1. Eyelid retraction and retardation The eyelid sign of patients with thyroid-related ophthalmopathy is upper eyelid retraction, which has diagnostic value (eye position sign). The width of normal blepharoptosis is related to race, heredity and other factors. The middle part of the upper eyelid margin of normal adults is located between the upper edge of cornea and the upper edge of pupil, or 2mm below the upper edge of cornea. The middle part of the lower eyelid margin is flat on the scleral margin of the lower angle. If the upper and lower eyelid margins leave the above normal position, it is usually eyelid retraction or ptosis. In thyroid-associated ophthalmopathy, it is usually eyelid retraction, that is, the upper eyelid margin is raised, even reaching above the upper corneal margin, and the lower eyelid margin is below the lower corneal margin, exposing the sclera above or below the corneal margin. In eyelid retraction, upper eyelid retraction is more common. When the eyeball looks down, normal people. When patients with thyroid-associated ophthalmopathy look down, the adducted upper eyelid can not move down or slowly decline with the eyeball moving down, which is called delayed upper eyelid decline. Due to the involvement of Miao Lei muscle and levator palpebrae superioris muscle, the traction and descending function is poor. In addition, the eyelid swelling affects the function of the orbicularis oculi muscle to close the eyelid, so the patient's blink reflex is reduced and he stares. This is also a special sign, which is common in patients with thyroid-associated eye diseases, accounting for 35% ~. ② Adhesion of levator palpebrae superioris to surrounding tissues; ③ The lower eyelid contraction muscle adheres to the surrounding tissues. Small studied the levator palpebrae superioris muscle of normal people and 10 patients with thyroid-associated ophthalmopathy. Biopsy showed that muscle fibers were obviously thickened, tendons in some patients were slightly thickened, the gap between muscle fibers and muscle bundles was widened, and there were mild fibrosis, mucopolysaccharide deposition, mild focal inflammation and fat infiltration in the muscle gap, which were the pathological basis of upper eyelid retraction, delayed falling and swelling.
2. Patients with thyroid-associated ophthalmopathy have soft tissue involvement, inflammatory cell infiltration, blood vessel congestion and dilation, increased permeability and interstitial fluid, but the deposition of mucopolysaccharide in the stroma is obviously increased, and the tissue absorbs a lot of water. These two factors together make the eyelid and conjunctiva congestion turn red, and the eyelid, conjunctiva, lacrimal gland and orbital soft tissue swell. In patients with acute thyroid-associated ophthalmopathy or invasive exophthalmos,
(1) Eyelid congestion and swelling: Eyelid congestion and swelling are common, which are characterized by red color, fullness and thickening, disappearance of upper eyelid sulcus and congestion and swelling of upper eyelid. It can be divided into mild, moderate and severe. Eyelid hyperemia and swelling lead to poor eyelid mobility and inability to close, which is the main cause of exposure keratitis.
(2) Congestion and edema of bulbar conjunctiva: The local congestion of bulbar conjunctiva is mostly caused by vasodilation at the attachment of external rectus muscle, which has certain diagnostic significance. Usually, conjunctival congestion and edema occur on the temporal side or below, but also on the nasal side, which is relatively rare. The bulbar conjunctiva turns red and swollen due to severe congestion, protruding out of the palpebral fissure, which is another cause of exposure membranitis.
(3) Involvement of lacrimal apparatus: The lacrimal caruncle can be swollen due to congestion and edema, and the lacrimal gland can be swollen due to congestion and edema. Clinically, the lateral eyelid can be lifted, and the supratemporal fornix is swollen and the lacrimal gland is prominent. In some cases, swollen lacrimal glands can be palpated above the temporal lobe. In more cases, orbital CT scan showed lacrimal gland enlargement and lacrimal gland involvement in patients with thyroid-associated ophthalmopathy. The reason is still unknown. Histopathological examination showed mild monocyte infiltration and interstitial edema without extensive fibrosis. Khalid et al. measured the tears of 50 patients with thyroid-associated ophthalmopathy by HPLC and compared them with healthy people. The results showed that IgA level in tears of about 1/6 patients (8/50 patients) increased, but no abnormality was found in the control group. Globulin in 10 patients increased, suggesting that the protein composition of lacrimal gland changed.
(4) Orbital soft tissue swelling: Orbital contents are mainly composed of orbital fat and extraocular muscles. In patients with thyroid-associated ophthalmopathy in the acute stage, the orbital fat space is widened due to edema and congestion, and the extraocular muscles are enlarged due to edema and congestion. In the acute stage, inflammatory cells, especially lymphocytes, infiltrated and dilated blood vessels, which aggravated the swelling of orbital tissues, increased orbital contents, increased orbital pressure, blocked the return of ophthalmic veins, and more fluid gathered in soft tissues, making the swelling of orbital soft tissues more serious. Patients with ocular soft tissue involvement often have related symptoms, such as eye discomfort, dry eye, eye swelling and pain, foreign body sensation, photophobia, tears, diplopia, and decreased vision.
