In order to study the functional and structural alterations of the retina in SD rat model after methanol intoxication, 35 rats were divided randomly into five groups administrated with saline, 3-day high dose, 7-day high dose, 3-day low dose and 7-day low dose methanol separately. The retinal function of each group was assessed by flash electroretinogram (F-ERG) 3 and 7 days after methanol poisoning. The microstructure and ultrastructure of the retina were observed at the same time. The high-dose methanol intoxication induced irreversible retinal functional and structural damages 3 days after poisoning, which included prolonged latency and reduced amplitude of the Max-reaction of F-ERG. These injuries were aggravated 7 days after poisoning. Meanwhile, the latency and amplitude of the Cone-reaction of F-ERG were also affected 3 days after poisoning, but there were no further worsening tendency 7 days after poisoning. The retinal histological analysis showed cellular edema, heteromorphy and disarrangement, tissular loosen of the inner nuclear layer and photoreceptors layer. The mitochondrial damage began at the photoreceptors layer and developed further into the inner nuclear layer. The low-dose methanol intoxication only caused transient damage of the retina. Our results showed that the function and structure of the photoreceptor and inner nuclear layer were the primary target of methanol intoxication and that the rod cells were more sensitive to methanol intoxication than the cone cells. The mitochondrial damage developed from outer layer to inner layer of the retina.
Animals ; Edema/pathology* ; Electroretinography ; Forensic Medicine ; Male ; Methanol/poisoning* ; Mitochondria/pathology* ; Photoreceptor Cells/pathology* ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Retina/physiopathology* ; Retinal Cone Photoreceptor Cells/pathology* ; Retinal Diseases/pathology* ; Retinal Rod Photoreceptor Cells/pathology* ; Time Factors

OBJECTIVETo study the effect of Vaccinium uliginosum L., (VU) on the electroretinogram (ERG) and retinal pathological changes in rabbits after light-induced damage.

METHODSTwenty-eight Chinchilla rabbits were randomly divided into four groups: administration beforehand (A), administration after injury (B), light injury without administration (C), and blank (D) groups. After a 4-week administration of VU homogenate at 4.8 g/(kg·d) once a day in group A, ERG in groups A, B and C were recorded according to the standards set by the International Society for Clinical Electrophysiology of Vision (ISCEV). Except for group D, the groups were then exposed to strong light. Just after that, group A stopped receiving VU treatment and group B started to receive it. Then ERGs in all groups were recorded after 1 day, 1 week, and 2 weeks. Throughout the whole process groups which were not fed with VU were fed with normal saline. Finally, the tissues and structures of all the groups were observed and the thickness of the outer nuclear layers (ONL) was measured.

RESULTS(1) After 4-week feeding with VU, the latency time of ERG in group A became shorter than those in the other groups and the amplitude increased. After being exposed to strong light, the latency time lengthened and amplitude decreased in all the injury groups, but comparing at each time point, the measured values in group A were better than those in group C. With the accumulation of VU, the ERG in group B improved, and finally, all of the detected values became better than those in group C. (2) Retinae in group D were normal in histology and the layers were in order but those in group C became disarranged. The injuries in groups A and B were minor compared with those in group C. The thickness of the ONL in group C was significantly thinner than in the other groups (P=0.000), and that in groups A and B was thicker than that in group C, although thinner than in group D. That in group A was thicker than in group B.

CONCLUSIONSVU can relieve the injury to rabbit retinae exposed to normal day and night rhythm, alleviate the harm caused by light when used beforehand, and repair the light damage to the retina.

Animals ; Electroretinography ; Light ; Plant Extracts ; pharmacology ; Rabbits ; Retina ; drug effects ; pathology ; physiopathology ; radiation effects ; Retinal Cone Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Retinal Rod Photoreceptor Cells ; drug effects ; pathology ; radiation effects ; Time Factors ; Vaccinium ; chemistry

Solar retinopathy is an injury of the retinal photoreceptors due to excessive exposure to the solar radiation. Diagnosis of the disease is challenging and requires combination of a detailed history and imaging modalities. This case report focuses on a 55-year-old fruit picker with an irreversible central scotoma of the right eye. A diagnosis of solar retinopathy was made based on history but mainly by several imaging modalities, such as optical coherence tomography (OCT), infrared (IF) imaging of the fundus and fundus autofluorescence (FAF). Electroretinogram (ERG)showed flattened and reduced waves in both scotopic and photopic response. Fundus angiography (FA) revealed no obvious telangectatic vessels. In conclusion, solar retinopathy is a disease where multimodal imaging may play an important role in the diagnosis. The condition may be irreversible thus advocating protective eyewear is mandatory in patients who are chronically exposed to the sun.
Photoreceptor Cells, Vertebrate

