicians. SETTING Cornea-Genetic Eye Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA. METHODS Eyes grouped as keratoconus, early keratoconus, keratoconus suspect, or normal based on clinical signs and videokeratography were examined at baseline and followed for 1 to 8 years. Differences in quantitative videokeratography indices and the progression rate were evaluated. The quantitative indices were central keratometry (K), the inferior–superior (I–S) value, and the keratoconus percentage index (KISA). Discriminant analysis was used to estimate the classification rate using the indices. RESULTS There were significant differences at baseline between the normal, keratoconus-suspect, and early keratoconus groups in all indices; the respective means were central K: 44.17 D, 45.13 D, and 45.97 D; I–S: 0.57, 1.20, and 4.44; log(KISA): 2.49, 2.94, and 5.71 (all P<.001 after adjusting for covariates). Over a median follow-up of 4.1 years, approximately 28% in the keratoconus-suspect group progressed to early keratoconus or keratoconus and 75% in the early keratoconus group progressed to keratoconus. Using all 3 indices and age, 86.9% in the normal group, 75.3% in the early keratoconus group, and 44.6% in the keratoconus-suspect group could be classified, yielding a total classification rate of 68.9%. CONCLUSIONS Cross-sectional and longitudinal data showed significant differences between groups in the 3 indices. Use of this classification scheme might form a basis for detecting subclinical keratoconus.

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“…Both patients (II-4, III-14) had an AB/SRAX pattern that has been demonstrated in several studies to be an excellent and highly accurate videokeratograph recognition pattern for keratoconus. 7,26,28 The significant linkage evidence (LOD ϭ 3.53) and the fact that all affected individuals in this pedigree inherited the identical haplotype within each of the two families argue that there is likely to be a novel locus on 5q14.3-q21.1, which may be specific to this pedigree or a subset of familial dominant keratoconus. Considering all previously reported and this current linkage evidence in aggregate, it is clear that we are dealing with a genetically heterogeneous disorder although some of these loci may be the result of the type 1 error.…”

Section: Discussionmentioning

confidence: 99%

“…This classification scheme has previously been demonstrated to be highly reliable and reproducible even among untrained observers. 28 Agreement was necessary among the three observers to assign a videokeratograph a specific pattern. Videokeratographs were assigned as either having an AB/SRAX pattern (thus as affected) or one of the other patterns that form part of this classification scheme (designated as normal) 25 (Table 1).…”

Section: Study Subjects and Clinical Evaluationmentioning

confidence: 99%

Genomewide linkage scan in a multigeneration Caucasian pedigree identifies a novel locus for keratoconus on chromosome 5q14.3-q21.1

Tang

Rabinowitz

Taylor

et al. 2005

Genetics in Medicine

108

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Purpose: Keratoconus is a corneal dystrophy with an incidence of 1 in 2000 and a leading cause for cornea transplantation in Western developed countries. Both clinical observations and segregation analyses suggest a major role for genes in its pathogenesis. It is genetically heterogenous, most commonly sporadic, but inherited patterns with recessive or dominant modes have also been reported. We studied a four-generation autosomaldominant pedigree to identify disease loci for keratoconus. Methods: A two-stage genome-wide scan was applied to 27 family members. First linkage analysis was performed with 343 microsatellite markers along the 22 autosomal chromosomes at Ϸ10 cM density. This was followed by fine mapping at Ϸ2 cM density, in regions suggestive of linkage. Multipoint linkage analysis was performed using GeneHunter2. Results: Evidence of suggestive linkage from the initial scan was observed at the 82 to 112 cM region of chromosome 5q14.1-q21.3 with a maximum lod score (LOD) of 3.48 (penetrance ϭ 0.5). Fine mapping by testing an additional 11 microsatellite markers at 1 to 3 cM intervals revealed a narrower and higher peak (99 -119 cM) with LOD 3.53. By analysis of the recombination of haplotypes, the putative locus of keratoconus was further narrowed to a 6 cM region (8.

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Interobserver and intraobserver reliability of a classification scheme for corneal topographic patterns

Abstract: This classification scheme is extremely robust and even in the hands of less experienced observers with minimal training it can be relied upon to provide consistent results.

Cited by 15 publications

References 8 publications

Computerized corneal tomography and associated features in a large New Zealand keratoconic population

Computerized corneal tomography and associated features in a large New Zealand keratoconic population

Keratoconus: Classification scheme based on videokeratography and clinical signs

Genomewide linkage scan in a multigeneration Caucasian pedigree identifies a novel locus for keratoconus on chromosome 5q14.3-q21.1

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