Superior Temporal Retina Research Articles

Study of peripheral blur in retinal electrical activity

Aims/Purpose: The aim of this study was to evaluate changes in peripheral refraction by the use of a contact lens to control the progression of myopia. In addition, the response of electrophysiological activity in different areas of the retina with and without contact lens was also determined.Methods: We recruited 7 myopic individuals (23.71 ± 5.41 years) with refraction up to −4.50D (spherical equivalent), without eye pathologies and surgeries. Visual acuity was recorded, high and low contrast, with the updated refraction and with the Misight 1 Day contact lens. Peripheral refraction measurements were obtained using an open‐field autorefractometer. Multifocal electrophysiology measurements were performed binocularly with and without contact lens, with dilated pupil. Topography and aberrometry values were also recorded.Results: lens, peripheral refractions become significantly more myopic. The change in peripheral refraction induced at 30° Nasal is −0.66D. High Contrast Visual Acuity was always superior to Low Contrast VA in both conditions. The Misight 1 Day contact lens manifests a different behaviour along the anterior surface of the cornea. LC induces a significant increase in high‐order aberrations, especially in comatic aberrations, which increase three times their initial value.Conclusions: Regarding the electrophysiological response of the retina, with the use of the LC Misight 1 Day, it presented a greater implicit time and amplitude of the P1 component, in the superior temporal retina, these differences being statistically significant. The implicit time of the P2 component increased in the temporal retina and in the retinal area delimited by Rings 3, 4 and 5.

Recurrent vitreous opacity caused by intraocular Toxocara larva: a case report and literature review

BackgroundToxocara larva entity has seldom been reported on the surface of the retina. We report on an unusual case of recurrent vitreous opacity caused by intraocular Toxocara larva after vitrectomy.Case presentationA 34-year-old male was referred to our clinic with a 6-month history of decreased visual acuity in the right eye characterized as red, painless, and progressive. Optos fundus photograph showed optic disc elevation with granuloma, and proliferative membrane starting from the optic disc and running towards the superior temporal retina due to the movement of a Toxocara larva, which was covered by the proliferative membrane in the superior temporal retina. Since it adhered closely to the retina, the lesion in the superior temporal retina was not removed to avoid induction of an iatrogenic retinal break and the larva was not found during the first diagnostic pars plana vitrectomy. Intraocular Anti-Toxocara IgG was 45.53U (< 3, enzyme-linked immunosorbent assay (ELISA)), and the Goldmann-Witmer coefficient was 8.55, confirming the diagnosis of ocular toxocariasis. After this operation, visual acuity improved to 20/200. However, vitreous opacity worsened again, and the proliferative membrane expanded around the Toxocara larva three weeks after the operation. Toxocara larva was found and removed in the superior temporal region during the second operation. His visual acuity improved to 20/100, vitreous opacity disappeared, and the retina was stable two months after the second operation.ConclusionIt is advisable to remove suspected Toxocara larva to prevent the reoccurrence of ocular toxocariasis.

CMV retinitis and subsequent acute cystoid macular oedema after treatment with vitreous ganciclovir injection: a case report

BackgroundTo report a very rare acute cystoid macular oedema following ganciclovir injection in patients receiving allogeneic haematopoietic stem cell transplantation.Case presentationA 44-year-old male patient experienced vision loss in his left eye eight months after allogeneic stem cell transplantation. Ophthalmologic examination showed posterior retinopathy with retinal haemorrhage, a yellow necrotic border, and a vascular white sheath involved in the superior temporal retina but not the posterior pole. Cytomegalovirus DNA results in both plasma and ocular fluid were positive. All tests combined with the patient’s medical history suggested that his ocular disease was cytomegalovirus retinitis. Consequently, he received a weekly ganciclovir vitreous injection. The disease was visibly controlled, and the fundus condition improved after the first three treatments. However, the patient had severe vision loss in his left eye and acute cystic oedema in the macula, while the original lesion was stable two hours after the fourth treatment. The macular oedema subsided significantly on the first day. Over the next week, daily OCT findings indicated that the patient's macular oedema gradually subsided and resolved completely by the second week, and his left eye vision partially improved.ConclusionMacular oedema may occur in patients with cytomegalovirus retinitis, but it rarely occurs during treatment. In this case, the patient's macular oedema appeared and resolved quickly. Macular oedema in patients with cytomegalovirus retinitis receiving vitreous cavity injections of ganciclovir needs to be further studied and discussed.

