Parinaud's syndrome - A rare presentation of clinically isolated syndrome.

We present a 26 year old Pakistani lady with first presentation of a demyelinating event, presenting as Parinaud's syndrome. The video demonstrates a convergence-retraction nystagmus on upgaze and failure of accommodation, and her brain imaging confirms a corresponding pre-tectal contrast enhancing T2 hyperintense lesion suggestive of demyelination. A review of the literature is presented.

Causes and outcomes for patients presenting with diplopia to an eye casualty department.

PURPOSE: To evaluate the causes and outcomes for patients presenting with diplopia to an eye casualty department. METHODS: Patients presenting with diplopia as a principal symptom, who were referred to the Orthoptic Department from Moorfields Eye Casualty over a 12-month period, were retrospectively investigated. RESULTS: One hundred and seventy-one patients were identified with complete records in 165 cases. There were 99 men and 66 women with an age range of 5-88 years. Monocular diplopia accounted for 19 cases (11.5%), whereas 146 patients (88.5%) had binocular diplopia. Cranial nerve palsies were the most common cause of binocular diplopia accounting for 98 (67%) of cases. Isolated sixth nerve palsy was the largest diagnostic group (n=45). Microvascular disease (hypertension or diabetes mellitus, or both) was present in 59% of patients with cranial nerve palsies, and of this group, 87% resolved spontaneously by 5 months rising to 95% by 12 months. CONCLUSION: Patients with clinically isolated single cranial nerve palsies associated with diabetes or hypertension are likely to recover spontaneously within 5 months and initially require observation only. However, patients with unexplained binocular diplopia and those who progress or fail to recover should be investigated to establish the underlying aetiology and managed as appropriate.

The natural history of Vigabatrin associated visual field defects in patients electing to continue their medication.

PURPOSE: To determine the natural history of visual field defects in a group of patients known to have Vigabatrin-associated changes who elected to continue the medication because of good seizure control. METHODS: All patients taking Vigabatrin alone or in combination with other antiepileptic drugs for at least 5 years (range 5-12 years) were entered into a visual surveillance programme. Patients were followed up at 6-monthly intervals for not less than 18 months (range 18-43 months). In all, 16 patients with unequivocal defects continued the medication. Following already published methodology (Eye 2002; 16;567-571) monocular mean radial degrees (MRDs) to the I/4e isopter on Goldmann perimetry was calculated for the right eye at the time of discovery of a visual field defect and again after not less than 18 months follow-up. RESULTS: Mean right eye MRD at presentation was 36.98 degrees (range 22.25-51.0), compared to 38.40 degrees (range 22.5-49.75) after follow-up; P=0.338 unpaired t-test. Only one patient demonstrated a deterioration in visual field during the study period and discontinued treatment. CONCLUSION: Established visual field defects presumed to be due to Vigabatrin therapy did not usually progress in spite of continuing use of the medication. These data give support to the hypothesis that the pathogenesis of Vigabatrin-associated visual field defects may be an idiosyncratic adverse drug reaction rather than dose-dependent toxicity.

Optic nerve disorders: role of canal and nerve sheath decompression surgery.

Optic nerve sheath decompression (ONSD) maintains a role in the management of visual loss complicating papilloedema in selected patients primarily with idiopathic intracranial hypertension. The evidence base for this intervention is reviewed and audit data on visual outcomes for patients with acute, chronic, and atrophic forms of papilloedema are contrasted. Optic canal decompression has a role in the management of compressive optic neuropathies complicating mass lesions arising from paranasal sinuses and intracranially and can be achieved by transethmoidal, transbasal, and open craniotomy routes. The evidence base supporting this intervention in traumatic optic neuropathy and in primary bone disease causing canal stenosis (in particular fibrous dysplasia) is reviewed where the indications are more controversial.

Vestibular perception in patients with acquired ophthalmoplegia.

Using a perceptual technique it is shown that patients with chronic external ophthalmoplegia have shortened vestibular responses. It is postulated that this is secondary to the retinal image slip experienced by these patients during head movements and a useful compensatory mechanism to suppress motion-induced sickness and spatial disorientation.

