True small eyeballs
Introduction
True Eyes Introduction Nanophthalmos is the development of the fetus. The eyeball stops developing after the embryonic fissure is closed. The volume of the eyeball is smaller than normal and there are no other congenital malformations. basic knowledge The proportion of illness: 0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: nystagmus
Cause
True small eyeball cause
(1) Causes of the disease
Associated with abnormalities in embryonic development.
(two) pathogenesis
After the development of the original optic vesicle, the embryo may become a small eyeball due to various reasons, and if the process of occlusion of the original optic blister is affected, the congenital sac can be produced. Small eyeballs.
According to the influence of embryonic development, the small eyeballs can be divided into three types: the eyeball development is stagnant after the embryonic fissure is closed, and there are no other abnormalities at all. Only the eyeball volume is smaller than normal, which is called simple or true small eyeball. Embryo rupture incomplete, combined with a variety of congenital malformations, known as defective small eyeball; secondary to other congenital malformations and unrelated to embryonic stenosis, known as concomitant small eyeball, the pathophysiological mechanism of small eyeballs showed The proportion of various tissues in the eyeball is not commensurate, that is, the so-called lens/eye volume ratio is high, so the anterior segment of the eye is very crowded. Singh et al. used ultrasound to measure 22 true small eyeballs, and the lens was occupied by the lens. The average volume of the eyeball is 12.16%, while the normal eye is only about 4%. In addition, the thickness of the lens is larger than that of the normal spherical lens. The relatively large and forward-moving lens can increase the contact with the iris and cause pupillary block, resulting in the angle of the corner. Narrow or closed, causing angle-closure glaucoma.
Prevention
True small eye 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.
Complication
True small eyeball complications Complications, nystagmus
Retinal cysts or abnormalities of the macula, strabismus and nystagmus.
Symptom
True small eyeball symptoms Common symptoms Retinal edema Small eye strabismus
True small eyeball refers to a rare type of congenital abnormality in which the eyeball is arrested and the eyeball is stagnant, and the eyeball volume is smaller than normal without other congenital malformations (Fig. 1). The clinical manifestations mainly have three characteristics: small eyeball and height. Hyperopia or with macular degeneration and glaucoma in the late stage, monocular incidence with ipsilateral dysplasia, and even ipsilateral body dysplasia, bilateral morbidity can show short body, forming part of the whole body gnome, its clinical manifestations are as follows:
1. Small eyeball
Usually the eye crack is small, the volume of the eyeball is about 2/3 of the normal eye, the sagittal diameter of the eyeball is 1618.5mm, the vertical diameter is 1417.1mm, the corneal diameter is also small, usually below 10mm, the anterior chamber Shallow, narrow angle of the anterior chamber, poor retinal dysplasia, fine and tortuous blood vessels, may be associated with retinal cysts or abnormalities of the macula, and the optic disc is uplifted, showing the appearance of pseudo-opic discitis.
2. Refractive error
The refractive state is usually high hyperopia, which can be as high as +11D to +21D, but there are also reports of high myopia, ametropia may be due to corneal or lens morphological variation, axial ametropia and progressive changes, most patients with vision Low and poorly corrected, which is associated with retinal dysplasia, and some patients are also accompanied by strabismus and nystagmus.
3. Glaucoma
True small eyeballs are more common with glaucoma, which is related to factors such as small anterior segment of the eye and relatively large lens in the lens or embryonic tissue in the iris cornea. These glaucoma are mostly found in middle-aged people, but there are reports of childhood morbidity. Its clinical features: 1 is characterized by chronic angle-closure glaucoma, no pain, progressive increase in intraocular pressure; 2 antispasmodic drug therapy is anti-invasive; 3 traditional anti-glaucoma surgery often fails, and postoperative eye is prone to occur Complications, such as severe choroidal leakage, vitreous hemorrhage and secondary retinal detachment, glaucoma should be treated with drugs first, but the use of miotic agents often poorly responded, such as when the intraocular pressure is uncontrollable or progressive optic disc damage is considered. Surgery, performing lens removal and filtration surgery is a more common procedure. Early use of laser angle angulation plus iridotomy is a safe and effective method.
Examine
True small eye exam
No special laboratory tests.
A super or B-ultrasound measures the length of the eyeball and clarifies the structure of the eye.
Diagnosis
True small eye diagnosis
Usually, the eye with an axial length of 19mm is diagnosed as a true small eyeball. The typical small eyeball has small eyeball, small cornea, shallow anterior chamber, narrow angle of the anterior chamber, thick sclera, normal lens size or spherical lens, and macular dysplasia. Such clinical features, due to eyeballs, cleft palate and small cornea, should pay attention to the impact of intraocular pressure measurement, it is best to use an applanation tonometer or Tono-pen tonometer.
