Purpose: To report a rare case of spontaneous anterior dislocation of the crystalline lens in a patient with thyroid-associated ophthalmopathy and previous glaucoma attack.

Case summary: A 48-year-old female presented with sudden vision impairment of the right eye over three days. The initial slit lamp examination showed mild corneal edema and anterior dislocated crystalline lens in the right eye. The best corrected visual acuity was 20/63, and the intraocular pressure was 24 mmHg in the right eye. Patient had a history of peripheral iridotomy and argon laser peripheral iridoplasty due to acute angle closure in the right eye. Clear cornea lens extraction and scleral fixation of the intraocular lens was performed. The best corrected visual acuity was 20/20, and the mean intraocular pressure was 16 mmHg after the surgery.

Conclusions: Anterior dislocation of the crystalline lens can occur in a patient with thyroid associated ophthalmopathy and previous glaucoma attack. The possible mechanisms of dislocation of the lens are zonular weakness due to acute angle closure and high retrobulbar pressure by thyroid associated ophthalmopathy. This is the first report of anterior dislocation oflens in a patient with thyroid-associated ophthalmopathy.