广西医科大学第一临床医学院眼科,1,Disease of the lens,EYE No.1,Anatomy and Physiology of the lens,Position: The lens connected with the ciliary body by the suspensory ligament that fixes it behind the iris, in front of the vitreous.,EYE No.2,2,广西医科大学第一临床医学院眼科,Anatomy: The lens is composed of lens capsule and lens fiber. The lens capsule is a layer of elastic homogeneous membrane. The lens fibers are the extension and elongation forwards and backwards of the epithelial cells at the equator.,3,广西医科大学第一临床医学院眼科,It is approximately 9mm in diameter and 4-5mm in the thickness. But we only use 2.5-4mm in the center (because the iris keeps out the rest lens and only can views the center portion through the pupil.),4,广西医科大学第一临床医学院眼科,Physiology of the lens The lens is s kind of transparent and non-blood vessel tissue. It is an important part of refractive media of the globe. The lens nourishment are offered by aqueous humor.,5,广西医科大学第一临床医学院眼科,The disorder of the lens commonly if loss of its transparency (cataract ) and abnormality of its position; both can induce severe visual disturbance.,6,广西医科大学第一临床医学院眼科,Cataract,Cataract is the first cause of blindness in China and other many developing country. There are one million of cataract sufferer who are in need of operation to restore their visions.,EYE No.4,7,广西医科大学第一临床医学院眼科,Classification,According to the age of occurring: Congenital cataract Infantile cataract Juvenile cataract Adult cataract Age-related cataract (senile),EYE No.5,8,广西医科大学第一临床医学院眼科,According to etiology: Traumatic cataract : blunt or penetrating injury Complicated cataract: uveitis Metabolic cataract: diabetes Drug-induced or toxic cataract Developing cataract After-cataract,9,广西医科大学第一临床医学院眼科,age-related cataract,It is the most common cataract, often seen in the olds with age more than 50 years old. The incidence of the disease is 100% when the patient exceed 80 years old.,EYE No.6,10,广西医科大学第一临床医学院眼科,Pathologic mechanism,The disease is related with several factor: Ultraviolet ray Genetic factor Systemic disease such as diabetes, hypertension. Lens nourishment and metabolic condition,11,广西医科大学第一临床医学院眼科,Clinical findings: Bilateral disease Fixed black spot before the eyes Visual decrease without pain Refractive change,EYE No.7,12,广西医科大学第一临床医学院眼科,classification According to the site where cataract begins to form:,cortical,Anterior capsule,Posterior capsule,subcapsular,Age-related cataract,EYE No.8,nuclear,13,广西医科大学第一临床医学院眼科,cortical cataract It is divided into 4 stages:,Incipient stage: To begin opacity appears at the periphery of anterior and posterior cortex The center lens is almost clear, the pupillary area isnt affected, commonly without influencing vision. To be diagnose after mydriasis under slit-lamp examination. To develop slowly,EYE No.9,14,广西医科大学第一临床医学院眼科,EYE No.10,Immature stage(intumescent stage) The opacity gradually becomes obvious The cortex absorbs water to become swollen Iris projection: the characteristic of this stage Vision has obviously decreased The fundus cant be observed in Some patient may induce acute attack of glaucoma due to shallow anterior chamber,15,广西医科大学第一临床医学院眼科,Iris projection: To examine with oblique illumination, the iris shadow on projected side falls on opaque cortex in deep layer, a crescent projection appears at the pupil of the side.( because there is transparent cortex between iris pupillary margin and lens cortex),16,广西医科大学第一临床医学院眼科,Mature stage The lens has become opaque at all in cream white color The iris projection disappeared The fundus cant be looked in Vision decreases to light perception or hand movement But the light seeking and color sensation are in normal.,17,广西医科大学第一临床医学院眼科,Hypermature stage When the mature stage continues for over long time,the water in the lens has been lost continuously, the volume of the lens diminishes, the capsule shrinks,the anterior chamber deepens with iridodonesis. Vision may increase suddenly,18,广西医科大学第一临床医学院眼科,Morgagnian cataract: the lens fibers are decomposed and dissolved in cream-white liquefaction, brown-yellow hard nucleus sinks down, the anterior chamber in upper part become deep.,19,广西医科大学第一临床医学院眼科,When the lens capsule ruptured Phaco-anaphylactic uveitis Phacolytic glaucoma:the lens cortex blocked the anterior chamber angle, or the lens nucleus dislocates into the anterior chamber or into vitreous body.,20,广西医科大学第一临床医学院眼科,nuclear cataract,It generally begins at the age of 40 It slowly progress Opacity starts at the embryonic or adult nucleus,EYE No.13,The density of the lens nucleus has been increased, the refractive index obviously strengthens, so myopia often appears.,21,广西医科大学第一临床医学院眼科,Nuclear opacity is grayish-yellow at first, then gradually becomes thick in yellowish-gray brown or brownish-black. In that time, the fundus cant be seen. The nuclear changes often continue unchanged for a long period(2030 years), uneasy to be matured.,22,广西医科大学第一临床医学院眼科,Subcapsular cataract