Glaucoma Management & Surgery

  • Introduction

    Glaucoma is a disease that involves damage to the optic nerve. The optic nerve head becomes cupped – an excavation of the central part of the nerve where nerve tissue has been lost. Cupping of the nerve leads to loss of peripheral, or side vision, which can impair many tasks. It can increase the risk of falls, and in some cases preclude driving.

    In most cases people are not aware of the loss of vision in glaucoma, even if it is quite severe. It is therefore important to have checks to ensure that glaucoma is detected early before there is significant loss of vision.

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      Right Eye - Healthy Optic Nerve

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      Left Eye - Cupping of Optic Nerve

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    Right Eye - Healthy Optic Nerve

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    Left Eye - Cupping of Optic Nerve

    1. Introduction
  • Eye pressure

    Traditionally glaucoma was thought of as a disease of high pressure. More recent research has confirmed that pressure is not the whole story. There are many people who develop glaucoma with pressures that are in the normal range, and others who have high pressures but do not develop glaucoma. There are a number of different factors that help a specialist to determine the risk of glaucoma either developing or progressing, and this risk assessment helps in the decision of whether or not treatment is required.

    There are two main forms of glaucoma – open angle glaucoma and closed angle glaucoma. It is very important to distinguish between the two, as the treatment for each is very different. The only way to differentiate between these two is to look directly at the drainage angle with a mirrored lens: gonioscopy.

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    This visual field test shows an inferior defect in a classic pattern for glaucoma

    2. Eye Pressure
  • Open angle glaucoma

    What is open angle glaucoma?

    Patients with open angle glaucoma have both damage to the optic nerve, and no blockage or closure of the main drainage area of fluid out of the eye.

    Treatment

    The main treatment for glaucoma is to lower the eye pressure. Even if glaucoma develops with ‘normal’ pressures, studies show that reducing the eye pressure further reduces the change of ongoing vision loss.

    • Drops:
      One option to lower pressure is eye drops. These must be taken regularly every day to ensure the pressure stays low. There are a number of different eye drops and your specialist will help select the best one for you, in part based on any other health problems you may have.

    • Laser:
      An alternative to drops for lowering pressure is Selective Laser Trabeculoplasty (SLT). For many patients remembering to take drops can be difficult, or there may be side effects from the drops that are unpleasant. SLT is a good option, and around 80% of people will achieve an acceptable reduction of pressure following SLT.

    • Cataract surgery:
      Patients with open drainage angles may have a small reduction in pressure with cataract surgery, but it often wears off over time. There are a number of new surgical devices becoming available, that when combined with cataract surgery may help to lower the intraocular pressure, or make patients less reliant on drops.

    • Trabeculectomy:
      For patients whose pressure is still too high despite drops and laser, surgery may be required. Trabeculectomy involves creating a new drainage hole from inside the eye to allow the fluid outside the eye, being resorbed underneath the outer skin of the eye, the conjunctiva.

    • Tube surgery:
      In patients requiring surgery for glaucoma, insertion of a plastic tube into the eye is another option. It is generally used when there is a high risk of a trabeculectomy failing, or when a previous trabeculectomy has already failed.

    3. Open angle glaucoma
  • Closed angle glaucoma

    What is closed angle glaucoma?

    In patients with closed angle glaucoma, the drainage angle of the eye is closed over by the peripheral iris. While some patients may have a very high attack of pressure that needs a visit to an emergency department, more commonly, people have chronic angle closure and do not have any major symptoms. It is therefore important to have a check of the drainage angle to make sure that is remains open. A cataract is a clouding and enlargement of the natural lens of the eye, as this occurs, it contributes to progressive narrowing of the drainage angle.

    Treatment

    Some people with narrow drainage angles do not need any treatment, other than a regular review to look at the drainage angles with a gonioscopy lens.

    • Laser peripheral iridotomy
      Once more than half of the drainage angle has closed over, a number of studies suggest it is important to open the drainage angle. The most common method of doing this is a laser peripheral iridotomy. This involves making a small hole in the coloured part of the eye, the iris, which allows the pressure on either side of the iris to become the same. In most instances this prevents an acute attack of high pressure, and also reduces the chance patients will go on to develop chronic angle closure.

    • Cataract surgery
      Performing cataract surgery, or removing the natural lens of the eye that has gone cloudy, is very good at opening narrow drainage angles. If you have a cataract that is diminishing your vision and narrow drainage angles, cataract surgery is a better option than laser peripheral iridotomy. In patients whose cataract is early and not causing visual problems, the decision to perform surgery is more complex, and is best discussed with your glaucoma specialist.

    • Drops
      Sometimes the pressure starts to rise in patients with narrow angle glaucoma, even after their drainage angle has been opened. In this situation drops are a good option to control the pressure.

    4. Closed angle glaucoma

For more information about glaucoma and services available, Glaucoma Australia have helpful resources.