This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adverse Ocular Effects of Systemic Drugs, Subject name: Ophthalmology
Thyroid eye disease is due to - 
Select and explain. 
A. Thyrotoxicosis, B. Hypothyroidism, C. Euthyroidism, D. Hashimoto's disease
A: Thyrotoxicosis
Answer: A: Thyrotoxicosis 
Explanation: Ans. is 'a' i.e., Thyrotoxicosis o Thyroid eye disease (TED) is also known as Grave's ophthalmopathyo Among patients of TED:# 90% - Thyrotoxicosis# 6% - Euthyroidism# 3% - Hashimoto's disease# 1% - Hypothyroidism