Glaucoma Diagnosis and Treatment

Created: 15.03.2023 · Last Updated: 20.08.2026 · Category: Ophthalmology · Prepared by the Academic Hospital Web and Editorial Board.

What Is Glaucoma?

Glaucoma is a group of eye diseases that can progressively damage the optic nerve at the back of the eye.

The optic nerve carries visual information from the eye to the brain. Progressive glaucomatous damage can cause permanent visual-field loss.

The most common form, open-angle glaucoma, usually develops slowly and may cause no noticeable symptoms during its early stages.

Glaucoma is not simply “high eye pressure.” Elevated intraocular pressure is an important risk factor, but not everyone with high pressure develops glaucoma, and glaucoma can occur even when eye pressure is within the statistically normal range.

Are Glaucoma and High Eye Pressure the Same?

No. Intraocular pressure (IOP) describes the pressure inside the eye.

Elevated IOP increases the risk of optic-nerve damage, but some people have elevated IOP without glaucomatous optic-nerve damage. This may be described as ocular hypertension.

Conversely, normal-tension glaucoma can occur in people whose measured eye pressure is not considered abnormally high.

Glaucoma therefore cannot be diagnosed from an eye-pressure reading alone.

What Are the Symptoms of Glaucoma?

Open-angle glaucoma typically causes no symptoms in its early stages.

As the disease progresses, patients may develop:

  • Loss of peripheral vision
  • Blind spots in the visual field
  • Progressive narrowing of the visual field
  • Central vision impairment in advanced disease

A greenish colour change of the eye is not considered a typical modern clinical symptom of open-angle glaucoma.

What Is Acute Angle-Closure Glaucoma?

In acute angle closure, the drainage angle inside the eye can become blocked suddenly, causing eye pressure to rise rapidly.

Seek urgent ophthalmic care for sudden onset of:

  • Severe eye pain
  • A red eye
  • Sudden blurred vision
  • Halos around lights
  • Headache
  • Nausea or vomiting

Acute angle-closure glaucoma is a medical emergency because vision can be threatened rapidly.

How Is Glaucoma Diagnosed?

No single test is sufficient to diagnose glaucoma in every patient.

Assessment can include:

  • Intraocular pressure measurement
  • Optic-nerve examination
  • Visual-field testing
  • Optical coherence tomography (OCT)
  • Central corneal thickness measurement
  • Gonioscopy to assess the drainage angle
  • Dilated eye examination

Testing and follow-up intervals are individualised according to glaucoma type, risk and evidence of progression.

What Do OCT and Visual Field Tests Show?

OCT provides high-resolution structural information about the retinal nerve fibre layer and structures surrounding the optic nerve.

Visual-field testing assesses the functional effect of glaucoma and can identify areas in which visual sensitivity has been reduced.

OCT therefore provides predominantly structural information, while visual-field testing provides functional information. Both can be useful for diagnosis and monitoring.

What Are the Risk Factors for Glaucoma?

  • Elevated intraocular pressure
  • Increasing age
  • A first-degree relative with glaucoma
  • High myopia
  • Thin central cornea
  • Prolonged or intensive corticosteroid exposure
  • Certain previous eye injuries or eye diseases

Low eye pressure itself should not be presented as a standard glaucoma risk factor. Normal-tension glaucoma describes optic-nerve damage occurring despite IOP readings that are not considered abnormally high.

Why Is Early Diagnosis Important?

Optic-nerve damage and visual loss that have already occurred from glaucoma are generally irreversible.

The purpose of treatment is therefore to preserve remaining vision and reduce the risk of further damage.

Because open-angle glaucoma may be asymptomatic in its early stages, examination schedules should be based on individual age, family history, IOP, optic-nerve findings and other risk factors rather than waiting for symptoms.

How Is Glaucoma Treated?

The central aim of glaucoma treatment is to lower intraocular pressure sufficiently to reduce the risk of additional optic-nerve damage.

There is no single target pressure that is suitable for every patient. The target can depend on disease severity, rate of progression, baseline IOP, age and other clinical factors.

Treatment may include:

  • Prescription eye drops
  • Laser treatment
  • Trabeculectomy
  • Glaucoma drainage implants
  • Minimally invasive glaucoma surgery (MIGS) in selected patients

How Do Glaucoma Eye Drops Work?

