This is not an exhaustive list of eye conditions that may affect a child’s vision. For more information on children’s eye conditions, please get in touch with Vision Ireland today.
The colour of our skin depends on how much melanin is in it. Melanin is a dark brown material (pigment) found in many parts of the body. The body parts that it helps colour include the skin, hair and eyes. Some children cannot make as much melanin as others and some cannot make any melanin at all. Children who do not make as much melanin as normal have Albinism. Most children with Albinism only have a problem making melanin in their eyes. These children have ‘Ocular Albinism’. In other children the lack of melanin affects all parts of the body as well. They may have pale skin and blonde hair with light coloured eyes. These children have ‘Oculo-Cutaeneous Albinism’.
Cataract is when the normally clear lens of the eye becomes hazy. If the lens is not clear then not all the light can get into the eye and vision is often blurred.
Cataracts can affect different children in different ways. Cataract usually causes blurring of vision. The more hazy the lens is the more blurred the vision will be.
Most children with cataract in only one eye usually have good vision in the other. These children do not normally complain of reduced vision. If both a child’s eyes have cataracts they are much more likely to have serious visual impairment.
If only a small area of the lens is hazy, away from the centre, then the child is likely to have good vision. If the centre of the lens is very hazy, not letting much light in, then the child is more likely to have poor vision.
If cataract has been present from an early age then the child may develop ‘lazy’ eyes. This is also known as Amblyopia. It is not actually the eye that has become lazy; it is the special vision parts of the brain. The brain can only learn to see as clearly as the picture given to it by the eyes. If the brain has not been given a sharp, clear picture by the eye because of cataracts then it cannot learn to see clearly. If the cataracts are removed by an operation vision may still be blurred. This is because the brain has not developed the power to see clearly. This is called Amblyopia.
Some children with cataract also sometimes have other problems with their eyes. Microphthalmia and nystagmus are often seen along with cataract in children. These other eye conditions may cause reduced vision even though the cataracts have been removed. If you would like information on nystagmus or microphthalmia please ask.
3. Optic Nerve Hypoplasia
When a baby is growing in the womb sometimes not all of the parts of the eye grow correctly. If a part of the eye does not grow to its full size this is known as hypoplasia. If the part of the eye does not grow at all then this is known as aplasia.
Optic Nerve Hypoplasia is a condition present from birth in which the eye does not have all the usual wiring between the eye and brain to transfer information about the visual world. The loss of wiring can sometimes be only very small but sometimes can be complete with no information being transferred from the eye to the brain at all. One or both eyes can be affected.
Optic Nerve Hypoplasia can affect vision in different ways. If only a small number of wires in only one eye have failed to grow and the optic nerve is almost normal then the child may also have normal vision. If both optic nerves have almost completely failed to grow properly then the child will have reduced sharpness of vision and may only see bright lights and large shapes. If only a part of the optic nerve does not grow correctly then only a part of the visual world will be missing with the rest almost normal. Sometimes children can develop fast to-and-fro movements of the eyes (nystagmus) if vision is very poor. Squint can also develop.
Retinitis Pigmentosa is the name given to a wide range of eye conditions. ‘Retinitis’ means disease or inflammation of the retina. ‘Pigmentosa’ refers to how the retina can look in this condition (the retina can often develop lots of small, dark specks of pigment). Retinitis Pigmentosa eye conditions are all linked by a problem with the rod and cone photoreceptors. The photoreceptors either work poorly from the day a child is born or else slowly stop working over a period of time. Usually the rods are affected more than the cones. Some Retinitis Pigmentosa conditions do not only affect the eye but may also affect the rest of a child’s body.
Some older children may begin to notice that their vision is blurred around the edges and their vision is especially poor in the dark. These children might have a problem mainly with their rod photoreceptors.
Some other children may notice that their central vision is becoming increasingly blurred and that most colours are not bright. These children may mainly have a problem with their cone photoreceptors.
Some other children may end up only seeing bright lights or the movement of large objects. These children may have problems with both cone and rod photoreceptors. Sometimes in adulthood cataracts can develop. Cataract is when the normally clear lens of the eye becomes hazy. If the lens is not clear then not all the light can get into the eye and vision is often blurred. This can be treated by an operation. The hazy lens is removed and replaced by a clear plastic one.
Stargardt disease is sometimes called a juvenile macular dystrophy as it can first appear between the ages of 10 to 20. However, Startgardt disease can also begin later than this.
At first Stargardt disease will make your vision unclear and then sometimes distorted or blurred. You may have problems with your central, detailed vision and possibly colour perception. If you have had Stargardt disease for a number of years then you may have a blank patch in the centre of your vision. This blank patch will not move and will always be in the very centre of your field of vision.
Stargardt disease does not usually affect other parts of your retina so does not normally affect peripheral or side vision. Since you use your peripheral vision when you are moving around, most people with Stargardt disease can manage to keep getting out and about on their own.
Stargardt disease can also cause problems such as glare and difficulties adapting to changing light conditions.