Final answer:
An Oil-Drop cataract is characterized by an oval, opaque irregularity. Light is dispersed or diffused by the cataract, and parallel laser light is required for precise repair of the retina.
Step-by-step explanation:
The characteristic appearance of an Oil-Drop cataract is d) Oval, opaque irregularity. This type of cataract resembles the shape and texture of a drop of oil, as the name suggests. A cataract itself is a cloudiness in the lens of the eye, which results in the scattering of light, causing vision to become blurred or less colorful. Also, due to cloudiness, light is dispersed or diffused as it passes through the cloudy lens.
The necessity for laser light to be parallel when spot-welding the retina during repair is due to the precise nature of the procedure. It is crucial that the laser light is focused accurately to ensure that the retina is reattached properly without causing damage to surrounding tissues.
Furthermore, in the case where the eye's lens is removed, a spectacle lens of about 16 diopters is typically prescribed to aid in focusing light onto the retina, compensating for the lack of the eye's natural lens.