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Tonography demonstrates reduced facility of outflow of aqueous humour in myocilin mutation carriers


Wilkinson, C and van der Straaten, D and Craig, JE and Coote, M and McCartney, PJ and Stankovich, J and Stone, E and Mackey, DA, Tonography demonstrates reduced facility of outflow of aqueous humour in myocilin mutation carriers, Journal of Glaucoma, 12, (3) pp. 237-242. ISSN 1057-0829 (2003) [Refereed Article]

DOI: doi:10.1097/00061198-200306000-00010


Purpose: To demonstrate the effect in vivo of the myocilin gene mutation Thr377Met on outflow facility of aqueous humor, as measured by tonography. Materials and Methods: Forty-two members of a pedigree known to carry the Thr377Met mutation were examined for glaucoma, evaluated with tonography, and screened for myocilin mutations. Tonography was used to calculate the coefficient of aqueous outflow facility (C), as well as the ratio of the resting intraocular pressure to C (P0/C). Subjects were reexamined for glaucoma 5 years after tonography. Results: Seven subjects were excluded because of previous treatment known to alter facility of aqueous outflow, The mean outflow facility of the eyes of the 12 subjects carrying the Thr377Met mutation was significantly reduced compared with the 23 non-carriers' eyes using both C (P<0.001) and P0/C (P<0.001). Reduced outflow facility was also demonstrated in those mutation carriers who were not yet expressing clinical signs of glaucoma or ocular hypertension when measured using C (P = 0.015) and P0/C (P = 0.001). After 5 years, progression towards glaucoma had occurred in 5 of the myocilin mutation-carriers, 2 of whom showed bilateral progression; 3 carriers remained completely normal. Four subjects had bilateral glaucoma at the outset and remained unchanged. The carriers' eyes that progressed towards glaucoma had reduced outflow facility compared with those that remained normal, although the difference was not statistically significant. Conclusions: Carriers of the myocilin Thr377Met mutation have reduced outflow facility, which may be detected prior to developing glaucoma. Tonography was not seen to be clinically useful in predicting progression towards glaucoma.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Ophthalmology and optometry
Research Field:Ophthalmology
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Craig, JE (Mr Jamie Craig)
UTAS Author:McCartney, PJ (Dr Paul McCartney)
UTAS Author:Stankovich, J (Dr Jim Stankovich)
UTAS Author:Mackey, DA (Professor David Mackey)
ID Code:48498
Year Published:2003
Web of Science® Times Cited:10
Deposited By:Menzies Institute for Medical Research
Deposited On:2007-10-12
Last Modified:2011-11-07

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