Attitudes and knowledge of myopia management by Spanish optometrists.

PURPOSE: To investigate the knowledge, training and clinical practice of Spanish optometrists about preventing and controlling myopia progression. METHODS: A web-based questionnaire was distributed to Spanish optometrists through social networks, optometric professional bodies and one of the major Spanish optometrists' associations to assess practitioner perception, understanding, and self-reported clinical practice behavior related to myopia diagnosis and management. RESULTS: A total of 534 optometrists with a mean age of 40.8 ± 10.3 years completed the survey. Most respondents have been practicing optometry for more than 20 years (89.8%), report having actively treated childhood myopia (82.4%), and are very concerned about the increasing frequency of pediatric myopia in their daily practice (85.3%). Almost all of the respondents (97.3%) agreed that the efficacy of treatment is related to the age at which it is prescribed, and more than half (53.6%) considered a progression higher than - 0.50 and up to - 1.00D as the minimum necessary to consider a myopia management option. Respondents who reported actively managing childhood myopia considered orthokeratology, atropine and soft-defocus contact lenses the most effective myopia control interventions. However, the most frequently prescribed form of myopia correction by Spanish optometrists was single-vision spectacles, followed by orthokeratology and soft-defocus contact lenses. CONCLUSIONS: Spanish optometrists are very active in the management of myopia, especially by fitting orthokeratology lenses or dual-focus soft contact lenses for myopia control, but there is still potential for improvement in the methodology they follow for both the diagnosis and management of myopia.

Computer vision syndrome-related symptoms in presbyopic computer workers.

PURPOSE: To evaluate the prevalence of computer vision syndrome (CVS)-related symptoms in a presbyopic population using the computer as the main work tool, as well as the relationship of CVS with the electronic device use habits and the ergonomic factors. METHODS: A sample of 198 presbyopic participants (aged 45-65 years) who regularly work with a computer completed a customised questionnaire divided into: general demographics, optical correction commonly used and for work, habits of electronic devices use, ergonomic conditions during the working hours and CVS-related symptoms during work performance. A total of 10 CVS-related symptoms were questioned indicating the severity with which they occurred (0-4) and the median total symptom score (MTSS) was calculated as the sum of the symptoms. RESULTS: The MTSS in this presbyopic population is 7 ± 5 symptoms. The most common symptoms reported by participants are dry eyes, tired eyes and difficulties in refocusing. MTSS is higher in women (p < 0.05), in laptop computer users (p < 0.05) and in teleworkers compared to office workers (p < 0.05). Regarding ergonomic conditions, MTSS is higher in participants who do not take breaks while working (p < 0.05), who have an inadequately lighting in the workspace (p < 0.05) and in the participants reporting neck (p < 0.01) or back pain (p < 0.001). CONCLUSION: There is a relationship between CVS-related symptoms, the use of electronic devices and the ergonomic factors, which indicates the importance of adapting workplaces, especially for home-based teleworkers, and following basic visual ergonomics rules.

An in vivo model of focal light emitting diode-induced cone photoreceptor phototoxicity in adult pigmented mice: Protection with bFGF.

