Current focus of stem cell application in retinal repair

The relevance of retinal diseases, both in society's economy and in the quality of people's life who suffer with them, has made stem cell therapy an interesting topic forresearch. Embryonic stem cells(ESCs), induced pluripotent stem cells(i PSCs) and adipose derived mesenchymal stem cells(ADMSCs) are the focus in current endeavors as a source of different retinal cells, such as photoreceptors and retinal pigment epithelial cells. The aim is to apply them for cell replacement as an option for treating retinal diseases which so far are untreatable in their advanced stage. ESCs, despite the great potential for differentiation, have the dangerous risk of teratoma formation as well as ethical issues, which must be resolved before starting a clinical trial. i PSCs, like ESCs, are able to differentiate in to several types of retinal cells. However, the process to get them for personalized cell therapy has a high cost in terms of time and money. Researchers are working to resolve this since i PSCs seem to be a realistic option for treating retinal diseases. ADMSCs have the advantage that the procedures to obtain them are easier. Despite advancements in stem cell application, there are still several challenges that need to be overcome before transferring the research results to clinical application. This paper reviews recent research achievements of the applications of these three types of stem cells as well as clinical trials currently based on them.

Intravitreal dexamethasone implants for diabetic macular edema

AIM： To evaluate the safety and efficacy of a dexamethasone（DEX） intravitreal implant for diabetic macular edema（DME）.METHODS： Totally 113 eyes of 84 patients were divided in three subgroups： naive patients（n=11）, pseudophakic patients（n=72） and phakic patients（n=30）. Inclusive criterion comprised adult diabetic patients with central fovea thickening and impaired visual acuity resulting from DME for whom previous standard treatments showed no improvement in both central macular thickness（CMT） and best corrected visual acuity（BCVA） after at least 3 mo of treatment. Outcome data were obtained from patient visits at baseline and at months 1, 3, 5, 9 and 12 after the first DEX implant injection. At each of these visits, patients underwent measurement of BCVA, a complete eye examination and measurement of CMT and macular volume（MV） carried out with optical coherence tomography（OCT） images. RESULTS： Seventy-three eyes（64.5%） received a single implant, 30（26.5%） received two implants and 10（9%） received three implants. At baseline, average in BCVA, CMT and MV were 43.5±20.8, 462.8±145 and 12.6±2.5 respectively. These values improved significantly at 1 mo（BCVA： 47.2±19.5, CMT： 339.6±120, MV： 11.11±1.4） and 3 mo（BCVA： 53.2±18.1, CMT： 353.8±141, MV： 11.3±1.3）（P≤0.05）. At 5 mo（BCVA： 50.9±19.8, CMT： 425±150, MV： 12.27±2.3）, 9 mo（BCVA： 48.4±17.6, CMT： 445.5±170, MV： 12.5±2.3） and 12 mo（BCVA： 47.7±18.8, CMT： 413.2±149, MV： 12.03±2.5）, improvements in the three parameters were no longer statistically significant and decreased progressively but did not reach baseline values. There were no clinical differences between subgroups. Ocular complications were minimal.CONCLUSION： Patients with DEX implants show maximum efficacy at 3 mo which then declined progressively, but is still better than baseline values at the end of follow-up.

Importance of telemedicine in diabetes care: Relationships between family physicians and ophthalmologists

Diabetic retinopathy(DR) is the worldwide leading cause of legal blindness. In 2010, 1.9% of diabetes mellitus(DM) patients were legally blind and 10.2% had visual impairment. The control of DM parameters(glycemia, arterial tension and lipids) is the gold standard for preventing DR complications, although, unfortunately, DR still appeared in a 25% to 35% of patients. The stages of severe vision threading DR, include proliferative DR(6.96%) and diabetic macular edema(6.81%). This review aims to update our knowledge on DR screening using telemedicine, the different techniques, the problems, and the inclusion of different professionals such as family physicians in care programs.

Neuroprotective therapy for retinal neurodegenerative diseases by stem cell secretome

Retinal neurodegenerative diseases like agerelated macular degeneration,glaucoma,diabetic retinopathy or retinitis pigmentosa are the most frequent causes of incurable low vision and blindness worldwide.It had been estimated that the prevalence of these diseases varies between 1/750 and 1/5000 depending on the region,the level of consanguinity or ethnicity(Na et al.,2017).The functional and structural complexity of the retina makes it susceptible to multiple types of pathogenic damage.

Potential of video games for the promotion of neuroadaptation to multifocal intraocular lenses: a narrative review

Multifocal intraocular lenses(IOLs) are currently usually implanted for the treatment of cataracts because they have been proved to be superior to monofocal IOLs with respect to spectacle independence. In turn, they are associated with a higher prevalence of dysphotopsia symptoms that is one of the most common causes of patient dissatisfaction. Neuroadaptation seems to play a major role in the optimal adaptation to multifocal IOLs. In this context, the development of strategies that facilitate the neuroadaptation process to multifocality might be an effective strategy to reduce patients' dissatisfaction. Video games have been proved to be effective for the improvement of visual acuity and for the promotion of neuroplasticity in elderly subjects and other populations with cortical-related visual impairment. This narrative review highlights the physiological potential of video games as a perceptual strategy to improve visual acuity and promote neuroplasticity in patients using multifocalIOLs, although research is still needed to confirm these benefits in this specific population, with only one comparative study to this date providing evidence of them.

