treatment of chronic simple glaucoma

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Disc cupping and field loss progress at a variable rate, leading to profound field loss constriction and ultimately blindness.

Management aims to lower the intra-ocular pressure sufficiently to arrest progressive visual field loss.

  • even though increased IOP is not the only cause of glaucomatous neuropathy, it is one of the few risk factors which can be modified (1)
  • normal and damaging levels of intra-ocular pressure cannot be easily quantified but must be assessed at each examination by comparison to visual fields, intra-ocular pressure and disc appearance previously.

Medical and surgical treatments are available. The aim is to increase the efficiency of drainage or reduce the production of aqueous.

There is evidence that suggests previous multiple medical therapy increases the risk of failure of surgical treatment. It is for this reason there is an increasing trend to recommend surgery as a primary treatment, or after failure to control intraocular pressure with a single topical agent (for example, if the pressure remains above 21 mmHg) (1).

NICE suggest that (2):

  • take into account any cognitive and physical impairments when making decisions about management and treatment
  • check that there are no relevant comorbidities or potential drug interactions before offering pharmacological treatment
  • Treatment for people with COAG
    • Treatment for people with advanced COAG
      • offer people with advanced COAG, glaucoma surgery with pharmacological augmentation (mitomycin-C (MMC) as indicated
      • offer people who present with advanced COAG and who are listed for glaucoma surgery, interim treatment with a generic prostaglandin analogue (PGA)

    • Initial treatment for people with COAG
      • offer 360 degree selective laser trabeculoplasty (SLT) to people with newly diagnosed COAG (excluding cases associated with pigment dispersion syndrome). To help inform their decision, tell people:
        • that having 360 degree SLT can delay the need for eye drops and can reduce but does not remove the chance they will be needed at all
        • how long it may take for their IOP to improve after the procedure
        • about 360 degree SLT-specific side effects and complications and how long they are likely to last
        • that a second 360 degree SLT procedure may be needed at a later date
    • consider a second 360 degreee SLT for people with COAG if the effect of an initial successful SLT has subsequently reduced over time

    • offer a generic PGA to people with COAG if:
      • they choose not to have 360 degree SLT or
      • 360 degree SLT is not suitable (for example because they have pigment dispersion syndrome) or
      • hey are waiting for an 360 degree SLT and need an interim treatment or
      • they have previously had 360 degree SLT but need additional treatment to reduce their IOP sufficiently to prevent the risk of visual impairment

    • ongoing treatment for people with COAG
      • encourage people to continue with the same pharmacological treatment unless:
        • their IOP cannot be reduced sufficiently to prevent the risk of progression to sight loss
        • there is progression of optic nerve head damage
        • there is progression of visual field defect
        • they cannot tolerate the medicine

    • if satisfactory adherence to treatment and eye drop instillation technique whose IOP (intraocular pressure) has not been reduced sufficiently to prevent the risk of progression to sight loss
      • offer 1 of the following to people with satisfactory adherence to treatment and eye drop instillation technique whose IOP has not been reduced sufficiently to prevent the risk of progression to sight loss:
        • a medicine from another therapeutic class (a beta-blocker, carbonic anhydrase inhibitor or sympathomimetic); topical medicines from different therapeutic classes may be needed at the same time to control IOP or
        • 360 degree SLT or
        • glaucoma surgery with pharmacological augmentation (MMC) as indicated

    • consider 360 degree SLT or glaucoma surgery with pharmacological augmentation (MMC) as indicated for people with COAG who are at risk of progressing to sight loss despite treatment with medicines from 2 therapeutic classes

    • if COAG and cannot tolerate a pharmacological treatment:
      • consider 1 of the following for people with COAG who cannot tolerate a pharmacological treatment:
        • a medicine from another therapeutic class (a beta-blocker, carbonic anhydrase inhibitor or sympathomimetic) or
        • preservative-free eye drops if there is evidence that the person is allergic to the preservative or has clinically significant and symptomatic ocular surface disease
        • after treatment with medicines from 2 therapeutic classes, consider 360 degree SLT or glaucoma surgery with pharmacological augmentation (MMC) as indicated

    • if COAG whose IOP has not been reduced sufficiently to prevent the risk of progression to sight loss after glaucoma surgery
      • offer 1 of the following to people with COAG whose IOP has not been reduced sufficiently to prevent the risk of progression to sight loss after glaucoma surgery:
        • pharmacological treatment; topical medicines from different therapeutic classes may be needed at the same time to control IOP or
        • further glaucoma surgery or
        • 360 degree SLT or
        • cyclodiode laser treatment

    • if COAG (including advanced COAG) who prefer not to have glaucoma surgery or for whom glaucoma surgery is not suitable
      • offer 1 of the following to people with COAG (including advanced COAG) who prefer not to have glaucoma surgery or for whom glaucoma surgery is not suitable:
        • pharmacological treatment; topical medicines from different therapeutic classes may be needed at the same time to control IOP or
        • 360 degree SLT (for example in people with systemic comorbidities) or
        • cyclodiode laser treatment

Management undertaken by ophthalmologists includes (3):

  • prostaglandin analogues – as first choice
  • beta blockers – as second choice
  • other useful drugs like carbonic anhydrase inhibitors or alpha agonists can be used
  • in refractory cases – oral carbonic anhydrase inhibitors may be necessary
  • surgery – laser trabeculoplasty, trabeculotomy may be required (3)

Notes:

  • the NICE committee agreed that the key outcome for adults with ocular hypertension (OHT) or chronic open angle glaucoma (COAG) was visual field progression that, in the long-term, could affect people's vision (2)
    • intraocular pressure (IOP) was considered to be a relevant surrogate outcome because lowering IOP can prevent the risk of optic nerve damage and sight loss
    • high-quality evidence showed that there is no meaningful difference between 360 degrees selective laser trabeculoplasty (SLT) and eye drops in achieving a target IOP, health-related quality of life, risk of total adverse events, and treatment adherence
    • highlighted that there are rare complications associated with SLT
      • while rare events were not highlighted in the evidence, corneal failure is possible after SLT procedures
    • in people who have first-line treatment with eye drops compared with first-line 360 degrees SLT, more people used eye drops and more people have more than 1 eye drop medication at 12 months
    • cost-effectiveness evidence showed that first-line treatment with 360 degrees SLT was more effective and less costly compared with eye drops, with at least 90% probability of being the more cost-effective option
    • based on this evidence and their clinical experience, the committee recommended 360 degrees SLT as first-line treatment for people with newly diagnosed OHT or newly diagnosed COAG
      • recommendation excludes cases associated with pigment dispersion syndrome
        • was because there was no evidence on the use of 360 degrees SLT in people with pigment dispersion syndrome and the committee agreed that eye drop treatment is more suitable for those people

Reference:

Last edited 02/2022 and last reviewed 02/2022

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