PURPOSE: To develop a model of focal injury by blue light-emitting diode (LED)-induced phototoxicity (LIP) in pigmented mouse retinas and to study the effects on cone, Iba-1+ cells and retinal pigment epithelium (RPE) cell populations after administration of basic fibroblast growth factor (bFGF) and minocycline, alone or combined. METHODS: In anesthetized dark-adapted adult female pigmented C57BL/6 mice, left pupils were dilated and the eye exposed to LIP (500 lux, 45 s). The retina was monitored longitudinally in vivo with SD-OCT for 7 days (d). Ex vivo, the effects of LIP and its protection with bFGF (0.5 µg) administered alone or combined with minocycline (45 mg/kg) were studied in immunolabeled arrestin-cone outer segments (a+OS) and quantified within a predetermined fixed-size circular area (PCA) centered on the lesion in flattened retinas at 1, 3, 5 or 7d. Moreover, Iba-1+ cells and RPE cell morphology were analysed with Iba-1 and ZO-1 antibodies, respectively. RESULTS: LIP caused a focal lesion within the superior-temporal retina with retinal thinning, particularly the outer retinal layers (116.5 ± 2.9 µm to 36.8 ± 6.3 µm at 7d), and with progressive diminution of a+OS within the PCA reaching minimum values at 7d (6218 ± 342 to 3966 ± 311). Administration of bFGF alone (4519 ± 320) or in combination with minocycline (4882 ± 446) had a significant effect on a+OS survival at 7d and Iba-1+ cell activation was attenuated in the groups treated with minocycline. In parallel, the RPE cell integrity was progressively altered after LIP and administration of neuroprotective components had no restorative effect at 7d. CONCLUSIONS: LIP resulted in progressive outer retinal damage affecting the OS cone population and RPE. Administration of bFGF increased a+OS survival but did not prevent RPE deterioration.

Systemic treatment with 7,8-Dihydroxiflavone activates TtkB and affords protection of two different retinal ganglion cell populations against axotomy in adult rats.

PURPOSE: To analyze responses of different RGC populations to left intraorbital optic nerve transection (IONT) and intraperitoneal (i.p.) treatment with 7,8-Dihydroxyflavone (DHF), a potent selective TrkB agonist. METHODS: Adult albino Sprague-Dawley rats received, following IONT, daily i.p. injections of vehicle (1%DMSO in 0.9%NaCl) or DHF. Group-1 (n = 58) assessed at 7days (d) the optimal DHF amount (1-25 mg/kg). Group-2, using freshly dissected naïve or treated retinas (n = 28), investigated if DHF treatment was associated with TrkB activation using Western-blotting at 1, 3 or 7d. Group-3 (n = 98) explored persistence of protection and was analyzed at survival intervals from 7 to 60d after IONT. Groups 2-3 received daily i.p. vehicle or DHF (5 mg/kg). Retinal wholemounts were immunolabelled for Brn3a and melanopsin to identify Brn3a+RGCs and m+RGCs, respectively. RESULTS: Optimal neuroprotection was achieved with 5 mg/kg DHF and resulted in TrkB phosphorylation. The percentage of surviving Brn3a+RGCs in vehicle treated rats was 60, 28, 18, 13, 12 or 8% of the original value at 7, 10, 14, 21, 30 or 60d, respectively, while in DHF treated retinas was 94, 70, 64, 17, 10 or 9% at the same time intervals. The percentages of m+RGCs diminished by 7d-13%, and recovered by 14d-38% in vehicle-treated and to 48% in DHF-treated retinas, without further variations. CONCLUSIONS: DHF neuroprotects Brn3a + RGCs and m + RGCs; its protective effects for Brn3a+RGCs are maximal at 7 days but still significant at 21d, whereas for m+RGCs neuroprotection was significant at 14d and permanent.

Computer Vision Syndrome in the Spanish Population during the COVID-19 Lockdown.

SIGNIFICANCE: After 6 to 8 weeks of mandatory lockdown due to coronavirus disease 2019 (COVID-19) in Spain, the encouraged change in daily habits resulted in a significant increase in electronic device use. Computer vision syndrome-related symptoms were reported more often in participants who used electronic device for more time and spent less time outdoors. PURPOSE: The main purpose of this study was to evaluate computer vision syndrome-related eye symptoms due to the use of electronic devices during COVID-19 lockdown decreed in Spain in 2020. METHODS: After 6 to 8 weeks of strict lockdown, a total of 730 participants (18 to 73 years old) filled in a customized questionnaire divided into three sections: (1) general demographics, (2) usage habits of electronic devices during this period, and (3) computer vision syndrome-related ocular and visual symptoms associated with their use and with ergonomic practices. RESULTS: The daily duration of use of electronic devices increased an average of 3.1 ± 2.2 h/d during the lockdown, with computer use increasing the most. The main symptoms reported by the participants were headache (36.7%), dry eye (31.1%), irritation (24.1%), blurred vision (21.2%), and ocular pain (14.9%). There was a significant relationship between computer vision syndrome-related symptoms and age (greater in participants between 18 and 30 years old than in those older than 45 years, P < .001), primary activity (greater in studying from home and remote working, P < .001), and extended periods of electronic device use (greater when used more than 10 h/d, P = .05). Symptoms were also associated with time spent outdoors (greater in participants with <1 h/d, P = .02). CONCLUSIONS: The lockdown due to COVID-19 showed an increase in the electronic device use. Participants who spent more time with electronic devices and less time outdoors reported more computer vision syndrome-related eye symptoms.

