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Biomedical subjects

N R Miller

Publications and source records attributed to N R Miller.

At least 19 recordsLinked to original sources
PubMed1992

Ophthalmic involvement in myo-neuro-gastrointestinal encephalopathy syndrome.

We studied the clinical, histopathologic, neuroradiologic, biochemical, and genetic profile of a patient with the myo-neuro-gastrointestinal encephalopathy syndrome, a recently described multisystem mitochondriopathy characterized by blepharoptosis and ophthalmoparesis. The patient had severe intestinal pseudo-obstruction and a mixed demyelinating and axonal neuropathy. Abnormal collections of mitochondria in nerve and muscle as well as diffuse white matter disease were present. Cytochrome oxidase activity in muscle mitochondria was reduced. No mitochondrial DNA deletions were detected.

Adult↗
PubMed1992

A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis. The Optic Neuritis Study Group.

BACKGROUND AND METHODS: The use of corticosteroids to treat optic neuritis is controversial. At 15 clinical centers, we randomly assigned 457 patients with acute optic neuritis to receive oral prednisone (1 mg per kilogram of body weight per day) for 14 days; intravenous methylprednisolone (1 g per day) for 3 days, followed by oral prednisone (1 mg per kilogram per day) for 11 days; or oral placebo for 14 days. Visual function was assessed over a six-month follow-up period. RESULTS: Visual function recovered faster in the group receiving intravenous methylprednisolone than in the placebo group; this was particularly true for the reversal of visual-field defects (P = 0.0001). Although the differences between the groups decreased with time, at six months the group that received intravenous methylprednisolone still had slightly better visual fields (P = 0.054), contrast sensitivity (P = 0.026), and color vision (P = 0.033) but not better visual acuity (P = 0.66). The outcome in the oral-prednisone group did not differ from that in the placebo group. In addition, the rate of new episodes of optic neuritis in either eye was higher in the group receiving oral prednisone, but not the group receiving intravenous methylprednisolone, than in the placebo group (relative risk for oral prednisone vs. placebo, 1.79; 95 percent confidence interval, 1.08 to 2.95). CONCLUSIONS: Intravenous methylprednisolone followed by oral prednisone speeds the recovery of visual loss due to optic neuritis and results in slightly better vision at six months. Oral prednisone alone, as prescribed in this study, is an ineffective treatment and increases the risk of new episodes of optic neuritis.

Acute Disease↗
PubMed1992

Leber's hereditary optic neuropathy. Clinical manifestations of the 3460 mutation.

Leber's hereditary optic neuropathy is associated with three different point mutations of mitochondrial DNA that appear to be pathogenetic for the disease. These mutations affect nucleotide positions 3460, 11,778, and 15,257. We reviewed the clinical characteristics of 12 visually symptomatic patients from nine families with the 3460 mutation and compared them with previously published characteristics of symptomatic patients with the 11,778 mutation. The patients with the 3460 mutation were similar to the patients with the 11,778 mutation in most clinical parameters. However, the patients with the 3460 mutation had a higher incidence of visual recovery (20% vs 4%, P = .001), a higher percentage of pedigrees with more than one affected family member (78% vs 43%, P = .011), and a greater frequency of tobacco and alcohol abuse. The difference in visual prognosis between these two mutations and the need for modification of possible risk factors provide added significance to genetic testing for Leber's hereditary optic neuropathy.

Adolescent↗
PubMed1992

Diagnosis of cavernous sinus arteriovenous fistula by measurement of ocular pulse amplitude.

BACKGROUND: The ocular pulse amplitude (OPA), the difference between the maximum and minimum intraocular pressure (IOP) during the cardiac cycle, has been reported to be elevated in the eye ipsilateral to a cavernous sinus arteriovenous fistula. METHODS: The OPA was measured with a pneumotonometer in three groups of patients. Patients in group 1 had no orbital disease (n = 50), patients in group 2 had either unilateral or asymmetric orbital disease (n = 30), and patients in group 3 had angiographically proven cavernous sinus arteriovenous fistulas (n = 15). RESULTS: Patients in group 3 had a higher OPA than patients in either group 1 (P less than 0.001) or group 2 (P less than 0.001). The difference in OPA between an individual's eyes (delta OPA) also was higher in patients with cavernous sinus arteriovenous fistulas than in patients without fistulas (P less than 0.0001). CONCLUSION: A delta OPA of more than 1.6 mmHg was 100% sensitive and 93% specific in identifying patients with cavernous sinus arteriovenous fistulas. There was no difference in delta OPA between direct and dural cavernous sinus arteriovenous fistulas. Successful transvascular embolization of the cavernous sinus arteriovenous fistula normalized the delta OPA by reducing the OPA on the affected side.

