Comparison of Scheimpflug imaging parameters between steep and keratoconic corneas of Caucasian eyes

Huseynova, Tukezban; Abdulaliyeva, Farah; Lanza, Michele

doi:10.2147/opth.s102683

Cited by 7 publications

(3 citation statements)

References 21 publications

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“…However, the association of refractive errors with CKI, KI, and IHD indices was not significant. A review of the literature revealed no similar data in this regard, despite the study by Brizl et al [ 31 ], who showed the same data as ours. In patients without keratoconus (KC) disorder, the mean ISV in 36 eye samples was 21.83±8.03, their mean of IVA was 0.12±0.04, with a mean IHA of 5.02±4.29, and R min of 7.18±0.17.…”

Section: Discussionsupporting

confidence: 45%

A comparative study of Pentacam indices in various types and severities of refractive error in candidates for photorefractive keratectomy (PRK) surgery

et al. 2022

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This study aimed to specify Pentacam indices in patients who suffered from different types of refractive error and underwent photorefractive keratectomy (PRK) surgery. It is a descriptive cross-sectional study carried out on 1125 patients (2215 eye samples) who underwent PRK surgery in the Noor Surgical Center of Ardabil, Iran, over a 5 year period (2014–2018). A particular checklist was provided to patients, which consisted of demographic data, pachymetry test, keratometry, refractive error, corneal-thickness indices, and corneal surface area indices. The data were analysed using the statistical analysis package of IBM® V25. The mean age of the participants in this study was 28.48±6.82 years, and the ratio of women to men was 66.4%. It was observed that the differences between angle, volume, the depth of the anterior chamber, IVA, and ISV were significant (P=0.00) when compared to each other in all types of refractive errors. High myopes had significantly higher Kmax front than low myopes (P=0.00). In astigmatism patients, the Kmax in front of the cornea in extreme type was significantly higher than in moderate (P=0.00) and high (P=0.01) types. High myopes had significantly lower Rmin than mild myopes (P=0.02), and extreme astigmatism had significantly lower Rmin than high (P=0.014) and moderate types (P=0.013). The data from this study revealed that in patients undergoing PRK surgery, some Pentacam indices could be related to some types of refractive error, and in some of these indices, there are statistically significant differences between different severities of refractive errors. Therefore, their preoperative evaluation is very important.

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Section: Discussionsupporting

confidence: 45%

A comparative study of Pentacam indices in various types and severities of refractive error in candidates for photorefractive keratectomy (PRK) surgery

et al. 2022

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“… Pentacam (Oculus Optikgerate GmbH, Wetzlar, Germany) Nil Henriquez et al, 2012 29 Peru Out-patients 151 28.4, 29.29 The study group was defined as keratoconus in both eyes, with the presence of clinical signs and topographic evaluation while the control group were subjects who had normal corneas in both eyes. Scheimpflug Imaging Analyzer (Pentacam; Oculus GmBH, Wetzlar, Germany) Not stated Huseynova et al, 2016 30 Azerbaijan Out-patients 85 23.77, 26.06 The study group were eyes with keratoconus while the control group were healthy corneas diagnosed according to Amsler–Krumeich criteria. 31 Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany Not stated Koc et al, 2020 32 Turkey Out-patients 402 26, 24.8 The diagnosis of clinical keratoconus was defined by characteristic keratoconus signs in the anterior sagittal curvature maps while the control group was randomly selected from a database of age-matched candidates’ laser in situ keratomileusis (LASIK) for myopia (≤5.0 D) and myopic astigmatism (≤3.0 D) who had normal topographic, topometric and tomographic analysis and did not develop ectasia after at least 1-year follow-up.…”

Section: Resultsmentioning

confidence: 99%

Scheimpflug-Derived Keratometric, Pachymetric and Pachymetric Progression Indices in the Diagnosis of Keratoconus: A Systematic Review and Meta-Analysis

