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Open-Angle Glaucoma F040

Document
Last amended 
15 December 2016
Current RMA Instruments
Reasonable Hypothesis SOP27 of 2012
Balance of Probabilities SOP 28 of 2012
Changes from previous instruments

SOP Bulletin 157

ICD Coding:
  • ICD-9-CM Codes: 365.1,365.3,365.4,365.51,365.52,365.81,365.82,365.89
  • ICD-10-AM Codes:  H40.1, H40.3-H40.8, H42
Brief description

Open-angle glaucoma is an optic neuropathy involving progressive peripheral visual field loss followed by central field loss. This usually (but not always) occurs in the presence of elevated intraocular pressure.  "Open-angle" refers to the anterior chamber angle, between the iris and the innermost surface of the cornea, which remains normal in this condition, unlike angle closure glaucoma, where it becomes narrowed or closed.  Open-angle glaucoma is the second most common cause of blindness (after cataract). 

Confirming the diagnosis

Diagnosis of glaucoma is based on findings of optic nerve damage on fundus examination and visual field abnormalities.  Slit lamp gonioscopy is used to visualise the anterior chamber angle and exclude angle-closure glaucoma.  The diagnosis needs to be made by an ophthalmologist.

Additional diagnoses covered by SOP
  • chronic simple glaucoma
  • ghost cell glaucoma
  • low tension glaucoma
  • normal pressure glaucoma
  • phacolytic glaucoma
  • pigmentary glaucoma
  • primary open-angle glaucoma
Conditions that may be covered by SOP (further information required)
  • neovascular glaucoma – this may be open-angle or angle-closure in type.

Conditions not covered by SOP

  • angle-closure glaucoma*
  • borderline glaucoma, ICD code 365.0
  • congenital glaucoma, ICD code 365.4

* another SOP applies

Clinical onset

The condition is nearly always asymptomatic and is detected incidentally during ophthalmological examination.  Clinical onset will coincide with confirmation of diagnosis in most cases.

Clinical worsening

Progression of the condition can be slowed or stopped with appropriate treatment.  A leading cause of disease progression is poor compliance with prescribed treatment.  Worsening beyond the normal course of the condition would generally be evidenced by more severe or rapid deterioration in vision (peripheral or central).

Comments

There are separate RMA SOPs for open-angle glaucoma and angle-closure glaucoma.

Of all non-congenital glaucoma cases:

  • Approximately 85% are primary open-angle glaucoma.
  • Approximately 10% are primary angle-closure glaucoma.
  • Approximately 5% are secondary glaucoma, either open-angle or angle-closure.

Open angle glaucoma is generally asymptomatic, even when it has progressed to peripheral field loss.  Angle-closure glaucomas may be symptom free or may present as a painful red eye or with loss of visual acuity.

A condition covered by an ICD code in the range of 365.62-365.65 may be either an open-angle type glaucoma or an angle-closure type glaucoma.