Adult↗
PubMed1992

Visual recovery in patients with Leber's hereditary optic neuropathy and the 11778 mutation.

Five patients with Leber's hereditary optic neuropathy (LHON) and the 11778 mitochondrial mutation spontaneously recovered 20/40 or better visual acuity in at least one eye after months to years of legal blindness. The patients ranged in age from 9 to 45 years, and the duration of visual loss before recovery ranged from several months to 5.9 years. These patients constitute only about 4% of the 136 affected LHON patients we have studied who also had the 11778 mutation in their mitochondrial DNA. Thus, even though the visual prognosis for most patients with LHON and the 11778 mutation is poor, a few individuals do recover near-normal vision in at least one eye even years after the initial visual loss.

Adolescent↗
PubMed1991

Late recovery of function after oculomotor nerve palsy.

We studied three patients who developed oculomotor nerve paresis from different causes. Each patient improved somewhat over several months, after which there was no further improvement for at least six months. Although the pareses were thought to be stable after the period of no improvement, each patient subsequently had further improvement in both motility and alignment with resolution of diplopia in primary position and in more than one of the cardinal positions of gaze. Patients with oculomotor nerve paresis may improve further after an initial period of improvement followed by several months of stability.

Adenoma↗
PubMed1991

Clinically detectable nerve fiber atrophy precedes the onset of glaucomatous field loss.

Standardized perimetry and nerve fiber layer and color fundus photography were performed annually on 1344 eyes with elevated intraocular pressures. In 83 eyes, glaucomatous field defects developed that met rigid criteria on manual kinetic and suprathreshold static perimetry. Individual nerve fiber layer photographs were read by two masked observers. The more sensitive of the two identified nerve fiber layer defects in 88% of readable photographs at the time field loss first occurred; 60% (6/10) of eyes already had nerve fiber layer defects 6 years before field loss. In contrast, the nerve fiber layer was considered abnormal in only 11% (3/27) of normal eyes and 26% (84/327) of hypertensive eyes. The location of nerve fiber layer and field defects closely corresponded, but nerve fiber layer loss was generally more widespread. Examiner experience and severity of optic nerve damage influenced results. Mild focal defects were more readily recognized than more severe diffuse atrophy. Nerve fiber layer defects expanded with time, often by the development and coalescence of adjacent areas of damage.

Adult↗
PubMed1991

Optic nerve head and nerve fiber layer in Alzheimer's disease.

We compared (1) the differences in the retinal nerve fiber layer between 26 patients with Alzheimer's disease and 30 age- and race-matched normal controls with use of blue-light high-resolution photography, (2) the differences in disc pallor between 30 patients with Alzheimer's disease and 32 controls with use of a boundary-tracking program and fundus photographs, and (3) the topographic disc variables between 26 patients with Alzheimer's disease and 36 controls with use of an optic nerve head analyzer. A higher proportion of patients with Alzheimer's disease had detectable nerve fiber damage as seen by red-free photography compared with controls. Although the pallor area-to-disc area ratio was not significantly different between patients with Alzheimer's disease and controls, the patients with higher pallor area-to-disc area ratios had higher Alzheimer's Disease Assessment Scale (ADAS) scores and longer durations of disease. Patients had an increased cup-to-disc ratio and cup volume and decreased disc rim area compared with controls. These variables also correlated significantly with ADAS scores and the duration of disease. The correlation among the optic nerve head changes and the ADAS scores in patients with Alzheimer's disease suggests a potential role for optic nerve head analysis in monitoring the progression of Alzheimer's disease and in assessing the effectiveness of any treatments developed.

