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Biomedical subjects

A B Safran

Publications and source records attributed to A B Safran.

At least 19 recordsLinked to original sources
PubMed1996

Multiple evanescent white dot syndrome after hepatitis B vaccine.

PURPOSE: Hepatitis B vaccine has become an effective means of preventing complications of hepatitis B. However, it occasionally induces serious side effects. We report a case of multiple evanescent white dot syndrome (MEWDS) that occurred following hepatitis B vaccination. METHODS: A 23-year-old woman with a one-week history of progressive loss of vision in the left eye and bilateral photopsia was referred for examination. Her symptoms appeared 24 hours after a booster intramuscular injection of hepatitis B vaccine. RESULTS: Clinical examination, fluorescein angiography, and the course of events were typical of MEWDS. CONCLUSIONS: This case demonstrates the occasional occurrence of MEWDS after hepatitis B vaccine and suggests that hepatitis B virus immunization may be a risk factor for this retinal condition.

Adult↗
PubMed1996

Feasibility of automated visual field examination in children between 5 and 8 years of age.

AIMS: To investigate how young children develop the ability to undergo a visual field evaluation using regular automated perimetry. METHODS: The study included 42 normal girls aged 5, 6, 7, and 8 years. Twelve locations in the 15 degrees eccentricity were tested in one eye, using an Octopus 2000R perimeter with a two level strategy. False positive and false negative catch trials were presented. The examination was performed three times in succession. Before the examination procedure, a specially designed programme was conducted for progressive familiarisation. RESULTS: During the familiarisation procedure, it was found that all of the 5-year-old children, seven of the 6-year-old children, and three of the 7-year-old children were unable to perform immediately, and correctly, the instructions given during the familiarisation phase; these children took from 30 seconds to 3 minutes to comply with the examiner's requests. With the exception of one 5-year-old child, all tested subjects completed the planned procedure. The mean proportion of false negative answers in catch trials was 1.6%. The mean proportion of false positive answers was 12.2%. The quadratic dependency on age suggested by the averages was not significant (F(3,116) = 0.88; p = 0.45). Detection stimulus improved with age, as shown by the fact that probability of perceiving dim stimulus increases significantly (F(3,116) = 12.68; p < 0.0001). CONCLUSION: Children did remarkably well regarding both the duration of the examination and the reliability of the answers. A preliminary familiarisation phase with a specially designed adaptation programme was found to be mandatory with children aged 7 or under. To our knowledge, this is the first time that such an investigation has been performed.

Age Factors↗
PubMed1996

Diplopia from skew deviation in unilateral peripheral vestibular lesions.

Vertical diplopia from skew deviation is well described in brainstem lesions. The phenomenon can also result from peripheral vestibular lesions. During the past years, we have observed these ocular changes in the acute stage following unilateral vestibular neurectomy and labyrinthectomy (n = 13), as well as in series of patients suffering from idiopathic sudden unilateral peripheral vestibular or cochleo-vestibular deficit (n = 5). Diplopia from skew deviation was noted immediately following ablative vestibular procedures; in patients with idiopathic vestibular deficit, it was observed as an associated sign. In all patients, clinical evaluation revealed an acute unilateral peripheral vestibular loss, with spontaneous nystagmus toward the unaffected ear and absence of nystagmic response to caloric testing on the affected ear. Skew deviation was measured using the Hess-Weiss test, which is based on the haploscopic principle. Static visual vertical was evaluated with the original methods of vertical frame and Maddox rod techniques. Photographs were made of the ocular fundi, to measure the degree of cyclotorsion of both eyes. In our patients, we found skew deviation with hypotropia of the eye that was ipsilateral to the affected ear and conjugated cyclotorsion and tilt of the static visual vertical on the side of the affected ear. Skew deviation was the first sign to disappear within a few days; conjugated cyclotorsion and tilt of the static visual vertical persisted for weeks to months. The eye-head postural reaction, consisting of head tilt, conjugated eye cyclotorsion, skew deviation, and alteration of vertical perception directed toward the side of the lesion, is known as the Ocular Tilt Reaction (OTR). The mechanism is presumably related to a lesion of the otolithic organs and/or to changes in the afferent graviceptive pathways. In man, the OTR is often mild and unrecognized, masked by spontaneous nystagmus and marked neuro-vegetative symptoms. Our observations indicate that skew deviation, as a part of the OTR, occurs in patients with sudden peripheral vestibular lesions, whether surgical or non-surgical in origin.

Adult↗
PubMed1995

Role of the completion phenomenon in the evaluation of Amsler grid results.

