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JAYPEE JOURNALS
International Scientific Journals from Jaypee
Joseph Colin Keratoconus Award
IndexCopernicus Value: 83.60
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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 : 1352]
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.  Original Article
Assessing Progression of Keratoconus and Cross-linking Efficacy: The Belin ABCD Progression Display
Michael W Belin, Jay J Meyer, Josh K Duncan, Rachel Gelman, Mark Borgstrom, Renato Ambrósio Jr
[Year:2017] [Month:January-June] [Volume:6 ] [Number:1] [Pages:44] [Pages No:1-10] [No of Hits : 689]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1135 | FREE

ABSTRACT

Several methods have been described to both evaluate and document progression in keratoconus and to show efficacy of cross-linking, however, there are no consistent generally accepted parameters. Modern corneal tomography, including both anterior and posterior elevation and pachymetric data can be used to screen for ectatic progression, be employed to detect earlier change and additionally to show efficacy of new treatment modalities, such as crosslinking.
To describe specific quantitative values that can be used as progression and efficacy determinants, the normal noise measurements of the three parameters used in the ABCD keratoconus classification (corneal thickness at the thinnest point, anterior and posterior radius of curvature taken from the 3.0 mm optical zone centered on the thinnest point), were determined. Values were obtained from both a normal population and a known keratoconic population. The 80 and 95% one-sided confidence intervals for all three parameters were surprisingly small, suggesting that they may perform well as progression and efficacy determinants.

Keywords: Collagen cross-linking, Ectatic disease, Keratoconus, Tomography, Topography.

How to cite this article: B elin M W, M eyer J J, D uncan J K, Gelman R, Borgstrom M, Ambrósio Jr R. Assessing Progression of Keratoconus and Cross-linking Efficacy: The Belin ABCD Progression Display. Int J Kerat Ect Cor Dis 2017;6(1):1-10.

Source of support: Nil

Conflict of interest: None

 
3.  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 : 3674]
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

 
4.  Review Article
Progression in Keratoconus
Paolo Vinciguerra, Raffaele Piscopo, Fabrizio Camesasca, Riccardo Vinciguerra
[Year:2016] [Month:January-April] [Volume:5 ] [Number:1] [Pages:51] [Pages No:21-31] [No of Hits : 722]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1117 | FREE

ABSTRACT

The study of keratoconus progression was once based upon slitlamp study, keratometry, and placido disk image examination. Today we have a lot of new corneal devices and indexes wich can help the ophthalmologist to make earlier the diagnosis and also to recognize as much is possible a progressive keratoconus. Only a deep knowledge of the meaning of all these indexes and values, together with the ability to interlock one another, increases reliability in the evaluation of Corneal Ectasia. Some pratical instructions are provided to help the early diagnosis of progressive Keratoconus.

Keywords: Corneal tomography, Corneal topography, Ectasia, Keratoconus.

How to cite this article: Vinciguerra P, Piscopo R, Camesasca F, Vinciguerra R. Progression in Keratoconus. Int J Kerat Ect Cor Dis 2016;5(1):21-31.

Source of support: Nil

Conflict of interest: None

 
5.  Case Report
Unilateral Ectasia characterized by Advanced Diagnostic Tests
Isaac C Ramos, Dan Z Reinstein, Timothy J Archer, Marine Gobbe, Marcella Q Salomão, Bernardo Lopes, Allan Luz, Fernando Faria-Correia, Damien Gatinel, Michael W Belin, Renato Ambrósio Jr
[Year:2016] [Month:January-April] [Volume:5 ] [Number:1] [Pages:51] [Pages No:40-51] [No of Hits : 577]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1120 | FREE

ABSTRACT

To describe a case of very asymmetric ectasia successfully treated by femtosecond laser-assisted intracorneal ring segment implantation, in which the diagnosis of unilateral ectasia in the right eye was based on the clinical findings including history, follow-up, and advanced diagnostic data. The patient’s history was positive for ocular allergy with moderateto- intense eye rubbing only in the right eye. The uncorrected distance visual acuity was 20/63 in the right eye and 20/32 in the left eye. The corrected distance visual acuity (CDVA) was 20/40 in the right eye (-1.75-4.00 × 35°) and 20/16 in the left eye (-0.50-0.25 × 115°). After femtosecond laser-assisted intracorneal ring segment implantation, the right eye improved CDVA to 20/20-1. Concerning ectasia/keratoconus diagnosis, the left eye remained stable over 1 year of follow-up with unremarkable topometric, tomographic, and biomechanical findings. Epithelial thickness mapping by spectral domain optical coherence tomography and very-high-frequency digital ultrasound demonstrated epithelial thickness within normal limits in the left eye. Advanced diagnostic methods along with clinical data enable the distinction from unilateral ectasia cases and subclinical (fruste) keratoconus. Literature review is also performed along with case presentation and discussion.

