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Woon, W. H.; ffytche, T. J.; Hamilton, A. M.; Marshall, J.
doi: 10.1136/bjo.75.7.386pmid: 1854689
The Microlase infrared diode laser has recently become available for retinal photocoagulation. It uses a laser beam with a large convergence angle (23 degrees). This gives rise to a laser beam with a relatively large cross section at the subject's pupil. In this study the pupillary area required to view the fundus at the slit-lamp with a 90-dioptre lens is determined. It is found that the pupillary area required to view the fundus is smaller than the cross section of the Microlase laser beam at the pupil. Thus iris clipping of the laser beam can occur even though the surgeon has a clear and bright view of the fundus. Care should be taken to use the Microlase only in the presence of a widely dilated pupil.
Dua, H. S.; McKinnon, A.; McMenamin, P. G.; Forrester, J. V.
doi: 10.1136/bjo.75.7.391pmid: 1854690
Lewis rats were immunised with retinal S-antigen to induce experimental autoimmune uveitis and experimental autoimmune pinealitis. The blood-retinal and blood-pineal 'barrier sites' were examined by transmission electron microscopy. Inflammatory cell movement through Bruch's membrane involved separation of its constituent layers, cell migration through pores in the membrane, and between retinal pigment epithelial cells without causing significant displacement of the retinal pigment epithelial cell layer. The endothelial cells of retinal and pineal vessels with perivascular infiltrates showed morphological features resembling endothelium of 'high endothelial venules'.
doi: 10.1136/bjo.75.7.398pmid: 1854691
In this study 374 consecutive fundus fluorescein angiograms (FFAs) were performed on 330 patients. Of these, 165 (50%) were investigated for age related maculopathy. In only 12% did this investigation lead to an alteration in treatment. The remaining 50% of angiograms were requested for diabetic patients (15%), retinal vein occlusion (5%), tumours (6%), and various other disorders. In the diabetic patients treatment could have proceeded without FFA in 24% of patients who underwent it. Missed diagnoses corrected by angiography and areas where unnecessary angiograms were performed were identified. One interesting subgroup of eight patients with unexplained loss of central vision was identified. Careful clinical examination had failed to reveal any abnormality. FFAs were of no diagnostic value in these patients.
Small, K. W.; Killian, J.; McLean, W. C.
doi: 10.1136/bjo.75.7.401pmid: 1854692
We studied 34 family members at risk of having dominant progressive foveal dystrophy of Lefler, Wadsworth, and Sidbury (also called North Carolina macular dystrophy) and found 17 to be affected. Fifteen of these affected subjects were observed over at least a 10-year period for evidence of progressive macular degeneration. Only one subject showed objective evidence of progressive deterioration in only one eye. Our findings further substantiate that this dystrophy generally has a stable course, contrary to its original description.
Morley, M.; Finger, P. T.; Perlin, M.; Weiselberg, L. R.; DeBlasio, D. S.
doi: 10.1136/bjo.75.7.407pmid: 1854693
We have used intravenous cis-platinum chemotherapy in the treatment of three patients with basal cell carcinoma of the lid extending into the orbit. Cis-platinum chemotherapy caused a reduction in tumour size and thereby delayed surgery in all cases. It allowed for local resection in one case, appeared to delay a patient's exenteration in a second case, and was used prior to radiotherapy in a third case. While not curative, cis-platinum may be useful as an adjuvant to decrease tumour mass prior to local excision and for patients who refuse or must delay exenteration.
Trew, D. R.; Wright, L. A.; Smith, S. E.
doi: 10.1136/bjo.75.7.411pmid: 1677267
The ocular effects of the alpha-adrenoceptor blocking drug bunazosin, administered as eyedrops, have been measured in a placebo-controlled double-blind single-dose study in 15 healthy volunteers. The drug significantly reduced intraocular pressure over 10 hours, and there was no associated change in pulsatile ocular blood flow. Characteristic effects of alpha-adrenoceptor blockade were observed--miosis, ptosis, and conjunctival hyperaemia. The miosis alone persisted for more than 24 hours in nine out of 15 subjects.
Ingram, R. M.; Arnold, P. E.; Dally, S.; Lucas, J.
doi: 10.1136/bjo.75.7.414pmid: 1854694
In a sample of children used to assess the value of optical correction of hypermetropia from the age of 6 months the refraction of the most hypermetropic meridian frequently became less than 3.5 D as the children grew. When this occurred, the incidence of squint was significantly less (p less than 0.001) and the last known acuity after treatment was significantly better (p less than 0.001) than when it did not. This process of emmetropisation appears to have been impeded by the consistent wearing of hypermetropic spectacle correction from the age of 6 months.
Ropo, A.; Nikki, P.; Ruusuvaara, P.; Kivisaari, L.
doi: 10.1136/bjo.75.7.417pmid: 1854695
Ten patients undergoing cataract surgery were given a local anaesthetic with lignocaine solution which was mixed with iohexol contrast medium. The location of the needle and the substance injected was determined by computerised tomography following retrobulbar or periocular anaesthesia. The retrobulbarly inserted needles were within the muscle cone, directed towards the optic foramen. The periocular needles were outside the muscle cone, tangentially along the orbital floor or pointing slightly upwards. After the retrobulbar injection the contrast medium was seen within the cone immediately after the injection and outside the cone as early as 3 minutes after the injection. With the periocular technique, however, diffusion of the anaesthetic in the opposite direction (that is, into the muscle cone) was rapid. The contrast medium was identified inside the muscle cone 2 minutes after the injection. Compression with an intraocular pressure reduction device after both of these techniques prevented exophthalmos. It is concluded that retrobulbar-like anaesthesia can also be induced by an appropriate periocular technique.
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