Glaucoma is a disease of the optic nerve that carries information from your eye to your brain. It usually happens when fluid builds up in the front part of your eye. This increases the pressure in your eye, damaging the optic nerve. Glaucoma is usually a progressive disease associated with a characteristic type of damage (thinning) of the optic nerve and in most cases loss of peripheral vision.
Central vision is usually preserved until the disease is relatively advanced. Therefore most people with glaucoma are not aware of the disease unless it is picked up with special tests often at the opticians. Glaucoma tends to affect both eyes although sometimes one eye is more affected than the other.
One of the main causes for glaucoma is raised eye pressure, although about a third of patients with glaucoma have a normal eye pressure. The level of eye pressure is influenced by the amount of fluid (aqueous) produced by your eye and how efficiently this fluid can leave the eye through the drainage angle (trabecular meshwork). It is not always clear why the eye pressure is high in certain patients and additional tests such as gonioscopy are required to evaluate the drainage angle. The other major, and unfortunately non-modifiable, risk factor for glaucoma is age. The role of genetics in glaucoma is still being explored (please see Lascaratos et al Surv Ophth 2013 and Lascaratos et al Mitochondrion 2012) and about a third of patients have a blood relative with glaucoma. Ethnicity also plays a role and glaucoma tends to be more common and aggressive for example in African-Caribbean patients. Vascular factors, such as migraines, poor circulation in the hands or feet, or sudden loss of blood after an accident, should also be considered as they may influence the blood flow to the optic nerve causing damage. Your individual risk factors will be discussed with you during the consultation and form the basis for our management plan.
Unfortunately most patients with glaucoma do not experience any symptoms until the disease is relatively advanced. This is because in most individuals with glaucoma the eye pressure (while it can be high) is not high enough to cause eye pain or redness. Also, the majority of glaucoma patients only suffer peripheral loss of vision, with central vision usually affected at the later stages of the disease. The brain has an amazing capacity to fill in the gaps in the peripheral vision and often with both eyes open any gaps in the peripheral vision of one eye are filled in by the peripheral vision of the other eye. If you have a first degree relative with glaucoma please visit your optician to check your eye pressure (intraocular pressure check) and peripheral vision (visual field test). Your optician will also examine your optic nerve using special instruments and in many cases perform a scan of the optic nerve (optic disc imaging) and if necessary will refer you for further assessment and treatment. Alternatively in our specialist private locations we provide a service for glaucoma evaluation and screening. Should you wish to be seen directly by a glaucoma specialist please get in touch.
Our team is here to help you and make your visit as comfortable and efficient as possible. You will initially see an experienced nurse who will check your vision (please remember to bring your glasses with you). Then a specialist technician will check your peripheral vision (visual field test) and perform a detailed scan of your optic nerve (optic disc OCT) to detect and quantify any thinning of your nerve fibres in the different sectors of the optic nerve. During the consultation we will listen to your thoughts and concerns, discuss any questions you may have about glaucoma, and evaluate based on your history and clinical findings your individual risk of developing glaucoma or of the glaucoma progressing. Often more than one treatment options will be available and we would need to discuss the advantages and limitations of each approach and decide together on the most appropriate management plan. As part of your initial clinical assessment a special contact lens will be placed on the surface of your eye to evaluate your drainage angle (gonioscopy) and topical anaesthetic drops will be applied prior to this to numb the eyes. You may also need to have dilating drops to perform a more complete evaluation of the optic nerve and the retina at the back of your eyes, so please do not drive to your appointment. You should expect the consultation including the investigations to take approximately 1 hour. We always aim to provide the best possible care for you and your feedback at the end of the consultation would be most appreciated.
As Glaucoma is the most common cause of irreversible sight loss amongst those of working age, we understand the need for providing a tailored patient pathway that will provide you with everything you need to know about your condition. Mr Lascaratos is there to ensure that you are provided with everything you need in order to make an informed decision on the best way forward for you, and at your initial consultation, you can expect to receive a range of scans and tests including:
- Visual acuity test
- Intraocular pressure check
- Gonioscopy to evaluate the drainage angle
- Visual field (peripheral vision) test
- Optic disc OCT scan
- Fundoscopy to examine the optic nerve
Once these scans and tests are complete, Mr Lascaratos will review all of the information gathered and recommend a treatment plan, explaining all possible options that are open to you.
