Glaucoma is an irreversible condition where the optic nerve, that connects the eye to the brain, is damaged. It is often asymptomatic as it tends to affect the peripheral vision initially. If left untreated, these changes become more central and can eventually lead to complete loss of vision.


Glaucoma is the leading cause of irreversible blindness worldwide and it is estimated that 70 million people are affected worldwide, 7 million being blind in both eyes. It is estimated that almost half a million people are affected with glaucoma in the UK, 1 in 50 in those over 40 years of age and 1 in 10 in those over 75 years of age.


Glaucoma is often categorised as primary, when no cause has been found, or secondary, when a cause has been identified. Glaucoma can then be subcategorised as open or closed depending on the anatomy of the drainage angle. Primary open angle glaucoma (POAG) is the most common type of glaucoma and while no cause has been identified, it is associated with a number of risk factors including increasing age, raised eye pressure (intraocular pressure, IOP) and a family history of glaucoma.


Primary angle closure glaucoma (PACG) occurs when the anatomical drainage of the eye is narrow resulting in a build up of fluid in the eye and associated raised IOP. This may occur gradually or suddenly as an ophthalmic emergency, acute angle closure glaucoma (AACG) where patients present with a red eye, headaches, blurred vision or haloes around lights (like a candle glow).


Secondary glaucoma is when a cause has been identified and these include steroid or lens induced, previous trauma, inflammation within the eye (uveitis), pseudoexfoliation (a type of protein deposition that occurs in the eye as well as the rest of the body) and pigment dispersion syndrome. A formal assessment by Dr Lee will be able to determine the presence and type of glaucoma.


Most types of glaucoma cannot be prevented but early detection of the disease and treatment to lower the eye pressure may reduce the risk of disease progression and therefore prevent irreversible sight loss.


Dr Lee will perform a number of tests to assess for glaucoma:


Intraocular pressure (IOP): This is the only risk factor that can be modified to reduce the risk of disease progression. At the optician, they will usually assess this with a non-contact ‘puff of air’ test that is a useful screening tool but not the most accurate assessment of IOP.


Central corneal thickness (Pachymetry): Most IOP measuring devices are calibrated for a certain level of corneal thickness and if a patient’s cornea is thicker or thinner than average, this may have a bearing on their IOP measurement, especially if performed via a non-contact device that often over-estimate IOP in patients with increased corneal thickness compared to the average population.


Anterior chamber assessment (Gonioscopy): This will be performed to assess whether the drainage of the eye is open or closed. If the drainage angle is closed, an ophthalmologist will discuss various treatments that may include laser or surgical options.


Fundal Assessment: An ophthalmologist will examine the back of the eye to determine whether there is evidence of damage to the optic nerve due to glaucoma as well as to assess for any other ocular pathology.


Imaging: A range of imaging techniques to assess for optic nerve damage, such as optical coherence tomography (OCT), can be used to assist diagnosis and monitoring of progression of glaucoma.


Visual Field Assessment (Perimetry): Glaucoma is characterised by loss of visual field and perimetry testing will assist diagnosis and monitoring of progression of glaucoma.


The only treatment option available for open angle glaucoma is to lower the IOP via several approaches.


Medical: There are several different classes of eye drops available to lower the eye pressure. These can be associated with local (red, dry eyes) or systemic side-effects.


Laser: These open up the drainage pathway of the eye or reduce the production of fluid inside the eye to lower the IOP.


While eye drops have conventionally been thought of as being the first line treatment for glaucoma, recent studies suggest that selective laser trabeculoplasty (SLT) should be considered as first line treatment for patients with open angle glaucoma for a number of reasons including:


  • Similar efficacy to eye drops at lowering IOP
  • Minimal risk
  • Less side effects associated with eye drops
  • Patients do not need to worry about putting drops in on a daily basis
  • Less risk of requiring surgery at a later date
  • More cost effective


Surgery: Surgery may be required if eye drops or laser treatment is not indicated, do not lower the IOP adequately or if there is evidence of glaucoma progression despite treatment.


Conventional surgery included a glaucoma filtration procedure (trabeculectomy) where a trapdoor is made in the sclera, the white of the eye, to allow fluid to drain from inside the eye to underneath the conjunctiva, the skin of the eye. These can also be achieved with a drainage device (aqueous shunt) that drains the fluid inside the eye via a tube to a plate that is secured to the sclera under the conjunctiva.


Minimally Invasive Glaucoma Surgery: These are a range of procedures that are usually performed together with cataract surgery to lower IOP. While some of these devices do not lower the IOP as much as conventional glaucoma surgery and therefore may not be suitable for all patients, advantages include:


  • Less risk of complications
  • Quicker surgical procedure
  • Reduced need for eye drop medication


To discuss glaucoma assessment and treatment in more detail, please feel free to arrange a consultation with Dr Lee by clicking here.