A patient complains of yellow vision and an ophthalmologic exam reveals a central lens opacity that appears to have enlarged. The most likely diagnosis is which of the following?

• A. Cataract
• B. Pterygium
• C. Keratitis
• D. Glaucoma

Answer: (A)

A central lens opacity that enlarges with yellow vision points to a cataract. The lens becoming cloudy and taking on a yellow-brown hue is a classic sign of aging changes in the crystalline lens, and when the opacity is central and progressive, it directly impairs vision, causing blur and glare.

Pterygium is a conjunctival growth on the surface of the eye that can affect vision if it encroaches onto the cornea, but it does not cloud the lens itself or change color of vision. Keratitis involves inflammation or infection of the cornea, leading to pain and tearing with corneal opacity, not a lens opacity. Glaucoma affects the optic nerve and typically presents with peripheral vision loss and optic changes rather than a central lens opacity or yellow-tinted vision.

So the central, enlarging lens opacity with yellow vision best fits cataract.