Pentacam HR Indices Variation in Normal Corneas with Different Corneal Thickness

Roshdy, Maged Maher Salib; Wahba, Sherine S; Elkitkat, Rania Serag; Madkour, Nermine Said Aly; Fikry, Ramy Riad

doi:10.1155/2018/9328120

Cited by 5 publications

(9 citation statements)

References 30 publications

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“…e human eye has a very complex structure, of which the cornea, located at the very front of the eye, is composed of transparent tissue that not only protects the eye but also provides 70% of the refractive index of the eye [1] and is the main refractive medium of the human eye, which means that small changes in the morphology of the cornea can lead to significant changes in the optical properties of the whole eye. Corneal diseases such as cone keratoconus, dilatation [2], and keratoconus surgery [3] can all lead to significant changes in the optical properties of the cornea.…”

Section: Introductionmentioning

confidence: 99%

Visual Corneal Photomechanical Analysis Is Combined with the Pentacam Correlation Index for the Diagnosis of Cone Corneas at Different Stages of Progression

Cheng

Zhang

Tian

et al. 2022

Journal of Healthcare Engineering

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Cone-shaped corneas are blinding eye diseases characterised by dilated and thinning corneal tissue and forward conical protrusions, most often in adolescents. Early detection and intervention can prevent further dilatation of the cornea. The prevailing examination methods and techniques are not difficult to diagnose clinical cone corneas, but there are limitations in the diagnosis of early cone corneas (static cone corneas and subclinical cone corneas). In this study, we investigated the diagnostic value of the combination of these two instruments in the diagnosis of clinical cone corneas and subclinical cone corneas by performing the Pentacam and Corvis ST examinations in healthy eyes and dystrophic cone corneas. This study provides a theoretical basis for early cone cornea screening and diagnosis. The analysis revealed that only TP, SPA1, ARTh, and bIOP were normally distributed among all included parameters, and only bIOP was normally distributed with equal variance. TBI and CBI indices have a certain sensitivity and specificity for the diagnosis of subclinical cone corneas, with a strong diagnostic ability, and can be used for screening and early diagnosis of cone corneas.

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Section: Introductionmentioning

confidence: 99%

Visual Corneal Photomechanical Analysis Is Combined with the Pentacam Correlation Index for the Diagnosis of Cone Corneas at Different Stages of Progression

Cheng

Zhang

Tian

et al. 2022

Journal of Healthcare Engineering

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“… 24 Roshdy et al . 7 reported higher back elevation of the thinnest point in thick corneas than thin and average ones. It contradicts our result without a significant difference between groups in terms of back and front elevations.…”

Section: Discussionmentioning

confidence: 88%

“…Roshdy et al . 7 showed that thinner corneas had a PPI-max greater than that of thicker corneas. On the contrary, ART-max increased with the increase in thickness.…”

Section: Discussionmentioning

confidence: 99%

“… 7 reported different back elevation and pachymetric-based measures including pachymetry progression indices (PPIs) and Ambrosio's relational thickness (ART) among thin, average, and thick healthy corneas, although they did not evaluate other parameters of Belin-Ambrósio Enhanced Ectasia Display (BAD) such as deviation indices and keratoconus indices as well as specificity of these indices based on routine cut-off values. 7 Indeed, it is predicted that various corneal thicknesses have different pachymetric-based indices, while the question remains unanswered whether they differ in terms of normalized indices as well. The specificities of Pentacam indices in various corneal thicknesses are another ambiguous issue by considering nonconsensual protocols, especially for subjects with preclinical keratoconus who have overlap with normal subjects in terms of corneal thickness.…”

Section: Introductionmentioning

confidence: 99%

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Comparing Pentacam Hr Screening Indices in Different Normal Corneal Thicknesses Among Refractive Surgery Candidates