Glial Cell Activation and Oxidative Stress in Retinal Degeneration Induced by ß-Alanine Caused Taurine Depletion and Light Exposure.

We investigate glial cell activation and oxidative stress induced by taurine deficiency secondary to ß-alanine administration and light exposure. Two months old Sprague-Dawley rats were divided into a control group and three experimental groups that were treated with 3% ß-alanine in drinking water (taurine depleted) for two months, light exposed or both. Retinal and external thickness were measured in vivo at baseline and pre-processing with Spectral-Domain Optical Coherence Tomography (SD-OCT). Retinal cryostat cross sections were immunodetected with antibodies against various antigens to investigate microglial and macroglial cell reaction, photoreceptor outer segments, synaptic connections and oxidative stress. Taurine depletion caused a decrease in retinal thickness, shortening of photoreceptor outer segments, microglial cell activation, oxidative stress in the outer and inner nuclear layers and the ganglion cell layer and synaptic loss. These events were also observed in light exposed animals, which in addition showed photoreceptor death and macroglial cell reactivity. Light exposure under taurine depletion further increased glial cell reaction and oxidative stress. Finally, the retinal pigment epithelial cells were Fluorogold labeled and whole mounted, and we document that taurine depletion impairs their phagocytic capacity. We conclude that taurine depletion causes cell damage to various retinal layers including retinal pigment epithelial cells, photoreceptors and retinal ganglion cells, and increases the susceptibility of the photoreceptor outer segments to light damage. Thus, beta-alanine supplements should be used with caution.

Short- and Long-Term Study of the Impact of Focal Blue Light-Emitting Diode-Induced Phototoxicity in Adult Albino Rats.

BACKGROUND: In adult rats we study the short- and long-term effects of focal blue light-emitting diode (LED)-induced phototoxicity (LIP) on retinal thickness and Iba-1+ activation. METHODS: The left eyes of previously dark-adapted Sprague Dawley (SD) rats were photoexposed to a blue LED (20 s, 200 lux). In vivo longitudinal monitoring of retinal thickness, fundus images, and optical retinal sections was performed from 1 to 30 days (d) after LIP with SD-OCT. Ex vivo, we analysed the population of S-cone and Iba-1+ cells within a predetermined fixed-size circular area (PCA) centred on the lesion. RESULTS: LIP resulted in a circular focal lesion readily identifiable in vivo by fundus examination, which showed within the PCAs a progressive thinning of the outer retinal layer, and a diminution of the S-cone population to 19% by 30 d. In parallel to S-cone loss, activated Iba-1+ cells delineated the lesioned area and acquired an ameboid morphology with peak expression at 3 d after LIP. Iba-1+ cells adopted a more relaxed-branched morphology at 7 d and by 14-30 d their morphology was fully branched. CONCLUSION: LIP caused a progressive reduction of the outer retina with loss of S cones and a parallel dynamic activation of microglial cells in the lesioned area.

Bone Marrow-Derived Mononuclear Cell Transplants Decrease Retinal Gliosis in Two Animal Models of Inherited Photoreceptor Degeneration.