Aged↗
PubMed1991

Retinochoroidal (optociliary) shunt veins, blindness and optic atrophy: a non-specific sign of chronic optic nerve compression.

Fifteen patients are described in whom the triad of blindness, optic disc swelling followed by optic atrophy, and optociliary shunt veins occurred. The causes of the syndrome included spheno-orbital meningioma, optic nerve glioma, meningocele of the optic nerve, and chronic papilloedema. It is postulated that chronic compression of the intraorbital portion of the optic nerve produces gradual obstruction of the central retinal vein, thus preventing the normal passage of venous blood from the retina through the central retinal vein to the cavernous sinus. Optociliary veins are a pre-existing shunt system that allows retinal venous blood to bypass the central retinal vein and exit from the orbit via the choroidal circulation and its anastomoses.

Adolescent↗
PubMed1991

Visual parameters in patients with pituitary adenoma before and after transsphenoidal surgery.

Eighty-two patients with pituitary adenoma who underwent transsphenoidal surgery were examined before and after surgery. Nineteen patients had a normal preoperative neuro-ophthalmological examination. All of these patients maintained normal visual parameters postoperatively. The remaining 63 patients had tumour-related loss of visual acuity, visual field, or both. These patients ranged in age from 18 to 78 years. Duration of symptoms ranged from one day to ten years, with a median of six months. Preoperative visual acuity was 6/12 or better in 72% of eyes, with 90% of patients having 6/12 or better in their better eye. Only 7% of eyes had a normal preoperative visual field. Both visual acuity and visual field improved postoperatively in the majority of eyes. In eyes that were examined within one week after surgery and subsequently, substantial improvement occurred within the first postoperative week, but further improvement continued over weeks to months postoperatively, with visual field taking longer to stabilise than visual acuity. Visual acuity at last examination was 6/12 or better in 87% of eyes, and visual field at last examination was normal in 50% of eyes. A total of 92% of patients had visual acuity of 6/12 or better in their better eye, and 62% of patients had a normal visual field in their better eye. Visual acuity at last examination was correlated with both age and preoperative visual acuity. Last visual field also was correlated with both age and preoperative visual field. Patients with preoperative optic atrophy had a poorer visual prognosis than did patients with normal fundi.

Adenoma↗
PubMed1991

The effect of age and initial visual acuity on the systemic and visual prognosis of central retinal vein occlusion.

Papillophlebitis is the term that is often used to describe a central retinal vein occlusion with preserved visual acuity in a young, healthy patient. Among 194 patients with a diagnosis of central retinal vein occlusion (CRVO), 19 patients were identified who were under 50 years of age and who had visual acuity of 6/12 or better in the affected eye. These patients retained good vision in the affected eye during the course of the disorder with 17 eyes returning to 6/6. All of these patients remained healthy over a mean follow-up period of about four years. This group of patients was compared to a second group of 28 patients who also were under 50 years of age, but who had initial visual acuity in the affected eye less than 6/12. These patients had a variable visual outcome. In addition, they had a higher prevalence of systemic hypertension over the follow-up period than did a group of age-matched control subjects. An additional comparison was made to a group of 26 patients with visual acuity of 6/12 or better in the affected eye but who were over 50 years of age. Forty-six per cent of these patients had final visual acuity less than 6/12, and they had a higher prevalence of systemic vascular disease than did a group of age-matched control subjects.

Adult↗
PubMed1991

Fourth nerve paresis and ipsilateral relative afferent pupillary defect without visual sensory disturbance. A sign of contralateral dorsal midbrain disease.

We describe a patient with a left trochlear nerve paresis and a left relative afferent pupillary defect despite normal visual acuity, color vision, visual fields, and fundus examination. Magnetic resonance imaging revealed a lesion in the right dorsal midbrain extending from the brachium of the superior colliculus to the inferior colliculus. The anatomy and physiology of the pupillary light reflex are reviewed, as are possible mechanisms for the laterality of afferent pupillary defects with midbrain lesions. The presence of a trochlear nerve paresis with an ipsilateral relative afferent pupillary defect and an otherwise normal ophthalmic exam indicates a lesion in the contralateral dorsocaudal midbrain.

Adult↗