A review of imaging modalities for detecting early keratoconus

Zhang, Xuemin; Munir, Saleha Z.; Karim, Syed Aftab; Munir, Wuqaas M.

doi:10.1038/s41433-020-1039-1

Cited by 37 publications

(32 citation statements)

References 94 publications

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“…Although identifying clinical symptoms and slit-lamp findings in keratoconus are important, corneal topography is currently the primary diagnostic tool for keratoconus detection [2]. In incipient cases, however, the use of a single parameter as a diagnostic factor is not sufficiently accurate, and pachymetry and corneal aberration data are now also commonly used in conjunction with corneal topography to aid early diagnosis and monitor progression and treatment outcomes [2,152]. In addition to corneal topography that provides two-dimensional imagining of the corneal surface based on curvature data, corneal tomography is a three-dimensional imaging technique that characterises the anterior/posterior corneal surfaces based on curvature data of the anterior surface and elevation data of both the anterior and posterior corneal surfaces, along with corneal thickness distribution [153], which have found critical to enhance the sensitivity and specificity for detecting corneal ectasia in comparison to corneal topography [133,154].…”

Section: Clinical Featuresmentioning

confidence: 99%

Keratoconus: An updated review

Santodomingo-Rubido

Carracedo

Suzaki

et al. 2022

Contact Lens and Anterior Eye

328

204

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Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20-to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal crosslinking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.

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Section: Clinical Featuresmentioning

confidence: 99%

Keratoconus: An updated review

Santodomingo-Rubido

Carracedo

Suzaki

et al. 2022

Contact Lens and Anterior Eye

328

204

View full text Add to dashboard Cite

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“… 2–4 Diagnosing moderate or advanced KC using clinical findings coupled with topographic, topometric, tomographic, and biomechanical indices is straight forward. 5 , 6 The challenge remains in detecting the disease in its earliest subclinical stage. Early detection of KC has gained importance to allow for corneal crosslinking, a procedure that delays or halts progression of disease.…”

Section: Introductionmentioning

confidence: 99%

Keratoconus Features on Corneal Higher-Order Aberration Ablation Maps: Proof-of-Concept of a New Diagnostic Modality

Wallerstein

Racine

Salimi

et al. 2021

OPTH

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Purpose To assess the potential application of corneal higher-order aberration (HOA) excimer ablation map imaging in identifying reproducible keratoconus (KC) features and to explore if newly derived map metrics correlate to Pentacam KC indices. Methods Case series of 12 eyes with KC ≥ grade 2. Topolyzer Vario corneal imaging with its resultant HOA ablation map islands were analyzed for their centroid, distance from center, angular position, orientation, sphericity, diameter, area, and maximal ablation depth. Correlations to Pentacam indices were studied. Results All eyes showed recurrent features with an arrangement of two elliptical paracentral ablation islands, one deep inferotemporal and one shallow superonasal, in direct mirror-like opposition to each other. These were always accompanied by superior peripheral ablation crescents. The two paracentral islands had highly reproducible distance from center (1.2 ± 0.1 mm and 1.3 ± 0. 2 mm) and angular positions (246.8 ± 15.9° and 76.7 ± 7.7°), with greater variation in ablation depth (68.3 ± 33.2 µm and 17.6 ± 12.1 µm). Distance from center of the peripheral superior crescents was highly reproducible (3.3 ± 0.1 mm), with a larger range of depth (74.5 ± 37.2 µm). The deep paracentral inferotemporal island “hot spot” was coincident with the topographical apical cone. Strong correlations were found between the depth of the inferotemporal island and Pentacam indices of posterior radius curvature (PRC: R = −0.74) and Belin/Ambrosio enhanced ectasia total deviation (BAD-D: R = 0.71). Conclusion The corneal HOA ablation map revealed a recurring, distinct, easily recognizable pattern in KC eyes. There was a strong correlation between the depth of novel HOA ablation map metrics and validated Pentacam KC indices. Novel information can be extracted from the corneal HOA ablation map giving it the potential to be a new modality to diagnose and grade KC.

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“…As the absolute contraindication of keratorefractive surgery, its exact preoperative diagnosis is especially important. Despite the fact that the clinical diagnosis of moderate and advanced keratoconus is not difficult, the diagnosis of early keratoconus still remains a challenge [ 18 ]. Early keratoconus is considered as one of the most important independent risk factors for iatrogenic keratoectasis.…”

Section: Discussionmentioning

confidence: 99%

Comparative analysis of the morphological and biomechanical properties of normal cornea and keratoconus at different stages

Guo

Tian

et al. 2021

Int Ophthalmol

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Purpose To compare the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Methods A total of 408 patients (517 eyes) with keratoconus were included in this study. According to the Topographic Keratoconus (TKC) grading method, keratoconus was divided into stage I (TKC = 1, 130 eyes), stage II (TKC = 1–2, 2, 164 eyes), stage III (TKC = 2–3, 3, 125 eyes) and stage IV (TKC = 3–4, 4, 98 eyes). A total of 158 normal subjects (158 eyes) were recruited as the normal group. The corneal morphological parameters and biomechanical parameters were obtained with Scheimpflug tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST), and the receiver operating characteristic (ROC) curves were drawn. Results Each corneal morphological and most biomechanical parameters of the keratoconic eyes were significantly different from those of the normal eyes in this study (p < 0.001). ROC curve demonstrated that most parameters in this study showed high efficiency in diagnosing keratoconus (the area under the ROC (AUC) was > 0.9), with the Belin-Ambrósio deviation (BAD-D) and Tomographic and Biomechanical Index (TBI) showing higher efficiency. The efficiency of BAD-D and TBI was high in differentiating keratoconus at different stages (AUC > 0.963). The comparison of ROC curves of keratoconus at different stages did not reveal statistically significant differences for TBI. Conclusion BAD-D and TBI can effectively diagnose stage I keratoconus. Moreover, the efficiency of TBI is the same in diagnosing keratoconus at all stages, while the diagnostic efficiency of other parameters increases with the increase in keratoconus stages.

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A review of imaging modalities for detecting early keratoconus

Cited by 37 publications

References 94 publications

Keratoconus: An updated review

Keratoconus: An updated review

Keratoconus Features on Corneal Higher-Order Aberration Ablation Maps: Proof-of-Concept of a New Diagnostic Modality

Comparative analysis of the morphological and biomechanical properties of normal cornea and keratoconus at different stages

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