Transpupillary retinal photocoagulations were performed on ten eyes of five pigmented rabbits using a diode laser (Nidek Co., LTD, Aichi, Japan) emitting infrared radiation at 800 nm wavelength. A histological and an ultrastructural study on the treated eyes were done at 1, 3, 5, and 7 days after retinal photocoagulations. The purpose of this study was to observe the sequential changes in the retina and the choroid following transpupillary diode laser retinal photocoagulations at the parameters of laser power which produced a grayish white retinal discoloration with distinct white center. It seemed that the lesion was grade 3 retinal photocoagulation by Tso et al's classification. It appeared that the parameters necessary to produce grade 3 photocoagulation lesions were 160 mW power, and 0.2 second duration at 200 microns size. In general, with an agreement to other reports, histologic study of the diode laser lesions showed that the outer retina was damaged more severely than the inner retina. However, on day 1 after laser treatment, the alterations were more profound in the inner retina than in the outer retina and an occasional swelling of the axons in the nerve fiber layer was observed on the ultrastructural study. The results observed have not been found in other previous studies and suggest that the inner retina might be injured directly by 800 nm wavelength diode laser radiations. Thus we could conclude that 800 nm wavelength diode radiation might be absorbed by melanin pigment and also by other chromophores contained in inner retinal tissues. Further studies must follow to verify the laser-tissue interactions in diode laser retinal photocoagulations.
Animals ; Laser Coagulation/*adverse effects ; Rabbits ; Retina/pathology/*radiation effects/ultrastructure

OBJECTIVETo investigate the injury effects of microwave on the visual performance and the apoptosis of retinal ganglion cells (RGCs) in rats and the relationship between the impaired visual performance and RGCs apoptosis induced by microwave.

METHODSThe visual performance of rats was observed by Electroretinogram (ERG) and Flash visual evoked potentials (F-VEP). The apoptosis of RGCs in vivo and in vitro was detected by TUNEL assay and Hoechst staining.

RESULTSMicrowave exposure had no influence on ERG-a wave. The amplitude of ERG-b wave decreased significantly on the 3rd day and 7th day after microwave exposure (P < 0.01).The latency of ERG-b wave shortened significantly only at 3rd day after microwave exposure (P < 0.01). The latency of F-VEP extended markedly on the 3rd day after exposure (P < 0.05) and recovered on the 7th day after microwave exposure. The amplitude of F-VEP decreased significantly in exposure group, as compared with sham-exposure group, on the 3rd day and 7th day after microwave exposure (P < 0.05). After microwave exposure for 12 h, the apoptotic rate of RGCs in rat increased from 2.85% to 6.73%, and on the 7th day after exposure, the apoptotic rate of RGCs remained 8.93% (P < 0.05). The apoptotic rate of cultured RGCs increased from 8.42% to 13.91% at 6 hour (P < 0.05) and to 24.14% at 24 hour (P < 0.01) after microwave exposure (P < 0.05 or P < 0.01).

CONCLUSIONMicrowave exposure can injure the visual performance of rats, and the apoptosis of RGCs induced microwave may be one of the main pathological mechanisms.

Animals ; Apoptosis ; radiation effects ; Cells, Cultured ; Male ; Microwaves ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Retina ; radiation effects ; Retinal Ganglion Cells ; pathology ; radiation effects

OBJECTIVETo investigate the role of Caspase-3 in retinal damage caused by light exposure in rats.

METHODSLight injury to retina was induced by persistent exposure to illumination (intensity: 30 000 +/- 50 lux) of operating microscope for 30 minutes in the right eyes of Sprague-Dawley rats. The pathological changes of retina were observed under optical and electron microscopies at different time points, which were 6 hours, 1, 3, 7, and 15 days after the light exposure. Apoptosis of retinal cells was analyzed by flow cytometry. The activity of Caspase-3 was evaluated by using the Caspase-3 assay kit. At the same time, the expression of Caspase-3 protease was determined with Western blot analysis.

RESULTSThe examination results of optical and transmission electron microscopes showed that edema of inner and outer segments of the retina, especially the chondriosome inside the inner segment, became obvious 6 hours after the light exposure. The change was deteriorated along with the increasing time. The structures of the discoidal valve dissociated in the outer segment simultaneously. Disorderly arranged nuclei, karyopycnosis, and thinning in the outer nuclear layer were observed. The retinal pigment epithelium almost disappeared during the later stage. The staining results of Annexin-V combined with PI demonstrated that the proportion of apoptotic cells increased with time. The proportion between 7th day (82.7%) and 15th day (80.4%), however, showed no significant difference. Caspase-3 became remarkably active with the lapse of time, which increased from 0.02 at 6th hour to the peak of 9.8 at 7th day before it started to descend. The Western blot detected a expression of the active form of Caspase-3 at 7th day and 15th day.

CONCLUSIONApoptosis of photoreceptor cells is markedly involved in the light damage and Caspase-3 protease may play an important role in the apoptotic process of the retina after light exposure in rats.

