Symptom >> Otorhinolaryngology >> Ophthalmology

Corneal lens adhesions

Introduction
Cause
Examine
Diagnosis

Introduction

Introduction Peter's abnormal performance is congenital leukoplakia in the central part of the cornea, and there are defects in the posterior stromal layer and posterior elastic layer. In the area where the cornea is turbid, there is adhesion from the center to the periphery of the iris. 8% of patients were afflicted with both eyes. Corneal edema is optional, white spots are thick and large can not see the anterior chamber. Due to corneal edema, the early cornea has a ground-glass appearance and a bit of epithelial staining. For example, aggravation of corneal edema indicates that the lesion is progressing, and glaucoma exacerbates this condition. However, if the intraocular pressure is normal, the edema will gradually disappear, leaving a corneal scar with a clear boundary and a normal lustrous epithelium. Although the hardening of the limbus is common, the peripheral cornea is often transparent, and the affected cornea has few blood vessels.

Cause

Cause

(1) Causes of the disease

The cause of Peter's abnormality is not fully understood, but different changes were found from histopathology and electron microscopy. It is not considered to be a single cause. It was originally thought to be due to intrauterine infection (Von Hipple intracorneal ulcer). This theory is believed to be obtained by amniotic fluid or placenta. Intrauterine keratitis, causing perforation of the cornea, causing the iris-lens to move forward, causing posterior corneal defects, corneal leukoplakia and corneal lens and iris corneal adhesions. These changes can also be caused by deep corneal abscess, pus drainage in the frontal room, no Corneal perforation, foreign reports of 5 of the 21 patients with congenital central corneal thick opacity and central anterior adhesions, in the first 3 months of pregnancy have been viral, especially rubella infection, also reported a case of Peter abnormalities The monocular patient has congenital cytomegalovirus infection, the contralateral eye is normal eye, and a batch of specimens of Peter's abnormal patient are examined by electron microscopy. The cells of the posterior corneal stroma are chronic inflammatory cells, which are destroyed by light microscopy. Abnormal fibroblasts and histiocytes can be seen in the stroma. In patients with abnormal lens, it may be Bubble in the lens and the surface due to incomplete ectoderm.

(two) pathogenesis

There is still debate about the pathogenesis of Peter's abnormality. Tripethi believes that the central corneal defect is due to the ingrowth of the first and second mesenchymal cells at the edge of the cup at 10 to 14 mm of the embryo; the posterior corneal elastic layer Abnormalities and loss of endothelial cells are due to defects in primary mesenchymal cells, which may be further affected by delayed or incomplete separation of lens bubbles; lens opacity and formation of corneal lens cords may be associated with ectoderm In relation to the defects, in summary, the different manifestations of Peter's abnormalities are related to the developmental defects of the corneal endothelium, the corneal stroma and the iris matrix during the three stages of the leaf tissue, which may or may not be accompanied by abnormalities of the lens vacuoles.

Kupfer uses some obstacles in the migration process of neural crest cells or some defects induced by terminal to explain the changes of anterior ocular mesoderm dysplasia and secondary glaucoma including Peter's abnormality, corneal stroma. Migration or terminal induction disorders can lead to a series of corneal opacity and dysplasia. Endothelial cell defects can cause defects in the posterior elastic layer and abnormal corneal water content. This abnormal endothelial cell may have extra "stickiness". , resulting in corneal iris adhesion, partial or total disappearance of the iris matrix can have secondary effects on the iris pigment epithelium and pigment-free epithelium underneath, resulting in a series of pupil abnormalities and pigment epithelial defects, if the defects of the iris matrix develop To a certain extent, enough to affect adjacent tissues, such as the lens and its suspensory ligament, can produce lens ectopic and anterior polar cataract, trabecular endothelium migration or terminal induction process obstacles, can make normal aqueous water outflow resistance Mutation occurs and causes an increase in intraocular pressure. This increase in intraocular pressure does not necessarily coincide with the number of iris cords attached to the cornea and trabeculae. Proportionally, Kupfer et al reported that a 2-year-old child with glaucoma, the ultrastructure of the trabeculectomy specimen showed typical aging changes in the trabecular meshwork, and some scholars believe that the drainage of the aqueous humor may be due to the fine angle of the iris cornea. The change is caused.

