Ever since I started my university training, I’ve been acutely aware that the general public have absolutely no idea how much is involved in an eye examination. That is no particular surprise to me. Eye care is woefully undervalued in this country, with many patients kicking up a stink at the cost of an eye examination, whilst thinking nothing of spending dramatically more on dentistry, physiotherapy; car mechanics…the list goes on. Now I’m not criticising those professions in anyway, just making the point that whilst their professional know-how is accepted, somehow eye care is stuffed under the carpet. With that in mind, and since this is naturally a subject close to my heart, I thought I would explain some of the tests that make up an eye examination.
I’m often asked in faintly incredulous tones “How long did it take you to learn all this?”. I completed a 3 year undergraduate degree in Optometry. That’s three whole years just studying eyes, so highly specialised training. After the degree, I completed what we call a pre-registration year, which is a little like an apprenticeship. I spent a year working in practice (or you can chose a hospital) with the general public, with a supervisor checking all my work. A minimum number of eye examinations and contact lens fits and aftercares must be undertaken during that year, and 20 case studies prepared. At the end of the year I took 10 nerve-wracking Professional Qualifying Exams, which were all either practical, oral, or both.
For an NHS-funded eye examination, an Optometrist is contractually obliged to check the health of your eyes, and your spectacle prescription. Beyond those stipulations, it is down to the conscientiousness of your Optometrist which tests they do or don’t perform. “Pfft, but that’s all there is to it!” I hear you scoff! Not so! Allow me to bore you by explaining some of the more commonly encountered tests within my arsenal.
History and Symptoms
Judging by their reactions, a few patients obviously think I’m just being a Nosey Parker! Whilst not meaning to be disrespectful, knowing that John Doe takes prostate medication isn’t how I get my jollies. Your Optometrist needs to know your state of general health because a large number of seemingly irrelevant general conditions (anaemia, high blood pressure, diabetes, over-active thyroid, HIV, I could go on…) can impact directly on your ocular health. Likewise a vast number of commonly prescribed medications (steroids, anti-depressants, HRT, the list is endless) can have ocular side effects which we need to check for.
Self explanatory, but I will add that it is not necessary for a patient to be literate. In my favourite consulting room I also have a chart of Es and Cs of varying orientations, a chart of numbers, and a chart of pictures.
Motility, Accommodation, NPC & Pupil reactions
Motility assesses the function of the 6 muscles that control eye movements. Accommodation measures the ability of the lens within your eye to alter its shape to focus on a near target (an ability which steadily decreases with age), and the near point of convergence measures the ability of the eyes to turn in towards the nose, to point at an increasingly close target. Pupil reactions are the eyes’ ability to react to changes in light level, and are affected by a number of disorders.
This is a measure of how well your eyes work together as a team. The brain receives one image from the right eye, and a second image from the left, and then has to stick to two together. In certain cases, the eyes don’t work together well enough to enable “binocular vision”, and the patient will either experience distressing double vision, or in milder cases, eyestrain and/or headaches.
The measurement of the strength of spectacle lenses required to give you the clearest vision possible. Whilst refining the prescription with the patient’s preferences is preferable, it can be measured with a retinoscope without any response from the patient.
Slit lamp & Ophthalmoscopy
A Slit lamp is essentially a microscope giving a dramatically magnified view of the eye to check for any anomalies, and an ophthalmoscope is used to view the inside of the eye. I am frequently asked what I’m looking for during ophthalmoscopy, and the answer, without wish to be facetious, is “anything abnormal”. My “bible” of eye diseases is an A4 book of approximately 2 inches thick. Your Optometrist is checking for signs of any of those diseases, and any changes from previous eye examinations, which might be indicative of early disease. Anyone who visits a different company for each and every eye examination is actually compromising the quality of their eye care, since there is no benchmark with which to compare findings.
Fields and Pressures
The dreaded puff test! The puff of air measures the pressure inside the eye, by, to put it crudely, measuring how squishy your eyeball is! This is one of the tests we use to detect glaucoma. The field of vision test checks your peripheral vision, which is affected by any number of conditions.
This is by no means an exhaustive list (I have more weapons in my arsenal than the infamous Q-branch!), but covers my “core range” as it were, with various other tests being indicated during history and symptoms, or depending on the individual patient.