PURPOSE: To evaluate the limitations, particularly those related to the perceptual completion phenomenon, of Amsler grid tests in patients with central scotomas caused by macular disorders. METHODS: We tested 15 affected eyes of 15 patients with macular lesions. In each subject, the central visual field was assessed by using four different types of Amsler grid testing and a tangent screen. Tests were conducted in a random order, and the sequence of tests was repeated once. The distance between the fixation point and the closet border of the plotted scotoma was assessed. For each patient, reproducibility in repeated examinations was evaluated by assessing changes in location of the computed center of the defects and by measuring changes in the position of the center of the scotoma. RESULTS: The tangent screen was more sensitive than Amsler grids in delineating the borders of the scotoma, and the results were more reproducible. Furthermore, by using a tangent screen, the fixation point was found adjacent to the scotoma. CONCLUSION: Poor sensitivity and intraindividual variations found with Amsler grid testing are at least partly a result of the perceptual completion phenomenon. This phenomenon proved to be a dynamic and fluctuating process, as the results of two successive Amsler grid tests were not comparable, even when the technique was identical and the time between tests was no more than two to 15 minutes.

Aged↗
PubMed1995

[Vestibular neuritis: a frequently unrecognized cause of diplopia].

The vestibular function plays an essential role in the stabilization of the image on the retina. In addition, when the head is tilted, it contributes to maintain horizontally the plane of the gaze. Vestibular changes can result in oscillopsia and/or diplopia. The latter is related to occurrence of a skew deviation. The authors emphasize the frequent occurrence of diplopia following disorders of the vestibular nerve, specially after vestibular neuritis. In clinical practice, the causal relationship between vestibular neuritis and diplopia is often unrecognized.

Adult↗
PubMed1995

[Automated static perimetry in the child: methodologic and practical problems].

PURPOSE: In a pediatric population, the use of computerized static perimetry is known as particularly difficult. The specific difficulties which may occur when testing young subjects are stability of fixation, ability to maintain concentration, resistance throughout the procedure, and reliability of the answers. It seems important to investigate and to develop appropriate strategies for the examination of children aged 8 years and younger according to their ability to undergo visual field evaluation using automated static perimetry. PATIENTS AND METHODS: Eighty normal children aged 5 to 8 years old were evaluated using an Octopus 2000R perimeter, with a one-level strategy. Adaptation of the procedure were included. RESULTS: The analysis of answers and false-positive catch-trials showed that children as young as five years old did remarkably well regarding both the duration of the examination and the reliability of answers. CONCLUSIONS: Automated static perimetry examination can provide reliable results in children as young as five years old once a familiarization procedure has been conducted and if the duration of examination does not exceed the child's capacity to remain task focused.

Child↗
PubMed1995

Angioscotomata and morphological features of related vessels in automated perimetry.

AIMS: To determine principles which regulate the occurrence of angioscotomata in automated static perimetry, variations in light sensitivity were correlated with the location and diameter of neighbouring retinal vessels. METHODS: Ten normal eyes were tested with the Octopus 2000R, using a 0.431 degree light stimulus. Sensitivity was quantified in points located around the blind spot, according to a regular, 0.5 degree constant, grid pattern. From 336 to 443 locations were tested in each eye. The resulting printouts were superimposed on corresponding fundus photographs. At each tested point, the following five additional variables were evaluated: the diameters of the closest and the second closest vessel (in 0.1 degree units); the distances of the apparent location of the tested point to the closest and the second closest vessel (in 0.25 degree units); and the distance between the two closest vessels (in 0.25 degree units). Altogether, 3869 locations were tested and 23,214 values were quantified. RESULTS: The following two conditions were found to be related to a reduction in sensitivity: (1) proximity (< 0.25 degree) to a large vessel (> or = 0.5 degree in diameter); (2) proximity (< 0.25 degree) to one of two adjacent (< 0.5 degree distant), moderately large vessels (0.3 degree to 0.4 degree in diameter). In condition 1, sensitivity was 51.3% and specificity was 92.2%; in condition 2, sensitivity was 16.2% and specificity was 98.3%; and with a combination of conditions 1 and 2, sensitivity was 67.6% and specificity was 90.5%. Increase by 0.1 degree of an adjacent vessel which was 0.4 degree in diameter markedly affected light sensitivity. CONCLUSION: Modifications in vessel diameter are observed in a number of circumstances, including adaptive vascular response to changes in ambient conditions and obstructive disorders of retinal vessels. These findings indicate that changes in vessel diameter over time can result in fluctuation of sensitivity. It is concluded that, in contrast with what is commonly stated, when ocular media are unaltered and the subject's collaboration is adequate, temporal variations in measured thresholds do not necessarily reflect functional changes in nervous tissues in the visual pathways.

Adult↗
PubMed1994

Skew deviation after vestibular neuritis.

We treated five patients with vestibular neuritis who had strabismus. Three of them spontaneously noted vertical diplopia. During the following weeks and months, strabismus progressively resolved, indicating the recently acquired nature of the oculomotor condition. In three of these individuals, a change in visual vertical and cyclo-torsion of the globes suggested that strabismus was a form of skew deviation that occurred as a part of an ocular tilt reaction resulting from the peripheral vestibular lesion. Strabismus appears to occur frequently in this common vestibular condition.