Others found that histopathological changes in Peter's anomalies and complete defects in the retinal pigment epithelial and posterior choroid, found complete peripheral pre-iris adhesion with atrophy of the iris matrix, and no trabecular meshwork and Schlemm tube structure. In other cases, the neural crest cells with iris corneal angle were incompletely differentiated, with more typical Axenfeld abnormalities and Rieger syndrome.

Examine

an examination

Related inspection

Corneal examination and CT examination of the temporal region

According to the above-mentioned characteristic clinical manifestations such as the central part of the cornea, the iris and the lens, it is not difficult to make a diagnosis. If there is an increase in intraocular pressure, the diagnosis of secondary glaucoma can be diagnosed. The measurement of intraocular pressure is preferably measured with a Tono-pen tonometer to reduce or be unaffected by corneal leukoplakia.

Peter's abnormal performance is congenital leukoplakia in the central part of the cornea, and there are defects in the posterior stromal layer and posterior elastic layer. In the area where the cornea is turbid, there is adhesion from the center to the periphery of the iris. 8% of patients were afflicted with both eyes. Corneal edema is optional, white spots are thick and large can not see the anterior chamber. Due to corneal edema, the early cornea has a ground-glass appearance and a bit of epithelial staining. For example, aggravation of corneal edema indicates that the lesion is progressing, and glaucoma exacerbates this condition. However, if the intraocular pressure is normal, the edema will gradually disappear, leaving a corneal scar with a clear boundary and a normal lustrous epithelium. Although the hardening of the limbus is common, the peripheral cornea is often transparent, and the affected cornea has few blood vessels. Iris and corneal adhesions are often located in the ciliary area of the temporal iris, and there are corneal leukoplakia at the corresponding sites, but the corneas in other directions are more transparent. Adhesion can be local or extended to the 360° iris ciliary area.

Peter's abnormalities are often accompanied by generalized abnormalities such as short stature, mental retardation, lip and jaw and cleft palate and ear abnormalities. There are also reports of cerebral palsy, small red sputum, toothless, less teeth, fingers (toe), flexion fingers, short head deformity, semi-lateral dysplasia, Wilsm tumor, craniofacial osteogenesis imperfecta, hydrocephalus, no brain , pulmonary hypoplasia, Dandy-Walker syndrome, cardiac and genitourinary abnormalities, Lowe syndrome. Someone has classified Peter's exception into 3 types:

1 without corneal lens adhesion or cataract;

2 with corneal lens adhesion or cataract;

3 accompanied by Rieger syndrome.

Diagnosis

Differential diagnosis

For newborns and babies, it is mainly to identify central corneal leukoplakia and other causes of corneal opacity. These other causes are congenital glaucoma, mucopolysaccharidosis, birth trauma, congenital hereditary corneal dystrophy, and corneal opacity. The corneal opacity caused by birth injury, the tear of the posterior elastic layer is vertical corrugated; the difference between Peter's abnormality and congenital glaucoma is that the corneal diameter is not enlarged, and the corneal opacity and the transparent area have obvious boundary lines. When the intraocular pressure drops, the corneal opacity will not become transparent, and there is a shallow anterior chamber; the corneal opacity of the mucopolysaccharidosis is diffuse, with a small punctate stromal layer turbid, and the opacity in the posterior part is denser than the anterior part, the epithelium is None of the endothelium was involved; congenital hereditary corneal endothelial cell dystrophy was not associated with glaucoma, corneal opacity was uniform, anterior chamber formation was good, and no abnormal iris was observed; corneal ulcer perforation, iris was embedded in corneal scar, and Peter was abnormal The iris is attached to the vicinity of the opaque cornea. If the corneal opacity progresses, the anterior chamber condition is more difficult to understand, and it is difficult to diagnose correctly.