Mechanisms of Optical Regression Following Corneal Laser Refractive Surgery: Epithelial and Stromal Responses

Majid MOSHIRFAR, Jordan D. DESAUTELS, Brian D. WALKER, Michael S. MURRI, Orry C. BIRDSONG, Phillip C Hoopes, Sr

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 1-9

Laser vision correction is a safe and effective method of reducing spectacle dependence. Photorefractive Keratectomy (PRK), Laser In Situ Keratomileusis (LASIK), and Small-Incision Lenticule Extraction (SMILE) can accurately correct myopia, hyperopia, and astigmatism. Although these procedures are nearing optimization in terms of their ability to produce a desired refractive target, the long term cellular responses of the cornea to these procedures can cause patients to regress from the their ideal postoperative refraction. In many cases, refractive regression requires follow up enhancement surgeries, presenting additional risks to patients. Although some risk factors underlying refractive regression have been identified, the exact mechanisms have not been elucidated. It is clear that cellular proliferation events are important mediators of optical regression.  This review focused specifically on cellular changes to the corneal epithelium and stroma, which may influence postoperative visual regression following LASIK, PRK, and SMILE procedures.

The Correlation between Changes in Biochemical Parameters and Central Macular Thickness in Patients with Non-Proliferative Diabetic Retinopathy


Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 10-16

This study aimed at evaluating the correlation between changes in Hemoglobin A1c (HbA1c) and fasting serum lipids, and Central Macular Thickness (CMT) in patients with Non-Proliferative Diabetic Retinopathy (NPDR). In the current research, both eyes of 68 patients with mild or moderate NPDR, without clinically significant macular edema, were studied. Levels of fasting serum lipids, HbAlc, and CMT were measured during the first visit and at the end of the follow-up period (3 months). For statistical analysis, CMTs of each eye were studied and the correlation of changes was investigated. Additionally, the direction of changes in CMT for each eye was determined, and whether the changes in both eyes were symmetrical was investigated. Out of 68 patients, 24 were male and 44 were female. The mean CMT of all eyes was 290.05 ± 48.90 µm during the first visit and 286.80 ± 37.57 µm on the 3rd month follow-up. The mean HbAlc was 8.71 ± 1.82% at first visit to the hospital and the mean HbAlc was 8.39 ± 1.65% at the final visit. Although the changes in HbA1c and CMT during the follow-up period were statistically insignificant, the correlation of these 2 values was statistically significant (p=0.01). However, amongst l3 patients, the CMTs were asymmetrically changed in each eye during the follow-up period. To the best of the author’s knowledge, this was the first study, which indicated a significant correlation in changes of CMT and HbA1c, even amongst patients with low-grade diabetic retinopathy. Demonstration of asymmetric changes in CMT of each treatment-naive eye of the same patient, during changes in systemic conditions, was another important finding of this study.

Consanguineous Marriage as a Risk Factor for Developing Keratoconus


Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 17-21

Heredity plays an important role in keratoconus (KC). Consanguineous marriage (CM) can affect the transmission of recessively inherited conditions. We aimed to investigate the role of consanguineous marriage in the development of KC. This study included two groups: the first group comprised 415 patients who underwent surgery for KC for the first time at Khalili University Hospital (Shiraz, Iran), between 2010 and 2014; the second group comprised 415 healthy individuals who served as age- and sex-matched controls for the patient group. All study subjects were from the Fars province in Iran. CM type was evaluated by a standard checklist in both groups. The mean inbreeding coefficient (α) was evaluated and compared between the two groups. The percentage of parental first-cousin marriages was 35.4% in the patient group and 18.3% in the control group. The mean inbreeding coefficient (α) was 0.0291 in the patient group and 0.0135 in the control group. Patients with KC had a significantly higher mean inbreeding coefficient (α) than controls (T = 8, df = 828, P < 0.001). Our study suggests that CM can play a role in the pathogenesis of KC. As this disease is among the most frequent ocular disorders in our country, CM should be considered by health care systems within their screening programs.

Striped Circle Visual Acuity Chart; A Novel Visual Acuity Chart Based on the Landolt-C Chart


Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 22-24

Measurement of Visual Acuity (VA) has been used for eye examinations under various clinical conditions. In addition, because of changes in VA with a range of eye diseases, its measurement is used to screen, diagnose, and evaluate response to treatment in numerous eye diseases and predict the patient's visual function. VA and the likelihood of astigmatism could be evaluated simultaneously using a newly designed Stripped Circle (SC) VA chart. This chart has been  developed based on the standard VA measurement scale chart, and the Landolt-C (LC) VA chart and all the standards for a VA chart design were implemented during its development. However, to publicize the clinical application of this VA measurement chart, further studies are required to evaluate its sensitivity, specificity, and repeatability compared with a similar standard VA chart.

