Tenotomy is a surgery that is performed to correct nystagmus. Nystagmus occurs where eyes display voluntary or involuntary movements. It is acquired at infancy and is known to cause blurry or reduced vision. The condition makes it impossible for an individual to keep their eyes focused on any particular object. The purpose of tenotomy is to slow down the involuntary eye movements to ensure that the eye takes a more detailed picture.
Tenotomy corrects nystagmus through the removal of selected muscles of the eye and attachment to the eyeball at the same spot. Tenotomy interferes with the electric signal between the brain and eye muscles resulting in a reduction of these involuntary eye movements. Tenotomy is often performed on bicep muscles, tendons, and ankle joints.
Also Known As
- Tenotomy of horizontal eye muscles
- Four muscle surgery
- Horizontal rectus tenotomy
Before the Procedure
The capability of both eyes to observe the same item as a single image and generate a perception of depth (stereopsis) in humans matures at the age of about three months. Therefore, for effective attainment of binocular vision and the capacity to recognize an image three-dimensionally, surgery of the eye muscle should not be done after four years of age. Performing the surgery earlier increases the chances of a better outcome.
Patients should ensure that the doctors have information concerning any medicine that they are taking, including over the counter drugs. About ten days before surgery, patients should avoid aspirin or alternative blood-thinning medication. As in most surgeries, the patient should not take any food or drinks after midnight before surgery.
Tenotomy to correct nystagmus is done while the patient is under anesthesia. It involves two horizontal muscles of each eye. The eye doctor makes an incision in the loose tissue that covers the eyeball surface (conjunctiva) and the muscle is disconnected from the white outer layer of the eyeball (sclera). The muscle is then reattached at its initial point of insertion. The procedure's main objective is to ensure that the frequency and length of eye movement are reduced, ultimately improving visual action.
The actual techniques through which this procedure corrects for involuntary eye movements are not explicitly known. However, tenotomy is a modification of an earlier procedure that was performed and designed to maintain a straight posture for patients with rapid, involuntary repetitive eye movements who had to turn their heads for maximum visual acuity.
Risks & Complications
Specialist advisers have asserted that the following effects are likely to be manifest:
- Need for a revision surgery
- Damage to the eye
- Occurrence of infection
- Worse alignment of the eye
- Double vision
- Damage to the retina
- Rapture of the globe
- Loss of vision in very rare cases
Aftercare & Recovery
After the surgery, patients need someone to drive them home. The patient's eyes may have a scratchy feel and may feel some mild pain after the operation. The scratchiness should fade away after 14 to 21 days.
Some minor swelling may also appear after surgery. Nonetheless, it gradually disappears in about two days and patients can open their eyes.
The patient should avoid medications such as aspirin for about three days. S/he should discuss with the doctor on appropriate medications to aid in recovery.
In about three days, the pain should reduce and the patient can get back to normal activities. However, the recovery period varies from one person to another. Patients should therefore consult their surgeon on the appropriate time to get back to normalcy.
After the procedure, there is broadening and lessening of the eye movements which allows for improved vision. Relevant studies on the efficacy of tenotomy have shown on average that there is an increase in visual acuity in about 50% of treated patients. That is, there is an increase in a patient's ability to identify details of objects seen. However, for 50%, there is no notable change in visual acuity.
An assessment in patients who underwent tenotomy shows that nine out of 10 patients had a significant increase in the ability to fix their eyes on an object. However, one out of ten had a decrease in their ability to fix their eyes on an item. On average, the change in the ability to fixate eyes on an object increased by 43%.
Visual specific mental health is also used as a measure to assess the efficiency of the tenotomy procedure. After one year of undergoing the procedure, the evaluation of patients showed an increase in overall visual questionnaire scores among 90% of the patients. However, one patient recorded a lower score after the procedure.
The assessments indicate high efficacy levels from the tenotomy procedure; hence it can be advised for patients with visual problems as a result of rapid involuntary eye movements.