Vigabatrin associated visual field loss: a clinical audit to study prevalence, drug history and effects of drug withdrawal.

PURPOSE: To survey clinical visual function including quantitative manual perimetry results in a group of patients taking vigabatrin; to assess the severity of any field defects; to tabulate cumulative and daily doses of medication and to assess possible changes in visual function over time. METHOD: A prevalence study of 100 out of 183 patients currently attending a tertiary referral epilepsy centre who were taking or had recently discontinued vigabatrin (duration 83-3570 days; mean 1885 days) as part of combination anticonvulsant therapy. Complete neuro-ophthalmic examination including Goldmann kinetic perimetry was performed and monocular mean radial degrees (MRD) to the I/4e isopter calculated. Patients were followed up at 6-monthly intervals for not less than 18 months. RESULTS: Acuity and colour vision remained stable in all patients regardless of changes in visual fields. Twenty per cent of patients had significant constriction of their visual field defined as a monocular MRD of 30 degrees or less. Males were significantly more likely to be severely affected than females (P < 0.01). Twenty one patients were followed after discontinuing vigabatrin treatment. Only three of these showed a change in MRD of 10 degrees or more with two deteriorating and one improving. No correlation between treatment duration or cumulative dosage/kg and the severity of defects could be demonstrated. CONCLUSIONS: Earlier reports of a high prevalence of both moderate and more serious field defects were confirmed in patients taking vigabatrin but not in epileptic patients taking other anti-convulsants. We found no evidence of progression or resolution of visual field defects on discontinuing the drug, and no relationship between dose history and visual deficit field loss. An idiosyncratic drug reaction within the neurosensory retina may underlie the pathogenesis of the visual field loss in some patients.

Elevated visual motion detection thresholds in adults with acquired ophthalmoplegia.

AIMS: To test the hypothesis that in patients with acquired chronic bilateral ophthalmoplegia, abnormal retinal image slippage during head movements would result in abnormal thresholds for visual perception of motion. METHODS: Five patients (two males and three females) with ophthalmoplegia were included in the study. The average age was 44 years (range 30-69 years). The aetiology of ophthalmoplegia was myasthenia gravis (MG; n=2), chronic progressive external ophthalmoplegia (CPEO; n=2), and chronic idiopathic orbital inflammation. Visual motion detection thresholds were assessed using horizontal and vertical gratings (spatial frequency) set at thresholds for visibility. The grating was then accelerated at 0.09 deg/s(2). The subject's task was to detect the drift direction of the stimulus. RESULTS: Visual motion detection thresholds were raised to a mean of 0.434 deg/s (SD 0.09) (mean normal value 0.287 deg/s (SD 0.08)) for horizontal motion; and to a mean of 0.425 deg/s (SD 0.1) (mean normal value 0.252 deg/s (SD 0.08)) for vertical motion. The difference in values for both horizontal and vertical motion detection were statistically significant when compared with age matched controls; p <0.023 for horizontal motion and p<0.07 for vertical motion (two tailed t test). CONCLUSION: Abnormally raised visual motion thresholds were found in patients with ophthalmoplegia. This may represent a centrally mediated adaptive mechanism to ignore excessive retinal slip and thus avoid oscillopsia during head movements.

Isolated familial hypomagnesaemia with novel neurological features: causal link or chance concurrence?

We report a patient with isolated familial hypomagnesaemia with hypocalciuria, a rare congenital disorder of magnesium metabolism. During adolescence the patient developed neurological and ophthalmological features not hitherto reported in this condition, including seizures, myoclonus, and retinal pigmentary degeneration. These suggested the phenotype of mitochondrial disease, which has been occasionally reported in association with hypomagnesaemia, but subsequent investigations of mitochondrial function were normal. The pathogenesis of this unusual neurological and ophthalmological syndrome therefore remains uncertain.

Dissociated effects of botulinum toxin chemodenervation on ocular deviation and saccade dynamics in chronic lateral rectus palsy.

