Forums.NitroExpress.com

This from a Wikipedia artical on Retinal Detachment:

"There are some known risk factors for retinal detachment. There are also many activities which at one time or another have been forbidden to those at risk of retinal detachment, with varying degrees of evidence supporting the restrictions.

Cataract surgery is a major cause, and can result in detachment even a long time after the operation. The risk is increased if there are complications during cataract surgery, but remains even in apparently uncomplicated surgery. The increasing rates of cataract surgery, and decreasing age at cataract surgery, inevitably lead to an increased incidence of retinal detachment.

Trauma is a less frequent cause. Activities which can cause direct trauma to the eye (boxing, kickboxing, karate, etc.) may cause a particular type of retinal tear called a retinal dialysis. This type of tear can be detected and treated before it develops into a retinal detachment. For this reason governing bodies in some of these sports require regular ophthalmic examination.

Individuals prone to retinal detachment due to a high level of myopia are encouraged to avoid activities where there is a risk of shock to the head or eyes, although without direct trauma to the eye the evidence base for this may be unconvincing.[5] Some doctors recommend avoiding activities that increase pressure in the eye, including diving, skydiving, again with little supporting evidence. According to one medical website, retinal detachment does not happen as a result of straining your eyes, bending or, heavy lifting.[14] Therefore, heavy weightlifting would appear to be fine. However, two recent scientific articles [15][16] have noted cases of retinal detachment or maculopathy due to weightlifting (specifically with the Valsalva method), and a third documented an increase in blood pressure in the eye during weightlifting [17].

Activities that involve sudden acceleration or deceleration also increase eye pressure and are discouraged by some doctors. These include bungee jumping[5] and may also include rollercoaster rides."

In my opinion, recoil energy is less of a factor than recoil velocity. Two rifles may have the same recoil energy, but one may have much higher recoil velocity, due primarily to insufficient weight in respect to the cartridge used. I think that recoil velocity in excess of 25 fps. is too great for the average shooter to accomodate to and may have dire consequences in the long run.