The effect of hyaluronidase on ultrasound-measured dispersal of local anaesthetic following sub-Tenon injection.

PURPOSE: To determine by B-scan ultrasonography if the addition of hyaluronidase affects the dispersal of anaesthetic fluid after sub-Tenon's injection. DESIGN: Single-centre prospective randomised double-blind study. MATERIALS AND METHODS: We performed a trial in 19 patients who were randomised to receive 5 ml of lidocaine 2% alone, or with hyaluronidase 15 IU/ml. A pre-anaesthetic B-scan ultrasound was performed followed by a standard infero-nasal sub-Tenon's injection. Further B-scan ultrasound studies were performed at 1, 3, and 5 min recording depth of local anaesthetic fluid. Data was analysed with Fisher's exact test and Student's t-test where appropriate. Results were considered significant when P<0.05. RESULTS: The maximum depth of local anaesthetic was significantly less in the hyaluronidase group than the control group at 3 and 5 min (0.79 vs1.65 mm, P-value 0.01 and 0.43 vs1.52 mm, P-value 0.002 respectively). There were no statistically significant differences in the akinesia, pain and surgical satisfaction scores between the two groups. CONCLUSIONS: The addition of hyaluronidase significantly augments the dispersal of local anaesthetic fluid, as measured by B-scan ultrasonography.

Neuroblastoma with orbital metastasis: ophthalmic presentation and role of ophthalmologists.

INTRODUCTION: Neuroblastoma is predominantly a tumour of early childhood, which metastasises to the orbits. In such cases, ophthalmologists are involved in the multidisciplinary management. This unique series from a tertiary referral centre is used to elaborate the ophthalmic associations and the ophthalmologist's role in this rare condition. METHODS: A review of case notes was performed on six patients who presented to the paediatric ophthalmology - oncology liaison service at the Leeds teaching hospitals between 1998 and 2003. The ophthalmic outcome and role of the ophthalmologist were assessed. RESULTS: Average age of presentation was 29.8 months (range 15-69 months). Average duration of follow-up was 19.5 months (range 2-58 months). One child died during treatment. Two have completed treatment and are under follow-up. Presenting features of the six children were proptosis in four, periorbital ecchymosis in two, ocular motility restriction in two, and subconjunctival haemorrhage in one. Only one case developed blindness. CONCLUSIONS: The role of the ophthalmologist in patients with metastatic orbital neuroblastoma can vary from a supportive role to one of active intervention and management of ophthalmic complications. The ophthalmologist is involved in diagnosis and staging as well as monitoring response to treatment of both the primary disease and secondary ophthalmic complications.

Do corneal endothelial dystrophies represent ocular neurocristopathies? A discussion on the available evidence.

Current thinking on the embryological origin of human corneal endothelium has it that this cellular population stems from neural crest precursors. There are arguments in support of this assumption but equally persuasive ones against it. We present a discussion of the evidence for and against a neural crest origin for human corneal endothelial cells. In suggesting that caution be applied to extrapolating from non-human work, we would question the fallibility of the current thinking on this subject. To denote human corneal dystrophies as neurocristopathies may be a premature assumption.

Carbon monoxide poisoning causes optic neuropathy.

PURPOSE: To describe the electrophysiological and psychophysical effects of carbon monoxide (CO) poisoning on visual function. METHODS: Three patients are presented who suffered CO poisoning, two due to suicide attempts and one in the course of a road traffic accident. After a full ocular examination, Goldmann visual fields, flash and pattern visual evoked potentials (VEPs) and flash and pattern electroretinograms (ERGs) were tested. RESULTS: Electrophysiology showed reduced or absent N95 components of the pattern ERG and delayed, reduced VEPs. A positive-negative-positive (PNP) VEP waveform was seen in two cases. In one case, where presentation occurred at an early stage, visual and electrophysiological function was improved with hydroxycobalamine. CONCLUSIONS: The combination of ERG and VEP findings suggest that CO poisoning can cause a toxic optic neuropathy that may have a similar aetiological mechanism to that in tobacco amblyopia. Early treatment with hydroxycobalamine may be of some benefit.

Posterior scleritis and polymyalgia rheumatica.

Scleritis is typically a non-infectious granulomatous inflammatory process. It may be found in conjunction with systemic disease, more commonly in those patients with necrotising anterior scleritis. We describe a patient with posterior scleritis and polymyalgia rhematica. This association has not previously been reported.

Spatial diversity in the mid-Flandrian vegetation history of North Gill, North Yorkshire.

The results of investigating a series of 11 pollen and stratigraphic profiles in peats along a 350 m stream section are described. Each profile has a small pollen catchment overlapping little with its neighbour's and the diagrams therefore show fine spatial resolution of the vegetational history. Fine temporal resolution is provided by 1 cm, or for certain sections 1 mm, interval samples. There is evidence that during the Mesolithic distinct patches of the local forest vegetation, of the order of tens rather than hundreds of metres in diameter, were managed by burning and the regular lopping of branches, for periods of up to a few hundred years each. Peat inception is thought to have occurred as early as the 9th millenium BP in some parts of the stream and up to 3000 yr later in others. Lopping and burning was the immediate cause at most sites within the channel of the gill, although fine-scale topographic and geological variation affected the timing. The developing peat was bordered by an alder carr in the lower and middle reaches of the stream. Radiocarbon dating of the mid-Flandrian Ulmus decline shows it to be asynchronous. It was caused by a combination of factors including disease and the affect the mesolithic management practices had had on the soil earlier in the Flandrian.

Two pollen diagrams from the same site.

Two pollen diagrams from within one metre of each other at a blanket peat site on the North York Moors are similar, and fully justify the usual practice of preparing only one diagram. There are however minor differences. These indicate the degree of random variation that can occur and should be borne in mind when interpreting pollen diagrams from blanket peat.