H49.1: Fourth [trochlear] nerve palsy
Muscles around the eye control eye movement. These muscles receive signals from the brain in order to perform these movements. These signals are transmitted by nerves. Some muscles in the eye have additional functions. They include lifting the eyelids and narrowing the pupils.
In your case, a nerve controlling the eye muscles is damaged. This kind of damage means that the eye muscles stop working normally and that you can no longer move the eye properly. The affected eye may be pointing down when looking straight ahead or to the side, for example. You may also have double vision. For some people, double vision gets better when they turn their head in a certain direction. These people may often hold their head tilted to one side.
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If you see an ICD diagnosis code (e.g., on a medical report), be aware that doctors may also include additional indicators to express diagnostic certainty. Only a healthcare professional can interpret these codes accurately in the context of your individual case.
For a complete understanding of your condition and what the diagnosis means for you, please speak directly with your doctor.