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PubMed1981

Hyperornithinaemia and gyrate atrophy of the retina: improvement of vision during treatment with a low-arginine diet.

A 15-year-old patient with hyperornithinaemia (0.6--1.2 mmol/l) and gyrate atrophy of the retina was given a low-arginine diet to reduce plasma ornithine to a concentration (0.15--0.25 mmol/l) near the normal range. After five weeks of treatment, there was improvement in the visual function of one eye which had been severely impaired without improvement for 3 years. This improved visual function was maintained until compliance with the diet deteriorated at eight months, after which visual function regressed towards pretreatment status. Overrestriction of dietary arginine produced hyperammonaemia, indicating that arginine is an essential aminoacid in ornithine transaminase deficiency. These results suggest that reduction of plasma ornithine may reverse a metabolic neuroretinopathy in this disease, and offer hope that progression of the retinal atrophy can be arrested as well.

Adolescent↗

PubMed1994

Autosomal dominant retinitis pigmentosa in a large family: a clinical and molecular genetic study.

PURPOSE: To characterize the pedigree, visual function phenotype, and responsible mutation in a large family with autosomal dominant retinitis pigmentosa. METHODS: Pedigree data were obtained by personal interviews and corroborated with community records. One hundred twenty-eight members of the family were examined clinically, and a subset of 12 affected subjects was further studied with dark- and light-adapted static perimetry and electroretinography. The coding region of the rhodopsin gene was polymerase chain reaction (PCR) amplified and resolved by denaturing gradient gel electrophoresis. Genomic DNA samples from nine affected and five unaffected family members were analyzed by PCR amplification and restriction enzyme digestion. RESULTS: A 14-generation pedigree was identified in which retinitis pigmentosa (RP) was inherited in an autosomal dominant fashion. Affected individuals reported early night blindness and showed vessel attenuation and bone spicule-like pigmentary changes. In these individuals, the rod electroretinogram (ERG) was not detectable, and the cone ERG was reduced in amplitude and delayed in timing. With dark-adapted perimetry, rod function could be detected in only one young patient, and it was markedly abnormal. Light-adapted perimetry indicated that cone sensitivity could be relatively well preserved in the central field, but it was diminished in the periphery even in the most mildly affected subjects. A valine345-to-leucine mutation was identified in the rhodopsin gene and shown to cosegregate in the heterozygous condition with the disease. CONCLUSIONS: The natural history of RP in this family begins with a loss of rod function, progresses to involve the cone system, and leads eventually to a severe loss of visual function. The invariance of valine345 in all functional vertebrate visual pigments sequenced to date, and the unusually conservative nature of the valine345-to-leucine mutation suggests that the carboxy terminus of rhodopsin is involved in a highly specific interaction with one or more rod proteins.

Adolescent↗

PubMed1993

Human visual cortical function during photic stimulation monitoring by means of near-infrared spectroscopy.

Near-infrared spectroscopy (NIRS) was used to monitor human visual cortical function during and after photic stimulation (PS) in five adult volunteers. Cerebral blood volume (CBV) increased on the occipital surface during PS, but NIRS parameters did not change on the frontal surface. The increase in CBV was caused by a rapid increase in oxyhemoglobin with but a small increase in deoxyhemoglobin, suggesting cerebral vascular dilatation with decreased oxygen consumption. After PS stopped, CBV promptly decreased and then slightly increased again. Cytochrome aa3 did not show any change during and after PS. These phenomena reappeared following repeated PS in all five subjects. These results may represent the first step in the development of NIRS imaging.

Adult↗

PubMed1988

[Abnormalities of retinal function (light sense) following idiopathic central serous chorioretinopathy and diffuse retinal epitheliopathy].

Although central serous retinopathy is considered a "benign" condition, it is associated in healed forms with frequent and troublesome impairment of visual function. The abnormalities are even more severe after diffuse retinal pigment epitheliopathy. Since Snellen visual acuity testing is a relatively imprecise index of visual function, it does not enable the subtle visual disturbances experienced by these patients to be fully appreciated. The authors evaluated visual function disorders by static automated perimetry and contrast sensitivity in 30 patients with healed central serous retinopathy and in five patients with diffuse epitheliopathy at a cicatricial stage. The results of this study are examined and discussed.

Adult↗

PubMed1985

Clinical and physiological basis for a new method underlying rehabilitation of the damaged visual nerve function by direct electric stimulation.