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

PurposeTo 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. MethodsIn 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. ResultsLIP 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. ConclusionsLIP 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.

Non-inverted pedicle internal limiting membrane transposition for large macular holes.

The purpose of this study is to investigate the effectiveness of a new surgical technique of non-inverted pedicle internal limiting membrane (ILM) transposition for the treatment of eyes with large macular hole. This is a retrospective, consecutive, interventional case series. Twelve eyes of 12 consecutive patients who underwent vitrectomy for the treatment of a large macular hole (MH size > 400 µm) were treated. ILM was peeled and left with a pedicle attached to the superior temporal retina. The macular hole was covered by transposition of the pedicle ILM in a non-inverted way. Preoperative and postoperative best-corrected visual acuity (BCVA), SD-OCT image, macular sensitivity by microperimetry, and multifocal electroretinogram (mERG) response were evaluated. All of the patients were followed for more than 3 months. Postoperative OCT examination confirmed 11 of 12 macular hole closed (91.7%). Six macular hole filled with silicone oil closed as early as the next day. The postoperative BCVA significantly increased compared with preoperative BCVA (P = 0.002). The improvement of macular sensitivity within 2° and 8° circle was also statistical significant (P = 0.018 and P = 0.017, respectively). Fixation stability, shown as the percentage of fixation point within the 2° circle and 4° circle, was remarkably improved (P = 0.017 and P = 0.018, respectively). The R1/R2 and R1/R4 ring ratios also increased significantly as compared with that of baseline. These findings indicate that the non-inverted pedicle ILM transposition results in a high incidence of anatomic closure with good visual outcome for the treatment of large macular hole.

Effects of ocular hypertension in the visual system of pigmented mice.

To study the effects of ocular hypertension (OHT) on the visual system of C57BL/6 pigmented mice, the limbal and episcleral veins of the left eye were laser photocoagulated (LP). LP increased the intraocular pressure during the first five days (d), reaching basal values at 7d. To investigate the effect of OHT on the retinal ganglion cell (RGC) retrograde axonal transport, hydroxistilbamidine methanesulfonate (OHSt) was applied to both superior colliculi (SCi) and the retinas were dissected 2 or 4 weeks after LP. To determine RGC survival, these same retinas were immunoreacted against Brn3a (general RGC population) and melanopsin (intrinsically photosensitive RGCs, m+RGCs). To study whether OHT affected non-RGC neurons in the ganglion cell layer (GCL), RGCs were immunodetected with Brn3a and all GCL nuclei counterstained with DAPI in a group of animals examined 4 weeks post-LP. Innervation of the SCi was examined at 10 days, 8 or 14 weeks after LP with the orthogradely transported cholera toxin subunit-B. OHT resulted in diffuse and sectorial loss of OHSt+RGCs (50% at 2 weeks and 62% at 4 weeks) and in a comparable loss of Brn3a+RGCs at the same time intervals. m+RGCs decreased to 59% at 2 weeks and to 46% at 4 weeks, such loss was diffuse, did not parallel the sectorial loss of the general RGC population and was more severe in the superior-temporal retina. In the GCL, cell loss is selective for RGCs and does not affect other non-RGC neurons. The retinotectal innervation appeared significantly reduced at 10 days (55.7%) and did not progress further up to 14 weeks (46.6%). Thus, LP-induced OHT results in retrograde degeneration of RGCs and m+RGCs, as well as in the loss of CTB-labelled retinotectal terminals.

