Purchase this article with an account.
D. C. Broadway, S. P. Meredith, T. Eke, L. Swift; The Acute Morphological Changes That Occur at the Optic Nerve Head Induced by Medical Reduction of Intraocular Pressure. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3332.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The mechanical theory of glaucoma postulates that raised intraocular pressure (IOP) causes laminar distortion resulting in damage to axons at the optic nerve head. There is some evidence that the change in morphology may occur over a short time course. The aim of this study was to detail the acute morphological changes at the optic nerve head when IOP was lowered with medical therapy in a clinical population.
Subjects referred to the glaucoma clinic that had a documented IOP of over 28mmHg, on no treatment, in one or both eyes were included. Tonometry, pachymetry, and scanning laser ophthalmoscopy were performed before and after lowering IOP with topical apraclonidine and oral acetazolamide. The significance of change in outcome variables was assessed using a paired t test allowing for dependence within subjects and, for greater sensitivity, with a non-parametric Wilcoxon signed-rank test.
Data were obtained from 38 eyes of 19 patients with a mean age of 67 years. After lowering IOP for only one hour, there was a significant decrease in cup volume (a mean change in volume below surface of 26.8 microns3, p<0.001) and mean cup depth (13.8 microns, p<0.01), there being a corresponding increase in rim area (37.3 microns2, p<0.034).
In the present study it was shown that acute and statistically significant alterations in optic disc morphology occur when IOP is lowered medically with a combination of topical apraclonidine and systemic acetazolamide. The technique, therefore, may be useful to further investigate sub-groups of glaucomatous eyes and test aetiological hypotheses.
This PDF is available to Subscribers Only