AIM: Changes in saccade velocity/amplitude characteristics (main sequence) and attenuation of distance esotropia in response to botulinum toxin (BTX-A) chemodenervation of the antagonist medial rectus were studied in a group of nine patients with chronic lateral rectus palsy. METHODS: Serial measurements of ocular deviation and infrared oculograms of saccadic eye movements to targets at 5 degrees-20 degrees of lateral gaze were made before injection and at 2, 4, 8, 16, and 20 weeks after injection. RESULTS: At 2 weeks after injection, the ocular deviation changed by a mean of 34.5 prism dioptres and the 5 degrees and 10 degrees adduction saccades were significantly slowed (p < 0.02 Wilcoxon signed rank test). By the second examination, however, the adducting saccade peak velocity had returned to normal while the mean ocular deviation remained significantly changed (p = 0.01 Wilcoxon matched pairs). By 20 weeks the mean ocular deviation was not significantly different from that before injection (p = 0.14 matched pairs). CONCLUSIONS: The ocular realignment caused by BTX-A may persist after saccadic function has been restored. This may be because toxin may have a more profound and long lasting effect on the orbital singly innervated fibres which are active tonically at rest to hold gaze whereas there is relative sparing of the additional motor units recruited during fast eye movements.

Reduced duration of a visual motion aftereffect in congenital nystagmus.

Congenital nystagmus (CN) is a primarily horizontal, involuntary, conjugate eye movement which can be observed soon after birth or during the first half-year of life. Individuals with CN rarely complain of oscillopsia. Using a motion aftereffect (MAE), we investigated if individuals with CN have abnormalities in motion perception and if any such abnormality could be due to nystagmus or to compensatory mechanisms to avoid oscillopsia. In task A, patients (n=10) and control subjects (n=10) indicated the direction, duration and relative velocity of MAEs. The subjects binocularly viewed a high contrast, grey scale grating (0.23 cyc/deg; visual angle: 18.3 deg) moving upward or downward at 1, 3, and 6 deg/sec for 60 sec. Vertical optokinetic nystagmus (OKN) was monitored. In task B, patients (n=8) and control subjects (n=8) viewed similar spatial frequency gratings (visual angle: 40.7 degs; 0.5, 0.2, 0.08 cyc/deg) which moved at 4, 10, and 16 deg/sec for 60 sec. In task C, five control subjects, with induced vestibular nystagmus, viewed a grating (0.2 cyc/deg; visual acuity: 28.5 deg), moving upward for 40 sec. In all three tasks, after adaptation with the moving grating, subjects viewed the then static grating and reported the duration and direction of the MAE. One CN patient and eight control subjects reported MABs at all three test velocities in task A. When patients exhibited OKN, the gain was close to one, as in the control group. In task B, seven of the eight patients and all of the control subjects had MABs at the faster adaptation velocities. CN patients had less MAEs at an adaptation velocity of 4 deg/sec and when MAEs were observed, the duration of the illusory motion was reduced by approximately 48%. Control subjects, with induced vestibular nystagmus, reported MAEs at 4 deg/sec (task C). These findings indicate that nystagmus cannot be the only factor accounting for the suppression of motion perception and suggest that compensatory mechanisms used to avoid oscillopsia contribute to the differences found between the groups.

The spectrum of eye disease in children with AIDS due to vertically transmitted HIV disease: clinical findings, virology and recommendations for surveillance.

BACKGROUND: Eye disease in children infected with HIV is uncommon, but there is little information on which children require screening or surveillance and the management of those with retinitis. METHODS: We examined 12 children with symptomatic HIV disease (of a cohort of 98 HIV-positive children) using indirect ophthalmoscopy. When retinitis was found it was documented photographically at the time of diagnosis and on follow-up. RESULTS: Four cases of infective retinitis were diagnosed: three with probable cytomegalovirus retinitis and one with progressive outer retinal necrosis. CONCLUSION: Detection of reactivation is difficult and we recommend fundus photography under general anaesthesia wherever possible. Children with other end-organ disease, symptomatic eye disease and advanced HIV disease with severe immunosuppression require ophthalmological surveillance.