An improved model of light-induced retinal damage for grading standardization in rat

Background Light-induced retinal damage models vary as many influence factors,herein the modeling method is difficult to copy.It is necessary to establish the grading standardization of retinal damage after retinal light exposure.Objective This study was to improve the modeling method and establish a grading standardization for light-induced retinal damage in rat.Methods Twenty-four SPF 8-10 week-old male SD rats were randomly divided into 4 groups and 6 eyes for each group.The rats were exposed to light intense of 5000 lx for 1,2,3 hours respectively in 3 groups,and other 6 rats served as the normal group.Full-field light exposure experiment was performed for each individual rat separately,and an annular illumination box was used tO ensure the experimental rat moving in a single direction and exposing the right eye in 5000 lx light surrounding during experimental duration.Ganzfeid electroretinogram(ERG)was recorded from the experimental rats at the fifth day after light exposure,and the animals were then sacrificed for histopathology observation to evaluate the retinal thickness change.All procedures which involved animals adhered to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research.Results After exposing to intensity light for 1,2,3 hours,the b-wave amplitudes of rod response,maximal mixed response,oscillatory potential in scotopic ERG as well as cone response,20 Hz flicker response of photopic ERG were significant declined as lapse of light exposure time(F=71.690,P=0.000；F=56.250,P=0.000；F=23.610,P=0.000：F=27.130,P=0.000；F=27.030,P=0.000)and lowed by 26.2％,52.5％,70.7％,24.4％,39.3％,58.1％respectively at the end of experiment.Meanwhile,the b-wave latencies of rod response,maximal mixed response in scotopic ERG as well as cone response of photopic ERG were evidently different among different groups (F=1.370,P=0.282；F：0.800,P=0.508；F=11.840,P=0.000；F=2.080,P=0.136).Light induced retinal damage located mainly at the temporal retina area.After intensity light exposure for 1,2,3 hours,the thickness of outer nuclear layer at the superior temporal retina attenuated by 11.3％,25.6％and 72.5％,respectively(P<0.05).A significant difference was seen in mean thickness of outer nuclear layer at superior temporal retina among different groups(F=410.27,P=0.000). Conclusion A standardized grading method for light-induced retinal damage is recommended.The continuous illumination in a intensity of 5000 Ix for 1,2,3 hours can induce the mild,moderate or severe retinal damage respectively at temporal retina. Key words: Rat; Light induced retinal damage; Animal model; Standardization of grading

Detector sensitivity influences blood flow sampling in scanning laser Doppler flowmetry.

To establish the effect of photodiode sensitivity on the DC (brightness) value and the resultant blood flow measurements of retina and rim tissue using a scanning laser Doppler flowmeter (SLDF). The sample consisted of one eye of each of 15 healthy subjects (mean age 27.8 +/- 6.1 years). Using the Heidelberg Retina Flowmeter (HRF), three 10-deg images of the superior temporal retina and three further images of the superior temporal rim were acquired for each of five DC bands: band 1: 30-70; band 2: 70-110; band 3: 110-150; band 4 150-190; band 5: 190-230. Retinal blood volume, flow and velocity were determined for each image using a 10 x 10 pixel square grid located at a predetermined location on the retina and rim for each subject. Following image acquisition, the DC values corresponding to each pre-assigned retinal or rim location were determined. The mean and standard deviation were determined for the blood flow parameters within each DC band for each subject in both locations. Analysis of variance was used to identify significant change in the data as a function of the DC value (P<0.05). Analysis of variance revealed that retinal blood flow measures acquired within DC band 5 resulted in significantly lower measures of blood flow and velocity (P=0.035 and P=0.049 respectively) than at lower DC values. Band 5 values of flow, volume and velocity in the neuroretinal rim were also significantly low (P=0.016, P= 0.003 and P=0.026 respectively). Peak neuroretinal rim blood flow was recorded when the DC value was between 70 and 110. For blood flow measurement at the retina and neuroretinal rim the DC value should not exceed 190. Photodiode sensitivity as indicated by the DC value affects measurements of ocular blood flow using the HRF.