Keywords: Corneal tomography, Keratoconus, Unilateral ectasia.

How to cite this article: Ramos IC, Reinstein DZ, Archer TJ, Gobbe M, Salomão MQ, Lopes B, Luz A, Faria-Correia F, Gatinel D, Belin MW, Ambrósio R Jr. Unilateral Ectasia characterized by Advanced Diagnostic Tests. Int J Kerat Ect Cor Dis 2016;5(1):40-51.

Source of support: Nil

Conflict of interest: Drs. Ambrósio and Belin are consultants for Oculus (Wetzlar, Germany); Dr. Reinstein is a consultant for Carl Zeiss Meditec (Carl Zeiss Meditec AG, Jena, Germany) and has proprietary interest in the Artemis technology (ArcScan Inc, Morrison, Colorado, USA) through patents administered by the Center for Technology Licensing at Cornell University (CTL), Ithaca, New York, USA. Dr. Gatinel is a consultant for TECHNOLAS Perfect Vision (Munich, Germany). The remaining authors have no proprietary or financial interest in the materials presented herein.

 
6.  Review Article
High-order Aberrations in Keratoconus
Hagar Hefner-Shahar, Nir Erdinest
[Year:2016] [Month:September-December] [Volume:5 ] [Number:3] [Pages:45] [Pages No:128-131] [No of Hits : 562]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1133 | FREE

ABSTRACT

With all the technological advances today and the increasing number of people undergoing refractive surgery, the importance of detecting keratoconus (KC) prior to surgery has become evident. Although by using a topographer we can detect early stage KC, however, by using wavefront analysis technology, we are able to detect KC at an even earlier stage.
Every eye possesses a number of aberrations. However, in a KC patient’s eye, there are approximately five to six times the numbers of high-order aberrations (HOAs) than in a healthy eye. Using this technology to detect and assess the HOAs, it was found that in a KC cornea, it is possible to detect at a very early stage a much higher value of vertical coma aberrations compared with a normal eye. By using this technology, it is possible to study and understand the characteristics of the quality of the image on the retina, thereby understanding its impact on the patient’s visual quality.

Keywords: Aberrations, High-order, Keratoconus, Vertical coma, Wavefront.

How to cite this article: Hefner-Shahar H, Erdinest N. Highorder Aberrations in Keratoconus. Int J Kerat Ect Cor Dis 2016;5(3):128-131.

Source of support: Nil

Conflict of interest: None

 
7.  Case Series
Simultaneous Topography-guided Surface Ablation with Collagen Cross-linking for Keratoconus
Lily Karmona, Tzahi Sela, Oz Franco, Avi Shoshani, Gur Munzer, Igor Kaiserman
[Year:2016] [Month:May-August] [Volume:5 ] [Number:2] [Pages:39] [Pages No:71-76] [No of Hits : 539]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1124 | FREE

ABSTRACT

Purpose: In this article, we present the results of eight eyes of patients who underwent combined same-day partial topographyguided surface ablation followed by accelerated collagen cross-linking (CXL) procedure at Care-Vision Laser Centers to achieve stabilization of corneal ectasia and enhance visual rehabilitation in keratoconus.

Materials and methods: A retrospective nonrandomized review of 8 eyes of 6 patients who underwent the Athens Protocol for progressive keratoconus. Each patient underwent topography-guided ablation followed by CXL procedure.

Follow-up: Follow-up was done on day 1, day 7, and then at 1, 3, 6, and 12 months.

Results: There was a rapid and significant improvement in uncorrected visual acuity and best-corrected visual acuity in 100% eyes, a reduction of keratometric values, and symmetry between vertical hemimeridians. Topographic evaluation showed a marked improvement in irregularity. There were no signs of keratoconic progression noted in any of the eyes on last follow-up. No adverse events were reported in any patient.

Conclusion: Simultaneous surface ablation + CXL seems to be a promising treatment capable of offering patients functional vision and halting progression of the disorder.

Precis: Simultaneous topography-guided custom ablation treatment and photorefractive keratectomy with CXL offers keratoconic patients intolerant to contact lenses both stabilization of the cornea and improved functional vision with spectacles correction.

Keywords: Athens protocol, Keratoconus, Topography-guided surface ablation.

How to cite this article: Karmona L, Sela T, Franco O, Shoshani A, Munzer G, Kaiserman I. Simultaneous Topography-guided Surface Ablation with Collagen Cross-linking for Keratoconus. Int J Kerat Ect Cor Dis 2016;5(2):71-76.

