Longitudinal study of the normal eyes in unilateral keratoconus patients

Li, Xiaohui; Rabinowitz, Yaron S.; Rasheed, Karim; Yang, Huiying

doi:10.1016/j.ophtha.2003.06.020

Cited by 290 publications

(204 citation statements)

References 19 publications

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“…Some studies report a higher prevalence in male patients, whereas others indicate that there is no significant difference between genders. 32,38 Race, on the other hand, seems to be an important risk factor as previously indicated. Asians (people from India, Pakistan, and Bangladesh) have prevalence 4.4-7.5 higher than Caucasians.…”

Section: Epidemiologysupporting

confidence: 53%

Keratoconus: an inflammatory disorder?

Galvis

Sherwin

Tello

et al. 2015

Eye

301

199

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Keratoconus has been classically defined as a progressive, non-inflammatory condition, which produces a thinning and steepening of the cornea. Its pathophysiological mechanisms have been investigated for a long time. Both genetic and environmental factors have been associated with the disease. Recent studies have shown a significant role of proteolytic enzymes, cytokines, and free radicals; therefore, although keratoconus does not meet all the classic criteria for an inflammatory disease, the lack of inflammation has been questioned. The majority of studies in the tears of patients with keratoconus have found increased levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and matrix metalloproteinase (MMP)-9. Eye rubbing, a proven risk factor for keratoconus, has been also shown recently to increase the tear levels of MMP-13, IL-6, and TNF-α. In the tear fluid of patients with ocular rosacea, IL-1α and MMP-9 have been reported to be significantly elevated, and cases of inferior corneal thinning, resembling keratoconus, have been reported. We performed a literature review of published biochemical changes in keratoconus that would support that this could be, at least in part, an inflammatory condition.

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Section: Epidemiologysupporting

confidence: 53%

Keratoconus: an inflammatory disorder?

Galvis

Sherwin

Tello

et al. 2015

Eye

301

199

View full text Add to dashboard Cite

show abstract

“…1 On the other hand, diagnosing early keratoconus in patients with normal best spectacle-corrected Currently, Placido disk-based corneal topography is regarded as the most sensitive measurement for detecting ectatic corneal disorders such as keratoconus and pellucid marginal degeneration. 4,31 Topographic analysis reveals characteristic features of these diseases before biomicroscopic signs or symptoms. Normal, suspicious, and abnormal topography patterns of these diseases have been classified.…”

Section: Discussionmentioning

confidence: 99%

“…The identification of very early forms of keratoconus or forme fruste keratoconus, described by Amsler in 1946, 2 is important for evaluating and following patients considered to have asymmetric or unilateral keratoconus 3,4 and for studying family members of patients with the disease. 5 In addition, the preoperative identification of forme fruste keratoconus is crucial in evaluation of candidates for refractive surgery.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9] Placido disk-based corneal topography has been used extensively to diagnose corneal ectasia, and this test has been accepted as the most sensitive method to detect ectatic corneal disorders such as keratoconus and pellucid marginal degeneration. 4,5,10,11 Topographic analysis can point to characteristic clues of these diseases before the development of clinical signs or symptoms. 11,12 Up to date, a lot of indices and differentiation methods, such as the Rabinowitz-McDonnell test, 13 the Klyce-Maeda-Smolek Expert System, 14 KISA% index, 15 and the corneal navigator 16 have been developed to assist ophthalmologist with keratoconus diagnosis.…”

Section: Introductionmentioning

confidence: 99%

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Keratokonus ve Subklinik Keratokonusun Tespit Edilmesi için Pentacamla Korneal Hacim Ölçümleri

Çağıl¹,

Uğurlu²,

Çakmak³

et al. 2013

Tjo

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Sum maryPur po se: To estimate the sensitivity and specificity of corneal volume (CV) measurements in discriminating keratoconus and subclinical keratoconus from normal corneas. Ma te ri al and Met hod: Clinical records and Pentacam measurements of ninety-four patients with keratoconus, 36 patients with subclinical keratoconus, and 166 refractive surgery candidates with normal corneas were evaluated retrospectively. CV within 3, 5, 7, and 10 mm circles around the central cornea was measured in one eye of each patient, using the Pentacam. CV measurements in keratoconus and subclinical keratoconus were compared with normal corneas. Receiver operating characteristic (ROC) curves were used to determine the test's overall predictive accuracy and to identify optimal CV cutoff points to maximize sensitivity and specificity in discriminating keratoconus and subclinical keratoconus from normal corneas. Re sults: Mean CV within a 3.0 mm circle around the central cornea was statistically lower in keratoconus (3.4±0.2 mm 3 , p<0.001) and subclinical keratoconus (3.6±0.2mm 3 , p<0.001) versus normal corneas (3.8±0.3mm 3 ). ROC curve analysis showed high overall predictive accuracy of CV for keratoconus (area under the curve 0.92). Optimal cutoff points were 3.55 mm 3 for keratoconus and 3.65 mm 3 for subclinical keratoconus. These values provided sensitivity and specificity of 83% and 86%, respectively, for keratoconus, and 61% and 74% for subclinical keratoconus. Dis cus si on: CV within a 3.0 mm circle around the central cornea effectively discriminates keratoconus from normal corneas. However, its sensitivity and specificity are lower for subclinical keratoconus diagnosis. (Turk J Ophthalmol 2013; 43: 77-82) Key Words: Corneal volume, keratoconus, pentacam, subclinical keratoconus Özet Amaç: Kornea hacmi (KH) ölçümlerinin keratokonus ve subklinik keratokonusu normal kornealardan ayırt etmedeki duyarlılık ve özgünlüğünün tespit edilmesi. Ge reç ve Yön tem: Doksan dört keratokonus hastası, 36 subklinik keratokonuslu hasta ve 166 refraktif cerrahi adayının klinik kayıtları ve Pentacam ölçümleri retrospektif olarak incelendi. Pentacam kullanarak her hastanın santral kornea etrafındaki 3, 5, 7 ve 10 mm lik dairelerdeki KH'sı ölçüldü. Keratokonus ve subklinik keratokonustaki KH ölçümleri normal kornealarla karşılaştırıldı. Testin tüm tahmini doğruluğunu test etmek ve keratokonus ve subklinik keratokonusu normal kornealardan ayırt etmekte duyarlılık ve özgünlüğü maksimuma çıkaran optimal kesim noktalarının tanımlamak için ROC (Receiver operating characteristic) eğrileri kullanıldı. Sonuçlar: Santral kornea etrafındaki 3,0 mm'lik dairedeki KH; keratokonusta (3,4±0,2mm 3 , p<0,001) ve subklinik keratokonusta (3,6±0,2mm 3 , p<0,001) normal kornealara gore (3,8±0,3 mm 3 ) istatistiksel olarak düşüktü. ROC eğrisi analizi KH'nın keratokonus için yüksek toplam tahmini doğruluğunu gösterdi ( eğri altında kalan alan 0,92). Optimal kesim noktaları keratokonus için 3,55 mm 3 , subklinik keratokonus için ise 3,65 mm 3 idi. Bu değerler, kera...