Inherited photoreceptor degenerations are not treatable diseases and a frequent cause of blindness in working ages. In this study we investigate the safety, integration and possible rescue effects of intravitreal and subretinal transplantation of adult human bone-marrow-derived mononuclear stem cells (hBM-MSCs) in two animal models of inherited photoreceptor degeneration, the P23H-1 and the Royal College of Surgeons (RCS) rat. Immunosuppression was started one day before the injection and continued through the study. The hBM-MSCs were injected in the left eyes and the animals were processed 7, 15, 30 or 60 days later. The retinas were cross-sectioned, and L- and S- cones, microglia, astrocytes and Müller cells were immunodetected. Transplantations had no local adverse effects and the CD45+ cells remained for up to 15 days forming clusters in the vitreous and/or a 2-3-cells-thick layer in the subretinal space after intravitreal or subretinal injections, respectively. We did not observe increased photoreceptor survival nor decreased microglial cell numbers in the injected left eyes. However, the injected eyes showed decreased GFAP immunoreactivity. We conclude that intravitreal or subretinal injection of hBM-MSCs in dystrophic P23H-1 and RCS rats causes a decrease in retinal gliosis but does not have photoreceptor neuroprotective effects, at least in the short term. However, this treatment may have a potential therapeutic effect that merits further investigation.

Pigment Epithelium-Derived Factor (PEDF) Fragments Prevent Mouse Cone Photoreceptor Cell Loss Induced by Focal Phototoxicity In Vivo.

Here, we evaluated the effects of PEDF (pigment epithelium-derived factor) and PEDF peptides on cone-photoreceptor cell damage in a mouse model of focal LED-induced phototoxicity (LIP) in vivo. Swiss mice were dark-adapted overnight, anesthetized, and their left eyes were exposed to a blue LED placed over the cornea. Immediately after, intravitreal injection of PEDF, PEDF-peptide fragments 17-mer, 17-mer[H105A] or 17-mer[R99A] (all at 10 pmol) were administered into the left eye of each animal. BDNF (92 pmol) and bFGF (27 pmol) injections were positive controls, and vehicle negative control. After 7 days, LIP resulted in a consistent circular lesion located in the supratemporal quadrant and the number of S-cones were counted within an area centered on the lesion. Retinas treated with effectors had significantly greater S-cone numbers (PEDF (60%), 17-mer (56%), 17-mer [H105A] (57%), BDNF (64%) or bFGF (60%)) relative to their corresponding vehicle groups (≈42%). The 17-mer[R99A] with no PEDF receptor binding and no neurotrophic activity, PEDF combined with a molar excess of the PEDF receptor blocker P1 peptide, or with a PEDF-R enzymatic inhibitor had undetectable effects in S-cone survival. The findings demonstrated that the cone survival effects were mediated via interactions between the 17-mer region of the PEDF molecule and its PEDF-R receptor.

ß-alanine supplementation induces taurine depletion and causes alterations of the retinal nerve fiber layer and axonal transport by retinal ganglion cells.

To study the effect of taurine depletion induced by ß-alanine supplementation in the retinal nerve fiber layer (RNFL), and retinal ganglion cell (RGC) survival and axonal transport. Albino Sprague-Dawley rats were divided into two groups: one group received ß-alanine supplementation (3%) in the drinking water during 2 months to induce taurine depletion, and the other group received regular water. After one month, half of the rats from each group were exposed to light. Retinas were analyzed in-vivo using Spectral-Domain Optical Coherence Tomography (SD-OCT). Prior to processing, RGCs were retrogradely traced with fluorogold (FG) applied to both superior colliculi, to assess the state of their retrograde axonal transport. Retinas were dissected as wholemounts, surviving RGCs were immunoidentified with Brn3a, and the RNFL with phosphorylated high-molecular-weight subunit of the neurofilament triplet (pNFH) antibodies. ß-alanine supplementation decreases significantly taurine plasma levels and causes a significant reduction of the RNFL thickness that is increased after light exposure. An abnormal pNFH immunoreactivity in some RGC bodies, their proximal dendrites and axons, and a further diminution of the mean number of FG-traced RGCs compared with Brn3a+RGCs, indicate that their retrograde axonal transport is affected. In conclusion, taurine depletion causes RGC loss and axonal transport impairment. Finally, our results suggest that care should be taken when ingesting ß-alanine supplements due to the limited understanding of their potential adverse effects.