Animals ; Apoptosis ; radiation effects ; Caspase 3 ; genetics ; metabolism ; radiation effects ; Dose-Response Relationship, Radiation ; Enzyme Activation ; Gene Expression Regulation, Enzymologic ; radiation effects ; Light ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Retina ; enzymology ; pathology ; radiation effects ; ultrastructure

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

PURPOSE: To report of photic retinopathy induced by plasma arc welding, and the OCT (optical coherence tomography) results of damaged retinal lesions. METHODS: We describe a case report of a 37-year-old male, working in the steel industry, who presented with central scotoma in both eyes. RESULTS: On his first visit, one day after performing plasma arc welding with protective gear at work, his best corrected vision was 0.7 for both eyes. Ophthalmic examination of the fundus showed a round yellow lesion with an approximate size of 300 micrometers superonasal to the fovea of both eyes. On his next visit, one month later, his vision had recovered to 1.0, his symptoms had improved, and the ophthalmoscopic examination of the fundus revealed that the round yellow spots had disappeared from both eyes. CONCLUSIONS: To our knowledge, this is the first report of photic retinopathy induced by plasma arc welding, and the OCT (optical coherence tomography) results of damaged retinal lesions have not previously been reported. For these reasons, we report this case.
*Welding ; Trauma Severity Indices ; Tomography, Optical Coherence ; Retinal Diseases/*etiology/pathology ; Retina/*injuries/pathology/radiation effects ; Male ; Light/*adverse effects ; Humans ; Fundus Oculi ; Fluorescein Angiography ; Eye Burns/*complications/pathology ; Diagnosis, Differential ; Adult ; *Accidents, Occupational

Exposure to light can induce photoreceptor cell death and exacerbate retinal degeneration. In this study, mice with genetic knockout of several genes, including rhodopsin kinase (Rhok-/-), arrestin (Sag-/-), transducin (Gnat1-/-), c-Fos (c-Fos-/-) and arrestin/transducin (Sag-/-/Gnat1-/-), were examined. We measured the expression levels of thousands of genes in order to investigate their roles in phototransduction signaling in light-induced retinal degeneration using DNA microarray technology and then further explored the gene network using pathway analysis tools. Several cascades of gene components were induced or inhibited as a result of corresponding gene knockout under specific light conditions. Transducin deletion blocked the apoptotic signaling induced by exposure to low light conditions, and it did not require c-Fos/AP-1. Deletion of c-Fos blocked the apoptotic signaling induced by exposure to high intensity light. In the present study, we identified many gene transcripts that are essential for the initiation of light-induced rod degeneration and proposed several important networks that are involved in pro- and anti-apoptotic signaling. We also demonstrated the different cascades of gene components that participate in apoptotic signaling under specific light conditions.
Animals ; Apoptosis/radiation effects ; G-Protein-Coupled Receptor Kinase 1/genetics ; GTP-Binding Protein alpha Subunits/genetics ; *Gene Expression Profiling ; Genes, fos/genetics ; Light/adverse effects ; Light Signal Transduction/*genetics/physiology/radiation effects ; Mice ; Mice, Knockout ; Oligonucleotide Array Sequence Analysis ; Retina/metabolism/pathology/radiation effects ; Retinal Degeneration/etiology/*genetics/physiopathology ; Transducin/genetics

The purpose of this article is to compare spectral-domain (SD) and time-domain (TD) optical coherence tomography (OCT) findings in patients with solar retinopathy. Complete ocular examinations and OCT were performed in two patients presenting with acute solar retinopathy soon after observation of an eclipse. Both patients were evaluated with SD-OCT and TD-OCT at the same time. SD-OCT demonstrated characteristic defects at the level of the inner and outer segment junction of the photoreceptors in all the affected eyes and decreased reflectiveness of the retinal pigment epithelium layer. TD-OCT images showed unremarkable findings in two eyes with deteriorated visual acuity. SD-OCT improves diagnosis and assessment of the degree and nature of foveal damage in patients with solar retinopathy and may be an important tool for use in identifying foveal damage not detected by TD-OCT. SD-OCT may be preferable to TD-OCT for confirmation or assessment of the degree of foveal damage in patients with solar retinopathy.
Child ; Eye Burns/complications/*diagnosis ; Follow-Up Studies ; Humans ; Male ; Retina/pathology/*radiation effects ; Retinal Diseases/*diagnosis/etiology ; Sunburn/complications/*diagnosis ; Time Factors ; Tomography, Optical Coherence/*methods ; Trauma Severity Indices ; Visual Acuity ; Visual Fields ; Young Adult

A 37-year-old female, who had received modified radical mastectomy for cancer of her right breast, presented with decreased visual acuity in the left eye after radiation therapy for the management of the metastasis to her right brain 14 months ago. After ocular examination, we diagnosed her as radiation retinopathy. At the time of the first visit, the corrected best visual acuity was 0.4 in the left eye, and fundus examination revealed cotton wool spots and cystoid macular edema (CME). The findings in the right eye were normal except for cotton wool spots in the superior major arch. Fluorescein angiography (FA) showed marked telangiectasia and microaneurysms in her left eye but tiny microaneurysms in her right eye. Subsequent optical coherent tomography (OCT) showed CME. We injected intravitreal triamcinolone acetonide (TA). Two weeks after treatment, the visual acuity was improved to 0.6 and the retinal thickness was decreased. Three months later, the visual acuity in the left eye was dropped to 0.3 due to the recurrence of CME, so we injected intravitreal TA again. Five months later, visual acuity was improved to 0.5 and OCT revealed the improvement of CME. The incidence of radiation retinopathy is higher in the side nearer to radiation, but careful radiation blocking is also required on the opposite side of irradiation site considering the possibility of radiation retinopathy and careful observation is required on both sides of the eyes when performing fundus examination.
Adult ; Brain Neoplasms/*radiotherapy/secondary ; Breast Neoplasms/pathology/radiotherapy/surgery ; Diagnosis, Differential ; Female ; Fluorescein Angiography ; Follow-Up Studies ; Fundus Oculi ; Glucocorticoids/administration & dosage ; Humans ; Radiation Injuries/diagnosis/drug therapy/*etiology ; Retina/pathology/*radiation effects ; Retinal Diseases/diagnosis/drug therapy/*etiology ; Tomography, Optical Coherence ; Triamcinolone Acetonide/administration & dosage