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.

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.

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.

Prevalence of refractive errors and color vision deficiency in a population of industry-workers in Abhar, Iran.

ABSTRACT: Visual impairment due to refractive errors and color vision deficiency (CVD) can affect the visual abilities of workers in workplace. Identifying the prevalence of common visual problems helps us to prevent and treat occupational ocular problems.This study was conducted on 2600 males referring from companies for a routine medical exam to Occupational Medicine Center. In all subjects, visual acuity and refraction were measured. Assessment of color vision was performed by Ishihara color test. In present study, right eyes of subjects were selected to statistical analysis.The mean spherical equivalent was -0.19 ±â€Š1.39 diopter with a range of -11.00 to +10.00 diopter. Whereas 71% of persons were emmetropic, 20% and 9% of them were myopic and hypermetropic, respectively. From a total subjects, 164 of them had CVD with prevalence of color blindness of 6.3%. In comparison with normal subjects, CVD had no significant effect on refractive findings of our subjects (P > .05).Our data present the prevalence of refractive errors and color blindness among Iranian industry-workers. Compared with other studies, our subjects have a lower prevalence of refractive errors, and similar rate of prevalence of color blindness.