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JAYPEE JOURNALS
International Scientific Journals from Jaypee
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1.  Review Article
Reevaluating the Effectiveness of Corneal Collagen Cross-linking and Its True Biomechanical Effect in Human Eyes
Damien Gatinel
[Year:2017] [Month:January-June] [Volume:6 ] [Number:1] [Pages:44] [Pages No:34-41] [No of Hits : 878]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1140 | FREE

ABSTRACT

The induction of cross-links in corneal tissue appears to be a promising technique to increase its stiffness and this has been the basis of treatment of keratoconus (KC) and corneal ectatic disease. However, there exists a striking discrepancy between the reported biomechanical effects of corneal collagen cross-linking (CXL) in vitro compared to in vivo, and this has not received much attention in the literature.
Despite the documentation of an increase in corneal stiffness in vitro by many investigators, reports that provide evidence of measurable and consistent biomechanical changes in corneal rigidity in vivo after CXL are lacking. Indeed, the absence of documented in vivo biomechanical improvement in CXL-treated corneas is a conundrum, which needs to be further explored. To explain this discrepancy, it has been postulated that biomechanical changes induced by CXL are too subtle to be measured by currently available diagnostic tools or have characteristics not discernible by these technologies. However, the dynamic bidirectional applanation device (Ocular Response Analyzer) and dynamic Scheimpflug analyzer instruments (Corvis ST) have demonstrated the ability to quantify even subtle biomechanical differences in untreated KC corneas of different ectatic degree, and document the reduction in corneal hysteresis (CH) and corneal resistance factor (CRF) in situations where the corneal stiffness is reduced, such as after laser in situ keratomileusis and surface ablation procedures. It has also been possible to demonstrate an altered CH and CRF in patients with diabetes, smoking habit, glaucoma, Fuchs’ dystrophy, and corneal edema. It is puzzling that these diagnostic tools could document subtle biomechanical changes in these situations, yet fail to measure the purported changes induced by CXL on corneas with progressive KC. This failure to document significant and consistent biomechanical changes in corneal rigidity could suggest that CXL does not induce a simple reversal of the particular biomechanical deficits that characterize KC, or make the cornea significantly more resistant to bending forces as has been widely postulated. The absence of measurable biomechanical change in living KC corneas after CXL could be a consequence of biomechanical strengthening which is insignificant compared to the marked weakening caused by preexisting alteration of the collagen structure, disorganization of collagen fiber intertwining, and compromised structural-mechanical homogeneity that are hallmarks of keratoconic disease, especially in corneas with progressive KC.
The changes in the cornea induced by CXL that have been described in vivo may instead be driven by a wound healing process in response to the removal of the corneal epithelial layer and subsequent exposure to riboflavin and ultraviolet-A (UVA). This paper will present evidence that sustains this hypothesis.

Keywords: Corneal biomechanics, Corneal epithelium, Crosslinking, Ectasia, Hysteresis, Keratoconus.

How to cite this article: Gatinel D. Reevaluating the Effectiveness of Corneal Collagen Cross-linking and Its True Biomechanical Effect in Human Eyes. Int J Kerat Ect Cor Dis 2017;6(1):34-41.

Source of support: Nil

Conflict of interest: None

 
2.  Review Article
Eye Rubbing, a Sine Qua Non for Keratoconus?
Damien Gatinel
[Year:2016] [Month:January-April] [Volume:5 ] [Number:1] [Pages:51] [Pages No:6-12] [No of Hits : 3124]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1114 | FREE

ABSTRACT

Keratoconus, a dystrophy of unknown origin, remains an ophthalmic enigma. The contrast between the presence of marked structural changes and deformation of the corneal wall and the relative absence of specific genetic and biomolecular findings continues to intrigue ophthalmologists. In Marfan syndrome, where genetic and molecular abnormalities are well identified, and similar changes in collagen observed, the cornea tends not to be steeper, irregular or ectatic, but are globally flatter. This suggests that an external mechanical force may be necessary to induce the apparition and progression of the ectatic process in keratoconus. Eye rubbing has long been acknowledged as a risk factor for keratoconus and its progression, but could it in fact be the root cause? Many clinical observations and reports support the hypothesis of eye rubbing as a first and necessary hit for inducing progressive ectatic deformation of the corneal wall. Validating or refuting this hypothesis on the basis of patient admission may be impossible. It is difficult to document the frequency, duration and intensity of eye rubbing in patients with keratoconus, and virtually impossible to prove that every patient who denies the habit truly does not rub his eyes. Both the increase in incidence of atopy and the time spent in front of the computer screen in the general population may account for an increased tendency for eye rubbing, and lead to the perceived increased prevalence of keratoconus in both urban and non-urban areas. This paper explores the possibility that the mechanical stress imposed on the cornea by rubbing may not be as much a second hit evoking the structural changes of a predisposed cornea exhibiting unknown collagen progressive alteration, but rather the necessary trigger and sine qua non of the keratoconic process. Even if this provocative hypothesis is impossible to prove, it is equally difficult to refute, and acknowledging eye rubbing as a possible root cause increases awareness within the general population and if true, could dramatically reduce the incidence of keratoconus, and halt its progression in eyes already affected.

