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Information

Editors

MarjaHonkamo
VilleSaarela

Glaucoma

Essentials

  • Glaucoma is a progressive neuropathy of the optic nerve leading to damage of the optic disc, the nerve fibre layer and the visual field. It is a significant cause of visual impairment in the elderly.
  • In most patients, open-angle glaucoma is a slowly progressive disease causing few symptoms for a long time. More than half of the patients are unaware of having the disease.
  • Intraocular pressure is normal in about half of patients.
  • The diagnosis and follow-up of open-angle glaucoma require the equipment and special skills of an ophthalmologist. Some of the intraocular pressure checks can be done in primary health care.
  • Lowering the intraocular pressure by medication, laser treatment or surgery is essential in the treatment of glaucoma.
  • A general practitioner should primarily be able to recognize the symptoms of an acute glaucoma attack, master the diagnosis and know the principles of acute care.

Acute angle-closure glaucoma

  • It is vital that the diagnosis and treatment of acute glaucoma are not delayed.
  • Mere suspicion of acute angle-closure glaucoma warrants consultation by phone of an ophthalmologist on call at the nearest hospital with an ophthalmology unit in order to ensure appropriate treatment without delay.

Symptoms

  • Headache and eye pain
  • Often nausea and vomiting
  • Eye redness
  • Occasionally seeing a rainbow halo around lights (cause: corneal oedema)
  • Visual impairment

Findings

  • Measuring of the intraocular pressure is the primary diagnostic procedure: usually over 50 mmHg.
  • Impaired visual acuity
  • Conjunctival erythema
  • Mid-dilated pupil non-responsive to light
  • Opaque or greyish cornea
  • The eyeball may feel hard on palpation through the lid.

Initial treatment

  1. Lower the intraocular pressure with 500 mg of acetazolamide(i.v., p.o. or i.m.).
    • Intravenous administration is fastest and most effective.
    • A nauseous patient cannot take tablets.
    • Intramuscular injection may be painful.
    • Allergy to sulphonamides is a contraindication.
  2. Pilocarpine eye drops can be used, 1 drop a total of 3 times at 10-15-minute intervals.
  3. In addition, one timolol eye drop can be given if the patient does not have
    • asthma
    • bradycardia or
    • II-III degree AV block.
  4. Refer the patient immediately to an emergency ophthalmology unit where medication to lower intraocular pressure will be continued and laser peripheral iridotomy performed.
    • Referral must not be delayed because of starting medication. Eye drops can also be given on the way to an emergency opthalmology unit.

Open-angle glaucoma Medical Treatment of Glaucoma and Intraocular Hypertension

  • Open-angle glaucoma is a progressive neuropathy of the optic nerve leading to typical structural and functional defects of the optic disc, the nerve fibre layer and visual field.
  • In most patients open-angle glaucoma is a slowly progressing disease in which changes may take years to be noticed.
  • Glaucoma requires life-long treatment and follow-up.

Findings

  • Visual acuity and intraocular pressure
    • Normal central visual acuity and statistically normal intraocular pressure (10-21 mmHg) do not exclude open-angle glaucoma.
    • As many as half of patients with glaucoma have normal intraocular pressure.
    • The risk of glaucoma damage increases when intraocular pressure rises (particularly when it exceeds 30 mmHg).
    • Intraocular pressure may be elevated to 21-30 mmHg without optic disc abnormalities and visual field defects (so-called ocular hypertension).
  • Typical fundoscopic finding
    • The optic discs in the right and left eye may appear asymmetric (picture 1).
    • The central cup may be enlarged or drop-like in shape (picture 2) or paler than in the other eye.
  • Finger confrontation perimetry
    • Finger confrontation perimetry only reveals very advanced visual field defects caused by glaucoma.
  • The diagnosis is confirmed in specialized care by visual field test and fundus imaging.
    • Glaucoma can be diagnosed if there are two of the following three findings: excavation of the optic disc, neurofibrillary damage or visual field defect.
    • Intraocular pressure exceeding 30 mmHg should be treated even if no damage is visible.

Risk groups

  • The possibility of glaucoma should be remembered especially in high-risk group patients (Table T1).

