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Biomedical subjects

G A Fishman

Publications and source records attributed to G A Fishman.

At least 163 records · Page 9Linked to original sources
PubMed1984

Autosomal dominant vitreoretinochoroidopathy (ADVIRC).

We report the second family recognised to have autosomal dominant vitreoretinochoroidopathy. The clinical features were (1) autosomal dominant inheritance; (2) peripheral, coarse pigmentary degeneration of the fundus for 360 degrees, with a relatively discrete posterior border in the equatorial region (this finding may be pathognomonic); (3) superficial punctate yellowish-white opacities in the retina; (4) various vascular abnormalities; (5) breakdown of the blood-retinal barrier; (6) retinal neovascularisation; (7) vitreous abnormalities; and (8) choroidal atrophy. Visual reduction was mainly due to macular oedema or vitreous haemorrhage.

Adolescent↗
PubMed1984

Supernormal scotopic ERG in cone dystrophy.

Three patients with a bull's-eye macular lesion and other signs characteristic of cone dystrophy gave an unusual ERG finding. In response to a white flash of moderate intensity the scotopic b-wave amplitude was considerably larger than normal. One patient had elevated rod thresholds and nyctalopia, while the other 2 had normal rod sensitivity associated with the supernormal scotopic b-wave amplitude. In the latter 2 patients the abnormal ERG pattern was unchanged for 4 years and 7 years respectively. This atypical finding, of a supernormal scotopic b-wave amplitude in response to light of moderate intensity, appears to characterise a subgroup of patients with cone dystrophy, probably of autosomal recessive inheritance. The pathogenesis of the abnormal ERG remains uncertain.

Adaptation, Ocular↗
PubMed1984

Acute macular neuroretinopathy: early receptor potential change suggests photoreceptor pathology.

The early receptor potential (ERP) was recorded in a patient with typical fundus findings of unilateral acute macular neuroretinopathy. These amplitudes were compared with those of a normal control population. The ERP amplitude of the affected eye measured 13 months after onset of visual impairment was significantly reduced (4.8 SD) compared with the normal fellow eye. A subsequent ERP measurement 7 months later (20 months after onset) showed the same amount of amplitude reduction, indicating that recovery had not occurred by this time. Since the ERP is generated during photolysis of visual pigment molecules and requires intact photoreceptor outer segment membranes to orient these molecules, our findings suggest that the outer segments are affected in at least some patients with this disorder. A retinal vascular aetiology for this disorder was rejected by studying a subject with a large retinal depression sign that occurred after a previous retinal vascular occlusion.

Action Potentials↗
PubMed1984

Rod-cone interaction in flicker perimetry.

We have assessed the influence of the rod system on cone flicker sensitivity during flicker perimetry. For temporal frequencies above 18 Hz extrafoveal cone-mediated flicker thresholds for a white test stimulus are as much as 1.5 log units lower when measured against a large background light that saturates the rods than when measured in darkness. Following a Ganzfeld bleach extrafoveal cone flicker thresholds are at their minimum once the cones have recovered their sensitivity, but then thresholds rise as the rods begin to recover from the bleach. Our results indicate that the flicker sensitivity of the extrafoveal cone system at high temporal frequencies is influenced by the rods surrounding the flickering test stimulus. The rods reduce flicker sensitivity maximally in the dark adapted state, and their suppressive influence is minimised only by strong rod bleaches or by large backgrounds that saturate the rod system.

Adaptation, Ocular↗
PubMed1984

Prolonged rod dark adaptation in retinitis pigmentosa.

The time course of rod dark adaptation was measured in 12 patients and carriers of retinitis pigmentosa (RP). In contrast to previous studies the rod absolute threshold was determined prior to any exposure to the bleaching light. For seven of the patients and carriers the recovery of rod sensitivity to the prebleach level was prolonged, with the delay ranging from mild to severe. The prolongation appeared to be limited to the late phase of bleaching recovery; the early portion of rod dark adaptation, measured following a weak bleach, was normal. These results suggest a selective impairment in the processes underlying rod dark adaptation in some patients with RP.