Keywords: Computer vision syndrome, Corneal biomechanics, Crosslinking, Ectasia, Eye rubbing, Etiology of keratoconus, Keraotoconus, Marfan syndrome.

How to cite this article: Gatinel D. Eye Rubbing, a Sine Qua Non for Keratoconus? Int J Kerat Ect Cor Dis 2016;5(1):6-12.

Source of support: I thank Cordelia Chan, MD, for assisting the revision of the manuscript.

Conflict of interest: None

 
3.  
Keratoconus Management Guidelines
Jorge L Alió, Alfredo Vega-Estrada, Pablo Sanz-Díez, Pablo Peña-García, María Luisa Durán-García, Miguel Maldonado
[Year:2015] [Month:January-April] [Volume:4 ] [Number:1] [Pages:39] [Pages No:1-39] [No of Hits : 6133]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1095 | FREE

ABSTRACT

This study was partly financed by a project of the Spanish Ministry of Economy and Competitiveness, the Carlos III Health Institute and the Cooperative Health Research Thematic Network on ‘Age-related Eye Disease, Visual Quality and Quality-of-Life’, sub-project ‘Visual Quality’ (RD07/0062); and another project of the Spanish Ministry for Economy and Competitiveness, the Carlos III Health Institute, the Cooperative Health Research Thematic Network ‘Prevention, Early Detection and Treatment of Prevalent, Degenerative and Chronic Eye Diseases’, sub-program ‘Ocular Structures and Common Pathologies’ (RD12/0034).

 
4.  Original Article
A New Tomographic Method of Staging/Classifying Keratoconus: The ABCD Grading System
Michael W Belin, Josh Duncan, Renato Ambrósio Jr, José AP Gomes
[Year:2015] [Month:September-December] [Volume:4 ] [Number:3] [Pages:37] [Pages No:85-93] [No of Hits : 1718]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1105 | FREE

ABSTRACT

Purpose: To incorporate advanced corneal imaging into a new keratoconus classification system that utilizes posterior curvature, thinnest pachymetry, and best-corrected distance vision (CDVA) in addition to standard anterior parameters.

Materials and methods: A total of 672 eyes of 336 normal patients were imaged with the Oculus Pentacam HR. Anterior and posterior radius of curvature measurements were taken using a 3.0 mm zone centered on the thinnest area and corneal thickness was measured at the thinnest point. Mean and standard deviations were recorded and anterior data were compared to the existing Amsler-Krumeich (AK) classification.

Results: A total of 672 eyes of 336 patients were analyzed. Anterior and posterior values were 7.65 ± 0.236 mm / 6.26 ± 0.214 mm respectively and thinnest pachymetry values were 534.2 ± 30.36 um. Comparing anterior curvature values to AK staging yielded 2.63, 5.47, 6.44 standard deviations for stages 1, 2, and 3 respectively. Posterior staging uses the same standard deviation gates. Comparative pachymetric values yielded 4.42, and 7.72 standard deviations for stages 2 and 3 respectively.

Conclusion: A new keratoconus staging system incorporates posterior curvature, thinnest pachymetric values, and distance visual acuity in addition to the standard anterior curvature and consists of stages 0 to 4 (5 stages), closely matches the existing AK classification stages 1 to 4 on anterior curvature. The new classification system by incorporating curvature and thickness measurements based on the thinnest point, as opposed to apical, better reflects the anatomic changes in keratoconus.

Keywords: Classification, Ectasia, Keratoconus, Radius of curvature.

How to cite this article: Belin MW, Duncan J, Ambrósio R Jr, Gomes JAP. A New Tomographic Method of Staging/ Classifying Keratoconus: The ABCD Grading System. Int J Kerat Ect Cor Dis 2015;4(3):85-93.

