What is Myopia?
Myopia is often referred to as "short-sightedness" or "near-sighted". An eye is myopic when the "far point"; a point at which light from an object is focussed on the retina, is located at a finite distance in front of the eye. Myopia can be due to either an eye which is too long relative to the optical power of the eye (axial myopia), or because the optical power of the eye is too high relative to the length of the standard eye (refractive myopia). The focus is correctly adjusted with a "minus" power lens, or concave lens.
Signs & Symptoms
Children with myopia commonly complain of blurred distance vision. Parents may also notice their child squint their eyes while viewing distance objects. If the degree of myopia is moderate or high, then children may be observed sitting closer to the television and computer or holding reading material closer. Patients with pathologic myopia may also report visual distortion secondary to retinal pathology.
How We Test for Myopia
Testing for myopia may use several procedures to measure how the eyes focus light and to determine the power of any optical lenses needed to correct the reduced vision. As part of the testing, we will ask you to identify letters on a distance chart. This test measures visual acuity, which is written as a fraction, such as 20/40. The top number of the fraction is the standard distance at which testing is performed (20 feet). The bottom number is the smallest letter size read. Our usual practice is to use our state-of-the-art OCT machine to measure the eye ball and then we are able to decide what type of Myopia Management is needed.
Myopia Management
Myopia is a global problem. The rising prevalence and the risks of sight-threatening ocular pathology associated with myopia are well documented. By 2050, it is predicted that half the world’s population will have myopia, with nearly one billion at high risk of sight threatening ocular pathology. In the UK, the prevalence of myopia in children aged between 10–16 years has more than doubled over the last 50 years, and children are becoming myopic at a younger age. Given this backdrop, it is crucial to begin to understand and tackle these issues head on.
Our Instruments
Using an instrument called a phoropter, we will place a series of lenses in front of your eyes and measure how they focus light using a handheld lighted instrument called a retinoscope. Or we may choose to use an automated instrument that evaluates the focusing power of the eye. The power is then refined based on your responses to determine the lenses that allow the clearest vision. We can conduct this testing without using eye drops to determine how the eyes respond under normal seeing conditions.
In some cases, such as for patients who can't respond verbally or when some of the eye's focusing power may be hidden, we may use eye drops. The eye drops temporarily keep the eyes from changing focus during testing. Using the information from these tests, along with the results of other tests of eye focusing and eye teaming, we can determine if you have myopia. We will also determine the power of any lens correction needed to provide a clearer vision. Once testing is complete, we will discuss treatment options.
How we use MYAH
The MYAH allows us to accurately collect data on non-invasive tear break up time, meibomian gland imaging with area of loss analysis and tear meniscus height measurements. It also features the ability to perform blink analysis, providing objective analysis of the blink characteristics of the individual. Imaging and video acquisition provide a tool that allows us to educate the patient. The reporting allows for visit-on-visit comparison to monitor the effect of therapy and allow more informed decisions when it comes to refining and adjusting treatment options.
The MYAH provides us with the information we need to operate specialist myopia management and dry eye clinics, knowing we can offer the most evidenced-based approach to our patients. In return, we can achieve our ultimate aim as a practice; to deliver the best outcomes we can for our patients.
Treatment
At our practice, we can treat these problems in many different ways using our state of the art technology and our professional team. One option we use for myopia in children is glasses. A concave lens is used to diverge the light rays entering the eye and place the focal point on the retina. Once children get a bit older, contact lenses then become an option. Patients should generally be in their pre-teen or early teenage years before considering contact lenses, however the decision is made for each patient based on their level of maturity.
In special circumstances, refractive surgery may be indicated for children with neurological impairment, neurobehavioural issues, facial deformities or severe anisometropia that render it impossible for glasses wear. Refractive surgery for the general population is usually only indicated once the patient has stopped growing which generally occurs in the late teens to early twenties.