The Association between TGF-β1 G915C (Arg25Pro) Polymorphism and the Development of Primary Open Angle Glaucoma: A Case-Control Study


Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 25-31

The purpose of the current study was to identify the potential association between Single Nucleotide Polymorphism (SNP) TGFβ1 +915 (C or G) in codon 25 and Primary Open Angle Glaucoma (POAG). Overall, 88 cases with POAG and a control group of 52 healthy individuals were recruited from the First Ophthalmology Department of Athens University. DNA was isolated from whole blood samples and genotype frequencies for the polymorphism rs1800471 (G915C, Arg25Pro) of the TGF-β1 gene were assessed. Genotype distribution frequencies for the polymorphism rs1800471 (G915C, Arg25Pro) of the TGF-β1 gene were not statistically different between patients with POAG and control subjects. The present study failed to determine any significant genotypic association with POAG, despite the fact that the presence of the C allele was scarcely increased in the POAG when compared with the control group.

Comparison of Visual, Refractive and Aberration Measurements of INTACS versus Tricyclic ICL Lens Implantation; A Four-year Follow-up


Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 32-39

This study was performed to evaluate the visual, refractive, and aberration measurement results of 2 implants, including Intacs Intracorneal Ring Segments (ICRS) and phakic Toric Implantable Collamer Lens (TICL), in patients with moderate Keratoconus (KCN). In this retrospective cross-sectional study, 30 patients with KCN with a mean age of 29.83 years were included in 2 groups, including the Intacs Intracorneal Ring Segments (ICRS) group and the phakic Toric Implantable Collamer Lens (TICL) group. Preoperative data as well as 6-month, 1-, 2-, 3- and 4-year follow-up data after the operation were collected and analyzed with the SPSS software (ver. 23.0, SPSS, Inc., Chicago, IL), using the paired t-test, independent t-test, repeated measures Analysis of Variance (ANOVA), and one-way ANOVA. This study included 30 patients with KCN with a mean age of 29.83 years and range of 25 to 35 years, including 17 males with a mean age of 30.11 years and 13 female with a mean age of 29.25 years. Except for preoperative Uncorrected Distance Visual Acuity (UCDVA), Spherical Equivalent (SE) and astigmatism, there was a significant difference between the 2 groups regarding other variables. The TICL group had a significantly better UCDVA and Best Corrected Distance Visual Acuity (BCDVA) in all post-operative follow-ups, and SE and astigmatism values were significantly lower in all post-operative follow-ups when compared with the ICRS group. There was a significant reduction in corneal and total coma as well as internal trefoil aberrations (P<0.01, P<0.01, and P=0.014, respectively) in the ICRS group, and TICL led to a significant reduction in internal trefoil aberration with P<0.03. Comparison of the 2 groups revealed a significant difference in corneal spherical (P<0.01) and total coma (P=0.02) aberrations and no significant differences in other HOA. Both ICRS and TICL are useful in patients with moderate KCN. However, TICL appears to have more stable and predictable vision results. 

Knowledge and Awareness of Glaucoma in Subjects with Glaucoma and their Normal First-Degree Relatives

Ali Riza Cenk CELEBI

Medical hypothesis discovery and innovation in ophthalmology, Vol. 7 No. 1 (2018), 11 March 2018 , Page 40-47

The objective of this study was to assess knowledge and awareness of glaucoma in subjects with glaucoma and their normal first-degree relatives. Awareness and knowledge of glaucoma were compared between each patient and his/her relative. We designed a questionnaire containing a set of brief and structured questions to gather information regarding the participants’ demographics and knowledge and awareness of glaucoma. There were two groups in this study. The first group (“glaucoma†group) comprised patients diagnosed with glaucoma, while the second group (“relatives†group) consisted of the first-degree relatives of the patients. Ninety-one participants aged over 40 years (mean, 48.5 years) filled the questionnaire. Thirty-four participants belonged to the glaucoma group, while the remaining were first-degree relatives of the patients. According to the responses obtained, 26 (76%) participants in the glaucoma group and 47 (82%) participants in the relatives group had heard of the term “glaucoma.†There were no statistically significant differences related to age or gender in glaucoma awareness. Glaucoma awareness was positively associated with education level in both groups (p < 0.0001). The definition of “glaucoma†in the glaucoma group and the relatives group was known to 20 (58.8%) and 17 (29.8%) participants, respectively, and the difference was statistically significant (p < 0.0001). The adjusted odds ratios for awareness and knowledge of glaucoma were 75.2 (95% confidence interval [CI], 11.80 to 366.65) and 148.7 (95% CI, 14.07 to 1646.52), respectively, for individuals with a university graduate level of education. In our study, education level was the only demographic indicator that was a predictor of knowledge and awareness of glaucoma. While more scientific evidence is obtained, community education with focus on the promotion of knowledge and awareness of glaucoma would be a practical public health strategy, especially for individuals aged more than 40 years with a family history of glaucoma.