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
Risk factors for specific glaucoma types and stages
Angle closure
The American Academy of Ophthalmology [AAO] (2005a) states that risk factors for developing
angle closure are hypermetropia, family history of angle closure, advancing age, female gender,
Asian or Inuit descent and shallow anterior chamber for PACG. However, there is limited
quantification of the risk. Medical interactions/effects are also a proposed risk, however even
less is known about them. Schmier, Halpern and Jones (2007) state that the higher prevalence of
primary angle closure (PAC) and PACG in Asian and certain indigenous ethnic groups (e.g. Inuit)
suggests that ethnicity is a risk for that glaucoma type.
These guidelines report medications and conditions associated with the development of angle
closure states in Chapter 9.
Evidence Statement
• Expert/consensus opinion suggests that hypermetropia, family history of angle closure, advancing age,
female gender, Asian descent and shallow anterior chamber are risk factors for the development of angle
closure, and angle closure glaucoma.
Secondary glaucoma
There is no evidence from the secondary literature regarding the risk factors for, or progression
of secondary glaucoma.
Progression of established glaucoma
Risk factors for developing glaucoma are not necessarily the same as the risk factors for progression of
diagnosed glaucoma. However, the importance of IOP in early stage glaucoma has been underlined
by the results of the Ocular Hypertension Treatment Study (Budenz et al 2006), wherein univariate
and multivariate analyses found that every 1 mmHg increase in mean IOP level was associated with
a 10% increased risk of progression from OH to glaucoma. A meta-analysis of five relevant and
adequately powered studies (Maier, Funk, Schwarzer et al 2005) also concluded that using topical
pressure lowering medications for primary prevention of glaucomatous VF defects in patients with
OH appears to be effective. The Ocular Hypertension Treatment Study (Budenz et al 2006) also
reported that subjects with optic disc rim haemorrhage were four to six times as likely to progress
to glaucoma as those without optic disc rim haemorrhage. The Early Manifest Glaucoma Treatment
Trial (Leske et al 2004) concurred, reporting that patients with optic disc rim haemorrhage were
more likely to progress to glaucoma, with a strong relationship established between frequency of
optic disc rim haemorrhage and risk of progression.
Evidence Statement
Evidence indicates that factors associated with greater risk of glaucoma progression include elevated/
fluctuating intraocular pressure, optic disc haemorrhage, increased severity of glaucomatous disc damage
and very low blood pressure. These patients require greater reduction in intraocular pressure.
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