NHMRC Glaucoma Guidelines - ANZGIG

NHMRC GUIDELINES FOR THE SCREENING, PROGNOSIS, DIAGNOSIS, MANAGEMENT AND PREVENTION OF GLAUCOMA
Chapter 6 – Identifying those at risk of developing glaucoma
Optic disc haemorrhage
Optic disc rim haemorrhages are significant risk factors for the development of glaucoma, as
indicated in the Blue Mountains Eye Study (Mitchell et al 1996). The Ocular Hypertension
Treatment Study (Budenz et al 2006) reported that subjects with optic disc rim haemorrhage were
twice as likely to progress to glaucoma as those without. The Early Manifest Glaucoma Treatment
Trial (Leske, Heijl, Hyman et al 2004) reported that those with optic disc rim haemorrhage were
more likely to progress, with a strong relationship being reported between frequency of optic disc
rim haemorrhage and risk of progression. Optic disc rim haemorrhage is an effervescent finding
and is clearly visible for approximately six weeks after formation. A notch or nerve fibre defect may
be left after the resolution of the acute haemorrhage. This can be an indicator of development or
progression of glaucoma to a health care provider examining the eye.
Evidence Statement
• Evidence supports past signs, or current presence, of optic disc haemorrhages as significant risk factors
for the development and progression of glaucoma.
• Evidence supports more agressive treatment of patients with ocular hypertension, or glaucoma, who
present with optic disc rim haemorrhages, or evidence of past optic disc rim haemorrhages.
Central corneal thickness
Data from the Ocular Hypertension Treatment Study (Budenz et al 2006) suggest that individuals
with thinner corneas are at increased risk of developing glaucoma. Corneal thickness is known to
affect the calibration of applanation tonometry, commonly used to measure IOP. Thin corneas are
associated with a greater IOP than is measured by tonometry and thus people with thin corneas
may obtain less accurate IOP readings. Thus, whilst the role of central corneal thickness as a
risk determinant of glaucoma still requires clarification, assessment of central corneal thickness
is considered to be a useful component of assessment of risk when making a decision to treat a
patient with OH (Dueker, Singh, Lin et al 2007).
These guidelines recommend a standard approach to the assessment of IOP and are detailed in
Chapter 7.
Evidence Statement
• Evidence supports the assessment of cup:disc ratio, and cup:disc ratio asymmetry, when assessing the risk
of glaucomatous damage occurring.
58 National Health and Medical Research Council