A new method of rehabilitation of damaged visual nerves has been tested during clinical physiological investigations in 45 patients with pathological opticochiasmal brain tumor, inflammation and trauma. The essence of the new method was in implanting the electrode into the nerve when the patient was operated on for the pathological formation and in directly stimulating the nerves for 2 or 3 postoperational weeks. Effectiveness of electrical stimulation was increased by direct recording of the electroneurogram as well as by the results of ophthalmological observations. Considerable improvement of vision was observed in 75%, and in 25% of these cases the vision was found to actually normalize. Even in cases of total blindness, vision was partially rehabilitated in 8 of 10 cases. Direct electrophysiological investigation of the visual nerve potentials enabled us to objectively estimate their functional state, predict the probability of visual rehabilitation as well as increase the efficiency of therapy. Neurophysiological mechanisms of visual rehabilitation under the influence of electrical stimulation of the visual nerves are discussed.

Adolescent↗

PubMedDate not supplied

Visual acuity after successful treatment of large macular retinoblastoma.

Recent trends in the treatment of retinoblastoma have favored radiation therapy as opposed to enucleation. A major determining factor in selecting radiation therapy is the possibility of useful posttreatment visual function. While the treatment of nonmacular tumors seems reasonable, little information is available about the posttreatment visual outcome of large posterior pole tumors. We treated 17 patients (20 eyes) with group III-V retinoblastoma and large posterior pole tumors with external beam radiation. Visual acuity after treatment ranged from 5/200 to 20/50. Potential posttreatment visual function was difficult to predict using such pretreatment factors as age at diagnosis, funduscopic appearance, and the number, size, and location of the tumors. Surprising visual function was obtained in some patients with multiple large macular tumors. Follow up ranged from 1 to 8 years. No patient developed metastatic disease; however, four patients required subsequent cataract extraction. This study supports the consideration of radiation therapy as the primary treatment in eyes previously felt to have a poor visual outcome.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

[Experience with Ramipril (Triatec(R)) in the treatment of glaucomatous neuropathy].

PURPOSE: The main purpose of this study was to assess the improvement in visual function in patients with glaucomatous neuropathy treated with Ramipril (angiotensin-converting enzyme inhibitor); we were thus able to link ischemia and visual deterioration in glaucoma. Ramipril increases endothelium-dependent relaxation and vasodilatation to bradykinin via B2 receptors linked to the formation of nitric oxide (NO). On the other hand, Ramipril could have an influence on retinal neurotransmission modulation. MATERIALS AND METHODS: Ramipril was administered to 22 patients suffering from chronic glaucoma in whom intraocular pressure (IOP) was controlled by classic treatment, combining Ramipril with this treatment. It was given orally (1.25mg daily) for 3 months in order to improve visual function. In addition to the standard follow-up (visual acuity, intraocular pressure, automatic perimetry, optic disk), this study focused on the systemic tolerance to Ramipril. RESULTS: Thirty eyes in 22 patients were evaluated. Mean intraocular pressure did not change, but the mean visual acuity improved from 0.53 to 0.74. After 3 months of treatment, the perimetric test (Octopus) showed an improvement in the mean defect (MD) (48%) and the corrected loss variance (CLV) (54%). No complications in terms of arterial pressure were observed. CONCLUSION: This study has shown that Ramipril was an effective agent in glaucomatous neuropathy. It improved visual function without changing IOP and had a satisfactory general tolerance in all patients. This could be explained in part by a higher production of NO by endothelial cells. This gas is a powerful vasodilator. It is formed from L-arginine by constitutive nitric oxide synthetase. This would provide an improvement in local blood flow autoregulation altered in glaucoma by an endothelial dysfunction.

Aged↗

PubMed2006

Impact of severity and bilaterality of visual impairment on health-related quality of life.

