White part of my eye turning a faint yellow colour, why?

Iiver disease. This could be a manifestation of liver disease cause icterus. I recommend seeing a doctor as soon as possible.
Sun damage . This probably is a pingueculum which forms from sun exposure. At the histological level it is basophilic degeneration. You should wear sunglasses to minimize exposure not only to the eyes but also the eyelids which can also get skin cancers.