## Core Concept
The Vision 2020 initiative, launched by the World Health Organization (WHO) and the International Agency for the Prevention of Blindness (IAPB), aims to eliminate avoidable blindness by the year 2020. It focuses on major causes of blindness and visual impairment, and includes strategies for their prevention and treatment.

## Why the Correct Answer is Right
The Vision 2020 initiative primarily targets diseases and conditions that are major causes of avoidable blindness, such as cataract, refractive errors, glaucoma, diabetic retinopathy, and age-related macular degeneration. It emphasizes comprehensive eye care services, including prevention, diagnosis, treatment, and rehabilitation. The initiative's focus is on diseases and conditions directly related to vision loss.

## Why Each Wrong Option is Incorrect
- **Option A:** Cataract is a leading cause of blindness worldwide and is included in the Vision 2020 initiative as a major target for intervention.
- **Option B:** Diabetic retinopathy is another major cause of blindness that Vision 2020 aims to address through early detection and treatment.
- **Option C:** Glaucoma is a group of eye conditions that damage the optic nerve, and it is a focus area for Vision 2020 due to its potential for causing irreversible blindness if not treated.

## Why Option D is Correct (Implicit)
Since the question asks for "all except," and given that options A, B, and C are all major causes of blindness targeted by Vision 2020, option D must represent something not directly included in the main goals of Vision 2020.

## Clinical Pearl / High-Yield Fact
A key aspect of Vision 2020 is its emphasis on comprehensive eye care, including the management of refractive errors, which are a common cause of visual impairment. Another important point is the initiative's focus on strengthening eye care services in developing countries, where the burden of avoidable blindness is often highest.

## Correct Answer: D.