Abdolalizadeh

Ghiasian

Hadavandkhani

et al. 2022

Journal of Current Ophthalmology

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Purpose: To compare Pentacam indices in normal eyes with different corneal thicknesses. Methods: It is a retrospective observational study. Ninety-six normal eyes of 96 patients who were referred for refractive surgery in a tertiary university-based hospital from October 2015 to April 2019 were recruited consecutively. Corneal keratometry as well as Pentacam's software Belin-Ambrósio Enhanced Ectasia Display (BAD) parameters including pachymetry progression indices (PPIs), maximum Ambrosio's relational thickness (ART-max), corneal elevations, normalized deviations, BAD total deviation value (BAD-D), and anterior surface indices were measured by Pentacam HR (Type 70900). The included were classified as thin (26 eyes), average (45 eyes), and thick (25 eyes) corneas with the thinnest point thickness of ≤496 μm, 497–595 μm, and ≥596 μm, respectively. The specificities of all parameters were calculated based on routine cut-off values. Results: The refraction, keratometry, and elevations were not different ( P > 0.05). All PPIs (minimum, average, and maximum) of thick corneas were significantly lower than average and thin corneas ( P < 0.001). ART-max increased by thickening of the cornea ( P < 0.001). BAD-D score and normalized indices of pachymetric parameters decreased with the increase of thickness ( P < 0.001), while specificities of all indices increased with corneal thickening. More than 96% of thick corneas were classified as normal PPI-max (24/25), ART-max (25/25), and BAD-D (25/25), while nearly <54% of thin corneas (14/26 for PPI-max, 9/26 for ART-max, and 12/26 for BAD-D) were normal. Conclusions: The pachymetry-related indices and BAD-D were different among normal corneas with various thicknesses. The specificities of PPIs, ART-max, and BAD-D of thin corneas were lower than in thick corneas.

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“…On the contrary, BFTE has been recommended for use by other studies, as they concluded that toric ellipsoid reference surface is the most sensitive reference body to compare KC to normal corneas. Roshdy et al (10) . reported that posterior elevation from both 8mm BFS and BFTE had the highest AUROC (0.983 and 0.986, respectively).…”

Section: Discussionmentioning

confidence: 99%

Corneal Elevation Changes in Normal Population and Keratoconus Patients Using Different Acquisition Diameters with Scheimpflug Imager

Elgouhary

Elkawi

Elaziz

2021

The Egyptian Journal of Hospital Medicine

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Background: Keratoconus is a bilateral, progressive, noninflammatory disease of the cornea which often leads to high myopia and astigmatism with an estimated prevalence of approximately 1 in 2000. Objective: To detect the changes in corneal elevation values using different acquisition diameters (8, 9 mm) in both normal population and keratoconus patients. Patients and Methods: This is a cross-sectional clinical trial conducted at the Ophthalmology Department, Menoufia University Hospital, and Tiba eye center, Menoufia, Egypt in the period between January 2019 to December 2020. Two hundred corneas of two hundred subjects were involved and categorized into two groups, a control group with normal cornea100 subjects (group A) and a group with keratoconus100 subjects (group B) both confirmed by clinical examination and pentacam readings. Results: Receiver operating curve (ROC) analysis was conducted to identify the optimal elevation front parameters levels for prediction of keratoconus. The best cut-off values for front parameters BFS 8mm, BFS 9mm, BFTE 8mm and BFTE 9mm were 6.5, 10.5,2.5,2.5 with (96%,92%,92%,92% sensitivity, and 96%,96%,80%, 72% specificity), respectively. Also, the best cut-off values for back parameters levels for prediction of keratoconus for BFS 8mm, BFS 9mm, BFTE 8mm and BFTE 9mm were 14.0, 25.5, 6.5 and 9.5 mm with (96%, 96%, 80%, 72% sensitivity, and 88%, 96%, 64%, 88% specificity), respectively. Conclusion:We can conclude that there was a significant increase in elevation back parameters in keratoconus patients compared to control. The best cut-off values for front parameters levels as BFS (8, 9mm) and BFTE (8, 9 mm) was 6.5, 10.5, 2.5, and 2.5 mm, respectively.

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Pentacam HR Indices Variation in Normal Corneas with Different Corneal Thickness

Cited by 5 publications

References 30 publications

Visual Corneal Photomechanical Analysis Is Combined with the Pentacam Correlation Index for the Diagnosis of Cone Corneas at Different Stages of Progression

Visual Corneal Photomechanical Analysis Is Combined with the Pentacam Correlation Index for the Diagnosis of Cone Corneas at Different Stages of Progression

Comparing Pentacam Hr Screening Indices in Different Normal Corneal Thicknesses Among Refractive Surgery Candidates

Corneal Elevation Changes in Normal Population and Keratoconus Patients Using Different Acquisition Diameters with Scheimpflug Imager

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