Why dont eye doctors apply fish gall on patients to cure cataracts?

Why don't they make mud with spit and apply it to the eyes of blind men like Jesus did? I'm not familiar with the book of Tobit because it's not in my Bible. I have to assume that if this story is recorded there, it is a record of some miracle. There is no a recipe for getting miracles. God in His sovereignty gives them when it is in His perfect plan to do so. The record of miracles in the Bible is not a recipe for how to duplicate the results.

Cataracts are inside the eye, so nothing applied to the surface can cure them.

What “Blind Tobit” most likely had was pterygium. That’s where the conjunctiva (the mucosal membrane covering the front of the eye) grows thickened and can cover the iris with a white membrane which obscures vision much like a severe cataract.

The fix these days is to surgically remove the membrane and to allow it to regrow naturally without the defect.

Nobody would use it today, but bile (gall bladder secretions) are corrosive. So it may be that some ancient folk-healers used a corrosive process to kill the pterygium or to adhere to it so that it could be peeled off. Either process would be agonisingly painful.

Modern medical science has a far better understanding of the causes of pterygium and the best remedies. So there’s nothing to be gained by rubbing fish guts onto eyes and hoping for a fix. The experiments to test that idea would likely cause serious harm to far more living eyes than they’d ever fix, so the experiments would be not merely unwise but totally unethical.

What balderdash

Because it's so easy to replace them with plastic that gives the patient 20/20 vision.