Retinal Ganglion Cell Death as a Late Remodeling Effect of Photoreceptor Degeneration.

Inherited or acquired photoreceptor degenerations, one of the leading causes of irreversible blindness in the world, are a group of retinal disorders that initially affect rods and cones, situated in the outer retina. For many years it was assumed that these diseases did not spread to the inner retina. However, it is now known that photoreceptor loss leads to an unavoidable chain of events that cause neurovascular changes in the retina including migration of retinal pigment epithelium cells, formation of "subretinal vascular complexes", vessel displacement, retinal ganglion cell (RGC) axonal strangulation by retinal vessels, axonal transport alteration and, ultimately, RGC death. These events are common to all photoreceptor degenerations regardless of the initial trigger and thus threaten the outcome of photoreceptor substitution as a therapeutic approach, because with a degenerating inner retina, the photoreceptor signal will not reach the brain. In conclusion, therapies should be applied early in the course of photoreceptor degeneration, before the remodeling process reaches the inner retina.

Melanopsin+RGCs Are fully Resistant to NMDA-Induced Excitotoxicity.

We studied short- and long-term effects of intravitreal injection of N-methyl-d-aspartate (NMDA) on melanopsin-containing (m+) and non-melanopsin-containing (Brn3a+) retinal ganglion cells (RGCs). In adult SD-rats, the left eye received a single intravitreal injection of 5µL of 100nM NMDA. At 3 and 15 months, retinal thickness was measured in vivo using Spectral Domain-Optical Coherence Tomography (SD-OCT). Ex vivo analyses were done at 3, 7, or 14 days or 15 months after damage. Whole-mounted retinas were immunolabelled for brain-specific homeobox/POU domain protein 3A (Brn3a) and melanopsin (m), the total number of Brn3a+RGCs and m+RGCs were quantified, and their topography represented. In control retinas, the mean total numbers of Brn3a+RGCs and m+RGCs were 78,903 ± 3572 and 2358 ± 144 (mean ± SD; n = 10), respectively. In the NMDA injected retinas, Brn3a+RGCs numbers diminished to 49%, 28%, 24%, and 19%, at 3, 7, 14 days, and 15 months, respectively. There was no further loss between 7 days and 15 months. The number of immunoidentified m+RGCs decreased significantly at 3 days, recovered between 3 and 7 days, and were back to normal thereafter. OCT measurements revealed a significant thinning of the left retinas at 3 and 15 months. Intravitreal injections of NMDA induced within a week a rapid loss of 72% of Brn3a+RGCs, a transient downregulation of melanopsin expression (but not m+RGC death), and a thinning of the inner retinal layers.

Light-induced retinal degeneration causes a transient downregulation of melanopsin in the rat retina.

In this work we study the effects of an acute light-induced retinal degeneration on the population of melanopsin positive retinal ganglion cells (m+RGCs) and the expression of the melanopsin protein in the retina. The m+RGCs may be more resistant than other RGCs to lesion, but the effects of an acute light exposure in this population are unknown. Albino rats were exposed to white light (3000 lux) continuously for 48 h and processed 0, 3, 7 or 30 days after light exposure (ALE). Whole-mounted retinas were immunodetected with antibodies against melanopsin, Brn3a, and rhodopsin to study the populations of m+RGC, Brn3a+RGC and rods (which are the most abundant photoreceptors in the rat retina). Three days ALE there was substantial rod loss in an arciform area of the superior retina and with time this loss expanded in the form of rings all throughout the retina. Light exposure did not affect the number of Brn3a+RGCs but diminished the numbers of m+RGCs. Immediately ALE there was a significant decrease in the mean number of immunodetected m+RGCs that was more marked in the superior retina. Later, the number of m+RGCs increased progressively and reached normal values one month ALE. Western blot analysis showed that melanopsin expression down-regulates shortly ALE and recovers thereafter, in accordance with the anatomical data. This study demonstrates that there is a transient downregulation of melanopsin expression in the RGCs during the first month ALE. Further studies would be needed to clarify the long-term effect of light exposure on the m+RGC population.

