It takes time to check your eyes thoroughly, carrying out all the tests to ensure your eyes are healthy and to investigate any symptoms you’re having. Most important is the time to explain the results of your eye exam and to discuss any concerns you may have regarding your eyes. That’s why we allow 40 minutes for a standard eye exam at Aves.
What does an eye examination involve ?
History and symptoms: The optometrist will ask various questions about your eyes and your health to gather information specific to you. This allows the eye examination to be individual to your particular needs. You will be asked for details of any medications that you are taking, as some drugs and medical conditions can affect your eyes. You may want to bring a list of your medications with you. We will ask about any history of eye problems that you may have had along with details of relevant medical and eye problems in your close family.
Vision: It is important to check how well you currently see, either with existing spectacles or without any spectacles.
Spectacle prescription: this will tell us whether or not you need spectacles to help you see comfortably.
Muscle balance: this tells us how well your two eyes are working together. Visual comfort is very important and a muscle balance problem can cause significant eye strain.
Ophthalmoscopy: this torch-like instrument enables us to examine the eyes to ensure that they are healthy.
Volk lens examination: this lens gives us a 3D view of the eye, helping us check your eyes in even more detail.
What else might be done?
Tonometry: this measures the pressure within the eye. It is one of the tests for glaucoma and is typically carried out in patients over the age of 40.
Visual fields: this measures peripheral vision and is a useful screening test for glaucoma as well as many other eye related problems. We have invested in the very best visual fields instrument which allows us to carry out specialist visual field assessments typically used in hospital investigations.
Colour vision: this detects colour vision defects and is typically done at a child’s first visit.
Stereopsis: this measures binocular vision by means of 3D pictures and is often carried out as part of a child’s eye examination.
Slit lamp biomicroscopy: this enables a magnified view of the front surface of the eye. It is particularly useful in contact lens work and dry eye assessment.
Keratometry: this measures the shape of the front surface of the eye and is used extensively in contact lens fitting.
Optical Coherence Tomography (OCT)
Until fairly recently, we have been able to examine your eyes using a variety of instruments, all of which show us what is going on at the surface of the retina. This has enabled us to detect and diagnose a wide variety of eye conditions such as glaucoma, age related macular degeneration and diabetic retinopathy, to name but a few. OCT is an amazing new piece of technology which allows us to go one step further. In a few seconds, the OCT safely and painlessly scans the back of the eye, providing a 3D view through and beneath the retina. The information provided by OCT scans enables us to detect and diagnose a wide variety of eye conditions at the very earliest stage.
OCT and Glaucoma
Glaucoma is a common eye condition, which for many years has been associated with high pressure in the eye. But detecting glaucoma is much more complicated than simply measuring eye pressure and modern definitions of glaucoma do not even mention eye pressure.
Glaucoma is an eye disease that causes a progressive loss of nerve fibres from the optic nerve and retina, resulting in a gradual loss of vision. This process is usually slow and painless and the loss of vision often does not become apparent to the individual until very advanced (when up to 90% of the nerve fibres have already been lost). Such damage to the optic nerve cannot be repaired and so it is imperative to detect glaucoma at the earliest possible stage so that suitable treatment can be initiated to prevent further visual loss.
The OCT allows us for the first time to actually measure, with incredible accuracy, the thickness of the nerve fibre layer in the retina and optic nerve head. The instrument can then compare this result for any individual with the result for a ‘normal’ optic nerve to indicate whether nerve fibres have been lost and therefore whether glaucoma may be present. By repeating his measurement at subsequent eye examinations it is possible to detect subtle changes to the nerve fibre layer which may indicate the very earliest sign of glaucoma. Current estimates suggest that OCT detects early stage glaucoma 3 years earlier than conventional pressure measurements and/or visual fields assessments.
OCT and Diabetic Retinopathy
In diabetic retinopathy, the growth of abnormal new blood vessels leads to leakage from these vessels and subsequent damage to the retina. The OCT is able to detect leakage within the retina and below the retina as well as leakage visible on the surface of the retina. This means that diabetic retinopathy can be seen, even when it’s not visible using digital retinal photography.
OCT and Age Related Macular Degeneration (AMD)
Many people have heard of the eye condition AMD which causes blurring and/or distortion of the central part of vision, affecting an individual’s ability to see detail such as print or people’s faces. AMD can lead to complete loss of central vision and it is now the leading cause of blindness in the UK.
There are two types of AMD: wet and dry. Dry AMD is much more common than wet and thankfully it affects vision less. There is currently no effective treatment for dry AMD but there are ways of halting or slowing down the progression of it – see our patient information section on AMD. Many people may have signs of dry AMD for many years without any serious effect on their vision.
