Long-term Outcomes of Collagen Crosslinking for Early Keratoconus

Purpose: To evaluate the long-term outcomes of collagen crosslinking in early keratoconus. Methods: Thirty eyes of twenty patients with early keratoconus were enrolled. Uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), objective refraction, subjective refraction, corneal topography and pachymetry were assessed before and 3, 6, 12 months and 9 years after performing collagen crosslinking surgery. Results: The patients’ mean age was 31.2 ± 5.59 years at nine-year follow-up (range, 25–44 years). The means of preoperative UCVA and BSCVA were 0.57 ± 0.34 and 0.15 ± 0.12 logMAR, respectively, and these values remained stable at the final follow-up (P = 0.990 and P = 0.227, respectively). The mean objective spherical equivalent decreased considerably from –6.00 ± 4.05 D preoperatively to –5.22 ± 3.71 D at the final follow-up (P < 0.05). The mean subjective spherical equivalent was –4.25 ± 2.87 D preoperatively and this value was stable at the last follow-up (P = 0.92). No considerable difference was found between the post- and preoperative mean objective cylinder values (P = 0.34). The mean subjective cylinder value changed significantly from –4.05 ± 1.85 D preoperatively to –3.1 ± 1.42 D at the final follow-up (P < 0.05). The mean central corneal thickness was 496.97 ± 45.95 μm preoperatively and this value was stable at nine-year follow-up (P = 0.183). No significant difference was found between the pre- and postoperative mean maximum and mean minimum corneal curvature values (P = 0.429 and P = 0.248, respectively). There were no significant postoperative complications. Conclusion: Corneal crosslinking in early keratoconus seems to be a safe procedure that can effectively stabilize UCVA, BSCVA, subjective SE and CCT, while improving objective spherical equivalent

Preferred Learning Styles among Ophthalmology Residents: An Iranian Sample

Purpose: This study was performed to assess the learning styles of a sample of Iranian residents through Kolb’s and VARK questionnaires. Methods: In this descriptive-analytical study, 45 ophthalmology residents of Mashhad University of Medical Sciences were enrolled. Kolb’s and VARK questionnaires were provided, and residents were oriented and guided on how to complete them. Results: Forty-three out of the forty-five ophthalmology residents completed the questionnaire (95.5% response rate). The preferred learning style among ophthalmology residents was assimilative (51.2%), followed by convergent (37.2%), accommodative (7.7%), and divergent (4.7%), based on Kolb’s questionnaire. According to the results of the VARK questionnaire, most ophthalmology residents were auditory learners (34.9%), followed by multimodal learners (30.2%). In addition, there was no significant relation between genders, stage of residency, and Kolb’s and VARK learning styles (P > 0.05 for all). Conclusion: The most preferred learning styles of ophthalmology residents were assimilative and auditory. Considering the dominant learning styles of learners and incorporating various teaching methods are recommended to enhance the learning among residents

Comparing Subcutaneous Tissue Responses to Freshly Mixed and Set Root Canal Sealers

INTRODUCTION: The purpose of this study was to compare the subcutaneous tissue responses of freshly mixed or set endodontic root canal sealers (i.e. RoekoSeal, AH26, AH Plus) in Wistar Albino rats. MATERIALS AND METHODS: Seventy-two male albino rats weighing 200-250g were used. The animals were randomly divided into six groups of 12 rats each. Root canal sealers were implanted in subcutaneous tissue in both freshly mixed and set conditions. The animals were sacrificed after 7, 14, and, 60 days. After histological preparation and Hematoxylin and Eosin (H&E) staining, the specimens were evaluated for capsule thickness, severity and extent of inflammation, and necrosis. Results were statistically analyzed using Multivariate ANOVA test. RESULTS: Differences between set and freshly mixed root canal sealers were significant (P=0.014), but not significant between test materials and controls, except for capsule thickness and extent of inflammation between control and AH26 (P=0.019 and P=0.006 respectively). The interaction between the type of material and setting condition was significant for capsule thickness and severity of inflammation in AH26 specimens at 14 and 60 days (P=0.001). CONCLUSION: Based on the results of this study assessing the biocompatibility, both set and freshly mixed states can be used. [Iranian Endodontic Journal 2009;4(4):152-7