Vascular Lesions in Diabetes Are Distributed Non-Uniformly Within the Retina

Microaneurysms, acellular capillaries and pericyte ghosts are characteristic of diabetic retinopathy, but it is not clear what causes these lesions or whether they are causally related to each other. The distribution of microaneurysms, acellular capillaries and pericyte ghosts has been evaluated in two animal models of diabetic retinopathy, diabetic dogs (n = 25) and galactose-fed dogs (n = 12). After 5 years of diabetes or galactosemia, retinas were divided into four quadrants at the optic disk, prepared by the trypsin-digest method, and the frequency of the lesions compared among the quadrants. Numbers of lesions were expressed relative to area of trypsin-digested retina examined or to total number of capillary cells examined. Microaneurysms and acellular capillaries were not uniformly distributed across the retina in diabetes or in galactosemia, both lesions being significantly (more than two-fold) more prevalent in the superior temporal retina than in the inferior nasal quadrant of retina. In contrast, the distribution of pericyte ghosts in these same eyes was not significantly different between the quadrants. These findings suggest that pericyte loss may not be sufficient to account for the development of microaneurysms and acellular (occluded) capillaries in diabetes, and raise a possibility that the lesions occur by different mechanisms. Currently available hypotheses regarding the pathogenesis of diabetic retinopathy fail to account for regional differences in the distribution of the vascular lesions within the same retina. Local factors within the eye apparently play an important role in the response of the retinal microvasculature to hyperglycemia.

Vascular lesions in diabetes are distributed non-uniformly within the retina

Microaneurysms, acellular capillaries and pericyte ghosts are characteristic of diabetic retinopathy, but it is not clear what causes these lesions or whether they are causally related to each other. The distribution of microaneurysms, acellular capillaries and pericyte ghosts has been evaluated in two animal models of diabetic retinopathy, diabetic dogs (n = 25) and galactose-fed dogs (n = 12). After 5 years of diabetes or galactosemia, retinas were divided into four quadrants at the optic disk, prepared by the trypsin-digest method, and the frequency of the lesions compared among the quadrants. Numbers of lesions were expressed relative to area of trypsin-digested retina examined or to total number of capillary cells examined. Microaneurysms and acellular capillaries were not uniformly distributed across the retina in diabetes or in galactosemia, both lesions being significantly (more than two-fold) more prevalent in the superior temporal retina than in the inferior nasal quadrant of retina. In contrast, the distribution of pericyte ghosts in these same eyes was not significantly different between the quadrants. These findings suggest that pericyte loss may not be sufficient to account for the development of microaneurysms and acellular (occluded) capillaries in diabetes, and raise a possibility that the lesions occur by different mechanisms. Currently available hypotheses regarding the pathogenesis of diabetic retinopathy fail to account for regional differences in the distribution of the vascular lesions within the same retina. Local factors within the eye apparently play an important role in the response of the retinal microvasculature to hyperglycemia.

Extraretinal Cytomegalovirus Infection Following Retinal Reattachment Surgery in a Patient With Acquired Immunodeficiency Syndrome

Cytomegalovirus (CMV) retinitis is the most common opportunistic ocular infection of the acquired immunodeficiency syndrome (AIDS). Cytomegalovirus antigens have been immunohistochemically localized in all layers of the retina, but are rarely found in ocular tissue other than the retina. 1,2 We recently cared for a patient with AIDS and CMV retinitis who developed endophthalmitis following a scleral buckling procedure. Cytomegalovirus was the only pathogen identified on histopathologic examination of the eye and was present in spindle cells and vascular endothelial cells of the organized vitreous. Report of a Case. —A 31-year-old man with AIDS was being treated with intravenous ganciclovir for bilateral CMV retinitis. The patient had been doing well for nearly 3 months, with visual acuities of 20/40 OD and 20/20 OS, when an area of retinal whitening and intraretinal hemorrhage developed in the periphery of the superior temporal retina of the right eye. The dosage of ganciclovir