While vision loss from glaucoma is generally irreversible, the earlier the disease is recognised the higher the chance of preventing further vision loss. The main aim of treatment currently is to lower the eye pressure. At first diagnosis, most patients would be offered either treatment with eye drops or laser treatment (SLT) to lower the eye pressure. If you have advanced disease or if your eye pressure is inadequately controlled, surgery (trabeculectomy or tube surgery) may be more appropriate. Other types of laser, such as cyclodiode, are also available and suitable for certain patients. More recently we have been offering Minimally Invasive Glaucoma Surgery (MIGS), such as the iStent, especially to patients with less advanced glaucoma (either as a standalone procedure or at the same time as cataract surgery) to reduce reliance on eye drops and improve eye pressure control. Sometimes it may be appropriate to lower the eye pressure with tablets (acetazolamide) especially over a short period of time while waiting for surgery, since the tablets may not be well tolerated or safe over longer periods. All these options, including their risks and benefits, will be discussed during the consultation taking into account your individual circumstances.
While there is no strong evidence to suggest that specific lifestyle interventions can prevent or delay glaucoma progression, there is some evidence that oxidative stress and mitochondrial dysfunction are implicated in the damage of the retinal ganglion cells in the optic nerve (Lascaratos et al Neurobiology Dis 2015) and a diet rich in antioxidants may be helpful. Green leafy vegetables contain vitamins and other antioxidants that may be protective. Aerobic exercise has an additional cardiovascular benefit and has been shown to lower the eye pressure, while head-down positions such as in yoga and caffeine may increase your eye pressure. This increase in eye pressure may not be clinically significant if only small in size and of short duration, except perhaps in patients with advanced disease or with additional risk factors. Omega-3 fatty acids found in oily fish have also been shown to lower the eye pressure and therefore potentially benefit glaucoma patients.
This is a difficult topic and several factors need to be considered. It is important first of all to confirm that the glaucoma is actually getting worse as sometimes there is a fluctuation in the visual field or disc OCT measurements from one visit to the next, giving a false impression of change. Visual fields for example can be difficult for patients to perform and simple things, such as tiredness on the day or sitting position in front of the device, need to be taken into account. We can discuss this during your consultation and certain tests may need to be repeated to confirm this.
Other causes of worsening of your eyesight or your peripheral field of vision should also be excluded, such as cataract or diseases of the retina. A detailed clinical examination combined with a good history would normally distinguish between glaucoma and other diseases that can affect the vision and mimic glaucoma.Assuming we find that genuine glaucoma progression has occured, it is important to clarify whether your eye pressure is actually ‘good’. For example, if you have very thin corneas (where the front window of the eyes is thin) the eye pressure reading may appear artificially low, thus giving false reassurance. A special test called corneal pachymetry would confirm this. Also, often the eye pressure may appear to be good or within the normal range for the general population, but may still be high for you as an individual patient. In many cases we often find that reducing your eye pressure further (with drops, laser or surgery) to an even lower level can delay progression. Several factors, such as your blood pressure or fluctuations in your eye pressure during the day, may also be contributing to glaucoma progression and additional tests may be indicated to explore these. In some cases blood tests to exclude other causes of optic nerve damage may be required, as well as genetic tests and brain imaging, such as an MRI scan. Less frequently electrodiagnostic tests of the retina and optic nerve may become necessary and these options will be discussed with you during the consultation. These cases can be challenging and require an individualised approach which we are happy to offer.
More recently treatments (drops or tablets) to enhance mitochondrial function and potentially improve the function of damaged neurons in the optic nerve have emerged that may be relevant to patients with progressive glaucoma despite every attempt to lower eye pressure. Mr Lascaratos has significant experience in this field and can discuss the potential role of these treatments on a case by case basis.
