1、1,Disease of the lens,EYE No.1,2,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.2,3,Anatomy: The lens is composed of lens capsule and lens fiber. The lens capsule is a la
2、yer of elastic homogeneous membrane. The lens fibers are the extension and elongation forwards and backwards of the epithelial cells at the equator.,4,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 o
3、nly can views the center portion through the pupil.),5,Physiology of the lensThe 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.,6,The disorder of the lens commonly if loss of its t
4、ransparency (cataract ) and abnormality of its position; both can induce severe visual disturbance.,7,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.
5、4,8,Classification,According to the age of occurring:Congenital cataractInfantile cataractJuvenile cataractAdult cataractAge-related cataract (senile),EYE No.5,9,According to etiology:Traumatic cataract : blunt or penetrating injuryComplicated cataract: uveitisMetabolic cataract: diabetesDrug-induce
6、d or toxic cataractDeveloping cataractAfter-cataract,10,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.6,11,Pathologic mechanism,The disease is related with
7、several factor:Ultraviolet rayGenetic factorSystemic disease such as diabetes, hypertension.Lens nourishment and metabolic condition,12,Clinical findings:Bilateral diseaseFixed black spot before the eyesVisual decrease without painRefractive change,EYE No.7,13,classificationAccording to the site whe
8、re cataract begins to form:,cortical,Anterior capsule,Posterior capsule,subcapsular,Age-related cataract,EYE No.8,nuclear,14,cortical cataractIt is divided into 4 stages:,Incipient stage: To begin opacity appears at the periphery of anterior and posterior cortexThe center lens is almost clear, the p
9、upillary area isnt affected, commonly without influencing vision.To be diagnose after mydriasis under slit-lamp examination.To develop slowly,EYE No.9,15,EYE No.10,Immature stage(intumescent stage)The opacity gradually becomes obviousThe cortex absorbs water to become swollenIris projection: the cha
10、racteristic of this stageVision has obviously decreasedThe fundus cant be observed inSome patient may induce acute attack of glaucoma due to shallow anterior chamber,16,Iris projection:To examine with oblique illumination, the iris shadow on projected side falls on opaque cortex in deep layer, a cre
11、scent projection appears at the pupil of the side.( because there is transparent cortex between iris pupillary margin and lens cortex),17,Mature stageThe lens has become opaque at all in cream white colorThe iris projection disappearedThe fundus cant be looked inVision decreases to light perception
12、or hand movementBut the light seeking and color sensation are in normal.,18,Hypermature stageWhen 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.Visi
13、on may increase suddenly,19,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.,20,When the lens capsule rupturedPhaco-anaphylactic uveitisPhacolytic glaucoma:the lens cor
14、tex blocked the anterior chamber angle, or the lens nucleus dislocates into the anterior chamber or into vitreous body.,21,nuclear cataract,It generally begins at the age of 40It slowly progressOpacity starts at the embryonic or adult nucleus,EYE No.13,The density of the lens nucleus has been increa
15、sed, the refractive index obviously strengthens, so myopia often appears.,22,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 y
16、ears), uneasy to be matured.,23,Subcapsular cataract,According to the site where cataract begins to formPosterior capsular cataract:commonAnterior capsular cataract:rare,24,The opacity often occur to the posterior capsular center, so vision decreases in early stage.The cataract may develop to become
17、 cortical opaque then total cataract.,25,Treatment,There isnt any effective drug to the senile cataract.It is major to operation.,26,Operative time,At the immature or mature stageThe vision is lower than 0.3 to influence with patients work and life,27,Preoperative examination,SystemicOcular part:Exa
18、m visual acuitySlit-lamp microscopeCorneal curvature A/B ultrasonic exam,28,Operating method,Phacoemulsification extraction of cataractCharacteristic:transparent corneal incision(3.2mm)To crush the hard lens nucleus to be chyloid with ultraemulsifier and extractedTo implant the foldable intraocular
19、lens in the lens capsular bag,29,strongpoint:Self-healing woundThe corneal astigmatism after operation is fineVisual restoration is soonShortcoming:The apparatus is expensiveSome descendible disease cant choice this methodToo hard lens nucleus may not adopt this method,30,Extracapsular cataract extr
20、action and posterior chamber intraocular lens implantationThe corneoscleral tunnel incision(6mm)dispense with sutureThe lens is hard(unfoldable)The patient can get good vision soon after operationThe corneal astigmatism after operation is less.,31,Intracapsular cataract extractionThe incision is big
21、ger than ECCE, so the corneal astigmatism is high.The complications are more than that of ECCE,32,Visual correction fater cataract operation,After cataract surgery, the aphakia is in a state of high hyperopia (+10 +12 diopters)By intraocular lens: it is the most effective method for correction of ap
22、hakiaBy contact lens: the method is less used because of more complications and using process more troubleBy glasses: binocular aphakia patient,33,congnital cataract,Definition: congenital cataract is a result of lens growing and developing disturbance in the process of fetal development.Causes:Endo
23、genous:chromosome with heredity.Exogenous:by mothers or fetal systemic disorder.,EYE No.26,34,Clinical findings,It commonly is bilateral, static.A few develop continuously after birth.It may be classified according to the site and the shape of lens opacity.Anterior polar cataractPosterior cataractPe
24、rinuclear cataractNuclear cataractTotal cataract, and so on,35,treatment,Whether or not affect with the vision,not,Observed,affect,Surgery in time,EYE No.31,36,Opportunity of operation: the earlier the operation is done, the greater the chance to get good vision becomes.The surgery may be done some
25、weeks after birth.It should be done generally in baby with age of 36 months.But the IOL implantation must do after 3 years old.,EYE No.32,37,Treatment purpose:Reserve visionPrevent amblyopia Promote development of fusion functionSurgery methodExtracapsular cataract extractionCataract suctionIOL impl
26、antation after the suctions patient is 3 years old,38,The correction:By glasses:suitable to binocular aphakia with elder age. It is simple and convenient, easy to adjust and replace.By contact lens：suitable monocular aphakia in children. But it is troublesome to take off, and so on. By IOL:After 3 y
27、ears,the patient can do the implantation to obtain better vision.Amblyopia should be treated actively and timely.,39,Traumatic cataract,EYE No.33,Drug-induced cataract,Toxic cataract,40,Ectopia lentis,lens positional abnormality has two causes:Rupture of suspensory ligament induced by injury Congeni
28、tal aplasia or weakness and laxation of the ligament,41,Subluxation of the lens is often occurs in Marfans syndrome patient,42,Treatment,The lens is extracted when the vision is affected or the complications occurred.,43,Prevention and treatment of blindness,Blindness also indicates that both eyes l
29、ose the ability to distinguish surroundings,the patient isnt able to be competent at some occupations, even to take care of himself.,EYE No.43,44,Blindness: the best corrected visual acuity of better eye is lower than 0.05,or the visual field is less than 10 degrees while the best corrected vision o
30、f better eye is more than 0.05.The low vision:the best corrected vision of better eye is more than 0.05, but lower than 0.3.,45,Table:criterion of classification of low vision and blindness(WHO,1973),EYE No.44,46,several major ophthalmopathies causing blindness,Cataract: the first causeKeratopathy Glaucoma Trachoma Eye injury and occupation ophthalmopathy Genetic ophthalmopathy Diabetic retinopathy,EYE No.45,
