Question:
how is cataract induced glare explained? What is the cause?
Answer:
I don't think you mean "cataract induced glare". I think you mean "How is
post-cataract surgery increased light sensitivity explained". If it were
caused by the cataract surgery, it could be from several factors. The
easiest explanation is that prior to the surgery the patient probably had
several years of decreased light reaching the retinas (due to the cataract
itself), and got used to this lower level of illumination. Post surgery the
patient not only has all that "fog" lifted, but now has an artificial lens
that is even more transparent than a perfect human lens, so things will be
WAY brighter under all levels of illumination.
But it also could be something as simple as damaged epithelium from poor
surgical technique, which would increase photophobia as well.