The Influence of Tomographic Corneal Characteristics on Epithelial Thickness Profile

Hashmani, Nauman; Hashmani, Maria; Hashmani, Sharif; Fatima, Kiran; Farid, Neha; Zakaria, Faiza; Qazi, Mujtaba A.

doi:10.7759/cureus.11731

Cited by 3 publications

(4 citation statements)

References 13 publications

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“…Using VHFU technology, Reinstein et al showed that the average central CET was 53.4 ± 4.6 μ m, comparable with SD-OCT [ 22 ]. Using SD-OCT, normal CET profiles were described to be thicker in the central 2 mm of the cornea ranging from 53 to 54 μ m in the center and decreased with a low gradient of −0.43 μ m/mm toward 7 mm midperiphery and a larger gradient of −2.31 μ m/mm toward 9 mm periphery [ 45 , 52 , 60 , 71 – 73 ]; VHF-US studies did not find such thinning trends [ 22 ].…”

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

“…Wang et al also found similar ET profiles in normal and high myopic populations [ 85 ]. CET has also been shown not to be associated with axial length (AL) [ 60 , 83 , 92 ] or refractive errors [ 22 , 45 , 83 , 92 ], regardless of individuals' age or ethnicity. On the other hand, few studies have reported CET to be negatively correlated with AL and myopia; one possible explanation may be the increased friction between the corneal surface and the eyelid nearing each other with longer axial lengths [ 73 , 78 ].…”

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

“…No correlation between CET and keratometry has been found in adults [ 22 , 60 , 74 , 78 ] or children [ 83 ]. Ma and associates found a correlation between the CET and corneal curvature radius among Chinese children in the paracentral and peripheral, but not the central cornea [ 92 ].…”

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

“…Hashmani et al could not find any correlation between different corneal indices, including anterior/posterior surface flat/steep axis, maximum/minimum curvature, corneal astigmatism topography, astigmatism polar values and corneal volume, anterior surface asphericity, and ETM. Posterior surface asphericity was an exception, having a moderate correlation with CET in all areas [ 60 ]. On the other hand, Ozalp and Atalay reported a positive correlation between the anterior corneal curvature radius and CET in myopic populations [ 73 ].…”

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

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Corneal Epithelial Thickness Mapping: A Major Review

Abtahi,

Beheshtnejad,

Latifi

et al. 2024

Journal of Ophthalmology

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The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.

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Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

Section: Corneal Epithelium In Normal Eyesmentioning

confidence: 99%

See 2 more Smart Citations

Corneal Epithelial Thickness Mapping: A Major Review

Abtahi,

Beheshtnejad,

Latifi

et al. 2024

Journal of Ophthalmology

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Repeatability of Corneal Epithelial Thickness Map Using Anterior-Segment Optical Coherence Tomography in Normal and Corneal Disease Patients

Lee,

Han

2024

Korean J Ophthalmol

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Purpose: To evaluate the repeatability of corneal epithelial thickness (CET) measurements in normal eyes and eyes diagnosed with corneal disease using the epithelial thickness map (ETM) of anterior-segment optical coherence tomography (OCT).Methods: In this retrospective study, patients with three OCT scans using the ETM mode of Cirrus OCT between October 2021 and January 2024 were reviewed. Two groups of subjects were included: (1) normal subjects with no history of ophthalmic surgery, corneal diseases, and topical antiglaucoma medication uses; and (2) subjects with corneal diseases including dry eye syndrome, recurrent corneal erosion, pterygium, and others. A total of 57 eyes of 57 normal subjects and 106 eyes of 76 patients with corneal disease were included. ETM was analyzed in 25 zones (one zone within 0–2 mm diameter, eight zones within 2–5 mm diameter, eight zones within 5–7 mm diameter, and eight zones within 7–9 mm diameter). Repeatability was evaluated by calculating intraclass correlation coefficient (ICC), coefficient of variation (CoV), within-subject standard deviation (Sw), and Bland-Altman plot.Results: Among a total of 25 sectors, the normal eyes showed high repeatability (ICC, >0.75; CoV, 2.160%–5.292%; Sw, 0.760– 1.653 μm) in 23 sectors, and corneal diseases patients also showed high repeatability (ICC, >0.75; CoV, 4.167%–9.606%; Sw, 1.298–3.340 μm) in 22 sectors. However, the wide range of 95% limit of agreement width of Bland-Altman plot presented in corneal disease group and some peripheral zones in normal eyes indicates some variability of CET measurements.Conclusions: Except for a few peripheral sectors, ETM of Cirrus OCT provides repeatable CET measurements in normal eyes; however in corneal disease group, repeatability was not consistently high. To measure CET accurately, performing multiple measurements is advised especially in patients with corneal disease and patients in whom peripheral CET values.

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Impact of Corneal Toricity on the Distribution of Corneal Epithelial Thickness

Zhang¹,

Liu²,

Shao³

et al. 2023

J Refract Surg

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Purpose: To investigate the impact of corneal toricity on the distribution characteristics of corneal epithelial thickness (CET). Methods: A total of 330 eyes in 330 healthy participants were included in this study. They were divided into two groups based on the median of the corneal toricity value: low-toricity group (corneal toricity < 1.50 diopters) and high-toricity group (corneal toricity ≥ 1.50 diopters). The CET within a 9-mm–diameter area of the central cornea was obtained using optical coherence tomography. The difference of CET value between flat and steep meridians (F-S CET) was defined to evaluate the CET distribution. The F-S CET between the two groups was compared, and the correlations between F-S CET and the corneal toricity were analyzed. Results: The CET was thinner in the superior-peripheral area than in other areas. A slight intergroup difference was noted in terms of the F-S CET at the paracentral (0.11 ± 0.93 vs 0.32 ± 0.92, P = .038), midperipheral (0.45 ± 0.78 vs 0.77 ± 0.89, P = .001), and peripheral (3.11 ± 2.18 vs 4.10 ± 2.38, P < .001) zone. In each zone, the difference in F-S CET between the two groups was less than 1 μm. As the area expanded, the F-S CET continued to increase ( F = 850.303, P < .001). A weak correlation was observed between F-S CET and corneal toricity ( r = 0.103 to 0.240); however, this correlation was not significant in the paracentral zone. Covariance analysis demonstrated that F-S CET was slightly correlated with age, refractive state, and intraocular pressure. Conclusions: The corneal toricity did not significantly affect the distribution of the corneal epithelium in normal corneas. [ J Refract Surg . 2023;39(7):482–490.]

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The Influence of Tomographic Corneal Characteristics on Epithelial Thickness Profile

Cited by 3 publications

References 13 publications

Corneal Epithelial Thickness Mapping: A Major Review

Corneal Epithelial Thickness Mapping: A Major Review

Repeatability of Corneal Epithelial Thickness Map Using Anterior-Segment Optical Coherence Tomography in Normal and Corneal Disease Patients

Impact of Corneal Toricity on the Distribution of Corneal Epithelial Thickness

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