Mini review: human clinical studies of stem cell therapy in keratoconus.

Treatment of keratoconus is one of the most interesting research fields for researchers in the world. Regenerative medicine based on human stem cells in the treatment of keratoconus has recently received attention. Despite extensive laboratory and animal studies in regenerative medicine of cornea, there are limited clinical studies in keratoconus. These studies showed promising results of stem cell therapy. In initial studies, the transplantation of these cells into stroma was associated with increased vision and improved corneal parameters without side effects. In this article, we tried to review different aspects of keratoconus stem cell therapy, including cell extraction and culture, surgical procedure, effectiveness and safety of this method in human clinical studies.

Vision-related quality of life in patients with retinal vein occlusion.

PURPOSE: This study aims to assess the vision-related quality of life in patients with retinal vein occlusion (RVO) among those referred to Labbafinejad Medical Center and Imam Hossein Hospital between 2019 and 2021. METHODS: This comparative study included 37 eligible patients diagnosed with various types of RVO, with an average age of 61 ± 9. To ensure data validity, we included 74 age- and sex-matched healthy individuals. Only cases with a definitive diagnosis of RVO, confirmed by two retina specialists (ND and RN), were included. We assessed the vision-related quality of life of our participants using the National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ-25). All participants underwent interviews. RESULTS: In our study, we examined the vision-related quality of life in different subgroups of RVO patients. Overall, RVO patients had a significantly lower total VRQoL score compared to healthy individuals (P < 0.001), except in the subscale analysis of specific factors such as ocular pain, color vision, and driving, where no statistically significant difference was observed. A statistically significant difference was found in the comparison of subgroups, indicating lower VRQoL in central retinal vein occlusion (CRVO) patients (P = 0.010). Furthermore, a significant correlation was observed between lower VRQoL and decreased vision (P = 0.009) as well as longer disease duration (P = 0.011). CONCLUSION: Retinal vein occlusion can significantly reduce vision-related quality of life, particularly in more severe cases.

Assessment of the effects of intrastromal injection of adipose-derived stem cells in keratoconus patients.

AIM: To evaluate the efficacy and safety of intrastromal transplantation of adipose-derived stem cells (ASCs) in keratoconus patients. METHODS: This study was conducted on 8 eyes of 8 patients with moderate to severe keratoconus. In the patients, ophthalmic assessments including visual acuity, refraction, slit lamp examination, fundoscopy, corneal topography, and confocal microscopy were performed. Autologous stem cells were used. The isolated stem cells were injected into the corneal stroma by using femtosecond laser. Surgical procedure was similar to intracorneal ring implantation. All patients were re-assessed 1, 3, and 6mo after surgery. RESULTS: The baseline mean visual acuity was 0.48±0.18 and improved to 0.66±0.17 after surgery and final acuity increased by 1.85±0.80 lines (P=0.001). The mean spherical refraction of patients improved 0.34±0.35 D (P=0.039), and the mean cylindrical refraction of patients improved 0.84±0.23 D (P=0.016). The mean flat keratometry decreased 0.78±0.71 D (P=0.017), and the mean steep keratometry decreased 0.59±0.68 D (P=0.023). The mean central corneal thickness of patients improved of 6.29±4.47 µm (P=0.03). The mean keratocyte density at the anterior and middle stroma of cornea increased (P<0.05) but remained stable at the posterior stroma after 6mo. All patients had no complications and their corneas remained transparent. CONCLUSION: Intrastromal transplantation of ASCs has positive effects on vision and refractive parameters in most patients with keratoconus. After six months, visual acuity improved moderately, corneal parameters reduced slightly, and stromal keratocytes density increased. This modality is safe, and patients do not have any complications.

Risk Factors Associated with Keratoconus in an Iranian Population.