Dose-Related Side Effects of Intravitreal Injections of Humanized Anti-Vascular Endothelial Growth Factor in Rats: Glial Cell Reactivity and Retinal Ganglion Cell Loss.

Purpose: In a previous study, we documented that the Intravitreal injections (IVIs) of bevacizumab in rats caused a retinal inflammatory response. We now study whether the IVI of other humanized anti-VEGF: ranibizumab and aflibercept also cause an inflammatory reaction in the rat retina and if it depends on the dose administered. Finally, we study whether this reaction affects retinal ganglion cell (RGC) survival. Methods: Albino Sprague-Dawley rats received a single IVI of 5 µL of PBS or ranibizumab or aflibercept at the concentration used in clinical practice (10 µg/µL or 40 µg/µL) or at a lower concentration (0.38 µg/µL and 1.5 µg/µL) calculated to obtain within the rat eye the same concentration as in the human eye in clinical practice. Others received a single 5 µL IVI of a polyclonal goat anti-rat VEGF (0.015 µg/µL) or of vehicle (PBS). Animals were processed 7 days or 1 month later. Retinal whole mounts were immunolabeled for the detection of microglial, macroglial, RGCs, and intrinsically photosensitive RGCs (ipRGCs). Fluorescence and confocal microscopy were used to examine retinal changes, and RGCs and ipRGCs were quantified automatically or semiautomatically, respectively. Results: All the injected substances including the PBS induced detectable side effects, namely, retinal microglial cell activation and retinal astrocyte hypertrophy. However, there was a greater microglial and macroglial response when the higher concentrations of ranibizumab and aflibercept were injected than when PBS, the antibody anti-rat VEGF and the lower concentrations of ranibizumab or aflibercept were injected. The higher concentration of ranibizumab and aflibercept resulted also in significant RGC death, but did not cause appreciable ipRGC death. Conclusions: The IVI of all the substances had some retinal inflammatory effects. The IVI of humanized anti-VEGF to rats at high doses cause important side effects: severe inflammation and RGC death, but not ipRGC death.

Evaluation of the neuroprotective efficacy of the gramine derivative ITH12657 against NMDA-induced excitotoxicity in the rat retina.

Purpose: The aim of this study was to investigate, the neuroprotective effects of a new Gramine derivative named: ITH12657, in a model of retinal excitotoxicity induced by intravitreal injection of NMDA. Methods: Adult Sprague Dawley rats received an intravitreal injection of 100 mM NMDA in their left eye and were treated daily with subcutaneous injections of ITH12657 or vehicle. The best dose-response, therapeutic window study, and optimal treatment duration of ITH12657 were studied. Based on the best survival of Brn3a + RGCs obtained from the above-mentioned studies, the protective effects of ITH12657 were studied in vivo (retinal thickness and full-field Electroretinography), and ex vivo by quantifying the surviving population of Brn3a + RGCs, αRGCs and their subtypes α-ONsRGCs, α-ONtRGCs, and α-OFFRGCs. Results: Administration of 10 mg/kg ITH12657, starting 12 h before NMDA injection and dispensed for 3 days, resulted in the best significant protection of Brn3a + RGCs against NMDA-induced excitotoxicity. In vivo, ITH12657-treated rats showed significant preservation of retinal thickness and functional protection against NMDA-induced retinal excitotoxicity. Ex vivo results showed that ITH12657 afforded a significant protection against NMDA-induced excitotoxicity for the populations of Brn3a + RGC, αRGC, and αONs-RGC, but not for the population of αOFF-RGC, while the population of α-ONtRGC was fully resistant to NMDA-induced excitotoxicity. Conclusion: Subcutaneous administration of ITH12657 at 10 mg/kg, initiated 12 h before NMDA-induced retinal injury and continued for 3 days, resulted in the best protection of Brn3a + RGCs, αRGC, and αONs-RGC against excitotoxicity-induced RGC death. The population of αOFF-RGCs was extremely sensitive while α-ONtRGCs were fully resistant to NMDA-induced excitotoxicity.

