Oculocardiac, Vasovagal reflexes, and Contact Lens Wear
For an optometrist, nothing is more horrified than his or her first-ever encounter of patient suddenly lost consciousness and collapsed soon after inserted a contact lens on the eye.
As the episodes of patient fainted just few minutes after putting on contact lens have not been described in the relevant textbooks, when confronted with such situation, optometrists may be caught by surprise or panicked for how to manage a suddenly fainted patient.
My first encounter of this situation was an active young adult with constant spectacle wear requested an eye check for contact lens wear, mainly for sports.
He has no known medical history. His ocular parameters and health were insignificant. Inserting contact lenses on him to evaluate lens fit and performances without much difficulty, despite his excessive reflex blinking and small aperture fissures. He was extremely delighted to the comfort and the realistic visual perception with the trial contact lens correction.
During pre-delivery instruction on lens insertion and removal, he had a big difficulty to overcome his involuntary blinking. He has to repeatedly held on his eyelids firmly to enlarge his aperture fissure and unintentionally inserted the lens forcibly on his eye. Eventually he successfully placed the lens on his eye but just few minutes later he passed out and collapsed on the floor. He looked pale, skin felt cold. However, his breath remained stable and a regular pulse rate of 28/30sec. The contact lens was immediately removed from his eye, and he regained consciousness spontaneously in about a minute since he fainted and resumed normal activities after about 15 minutes.
In another episode which was a thirteen years old boy, whose mother requested to have disposable contact lenses for his sports activities. The mother reported he is (and he appeared to be) a healthy boy. Routine clinical examination showed no contra-indication for contact lens wear. Just few minutes after the first trial contact lens was inserted without difficulty, he initially appeared pale and daze, and then fainted on the examination chair. The trial contact lens was immediately removed and his cardinal signs were monitored closely. Very quickly the boy regained full consciousness spontaneously.
His mother confessed that her son did test and try to wear Ortho-K contact lens in another country and he passed out soon after the trial contact lens was inserted, and regained consciousness in about a minute.
Syncope or fainting, is the result of transitory cerebral ischemia. This fall in blood supply to the brain is caused by the autonomic nervous system ceased functioning properly by an external trigger, such as sitting or standing up suddenly, scary or unpleasant sight, sudden pain etc. These external triggers may also lead to bradycardia resulting temporary inadequate blood supply to the brain. Oculocardiac reflex can occur from traction on extraocular muscles or compression of the eyeball resulting reduced heart beats and inadequate blood flow to the brain.
There are numbers of reports of healthy patients fell unconscious soon after contact lens was inserted and all of them recovered consciousness within ten minutes. When confronted by such situationss, most important is to ensure patient has normal breathing, maintaining normal circulation, remove contact lens immediately, monitoring closely until patient regained consciousness, and advise only to leave after full recovery. Some of them after careful retry to wear contact lenses, avoiding forcibly lens insertion and excessive compression on the eyes, they can wear contact lenses without any problem.