Eye Examinations Explained

Different Types of Tests Explained

Pupil Reactions: using a pen torch we will assess how your pupils react to the light source. Your pupils should react together. If one pupil is unresponsive it is an indication to an underlying problem that will need to be investigated.

Cover Test: this test is used to see if the eyes work together as a pair. Using a small opaque plastic cover, we cover one eye at a time to check for a squint, also known as strabismus. A squint is when one eye turns and does not sit straight. The squint can be an eye that turns in, out, up or down. Some squints can also alternate between the eyes. If we detect a squint we will refer you to see a specialist in squints called an Orthoptist.

Confrontation Test: is a simple way to assess your peripheral vision. Using a target (usually red), we will assess how wide or far out you can see too. Confrontation is a simple version of a visual fields test. You will be asked to tell us when you can detect the chosen target, from an area outside your vision to an area where you should be able to see it.

Tonometry: is a test to check your eye pressure and is very quick to do. There are different types of tonometry instruments; here at eyedeal vision we like to use the gold standard version (Goldmann or Perkins applanation contact tonometer), which is favoured by Ophthalmologists. We begin by putting drops in your eyes. There are two drops used, a temporary numbing drop (anesthetic that only lasts for 10 minutes) and fluorescein (orange dye). We use either the Goldmann or Perkins tonometer to then measure your eye pressure. A Blue lit prism head is gently placed on the front of the eye, which then gives us your eye pressure reading. This test is painless.

Humphreys Visual Fields Analyzer: there are many different types of visual fields assessments that can be done according to your eye health or eye conditions you might have. Visual field tests are used to check that the retina (light sensitive layer at the back of the eye you use to see with) is functioning normally. Patients that have an eye condition or are suspect of having a particular eye condition will be recommended to undergo intensive visual fields tests that are tailored to them. With this test, usually one eye is covered, and we will ask you to look at a central amber light with the open eye. Whilst focusing on the amber light you will see small flashes of white light that are either very bright or very dim, every time you see one you are asked to click the buzzer. You will use your peripheral vision to detect the lights, it is important that you keep looking at the amber light. We will run a demo version of the test first to get you used the test and help you understand how the visual fields test works. Visual fields are checked in both eyes. This test is very useful in detecting early stage Glaucoma, assessing the health of optic nerves, checking your central vision (macula) and assessing other eye conditions.

The OCT Scan: is also known as Optical Coherence Tomography scan. We recommend everyone to have this additional test as it gives us valuable information about your eyes. This scan is non-invasive and uses light waves to see the layers of the retina and underlying eye tissue. When we look at the back of your eyes, we only see the top layer of the retina; the OCT scan allows us to see underneath the top layer of the retina. From this scan we can see any underlying eye problems and this will help us diagnose any eye conditions at an earlier stage. Early detection and rapid referral for eye conditions is paramount in saving sight! OCT scans are very useful in patients that have Glaucoma, suspect Glaucoma, family history of glaucoma, previous or suspect retinal detachments or tears, age related macular degeneration, family history of macula degeneration, any retinal diseases, any optic nerve head diseases and diabetes. The OCT scan can also be used to monitor your current diagnosed eye conditions too. NASA are currently using the same machine we use, the OCT scan is 4D, time being the fourth dimension.
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Pachymetry: is a test used to assess the thickness of the cornea. This is a useful indicator in the diagnosis & management of glaucoma. It is also measured before you have any invasive surgery such as laser surgery. We will use an anaesthetic eye drop and then gently place the Pachymetry probe head on the front of the eye for a few seconds; this will give us your corneal thickness reading. The cornea is the clear window at the front of your eye, the clear layer in front of the iris. This test is painless.

Gonioscopy: allows us to view the internal drainage angle and its components within your eyes. It is a painless test. The drainage angle sits between your cornea and iris, it is called the iridocorneal angle. Gonioscopy uses a goniolens (gonioscope) to view the drainage angle, we can use anesthetic drops to numb the front of the eyes and place the goniolens onto the cornea. We use the slit lamp to then view the anterior eye components and drainage through the goniolens. If the drainage angle looks narrow this can be an indicator for glaucoma. This test is also useful for anyone that has had an impact or contact injury to the eye, i.e. hit in the eye, which may have damaged the drainage angle.

Visionix: assesses the front of the eyes (anterior eye). The Visionix machine allows us to map the surface of your corneas, patients with corneal abnormalities or keratoconus are easier to monitor with this technique. We can also assess the anterior chambers of your eyes (anterior eye) a useful tool in glaucoma detecting and monitoring. Using the Visionix we can also measure patient’s corneal Aberrometry and measure your prescription, which is especially useful if someone is non-verbal. The Visionix is useful in Glaucoma, cataract, contact lens fittings and cornea assessments.
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Biohead Set: is a 3D way for us to view your retina. It gives us a very wide field of view of your retina. This is very useful in viewing the retina (light sensitive layer at the back of the eyes that allow you to see) as a whole and for us to check for very peripheral retinal tears, holes, degeneration or detachments. The optician will wear a headset and use a large lens to view the retina at the back of your eyes. We will use dilating drops to make your pupils large (dilation of your pupils) to ensure we have a good view.

Indirect Ophthalmoscopy: is a 3D technique using a slit lamp and lens. Here you will have your chin on the chin rest, the lens will placed in front but away from your eyes and the optician will look through the slit lamp to assess the retinas in both eyes. You may need to have your eye dilated if your pupils are too small. The field of view seen by the optician is slightly less than the bio headset, but still great for viewing the retina.

Direct Ophthalmoscopy: is a 2D technique used to view the retina in high magnification. We use an Ophthalmoscope to view the retina, this is non invasive and we get very close to you to perform the test.

DRS Retinal Camera: This is where we take photographs of your fundi (the retinas); here we take a visual record of the back of your eyes (more accurate then written notes). This is useful for comparison and detecting changes at the back of your eyes (retina) in your future eye tests & photographs with us. This camera is approved for diabetic eye screenings too, which we offer privately for anyone who does not want to go to the diabetic retinal screening eye clinic.
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