Lens siderosis

Introduction Iron is the most common intraocular foreign body. Foreign matter in the crystal can form a localized cataract. If the iron foreign body is small, it can exist in the crystal for many years without obvious reaction. Iron can be oxidized in the eye and gradually in the eye. Diffusion, the formation of eye rust, including the cornea, iris, lens, retinal rust, eventually leading to blindness, the rust of the eye is related to the size and position of the foreign body in the eye, the larger and the iron in the back of the eye is easy to the eye After the section moves. There are small brownish yellow spots under the anterior capsule of the initial crystal, and there are brown rust spots under the anterior capsule in the late stage. The initial stage must be enlarged after the pupil is enlarged. The late stage crystal fiber degeneration gradually develops into an all white cataract, and finally the crystal is curled, or Due to the degeneration of the suspensory ligament, the cataract occurs because of the cataract caused by the absorption of iron by the epithelial cells, and the growth of new fibers is blocked. At this time, even if the cataract is removed, the visual acuity cannot be recovered quickly. Lens rust is a clinical symptom of traumatic cataract. Direct or indirect mechanical damage acts on the lens, causing a change in turbidity called a traumatic cataract. Patients are more common in children, young men and soldiers. There are three common types of cataracts caused by blunt contusions, blast injuries, and eye penetrating injuries. Due to the different factors of injury and local performance, the disease has a variety of names. Most cases can be described as a history of traumatic trauma, but traumatic cataracts that deny the history of trauma must not be ignored, especially in infants and young children.

Cause

(1) Causes of the disease

Common causes include eye penetrating injuries, eyeball bruises, and electric shocks.

The cataract of contusion: caused by boxing or ball or other objects hitting the eyeball. The conduction of external water causes the external force to act on the lens lacking elasticity, and also rebounds on the surface of the vitreous. Therefore, the blunt contusion causes diversity of lens opacity, namely Vossius. Annular opacity, rose turbidity, nuclear cataract, point cataract and total cataract. In blunt cataracts, trauma causes damage to the lens epithelial function, leading to edema and degeneration of the superficial cortical lens fibers, resulting in a localized and permanent thin-layer vacuole. Over time, new normal lens cells form, and the injured epithelial layer is compressed and embedded, entering the deep cortex and eventually forming turbidity.

Through-injury cataract: the penetrating injury of the eye also causes the lens capsule to rupture, and the aqueous humor enters the lens, causing fiber edema, degeneration and turbidity. If the perforation is extremely small, it can be closed by itself, so that the lens has limited local turbidity and no longer develops. However, after the lens capsule is damaged, most human cortex rapidly appears turbid, and the large perforation can also cause secondary glaucoma due to excessive expansion of the lens cortex.

(two) pathogenesis

In the basic research of traumatic cataract, it was found that various emergency factors, such as oxidizing substances, ultraviolet rays and toxic substances, can initiate apoptosis of lens epithelial cells. Therefore, it is considered that lens epithelial cell apoptosis is non-congenital cataract in humans and animals. A universal cytological basis. A rat model of blunt traumatic cataract has been established in China. It has been found that the ultrastructure of lens epithelial cells in SD rats has undergone significant changes: nuclear membrane damage, invagination, chromatin condensation; mitochondrial structure destruction, vacuolization changes, The number is reduced; the endoplasmic reticulum expands and conforms to the morphological manifestations of apoptosis. Thus, the occurrence of blunt cataract may be related to apoptosis of lens epithelial cells.