Methods to Identify Rat and Mouse Retinal Ganglion Cells in Retinal Flat-Mounts.

The identification of distinct retinal ganglion cell (RGC) populations in flat-mounted retinas is key to investigating pathological or pharmacological effects in these cells. In this chapter, we review the main techniques for detecting the total population of RGCs and various of their subtypes in whole-mounted retinas of pigmented and albino rats and mice, four of the animal strains most studied by the scientific community in the retina field. These methods are based on the studies published by the Vidal-Sanz's laboratory.

Bone marrow-derived mononuclear stem cells in the treatment of retinal degenerations.

Retinal degenerative diseases affecting the outer retina in its many forms (inherited, acquired or induced) are characterized by photoreceptor loss, and represent currently a leading cause of irreversible vision loss in the world. At present, there are very few treatments capable of preventing, recovering or reversing photoreceptor degeneration or the secondary retinal remodeling, which follows photoreceptor loss and can also cause the death of other retinal cells. Thus, these diseases are nowadays one of the greatest challenges in the field of ophthalmological research. Bone marrow derived-mononuclear stem cell transplantation has shown promising results for the treatment of photoreceptor degenerations. These cells may have the potential to slow down photoreceptor loss, and therefore should be applied in the early stages of photoreceptor degenerations. Furthermore, because of their possible paracrine effects, they may have a wide range of clinical applications, since they can potentially impact on several retinal cell types at once and photoreceptor degenerations can involve different cells and/or begin in one cell type and then affect adjacent cells. The intraocular injection of bone marrow derived-mononuclear stem cells also enhances the outcomes of other treatments aimed to protect photoreceptors. Therefore, it is likely that future investigations may combine bone marrow derived-mononuclear stem cell therapy with other systemic or intraocular treatments to obtain greater therapeutic effects in degenerative retinal diseases.

Intravitreal and subretinal syngeneic bone marrow mononuclear stem cell transplantation improves photoreceptor survival but does not ameliorate retinal function in two rat models of retinal degeneration.

PURPOSE: To study and compare effects of syngeneic bone marrow mononuclear stem cells (BM-MNCs) transplants on inherited retinal degeneration in two animal models with different etiologies: the RCS and the P23H-1 rats. To compare the safety and efficacy of two methods of intraocular delivery: subretinal and/or intravitreal. METHODS: A suspension of BM-MNCs was injected subretinally or intravitreally in the left eyes of P23H-1 and RCS rats at post-natal day (P) 21. At different survival intervals after the injection: 7, 15, 30 or 60 days, the retinas were cross-sectioned, and photoreceptor survival and glial cell responses were investigated using immunodetection of cones (anti-cone arrestin), synaptic connections (anti-bassoon), microglia (anti-Iba-1), astrocytes and Müller cells (anti-GFAP). Electroretinographic function was also assessed longitudinally. RESULTS: Intravitreal injections (IVIs) or subretinal injections (SRIs) of BM-MNCs did not produce adverse effects. The transplanted cells survived for up to 15 days but did not penetrate the retina. Both IVIs and SRIs increased photoreceptor survival, decreased synaptic degeneration and glial fibrillary acidic protein (GFAP) expression in Müller cells but did not modify microglial cell activation and migration or the electroretinographic responses. CONCLUSIONS: Intravitreal and subretinal syngeneic BM-MNCs transplantation decreases photoreceptor degeneration and shows anti-gliotic effects on Müller cells but does not ameliorate retinal function. Moreover, syngeneic BM-MNCs transplants are more effective than the xenotransplants of these cells. BM-MNC transplantation has potential therapeutic effects that merit further investigation.

Alpha retinal ganglion cells in pigmented mice retina: number and distribution.