Adult↗
PubMed1994

[Occlusion of the ophthalmic artery in Crohn disease].

BACKGROUND: Nearly 10% of patients with Crohn's disease develop ocular complications. Most complications are inflammatory in nature, and involve both the anterior and the posterior segments of the eye. Episcleritis, uveitis and keratopathies are the most frequently described. Occlusions of retinal and optic nerve vessel are less common. We believe this to be an important observation as the ocular involvement was the patients primary complaint, thus allowing the correct diagnosis to be made. PATIENT: We report a case of a 44-year-old woman, who presented with an occlusion of the ophthalmic artery, before the diagnose of Crohn's disease was established.

Adult↗
PubMed1994

Anterior ischemic optic neuropathy in Graves' disease.

Optic neuropathy occurred in two patients suffering from Graves' disease with marked limitation of eye movement. Optic nerve changes were moderate. They consisted of parapapillary flame-shaped hemorrhages, swelling of the disc, and bundle defects in the visual field on the involved side. This clinical pattern suggested that the optic neuropathy was anterior and ischemic in nature. In one patient, symptoms of optic neuropathy were noted 3 days after starting stretching exercises with the ocular muscles, performed following a friend's advice in an attempt to prevent increase in restrictive myopathy. In patients with Graves' disease, it is conceivable that mild optic neuropathy occasionally occurs as a result of elevation in intraocular pressure, and stretching exercises of the ocular muscles might consequently favor such ischemic events. In the mechanisms of optic nerve involvement associated with Graves' disease, the role of ischemia should be considered in addition to the widely accepted role of optic nerve compression by enlarged extraocular muscles, at the level of the orbital apex.

Female↗
PubMed1993

Topical timolol maleate might adversely affect serum lipoproteins.

Conflicting observations have been reported about the effects of topically administered timolol maleate on serum lipoproteins. We therefore considered this issue in a series of eight glaucoma patients receiving timolol maleate. Cholesterol and triglycerides were measured in plasma and in low-density lipoproteins (LDL), and high-density lipoproteins (HDL), both before and following three months of treatment. Following the treatment, the mean atherogenic index was increased from 2.72 to 3.38 (p = 0.012). This suggests that the atherogenic index should be determined before and during timolol maleate treatment in high-risk cardiovascular patients.

Administration, Topical↗
PubMed1993

[Clinical evaluation of otolithic function by the measurement of ocular cyclotorsion and skew deviation].

The ocular tilt reaction (OTR) consists in an association of an eye-head postural reaction, alteration of vertical perception, conjugated eye cyclotorsion, skew deviation and head tilt. We observed this condition following unilateral vestibular neurectomy and labyrinthectomy performed in patients suffering from severe Meniere's disease. All patients described postoperative vertical diplopia and vertical perception tilt. One illustrative case is reported in detail here. Changes in visual vertical were measured using a vertical frame with a pivoting pointer and the Maddox rod calibrated with a spirit level. The actual eye torsion was measured by a photography of eye-fundus. In the follow-up, it was found that vertical diplopia disappeared within a few days while conjugated eye cyclotorsion lasted weeks to months. Mechanisms involved in the OTR could be the consequence of a unilateral deafferentation of the utricular and saccular organs. We feel that the techniques of examination which we used with this patient might be a useful measurement for the clinical evaluation of unilateral otolithic dysfunction.

Adult↗
PubMed1992

Increasing short-term fluctuation by increasing the intensity of the fixation aid during perimetry.

An increase in short-term fluctuation is a clinically useful clue in the diagnosis of acquired disorders of the visual pathways. However, short-term fluctuation can also be increased in normal subjects by several factors. We found an increase in short-term fluctuation occurred in normal subjects when the visual field was tested using a bright fixation aid. Eight normal subjects underwent automated perimetry with the Octopus 2000R, in which the dimmest (12.5 candelas/m2) and brightest (435 cd/m2) available fixation aids were used. Mean short-term fluctuation values were 1.63 +/- 0.27 dB with the dimmest aid, and were 2.65 +/- 1.26 dB with the brightest aid. The difference was significant using the paired t-test (P = .037). Moreover, mean sensitivity was reduced from 35.67 +/- 2.26 dB to 33.66 +/- 1.71 dB when the brightest fixation aid was used (P = .004). In six of eight subjects, the relative changes in short-term fluctuation after an increase in brightness of the fixation aid were more pronounced than those in mean sensitivity. An increase in intensity of the fixation aid may cause visual changes in normal subjects that resemble those induced by disorders in the visual pathways. Whenever possible, minimal intensity of the fixation aid should be used to allow for an adequate interpretation of short-term fluctuation values.

Adult↗