**Core Concept**
Thyroid eye disease, also known as Graves' ophthalmopathy, is a complex condition that involves inflammation and tissue expansion of the orbital tissues. This condition is closely associated with autoimmune thyroid diseases, particularly Graves' disease.

**Why the Correct Answer is Right**
Thyroid eye disease is primarily caused by the autoimmune response to thyroid antigens, which leads to the production of autoantibodies that stimulate the orbital tissues. The activation of T cells and the production of cytokines, such as interferon-gamma, contribute to the inflammation and tissue expansion in the orbit. The increased levels of thyroid-stimulating immunoglobulins (TSI) and thyroid-stimulating antibodies (TSAb) stimulate the orbital tissue to proliferate and grow, leading to the characteristic symptoms of thyroid eye disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately represent the primary cause of thyroid eye disease.
**Option B:** This option is incorrect as it refers to a different condition, orbital cellulitis, which is an infection of the orbital tissues.
**Option C:** This option is incorrect as it refers to a different condition, orbital pseudotumor, which is a non-specific inflammatory process in the orbit.

**Clinical Pearl / High-Yield Fact**
Thyroid eye disease is often associated with the severity of Graves' disease, with more severe eye disease correlating with more severe thyroid disease. Early recognition and treatment of thyroid eye disease can help prevent long-term complications, such as vision loss and disfigurement.

**Correct Answer: D. Autoimmune response to thyroid antigens.**