Finger tip pushups

[Blarg]

It is written up in books I've read that harsh fingertip work can harm the eyes. I'm afraid I'm proof of that. I trained my hands by thrusting them in sand, but particularly my right hand. Within a matter of months after doing this, my vision became a little more blurry in my right eye than my left. I now have very poor night vision in my right eye. It's quite dramatic. Especially since I'd always had extraordinarily good night vision before.

This all happened more than 20 years ago, so as far as I know there have been no further ill effects. I've long since given up the practice.

However, I also did a lot of fingertip push-ups, not in a tigerclaw style, but on the pads of the fingers, for years before I started training my fingertips with impact and hard contact. These fingertip push-ups I did and continued to do for many years, before and after, in great volume. I've noticed no ill effects.

[Hephaestus]

quoting Shaolin Long Fist Kung Fu by Dr. Yang:

Although the Iron Sand Hand is a great possession it has one great drawback. The martial artist who goes beyond eight to ten stages will become sterile. According to acupuncture theory, the nerves in the hand can influence the reproductive organs (the testicles) if enough stimulus is given to the hands. It is clear that the training methods can easily do this. Usually, martial artists who already have children or are permanent bachelors will go beyond the eighth or tenth stage." (25)

You might want to pick this book up. It's pretty much completely awesome.

If my understanding is correct, the eighth-tenth stages of Iron Sand Palm training involve jabbing the hands/fingers into red(hot) sand, and possibly even more drastic methods.
The Cheung, Ku-Yu method of Iron Palm does not involve these practices, thus falls below the eighth-tenth stages of Iron Sand Palm, thus with proper instruction and restraint of the ego, should not have the aforementioned effect of sterility, according to Dr. Yang.
The Cheung, Ku-Yu method of Iron Palm involves, if I recall correctly, only the bean bag, the gravel bag, and the steel shot bag, possibly with some supplementary Qigong practice, and traditional liniment (to prevent swelling and/or bruising) as well as an herbal wash formula (not the expensive and highly poisonous herbs associated with the highest stages of Iron Sand Palm training).
It should also be mentioned that many practitioners of this style of Iron Palm have fathered children long after beginning their Iron Palm training (such as Lam, Kwong Wing and several of his students.)
If anyone has even an indirect contact with Sifu Wong Jack Man, it would not hurt to ask his opinion/experiences and those of his students, as they train the same BSL lineage as Wing Lam (that of Cheung, Ku Yu), though I don't know if WJM or his students practice Iron Palm.