Meridional differences in temporal response characteristics

It is well established that a large variety of psychophysical factors influence the critical flicker fusion frequency (CFF). Several recent studies have examined the relationship between CFF and retinal location with confounding and contradictory results. The aim of this study was to determine the CFF for a number of stimulus sizes and luminances in an attempt to evaluate the interactive effects of these parameters and the quadrantic variation in temporal sensitivity. Retinal sensitivity gradients were measured along the two major oblique meridians out to an eccentricity of 50 degrees. CFF profiles for the 1.724 and 0.431 degree targets were shown to decrease with increasing eccentricity more rapidly in the inferior nasal quadrant (superior temporal retina). No significant difference between superior and inferior visual field temporal processing was evident.

Distribution of substance P‐like immunoreactive retinal ganglion cells and their pattern of termination in the optic tectum of chick (Gallus gallus)

Substance P-like immunoreactive (SP-LI) neurons were identified within the inner nuclear layer and ganglion cell layer of the chick retina. The SP-LI cells in the inner nuclear layer consisted of several subtypes of neurons, differing in soma size and dendritic arborization. In the ganglion cell layer a population of moderately labelled SP-LI neurons was also present. About 6-9 microns in diameter and spaced 50-80 microns apart, they formed a regular array across the entire retina, with a density of about 400 cells/mm2 in the superior temporal retina, declining to less than 100 cells/mm2 in the peripheral retina. The total number of SP-LI cells in the ganglion cell layer was approximately 75,000. Individual axons could be followed toward the optic nerve head. Lesions near the optic nerve head resulted in axotomy of ganglion cells within a limited portion of the retina. Two days of postaxotomy there were numerous SP-LI swellings in the proximal segments of axotomized axons. SP-LI neurons in the axotomized zone were larger, more numerous, and showed increased staining of their processes. Fourteen days following a retinal lesion, there was depletion of all SP-LI cells in the ganglion cell layer within the axotomized zone, but the SP-LI neurons in the inner nuclear layer were not noticeably affected. Following a localized injection of rhodamine-coupled latex beads into the optic tectum, a population of retinal ganglion cells (RGCs) in the contralateral retina was retrogradely labelled. Many of these cells also exhibited SP-like immunoreactivity. Examination of the optic tectum indicated the presence of SP-LI fibres in laminae 2-13 (nomenclature of Cajal: Histologie du Systeme Nerveux. Vol. 2. Paris: Maloine, '11), with immunoreactive terminal regions present mainly in laminae 2-4, 7, and 9-13. SP-LI cell bodies were found predominantly in laminae 10-12 and 13. Fourteen days following a retinal lesion, SP-LI processes and terminals were depleted from laminae 2 and 3. Immunoreactive cells and processes in the remaining laminae of the optic tectum were not noticeably altered. The present report confirms the existence of SP-LI retinal ganglion cells in the chick retina and demonstrates their contribution to lamina specific SP-LI arborization in the optic tectum.

