Final answer:
Signs of cataracts include blurry vision, night vision difficulties, light sensitivity, seeing halos, double vision, and changed prescriptions. Prevention involves protecting eyes from UV-B rays with plastic sunglasses. Treatment typically involves lens replacement surgery, with cataract-induced cloudiness dispersing light entering the eye.
Step-by-step explanation:
Signs of Cataracts and Related Concepts
Cataracts are characterized by clouding of the lens in the eye, which leads to a decrease in vision. The signs of cataracts typically include blurry or foggy vision, difficulty with vision at night, sensitivity to light and glare, seeing 'halos' around lights, frequent changes in eyeglass or contact lens prescription, double vision in a single eye, and fading or yellowing of colors. Cataracts are one of the leading causes of blindness and are responsible for 50% of all cases. Age is a significant risk factor, with 60% of individuals between 65 and 74 years old developing cataracts. However, repeated exposure to UV-B rays is also a contributing factor. To prevent the formation of cataracts, wearing protection such as plastic sunglasses that block UV rays is recommended.
Once cataracts have developed, treatment involves the surgical replacement of the clouded lens with a plastic lens. This procedure is typically straightforward and successful. Concerning the physics of how cataracts affect vision, a cataract disperses light entering the eye, as opposed to diffusing it, causing the blurriness and other visual impairments associated with this condition. When surgeons use laser light to repair a tear in the retina, they require the rays to be parallel as they enter the eye to ensure precise focus on the targeted area.
If an individual has had the lens of their eye removed because of cataracts, a spectacle lens of about 16 diopters (D) will likely be prescribed to compensate for the loss of the natural lens's focusing ability.