MYOPIA, HYPEROPIA & PRESBYOPIA
In short, the definition of myopia (short-sightedness) is where the eye is longer than normal or the cornea is too steep, meaning that light rays focus in front of the retina. Near objects are clear, but distant objects appear blurred. For the most part, this is an inconvenience considering how frustrating it can be to be dependent on contact lenses or spectacles. In addition, eyes with a high degree of myopia are at an increased risk of developing a serious condition like retinal detachment or glaucoma.
In short, the definition of hypermetropia (long-sightedness) is where the eye is shorter than normal or the cornea is too flat, meaning that light rays focus behind the retina. Light rays from close objects such as pages of a book cannot be focused on clearly by the retina. Someone with hypermetropic eyes may find their vision is blurred when looking at objects near to them, and for vision to be clearer when looking at far away objects.
Placing a plus-powered (convex) lens in front of a hypermetropic eye allows the image to be moved forward allowing for correct focus on the retina. A degree of long-sightedness is common in many people, although this only presents a problem when our ability to see is significantly affected or where headaches and eye strain are common.
Definition of presbyopia
When we are young, the lens in the eye can change its shape allowing us to focus on near objects. After the age of 40, the lens becomes noticeably more rigid and reading at close range becomes increasingly difficult. This condition is defined as presbyopia and is a normal part of ageing.
What are the symptoms of presbyopia?
Presbyopia is usually first noticed by difficulties reading in low light. Often, you may find it will take longer for eyes to refocus from reading to distance and from distance to reading. Spectacles may be required to give additional focusing power to the eye as reading proves more problematic.
The distance of reading dictates which power you would require. For example, looking at a computer screen will require a different power for reading a book. We will ask you about your lifestyle and take this into account when prescribing your reading addition to ensure clarity of vision for the required visual task.