Final Answer:
Cataract is considered an emergency when it causes sudden vision loss, severe pain, or trauma.
Step-by-step explanation:
Cataracts typically progress slowly, but certain circumstances can turn them into emergencies.
Sudden vision loss may indicate complications such as a rapidly developing cataract or other issues like a retinal detachment, requiring urgent attention. Severe pain in the eye associated with cataract can signal complications like inflammation or increased intraocular pressure, demanding immediate medical evaluation.
Additionally, traumatic injuries to the eye that result in a cataract may necessitate emergency intervention to address both the cataract and associated damage to the eye structures.