Having an eye exam is one of the best steps you can take to protect your vision. Eye problems are most treatable when they are detected in their early stages, and regular eye exams can pick up eye defects in the very early stages. Regular eye tests can also give the optometrist a chance to correct and adapt your vision, and give you expert tips on caring for your eyes and reducing eye strain.
There are a number of different eye doctors. Opticians are the professionals who fill prescriptions, fit, assemble and sell glasses, and fit and sell contact lenses. Optometrists can evaluate vision, provide corrective lenses, diagnose common eye disorders and treat selected diseases, while ophthalmologists can deal with more complex eye problems and any eye conditions that require surgery.
A full eye exam incorporates a battery of tests which are designed to evaluate vision, and check for disease in your eyes. Eye exams don’t hurt, though there may be some bright lights, odd-looking instruments, and looking through what seems like hundreds of lenses!
The examination normally begins with the medical professional asking questions about any problems that you might currently be experiencing with your vision, and about your general medical history. The next stage involves a quick check with lights to ensure that the outside parts of the eyes are functioning normally. Following this, your visual acuity, need for glasses, and signs of disease will be assessed.
The tests which are carried out, include:
Eye muscle test – By observing your eyes as you track a moving object such as a pen in six specific directions, the medical professional looks for poor control or weakness of the eye muscles.
Visual acuity test – This is the best known of all eye tests. The optomometrists asks you to identify different letters printed on a chart which is positioned 20 feet away, with the lines of letters getting smaller and smaller down the chart. This test is completed with both eyes. This measures how clearly you see from a distance. 20:20 vision is defined as being able to read at 20 feet what the average healthy person would be able to read at 20 feet
Refraction assessment – This test helps the doctor to determine the lenses which will give you the sharpest vision and is only required if you need corrective lenses. It basically requires you to look through a mask-like device, called a Phoropter, which contains a range of different lenses. The doctor will then judge which combination of lenses results in the sharpest vision.
Visual field test – This tests for any areas in your peripheral vision in which you may have difficulty seeing. There are a number of ways in which this can be done, all of which involve you indicating when you can see a particular object in your vision.
Slit-lamp examination – Using a microscope, called a slit lamp, which illuminates and enlarges the front of the eye, the doctor can examine the cornea, lens, iris and anterior chamber of the eye. An eye drop, which contains an orange fluorescein dye, may be used in this stage to highlight any tears, cuts, scrapes or foreign objects on the cornea. The dye will be washed away by the eye’s teardrops.
Retinal examination – This examines the back of the eye. The eye is dilated with special drops, which may cause a medicinal taste in the mouth and sting briefly, before the exam is carried out. The exam may involve a direct or indirect examination. It may take some time for the effect of the drops to wear off, and your vision may be blurred for hours after the test. This blurred vision may prevent you from driving, so it will be necessary to have alternative means of getting home from the exam arranged.
Glaucoma test – Glaucoma can be detected through tonometry which measures intraocular pressure. Glaucoma, which can be treated if caught early, causes pressure build-up inside the eyes and is a disease which can result in blindness. Depending on which test is used, dyes and anaesthetic eye drops may be involved.
There is little to worry about regarding an eye exam. Apart from some minor discomfort caused by the drops used and bright lights, there is no pain.