OBJECTIVE: To assess the impact of unilateral and bilateral visual impairment (VI) and its severity on health-related quality of life (HRQOL) in Latinos 40 years and older. DESIGN: A cross-sectional population-based study, the Los Angeles Latino Eye Study (LALES). PARTICIPANTS: Five thousand three hundred seventy-seven LALES participants. METHODS: Health-related quality of life was measured by the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and the Medical Outcomes Study 12-Item Short Form Health Survey (SF-12). Visual acuity (VA) was measured by a standardized protocol. Based on the presenting VA, VI was classified as unilateral or bilateral impairment and as either mild (20/40-20/63) or moderate/severe (20/80 or worse). MAIN OUTCOME MEASURES: National Eye Institute VFQ-25 and SF-12 composite and subscale scores. RESULTS: The NEI VFQ mean composite score decreased from no VI (86) to bilateral moderate/severe VI (66) (P<0.006). Relative to participants with no VI, those with unilateral or bilateral VI at any severity level had significantly lower NEI VFQ-25 scores for 10 of the 12 subscales (P<0.05). The largest mean score differences between participants with and without VI were observed for subscales related to driving difficulties (42.5 points), vision-related dependency (29.1 points), distance vision (27.0 points), and vision-related mental health (24.5 points). No differences in SF-12 scores were found between participants with and without VI (P>0.05). CONCLUSION: Relative to persons with no VI, persons with bilateral mild and unilateral or bilateral moderate/severe VI report greater difficulties in performing most vision-dependent daily activities and experience vision-related dependency and poorer vision-related mental health. Because most visual function subscale scores were significantly lower in persons with bilateral mild and/or unilateral/bilateral moderate/severe VI, health care providers should consider intervention in these persons. Our findings provide further insight into the relationship between severity level, bilaterality of VI, and self-reported visual function. These data can be used to refine the determination of visual disability in persons with VI.

Adult↗

PubMed1999

Priming of visual and functional knowledge on a semantic classification task.

Several lines of evidence suggest that semantic memory may be organized according to domain-specific attributes (e.g., visual or functional). Repetition priming both within and across these semantic knowledge domains was measured in 4 experiments to determine whether retrieval of one attribute can occur independently of retrieval of other attributes. The authors found a strong same-attribute priming advantage that persisted even when the classification task differed between study and test. Also evident was a small but consistent cross-attribute priming effect. Cross-attribute priming was not affected by changes in the modality of the test item, suggesting that the effect reflects the repetition of conceptual, and not perceptual, processes. On the basis of these results, the authors suggest that conceptual priming reflects the recapitulation of both domain-specific and nonspecific semantic processing.

Adult↗

PubMed1997

Creating connected representations of cortical gray matter for functional MRI visualization.

We describe a system that is being used to segment gray matter from magnetic resonance imaging (MRI) and to create connected cortical representations for functional MRI visualization (fMRI). The method exploits knowledge of the anatomy of the cortex and incorporates structural constraints into the segmentation. First, the white matter and cerebral spinal fluid (CSF) regions in the MR volume are segmented using a novel techniques of posterior anisotropic diffusion. Then, the user selects the cortical white matter component of interest, and its structure is verified by checking for cavities and handles. After this, a connected representation of the gray matter is created by a constrained growing-out from the white matter boundary. Because the connectivity is computed, the segmentation can be used as input to several methods of visualizing the spatial pattern of cortical activity within gray matter. In our case, the connected representation of gray matter is used to create a flattened representation of the cortex. Then, fMRI measurements are overlaid on the flattened representation, yielding a representation of the volumetric data within a single image. The software is freely available to the research community.

Cerebral Cortex↗

PubMed1991

Treatment of pseudotumor cerebri by primary and secondary optic nerve sheath decompression.

We performed optic nerve sheath decompression in 53 patients (101 eyes) with pseudotumor cerebri and visual loss. Sixty-nine eyes (85 patients) with acute papilledema uniformly had improved visual function after optic nerve sheath decompression. Of 32 eyes with chronic papilledema (18 patients), only ten had improved visual function after optic nerve sheath decompression. This difference was significant (P = .0001). Thirteen eyes required secondary or tertiary optic nerve sheath decompression after an initial successful result. Eleven of 13 eyes had improved visual function after repeat optic nerve sheath decompression. We believe that patients with acute papilledema and visual loss should be offered optic nerve sheath decompression, and if symptoms recur, repeat optic nerve sheath decompression is a safe and effective treatment option.

Acute Disease↗

PubMed1992

Aberrant retinal projections to midbrain targets mediate spared visual orienting function in hamsters with neonatal lesions of superior colliculus.

