Retinal detachment surgery is huge surgery and each case different. It is not possible to generalize. Your best source of information comes from your surgeon. Often 'only time will tell' and it takes 6 months or more to get the final result. Laser and this type of surgery and the underlying conditions like vitreous traction and posterior vitreous detachments often cause flashes of light but generally very bright and very short duration, think flash of lightening at midnight. So your description of a light flashing continually for 45 minutes is not typical of retina problem. This surgery does not cause migraine but in migraine patients can be a trigger for an acute migraine to occur. You should discuss with your surgeon.