The ubiquitous Na, K-ATPase is a membrane-bound ion pump located in the plasma membrane in all animal cells and plays an essential role in a variety of cellular functions. Studies in several organisms have shown that this protein regulates different aspects of embryonic development and is responsible for the pathogenesis of several human diseases. Na, K-ATPase is an important factor for retinal development, and combinations of the isoforms of each of its subunits are expressed in different cell types and determine its functional properties. In this study, we performed RT-PCR assay to determine temporal expression and in situ hybridization to determine spatial expression of Na, K-ATPase beta2 isoform (atp1b2) in Xenopus laevis. Focusing on retinal expression to distinguish the specific expression domain, we used retinal marker genes sox4, sox11, vsx1, and . Xenopus atp1b2 was expressed from late gastrulation to the tadpole stage. Using whole mount in situ hybridization, we showed that Xenopus atp1b2 was expressed broadly in the eye, the whole surface ectoderm, and gills. In situ hybridization on sections revealed detailed and specific expression in the outer nuclear layer of the retina, which consists of two major classes of photoreceptors, rods and cones, surface ectoderm, pharyngeal epithelium, and gills. These findings indicate that atp1b2 may play an important role for the development of Xenopus retina.
Animals ; Cell Membrane ; Ectoderm ; Embryonic Development ; Epithelium ; Female ; Gastrulation ; Gills ; Humans ; In Situ Hybridization ; Ion Pumps ; Larva ; Pregnancy ; Protein Isoforms ; Retina* ; Retinal Rod Photoreceptor Cells ; Retinaldehyde ; Xenopus laevis ; Xenopus*

Animals ; Cell Survival ; radiation effects ; Light ; adverse effects ; Mice ; Mice, Knockout ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; antagonists & inhibitors ; metabolism ; Retinal Rod Photoreceptor Cells ; cytology ; enzymology ; radiation effects

Animals ; Embryo, Mammalian ; Humans ; Photoreceptor Cells, Vertebrate ; metabolism ; physiology ; Retinal Ganglion Cells ; metabolism ; physiology ; Retinal Pigments ; metabolism

It already has been known that various ions were participated in phototransduction mechanism of the vertebrate photoreceptor during the visual adaptation. The vitreous humor(VH)contains certain amount of Na+, K+ and Ca++ as well. However, the roles of these ions are unknown except functioning of metabolic process. Our preliminary electroretinogram(ERG) experiments suggested that the permeability of these ions has light dependent activity during the light illumination. We have supported this suggestion more tangibly by trying out various experiments with bullfrog eyes as a reference of visual adaptation. The results are summarized as follows: 1)According to our atomic absorption spectroscopic measurements, the concentration of Na+, K+ and Ca++ in light adapted VH was higher than that of dark adapted VH. This result indicated that the light-dependention transport systems which affect the ionic movements might be in internal limiting membrane(ILM). 2)The amplitude of ERG b-wave was reduced by concentration decrement of Na+ and concentration increment of K+ respectively. On the other hand, the elimination of Ca++ within ringer solution resulted in b-wave amplitude increment. 3)Treatment of Na+ hannel blockers(TTX, STX)and K+ channel blockers(Ba++, Cd++, Cs+, 4-AP and TEA)in the vitreous humor side induced the increment and the decrement of b-wave response respectively. Taken together, these results suggest that the light dependent Na+ K+ channels exist in the ILM of vertebrate retina which participates visual adaptation.
Absorption ; Hand ; Ions ; Light Signal Transduction ; Lighting ; Membranes* ; Metabolism ; Permeability ; Photoreceptor Cells, Vertebrate ; Rana catesbeiana ; Retina ; Vertebrates* ; Vitreous Body

PURPOSE: Sildenafil citrate (Viagra(R)) acts as a relatively specific inhibitor of the type 5 phosphodiesterase isoenzyme (PDE5) in the corpus cavernosum. But, it also has a mild inhibitory effect on PDE6 in the retinal photoreceptor. Therefore, we studied the ocular side effects of sildenafil. METHODS: We tested the visual acuity, intraocular pressure, color vision, visual evoked potential (VEP), electroretinogram (ERG), anterior segment and fundus appearance. All tests were done before and after medication of 50 mg and 100 mg sildenafil, respectively. RESULTS: There was no significant effect of sildenafil on visual acuity, intraocular pressure, color vision, VEP, anterior segment and fundus appearance. ERG changes after 50 mg sildenafil were not significant. The a-wave amplitude of the maximal combined response after 100 mg sildenafil showed significant changes (p=0.021). The b-wave amplitude of the maximal combined response after 100 mg sildenafil showed changes with borderline significance (p=0.059). CONCLUSIONS: In considering the fact that even single dose of 100 mg sildenafil showed changes on ERG, it seems that retinal function in patients receiving sildenafil for a longer period, especially in patients with underlying vascular abnormalities should be monitored by clinical and electrophysiologic tests.
Citric Acid ; Color Vision ; Eating* ; Evoked Potentials, Visual ; Humans ; Intraocular Pressure ; Photoreceptor Cells, Vertebrate ; Retinaldehyde ; Visual Acuity ; Sildenafil Citrate