Adolescent↗
PubMed1984

Retrospective analysis of 58 children with retinoblastoma.

We performed a retrospective analysis of 58 children with retinoblastoma seen at the University of Illinois at Chicago between 1960 and 1982. Our findings showed an almost equal distribution by sex, a predominance (69%) of white patients, and a common presenting symptom (70%) of leukocoria, with (22%) or without (48%) strabismus. Unilateral involvement was noted in 35 patients (60%). Of the 23 (40%) bilaterally affected children, 19 had simultaneous involvement at the time of diagnosis. All bilateral and 90% of the unilateral cases were diagnosed before age five years. Family history was positive for retinoblastoma in five bilateral and one unilateral case. At the time of diagnosis, 35 patients had stage V disease (Reese-Ellsworth classification, Table 1). Depending on the stage of disease treatment included enucleation, radiation, and chemotherapy. Mortality was 25% from 1960 to 1974, and zero thereafter.

Age Factors↗
PubMed1983

Laser interferometric visual acuity in senile macular degeneration.

Twenty-nine eyes from 15 patients were affected by senile macular degeneration and had clear ocular media. Tests with retinal interference fringe patterns produced by a low-energy helium-neon laser and Snellen's charts showed that in 13 eyes, interferometric and Snellen's acuities were within one line. In the remaining 16 eyes, laser interferometric acuities were notably better than Snellen's acuities. Our results suggest that laser interferometric visual acuities, prior to lens extraction, will prove inconsistent in accurately predicting postoperative Snellen's acuities in patients with senile macular degeneration.

Aging↗
PubMed1983

Usher's syndrome. Ophthalmic and neuro-otologic findings suggesting genetic heterogeneity.

The conditions of 70 patients with Usher's syndrome were studied by ophthalmic and neuro-otologic examinations. Two distinct clinical and presumed genetic types were discernible on the basis of differences in hearing impairment, vestibular sensitivity, and, to a lesser extent, deterioration in retinal photoreceptor function. Distinguishing these two types has relevance for both diagnosis and genetic counseling of patients with Usher's syndrome.

Adolescent↗
PubMed1983

Early receptor potential measurements in human ocular siderosis.

There is electrophysiologic evidence that photoreceptors have normal visual pigment density (outer segment length) at a stage of ocular siderosis when the photoreceptor membrane function is defective. The early receptor potentials (ERPs) from two patients showed normal amplitudes, although the electroretinograms (ERGs) had reduced a- and b-waves for both cone and rod ERG responses. Since the ERP is generated by photolysis of visual pigment and requires orientation of the pigment molecules by outer segment disc membranes, the normal ERP amplitudes suggest that the photoreceptor outer segments have normal photopigment density, are of normal length, and are properly oriented. However, the transduction mechanism that converts visual pigment photolysis into membrane electrical potentials (the ERG a wave) is defective at this stage of ocular siderosis.

Adult↗
PubMed1983

Determination of human cone pigment density difference spectra in spatially resolved regions of the fovea.

A new method was developed to measure spectrally and spatially resolved cone pigment optical density difference in normal human subjects. Using digitized television images of human retinas scanned before and after bleaching the cone pigments with a bright light, unique high-resolution images of cone pigment density difference were produced. The spectral peak density difference within the fovea was found to be at 560 nm. These measurements demonstrate a decrease in cone pigment optical density difference with increased distance from the subject's central fixation point in the fovea. The cone pigment density difference was asymmetrically distributed in the fovea with higher amounts on the nasal side.

Dark Adaptation↗
PubMed1983

Two additional benefits of dark glasses on rod vision in patients with congenital achromatopsia.

