posterior cataract
Introduction
Introduction to posterior cataract After-cataract refers to a special state in which the cataract is removed after surgery, or after the traumatic cataract cortex is partially absorbed, and the lens cortex or fibrous mechanical membrane is formed in the pupil area. This complication is particularly prevalent and severe in early intraocular lens implantation procedures where the importance of lens epithelial cells and cortical clearance has not been known. basic knowledge The proportion of sickness: 0.16% Susceptible people: no specific population Mode of infection: non-infectious Complications: glaucoma
Cause
Cause of posterior cataract
Cataract surgery is not complete (35%):
If the cataract surgery is not complete, there will be residual lens after surgery. The proliferation, migration and fibrosis of residual lens epithelial cells are the main causes of post-developmental dysfunction. The cells that may proliferate are cells with mitotic activity in cuboid anterior epithelial cells and equatorial arch. The lens epithelial cells remaining in the lens capsule proliferate on the inner surface of the capsular bag and extend from the edge of the anterior lens capsule to the anterior surface of the intraocular lens (IOL).
Other (15%):
The pathological changes involved in posterior dysfunction are: macrophage-mediated foreign body reaction, multi-macrophage fusion to form foreign giant cells; lens epithelial cells involved in wound healing; lens epithelial cells are transformed into lenticular fibers at the equator Sommerring ring; posterior capsule lens epithelium extends to form fibroblasts or form Elschnig beads.
Prevention
Posterior cataract prevention
The principle of PCO prevention can be divided into two aspects: intraoperative efforts to remove residual lens epithelial cells and cortex; if some cells remain, create a physiological barrier at the edge of the intraocular lens optic zone to prevent cells growing from the equator Reach the boresight.
Complication
Complications of posterior cataract Complications glaucoma
Soemmering ring into the anterior chamber can stimulate acute inflammation and glaucoma. Glaucoma: An eye disease that refers to intraocular pressure or intermittent or continuous elevation. Increased intraocular pressure can have a variety of different symptoms depending on the cause. Sustained high intraocular pressure can cause damage to various parts of the eye tissue and visual function, resulting in decreased vision and reduced visual field. If left untreated, the vision can be lost or even blind. Therefore, glaucoma is one of the main diseases of blindness.
Symptom
Symptoms of posterior cataract Common symptoms Visual field of vision changes visual impairment Pupils turn white to see things have a tendency to ghost bleeding
1. Correcting poor vision;
2. The posterior capsule is turbid and has a thickness of white machined tissue, which may have post-iris adhesion;
3. The degree of visual impairment depends on the thickness of the organic film.
Examine
Examination of posterior cataract
Pathological examination:
Secondary to cataract after cystectomy, linear removal or extracapsular enucleation, residual lens hydronephrosis, formation of large and round bladder-like cells, and liquid, Markov and transparent in between Like a mass, there may also be deposits of cholesterol or calcium. Epithelial cells in the equatorial region often proliferate significantly, and nuclear fission occurs. It can be considered that the regeneration of the sacs, the proliferation of the sac epithelium, and even the growth of the anterior capsular rupture, the formation of large vacuoles in the proliferating epithelial cells, called the lens epithelial Elschnig beads. The formation of cystic epithelium is sometimes seen. When blood enters the capsule, spindle cells and fibers can proliferate in a fibrous tissue shape. When the iris pigment particles are decomposed from the pigment epithelium, the lens capsule can be coated with a pigment. Pigment epithelial cells with phenomenological proliferation are intermingled in lens cells and lens material. When there is inflammation, polymorphonuclear leukocytes can enter the posterior cataract. If the ciliary membrane is formed, it is often connected with the posterior cataract and can enter it.
Special inspection:
There are doubts or special requirements for the surgical results, and patients with other eye diseases are suspected to have relevant eye special examinations.
1. Corneal endothelial cell examination: The ratio of cell density (CD) and Hexagocyte was observed. When the corneal endothelium is less than 1000/mm2, the cataract surgery should be carefully considered to avoid postoperative corneal decompensation and affect the surgical outcome and postoperative recovery.
2. Retinal visual inspection: Projecting a specific image or visual target onto the retina, regardless of whether the refractive interstitial is turbid, directly examining the visual acuity of the retina to understand the optimal visual acuity that can be achieved after the patient's surgery, and preoperative evaluation of the macular function. An important method of inspection.
3. Visual field examination: For patients with light opacity of the lens and a certain visual acuity, visual examination may reveal other diseases with cataract. For example, the central dark spot should be alert to the presence of macular degeneration, the expansion of the physiological blind spot and the characteristic defect of the visual field should be alert to the presence of glaucoma and other fundus lesions. Since the cataract also causes a change in the visual field, it is necessary to identify the opaque portion of the lens observed by the slit lamp.
4. Electroretinogram (ERG) examination: There are currently three kinds of ERG, such as flash, graphics and multifocal, which can record the cone function, rod function and mixing function of the retina. The flash ERG reflects the function of the entire retina. The graphic ERG mainly reflects the function of the macula. Multifocal ERG can simultaneously record ERG at more than 100 retinal sites in the central 30° field of view, which is conducive to the diagnosis and judgment of postoperative retinal function. Clinically, the flash ERG is often used. If the preoperative ERG is normal or slightly reduced, it is estimated that the postoperative visual acuity recovery is good. If the preoperative ERG is significantly reduced or not recorded, it is estimated that the postoperative visual recovery is not ideal.
5. Visual Evoked Potential Examination (VEP): VEP includes flash VEP and graphic VEP for recording neural pathway function from the retina to the visual cortex. When the macular and optic nerves appear lesions, they can show a decrease in amplitude and an increase in latency. When the patient's preoperative visual acuity is less than 0.1, a flash VEP examination is generally used. When the patient has good visual acuity, a graphical VEP examination can be used. Therefore, when the lens is obviously turbid, the VEP examination has a more accurate predictability of the recovery of postoperative visual function.
Diagnosis
Diagnosis and diagnosis of posterior cataract
Diagnostic criteria:
After extracapsular cataract extraction or ocular trauma, residual cortical or epithelial cells on the posterior capsule of the lens proliferate and turbid.
1. Have a history of surgery or trauma.
2. It manifests as simple posterior cataract, Soemmering ring, Elschnig beads, and mechanical film.
3. Sometimes there is adhesion after the iris.
4. Vision has varying degrees of damage.
5. YAG laser treatment or surgical treatment can be performed according to the situation.
Differential diagnosis:
Posterior cataract is formed after cataract surgery and has very significant clinical features.