Rodents, cats, and most nonmammalian vertebrates with bilateral tectal deafferentation or ablation in adulthood are extremely deficient at orienting to visual stimuli; yet animals with neonatal lesions of superficial layers of the superior colliculus (SC) show partial sparing of this response, particularly for targets in the central visual field. In this study, we sought to determine whether these spared orienting abilities are mediated by aberrant retinal projections to the remaining intermediate layers of the SC, or whether visual cortex (VC) mechanisms or alternative behavioral strategies are responsible. Neonatal golden hamsters received either bilateral heat lesions of the SC (rlSC), or a heat lesion of the right SC and enucleation of the right eye (rSCrE). This latter procedure causes axons from the left eye to recross the tectal midline and terminate in the "wrong" (left) SC (Schneider 1973). As adults, both groups of hamsters were extremely deficient in visually guided approach to stationary targets, although rlSC-lesioned hamsters showed some sparing for central field targets and rSCrE-lesioned hamsters often made wrong-direction turns for targets in the left peripheral field. We then subjected both groups of neonatally lesioned hamsters to bilateral aspiration lesions of the VC. Retesting showed no change in visual orienting behavior as a result of the cortical lesions. Labeling of the optic tract with horseradish peroxidase (HRP) revealed abundant aberrant retinal projections to remaining intermediate layers of the SC and thalamic nucleus lateralis posterior (LP), as well as supernormal innervation of pretectal nuclei, the dorsal terminal nucleus of the accessory optic tract, and the ventral nucleus of the lateral geniculate body (LGv). We conclude that the spared visual orienting capabilities of hamsters with rlSC and rSCrE lesions are mediated by the aberrant midbrain projections, and that cortical mechanisms are not involved in spared visual orienting functions following these neonatal lesions.

Animals↗

PubMed1981

[Follow-up of retrobulbar neuritis with the octopus computer perimeter (author's transl)].

Methodological possibilities of quantifying the visual field course in retrobulbar neuritis were studied. In nine patients suffering from this condition the visual field had been examined repeatedly using the Octopus computer perimeter (program 31, stimulus size 3). Total loss of sensitivity and the number of test points with pathologic results had been chosen to correlate to recovery of visual function. These parameters, as well as visual acuity, were compared with the cumulative steroid dose. It is concluded that rapid recovery of visual function with initial steroid therapy may have a starter effect for spontaneous further improvement of sensitivity in the central visual field. However, a prospective, controlled clinical trial would be required to provide definite proof of the usefulness of steroid therapy in retrobulbar neuritis.

Follow-Up Studies↗

PubMed1994

Electrophysiology and psychophysics in ocular hypertension and glaucoma: evidence for different pathomechanisms in early glaucoma.

It is not clear whether glaucomatous optic nerve damage is the end result of one pathological process or whether there are several mechanisms by which the final disease is manifest. The use of electrophysiological and psychophysical tests which measure the function of specific subdivisions of the visual pathways have been shown to be of use in the early diagnosis of glaucoma. In addition these results may help to elucidate the mechanisms of loss of visual function in patients with early glaucoma. One hundred and ninety-three patients with ocular hypertension (intraocular pressure > 24 mmHg, with normal visual fields and optic discs), 30 with glaucoma and 35 controls underwent pattern electroretinogram (PERG), peripheral colour contrast thresholds, motion detection thresholds (MDT) and Humphrey automated visual fields at the same visit. For each test there was a significant proportion of patients with abnormal results as has been found in previous studies of these techniques. However, there was a significant lack of correlation between the groups with only a small number of patients having abnormalities on more than one test. Of the patients demonstrating abnormal PERGs, 36% had abnormal colour contrast and 32% abnormal MDT, but only 15% were abnormal on both tests. Early glaucomatous damage may be focal or diffuse in nature. Similarly there may be preferential damage to ganglion cells subserving different visual functions or damage at different retinal layers. The results lend support to these hypotheses and give further evidence that more than one pathomechanism may be involved early in the glaucomatous process.

Color Perception↗

PubMed1996

A role for phospholipid polyunsaturation in modulating membrane protein function.

Visual transduction is one of the best characterized G protein--coupled signalling systems. In addition, about 50% of the disk membrane phospholipid acyl chains are 22:6n-3, making this system ideal for determining the role of polyunsaturation in modulating membrane-signalling systems. The extent of formation of metarhodopsin II (MII), the G protein--activating photointermediate of rhodopsin, was studied in phospholipid vesicles composed of a variety of phosphatidylcholines, differing in their acyl chain composition at the sn-2 position. The amount of MII formed increased progressively with the level of acyl chain unsaturation at the sn-2 position. The effect of added cholesterol was to reduce the amount of MII formed. The acyl chain packing free volume of the rhodopsin containing lipid vesicles was characterized by a fractional volume parameter fv derived from measurements of the time-resolved fluorescence anisotropy decay of the hydrophobic membrane probe 1,6-diphenyl-1,3,5-hexatriene. The relationship among sn-2 acyl chain unsaturation, cholesterol content, and MII formation is explained on the basis of variation in fv with bilayer lipid composition and a novel model for the packing of phospholipids containing polyenoic acyl chains, such as 22:6n-3.

