Hi, I'm Scott Hebert, and I've just started taking Aikido lessons here in Columbus, Ohio, and I've hit something of a snag. I'm 24, and about 8 years ago, I was told I either have or am at high risk for retinal detachment (normally can be caused by concussion or other serious head injury). The head sensei at the dojo I have been taking lessons is wisely refusing to let me continue lessons until he has a professional opinion that it is relatively safe for me to continue training (naturally, aikido is not totally safe, but he wishes to know exactly at what greater risk I am in). If anyone could give me information specifically about retinal detachment and the likelihood of its occurrence in practicing aikido, I'd greatly appreciate it. Please email me privately if possible. Thank you for your time.