Source of support: Nil

Conflict of interest: None

 
5.  CASE REPORT
Corneal Collagen Cross-linking in a Prepubescent 10-Year-Old Girl with Aggressive Keratoconus
Marco Abbondanza, Margherita Guidobaldi
[Year:2015] [Month:May-August] [Volume:4 ] [Number:2] [Pages:42] [Pages No:63-65] [No of Hits : 1201]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1101 | FREE

ABSTRACT

Keratoconus (KC) is a corneal ectatic disease that results in bilateral and asymmetrical corneal distortion, altered refractive powers and reduced vision. In 20 to 25% of cases, corneal transplantation may be required, although a number of conservative procedures are available. We report a case of an aggressive stage II keratoconus in a prepubescent 10-year-old girl, successfully treated with corneal collagen cross-linking (CXL) with epithelium removal.

Keywords: Cornea, Corneal collagen cross-linking, Keratoconus, Pediatric.

How to cite this article: Abbondanza M, Guidobaldi M. Corneal Collagen Cross-linking in a Prepubescent 10-Year- Old Girl with Aggressive Keratoconus. Int J Kerat Ect Cor Dis 2015;4(2):63-65.

Source of support: Nil

Conflict of interest: None

 
6.  Review Article
Collagen Cross-linking for Pellucid Marginal Degeneration
Cheryl MacGregor, Rakesh Jayaswal, Nick Maycock
[Year:2015] [Month:September-December] [Volume:4 ] [Number:3] [Pages:37] [Pages No:100-102] [No of Hits : 991]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1107 | FREE

ABSTRACT

Pellucid marginal degeneration (PMD) is a rare progressive condition resulting in inferior corneal thinning and astigmatism. Alongside keratoconus and keratoglobus, it is considered one of noninflammatory corneal ectasias. The focus of corneal thinning is greatest inferiorly resulting in diminished visual acuity and overall reduction in visual quality. Traditional methods of treatment or disease management have been similar to those proposed for keratoconus, contact lenses, escalating to intrastromal rings, lamellar keratoplasty or penetrating keratoplasty.
Collagen cross-linking (CXL) has steadily gained acceptance as the treatment of choice for progressive corneal ectasias. Although it has been described at length for keratoconus, there is little literature describing or advocating its use in PMD. In this article, we will review the evidence for CXL and its use in PMD.

Keywords: Cornea, Corneal collagen cross-linking, Pellucid marginal degeneration, Review article.

How to cite this article: MacGregor C, Jayaswal R, Maycock N. Collagen Cross-linking for Pellucid Marginal Degeneration. Int J Kerat Ect Cor Dis 2015;4(3):100-102.

Source of support: Nil

Conflict of interest: None

 
7.  Case Report
Surgical Correction of an Inverse Astigmatic Keratotomy following Penetrating Keratoplasty in a Patient with Keratoconus
Marco Abbondanza, Gabriele Abbondanza
[Year:2015] [Month:September-December] [Volume:4 ] [Number:3] [Pages:37] [Pages No:107-109] [No of Hits : 870]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1109 | FREE

ABSTRACT

Astigmatic keratotomy (AK) is a common and safe procedure to correct post-penetrating keratoplasty (PKP) astigmatism in patients affected by keratoconus (KC). We report the case of a post-PKP AK that was performed inversely by mistake in a private practice. A new AK was performed by our practice in order to correct the remarkably high astigmatism (19 D) that was created with the previous inverse procedure. Fourteen months later, astigmatism had decreased by 12.9 D and central corneal thickness had increased by 35 µm.

Keywords: Astigmatic keratotomy, Cornea, Keratoconus, Keratotomy, Lri, Surgical error.

How to cite this article: Abbondanza M, Abbondanza G. Surgical Correction of an Inverse Astigmatic Keratotomy following Penetrating Keratoplasty in a Patient with Keratoconus. Int J Kerat Ect Cor Dis 2015;4(3):107-109.

Source of support: Nil

Conflict of interest: None

 
8.  CASE REPORT
Long-term Stability of Ectasia in a Young Patient with Asymmetric Keratoconus
Rosane de Oliveira Corrêa, Ana Laura Caiado Canedo, Rozalia Beildeck, Marcella Quaresma Salomão, Penelope Burle de Politis, Renato Ambrósio Jr
[Year:2015] [Month:May-August] [Volume:4 ] [Number:2] [Pages:42] [Pages No:66-68] [No of Hits : 830]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1102 | FREE

ABSTRACT

Purpose: To report the clinical course of a typical young patient presenting with asymmetric keratoconus (KC), that demonstrates that stabilization of the ectatic process is possible without cross-linking (CXL) procedure.

Methods: Case report and review of the literature.