The visual performance of nine rod monochromats was measured with photopic stimuli viewed through filters that attenuated the ambient illuminance. In kinetic perimetry experiments, eight of nine patients showed substantially larger visual field size under the experimental as compared to the control conditions. In increment threshold or brightness-matching experiments, long wavelength sensitivity was shown to be enhanced under the experimental conditions.

Adolescent↗
PubMed1983

A genetic analysis of retinitis pigmentosa.

Genetic analysis of 457 patients with retinitis pigmentosa (RP) included categorisation of families by recognised mendelian pattern of inheritance and formal segregation analysis of all informative sibships. Of the 368 probands a surprisingly high 18% (68) had significant congenital loss of hearing and were diagnosed as having Usher syndrome. The RP probands were categorised as: 21.7% autosomal dominant, 9.0% X-linked, 16.0% autosomal recessive, 3.3% genetic type uncertain, and 50.0% simplex. Segregation analysis reflected this high proportion of simplex cases, accounting for reduced penetrance in dominant families; only 20% remain classified as sporadic (possibly nongenetic). In the matings between normal persons estimates of the segregation ratio also indicate lower values than expected. Unlike in RP sibship, segregation in the Usher syndrome is consistent with the hypothesis of recessive inheritance. Therefore RP with significant hearing loss segregates as expected, while even if a proband is classified as a dominant or recessive the recurrence risk for the RP phenotype may be below mendelian expectation.

Female↗
PubMed1983

Comparative electroretinograms in argon laser and xenon arc panretinal photocoagulation.

We performed electroretinograms (ERG) on both eyes of 11 diabetic patients before and one month after panretinal photocoagulation for diabetic retinopathy. Each patient had one eye treated with argon laser and the fellow eye treated with the xenon arc photocoagulator. After photocoagulation the ERG was symmetrically reduced unless the retinal area burned with xenon arc was greater than twice the retinal area burned in the fellow eye by the argon laser photocoagulator.

Adult↗
PubMed1983

Usher's syndrome. CNS defects determined by computed tomography.

Six of the 12 patients with Usher's syndrome, assessed with computed tomography (CT), demonstrated findings of cerebellar atrophy. Of these, three patients also showed occipital lobe atrophy. Continuous rapid rotational CT scans disclosed seven patients with abnormal hindbrain circulation pattern. Our results suggest that central nervous system (CNS) defects may be among the pleiotropic effects of the Usher's syndrome gene.

Adolescent↗
PubMed1982

Visual improvements with red-tinted glasses in a patient with cone dystrophy.

A patient with cone dystrophy empirically discovered that his vision improved when a red filter was placed in front of his eyes. The present study documents the conditions under which his visual acuity and field improved and shows that the patient's vision is mediated by the night vision photoreceptors, the rods. Increment threshold functions examined the benefits (and limitations) of red glasses to the patient's vision.

Adult↗
PubMed1982

Autosomal dominant vitreoretinochoroidopathy.

Autosomal dominant vitreoretinochoroidopathy is a newly described fundus dystrophy characterized by abnormal chorioretinal hypopigmentation and hyperpigmentation, usually lying between the vortex veins and the ora serrata for 360 degrees. In this zone, there are a discrete posterior boundary, preretinal punctate white opacities, retinal arteriolar narrowing and occlusion, and, in some cases, choroidal atrophy. Most affected family members have diffuse retinal vascular incompetence, cystoid macular edema, and presenile cataracts. The vitreous is characterized by fibrillar condensation and a moderate number of cells. Electroretinograms are normal in younger affected individuals and are only moderately abnormal in older ones. Preretinal neovascularization, present in the posterior pole, is progressive in the proband. There are no identifiable systemic or skeletal abnormalities, high myopia, optically empty vitreous, lattice degeneration, areas of white-without-pressure, retinal breaks, or retinal detachment; thus, previously described vitreoretinopathies can be excluded from diagnostic consideration. Progression of this diagnostic seems to be extremely slow in most family members.

Adolescent↗