Final answer:
Operating on a newborn with a unilateral congenital cataract is crucial to improve vision, prevent further vision loss, and reduce the risk of complications, hence 'All of the above' is the correct answer. It also prevents permanent vision impairment due to a critical period of vision development.
Step-by-step explanation:
It is important to operate on a newly born baby with unilateral congenital cataract to achieve multiple objectives: 1) To improve the baby's vision, 2) To prevent further vision loss, and 3) To reduce the risk of complications, effectively making the answer 4) All of the above. If the cataract is not treated early, it can result in permanent vision impairment or blindness, due to the deprivation of visual input necessary for the development of the visual cortex. This is comparable to experiments with kittens where deprivation of visual input from one eye caused alternative neural connections to form, which essentially overlooked the input from the affected eye. Moreover, cataracts can lead to a disruption in the visual development of infants, as they scatter or diffuse light that is supposed to pass clearly through the eye's lens.
When correcting vision after cataract removal, an internal intraocular lens can be implanted to provide perfect distant vision. However, the ability to read without glasses depends on whether the intraocular lens also corrects for the individual's near vision, which can vary. For example, if the person was nearsighted before the surgery, the power of the intraocular lens will be less than that of the natural lens that was removed to compensate for the original refractive error.