Convergence insufficiency is a problem of near vision. In this disorder, a person finds difficulty in seeing, reading nearby objects. In normal circumstances, the eyes turn inwards when you focus your sight on nearby objects. This means they converge. But in convergence insufficiency, the affected person is not able to move his eyes inwards to focus on nearby objects.
The disorder is often detected in early childhood and adolescence age. Often convergence disability is misdiagnosed and parents and teachers consider it as a learning problem in children, instead of a disorder related to the eye.
Symptoms Of Convergence Insufficiency
A person suffering from convergence insufficiency may experience following symptoms especially while he is working closely like reading, writing, working on the computer or desk work etc.
- The eyes become tired and sore easily.
- On and off headaches, especially while reading or focusing on near objects for a long time.
- Complaint of blurred vision or double vision.
- Due to difficulty in focusing, the child is unable to concentrate.
- Patient finds difficulty in reading. He may complain of words floating or swimming on the book.He may also lose his track while reading.
- Patient feels sleepy while working on nearby objects. It is due to strain on his eyes.
- He often closes one eye or squints. The person does so while reading to prevent double vision or blurred vision.
- He frequently tilts his head and has poor posture while doing work which requires near vision.
Lack of sleep, anxiety and working for long hours with objects placed nearby may exaggerate the symptoms.
Person suffering from convergence insufficiency finds difficulty in playing sports; he may find difficulty in judging nearby objects while driving etc.
Causes Of Convergence Insufficiency
The exact cause of conversion insufficiency is not known, however the reason behind it is misalignment of eyes. It is probably caused due to improper stimulation of eye muscles by the nerves. There is defect in electrical impulse and the eyes do not focus on a nearby object.
Injury to the head is another probable cause for convergence insufficiency. Head injuries can cause immense damage to the brain and the nerves arising from the brain.
A lesion in brain may be responsible for it. It can be a growth arising in the brain. This tumor can be cancerous or non cancerous. These benign or cancerous growths causes pressure on brain and interrupt proper functioning of neurological pathway.
Diagnosis Of Convergence Insufficiency
- Often the condition is missed or remains undetected by parents and teachers. Most people suffering from convergence insufficiency may have 20-20 vision. It is difficult to detect the condition while performing routine examination.
- Proper medical history is valuable in diagnosing this eye problem. Person may have complaints of blurred vision, headache, and worsening eyestrain even if the person reads for a short period of time.
- NPC is near point convergence test that may detect the disorder. In this simple test, the examiner holds a small object such as a pencil in front of the patient. The physician moves it closer to the patient till the patient complains of double vision.
- In positive fusion vergence, the patient is made to look at the eye chart through a prism lens. The doctor will know when the patient will have double vision.