Laser pointers revisited: a survey of 14 patients attending casualty at the Bristol Eye Hospital.

AIMS: The largest clinical series of laser pointer exposures to date is described, to document any long term visual sequelae and assess objectively the visual threat from transient ocular exposure. METHODS: 14 cases were collected prospectively and triaged by ophthalmic nurses before referral to an ophthalmologist for a complete ophthalmic examination. Regardless of the need for clinical follow up, all patients were contacted by telephone at a mean interval of 10.5 months following exposure to inquire about new or persisting symptoms. RESULTS: 11/14 cases presented within 24 hours of exposure and 5/14 incidents were reported to the police. Reduced acuity in the affected eye compared with the contralateral were documented in 5/14 cases. The commonest physical sign was a punctate epitheliopathy, seen in 5/14 cases, and the commonest symptom was ocular discomfort, reported by 11/14 patients. There were no consistent retinal findings. Follow up by telephone survey revealed that two patients were wearing new glasses, but had not been refracted before the exposure; one had intermittent ocular discomfort; the remaining 11 were asymptomatic. CONCLUSIONS: This study is reassuring to the ophthalmology community and the general public in failing to demonstrate consistent, long term damaging effects of transient ocular exposure to laser pointer beams.

Modulation of glucose transport in fetal rat lung: a sexual dimorphism.

Male fetuses exhibit delayed lung maturation and surfactant production in comparison with female fetuses. This delay may be related to sex hormone effects: estrogen enhances and androgens delay lung development. The uptake of glucose, an important precursor for surfactant synthesis, may be differently affected by estrogen and androgens. In these studies we determined the effects of these two hormones on glucose transport (glucose uptake, glucose transporter [Glut] 1 protein, and mRNA) and hexokinase activity in lung tissue of fetal rats. On Day 20 of gestation (term = 21.5 d) lung tissue was harvested from female and male fetal rats, minced into explants, and cultured for 24 h. Basal glucose uptake, measured in the absence of sex hormones, was 37% higher (P < 0.05) in female compared with male lungs. Explants were washed and cultured for an additional 3 h or 24 h in either estradiol or dihydrotestosterone (DHT) at 0, 1, 10, or 100 nM. Twenty-four-hour treatment with estradiol in both male and female explants increase 2-deoxyglucose uptake, Glut 1 protein, and mRNA levels (P < 0.05). However, explants from male fetuses were not as responsive to estradiol treatment as were those from females (P < 0.05). Treatment for 24 h with DHT decreased 2-deoxyglucose uptake, Glut 1 protein, and mRNA levels in females and males (P < 0.05). There was no difference in response between females and males. Short-term incubation (3 h) with sex hormones had no effect on glucose uptake. However, 3-h treatment with estradiol did increase Glut 1 mRNA levels (P < 0.05). Hexokinase activity was not affected by estradiol or DHT treatment. These findings indicate that estradiol and DHT differentially regulate glucose uptake in fetal rat lung tissue. This regulation of substrate supply (glucose) by estradiol and DHT may be another mechanism for the sexual dimorphism observed in lung development and surfactant synthesis.

Effects of gaseous environment and temperature on the storage behaviour of Listeria monocytogenes on chicken breast meat.

Portions of skinless chicken breast meat (pH 5.8) were inoculated with a strain of Listeria monocytogenes and stored at 1, 6 or 15 degrees C in (1) aerobic conditions; (2) 30% CO2 + air; (3) 30% CO2 + N2; and (4) 100% CO2. When samples were held at 1 degree C the organism failed to grow under any of the test conditions, despite marked differences between treatments in spoilage rate and ultimate microflora. At 6 degrees C counts of L. monocytogenes increased ca 10-fold in aerobic conditions before spoilage of the meat, but only when the inoculum culture was incubated at 1 degree C rather than 37 degrees C. In CO2 atmospheres growth of L. monocytogenes was inhibited on meat held at 6 degrees C, especially under 100% CO2. By contrast, storage at 15 degrees C led to spoilage of the meat within 2 d, in all gaseous environments, and listeria levels increased up to 100-fold. Differences in the behaviour of L. monocytogenes on poultry and red meats are discussed.

Combined electrophysiological assessment of the visual system in central serous retinopathy.

Six subjects suffering from idiopathic central serous retinopathy were examined during the acute phase using a battery of neurophysiological tests. The records (using skin electrodes) included the electro-oculogram (EOG), the white light electroretinogram (ERG) during various stages of dark and light adaptation, and the flash and pattern reversal visual evoked potentials. Results obtained from the affected eye were compared with those from the healthy eye. The values of the healthy eye were not significantly different from our normal control group. The EOGs of the affected eyes were not significantly different from those of the healthy eyes. The 'a' wave of the ERG during light adaptation was significantly (P less than 0.05) smaller in the affected eye. The amplitudes of the other components and the latencies of all components were not affected. The latency of the PR-VEP of the affected eye in all subjects was prolonged in comparison with the unaffected eye. In 3 subjects the latency was prolonged by more than 2 S.D.s compared with our control group. The amplitude of the PR-VEP in 5 of our 6 subjects was slightly but significantly (P less than 0.02) smaller in the affected eye. There was no correlation between amplitude and latency changes.

Indirect choroidal tears and late onset serosanguinous maculopathies.

The retinal changes are described in four patients who acquired indirect choroidal tears and later developed serosanguinous maculopathies. Two subsequently received photocoagulation therapy and two did not. An analysis of previous cases reported in the literature with this condition, combined with our own findings, show that only patients with ruptures close to fixation have been observed to develop late onset haemorrhages and oedema at the macula. Spontaneous resolution with preservation of useful levels of visual function not infrequently occurs, and the indications for photocoagulation therapy are probably limited.

Retinal tumours in neurofibromatosis.

A 45-year-old male with von Recklinghausen's disease was noted to have hamartomatous lesions of the retinae similar to those more commonly described in Bourneville's disease and von Hippel-Lindau's disease. These findings would appear to support the concept that the retinal changes in neurofibromatosis occupy an intermediate position between those seen in the other two phakomatoses.

Causes of initial visual loss following blunt ocular injuries: an experimental study.

We have investigated in anaesthetised pigs the electrical responses of the retina to light after blunt injuries to the eye. Retinograms, cortical visual evoked responses and intraocular pressures were recorded before and after non-perforating mechanical trauma of sufficient severity to produce traumatic retinal opacification. After injury, applanation pressures rose up to 34 mm. Hg above normal, reaching peak values 4 to 12 minutes after trauma and returning to pre-trauma levels after about 45 minutes. These pressure changes were not responsible for the immediate abolition of the B wave of the retinogram or of the cortical visual evoked responses which occurred after trauma, but increases of intraocular pressure modified the recovery pattern of the visual evoked response.