It is interesting to consider for a second why ageing is such an important risk factor for glaucoma. What is it about age that makes individuals more likely to develop optic nerve damage? A good measure of ageing is how well our mitochondria work and mitochondrial function is known to decline as we get older. Mitochondria are the little compartments inside our cells that make a chemical called ATP that the body uses for energy. Importantly, it’s been shown that in the optic nerve the retinal ganglion cells (the cells that die off in glaucoma) have a high demand for energy and it is likely that if the mitochondria work less well with age, the optic nerve will suffer from not having the energy it requires. Recent work from our group has revealed for the first time that having healthy mitochondria in your peripheral blood cells is associated with an enhanced ability to withstand optic nerve injury (Lascaratos et al Neurobiology Dis 2015). Mr Lascaratos was honoured in 2017 to receive an NIHR Clinical Lecturer award from Fight for Sight to further understand the role of mitochondrial function as a biomarker for glaucoma. He is currently involved in several projects investigating the role of mitochondria enhancing treatments as a new approach to managing glaucoma.
The optic nerve is an extension of the brain and glaucoma is considered in many ways a neurodegenerative disease. The primary cells that are damaged in glaucoma are called retinal ganglion cells, although there is increasing evidence that damage to adjacent supporting cells, such as the glial cells, also plays a role. Mitochondrial dysfunction and oxidative stress are thought to force these cells to function at a lower than normal energetic state and, together with the accumulation of potential cytotoxins such as nitric oxide or TNF‐α in the extracellular space, may accelerate the loss of retinal ganglion cells by apoptosis (Osborne, Lascaratos et al 2006).
Neuroenhancement refers to therapeutic strategies to increase the function of the neurons in the optic nerve and the rest of the brain thus rescuing these cells from irreversible damage. While this is a controversial topic and further clinical trials are required in this field, neuroenhancement treatments have been studied in glaucoma patients and have been proposed to delay glaucoma progression potentially by a) enhancing the synthesis of neurotransmitters, such as dopamine and acetylcholine, in the brain and b) stabilising the cell membranes, thus preventing the release of cytotoxic substances that may lead to neuronal apoptosis. These treatments may be offered at any stage of the disease and it has been argued that there is a benefit in starting at the earlier stages before irreversible damage to the optic nerve has occurred. While every effort should be made to lower the eye pressure there is certainly a role for discussing these new approaches especially if your glaucoma is deteriorating (progressing) despite aggressive eye pressure lowering treatments. For a full and honest discussion about whether these treatments are right for you please contact us to arrange a face-to-face consultation with Mr Lascaratos.
MIGS can be a great option to lower the eye pressure and/or reduce the need to take eye drops, if you suffer from ocular hypertension (high eye pressure but without damage to the optic nerve) or glaucoma, especially at the early stages of the disease. If you experience side effects from eye drops or would prefer not to have to take so many drops to control the eye pressure, the iStent may be an option for you. The procedure can be carried out at the same time as cataract surgery or as a standalone procedure.
This tiny device is placed into the eye’s drainage system, thus creating a bypass between the front part of the eye and its natural drainage system to restore the eye’s natural ability to drain fluid and lower the eye pressure. We use the iStent inject, which is the 2nd generation iStent device and is a double stent, providing optimum results in lowering eye pressure.
SLT uses a laser that works at very low levels to stimulate the drainage tissues of the eye and improve drainage. SLT could be a relatively safe option for you to lower the eye pressure and/or reduce the need for eye drops, especially if you have ocular hypertension (high eye pressure but without damage to the optic nerve) or early to moderate glaucoma. You may be suitable for SLT as a first line treatment for your glaucoma prior to considering treatment with eye drops. SLT could also be used alongside eye drops to further lower the eye pressure and therefore negate the need to add another eye drop to your existing regime.