A minority of people develop wet AMD. This involves the development of abnormal new blood vessels underneath the macula (the central part of the retina) which then (as the name implies) leak fluid into the retina. Over a very short period of time this can cause distortion and severe loss of central vision. In recent years great strides have been made in developing effective treatments for wet AMD.
Whenever we examine your eyes, we are always looking for signs of AMD and particularly any signs that could indicate the presence of wet AMD. The OCT allows us to see underneath the macula, to the area where new blood vessels or fluid leakage may occur. By detecting these signs at a very early stage, treatment can be initiated quickly to stabilise the condition and prevent loss of vision.
So who should have OCT?
We recommend that anyone with specific concerns about glaucoma, AMD or diabetic retinopathy has an OCT scan at each visit for an eye examination. We will advise you whether that should be every year or every two years depending on your individual risk factors or concerns.
An OCT is also useful for early detection of ocular signs in many systemic health conditions, such as multiple sclerosis, raised blood pressure and cancer.
To get a complete picture of the health of your eyes, we recommend an OCT scan for all adults, particularly anyone over 40 years old, as increasing
age is a significant risk factor for both glaucoma and AMD.
Have a look at this YouTube link to see what OCT involves:
Diabetic Eye Care
Many of you will know that the NHS provides Diabetic Retinopathy Screening for all diabetic patients. This involves digital retinal photography carried out by a technician in the local area. The photographs are then examined by a trained observer who will look for any signs of diabetic retinopathy. We recommend that you attend this NHS screening. However, diabetic retinal screening does not provide a full assessment of your vision and eye health and it is therefore important that you continue to attend for regular eye examinations.
We are, of course, happy to continue to examine your eyes specifically for signs of diabetic retinopathy and this will include 3D digital retinal scans as well as digital retinal photographs. At the end of this examination we will send a report to your own doctor. A fee is charged for this service.
This does not affect your entitlement to an NHS eye examination.
Specialist glaucoma screening
Glaucoma is notoriously difficult to diagnose and many people are referred to the eye department at their local hospital as a result of high pressure readings at the opticians, only to find that they do not have glaucoma.
At Aves, we have invested in equipment, mainly used in hospital eye departments, to help improve our ability to find glaucoma. OCT scans are now recognised to be the most effective way to detect glaucoma at its earliest stage (see section on OCT and glaucoma). An OCT scan can detect glaucoma up to 3 years earlier than any other clinical test. We therefore recommend regular OCT scans for anyone at risk of glaucoma. Raised eye pressure can be a factor in detecting glaucoma. As well as the commonly used ‘air puff’ procedure for measuring pressure in the eyes, we also have a gold standard tonometer, as used in hospitals, for more accurate pressure readings. If your pressure readings are high, we will always measure them again, using this more accurate device. Recent research has shown that eye pressure can be linked to corneal thickness, and that particularly thin or thick corneas are likely to give ‘false’ pressure readings. Hospitals now regularly measure corneal thickness, using a specialist instrument, called a pachymeter, to see if unusual corneal thickness is affecting the pressure readings. We are also able to offer this additional service at Aves, enabling us to be more precise in our interpretation of your eye pressures.
Visual fields are a measurement of peripheral vision, and are useful in diagnosis of glaucoma, as peripheral vision is affected long before central vision in glaucoma. Hospitals use sophisticated visual field testing equipment, to discover the very earliest visual field loss in glaucoma and other eye conditions. Aves have also invested in this technology, in order to offer our patients the very best advice regarding risk of developing glaucoma.
Dry Eye Assessment and Therapy
Many people are troubled by the effects of dry eyes, particularly as they get older. Symptoms can range from mild irritation in certain dry or air conditioned atmospheres to persistent and debilitating soreness and blurred vision. The causes of dry eye are various. Sometimes there can simply be a lack of tears produced while in other cases it may be a problem in the quality of tears and possibly associated eyelid disease.
At Aves in Epping, we are able to carry out a full assessment of the tears and eyelids to determine the nature of any problem and to advise on the most suitable treatment.
In some cases where there is substantial tears deficiency, we can use punctum plugs to reduce the drainage of tears from the eye and so enhance the effectiveness of the patients’ natural tears. If our examination indicates that this may be an effective technique, temporary collagen plugs are used in the first instance. These dissolve over the course of about two weeks. If they prove effective at reducing symptoms during this time, then permanent silicone plugs may be fitted.
Low Visual Aids
We offer a wide range of magnifiers and visual aids designed to help patients with any visual impairment, when glasses alone are not sufficient. We are able to demonstrate many of these aids to patients, following a tailored visual assessment to find the most suitable device for each individual.