Fats, Unsaturated↗

PubMed1997

A prospective multicenter trial of octreotide in 24 patients with visual defects caused by nonfunctioning and gonadotropin-secreting pituitary adenomas. French Multicenter Octreotide Study Group.

OBJECTIVE: The somatostatin analog octreotide has been demonstrated to improve optic tract compression caused by pituitary macroadenomas within hours of its administration and/or reduce tumor size in some patients. We report the results of a prospective multicenter study of the effects of octreotide on visual function and tumor size in patients with nonfunctioning pituitary adenomas or gonadotropin-secreting adenomas. METHODS: Twenty-four patients with visual defects caused by histologically confirmed macroadenomas were administered octreotide via continuous subcutaneous infusion, as follows: 100 micrograms the 1st day and, if necessary, 200 micrograms the 2nd and then 100 or 200 micrograms three times daily if visual function improved. Vision was assessed after 4 days, 1 month, and 2 months, including tumor size evaluation. Visual improvement was defined by a net gain of at least 2/10 in acuity and/or of more than 20% of the surface of one isopter (a reduction in tumor volume of > or = 20% of the initial measurement); opposite changes were defined as deterioration. RESULTS: Visual improvement was noted in 13 of 24 patients, 10 of 23 patients and 9 of 22 patients, and was not noted in 11 of 24 patients, 14 of 23 patients, and 13 of 22 patients after 4 days, 1 month, and 2 months, respectively. After 2 months, three adenomas had shrunk, three had not changed in size, and one had increased; visual function improved in the seven patients with these adenomas. Octreotide was discontinued in 13 patients for lack of efficacy. CONCLUSION: The incidence of visual improvement and tumor shrinkage noted in this study was higher than previously reported. Our data suggest that early onset of visual improvement might help in deciding which patients profit from octreotide. However, concomitant gain in visual acuity with deterioration in visual fields or visual improvement with an increase (moderate) in tumor size can occur.

Adenoma↗

PubMed2006

Ophthalmological findings in children born after intracytoplasmic sperm injection.

PURPOSE: To investigate visual function and ocular morphology in children born after intracytoplasmic sperm injection (ICSI) and compare them with visual function and ocular morphology in matched children born after spontaneous conception. METHODS: A total of 137 children born after ICSI and 159 control children were examined at the age of 5 years in a blinded study. The two groups were matched for age, gender and maternal age. The children underwent a detailed ophthalmological investigation by an ophthalmologist and an orthoptist. RESULTS: A total of 90.4% of the ICSI children had a visual acuity (VA) in the better eye of >or= 0.8, compared with 93.7% of the controls (NS). No significant differences were found between ICSI children and controls with regard to hyperopia, myopia, astigmatism, heterotropia, stereoscopic vision and convergence. One child with Goldenhar syndrome and one with Marcus Gunn syndrome were observed in the ICSI group. One child in the ICSI group was treated for retinopathy of prematurity. CONCLUSION: In this limited study group, no significant differences in visual function and/or ocular morphology were found between children born after ICSI and matched control children at the age of 5 years.

Case-Control Studies↗

PubMed2006

Neuroplasticity as a double-edged sword: deaf enhancements and dyslexic deficits in motion processing.

We examined the hypothesis that aspects of processing that are most modifiable by experience (i.e., "plastic") display the most vulnerability in developmental disorders and the most compensatory enhancement after sensory deprivation. A large literature reports that motion processing and magnocellular visual function is selectively deficient in dyslexia. A smaller literature reports enhancements in such functions in deaf individuals. However, studies with dyslexic and deaf individuals have used different experimental paradigms to assess visual function, and no research has yet examined both sides of modifiability (i.e., enhancements and deficits) using the same experimental paradigm. In the present research, visual function was compared in dyslexic (n=15), deaf (n=17), and control adults by using automated peripheral kinetic and foveal static perimetry. In the kinetic perimetry task, the dyslexic group showed deficits ( p<.003), whereas the deaf group showed enhancements ( p<.001) for detecting moving light points in the periphery. In the foveal static perimetry task, neither the dyslexic ( p=.866) nor the deaf ( p=.632) group differed significantly from controls in foveal contrast sensitivity thresholds, and no group or individual approached ceiling performance on this task. Taken together, the present data bridge previous literatures and suggest that motion processing tasks are selectively modifiable, either to decrement or enhancement, whereas foveal contrast sensitivity does not differ in dyslexic or deaf groups.

Adult↗