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Abstract #15456 Published in IGR 1-3
The well tempered crystal ball in normal tension glaucoma
Vernon SABritish Journal of Ophthalmology 1999; 83: 999-1000
In this editorial the author comments on a paper by Fontana and colleagues in the British Journal of Ophthalmology 1999; 83: 1002. The author is interested in risk factors for progression in so-called normal pressure glaucoma. The Fontana paper shows that there is about a 40% chance of developing a field defect within 5 years in the second eye of a patient who presents with unilateral NTG. Risk factors are a poor visual field in the first eye and a relatively small neuroretinal rim area in the so-called normal field eye as we would have expected. The author comments on the usefulness of studying neuroretinal nerve fiber layer in these cases. It is also useful to compare the relative size of the disc in the eye with the supposedly normal visual field. If the disc in the second eye and the nerve fiber layer are really normal it is worthwhile reconsidering the diagnosis particularly in the older patient. It is of interest that the Fontana study did not show intra-ocular pressure to be a predictive factor. The subtypes of glaucoma are not discussed in the study unfortunately. Nor has the corneal thickness been included as a subject. Other studies have identified systemic risk factors for progression in particular nocturnal hypotension and non-use of calcium channel blockers. It is of interest that this editor of the BJO seriously considers stopping any beta-blocking eyedrops or systemiccally taken beta-blockers since a study appeared that these drugs may be associated with nocturnal hypotension and progression of the disease. He concludes that until evidence of significant long-term advantage is established from carefully controlled trials it may be wise not to subject a normally cited eye and its owner to therapy which may have significant side-effects unless there are clear-cut signs of damage.
S.A. Vernon, University Hospital, Nottingham; United Kingdom
Classification:
9.2.4 Normal pressure glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)
