OCULAR MANIFESTATIONS OF THYROID DISEASE

1. OCULAR MANIFESTATIONS OF THYROID DISEASE

2. Graves ophthalmopathy • Other names: thyroid eye disease, thyroid orbitopathy • Autoimmune inflammatory disorder whose underlying cause continues to be elucidated • Signs and symptoms may progress and abate independently of other clinical features • Eye findings may occur even in the absence of objective evidence of thyroid dysfunction (euthyroid Graves disease)

3. Graves ophthalmopathy • Ophthalmopathy may relate to antibodies that cross-react with TSH-R antigens expressed on orbital fibroblasts

4. PATHOGENESIS: • Theories: • Glycosaminoglycans expressed from fibroblasts causes secondary water retention and therefore, retrobulbar swelling • TSH-R as the antigen

5. Fusiform enlargement of extraocular muscles; sparing of tendons

6. Little enlargement of extraocular muscles but marked increased in the orbital fat may occur.

7. Diagnostic criteria for Graves ophthalmopathy

8. Key points about Grave’s disease: • Most common cause of eyelid retraction • Most common cause of bilateral or unilateral proptosis. • More common in women • Associated with hyperthyroidism in 90% of patients; 6% are euthyroid • Smoking is associated with increased risk and severity of ophthalmopathy. • The course of ophthalmopathy does not necessarily parallel the activity of the thyroid gland or the treatment of thyroid abnormalities.

9. Grave’s disease/Thyroid Ophthalmopathy Clinical signs • Eyelid retraction- most common sign • Lid lag • Proptosis • Restrictive extraocular myopathy • Optic neuropathy

10. Other clinical features: • Most frequent ocular symptom is pain or discomfort (30%)- often the result of dry eyes • Diplopia- 17% • Lacrimation/photophobia- 15-20% • Blurring of vision- 7.5%

11. Non-ocular clinical findings: • Thyroid dermopathy- 4% • Thryroid acropachy-1% • Myasthenia gravis- 1%

12. A. Bilateral proptosis and upper eyelid retraction B. Marked chemosis, eyelid swelling and increased proptosis

13. Bilateral lid retraction • Bilateral lid retraction • No associated proptosis • Bilateral proptosis • Unilateral lid retraction • Lid lag in downgaze • Unilateral proptosis

14. Soft tissue involvement Periorbital and lid swelling Conjunctival hyperaemia Superior limbic keratoconjunctivitis Chemosis

15. Proptosis • Occurs in about 60% • Uninfluenced by treatment of hyperthyroidism Axial and permanent in about 70% May be associated with choroidal folds Treatment options • Systemic steroids • Radiotherapy • Surgical decompression

16. Optic neuropathy • Occurs in about 6% • Early defective colour vision • Usually normal disc appearance Caused by optic nerve compression at orbital apex by enlarged recti Often occurs in absence of significant proptosis

17. Restrictive myopathy • Occurs in about 40% • Due to fibrotic contracture Elevation defect - most common Abduction defect - less common Depression defect -uncommon Adduction defect - rare

18. Treatment: • Correction of thyroid function abnormality- • Anti-thyroid drugs • Radio active iodine • thyroidectomy • Orbital decompression- to treat optic neuropathy, orbital congestion, advanced proptosis • Topical ocular lubricants • Corticosteroid treatment • Orbital radiotherapy- targets lymphocytes?

19. Treatment and Prognosis: • Self limiting, but…. • may run an active course of exacerbation and remissions • Therapy directed toward decreasing orbital congestion and inflammation or expanding the bony volume

20. Treatment and Prognosis: • Often improves with establishment of euthyroid state, but eye disease may continue to progress • Elective orbital decompression, strabismus surgery and eyelid retraction repair usually are not considered until a ophthalmic signs have been stable for 6-9 months.