Accommodation is the ability of the eye to focus (by adjusting the lens) to maintain a clear image as objects move closer. Poor accommodation means that the eye is having problems doing this due to hyperopia, myopia or, more likely, presbyopia (age related lens hardening which means it hasn’t the same range of movement as before).
Also known as ‘lazy eye’. Decreased vision in one or both eyes without detectable anatomic damage to the retina or visual pathways. Usually uncorrectable by eyeglasses or contact lenses.
Astigmatism is when the cornea (the clear cover over the iris and pupil) is more half-rugby ball shaped than the spherical, half football shape it is meant to be. The effect on the vision is to stretch out the image viewed in the area that the bulge occurs. Sometimes the brain can compensate for astigmatism although it may be too strong for this to happen without the aid of glasses.
Clouding of the lens is known as cataract. It can be present from birth (congenital) or can develop later in life. They are usually progressive, so require regular monitoring.
Corneal opacities mean that the cornea, which is normally clear, has become opaque for one of a number of reasons such as dystrophy (degeneration) or scarring or cloudiness caused by dehydration or over hydration.
Also known as hypermetriopia, is long sightedness. When a person is long sighted, this means that they can see objects, which are further away more easily than those which, are nearer to them. Most people will have glasses that they need to wear for reading, watching TV, table top activities etc. This is because the eyes struggle to focus at all distances and this, if uncorrected, can lead to eyestrain.
Intra Ocular Pressure
Increased pressure within the eye. eg Glaucoma.
This is a degenerative condition where the cornea thins and is pushed outwards, usually in the centre, by the internal pressure of the eye. Usually this is hereditary, occurs in both eyes and appears in the teens. It is associated with conditions such as Downs Syndrome. If untreated, it can result in a rupture, but sometimes it may stop in an earlier stage of if its development or simply not progress that far. It is a condition which requires to be regular monitoring. In mild cases, spectacles will offer correction of the refractive problems. Contact lenses may be required for more advanced cases.
Myopia is short sightedness. This means that the eye has difficulty when focussing on more distant objects, so glasses should be worn when prescribed.
This is a condition where the eye moves almost constantly. It can either be vision related or due to muscular imbalance. If vision related, it often indicates deterioration in the central field of vision, such as macular degeneration or loss of central vision. It occurs as the eye is relying largely on rod cells in the peripheral retina which require movement to focus on an object or else it will fade out. If the object is not moving then the eye will move as it attempts to keep the object in focus.
This is a refractive condition in which the accommodative ability of the eye is insufficient for near vision work due to ageing.
Usually results from a head injury. Optic disc appears raised above the level of the retina.
A strabismus is basically a squint. The main effects of a strabismus are that usually the person will have one eye which is stronger than the other. This is because the brain has to give priority to one eye over the other with the result that the weaker one does not ‘learn’ to see as well as the stronger one. In practical terms, a person should be guided from their weaker side to allow them to make full use of their stronger eye, but in contrast, should be approached from or have objects presented to their stronger side.