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Biomedical subjects

R Mapstone

Publications and source records attributed to R Mapstone.

At least 37 records · Page 2Linked to original sources
PubMed1977

Outflow changes in normal eyes after closed-angle glaucoma.

Twenty-four patients with spontaneous acute closed-angle glaucoma in one eye were selected for study. All 24 eyes had a peripheral iridectomy, were normotensive, and had no gonioscopically visible peripheral anterior synechiae. Of the 24 contralateral eyes 14 gave a positive response to provocative tests and had peripheral iridectomy. The remaining 10 eyes did not give positive responses to the tests and were on no treatment. The 24 pairs of eyes were provoked with pilocarpine and phenylephrine. Tonography was performed at the start of the test, 1 1/2 hours later, and at its termination. At the start of the test the 24 eyes that had had spontaneous closed-angle glaucoma showed a higher pressure and lower outflow facility than the 24 contralateral eyes. This difference disappeared as the test progressed. It is concluded that apparently normal eyes--after an acute attack--do none the less show a significant degree of damage to the outflow system. Ten pairs of eyes from 10 normal persons were provoked in a similar fashion and at no point did a significant difference appear between right and left eyes.

Acute Disease↗
PubMed1977

Normal response to pilocarpine and phenylephrine.

Fifty-eight eyes from 58 patients in which there was no evidence of glaucoma were provoked with pilocarpine and phenylephrine drops. The result was a significant reduction in intraocular pressure and a significant increase in outflow facility. The 58 eyes were randomised and 19 submitted to a 'dummy' provocative test. There was no significant change in either pressure or outflow facility. The effect of the pilocarpine/phenylephrine provocative test in normal eyes is to produce a response that is the opposite of a positive provocative test in eyes at risk of developing closed-angle glaucoma.

Drug Combinations↗
PubMed1977

Dilating dangerous pupils.

Altogether 85 eyes from patients at risk to the development of closed-angle glaucoma were dilated with either parasympatholytic or sympathomimetic drugs. Of 21 eyes dilated with cyclopentolate 1/2%, 9 developed angle closure and a significantly raised pressure at some stage during dilatation and subsequent miosis. Of 58 eyes dilated with tropicamide 1/2%, 19 developed angle closure and a significantly raised pressure during dilatation. Treatment with intravenous acetazolamide and pilocarpine rapidly returned pressure to normal levels. Six eyes that had previously had a positive provocative test with simultaneous pilocarpine and phenylephrine were safely dilated with phenylephrine alone. Subsequent miosis with pilocarpine produced closed-angle glaucoma in all eyes. The significance of these observations is explained and discussed, and it is suggested that high-risk eyes should never be dilated with cyclopentolate. Tropicamide is safe if elementary precautions are observed. Safest of all, however, is phenylephrine-induced mydriasis and subsequent miosis with thymoxamine drops 1/2%.

Acetazolamide↗
PubMed1977

Partial angle closure.

During the course of negative provocative test for closed-angle glaucoma using pilocarpine and phenylephrine 60% of eyes develop significant reductions in outflow facility at some stage during the test. It is shown that these reductions can be explained by postulating the presence of partial-angle closure since: (1) A random sample (6) of 53 eyes showing an abnormal response subsequently had a peripheral iridectomy. On reprovoking they then behaved as normal eyes with a uniform increase in outflow. (2) Fifty-eight eyes that had a peripheral iridectomy for closed-angle glaucoma (spontaneous or induced) responded to provocative testing as do normal eyes.

Drug Combinations↗
PubMed1976

Provocative tests in closed-angle glaucoma.

Altogether 119 eyes at risk of developing closed-angle glaucoma were provoked with simultaneous pilocarpine and phenylephrine; of these 74 developed closed-angle glaucoma. The remaining 45 eyes were re-provoked with tropicamide and a further nine developed closed-angle glaucoma. The 36 eyes in which all tests were negative were given no treatment and have been observed for a period of 1 to 7 years (mean 3 years). One has developed closed-angle glaucoma. A scheme for provoking eyes at risk of developing closed-angle glaucoma is described.

Adult↗
PubMed1976

The syndrome of closed-angle glaucoma.

Closed-angle glaucoma is the result of two mechanisms acting either separately or in combination: 1. Pupil block creates a greater pressure in the posterior than in the anterior chamber, pushing the iris on to the cornea. 2. Increased trabecular meshwork outflow in the presence of pupil block creates a lower pressure in the anterior chamber than in the posterior, pulling the iris on to the cornea. Three main groups of eyes manifest closed-angle glaucoma: (i) Mechanism (I) is necessary and sufficient, but (2) precludes the development of angle closure. (ii) Mechanism (I) is necessary but insufficient. Mechanism (2) must also be present. (iii) Mechanism (I) is necessary and sufficient but (I) and (2) may combine to produce an acute attack.

Amides↗
PubMed1975

Miotics in closed-angle glaucoma.

The use of intravenous Diamox with variable doses of Pilocarpine was investigated in the treatment of primary closed-angle glaucoma. It was concluded that one drop of Pilocarpine 3 to 4 hrs after intravenous Diamox is the only parasympathomimetic drug necessary to terminated an acute attack.

Acetazolamide↗
PubMed1975

HL-A 27 and acute anterior uveitis.

51 (30 men and 21 women) of 90 consecutive patients with acute non-granulomatous anterior uveitis were HL-A 27 positive. This frequency of 55-7 per cent compares with 8-2 per cent in controls. Twenty-three patients (18 men and 5 women) had in addition evidence of systemic disease, including ankylosing spondylitis, sacroiliitis and Reiter's syndrome, sometimes associated with psoriasis. Twenty-eight of 63 patients without evidence of systemic disease were HL-A 27 positive, suggesting that the uveitis in many of these cases has a similar aetiology to those with rheumatic disease. The uveitis associated with HL-A 27 is typically unilateral, associated with mechanical ptosis, and a painful diffusely red, photophobic, and lacrimating eye, generally lasting 3 weeks or more. Protein extravasation into the aqueous is considerable, cells are usually present in the aqueous and anterior vitreous, and keratic precipitates are never mutton fat in appearance. Recurrent episodes are characteristic. The association with HL-A 27 suggests that many if not most cases of non-granulomatous anterior uveitis have a close aetiological relationship to ankylosing spondylitis and Reiter's syndrome and it is likely that infective agents, leading to an unusual immunologically mediated inflammatory response in predisposed individuals, are involved. Ten patients with granulomatous anterior uveitis were HL-A 27 negative.

Adult↗
PubMed1975

HL-A27 and anterior uveitis.

HL-A types were determined in 90 successive patients with non-granulomatous uveitis. Fifty-one were HL-A27 positive (55.7%) compared to 8.2% of controls. Of 16 patients with ankylosing spondylitis, 13 were HL-A27 positive, as were two patients with a history of Reiter's syndrome. Twenty-eight patients were HL-A27 positive but had no evidence of rheumatic disease. The findings are discussed in relation to the possible pathogenesis of uveitis.

Acute Disease↗