Risk factors for glaucoma. Source: Finnish Current Care Guideline on the treatment of glaucoma, 2023

Risk factors1) Size of the risk
AgeDoubles about every 10 years
Intraocular pressure
  • 22-29 mmHg
  • > 30-35 mmHg
  • 10-13-fold
  • 40-fold
Exfoliation of the lens combined with increased intraocular pressure5-10-fold compared to increased intraocular pressure alone
A haemorrhage in the optic nerve head12-fold
Myopia2-4-fold
Family history3-fold
Lowered perfusion pressure associated with age3-fold
1) In addition, African ethnic background has been found to be a risk factor.
Glaucoma may also be secondary, i.e. caused by other eye disease.
  • For example, glaucoma associated with chronic iritis, circulatory disorders in the eye or eye injuries
  • Paediatric glaucoma is usually associated with an either congenital or hereditary structural anomaly or other eye disease.
  • Non-targeted screening for glaucoma has not been found to be cost-effective and is not recommended.
  • If glaucoma is suspected, the patient should be referred for assessment by an ophthalmologist.

Treatment

  • Glaucoma is treated by lowering the intraocular pressure by
    • laser treatment
    • medication
    • surgery.
  • Most patients with glaucoma require permanent medication.
  • Glaucoma drugs are usually administered topically as eye drops.
  • Some glaucoma drugs contain two active ingredients.

Drug therapy

  • Drug therapy is usually started with prostaglandin derivatives.
  • Drugs from other groups can be added to the regimen, as necessary.
  • Local irritation or allergy symptoms are the most common adverse effects of glaucoma drugs.
  • Topically used glaucoma drugs may also cause systemic adverse effects (many rarer adverse effects are not listed below; check relevant drug information sources for more details).
    • Prostaglandin derivatives (latanoprost, travoprost, bimatoprost, tafluprost)
      • No common systemic adverse effects have been observed.
      • Not recommended for use during pregnancy (risk of placental abruption)
    • Non-selective beta-blockers (timolol)
      • Bradycardia, hypotension, aggravation of asthma, dizziness, nausea, depression, sleep disturbances
      • Non-selective beta-blockers should not be prescribed to patients with asthma, slow heart rate, low blood pressure, untreated cardiac insufficiency or II-III degree AV block.
    • Selective beta-blockers (betaxolol)
      • As these have less effect on bronchial smooth muscle, they may be tolerated by some patients with asthma.
      • Cardiac effects and contraindications are similar to timolol.
    • Topical carbonic anhydrase inhibitors (dorzolamide, brinzolamide)
      • Disturbances of taste, dry mouth. Other adverse effects of sulphonamides and carbonic anhydrase inhibitors are also possible.
    • Systemic carbonic anhydrase inhibitors (acetazolamide)
      • Fatigue, dizziness, GI tract disturbances, metabolic acidosis, depression, tingling of extremities, hypersensitivity reactions, hypokalaemia, renal stones
    • Alpha agonists (apraclonidine, brimonidine)
      • Dry oral and nasal mucosa, taste disturbances, slowing of the heart rate and hypotension, fatigue
    • Parasympathomimetics (pilocarpine)
      • Headache at the beginning of treatment; other systemic effects are rare.
  • Systemic absorption and, therefore, adverse effects can be essentially reduced by pressing on the inner canthus for a few minutes after instilling the eye drop.
  • It is worth asking the patient about the use of eye medication in addition to asking about other medicines, as some patients do not remember to mention it.
  • Drugs used for other diseases may raise intraocular pressure (e.g. glucocorticoids, parasympatholytics).

Follow-up

  • Specialized care is responsible for the follow-up of glaucoma.
    • Visual field tests and fundus imaging are done every 1-2 years.
    • The ophthalmologist interpreting the tests assesses whether continuing follow-up is still useful for a patient of very advanced age or in institutional care.
  • Elevated intraocular pressure is normally checked every 6 months. Some checks can be done in primary health care or in the private sector.
    • Patients should know the individual target for the treatment of their intraocular pressure.

    References

    • [Glaucoma]. A Current Care Guideline. Working group appointed by the Finnish Medical Society Duodecim, the Finnish Society of Ophthalmology and the Finnish Glaucoma Society. Helsinki: the Finnish Medical Society Duodecim, 2023 (accessed 1.6.2023). Available in Finnish at http://www.kaypahoito.fi/hoi37030.
    • European Glaucoma Society. Terminology and Guidelines for Glaucoma (5th ed.). PubliComm, Savona, Italy, GECA Srl (2020) http://www.eugs.org/eng/guidelines.asp#.