Graves’ ophthalmopathy,
CHAPTER 4
Graves’ ophthalmopathy
40Damage to the eye can be confi rmed with a fl uorescein or rose Bengal stain.
Fundoscopy should be performed to rule out papilledema. Proptosis may result in periorbital edema and chemosis because the displaced orbit results in less effi cient orbital drainage.
Persistent visual blurring may indicate an optic neuropathy requiring urgent treatment. Severe conjunctival pain may indicate corneal ulceration requiring urgent referral.
Features are unilateral in approximately 15% of cases.
Investigation of proptosis
The NOSPECS classifi cation is not universally accepted; for detailed classi-fi cation see www.EUGOGO.org and The European Group on Graves’
Orbitopathy. 1
Documentation using a Hertel exophthalmometer
The feet of the apparatus are placed against the lateral orbital margin as defi ned by the zygomatic bones. The distance between the lateral angle of the bony orbit and an imaginary line tangent to the most anterior aspect of the cornea is recorded.
A normal result is considered <20 mm (<18 mm in Asians, <22 in Afro-Carribeans). A reading of 21 mm or more is abnormal, and a difference of 2 mm between the eyes is suspicious.
Soft tissue involvement
Soft-tissue signs and symptoms include conjunctival hyperemia, chemosis, and foreign-body sensation.
CT or MRI scan of the orbit
This demonstrates enlargement of the extraocular muscles, which can be useful in cases of diagnostic diffi culty. This is also more accurate for dem-onstration of proptosis.
Examining for possible ophthalmoplegia
Patients may complain of diplopia due to ocular muscle dysfunction caused by either edema during the early active phase or fi brosis during the later phase. Assessment using a Hess chart may be helpful.
Intraoptic pressure may increase on upgaze and result in compression of the globe by a fi brotic inferior rectus muscle. Ocular mobility may be restricted by edema during the active infl ammatory phase or by fi brosis during the fi brotic stage.
The two most common fi ndings are defective eye elevation caused by fi brotic contraction of the inferior rectus muscle, and a convergence defect caused by fi brotic contraction of the medial rectus. Disorders of the medial rectus, superior rectus, and lateral rectus muscle produce typi-cal signs of defective adduction, depression, and abduction, respectively.
1 The European Group on Graves’ Orbitopathy (2006). Clinical assessment of patients with Graves’ orbitopathy: recommendations to generalists, specialists and clinical researchers. Eur J Endocrinol 155(3):387–389.
04-Draznin-Chap04.indd 40 3/31/2011 2:35:17 PM
GRAVES’ OPHTHALMOPATHY 41
Examining for possible optic neuropathy
History of poor vision, a recent or rapid change in vision, and poor color vision are reasons for prompt referral. A visual acuity of <6/18 warrants referral to an ophthalmologist.
For color vision, each eye should be evaluated using a simple 15-plate Ishihara color vision test. Color vision is a subtle indicator of optic nerve function. Failure to identify >2 of the plates with either eye is an indication for referral. This is unhelpful in the 8% of men who may be color blind.
Marcus Gunn pupil: The “swinging fl ashlight” test detects the presence of an afferent pupillary defect.
Medical treatment See Box 4.1.
Lid retraction
Most patients do not require any treatment, as clinical signs usually improve with treatment of hyperthyroidism or spontaneously with time (40%).
• Sunglasses help with photophobia and excess tears.
• In patients with signifi cant lid retraction and exposure keratopathy, topical lubricants improve symptoms (surgery to reduce the vertical lid fi ssures can be considered).
• Botulinum toxin injection may reduce upper lid retraction.
• Head elevation during sleep and diuretics may help congestion.
• Tape eyelids at night to avoid corneal damage Active ophthalmopathy threatening sight
• Glucocorticoids at high doses (e.g., prednisone 60–80 mg/day) improve ophthalmopathy in 60–75% of cases.
• Effectiveness of glucocorticoids is more likely in those with diplopia at neutral gaze and an infl ammatory component to ophthalmoplegia.
• Treatment should be given for 2 weeks and then tapered gradually.
• Urgent referral to an ophthalmologist is indicated for any suspicion of optic neuropathy or corneal ulceration.
Orbital radiotherapy
• Indications for lens-sparing orbital radiotherapy are similar to those for high-dose glucocorticoids.
• Radiotherapy probably works by reducing the activity and number of activated T lymphocytes in the retrobulbar tissues.
• 20 Gray administered in 10 doses of 2 Gray over 2 weeks • Treatment with both radiotherapy and glucocorticoids is more
effective than either alone.
• Effectiveness in 60% of patients <40 years of age Other medical therapies
• Other immunosuppressive regimens have no proven place in the general management of Graves’ ophthalmopathy.
• Use of depot octreotide has been shown to be of no benefi t in management.
04-Draznin-Chap04.indd 41 3/31/2011 2:35:17 PM
CHAPTER 4
Graves’ ophthalmopathy
42Surgical treatment See Box 4.1.
Surgery for decompression
• Orbital decompression may be indicated for urgent treatment of optic neuropathy.
• Posteromedial wall of orbit is usually removed.
• Complications include dysmotility of the eye, blindness, orbital cellulitis, cerebrospinal fl uid (CSF) leak, cerebral hematoma, obstruction to nasolacrimal fl ow, and anosmia.
Surgery for strabismus
• Should be performed after any necessary orbital decompression • Aims are to allow correct binocular vision
• Performed when eyes are in a quiescent phase for at least 6 months after active disease
• Involves alteration, loosening or tightening of eye muscles, often over several operations, to improve binocular vision.
Eyelid surgery
This is the fi nal stage of any surgical approach. The aims are to adjust the upper and lower eyelid position to improve comfort and appearance.
Box 4.1 Treatment of Graves’ ophthalmopathy General measures
• Smoking cessation
• Dark glasses, with eye protection • Control of thyroid function Specifi c measures
Problem Treatment
Grittiness Artifi cial tears and simple eye ointment Eyelid retraction Tape eyelids at night to avoid corneal damage.
Surgery if risk of exposure keratopathy Proptosis Head elevation during sleep
Diuretics
Systemic steroids
Radiotherapy
Orbital decompression
Optic neuropathy Systemic steroids Radiotherapy Orbital decompression Ophthalmoplegia Prisms in lenses in the acute phase
Orbital decompression
Orbital muscle surgery
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THYROID ACROPACHY 43