This laser treatment may be indicated if you have closed or very narrow drainage angles. Normally fluid inside the eye flows behind the iris (coloured part of the eye), then forward through the pupil and leaves the eye through the ‘drainage angle’, which is located in the corner between the cornea (clear window at the front of the eye) and the iris this was taken from the internet). In some eyes the angle can be narrow, which can prevent the fluid from draining out of the eye and lead to a rise in the eye pressure or rarely to acute angle closure, a potentially sight threatening eye emergency associated with severe pain, redness, reduced vision and very high eye pressure. Using laser we can make a small hole in the iris, which in many cases helps to open the drainage angles, thus improving your long-term eye pressure control and preventing acute angle closure by allowing the fluid inside your eye to better access the drainage channels.
If your drainage angles are narrow or closed, you may benefit from cataract surgery not only in terms of improving your vision but also opening the drainage angles. This is because the plastic clear lens inserted in the eye at the time of cataract surgery is less bulky than the natural lens being removed, thus creating additional space within the eye and allowing the drainages angles to open. This may help to lower your eye pressure and/or reduce the need for glaucoma eye drops. At the time of cataract surgery we can sometimes offer an additional treatment called goniosynechiolysis, a technique to strip the peripheral anterior synechiae (PAS) from the drainage angle and provide the fluid inside the eye easier access to the drainage channels, thus further improving your long-term eye pressure control.
If your glaucoma is getting worse despite having tried drops and other less invasive modalities to lower the eye pressure (such as SLT or iStent), conventional surgery may be required. Trabeculectomy is a commonly performed surgical glaucoma procedure which lowers the eye pressure by making a small hole in the eye wall and allowing fluid from inside the eye to drain under the surface of the eye (conjunctiva) forming a reservoir (bleb).
The hole is covered by a trapdoor created in the wall of the eye which is sutured in such a way to prevent fluid from draining from the eye too quickly. You may be a good candidate for this procedure if you require a low eye pressure (around 10, with the normal range being 10 to 21 in the general population) to prevent your glaucoma from progressing, as a low pressure is unlikely to be achieved only with drops, SLT or the iStent. Mr Lascaratos has extensive experience in this field and the implications of surgery and of no surgery will be discussed with you during the consultation. Close follow-up is required after this type of surgery especially in the first 4 weeks. A successful trabeculectomy can offer you good eye pressure control to prevent further glaucoma progression and stabilise your vision often without requiring any glaucoma drops. For more information please click here.
An aqueous shunt or tube is a tiny device that is used to lower the pressure inside the eye. The device is made up of a small silicone tube (less than 1 mm in diameter) attached to a plate.
The silicone tube is usually inserted into the front of the eye (anterior chamber) allowing the aqueous humour to bypass the blocked drain of the eye (trabecular meshwork), thus lowering the eye pressure. The fluid drains through the silicone tube to the plate, forming a small blister (bleb) under the upper eyelid. You cannot see the bleb. Tube surgery may be an option for you if previous trabeculectomy or other glaucoma surgery has failed to control your glaucoma or if you suffer from a specific type of glaucoma (such as neovascular glaucoma) where trabeculectomy surgery is less likely to succeed. You may also be a good candidate for tube surgery if you are at risk of hypotony (very low pressure) with trabeculectomy surgery for example because you are very short-sighted (myopic) or because of your eye condition (such as uveitis). Tube surgery can be a safe and successful surgical option in these cases and overall requires less frequent post-operative interventions and less close follow-up comparing to trabeculectomy. For more information please click here.
You may be suitable for this type of laser especially if your glaucoma is difficult to control. While the other treatments mentioned lower the pressure by allowing more fluid to escape from the eye (increase outflow), this laser is different in that it reduces the fluid produced by your eye (decrease inflow) by being applied to the part of the eye (ciliary body) where fluid is normally produced. This can be a safe and effective way to lower your eye pressure if previous glaucoma surgery has been unsuccessful or you would like to avoid or delay the need for incisional surgery. You may also wish to consider this type of laser if the condition of your eye makes you a poor candidate for incisional surgery, or to provide pain relief if your pressure is significantly raised and your vision is poor.