PURPOSE: To characterize the features of peripapillary atrophy (PPA), as imaged by spectral-domain optical coherence tomography (SD-OCT). METHODS: SD-OCT imaging of the optic disc was performed on healthy eyes, eyes suspected of having glaucoma, and eyes diagnosed with glaucoma. From the peripheral beta-zone, the retinal nerve fiber layer (RNFL), the junction of the inner and outer segments (IS/OS) of the photoreceptor layer, and the Bruch's membrane/retinal pigment epithelium complex layer (BRL) were visualized. RESULTS: Nineteen consecutive eyes of 10 subjects were imaged. The RNFL was observed in the PPA beta-zone of all eyes, and no eye showed an IS/OS complex in the beta-zone. The BRL was absent in the beta-zone of two eyes. The BRL was incomplete or showed posterior bowing in the beta-zone of five eyes. CONCLUSIONS: The common findings in the PPA beta-zone were that the RNFL was present, but the photoreceptor layer was absent. Presence of the BRL was variable in the beta-zone areas.
Adult ; Aged ; Bruch Membrane/pathology ; Female ; Glaucoma/*complications ; Humans ; Male ; Middle Aged ; Nerve Fibers/pathology ; Optic Atrophy/*diagnosis/*etiology ; Optic Disk/*pathology ; Photoreceptor Cells, Vertebrate/pathology ; Retina/pathology ; Retinal Pigment Epithelium/pathology ; Tomography, Optical Coherence/*methods

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

PURPOSE: We investigated structural changes in the retina by using optical coherence tomography (OCT) in a feline model of retinal degeneration using iodoacetic acid (IAA).METHODS: We examined 22 eyes of 11 felines over 2 years of age. The felines had fasted for 12 hours and were intravenously injected with IAA 20 mg/kg of body weight. OCT (Spectralis OCT) was performed at the point where the ends of the retinal vessels collected in the lateral direction from the optic nerve head and area centralis. Similarly, OCT was performed four times at 1-week intervals following injections, at which point the felines were sacrificed and histologic examinations were performed. Using OCT, the thickness of each layer of the retina was measured.RESULTS: The average body weight of the three male and eight female felines investigated in this study was 1.61 ± 0.19 kg. The mean total retinal thickness of the felines before injection was 221.32 ± 9.82 µm, with a significant decrease in the retinal thickness at 2, 3, and 4 weeks following injections of 186.41 ± 35.42, 174.56 ± 31.94, and 175.35 ± 33.84 µm, respectively (p = 0.028, 0.027, and 0.027, respectively). The thickness of the outer nuclear layer was 57.49 ± 8.03 µm before injection and 29.26 ± 17.87, 25.62 ± 13.88, and 31.60 ± 18.38 µm at 2, 3, and 4 weeks, respectively, after injection (p = 0.028, 0.028, 0.046, respectively).CONCLUSIONS: In a feline model of retinal degeneration using IAA, the total retinal thickness and the thickness of the outer nuclear layer were shown to decrease significantly on OCT.
Angiography ; Body Weight ; Female ; Humans ; Iodoacetic Acid ; Male ; Optic Disk ; Photoreceptor Cells, Vertebrate ; Retina ; Retinal Degeneration ; Retinal Vessels ; Retinaldehyde ; Tomography, Optical Coherence

