Search

Purpose: To study the corneal flattening effect of cross-linking (CXL) overtime and to look for a potential association with preoperative topographic variables and the central depth of demarcation line (DDL)., Methods: 201 eyes of 146 patients (mean age of 31.2 ± 7.3 years) with progressive keratoconus who underwent CXL between June 2007 and December 2012 were enrolled in this retrospective study. Follow-up visits were performed at different time intervals for at least 5 years. Preoperative parameters and depth of demarcation line were collected from LaserVision ophthalmology center in Lebanon. Corneal flattening was defined by a change in postoperative Kmax (ΔKmax) greater than 1.00 D., Results: ΔKmax increased from 50.25% to 61.69%, from first to last follow-up visits. The only factor significantly correlated to ΔKmax during all follow-up visits was preoperative maximum keratometry (Kmax) especially when greater than 50.00 D (OR, 1.92; 95% CI, 1.10-3.34). All eyes showed a corneal demarcation line (mean central depth (DDL): 217.11 ± 26.54 μm), with no statistically significant correlation between DDL and ΔKmax., Conclusion: CXL effect on cornea can be cumulative overtime and delayed flattening occurs in some cases. ΔKmax is positively correlated with preoperative Kmax and no association was found between ΔKmax and DDL. Therefore, DDL may not be a valid measure for the efficacy of CXL.

Flap creation weakens the cornea and is a risk factor for keratectasia after laser in situ keratomileusis (LASIK). We describe a new technique to halt the progression of keratectasia by mechanically reintegrating the flap into the residual stroma. Deep stromal vertical puncturing is performed in the 4.0 to 9.0 mm paracentral corneal zone at a depth of 350 to 420 μm. The puncturing is applied in circumferential rows using a 25-gauge needle or a diamond blade, with denser puncturing at the level of the cone. In 5 eyes with worsening post-LASIK keratectasia, improved uncorrected and corrected visual acuities, corneal flattening, and a hyperopic shift were observed. There was no progression of keratectasia on serial topographies. New collagen fibrogenesis was documented by optical coherence tomography. The technique seems to be promising to halt the progression of post-LASIK keratectasia. More clinical data and longer follow-up are needed for validation., (Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Keratoconus is a degenerative disease that affects adolescents and young adults and presents with variable thinning and conical deformation of the corneal apex. The resultant irregular astigmatism can progress to levels that can significantly affect everyday activities and overall quality of life. Therefore, stopping the progression of the disease is an essential part in managing patients with keratoconus. Corneal collagen cross-linking is a minimally invasive procedure that stiffens the anterior corneal stroma by creating strong covalent bonds between collagen fibrils. Over the past decade, many studies have proved its safety and efficacy in halting keratoconus progression in adults. This review of the literature highlights the growing trend towards using this treatment in pediatric keratoconic patients. In children, keratoconus tends to be more severe and fast progression is often encountered requiring closer follow-up intervals. Standard cross-linking shows comparable results in children with a good safety-efficacy profile during follow-up periods of up to three years. Further research is needed to standardize and evaluate transepithelial and accelerated cross-linking protocols as these could be of tremendous help in a population where cooperation and compliance are major issues.