Purpose: To identify and characterize numerically and topographically the population of alpha retinal ganglion cells (αRGCs) and their subtypes, the sustained-response ON-center αRGCs (ONs-αRGCs), which correspond to the type 4 intrinsically photosensitive RGCs (M4-ipRGCs), the transient-response ON-center αRGCs (ONt-αRGCs), the sustained-response OFF-center αRGCs (OFFs-αRGCs), and the transient-response OFF-center αRGCs (OFFt-αRGCs) in the adult pigmented mouse retina. Methods: The αRGC population and its subtypes were studied in flat-mounted retinas and radial sections immunodetected against non-phosphorylated high molecular weight neurofilament subunit (SMI-32) or osteopontin (OPN), two αRGCs pan-markers; Calbindin, expressed in ONs-αRGCs, and amacrines; T-box transcription factor T-brain 2 (Tbr2), a key transcriptional regulator for ipRGC development and maintenance, expressed in ipRGCs and GABA-displaced amacrine cells; OPN4, an anti-melanopsin antibody; or Brn3a and Brn3c, markers of RGCs. The total population of RGCs was counted automatically and αRGCs and its subtypes were counted manually, and color-coded neighborhood maps were used for their topographical representation. Results: The total mean number of αRGCs per retina is 2,252 ± 306 SMI32+αRGCs and 2,315 ± 175 OPN+αRGCs (n = 10), representing 5.08% and 5.22% of the total number of RGCs traced from the optic nerve, respectively. αRGCs are distributed throughout the retina, showing a higher density in the temporal hemiretina. ONs-αRGCs represent ≈36% [841 ± 110 cells (n = 10)] of all αRGCs and are located throughout the retina, with the highest density in the temporal region. ONt-αRGCs represent ≈34% [797 ± 146 cells (n = 10)] of all αRGCs and are mainly located in the central retinal region. OFF-αRGCs represent the remaining 32% of total αRGCs and are divided equally between OFFs-αRGCs and OFFt-αRGCs [363 ± 50 cells (n = 10) and 376 ± 36 cells (n = 10), respectively]. OFFs-αRGCs are mainly located in the supero-temporal peripheral region of the retina and OFFt-αRGCs in the mid-peripheral region of the retina, especially in the infero-temporal region. Conclusions: The combination of specific antibodies is a useful tool to identify and study αRGCs and their subtypes. αRGCs are distributed throughout the retina presenting higher density in the temporal area. The sustained ON and OFF response subtypes are mainly located in the periphery while the transient ON and OFF response subtypes are found in the central regions of the retina.

University students fail to comply with contact lens care.

PURPOSE: To assess the level of compliance related to contact lens (CL) wear in university students in Spain. METHODS: A web-based questionnaire was distributed to university students through their representatives to assess general demographic information, questions related to CL history, level of compliance with CL care and CL-related complications. RESULTS: A total of 266 participants with an average age of 22 (±4.5) years completed the online questionnaire. Only 39.1 % of respondents indicated that they always replace their CLs within the recommended schedule, and 63.6 % indicated that they usually wear their CLs more hours per day than recommended. Surprisingly, 64.9 % of participants reported that they had not been informed about the potential risks of CL wear, and only 20 % indicated that they always comply with follow-up visits, whereas 42.1 % of respondents expose their CL to water frequently. Participants who received proper CL education were more likely to attend aftercare visits (X2(2) = 9.104, p < 0.05). Participants with a longer history of CL wear had a greater tendency to expose their CLs to water (X2(6) = 18.768, p < 0.05) and suffer CL-related problems (X2(3) = 12.183, p < 0.05). There was also a relationship between an increased frequency of CL exposure to water and an increased tendency to experience CL-related adverse events (X2(2) = 10.864, p < 0.05). CONCLUSION: A relatively high percentage of university CL wearers displayed some degree of non-compliance, which emphasises the importance of providing accurate and comprehensive CL care guidelines and attending aftercare visits to minimise potential CL-related complications. CL wearers should be provided with clear and unambiguous guidelines to avoid any exposure of CL's and CL cases to water.