HISTOLOGY OF THE IRIS OF EYES UN-DER CHRONIC LATANOPROST THERAPY

Purpose: To study the histology (light microscopy) of the iris of eyes under chronic therapy with latanoprost Methods: We, prospectively, analyzed 14 iris biopsies of eyes with a photographically documented increase in iris pigmentation, and 8 control eyes. Results: We found that treated irides had melanocytes with increased number of nuclear inclusions,

Clinical Characterization and Frequency of Observation of Hereditary Retinal Diseases： Multicentric Study in Panama in 2012-2013

Retinal dystrophies are genetically determined diseases, implying the loss of function of the retina with a wide phenotypic and genotypic variability. There are very few phenotypic, genotypic and epidemiological data on retinal dystrophies in Latin America. The Objective of this study is to describe the epidemioiogical and clinical characteristics of hereditary retinal and choroidal diseases, in retina practices in Panama. A descriptive study, from 2012 to 2013, was performed in the main retina practices in Panama. All detected patients were given a free appointment to gather their phenotypic characteristics and pedigrees. An incidence of five new cases per year, and an accumulated incidence of 5.35 patients per I0,000 was calculated for the public hospitals. A frequency of 2.7 cases per 1,000 patients was observed in the main retina practices, where 69% had rod-cone dystrophies, 14.3% cone-rod dystrophies, 7.1% Stargardt disease, 4.8% Stargardt-like macular dystrophy and two patients presented other dystrophies. Blindness was the main family antecedent （45.2%）. Retinal pigment was present in 59% and strabismus in 21.4% of the patients. Rod-cone and cone-rod dystrophies had similar geographic distribution and the autosomal recessive inheritance pattern was the most frequently observed. This study gives the first phenotypic data of retinal dystrophies in Panama to orient clinicians for a better diagnosis and phenotyping-genotyping correlation for retinal dystrophies in Central America.

Control of disability glare by means of electrochromic filtering glasses:A pilot study

Purpose:To evaluate the potential clinical usability of a new prototype of ophthalmic blue light filters developed by using electrochromic technology in pseudophakic patients complaining of glare.Methods:A prototype of electrochromic device was developed,with a specific frame that enclosed an electronic driver that allowed personalizing its function for each patient.A pro-spective,observational case series study was performed to test it.Five patients who had un-dergone cataract surgery with clear intraocular lenses and complaining of glare were included in the study.Main outcome measures were the results obtained in the satisfaction questionnaire that was delivered to patients.Then,visual acuity,contrast sensitivity,and reading ability data were evaluated with and without the prototype under diferent lighting conditions and different modes of the prototype after a complete month of use.Lens transmittance was also measured.Results:Visual acuity,contrast sensitivity and reading function did not change significantly with prototype use.The main activity for which the prototype was used was walking.Only one patient found that the dimming level was insuficient.No patients reported variable discomfort when passing tunnels,not sufficiently clear indoors,or put on and remove discomfort.The lenses slightly decreased their transmittance at the end of the study.Conclusion:Glasses based on elect rochromic technology may be acceptable for outdoor/indoor use and for distance-near vision.Future studies with larger samples must be conducted to confirm the clinical usability of these glasses.

伴或不伴增生性玻璃体视网膜病变的视网膜脱离患者细胞因子基因多态性的初步研究

Purpose:Cytokines and other growth factors such as interleukins play an important role in the pathogenesis of proliferative vitreoretinopathy(PVR).Interindividual variations in cytokine production seem to correlate with some cytokine gene polymorphisms.The purpose of this study was to analyse the distribution of these cytokine gene variants in patients with rhegmatogenous retinal detachment(RD)with and without PVR.Methods:Single nucleotide polymorphisms were analysed for five cytokines:tumour necrosis factor-α(TNF-α),transforming growth factor-β 1(TGF-β 1),interferon-γ(IFN-γ),interleukin-6(IL-6)and interleukin-10(IL-10).Patients were divided into two surgically treated groups of RD patients:group RD had 27 patients with RD,and group PVR had 31 patients with RD complicated by PVR.A control group was composed of 46 ethnically matched healthy individuals.Results:The genotype distribution of the TGF-β 1 codon 10 polymorphism differed between PVR and RD patients(p=0.018)and between PVR patients and controls in codon 25(p =0.011).There was a higher frequency of TGF-β 1 codon 10 allele T in PVR patients compared with RD patients(p=0.023).No statistically significant differences between groups were observed for the other polymorphisms examined.Conclusion:An association between the TGF-β 1 genetic profile and the development of PVR was detected in this study.Further studies are necessary to confirm this finding and to establish its clinical relevance.