Results: A 17-year-old male patient was referred due to the diagnosis of keratoconus. Patient complained of loss of vision in the left eye (OS). Uncorrected distance visual acuity (UDVA) was 20/25+ in the right eye (OD) and 20/80 in the left eye; wavefront-assisted manifest refraction gave best corrected distance visual acuity (CDVA) of 20/20 in OD and 20/40 in OS. The diagnosis of keratoconus was confirmed with Placido disk-based topography (Oculus Keratograph 4), and Pentacam HR corneal tomography (Oculus Optikgeräte GmbH, Wetzlar, Germany). Femtosecond laser-assisted intracorneal ring segment (ICRS) implantation was performed in the left eye and treatment for allergy was prescribed for both eyes, along with patient education and advice not to rub the eyes. After 3 months, significant improvement was observed on UDVA (20/30) and CDVA (20/20) in the left eye. Topometric and tomographic stability of ectasia was observed in the right eye in a 4-year follow-up.

Conclusion: Intracorneal ring segment caused significant regularization of the corneal shape and improvement on visual acuity. Ectasia stability was achieved with no need for CXL, despite the patient’s young age. This case raises the point that the indication of CXL for every keratoconic patient should be reconsidered.

Keywords: Cross-linking indication, Intracorneal ring, Keratoconus.

How to cite this article: de Oliveira Correa R, Canedo ALC, Beildeck R, Salomão MQ, de Politis PB, Ambrósio R Jr. Longterm Stability of Ectasia in a Young Patient with Asymmetric Keratoconus. Int J Kerat Ect Cor Dis 2015;4(2):66-68.

Source of support: Nil

Conflict of interest: Dr Ambrósio is a consulant for oculus and wavelight-alcon.

 
9.  REVIEW ARTICLE
Corneal Hydrops in Keratoconus
Prafulla K Maharana, Ritu Nagpal, Namrata Sharma
[Year:2015] [Month:May-August] [Volume:4 ] [Number:2] [Pages:42] [Pages No:52-55] [No of Hits : 590]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1098 | FREE

ABSTRACT

Purpose: The purpose of this review is to outline the etiology, clinical features, and management of acute corneal hydrops (CH) in cases of keratoconus (KC).

Recent findings: The advent of newer investigative modalities like ultra biomicroscopy, anterior segment optical coherence tomography and confocal microscopy has contributed toward the diagnosis, treatment planning and following the course of therapy in cases of acute hydrops.

Summary: Corneal hydrops is an acute complication of keratoconus which in most instances resolves spontaneously. However, prolonged corneal edema can lead to complications, such as corneal neovascularization which can jeopardise a future corneal graft. Hence, timely intervention is required in most cases to prevent such complications as well as for early visual rehabilitation. Intracameral gas injection is the most commonly performed surgical procedure for hydrops. Modifications in surgical technique can help to tackle difficult situations.

Keywords: Acute corneal hydrops, Corneal edema, Intracameral gas injection, Keratoconus.

How to cite this article: Maharana PK, Nagpal R, Sharma N. Corneal Hydrops in Keratoconus. Int J Kerat Ect Cor Dis 2015;4(2):52-55.

Source of support: Nil

Conflict of interest: None

 
10.  Original Article
Prevalence of Keratoconus among Young Arab Students in Israel
Einat Shneor, Michel Millodot, Ariela Gordon-Shaag, Maron Essa, Miriam Anton, Ramez Barbara, Adel Barbara
[Year:2014] [Month:January-April] [Volume:3 ] [Number:1] [Pages:51] [Pages No:9-14] [No of Hits : 2684]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1070 | FREE

ABSTRACT

Purpose: To determine the prevalence of keratoconus (KC) in an Arab population in Israel.

Materials and methods: Videokeratography was performed on volunteer students from the Academic Arab College of Education, in Haifa, Israel. All participants filled out a selfadministered questionnaire to evaluate possible risk factors for KC. Univariate and multivariate analysis were performed.

Results: Data of 314 participants were analyzed and a prevalence of (N = 10), 3.18% (95% CI, 1.2 to 5.1%) was found. The only significant factor (both in univariate and multivariate analysis) that was associated with KC was parental consanguinity (OR 5.10, p = 0.02). Druzes and Bedouins had a higher prevalence than Muslims and Christians. However, the differences were not significant possibly due to the small size of the sample.

Conclusion: The result of this study was similar to other studies conducted in the Middle East, which indicate a higher prevalence of KC than in western countries. It is also recommended that people who have consanguinity in their family should be topographically tested to detect the early stages of KC.

Keywords: Keratoconus, Consanguinity, Videokeratography.

How to cite this article: Shneor E, Millodot M, Gordon-Shaag A, Essa M, Anton M, Barbara R, Barbara A. Prevalence of Keratoconus among Young Arab Students in Israel. Int J Kerat Ect Cor Dis 2014;3(1):9-14.

Source of support: Nil

Conflict of interest: None declared

 
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