Purpose: To evaluate the safety and clinical outcome of phakic Visian toric implantable collamer lens (ICL) (STAAR Surgical, Monrovia, CA) insertion after corneal collagen cross-linking (CXL) in progressive keratoconus., Methods: A retrospective study examined the results of the two-step CXL and Visian toric ICL implantation in 16 eyes of 10 patients with keratoconus. The two procedures were done at an interval of 6 months. Data were collected preoperatively, at the 6-month follow-up visit after CXL, and at the 6-month follow-up visit after ICL implantation., Results: CXL induced a statistically significant decrease in steep keratometry (50.02 ± 4.07 at baseline to 48.74 ± 4.05 at 6 months after CXL, P = .001) without any significant change in visual acuity or refraction. At 6-month follow-up after ICL implantation, mean K (max) was 50.49 ± 4.07 versus 52.29 ± 4.79 D at baseline (P = .001). Mean uncorrected distance visual acuity improved from 1.67 ± 0.49 to 0.17 ± 0.06 logMAR (P = .001) and mean corrected distance visual acuity improved from 0.15 ± 0.06 to 0.12 ± 0.04 logMAR (P = .023). Mean spherical equivalent decreased from -7.24 ± 3.53 to -0.89 ± 0.76 D (P = .001) and mean cylinder decreased from 2.64 ± 1.28 to 1.16 ± 0.64 D (P = .001). The safety and efficacy indices were 1.08 ± 0.13 and 0.97 ± 0.08, respectively. No intraoperative or postoperative complications occurred., Conclusions: Implantation of the Visian toric ICL following CXL is an effective option for improving visual acuity in patients with keratoconus., (Copyright 2013, SLACK Incorporated.)

Purpose: To assess the effectiveness and safety of 2 types of 6.0 mm intrastromal corneal ring segments (ICRS) in patients with mild to severe keratoconus., Setting: Lebanese American University, Beirut, Lebanon., Design: Retrospective comparative case series., Methods: Eyes had implantation of Intacs SK ICRS (Group 1) or Keraring SI6 ICRS (Group 2). Visual acuity (logMAR), refraction, keratometry, and higher-order aberrations were compared 6 months and 1 year postoperatively., Results: Group 1 comprised 66 eyes and Group 2, 107 eyes. The groups were comparable preoperatively. One-year postoperatively, the mean uncorrected distance visual acuity improved by 0.62 logMAR ± 0.19 (SD) in Group 1 and by 0.67 ± 0.17 logMAR in Group 2 (P=.211). The mean corrected distance visual acuity improved by 0.12 ± 0.11 logMAR and by 0.08 ± 0.13, respectively (P=.301). The spherical equivalent decreased by a mean of 2.80 ± 2.87 D and 2.65 ± 3.00 D, respectively (P=.572). Keratometry (K) flat and K steep decreased by a mean of 1.51 ± 1.57 D and 2.24 ± 1.61 D, respectively, in Group 1 and by 1.10 ± 2.00 D and 1.44 ± 1.64 D, respectively, in Group 2 (P=.667 and P=.184, respectively). Primary coma root mean square decreased by a mean of 1.09 ± 0.66 μm in Group 1 and 0.99 ± 0.72 μm in Group 2 (P=.716)., Conclusion: Both ICRS models significantly improved visual function in patients with keratoconus, with comparable postoperative profiles and no major complications., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned., (Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Objective: Screening for keratoconus and potential risk factors in a medical student population in Lebanon using anterior topography., Population and Methods: We randomly selected 110 medical students doing rotations in the Hôtel-Dieu de France hospital in Lebanon between November 2009 and February 2010. Ninety-two students agreed to participate in the screening protocol, which included a questionnaire and an anterior topography. The topography was performed using the placido disk Tomey(®) Topographic Modeling System TMS-4. The results were interpreted using the analysis programs supplied with the machine and by an experienced ophthalmologist., Results: Ninety-two students participated in the study (83.6%): 49 males (53.2%) and 43 females (46.8%). The mean age was 23.6±1 year. Fifty-eight students were ametropic (63.1%): 44 participants were myopic (47.8%), 40 had astigmatism (43.4%), and six were hyperopic (6.5%). Three students (six eyes) were diagnosed with keratoconus. The prevalence of keratoconus was 3.3%, of which 2.2% were already known cases. The prevalence of forme frustre keratoconus was 1.1%. Eleven students (12.1%) had a family history of keratoconus, only one was diagnosed with the disease. Atopy and eye rubbing were not found significantly related to keratoconus in this population., Conclusion: Keratoconus is a prevalent disease among our population of Lebanese medical students, which confirms the clinical impression that keratoconus is relatively frequent in Lebanon. Further studies need to be conducted on a larger and more representative sample to assess keratoconus prevalence and risk factors in Lebanon., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)