Belin MW, Meyer JJ, Duncan JK, 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.

To evaluate safety, efficacy, and stability of cross-linking (CLX) procedure as a method for keratoconus treatment in the I and II stage of disease.

Twenty eyes of 15 patients (13 males, 2 females, average age 31 years) with keratoconus I stage (13 eyes) and II stage (2 eyes) (by Krumeich classi­fication) were treated by CLX procedure, using riboflavin Medio Cross for standard CLX); riboflavin Medio Cross TE for transepithelial CLX was used to treat keratectasia after previous keratorefractive surgery; in all the cases UV CBM X linker (Vega, CSO) was used. The study included evaluation of uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA) pre- and postoperative, pachymetry (central cornea thickness) (Visante OCT, Zeiss) pre- and postoperative, total astigmatism pre- and postoperative, using keratotopography (Atlas, Zeiss). Diagnosis and analysis have been performed at the International Center for Ophthalmology in Moscow, Russian ­Federation, since 2012 to 2014 years. Follow-up period was from 1 to 24 months.

Average UCVA preoperative was 0.4 (Decimal), and average BCVA was 0.64. Average UCVA postoperative was 0.49; average BCVA was 0.66. Total astigmatism preoperative was 2.81 D; total astigmatism postoperative 2.80 D. Central cornea thickness (CCT) preoperative 454 mkm; CCT post­operative 447 mkm.

Cross-linking indicated safety, stability, and efficacy for treatment of I and II stage keratoconus at the end of follow-up period. Cross-linking is not effective in the treatment of II and III stage of disease. Further study is required.

Dementiev D, Sysoeva M, Shipunova A. Two Years’ Experience in Keratoconus Treatment using Collagen Cross-linking. Int J Kerat Ect Cor Dis 2017;6(1):11-13.

The aim of this study is the development and evaluation of clinical significance methodology for determining mech­anical stress (MS) and elasticity of the cornea comparable to its topographic settings.

Combining the data of optical pachymeter, keratotopography, and pneumotonometry through our special software allows us to get Lokolink MS distribution in the cornea in the form of maps, which we propose to call keratotensotopogram (KTT).

Normal KTT has the form of concentric, uniform, and symmetrical zones. In keratoconus (KC), the corneal center is more tense than peripheral part of cornea. The focus zone of KC may coincide with the region of maximum MS or may be out of this area. In the process of vacuum-compression test, the reaction of profile of the cornea was markedly different in patients with healthy corneas and in patients with KC. In all cases of healthy cornea, the curvature increased in the center. In KC, the cornea became more flat in the center under high intraocular pressure (in 100% of cases).

The KTT ineyes with the cornea without pathology differs from KTT in the different cases of KC. The KTT can be used for the diagnosis and prediction of cornea's state to perform the plan of UV irradiation areas for corneal collagen cross-linking.

Anisimov SI, Anisimova SY, Mistryukov AS, Anisimova NS. Technology of the Local Cross-linking (Part 1): Keratotensotopography and Vacuum-compression Topographic Test—New Diagnostic Possibilities for Studying the Local Biomechanical Properties of Cornea. Int J Kerat Ect Cor Dis 2017;6(1):14-16.

Keratoconus (KC) is a progressive, non-inflammatory bilateral but (usually asymmetrical) ecstatic corneal disease, characterized by paraxial stromal thinning and weakening that leads to corneal surface distortion. The reported incidence and prevalence of KC varies widely depending upon the geographic location, diagnostic criteria used and the cohort of patients selected.

To estimate the incidence and indices of KC in patients seeking refractive procedures in Beni Sueif governorate at a span period of one year from March 2013 to March 2014. To describe and analyze the characteristics of the KC population under study.

This study as designed as a prospective surveillance study. All clinical records in the computerized database from pentacam with the clinical diagnosis of KC and / or suspected were included and statistically analyzed.

Data from 2116 cases with the average 28.8 ± 6.5 years old were analyzed over the span of 1 year starting from March 2013 to March 2014. Based on topographic images of the pentacam 36 eyes were diagnosed as KC. The incidence of KC was 1.7% ( 95% confidence interval, 0.55-1.45). In keratoconic patients, the mean age was 28.1 years, the mean K1 and K2 were 45.18±3.44 D and 49.49 ± 4.28 D respectively. The mean minimal pachymetry value was 463± 6.51um, the mean index of surface variance (ISV) was 61± 32, the mean index of vertical asymmetry (IVA) was 0.63±0.38, the mean keratoconus indices (KI) was 1.08±0.14.

This study provides the first population–based estimate of the incidence of keratoconus in Beni suef governorate in the upper Egypt. According to this study incidence rate of KC is comparable to the rate among the Caucasian people in middle Asia e.g. Iran while incidence rate is much higher among Malaysia and Kingdom of Saudi Arabia citizens.

El Sayed MOAK, Ali NH. Incidence and Indices of Keratoconus in Patients presenting for LASIK in Egypt. Int J Kerat Ect Cor Dis 2017;6(1):17-22.

To prospectively review current understanding and future trends of screening for keratectasia risk prior refractive laser vision correction (LVC).

Progressive keratectasia is an uncommon but severe complication of LVC. Preoperative ectatic corneal disease is the most important risk factor. Screening for subclinical ectasia relies on proper interpretation of advanced diagnostic technologies, including front surface corneal topography, three-dimensional tomography, and biomechanical assessments.

Studies involving eyes with normal and stable corneas, compared to eyes with frank ectatic diseases and to eyes with normal topography from patients with very asymmetric ectasia, allow for developing advanced methods and testing its sensitivity. However, the ideal study populations for testing the sensitivity and specificity of ectasia risk assessments are respectively the preoperative of cases that developed ectasia and the ones with stable outcomes after LVC. Young age and low thickness are surrogates of corneal biomechanics, which may be replaced as risk factors by direct measurements. Keratectasia may also occur due to the surgical impact on corneal structure or due to significant trauma postoperatively. Percentage tissue altered higher than 40% is a more sensitive para­meter than a fixed value for minimal residual stromal bed of 250 µm. However, the biomechanical impact from surgery is related to the region and number of lamellae that are severed, so that flap thickness and geometry should play a more relevant role, which is in agreement with finite element simulations. Arti­ficial intelligence methods allow for combining parameters, which significantly enhance the accuracy for detecting ectasia risk.

An enhanced screening approach for preventing keratectasia should consider both preoperative patient-related data and procedure-related parameters to individually characterize ectasia susceptibility or predisposition.

Keratectasia is an uncommon, however, severe complication of LVC. Although prevention is the best strategy, an individualized enhanced ectasia screening approach for ectasia risk assessment prior to LVC procedures should integrate patient-related (individual ectasia susceptibility) and procedure-related parameters (biomechanical impact).

Ambrósio Jr R, Belin MW. Enhanced Screening for Ectasia Risk prior to Laser Vision Correction. Int J Kerat Ect Cor Dis 2017;6(1):23-33.

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.

Abbas S, Barbara R, Barbara A. Water Soluble Tetrazolium Salt-11 as an Alternative to Riboflavin for Corneal Collagen Cross-linking for the Treatment of Keratoconus. Int J Kerat Ect Cor Dis 2017;6(1):42-44.