Owusu,

Zaabaar,

Kwarteng

et al. 2023

OPTH

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Scheimpflug Pentacam Tomography is becoming crucial in the diagnosis and monitoring of keratoconus, as well as in pre- and post-corneal refractive care, but there are still some inconsistencies surrounding its evidence base diagnostic outcome. Therefore, this study aimed at employing meta-analysis to systematically evaluate the keratometric, pachymetric, and pachymetric progression indices used in the diagnosis of Keratoconus. The review protocol was registered with PROSPERO (Identifier: CRD4202310058) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, MEDLINE, Web of Science, and EMBASE were used for data search, followed by a quality appraisal of the included studies using the revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Meta-analysis was conducted using the meta (6.5.0) and metafor (4.2.0) packages in R version 4.3.0, as well as Stata. A total of 32 studies were included in the analysis. All keratometry (K) readings (flattest meridian, K1; steepest meridian, K2, maximum, Kmax) were significantly steeper in keratoconic compared to normal eyes: [MD (95% CI)], K1 [2.67 (1.81; 3.52)], K1-back [−0.71 (−1.03; −0.39)], K1-front [4.06 (2.48; 5.63)], K2 [4.32 (2.89; 5.75)], K2-back [−1.25 (−1.68; −0.82)], K2-front [4.82 (1.88; 7.76)], Kmax [7.57 (4.80; 10.34)], and Kmean [2.80 (1.13; 4.47)]. Additionally, corneal thickness at the center, CCT [−61.19 (−73.79; −48.60)] and apex, pachy-apex [−41.86 (−72.64; −11.08)] were significantly thinner in keratoconic eyes compared to normal eyes. The pooled estimates for pachymetric progression index (PPI): PPImin [0.66 (0.43; 0.90)], PPImax [1.26 (0.87; 1.64)], PPIavg [0.90 (0.68; 1.12)], and Ambrosio relational thickness (ART): ARTmax [−242.77 (−288.86; −196.69)], and ARTavg [−251.08 (−308.76; −195.39)] revealed significantly more rapid pachymetric progression in keratoconic eyes than in normal eyes. The Pentacam Scheimpflug-derived keratometric, pachymetric, and pachymetric progression indices are good predictors in discriminating KC from normal eyes.

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“…The same ophthalmologist (Y.K) performed all the measurements. Topography images were taken using the Pentacam, which enabled images to be taken of the anterior and posterior surfaces of the cornea and iris, and of the anterior and posterior surfaces of the lens in a movable virtual eye (9) . After positioning the participant's head in a chin rest and head rest, the participant was asked to fixate on the center of the blue slit light.…”

Section: Evaluation Of Anterior Segment Parameters Usingmentioning

confidence: 99%

Evaluation of anterior segment parameters using Scheimpflug technology during the Valsalva maneuver in patients with keratoconus

Koçluk¹,

Sukgen²,

Cevher³

2016

Arquivos Brasileiros De Oftalmologia

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Keratoconus (KC) is a noninflammatory eye condition characterized by progressive corneal ectasia, myopia, and irregular astigmatism, generally with bilateral involvement. The etiology and progression of keratoconus have been closely linked to genetic factors, which appear to be multifactorial. However, the majority of cases are not linked to genetic factors (1,2) . It is important to detect progression in KC before making collagen cross-linking (CXL).The Valsalva maneuver (VM) is an attempt at a powerful exhalation against a closed airway. VM is frequently performed during normal daily activities: examples include lifting heavy items, performing physical exercise, vomiting, and coughing. Various physiological changes happen during these activities, including elevated blood pressure, increased intrathoracic pressure, increased peripheral venous pressure, ABSTRACTPurpose: This study aimed to explore the effects of the Valsalva maneuver (VM) on ectatic corneas during anterior segment tomography scans using a Scheimpflug camera. Methods: This prospective observational study included 100 eyes of 50 patients with bilateral keratoconus (KC). Anterior segment tomography was first performed when the patients were in a resting position and immediately repeated as the participant performed VM. Scheimpflug images were taken using a Pentacam®. Results: The mean age of the participants was 24.14 ± 6.59 years. Of the 100 eyes included in the study, 7% had stage 1 KC, 47% had stage 2 KC, 32% had stage 3 KC, and 14% had stage 4 KC. The indices of KC were not significantly affected by VM. Similarly, no statistically significant differences were found between the stages of KC, or with the mean pachymetric progression index during VM. Pupil diameter showed a statistically significant increase during VM (p=0.017). There was a statistically significant decrease in the anterior chamber angle measurement during VM (p=0.001). Maximum curvature power in the front of the cornea decreased more during VM in stage 4 KC than for the other stages (p=0.014). Conclusions:No changes associated with VM were found in the KC indices or the stage of the disease. However, an increase in pupil diameter and a decrease in anterior chamber angle value were found. These changes were comparable to values obtained from previous studies performed on normal corneas.

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Comparison of Scheimpflug imaging parameters between steep and keratoconic corneas of Caucasian eyes

Cited by 7 publications

References 21 publications

A comparative study of Pentacam indices in various types and severities of refractive error in candidates for photorefractive keratectomy (PRK) surgery

A comparative study of Pentacam indices in various types and severities of refractive error in candidates for photorefractive keratectomy (PRK) surgery

Scheimpflug-Derived Keratometric, Pachymetric and Pachymetric Progression Indices in the Diagnosis of Keratoconus: A Systematic Review and Meta-Analysis

Evaluation of anterior segment parameters using Scheimpflug technology during the Valsalva maneuver in patients with keratoconus

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