Purpose: To determine associated factors for keratoconus (KCN) in the Iranian population. Methods: In this retrospective case-control study, 100 KCN patients and 200 age- and sex-matched individuals, who were either candidates for photorefractive keratectomy or healthy referrals from the Torfeh Eye Hospital, were included as the case and control groups, respectively. KCN patients were all registered at the Iranian National Registry of Keratoconus (KCNRegⓇ). Demographic characteristics, patients' symptoms and their habits, as well as systemic and ocular disorders were documented. Clinical examinations included best corrected visual acuity (BCVA) and refractive error measurements, biomicroscopic examination, and corneal imaging. Results: In this case group, the frequency of mild, moderate, and severe KCN was 38%, 28%, and 34%, respectively. Parental consanguinity (odds ratio [OR] = 1.758, P = 0.029), positive familial history in patients' first degree (OR = 12.533, P < 0.001) and second degree (OR = 7.52, P < 0.001) relatives, vernal keratoconjunctivitis (OR = 7.510, P = 0.003), severe eye rubbing (OR = 10.625, P < 0.001), and systemic diseases including migraine, hypertension, and thyroid disease (OR = 6.828, P = 0.021) were found as associated factors for KCN. Lesser frequency of KCN was observed in patients with Fars ethnicity (OR = 0.583, P = 0.042), with higher levels of wealth indices (OR = 0.31, P < 0.001) and higher levels of education (OR = 0.18, P = 0.024). Conclusion: Severe eye rubbing, vernal keratoconjunctivitis, parental consanguinity and positive familial history of KCN, low socioeconomic status, and low levels of education were significantly associated with KCN in our study population.

Myopic regression after photorefractive keratectomy: a retrospective cohort study.

Background: Myopic regression is a major complication of photorefractive keratectomy (PRK). The rates and causes vary considerably among different studies. This study aimed to investigate myopic regression at six months after myopic PRK. Methods: In this retrospective cohort study, we included all eligible patients with myopia ranging from - 0.75 to - 9 D, aged 18 to 50 years, who underwent PRK by a single surgeon with the availability of preoperative and postoperative data at six months after the initial procedure. All participants underwent comprehensive ophthalmic examinations preoperatively and at six months post-PRK. Overcorrection was planned based on the participant's age range to achieve the desired refractive result after PRK. All patients received the same postoperative antibiotic and steroid eye drops in a similar dosage regimen, and the contact lenses were removed after complete corneal epithelial healing. Based on the spherical equivalent of refraction six months after PRK, eyes without and with myopic regression were allocated into groups 1 and 2, respectively. Results: We included 254 eyes of 132 patients who underwent myopic PRK with a mean (standard deviation) age of 30.12 (7.48) years; 82 (62.12%) were women and 50 (37.88%) were men. The frequency of myopic regression was significantly lower in patients with younger age, lower preoperative cylindrical refraction, and lower ablation depth (all P < 0.05). Overcorrection was more successful in eyes with low myopia than in eyes with high myopia (P < 0.05). The highest frequency of myopic regression occurred in eyes with moderate myopia (25.68%), followed by eyes with high myopia (20.0%) and low myopia (6.54%). Among different age groups, patients aged ≤ 30 years had a lower frequency of myopic regression. The frequency of myopic regression in the different age groups was 5.0% at 18 - 20 years, 7.46% at 26 - 30 years, 12.28% at 21 - 25 years, 21.31% at 31 - 35 years, and 26.53% at 36 - 50 years. Conclusions: Overcorrection was more successful in eyes with low myopia than in eyes with high myopia. The success rate was higher in younger patients with lower astigmatism and ablation depths. Myopic regression was most frequent in eyes with moderate myopia, followed by those with high and low myopia. Further studies should replicate our findings over a longer follow-up period with a larger sample size before generalization is warranted.

Long-Term Outcome of Photobiomodulation for Diabetic Macular Edema: A Case Report.

Background: Macular edema is the major cause of decreased vision in patients with diabetes. Antioxidative and anti-inflammatory effects of photobiomodulation (PBM) have been reported with near-infrared irradiation. Objective: In this study, the efficacy and safety of PBM with near-infrared radiation in a patient with diabetic macular edema were assessed. Methods: We present the case of a 60-year-old man with diabetic macular edema responding to 670 nm light PBM alone. Results: After PBM, his vision improved and macular edema resolved on optical coherence tomography (OCT) findings without adverse events. In 16 months follow-up, visual acuity remained stable and OCT showed no evidence of recurrence of edema. Conclusions: Six hundred seventy nanometers light PBM can be potentially considered as a therapeutic method in diabetic patients with macular edema. Also, it provides a noninvasive and nonexpensive treatment in home.