3. Exophthalmos [2] In addition to the special eyelid signs with diagnostic significance, exophthalmos is also a common sign. Simple exophthalmos has no diagnostic significance, but simple exophthalmos is rare in thyroid-associated ophthalmopathy, usually accompanied by some special eye changes. If it is only exophthalmos, other orbital diseases, especially orbital tumors, should be considered. The cause of exophthalmos is hypertrophy of extraocular muscles. Orbital fat increases, and the increased orbital contents move forward in the bony orbit, pushing the eyeball forward. Exophthalmos is the most common sign in patients with thyroid-associated ophthalmopathy, which can be divided into mild, moderate and severe. The exophthalmos of patients with thyroid-associated ophthalmopathy are relatively symmetrical, and the difference between the exophthalmos of both eyes is less than 5mm in 58% cases and less than 7mm in 89% cases. In short, the difference of exophthalmos between eyes is less than 10.
4. Subluxation of eyeball. Progressive thyroid-related orbital diseases can cause ocular subluxation, but it is rare, because the fat volume in the orbit increases rapidly, which leads to the eyeball moving forward, the equator of the eyeball reaching the orbital margin and the eyelid retracting. All patients with ocular subluxation showed an increase in orbital fat content, but the extraocular muscles did not increase significantly and there was no history of diplopia. Nunery reported that there are two subtypes of thyroid-associated ophthalmopathy: Type I, with normal eye movement or slight restriction after extreme turning, with different degrees of symmetrical exophthalmos and no orbital inflammation, is more common in young women, with an average age of 36 years, mostly women, and the ratio of male to female is 8∶ 1. Orbital CT scan showed that the orbital fat content (volume) increased with or without extraocular muscle enlargement, and type ⅱ was restrictive myopathy. The average age of exophthalmos is 52 years old, and the ratio of male to female is 2 ∶ L. CT scan shows that the extraocular muscles are asymmetrical, and most patients with incomplete dislocation of eyeball belong to type I.
5. Extraocular muscle involvement Thyroid-related ophthalmopathy often has restrictive extraocular muscle disease, also known as thyroid extraocular myopathy, which is characterized by enlarged extraocular muscle abdomen and normal muscle attachment. It is difficult to determine the clinical symptoms of patients with mild involvement. Ultrasound, CT or MRI examination can show that severe thyroid extraocular myopathy not only affects the patient's appearance, but also affects diplopia. It causes headaches and swollen eyes, and it is extremely difficult to live, study and work. The secondary effect is the decline of binocular collection function, which will not last long. After a long time, the patient felt eye swelling and pain, dizziness, similar to the clinical manifestations of glaucoma. The lesions of extraocular muscles are usually bilateral and muscular. The vertical muscle is more common than the horizontal muscle, and the lower rectus muscle is the most common, accounting for 60%, followed by the inner rectus muscle 50%, the upper rectus muscle 40% and the outer rectus muscle 29%. CT scan (horizontal and coronal) showed that abdominal muscles were spindle-shaped, with clear boundaries and no enlargement of tendons. The clinical manifestation of thyroid-associated ophthalmopathy can be diplopia, and the limitation of eye movement depends on the patient. However, 93% patients were confirmed to have extraocular muscle hypertrophy by orbital CT scanning. Orbital CT scan of thyroid-associated ophthalmopathy can not only be horizontal scan, otherwise unilateral inferior rectus hypertrophy will be mistaken for orbital tumor, and the correct diagnosis can be made only after coronal scan.
6. Corneal involvement is a common complication of thyroid-associated ophthalmopathy. There are the following types, with different degrees of severity. The most serious is the secondary infection of corneal ulcer. (1) Superficial punctate keratitis (SPK): corneal epithelium scattered or diffuse punctate shedding, located in the center of the cornea or other parts, stained with fluorescein or rose red to be punctate green or red, accounting for 8.3% of thyroid-associated ophthalmopathy. (2) Supra-limbal Conjunctivitis (SLK): It mostly occurs in young women and can be unilateral or bilateral. SLK accounts for 0.9% of thyroid-associated ophthalmopathy. Some patients can have these two symptoms at the same time, and some patients have been suffering from hyperthyroidism for many years before SLK appears. Clinical manifestations may include photophobia, foreign body sensation, recurrent attacks and diffuse congestion of upper eyelid conjunctiva. The upper part of bulbar conjunctiva is congested, 10 ~ 2 points, which can be light or heavy. The upper edge of cornea is gray and infiltrated, and thickening often forms a "groove" with the connected cornea. The punctate epithelium can be detached from the upper cornea, and the fluorescein staining is green. In addition, it may be accompanied by filamentous keratitis. If the upper eyelid does not turn over, it is often mistaken for chronic conjunctivitis and superficial scleritis. (3) Exposure keratitis or ulcer: Its clinical manifestations are dry exposure of cornea, epithelial shedding, serious secondary infection, gray cornea, inflammatory infiltration, necrosis and ulcer, which may be accompanied by hyphema or suppurative endophthalmitis. This is the most serious corneal complication of thyroid-associated ophthalmopathy. If the eyes are blind and painful, they will eventually need to be removed. The causes of exposure keratitis are: ② Eyelid swelling, decreased orbicularis oculi muscle function and difficulty in closure; ③ The bulbar conjunctiva is severely congested and edematous, protruding from the palpebral fissure, and the eyelid closure is blocked; ④ Extraocular muscles were involved, and Bell phenomenon to protect cornea disappeared.