1、1EYE No.12Anatomy 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.23 Anatomy:The lens is composed of lens capsule and lens fiber.The lens capsule is a layer of elastic homogeneous me
2、mbrane.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 only can views the center portion
3、through the pupil.)5 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.6 The disorder of the lens commonly if loss of its transparency(cataract)and abnormalit
4、y of its position;both can induce severe visual disturbance.7Cataract 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.48Classification According to the age of o
5、ccurring:Congenital cataract Infantile cataract Juvenile cataract Adult cataract Age-related cataract(senile)EYE No.59 According to etiology:Traumatic cataract:blunt or penetrating injury Complicated cataract:uveitis Metabolic cataract:diabetes Drug-induced or toxic cataract Developing cataract Afte
6、r-cataract10age-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.611Pathologic mechanismPathologic mechanism The disease is related with several factor:Ultraviolet ra
7、y Genetic factor Systemic disease such as diabetes,hypertension.Lens nourishment and metabolic condition12 Clinical findings:Bilateral disease Fixed black spot before the eyes Visual decrease without pain Refractive changeEYE No.713classificationclassificationAccording to the site where cataract beg
8、ins According to the site where cataract begins to form:to form:corticalAnterior capsulePosterior capsulesubcapsularAge-related cataractEYE No.8nuclear14cortical cataractcortical cataractIt is divided into 4 stages:Incipient stage:To begin opacity appears at the periphery of anterior and posterior c
9、ortex 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 slowlyEYE No.915EYE No.10 Immature stage(intumescent stage)The opacity gradually becomes obvious The cortex absorbs water t
10、o 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 16 Iris projection:To examine with oblique illumination,the iris shadow on projected side f
11、alls 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)17 Mature stage The lens has become opaque at all in cream white color The iris projection disappeared The fundus cant be look
12、ed in Vision decreases to light perception or hand movement But the light seeking and color sensation are in normal.18 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 anter
13、ior chamber deepens with iridodonesis.Vision may increase suddenly19 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 ruptured Phaco-anaphylactic u
14、veitis Phacolytic glaucoma:the lens cortex blocked the anterior chamber angle,or the lens nucleus dislocates into the anterior chamber or into vitreous body.21nuclear cataract It generally begins at the age of 40 It slowly progress Opacity starts at the embryonic or adult nucleusEYE No.13 The densit
15、y of the lens nucleus has been increased,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 unc
16、hanged for a long period(2030 years),uneasy to be matured.23Subcapsular cataractSubcapsular cataract According to the site where cataract begins to form Posterior capsular cataract:common Anterior capsular cataract:rare24 The opacity often occur to the posterior capsular center,so vision decreases i
17、n early stage.The cataract may develop to become cortical opaque then total cataract.25TreatmentTreatment There isnt any effective drug to the senile cataract.It is major to operation.26Operative timeOperative time At the immature or mature stage The vision is lower than 0.3 to influence with patien
18、ts work and life27Preoperative examinationPreoperative examination Systemic Ocular part:Exam visual acuity Slit-lamp microscope Corneal curvature A/B ultrasonic exam28Operating methodOperating method Phacoemulsification extraction of cataract Characteristic:transparent corneal incision(3.2mm)To crus
19、h the hard lens nucleus to be chyloid with ultraemulsifier and extracted To implant the foldable intraocular lens in the lens capsular bag29 strongpoint:Self-healing wound The corneal astigmatism after operation is fine Visual restoration is soon Shortcoming:The apparatus is expensive Some descendib
20、le disease cant choice this method Too hard lens nucleus may not adopt this method30 Extracapsular cataract extraction and posterior chamber intraocular lens implantation The corneoscleral tunnel incision(6mm)dispense with suture The lens is hard(unfoldable)The patient can get good vision soon after
21、 operation The corneal astigmatism after operation is less.31 Intracapsular cataract extraction The incision is bigger than ECCE,so the corneal astigmatism is high.The complications are more than that of ECCE32Visual correction fater Visual correction fater cataract cataract operationoperation After
22、 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 aphakia By contact lens:the method is less used because of more complications and using process more trouble By glasses:binocular aphakia patient33congn
23、italcongnital cataract cataract Definition:congenital cataract is a result of lens growing and developing disturbance in the process of fetal development.Causes:Endogenous:chromosome with heredity.Exogenous:by mothers or fetal systemic disorder.EYE No.2634Clinical findingsClinical findings It common
24、ly 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 cataract Posterior cataract Perinuclear cataract Nuclear cataract Total cataract,and so on35treatment Whether or not affect with the vision notObserve
25、daffectSurgery in timeEYE No.3136 Opportunity of operation:the earlier the operation is done,the greater the chance to get good vision becomes.The surgery may be done some 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.E
26、YE No.3237 Treatment purpose:Reserve vision Prevent amblyopia Promote development of fusion function Surgery method Extracapsular cataract extraction Cataract suction IOL implantation after the suctions patient is 3 years old38 The correction:By glasses:suitable to binocular aphakia with elder age.I
27、t 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 years,the patient can do the implantation to obtain better vision.Amblyopia should be treated actively and timely.39Traumatic catara
28、ctEYE No.33Drug-induced cataractToxic cataract40Ectopia lentisEctopia lentis lens positional abnormality has two causes:Rupture of suspensory ligament induced by injury Congenital aplasia or weakness and laxation of the ligament41 Subluxation of the lens is often occurs in Marfans syndrome patient42
29、TreatmentTreatment The lens is extracted when the vision is affected or the complications occurred.43Prevention and treatment of blindnessPrevention and treatment of blindness Blindness also indicates that both eyes lose the ability to distinguish surroundings,the patient isnt able to be competent a
30、t some occupations,even to take care of himself.EYE No.4344 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 of better eye is more than 0.05.The low vision:the best corrected vision of better eye i
31、s more than 0.05,but lower than 0.3.45Table:criterion of classification of Table:criterion of classification of low vision and blindness(WHO,1973)low vision and blindness(WHO,1973)Best corrected vision Best vision lower than Lowest vision equal to or lower 1 0.3 0.1 Low vision 2 0.1 0.05(FC/3m)3 0.0
32、5 0.02(FC/1m)4 0.02 Light perception Blindness 5 No light perception EYE No.4446several major ophthalmopathiesseveral major ophthalmopathies causing blindnesscausing blindness Cataract:the first cause Keratopathy Glaucoma Trachoma Eye injury and occupation ophthalmopathy Genetic ophthalmopathy Diabetic retinopathy EYE No.45