Source of support: Nil

Conflict of interest: None

 
8.  Case Series
Keratoconic Bi-aspheric Contact Lenses
Liat Gantz, Ariela Gordon-Shaag, Arige Gideon-Abousaid, Gad Serero, Philip Fine
[Year:2016] [Month:September-December] [Volume:5 ] [Number:3] [Pages:45] [Pages No:132-138] [No of Hits : 517]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1134 | FREE

ABSTRACT

Aim: This observational clinical case series examined patients with keratoconus (KC) fit with keratoconic bi-aspheric (KBA) lenses to assess visual acuity (VA), wavefront aberrations, physiological fitting, subjective comfort, and manufacturer’s fitting guidelines.

Materials and methods: Seven adult patients (11 eyes, four females, mean age: 34.15 ± 14.12) with nipple cones from the Hadassah Academic College contact lens clinic (Jerusalem, Israel) were fit with KBA lenses by modifying the initial base curve (BC) to obtain an acceptable physiological fit. The uncorrected and corrected distance (D) and near (N) Snellen VA and the ocular wavefront measurements, and responses to a self-administered five-point scale questionnaire were compared after 2 weeks of wear using paired two-tailed t-test or Mann- Whitney U test, as appropriate.

Results: Visual acuity and total root mean square (RMS) improved significantly with the lenses (DVAuncorrected = 0.04 ± 0.02, DVAcorrected = 0.66 ± 0.22, NVAuncorrected = 0.34 ± 0.30, NVAcorrected = 0.95 ± 0.12). Subjects reported an average of 7.0 ± 2.7 hours of wear daily, with good scores in visual stability, satisfaction with VA and quality of vision, improvement of mood and quality of life, and low scores in foreign body sensation, pain, red eye, and itching during wear, and difficulty with lens removal. An average of two BC modifications from the diagnostic lens were necessary (0.16 mm steeper in nine eyes, 0.27 mm flatter in two eyes).

Conclusion: Keratoconic bi-aspheric lenses can provide 7 hours of comfortable wear, significantly improved VA and total RMS aberrations, alongside subjective satisfaction. Base curve modifications can be reduced by fitting a diagnostic lens 0.75 mm steeper than the flattest keratometry reading.

Keywords: Contact lenses, Gas permeable contact lenses, Higher order aberrations, Keratoconus, Visual acuity.

How to cite this article: Gantz L, Gordon-Shaag A, Gideon- Abousaid A, Serero G, Fine P. Keratoconic Bi-aspheric Contact Lenses. Int J Kerat Ect Cor Dis 2016;5(3):132-138.

Source of support: Nil

Conflict of interest: None

 
9.  Original Article
Keratoconic Cone Using its Keratometry, Decentration, and Thickness as Staging Parameters
Kyaw L Tu, Abdo K Tourkmani, Singaram Srinivas
[Year:2016] [Month:September-December] [Volume:5 ] [Number:3] [Pages:45] [Pages No:99-104] [No of Hits : 506]
Full Text PDF | Abstract | DOI : 10.5005/jp-journals-10025-1129 | FREE

ABSTRACT

Aim: To propose a new system of keratoconus staging using a set of parameters describing the keratoconic cone.

Materials and methods: Retrospective case series study of 101 keratoconic eyes of 58 patients was undertaken. They all had complete eye examination including corneal topography (Oculus Pentacam). Kmean, Kmax, higher order aberrations (HOAs) root mean square (HOARMS) value, pachymetry at thinnest point and steepest corneal meridian were obtained from Pentacam. Apex to thinnest pachymetry distance (D) was calculated using trigonometry. Pearson correlation coefficients between Kmax and HOARMS, between D on the one hand and the adjusted angle of steepest meridian, Kmean and Kmax respectively on the other, were calculated.

Results: There is a statistically significant positive correlation between Kmax and HOARMS (p < 0.00001). There is a negative correlation, a “horizontalization,” of the steep meridian with D increase, although it fell short of statistical significance (p = 0.07). D and Kmean (p = 0.003), and D and Kmax (p = 0.005) are significantly negatively correlated.

Conclusion: Kmax correlates with significant changes in HOAs. D correlates with corneal astigmatic meridian change and has a divergent path to Kmean and to Kmax. We propose a new keratometry, decentration, and thinnest pachymetry staging using the parameters Kmax (K), distance from the corneal apex to the thinnest pachymetry point (D), and corneal thickness at its thinnest point (T) to give a better, detailed description of a keratoconic cornea which could lead to improvements in assessment of its severity and treatment outcomes.

Keywords: Decentration, Keratometry, Thickness.

How to cite this article: Tu KL, Tourkmani AK, Srinivas S. Keratoconic Cone using its Keratometry, Decentration and Thickness as Staging Parameters. Int J Kerat Ect Cor Dis 2016;5(3):99-104.

Source of support: Nil

Conflict of interest: None

 
10.  
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 : 8428]
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).

 
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