PURPOSE: To evaluate the efficacy of anti-vascular endothelial growth factor (VEGF) compared with observation for treating acute central serous chorioretinopathy (CSC). METHODS: A retrospective study of 36 patients with acute CSC, including 21 patients treated with anti-VEGF (anti-VEGF group) and 15 patients with observation (observation group). Patients in the anti-VEGF group received a single dose of bevacizumab or ranibizumab at baseline. Best-corrected visual acuity (BCVA), central foveal thickness (CFT) and resolution of subretinal fluid (SRF) on optical coherence tomography (OCT) were assessed. The integrity of the foveal inner segment/outer segment (IS/OS) line at 12 months was also analyzed. RESULTS: Resolution of SRF was achieved in 20 of 21 eyes in the anti-VEGF group and in 12 of 15 eyes in the observation group (p = 0.151). Mean BCVA and CFT were not different between the two groups at 12 months (p > 0.05). The amount of change in BCVA, however, differed significantly between the groups (p = 0.044). Final OCT more frequently detected the foveal IS/OS line in the anti-VEGF group than in the observation group (p = 0.012). CONCLUSIONS: In terms of BCVA, anti-VEGF and observation only had similar therapeutic effects in acute CSC patients. In some patients, however, the rapid resolution of SRF by anti-VEGF might reduce the risk of photoreceptor degeneration and improve long-term visual acuity.
Acute Disease ; Adult ; Angiogenesis Inhibitors/*therapeutic use ; Bevacizumab/therapeutic use ; Central Serous Chorioretinopathy/*drug therapy/physiopathology ; Female ; Humans ; Intravitreal Injections ; Male ; Middle Aged ; Observation ; Ranibizumab/therapeutic use ; Retinal Photoreceptor Cell Inner Segment/pathology ; Retinal Photoreceptor Cell Outer Segment/pathology ; Retrospective Studies ; Subretinal Fluid/drug effects ; Tomography, Optical Coherence ; Vascular Endothelial Growth Factor A/antagonists & inhibitors ; Visual Acuity

PURPOSE: To investigate which spectral domain optical coherence tomography (SD-OCT) findings predict visual outcome after anti-vascular endothelial growth factor (VEGF) treatment in neovascular age-related macular degeneration (NV-AMD). METHODS: We reviewed the medical records of patients with treatment-naive NV-AMD who underwent three or more consecutive anti-VEGF injections. The patients were divided into three groups according to their changes of visual acuity (VA); improved (group I), static (group S), or worsened (group W). We assessed the incidences and values of all available SD-OCT findings of these groups, compared these findings between the three groups and compared the initial values with the post-treatment values. RESULTS: Better initial VA and longer external limiting membrane (ELM) length were associated with less change in VA after anti-VEGF treatment. The initial VA was mildly correlated with initial photoreceptor inner and outer segment junction (IS/OS) length and initial ELM length. The final VA was also mildly correlated with the final IS/OS length and the final ELM length. VA was significantly changed after anti-VEGF treatment in groups W and I. With regard to incidence, disruption of the IS/OS (IS/OS-D), disruption of the ELM (ELM-D) and ELM length differed significantly between the three groups, particularly ELM-D. The incidences of IS/OS-D and ELM-D in group I were significantly lower than those in groups S and W, and those in group S were also lower than those in group W. The ELM length in group I was significantly longer than it was in groups S and W, and the ELM length in group S was longer than that for group W. However, these three findings did not change after the anti-VEGF treatment. CONCLUSIONS: Initial IS/OS-D, ELM length and particularly ELM-D can be useful predictors of the visual outcome after anti-VEGF treatment in NV-AMD patients.
Aged ; Aged, 80 and over ; Angiogenesis Inhibitors/*therapeutic use ; Choroidal Neovascularization/*drug therapy/physiopathology ; Female ; Humans ; Intravitreal Injections ; Male ; Middle Aged ; Ranibizumab/*therapeutic use ; Retinal Photoreceptor Cell Inner Segment/pathology ; Retinal Photoreceptor Cell Outer Segment/pathology ; Tomography, Optical Coherence ; Vascular Endothelial Growth Factor A/antagonists & inhibitors ; Visual Acuity/*physiology ; Wet Macular Degeneration/*drug therapy/physiopathology