Studies have found that the accumulation of extracellular matrix is initiated during the healing of lens trauma after penetrating wounds. The main components include chondroitin sulfate, heparin sulfate and collagen. The accumulation of extracellular matrix under the capsule not only causes wrinkles of the lens capsule, but also strengthens the adhesion, proliferation and migration of lens epithelial cells, eventually leading to opacity of the lens. Matrix metalloproteinases (MMPs) and their transplanted TIMPs play an important role in the aggregation and degradation of extracellular matrix. MMPs promote the accumulation of extracellular matrix, while TIMPs promote degradation. In the study of the rabbit cataract model, the activity of TIMP-1, 2 in the injured eye increased significantly on the first day after injury, and then gradually decreased, and the change of MMPs-2 activity corresponds to this, that is, in the injury After the first day, it was suppressed and gradually recovered. Therefore, it is speculated that the transient increase of TIMP-1 and 2 in rabbit eyes changes the balance of MMPs/TIMPs, which may antagonize the degradation of extracellular matrix by MMPs and inhibit the development of intraocular inflammation after injury. The process of extracellular matrix remodeling and cell proliferation and repair after tissue injury is enhanced to promote wound healing, but excessive aggregation of extracellular matrix and excessive cell proliferation may lead to opacity of the lens.

an examination

Related inspection

Examination of the lens and CT examination of the temporal region

1. History of trauma: There are signs of trauma in the eye of this disease.

2. Vision loss: the patient has blurred vision, single eye double vision or multiple vision, or vision quickly drops to light perception.

3. Lens opacity: turbidity is localized or diffuse. Turbidity mainly occurs in the cortex, but also in the nucleus. It is rare in the capsule, because the capsule is thin and elastic. After the injury, the capsule is ruptured into the outer or inner pleats. A thickening of the capsule or scarring of the epithelial proliferation results in "capsule opacity".

Differential diagnosis

Differential diagnosis of lens iron deposition:

1. Radiation cataract:

(1) The patient has a history of radiation.

(2) Chronic X-ray and other radiation damage to the lens, turbidity often starts from the posterior pole, and there may be three types of posterior subcapsular vesicles in the posterior capsule, haze turbidity in the posterior capsule, and flaky opacity in the posterior capsule. Occurs, but mostly mixed.

(3) Cavitation occurs in the posterior capsular cortex. The vacuoles are small and round, or remain unchanged for a long time, or become a small white spot through cheese, which cannot be absorbed by themselves and gradually expands toward the front and the equator.

(4) For a long time, the cortical opacity of the posterior capsule is mostly foggy and dotted, and the whole is thin and round. The initial stage is limited to the radius of 2mm near the posterior pole, and is close to the posterior capsule and far from the posterior nucleus. .

2. High myopic posterior capsule cortical opacity: often brown, and the cortex is completely turbid after self-nuclear.

3. Diabetic-induced lens lesions: Although they can be located in the posterior capsule of the posterior capsule, small vacuoles are large, not round, and the number is large, and the integrated group can be enlarged or reduced. The vesicles caused by radiation are mainly located under the posterior posterior capsule and do not reach the posterior pole. Its characteristics are small and round, and the shape of small bubbles is stable and long-term unchanged.

4. Body copper deposition: If the copper content is more than 85%, it has obvious damage to the eye tissue. Pure copper can cause suppurative changes in the eye. Cataract caused by copper foreign bodies in the crystal can cause iridocyclitis in the anterior chamber and damage to the optic nerve, retina and choroid in the posterior pole. Copper ions are deposited in the tissues of the eye as rust, and the elastic layer deposited in the cornea may have a blue-green ring (Kayser-Fleisher ring). The iris is light green, the body has many color bodies, and the retina has green pigment. The crystal has a sunflower-like cataract due to copper deposition, and there is a rainbow-like change in the pupil area, and the surface of the crystal is velvety. The posterior capsule of the crystal is a green shark grass. The effect of sunflower-like cataract on vision is not very serious. If copper foreign matter is found in the crystal, it must be removed as soon as possible. Because even if there is tissue wrapped around the foreign body, it will cause necrosis of the eye tissue, resulting in blindness. This is different from the iron foreign matter in the crystal.

Crystalline copperosis is a clinical symptom of traumatic cataract. Direct or indirect mechanical damage acts on the lens, causing a change in turbidity called a traumatic cataract. Patients are more common in children, young men and soldiers. There are three common types of cataracts caused by blunt contusions, blast injuries, and eye penetrating injuries. Due to the different factors of injury and local performance, the disease has a variety of names. Most cases can be described as a history of traumatic trauma, but traumatic cataracts that deny the history of trauma must not be ignored, especially in infants and young children.

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.