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“…Keratoconus generally starts at puberty and progresses until the third or fourth decade of life (2) , after which it usually stabilizes. Keratoconus eyes are more elastic and less rigid than normal eyes.…”

mentioning

confidence: 99%

Best waveform score for diagnosing keratoconus

Luz¹,

Fontes²,

Lopes³

et al. 2013

Rev. bras.oftalmol.

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Purpose: To test whether corneal hysteresis (CH) and corneal resistance factor (CRF) can discriminate between keratoconus and normal eyes and to evaluate whether the averages of two consecutive measurements perform differently from the one with the best waveform score (WS) for diagnosing keratoconus. Methods: ORA measurements for one eye per individual were selected randomly from 53 normal patients and from 27 patients with keratoconus. Two groups were considered the average (CH-Avg, CRF-Avg) and best waveform score (CH-WS, CRF-WS) groups. The Mann-Whitney U-test was used to evaluate whether the variables had similar distributions in the Normal and Keratoconus groups. Receiver operating characteristics (ROC) curves were calculated for each parameter to assess the efficacy for diagnosing keratoconus and the same obtained for each variable were compared pairwise using the Hanley-McNeil test. Results: The CH-Avg, CRF-Avg, CH-WS and CRF-WS differed significantly between the normal and keratoconus groups (p<0.001). The areas under the ROC curve (AUROC) for CH-Avg, CRF-Avg, CH-WS, and CRF-WS were 0.824, 0.873, 0.891, and 0.931, respectively. CH-WS and CRF-WS had significantly better AUROCs than CH-Avg and CRF-Avg, respectively (p=0.001 and 0.002). Conclusion: The analysis of the biomechanical properties of the cornea through the ORA method has proved to be an important aid in the diagnosis of keratoconus, regardless of the method used. The best waveform score (WS) measurements were superior to the average of consecutive ORA measurements for diagnosing keratoconus.Keywords: Cornea/physiopathology; Keratoconus/diagnosis; Biomechanics/physiology; Dilatation, pathologic; Diagnostic techniques, ophthalmologic RESUMOObjetivo: Testar se a histerese corneana (CH) e o fator de resistência corneano (CRF) podem discriminar olhos com ceratocone e avaliar se a média de duas medidas consecutivas apresenta desempenho diferente da medida única com a melhor waveform score para diagnósticar o ceratocone. Métodos: Foram realizadas medidas do ORA de um olho por indivíduo, selecionados aleatoriamente a partir de 53 pacientes normais e de 27 pacientes com ceratocone. Dois grupos foram considerados: a média (CH-médio, o CRFmédio) e melhor waveform score (CH-WS, CRF-WS). O teste de Mann-Whitney U-teste foi utilizado para avaliar se as variáveis apresentaram distribuições semelhantes entre os grupos. As curvas (ROC) foram calculadas para cada parâmetro para avaliar eficácia no diagnóstico e as obtidas para cada variável foram comparadas usando o teste de Hanley-McNeil. Resultados: CH-médio, CRF-médio, CH-WS e CRF-WS diferiram significativamente entre os grupos (p<0,001). Já as áreas sob a curva ROC para CHmédio, CRF-médio, CH-WS, e CRF-WS foram 0,824, 0,873, 0,891, 0,931, respectivamente. CH-WS e CRF-WS obtiveram AUROCs significativamente melhores do que CH-médio e CRF-médio (p=0,001 e 0,002). Conclusão: A análise das propriedades biomecânicas da córnea através do ORA demonstrou ser um método auxiliar importante no diagnóstico de cera...

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Longitudinal study of the normal eyes in unilateral keratoconus patients

Cited by 290 publications

References 19 publications

Keratoconus: an inflammatory disorder?

Keratoconus: an inflammatory disorder?

Keratokonus ve Subklinik Keratokonusun Tespit Edilmesi için Pentacamla Korneal Hacim Ölçümleri

Best waveform score for diagnosing keratoconus

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