The British journal of ophthalmology
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The role of orbital computed tomography (CT) in the management of retinoblastoma is reviewed. All 21 patients with retinoblastoma studied with high-resolution computed tomography had intraocular calcification demonstrable in at least one eye. 83% of tumours showed evidence of calcification on CT scan. ⋯ In patients under 3 years old in whom a retinoblastoma is suspected the presence of calcification on CT is virtually diagnostic of it. Patients with leucocoria without calcification on CT probably have a simulating lesion.
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Contrast sensitivity was measured in the eyes of 200 consecutive patients attending the glaucoma family screening unit. One-third of the patients screened had an abnormal contrast sensitivity. Positive correlation (p less than 0.01) existed between this abnormal contrast sensitivity and cup : disc ratio, visual field loss, and age. No such correlation existed between contrast sensitivity and intraocular pressure.
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In a 2-year prospective study of 76 patients with traumatic hyphaema seen at the Ahmadu Bello University Hospital, Kaduna, 75% were under 20 years of age. A low male to female ratio of 3 to 1 relative to other reports was noted. Hyphaema occurred in the left eye 1.6 times more often than in the right eye. ⋯ The final vision was worse as the level of hyphaema increased. Thus of 13 patients with vision of no perception of light, 8 (61.5%) had total hyphaema. The reasons for some of the differences from other reports are discussed and suggestions are offered as to ways of improving the visual outcome from the disease.
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Case Reports
Correlation of aqueous humour lactic acid dehydrogenase activity with intraocular pathology.
An analysis of the lactic acid dehydrogenase (LDH) activity in the aqueous humour of 24 enucleated eyes with retinoblastoma showed that though there was no relationship between the LDH levels and the age of the patient, there appeared to be an increase in the LDH activity with increase in the duration of the tumour. Undifferentiated tumour cells and tumour cell necrosis seemed to contribute to an increase of LDH levels in the aqueous humour, but there was no relationship between the occurrence of calcification and the LDH secretion into the aqueous humour. Massive cell necrosis caused by radiotherapy and central retinal artery occlusion significantly increased the LDH levels in the aqueous. It also appeared that recurrence was common after external cobalt therapy and that secondary extension of the tumour into the optic nerve and choroid was favoured by this procedure.