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Biomedical subjects

S Lessell

Publications and source records attributed to S Lessell.

At least 37 records · Page 2Linked to original sources
PubMed1998

Radiation-associated cerebral blindness.

PURPOSE: To report a case of blindness caused by a white-matter injury after whole brain irradiation for metastatic renal cell carcinoma. METHODS: Case report. We performed comprehensive serial neuro-ophthalmologic examinations. RESULTS: Four to 5 months after resection of renal cell metastasis in the left occipital cortex, interleukin-2 therapy, and whole brain irradiation with 3,000 cGy plus a 1,500-cGy boost to the posterior third of the brain, the patient developed a progressive decline in visual acuity in both eyes to hand motions. Magnetic resonance imaging disclosed signal abnormalities without mass effect in the white matter of the parietal and occipital lobes bilaterally, including the optic radiations. CONCLUSION: This case is a unique example of cortical blindness secondary to radiation injury in the occipital lobes and optic radiations.

Blindness↗
PubMed1998

Nutritional amblyopia.

A review was conducted to examine the characteristics and pathogenesis of nutritional amblyopia. Published cases of amblyopia among malnourished allied prisoners of the Japanese during World War II and among Cubans malnourished during the recent economic embargo were analyzed. The picture of nutritional amblyopia derived from these publications is somewhat at variance with the conventional image of the disease. Surprising features include premonitory keratopathy, rapid onset of visual loss, a high incidence of hearing loss, and the presence of peripapillary retinopathy in some cases. No single causative factor can be identified. Genetic susceptibility rarely, if ever, plays a role. Vitamin deficiency may not be important. Protein deficiency, antioxidant deficiency, physical labor, and tobacco smoking are likely to contribute to the occurrence of amblyopia.

Amblyopia↗
PubMed1997

Optic nerve avulsion.

OBJECTIVE: To characterize the presentation, role of diagnostic imaging, and course in patients with optic nerve avulsion. METHODS: A retrospective review of medical records of all 6 patients with optic nerve avulsion who were seen at the Massachusetts Eye and Ear Infirmary, Boston, from January 1, 1991, to July 31, 1995. RESULTS: The initial visual acuity ranged from 20/100 to no light perception. All 6 patients underwent neuroimaging, including computed tomography, magnetic resonance imaging, or both. B-scan ultrasonography was performed on 4 patients, and the condition of 1 patient was evaluated with color Doppler ultrasonography to assess the optic nerve vasculature. In 1 patient, a computed tomographic scan was suggestive of an optic nerve avulsion. Neuroimaging in the other 5 patients, including 2 patients who underwent magnetic resonance imaging, failed to demonstrate an avulsion. During a follow-up period of up to 25 months, 4 patients showed no improvement in visual acuity, 1 patient improved from no light perception to bare light perception, and 1 patient improved from 20/100 to 20/25. CONCLUSIONS: These data suggest that final visual outcome was dependent on initial postinjury visual acuity. Neuroimaging, B-scans, and Doppler ultrasonography were usually not helpful in establishing the presence of optic nerve avulsion, although they may be useful in evaluating comorbid conditions.

Adolescent↗
PubMed1997

Does optic disc appearance distinguish ischemic optic neuropathy from optic neuritis?

OBJECTIVE: To determine whether characteristics of optic nerve swelling assist in distinguishing between optic neuritis and anterior ischemic optic neuropathy. METHOD: Optic nerve stereophotograph review by masked observers. RESULTS: Altitudinal swelling, pallor, arterial attenuation, and hemorrhage are found more commonly in anterior ischemic optic neuropathy than in optic neuritis. CONCLUSION: Optic disc appearance does help to distinguish anterior ischemic optic neuropathy from optic neuritis, although there are overlapping features.

Acute Disease↗
PubMed1997

Recurrent branch retinal infarcts in association with migraine.

Migraine has been blamed for a variety of temporary and permanent visual complications. We describe the case of a young woman with migraine who suffered recurrent episodes of retinal infarction, one of which occurred during an attack of migraine. The infarctions resulted from occlusions of branches of the central retinal artery. Extensive laboratory and radiological investigations failed to establish a nonmigrainous etiology. In some individuals, migraine may cause or promote branch retinal vaso-occlusion and infarction.

Adult↗
PubMed1997

Anterior visual pathway gliomas.

The benign anterior visual pathway glioma undoubtedly is the most controversial subject in neuro-ophthalmology. Although we are persuaded by the evidence that they are true neoplasms rather than hamartomas, the controversy over their biological nature seems moot, as they have a low growth potential. That is not to say that serious visual loss is not common or that, in some cases (especially among those lesions arising in the chiasmalhypothalamic region), tumor-related death and disability cannot occur. These posteriorly located lesions may cause hydrocephalus, and shunting is required if that occurs. The need for shunting in such cases may be the only point on which experts agree. What has yet to be established is whether any of the forms of therapy now available for anterior visual pathway gliomas without hydrocephalus is better than no treatment. Surgery, radiation, and chemotherapy all carry risks. A randomized, controlled study, if feasible, would be apt to settle the issue. The low incidence of these tumors might frustrate attempts to complete such an investigation in a reasonable period. A team of physicians should manage patients with benign anterior visual pathway gliomas. Radiologists, neurologists, neurosurgeons, radiation oncologists, pediatricians, endocrinologists, and oncologists all have a role, but the neuro-ophthalmologist should be the leader. Neuro-ophthalmologists are in the unique position of being able to recognize and document changes in the patient's visual function. Furthermore, neuro-ophthalmologists, being disinterested, are free to choose without bias from among the various management options. The malignant anterior visual pathway glioma is not a subject of controversy. The clinical features at presentation are apt to be misinterpreted as evidence of an inflammatory or ischemic neuropathy rather than the announcement of a fatal brain tumor. Though these patients receive radiotherapy and chemotherapy, these measures have not improved survival significantly, and the outcome is uniformly fatal. The only positive thing that can be said about the malignant gliomas of the anterior visual pathway is that they are so rare.

