Eye Exam Procedure
Our optometrist will start by asking you various questions such as your reason for your visit, is it a routine check, or whether you have some concerns regarding your vision. For instance you may have noticed your vision becoming blurred or you may be getting frequent headaches. We will also need to know about your medical history, what medication you are taking if any and any past or existing eye disorders. It is also important for us to know about any close relatives with eye problems, as some disorders such as glaucoma are hereditary. To enable us to advise you best, it will be helpful to know your occupation, lifestyle and hobbies. For example a retired person who plays a musical instrument may well need a separate pair of spectacles to be able to read the music score, whereas an engineer will need protective eyewear for work. If you already have spectacles then please bring them with you so we are able to make any comparisons with our findings.
The examination with an ophthalmoscope, known as an internal eye examination, lets our optometrist view the inside back of the eye, usually known as the fundus, whereby we can view the retina, the blood vessels, the optic nerve and macula. Observation of the retina can show tears or detachments if the blood vessels are enlarged or even leaking and if you are diabetic whether there is any structural damage. Where the optic nerve enters the back of the eye any indication of swelling or damage can be seen. Changes to the macula may also be visible and can be monitored. At the same time we can look at the crystalline lens for cataract. The crystalline lens is responsible for the eyes focussing ability, which decreases with age.
Moving on to the slit lamp, known as an external examination, out optometrist will be looking at a magnified image of the front surface of the eye, checking for red eye and the clarity of the cornea and the anterior chamber, which lies behind the cornea and in front of the iris. We are looking to se if the media looks cloudy, or if there are cells present, which could be an indication of inflammation or if the chamber is narrow an indication of glaucoma. At the same time we will also check your eyelids and surrounding area to make sure there are no problems.
Once we have completed our physical examination of the eye we will see how your eyes move around, it can be easily apparent if the eyes move smoothly and both eyes work together by getting you to follow a moving target. A cover test may also be done, especially on children to discover if either eye has a turn. By covering an eye and getting you to look at an object, our optometrist is able to see if the two eyes are properly aligned. Further checks may be done upon our findings.
The assessment people remember the most is what is known as refraction, where we put various lenses in front of the eyes and get you to read down the letters on a chart. Why people remember this the most, is we think, because people are worried that they have given us the wrong answers. For instance when we ask the question “ is it better 1 or 2? ”, however there is no need to worry as all the comparisons you make are double checked to make sure that your answers are consistent. At Paul Lewis Optician we use a computerised program loaded onto a laptop, with the letters viewed on a flat screen on the opposite wall. The program allows us to vary the order of the letters (so you can’t memorise them!), change to pictures for children and also do other checks such as contrast sensitivity, whereby the blackness of the letters changes and is useful for the assessment of cataracts. Using the letter chart, often known as a Snellen chart, we can gauge how well you can see both with and without spectacles and can give you a comparison with your existing glasses if you wear them. A prescription for your glasses, should you need them, is made after careful consideration by your optometrist having taken into account all their findings.
For adults over the age of 40, we will also screen for glaucoma using 2 types of assessment. Firstly we will check your visual fields on a machine called a Dicon 400. On this machine you will be asked to look at a red spot of light and follow it as it moves around a screen inside what is best described as a hollow box. Whist staring at the red spot a number of green lights will be flash on. The lights will number between 1 and 4 and can vary in brightness. By pressing a switch for the number of lights that you see, the machine can build up a picture of how well your brain interprets what you are seeing and because the green lights also very in brightness, how sensitive your vision is, can be recorded. By studying the results from this field test we can determine if you have any blind spots in your vision or glaucoma for instance. As a secondary check for glaucoma, the internal pressure of the eye is measured using a instrument called a tonometer. We have 2 types of tonometer at the practice, a non contact tonometer which puffs a gentle puff of air onto the front of the eye and measures the rebound effect. The puff of air doesn’t hurt but it does make you jump with surprise when it happens. The other type of tonometer is a contact tonometer. Before taking the measurements we need to put anesthetising drops onto the eye. The tonometer presses a flat probe against the front of the eye, the cornea, and measures how much pressure is needed to make the cornea flatten. If we couple the field test and the pressure readings with the results of the internal examination we are able to decide if there is a risk of glaucoma and will if necessary refer you to see a suitable specialist at the hospital.
Finally your optometrist will discuss their findings with you and advise you with their recommendations. You will be given a copy of your prescription for glasses or contact lenses if you need them and will be advised when your eyes should next be examined. It is recommended that adults be seen every 2 years and young children annually. Naturally there are exceptions to this and you will be told if you need to be seen more frequently, or if you feel your eyes have changed you can always come back sooner.
Should you need either spectacles for the first time or a change in spectacles our registered Optician will be able to advise you on suitable frames and lenses and also answer any questions you may have about your eyewear.
Once the consultation has been completed, you will be required to pay for your eye examination, which is currently £25.00. However certain people are entitled to a free NHS sight test. Call us on 01604 792930 and we will be able to tell you whether or not you may be eligible for a free test.