Terrien limbic degeneration

Introduction to Terrien corneal marginal degeneration Terrien Marginal Degeneration (TMD) is a special type of degeneration of the limbus of the cornea. It is rare, mainly characterized by chronic, bilateral corneal parenchyma with shallow neovascularization at the edge of the bilateral cornea. The shape becomes thinner, and eventually the cornea bulges forward, and the perforation and iris are released, causing serious damage to the eyeball. basic knowledge The proportion of illness: 0.0035% Susceptible people: no specific population Mode of infection: non-infectious Complications: conjunctival hyperemia

Terrien corneal marginal degeneration etiology

(1) Causes of the disease

The exact cause is unclear and is thought to be related to endocrine disorders, ocular manifestations of collagen disorders, neurotrophic disorders or limbal capillary dystrophy and other factors, which have recently been considered an autoimmune disease.

(two) pathogenesis

The pathogenesis of Terrien's corneal limb degeneration has not been known so far, and the following speculations exist.

1. Immune disease: TMD occurs in the limbus, the limbus is the active part of the immune response; histologically found that the corneal collagen fibers in the lesion are swallowed by tissue cells containing high lysosomal enzyme activity; TMD can be associated with certain Collagen diseases such as rheumatic diseases, spring conjunctivitis, etc.; corneal pathological tissue sections found macrophages, lymphocytes and a small number of plasma cells, Lopez immunohistochemical examination of the cornea of a patient with TMD, showing 25% cell expression HLA-DR, HLA-DQ, TH:TS=1:1, but Berkowitz found that the immune complex in the serum of TMD patients, circulating antibodies did not differ from the normal control, suggesting that at least type III allergy does not participate in the onset.

2. Nutritional disorders: TMD is bilateral, progressive disease, clinical manifestations and laboratory data show that TMD lacks inflammatory manifestations; pathological examination revealed lipid deposition in the lesion area, cholesterol crystallization, and some patients with xanthomas, suggesting For lipid degeneration; TMD corneal collagen fibers undergo cellulose-like degeneration, Pouliquen Y found a case of TMD with keratoconus, which is a fibrotic disease.

3. Inflammatory diseases: Some patients are accompanied by irritation symptoms, corneal pathological sections find a small number of inflammatory cells such as neutrophils, lymphocytes, macrophages, Reboul, Iwamoto believes that the disease is the result of inflammation, and TMD is based Electron microscopy was divided into 2 types: inflammatory and non-inflammatory. The former was characterized by neovascularization around the corneal lesions and conjunctival hyperemia. Electron microscopy showed thrombosis in the neovascularization of the lesion, surrounded by lymphocytes and neutrophil infiltration. Fibrinous necrosis occurs, but Folk believes that the inflammatory response may be secondary to the immune response caused by corneal necrosis, which is the result of TMD and not the cause.

4. Abnormalities in the composition of tears: The tears in the tears of patients with TMD in Hayasok patients compared with normal people found that the activity of lysosomal enzymes such as N-acetyl--D-glucosaminase in TMD patients was higher than that of the normal control group, but It was not determined whether this enzyme originated from abnormal secretion of the lacrimal gland or from cells in the corneal tissue.

5. Others: Some TMD, keratoconus and other corneal stroma-dissolving diseases are combined with spring catarrhal conjunctivitis. It is speculated that the marginal eosinophils increase and release inflammatory mediators such as metalloproteinase, leading to progressive thinning of the cornea.

Terrien corneal marginal degeneration prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Terrien corneal limb degeneration complications Conjunctival congestion

The eyeballs are shrinking.