The topography of ganglion cell production in the cat's retina

The ganglion cells of the cat's retina form several classes distinguishable in terms of soma size, axon diameter, dendritic morphology, physiological properties, and central connections. Labeling with [3H]thymidine shows that the ganglion cells which survive in the adult are produced as several temporally shifted, overlapping waves: medium-sized cells are produced before large cells, whereas the smallest ganglion cells are produced throughout the period of ganglion cell generation (Walsh, C., E. H. Polley, T. L. Hickey, and R. W. Guillery (1983) Nature 302: 611-614). Large cells and medium-sized cells show the same distinctive pattern of production, forming rough spirals around the area centralis. The oldest cells tend to lie superior and nasal to the area centralis, whereas cells in the inferior nasal retina and inferior temporal retina are, in general, progressively younger. Within each retinal quadrant, cells nearer the area centralis tend to be older than cells in the periphery, but there is substantial overlap. The retinal raphe divides the superior temporal quadrant into two zones with different patterns of cell addition. Superior temporal retina near the vertical meridian adds cells only slightly later than superior nasal retina, whereas superior temporal retina near the horizontal meridian adds cells very late, contemporaneously with inferior temporal retina. The broader wave of production of smaller ganglion cells seems to follow this same spiral pattern at its beginning and end. The presence of the area centralis as a nodal point about which ganglion cell production in the retinal quadrants pivots suggests that the area centralis is already an important retinal landmark even at the earliest stages of retinal development. This sequence of ganglion cell production differs markedly from that seen in the retinae of nonmammalian vertebrates, where new ganglion cells are added as concentric rings to the retinal periphery, and also bears no simple relationship to the cat's retinal decussation line. However, it can be related in a straightforward manner to the organization of axons in the cat's optic tract, suggesting that the fiber order in the tract represents a grouping of fibers by age.

Retinotopy in the optic chiasm of chicks and its significance in an undesirable complication of lesioning the supraoptic decussation

Following discrete lesions of the chick retina, the distribution of degenerating retinal ganglion cell axons in the optic chiasm was examined. A feature of particular interest was the dorsal aspect of the optic chiasm which was found to contain fibres originating from the superior temporal retina. The significance of this finding is discussed in relation to possible damage to the optic chiasm resulting as a consequence of sectioning the supraoptic decussation.

The distribution of ganglion cells in the retina of the North American opossum (Didelphis virginiana).

The distribution of ganglion cells in the retina of the opossum was determined from whole-mounted retinae stained with cresyl violet. Isodensity lines were approximately circular with a peak density of 2,000 to 2,700 cells/mm2 in superior temporal retina (area centralis). The total number of retinal ganglion cells was estimated to be 72,000 to 135,000 (mean 101,026) in retinae ranging from 125 to 187 mm2 in total area. Three groups of ganglion cells were distinguished on the basis of soma size and retinal topography. Large cells (24 to 32 micrometer diameter) were fairly evenly distributed across the retina. Medium cells (12 to 23 micrometer diameter) were more numerous in the superior temporal quadrant than in other regions of the retina. Small cells (7 to 11 micrometer diameter) were prominent in all retinal regions, but particularly in nasal and inferior retina. An analysis of topographical differences in soma size distribution suggests that the medium size cells can be further subdivided into small-medium and large-medium groups.

Regional specialization of the chick retina as revealed by the size and density of neurons in the ganglion cell layer.

On the basis of both morphological criteria and survival after ganglion cell axotomy, three populations of cells can be recognized in the ganglion cell layer of the chick retina. These are: 1) Irregularly shaped cells, which are not affected by axotomy and lack Nissl stain. They comprise about 5% of the total cell population and are probably glial cells. 2) Small cells which have a distinctive teardrop-shaped perikarya, stain for Nissl substance, and are not affected by axotomy. They occur with a uniform density of about 4,000 cells/mm2 across the entire retina and comprise 30-35% of the total number of cells in the ganglion cell layer. It is suggested that these cells are displaced amacrine cells. 3) Cells which stain strongly for Nissl substance and disappear after axotomy. These cells comprise 60-65% of the population of cells in this layer. The density of the latter cells varies throughout the retina. A high-density region in the central area extends into the superior-temporal retina. This high-density region corresponds to a position in the lateral visual field extending into the infero-frontal field. The total number of these cells agrees with the reported number of the optic nerve fibres in the chick, (Rager and Rager, '78); therefore they are presumably ganglion cells. The size distribution of the presumptive ganglion cells varies in different parts of the retina. The only previous study of the distribution and size of cells in the ganglion cell layer of the avian retina did not distinguish between ganglion cells and displaced amacrine cells (Binggeli and Paule, '69). The present results are therefore likely to be a more accurate description of the total number of ganglion cells, the regional variations in their density, and the characteristics of their size than previously reported.