The Assaf Resection Muscle Hook incorporates a double-armed squint hook with an integrated caliper, thereby allowing controlled muscle resection. This design allows the surgeon to isolate and hook the extra-ocular muscle with one arm of the instrument. The integrated caliper can be set to define the amount of muscle which needs to be resected. The caliper range is from 2mm to 14mm. The muscle is supported with the other arm of the instrument, without causing undue stretching or tension. A suture can be passed along the groove in the second arm in either an interrupted or conventional fashion.