Terrien corneal marginal degeneration symptoms common symptoms visual impairment photophobia conjunctival hyperemia cyst corneal ulcer large corneal tears

About 75% of the patients are male, most of them are 20 to 40 years old, usually both eyes are affected, but the progress of the disease is often inconsistent with the severity of the disease, the course is longer and the progress is slow, sometimes up to 20 years or more, the elderly case The progression of corneal thinning is slower, and the lesions begin more than above the cornea. The early shape resembles the old ring, and there is a small punctate stromal opacity around the sulcus. The opacity is parallel to the limbus and there is a gap between them. The interval extends into the turbid area, and there is a yellow-white strip of lipid deposits at the end of the vasospasm. The lesion is slowly progressively thinned and has an arc-shaped groove-like depression. The lesion can expand toward the center and both sides, and the cornea of the groove The central side edge is steep, and the peripheral side is sloped. The bottom cornea of the groove is very thin. It expands forward under the action of intraocular pressure. The corneal epithelium usually remains intact. It is often overlooked due to lack of self-conscious symptoms, and gradually develops with the disease. Mild irritation may occur, such as photophobia, tearing and foreign body sensation. In the late stage, the corneal lesions bulge forward, producing obvious corneal astigmatism and varying degrees of visual loss. Due to minor trauma or spontaneously thinnest corneal perforation.

As the disease progressed, Francois divided it into four phases:

1. Infiltration period: A 2 to 3 mm wide gray-white turbid zone parallel to the limbus appears in the peripheral part of the upper cornea, accompanied by neovascularization, and the surrounding conjunctiva is slightly congested and dilated.

2. Degeneration period: the lesion gradually waved and the stromal layer, the tissue became denatured and thinned, forming a curved vascular sulcus-like depression zone, the shallow tissue was gradually melted and absorbed, and there was lipid deposition in the groove.

3. Expansion period: the cornea of the lesion area continues to be thinner, and there are single or multiple porphyritic bulging areas of 1.5 to 3.0 mm or more, which have a small cyst-like appearance, and there may be significant retrograde astigmatism at this time.

4. Keratoconus: Under the action of intraocular pressure, the tissue tension of the lesion area is significantly decreased, so that the corneal bulging is conical, and the lesion can spread to the central or side center, showing a keratoconus-like appearance. At this time, when coughing or minor trauma, sometimes Even spontaneously occurs in the cerebral rupture of the cornea, causing the outflow of the aqueous humor, the iris to escape, followed by the adhesion of the cornea to the plaque. In severe cases, the iris occurs after the corneal rupture, and the lens and vitreous body are prolapsed. If not treated in time, the eyeball can be destroyed.

Terrien corneal marginal degeneration

Many scholars have speculated that TMD is an autoimmune disease, but there is still no exact immunological basis. Lopez and other corneal lesions of TMD and ectopic corneal ulcer are immunohistochemically examined to express HLA-DQ and HLA-DR. The antigenic cells accounted for 25% of the TMD samples, 75% to 100% in the necrotic corneal ulcer samples, 1:1 for the CD4+:CD8+ cells, 2.4:1 for the necrotic corneal ulcers, and CD22+ cells. TMD accounts for only 5%, while necrotic corneal ulcers account for 25% to 50%, but because the sample size is too small, the above results can only explain the clinically more significant inflammatory response of necrotic corneal ulcers than TMD.

Hematological tests for collagen vascular diseases such as rheumatoid factor, antinuclear antibodies, and anti-neutrophil cytoplasmic antibodies can be used for the identification of other similar corneal diseases.

Diagnosis and differentiation of Terrien corneal limbal degeneration

According to the clinical manifestations, the progressive visual acuity was not obvious when the irritation symptoms were obvious. The eye examination showed that the corneal edge was thin and the lesions circled, and the corneal epithelium was intact in the lesion area, accompanied by superficial neovascularization and lipid deposition. With inflammatory response; combined with corneal topography shows that corneal diopter is the highest in the limbal lesions, and corneal irregular astigmatism can be diagnosed.

Peripheral corneal degeneration around Terriens is a peripheral corneal thinning disease, usually located in the upper peripheral cornea, the incidence of both eyes, generally without eye pain and inflammation, the corneal epithelium is intact, the thinned area slowly progresses to the center of the cornea, but rarely involves the central cornea There is no chisel-like edge, and lipid deposition is usually seen in the leading edge of the thinned area of the cornea, often accompanied by corneal neovascularization, which can be distinguished from encroaching corneal ulcer.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.