Association of the Myocilin Gene Polymorphism With Primary Open Angle Glaucoma

Glaucoma is the second cause of irreversible blindness, and the Primary Open Angle Glaucoma (POAG) subtype is the most common type of glaucoma. It has been shown that genetic mutations increase the risk of POAG used for early detection. The aim of the current study was to determine the association between genetic variations of Myocilin (MYOC) gene and susceptibility to POAG in the Iranian population. This case-control study was conducted on patients with POAG, referred to Khatam-al Anbia Eye Hospital, Mashhad, Iran. The control group was selected from healthy patients with a refractive disorder, who had referred to this hospital. After extracting the DNA from the whole blood sample, the Polymerase Chain Reaction-Single-Strand Conformation Polymorphisms (PCR-SSCP) method was used to discriminate variability in sequences in three exons of MYOC gene locus, known as GLC1A. Clinical characteristics of the subjects, comprised of visual acuity, Cup to Disc Ratio (CDR), and Intra-Ocular Pressure (IOP) were statistically compared between the wild and mutant type of the MYOC gene using independent samples t-test, Chi-square, and logistic regression test with SPSS version 15.0 software. P-values of < 0.05 were considered significant. One hundred and forty participants (75.1% males) were studied in two groups of case (n = 70) and control (n = 70). The frequency of mutant alleles in patients and healthy groups was statistically significant (40% versus 11.5%, Odd’s Ratio (OR): 5.1, CI 95% for OR: 2.1 to 12.4, P-value < 0.001). Also, the detected mutation in the case group was significantly higher in exon 1 and 3 (15.7% versus 0%, P-value = 0.001, and 11.5% versus 2.8%, P-value = 0.049, respectively). Based on the result of the current study, it seems that the MYOC gene polymorphisms increased the risk of POAG in the Iranian population

Effect of Cataract Type and Severity on Visual Acuity and Contrast Sensitivity

Purpose: To determine the effect of cataract type and severity in eyes with pure types of age-related lens opacities on visual acuity (VA) and contrast sensitivity in the presence and absence of glare conditions. Methods: Sixty patients with senile cataracts aged 40 years or older with no other ocular pathologies were evaluated for VA and contrast sensitivity with and without glare. Lens opacities were classified according to the Lens Opacities Classification System (LOCS) III. VA was measured using the Snellen chart. Contrast sensitivity was measured with the Vector Vision CSV-1000E chart in the presence and absence of glare by calculating the area under log contrast sensitivity (log CS) function (AULCSF). Results: Cataracts were posterior subcapsular in 26 eyes, cortical in 19 eyes and nuclear in 15 eyes. VA significantly decreased with increasing cataract severity and there was significant loss of contrast sensitivity at all spatial frequencies with increasing cataract severity. AULCSF significantly decreased with increasing cataract severity in the presence and absence of glare conditions. Contrast sensitivity was significantly reduced at high spatial frequency (18 cpd) in cortical cataracts in the presence of glare in day light and at low spatial frequency (3 cpd) in night light. Conclusion: Increased cataract severity is strongly associated with a decrease in both VA and AULCSF. Contrast sensitivity scores may offer additional information over standard VA tests in patients with early age-related cataracts

The effect of intravitreal bevacizumab injection on the corneal endothelial cells

Introduction:Bevacizumab (Avastin), as an effectiveness treatment modality, is currently used in patients with various ocular disease. However the results have been promising, the use of bevacizumab in the treatment of ocular disease is an off-label application. Hence, the aim of this study was to systematically review the effectiveness of intravitreal injection of bevacizumab on various ocular tissues, especially corneal endothelial cells. Methods: The articles related to the effect of application of Avastin in the treatment of ophthalmic diseases and especially its effect on corneal endothelial cells were collected and reviewed. We searched PubMed, Google scholar, and Scopus databases and used Avastin, ocular diseases and corneal endothelial cells as search keywords.Result: Of all 55 articles found in all databases, only 10 were relevant to the purpose of this study, and 45 articles were excluded in several step by step process of article selection according to the inclusion/exclusion criteria. The results revealed that intracameral bevacizumab injection caused no changes in specular microscopy and corneal pachymetry. Moreover, it had no significant toxicity on corneal endothelial cells.Discussion: Effectiveness of bevacizumab as a new modality in the treatment of different ophthalmic diseases have been suggested. Recent data on both human and animal models showed that intravitreal injection of bevacizumab resulted in no significant toxicity on various ocular cells, and it could be considered as a suitable therapeutic approach in clinical use.Conclusion: According to the results of included documents, bevacizumab was not toxic to corneal endothelial cells at various clinically relevant doses