The author studied the functional derangement of blood-retinal barrier induced by destruction of the pigment epithelial cells of the retina. Sodium iodate, which was well known to exert a selectively destructive action to the retinal pigment epithelial cells, was injected to the rabbits intravenously(60mg/kg of body weight). Eyes were enucleated 2 days and 4 days after sodium iodate injection and examined by electron microscope. Some of the tissue were fixed in colloid lanthanum, to investigate the changes of the permeability of plasma membrane in accordance with cellular damages induced by sodium iodate. The permeability of the blood-retinal barrier was also studied after intravenous(200mg/kg) or intraocular(4 microgram/20ml of saline) injection of horseradish peroxidase(HRP). The results obtained were summarized as the following: Sodium iodate induced patchy areas of loss of pigment epithelial cells after 2 days, which were more widespread and severe after 4 days with regenerative activities. Loss of outer segment and mitochondrial swelling of the inner segment of visual cells were also noted after 4 days. Colloidal lanthanum penetrated into the mitochondria of pigment epithelial cells at 2 days after sodium iodate injection, which was extended to the mitochondria of inner segment of visual cells after 4 days. Intraocularly injected HRP appeared from the internal limiting membrane to Bruch's membrane after 2 days. Intravenously injected HRP appeared from the Bruch's membrane to ganglion cell layer after 2 days, which were extended to the vitreal cavity. The results suggested that the damage of the pigment epithelial cells induced by sodium iodate destroy blood-retinal barrier. HRP exudation is more extensive in direction of retina to choroid than choroid to retina.
Armoracia ; Blood-Retinal Barrier* ; Bruch Membrane ; Cell Membrane ; Choroid ; Colloids ; Epithelial Cells ; Ganglion Cysts ; Lanthanum ; Membranes ; Mitochondria ; Mitochondrial Swelling ; Permeability ; Rabbits ; Retina ; Retinal Pigment Epithelium* ; Retinaldehyde* ; Sodium

The role of GABA or glycine as an inhibitory neurotransmitter is well established, and GABAergic or glycinergic neurons appear to play an important role in the mammalian retinas. It has been reported that certain amacrine, bipolar, displaced amacrine and ganglion cells are consistently labeled with anti-GABA or anti-glycine antisera in the mammalian retinae so far, and it has been suggested that colocalization of GABA and glycine within the retinal neurons could be common in the mammalian retina by recent immunecytochemical and electrophysiological studies. This study was conducted to localize GABAergic and glycinergic neurons and to define whether GABA and glycine are colocalized within same retinal neurons of the rat retina by immunocytochemical method using anti-GABA and anti-glycine antisera. The results were as follows : 1. GABAergic neurons of the rat retina were amacrine, interplexiform, bipolar, displaced amacrine and ganglion cells, and processes of GABAergic neurons formed dense networks with distinct two bands in the inner plexiform layer. 2. Glycinergic neurons were amacrine, bipolar, displaced amacrine and ganglion cells,and their processes were evenly distributed as dense networks through whole inner plexiform layer. 3. 28.5% of GABA immunoreactive amacrine cells and 9.8% of GABA immunoreactive bipolar cells located in the inner nuclear layer,and 11.9% of labeled neurons located in the ganglion cell layer showed glycine immunoreactivity in the rat retina. These results demonstrate that GABA and glycine, major inhibitory neurotransmitters, are colocalized within certain amacrine and displaced amacrine cells, and a few bipolar cells, and that neurons synthesizing and utilizing both GABA and glycine as their neurotransmitters may play an unique role in the visual processing in the rat retina.
Amacrine Cells ; Animals ; GABAergic Neurons ; gamma-Aminobutyric Acid* ; Ganglion Cysts ; Glycine* ; Immune Sera ; Neurons* ; Neurotransmitter Agents ; Rats* ; Retina* ; Retinal Neurons

Heme oxygenase (HO)-1 and -2 isozymes are important markers for the oxidative stress. We localized HO-1 and HO-2 immunoreactivities and assessed the effect of aging on distribution of HO in the young and aged rat retina by immunohistochemical method. HO-1 and HO-2 showed partly different patterns of localization, indicating possibilities of different regulation of these two isozymes in the retina. HO-2 immunoreactivity was localized to some retinal neurons in ganglion cell layer and inner nuclear layer involving both of plexiform layers and pigment epithelium. The distribution of HO-2 positive cells did not show any difference between aged and young rat. In the case of HO-1, the immunoreactivity is found in retinal layers except outer nuclear layer and layer of rods and cones of young rat retina. The distribution of HO-1 immunoreactivity in old rat retina does not show remarkable difference compared with that in young rat retina, except in inner nuclear layer, outer plexiform layer and pigment epithelium. HO-1 positive components increased in inner nuclear layer, and decreased in outer plexiform layer and pigment epithelium with aging. This may suggest that the possibility of decrease in HO-1 mediated protective function against oxidative stress in outer retinal region of old rat. Another isozyme, HO-2, may not be influenced by normal aging process in rat retina. However, the localization of HO-1 and HO-2 in retina suggests that these two isozymes contribute to visual impairment in normal aging process.
Aging ; Animals ; Epithelium ; Ganglion Cysts ; Heme Oxygenase (Decyclizing)* ; Heme* ; Immunohistochemistry ; Isoenzymes* ; Oxidative Stress ; Photoreceptor Cells, Vertebrate ; Rats* ; Retina* ; Retinal Neurons ; Retinaldehyde ; Vision Disorders

