Bowling by persons who are blind is not only possible but is also highly competitive. Just ask anyone in the American Blind Bowling Association [1] or at the International Blind Sports Association [2] about tournaments, training, and rules!
Blind and visually impaired athletes can compete in bowling through one of two adaptive methods: sighted guidance or a guide rail.
When using the sighted guidance method, a sighted assistant aligns the blind bowler on the approach before the delivery. The bowler is aligned on the spot from which he or she wishes to execute the delivery. The reference point can be a particular board on the approach, for example.
Guide rails can help with both your approach and delivery. These lightweight tubular metal rails are easy to assemble and can help guide you straight toward the pins. They can be assembled, disassembled, and stored easily. Some alleys or bowling centers have guide rails already in place or available for loan.
Links:
[1] http://www.visionaware.org/abba
[2] http://www.visionaware.org/international_blind_sports_association
[3] http://www.visionaware.org/sports_exercise
[4] http://www.visionaware.org/sports_groups
[5] http://www.visionaware.org/find_recreation_sports_leisure_products