Adolescent↗
PubMed1997

Cataract in tuberous sclerosis.

We evaluated two patients with tuberous sclerosis (TS) and cataracts. In one, the cataract had been noted at an early age. In the second, it was noted at her first ophthalmic examination, age 31. Review of the literature indicates that although in some cases, cataract is attributable to local ocular disease, it may be a rare manifestation of TS.

Adult↗
PubMed1996

Spontaneous visual improvement in orbital apex tumors.

OBJECTIVE: To describe patients with orbital apex masses involving the optic nerve who enjoyed spontaneous improvement in visual function without therapy. METHODS: A retrospective chart review of cases in an academic neuro-ophthalmology practice identified three cases of tumorous compression of the optic nerve in which there was spontaneous improvement in visual function. Each patient had undergone a full neuro-ophthalmologic evaluation, followed up with serial imaging. RESULTS: The first patient initially had a visual acuity of 2/200 and central visual field defects. Over a 4-year period, her visual acuity improved to 20/40 and her visual field expanded centrally. The second patient initially had a visual acuity of 20/40 and a cecocentral visual field defect. After a 4-year follow-up, her visual acuity had improved to 20/15 and her cecocentral defect had shrunk. The third patient had an initial visual acuity of 20/25, an afferent pupillary defect, and optic atrophy. Over a 2-year period she developed a paracentral scotoma and her visual acuity worsened to 20/30. In the next 2 years her visual acuity improved to 20/10 and her visual field normalized. CONCLUSIONS: In exceptional instances, visual dysfunction from tumorous compression of the optic nerve in the orbital apex may spontaneously improve. Clinicians who use the natural history of visual loss in differential diagnosis should be aware that spontaneous remission is compatible with the presence of tumor.

Female↗
PubMed1996

Neural network differentiation of optic neuritis and anterior ischaemic optic neuropathy.

AIMS: The efficacy of an artificial intelligence technique, neural network analysis, was examined in differentiating two optic neuropathies with overlapping clinical profiles-idiopathic optic neuritis (ON) and non-arteritic anterior ischaemic optic neuropathy (AION). METHODS: A neural network was trained with data from 116 patients with 'gold standard' diagnoses of ON or AION. It was then tested with data from 128 patients with presumed ON or AION, and the correlation of the network's diagnosis with that of expert clinicians tabulated. RESULTS: The network agreed with the clinicians on 97.8% (88 of 90) of the patients with presumed ON and 94.7% (36 of 38) of the patients with presumed AION. Youth, female sex, better initial acuity, a central scotoma, subsequent improvement in acuity, or progressive disease biased the network towards a diagnosis of ON, while advanced age, male sex, presence of hypertension, poor initial acuity, an altitudinal field defect, disc oedema, or less improvement in acuity biased the network towards a diagnosis of AION. CONCLUSION: Neural network analysis is a useful technique for classification of optic neuropathies, particularly where there is overlap of clinical findings.

Adult↗
PubMed1996

Hemifield slide diplopia from altitudinal visual field defects.

We report two cases in which heteronymous, altitudinal visual field defects resulted in loss of fusion and transient overlap of preserved hemifields. This phenomenon resulted in complaints of diplopia similar to that described as "hemifield" slide previously described by temporal hemianopsias. These cases illustrate that generalized loss of fusion, and not the particular type of hemianopic field defect, is responsible for the symptoms known as hemifield slide.

Aged↗
PubMed1995

Quantitative analysis of optic disc cupping in compressive optic neuropathy.

PURPOSE: Cupping of the optic disc, a characteristic sign of glaucoma, has been anecdotally described in association with compressive optic neuropathy. The aim of this study is to perform a masked, controlled, and quantitative measurement of the optic disc cup to determine if compressive lesions of the afferent visual pathway were associated with increased cupping. METHODS: The ratio of cup area:disc area of 29 patients with intracranial lesions impinging on the optic nerves and the chiasm (14 with pituitary adenomas, 7 with meningiomas, 6 with craniopharyngiomas, and 2 with aneurysms) was compared with those of 20 age-matched control subjects. The areal ratios were derived planimetrically from hand-drawn images of magnified stereophotographs. Patients were divided into three groups based on the degree of laterality of visual compromise. Uninvolved eyes served as an internal control for patients with unilateral disease. RESULTS: The median ratio of cup area:disc area was 0.37 for all eyes with visual compromise (n = 51) and 0.10 for control eyes, which was statistically significant (P = 0.0001). The median intereye difference in the ratio of cup area:disc area was 0.13 for patients with unilateral lesions and 0.04 for control subjects. This difference also was statistically significant (P = 0.0001). CONCLUSIONS: The finding of intereye asymmetry in patients with unilateral optic nerve compression is convincing evidence that the enlarged cup is an acquired feature. Several types of compressive lesions of the anterior visual pathway can be associated with increased cupping of the optic disc in the absence of increased intraocular pressure.

Adolescent↗