Glaucoma medicines lower IOP by reducing fluid production inside the eye or increasing fluid drainage.

Several medication classes can be used, including prostaglandin analogues, beta blockers, carbonic anhydrase inhibitors and other pressure-lowering medicines.

Treatment selection should consider both ocular findings and the patient's general medical condition.

Glaucoma eye drops do not restore vision that has already been lost. Their purpose is to lower pressure and reduce the risk of additional damage.

When Is Laser Treatment Used for Glaucoma?

Laser treatment is not limited to patients whose eye drops have failed.

Selective laser trabeculoplasty (SLT) can lower IOP in open-angle glaucoma by improving fluid drainage through the trabecular meshwork.

Current NICE recommendations offer 360° SLT as an initial treatment option for appropriately selected people with newly diagnosed chronic open-angle glaucoma that is not advanced.

The effect can diminish with time, and repeat SLT or additional pressure-lowering medication may later be required.

Different laser procedures, including laser peripheral iridotomy, can be used in angle-closure disease.

What Types of Glaucoma Surgery Are Used?

Surgery may be considered when adequate pressure control cannot be achieved with medicines and/or laser treatment, or when the risk of progression is sufficiently high.

  • Trabeculectomy: Creates an alternative pathway for aqueous fluid to leave the eye.
  • Glaucoma drainage implants: Use a tube or shunt to improve drainage.
  • MIGS: Includes a group of minimally invasive procedures that may be suitable for selected patients, often with less advanced disease.

No single surgical method is appropriate for every patient.

What Happens If Glaucoma Is Untreated?

Uncontrolled glaucoma can cause progressive optic-nerve damage.

Visual-field defects may gradually enlarge, and advanced glaucoma can eventually affect central vision and cause severe visual impairment or blindness.

Vision already lost to glaucoma is generally irreversible, but appropriate treatment and regular monitoring can slow or stop progression in many patients.

Regular Monitoring Is Important in Glaucoma

Glaucoma may cause no symptoms in its early stages. Intraocular pressure, optic-nerve examination, OCT and visual-field findings should be interpreted together when planning treatment.

Frequently Asked Questions

What is glaucoma?
Glaucoma is a group of eye diseases that can progressively damage the optic nerve at the back of the eye. Progressive disease can cause permanent visual-field loss.
Does everyone with high eye pressure develop glaucoma?
No. Elevated intraocular pressure is an important glaucoma risk factor, but not everyone with high pressure develops glaucoma. Glaucoma can also occur when measured eye pressure is within the statistically normal range.
Does glaucoma cause symptoms?
The most common form, open-angle glaucoma, usually causes no symptoms in its early stages. Progressive disease can cause peripheral visual loss and narrowing of the visual field.
Which glaucoma symptoms are an emergency?
Sudden severe eye pain, a red eye, blurred vision, halos around lights, headache, nausea or vomiting can indicate acute angle-closure glaucoma and require urgent ophthalmic assessment.
Can glaucoma be diagnosed from eye pressure alone?
No. Diagnosis can involve intraocular pressure measurement together with optic-nerve examination, OCT, visual-field testing, corneal thickness measurement and gonioscopy when appropriate.
Can vision lost from glaucoma return?
Optic-nerve damage and visual loss already caused by glaucoma are generally irreversible. Treatment aims to protect remaining vision and prevent or slow additional damage.
Is glaucoma laser treatment used only when eye drops fail?
No. Selective laser trabeculoplasty can also be considered as an initial treatment in appropriately selected patients with open-angle glaucoma. Treatment depends on glaucoma type, disease stage and individual factors.
Can glaucoma be completely cured?
There is currently no treatment that completely eliminates glaucoma or reverses established optic-nerve damage. Lowering intraocular pressure with medicines, laser treatment or surgery can substantially slow or stop disease progression.
Academic Hospital note: Glaucoma treatment should not be based on intraocular pressure alone. Optic-nerve damage, OCT and visual-field changes, disease progression and individual risk factors should be considered together. You can book an appointment.

References

  1. Academic Hospital. Glaucoma
  2. National Eye Institute. Glaucoma
  3. National Eye Institute. Glaucoma and Eye Pressure
  4. National Eye Institute. Types of Glaucoma
  5. NICE. Glaucoma: Diagnosis and Management