To compare the effect of centrally aligned image acquisitions with that of roughly centered image acquisitions on the reproducibility of topographic parameters obtained with the Heidelberg Retina Tomograph. three optic nerve head images were acquired sequentially by the rough centration of live image on the monitor, after then another three images sequentially by the central alignment in five healthy eyes of five subjects. For the centrally aligned image acquisitions, the contour of the frozen live optic nerve head image of each eye was copied into the transparent film. The images were acquired when the margin of live image fitted the contour line on the film. The reliability coefficients of the parameters ranged from 59.4% to 98.2% by the rough centration and 89.7% to 98.7% by the the central alignment. The results indicate that centrally aligned image acquisition provide highly reproducible topographic data of optic nerve head.
Optic Disk* ; Optic Nerve* ; Retina*

Spherical neural mass (SNM) is a mass of neural precursors that have been used to generate neuronal cells with advantages of long-term passaging capability with high yield, easy storage, and thawing. In this study, we differentiated neural retinal progenitor cells (RPCs) from human induced pluripotent stem cells (hiPSC)-derived SNMs. RPCs were differentiated from SNMs with a noggin/fibroblast growth factor-basic/Dickkopf-1/Insulin-like growth factor-1/fibroblast growth factor-9 protocol for three weeks. Human RPCs expressed eye field markers (Paired box 6) and early neural retinal markers (Ceh-10 homeodomain containing homolog), but did not photoreceptor marker (Opsin 1 short-wave-sensitive). Reverse transcription polymerase chain reaction revealed that early neural retinal markers (Mammalian achaete-scute complex homolog 1, mouse atonal homolog 5, neurogenic differentiation 1) and retinal fate markers (brain-specific homeobox/POU domain transcription factor 3B and recoverin) were upregulated, while the marker of retinal pigment epithelium (microphthalmia-associated transcription factor) only showed slight upregulation. Human RPCs were transplanted into mouse (adult 8 weeks old C57BL/6) retina. Cells transplanted into the mouse retina matured and expressed markers of mature retinal cells (Opsin 1 short-wave-sensitive) and human nuclei on immunohistochemistry three months after transplantation. Development of RPCs using SNMs may offer a fast and useful method for neural retinal cell differentiation.
Animals ; Cell Differentiation ; Humans* ; Immunohistochemistry ; Induced Pluripotent Stem Cells ; Methods ; Mice ; Neurons ; Photoreceptor Cells, Vertebrate ; Polymerase Chain Reaction ; Retina ; Retinal Pigment Epithelium ; Retinaldehyde* ; Reverse Transcription ; Stem Cells* ; Transcription Factors ; Up-Regulation

OBJECTIVE: To measure macular and peripapillary retinal-nerve-fiber-layer (RNFL) thickness in normal Filipinos using optical coherence tomography (OCT). METHODS: This observational, cross-sectional study included 362 normal eyes of 181 Filipino participants, 16 to 55 years old, who underwent a detailed ophthalmic examination, automated perimetry, and digital image scanning of the macula and the optic disc by OCT. The macula and RNFL thickness were measured using standard protocols. Paired t-test and linear-regression analyses were used to analyze the data. Conclusion: Macular thickness in Filipinos follows the general patterns of age- and gender-related differences among other racial groups. The data also suggest that Filipino RNFL is thinner compared with those of other racial groups.
Human ; Middle Aged ; Adult ; Adolescent ; TOMOGRAPHY ; TOMOGRAPHY, OPTICAL ; TOMOGRAPHY, OPTICAL COHERENCE ; RETINA ; MACULA LUTEA ; FOVEA CENTRALIS