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

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.

Successful Surgical Correction of Astigmatism using Customized Ablation Photorefractive Keratectomy.

The aim of this study was to determine the change in the degree of astigmatism in patients treated with customized ablation photorefractive keratectomy (PRK). This is a cross-sectional study that involved 92 otherwise healthy subjects with regular and irregular astigmatism ≥ 1.25 D (mean age: 39.09 ± 7.72 years; range: 20-59 years). All study subjects were treated with customized ablation PRK using a Technolas 217p Excimer Laser System. Before and 6 months after the surgery, a refraction assessment was conducted for each subject, and the effectiveness of the surgery for correcting astigmatism was evaluated. There was a significant change in astigmatism based on the results of an automated refraction exam of -1.67 ± 1.03 D (P < 0.001), from -2.51 ± 1.45 D preoperatively to -0.87 ± 0.94 D postoperatively. There was also a significant change in subjective refraction of -2.00 ± 1.25 D (P < 0.001), from -2.46 ± 1.52 D preoperatively to -0.46 ± 0.97 D postoperatively. Therefore, our results show that customized ablation PRK is effective for correcting astigmatism ≥ 1.25 D (P < 0.001).

Scientometric analysis and mapping of 20 years of glaucoma research.

AIM: To provide a scientometric analysis in the field of glaucoma. METHODS: A bibliometric method was used to obtain a view of the scientific production in field of glaucoma by data extracted from the Institute for Scientific Information (ISI) from 1993 to 2013. Specific parameters were retrieved from the ISI. Articles about glaucoma were analyzed regarding the topics' structure, history, and document relationships using HistCite software. Also, the trends in the most influential publications and authors were analyzed. RESULTS: The number of articles was constantly increasing, and most highly cited articles addressed clinical and epidemiologic topics in this field. During the past three years, there has been a trend towards genomic research studies and also more molecular translational research. CONCLUSION: This was the first scientometric report on glaucoma, analyzing the characteristics of papers and the trends in scientific production. A constant increase was observed in the number of papers, while the subject of papers had a shift in the past three years towards genomic research studies.

Scientometric Analysis and Mapping of Scientific Articles on Diabetic Retinopathy.

Diabetic retinopathy (DR) is the major cause of blindness among the working-age population globally. No systematic research has been previously performed to analyze the research published on DR, despite the need for it. This study aimed to analyze the scientific production on DR to draw overall roadmap of future research strategic planning in this field. A bibliometric method was used to obtain a view on the scientific production about DR by the data extracted from the Institute for Scientific Information (ISI). Articles about DR published in 1993-2013 were analyzed to obtain a view of the topic's structure, history, and to document relationships. The trends in the most influential publications and authors were analyzed. Most highly cited articles addressed epidemiologic and translational research topics in this field. During the past 3 years, there has been a trend toward biomarker discovery and more molecular translational research. Areas such as gene therapy and micro-RNAs are also among the recent hot topics. Through analyzing the characteristics of papers and the trends in scientific production, we performed the first scientometric report on DR. Most influential articles have addressed epidemiology and translational research subjects in this field, which reflects that globally, the earlier diagnosis and treatment of this devastating disease still has the highest global priority.

Age-Related Macular Degeneration: A Scientometric Analysis.

Age-related macular degeneration (ARMD) is a major cause of central blindness among working aged adults across the world. Systematic research planning on any subject, including ARMD is in need of solid data regarding previous efforts in this field and to identify the gaps in the research. This study aimed to elucidate the most important trends, directions, and gap in this subject. The data extracted from the Institute for Scientific Information were used to perform a bibliometric analysis of the scientific productions (1993-2013) about ARMD. Specific parameters related to ARMD were analyzed to obtain a view of the topic's structure, history, and document relationships. Additionally, the trends and authors in the most influential publications were analyzed. The number of articles in this field was found constantly increasing. Most highly cited articles addressed genetic epidemiology and clinical research topics in this field. During the past 3 years, there has been a trend toward biomarker research. Through performing the first scientometric survey on ARMD research, we analyzed the characteristics of papers and the trends in scientific production. We also identified some of the critical gaps in the current research efforts that would help in large-scale research strategic planning.