**Core Concept**
Trachoma is a chronic keratoconjunctivitis caused by the bacterium Chlamydia trachomatis. It is a major public health concern in many developing countries, leading to blindness if left untreated. The disease primarily affects the cornea and conjunctiva, causing inflammation and scarring.

**Why the Correct Answer is Right**
Trachoma is characterized by its effects on the ocular surface, including the formation of trichiasis, entropion, and corneal opacity. The disease progresses through five stages, including the presence of chronic follicles, scarring, and eventually, corneal ulcers and blindness. The correct answer is the option that does not describe a potential complication of trachoma.

**Why Each Wrong Option is Incorrect**
**Option A:** Trichiasis is a common complication of trachoma, where eyelashes grow inward and rub against the cornea, causing pain and vision loss. Therefore, this option is incorrect because trichiasis is a known effect of trachoma.
**Option B:** Entropion is a condition where the eyelid turns inward and rubs against the cornea, which can be caused by trachoma-induced scarring. This option is incorrect because entropion is indeed a potential complication of trachoma.
**Option C:** Corneal opacity is a result of trachoma-induced scarring and is a major cause of blindness worldwide. This option is incorrect because corneal opacity is a known effect of trachoma.

**Clinical Pearl / High-Yield Fact**
Trachoma is the leading cause of preventable blindness worldwide, with an estimated 1.9 million people suffering from the disease. The World Health Organization (WHO) has launched a global initiative to control and eliminate trachoma by 2020.

**Correct Answer: D.**