Disease Of The Lens

What is cataract? How to deal with it? Why the government all over the world want to control this disease? 1

2

EYE No.1

Disease of the lens Li Yonghua Department of Ophthalmology, Affiliated First Hospital of JiNing Medical College

3

EYE No.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.

4

• Anatomy: The lens is composed of lens capsule and lens fiber.

5

• Physiology of the lens – The lens is s kind of transparent and non-blood vessel tissue. – The lens’ nourishment are offered by aqueous humor.

6

• The disorder of the lens commonly if loss of its transparency (cataract ) and abnormality of its position; both can induce severe visual disturbance.

7

EYE No.4

Cataract • Cataract is the first cause of blindness in China and many other developing country. • There are one million of cataract sufferer who are in need of operation to restore their visions. 8

EYE No.5

Classification • According to the age of occurring: – Congenital cataract – Infantile cataract – Juvenile cataract – Adult cataract – Age-related cataract (senile) 9

• According to etiology: – Traumatic cataract : blunt or penetrating injury – Complicated cataract: uveitis – Metabolic cataract: diabetes – Drug-induced or toxic cataract – Developing cataract – After-cataract 10

EYE No.6

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. 11

Pat holog ic m echani sm • The disease is related with several factor: – Ultraviolet ray – Genetic factor – Systemic disease such as diabetes, hypertension. – Lens nourishment and metabolic condition 12

EYE No.7

• Clinical findings: – Bilateral disease – Fixed black spot before the eyes – Visual decrease without pain – Refractive change

13

EYE No.8

cl assificati on

Ac cor ding t o t he s it e wh ere cat aract beg ins t o f orm: Age-related cataract

cortical

nuclear

subcapsular

Anterior capsule

Posterior capsule 14

EYE No.9

corti cal catar ac t 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 isn’t affected, commonly without influencing vision. – To be diagnose after mydriasis under slitlamp examination. – To develop slowly 15

Incipient stage

16

EYE No.10

• Immature stage(intumescent stage) – The opacity gradually becomes obvious – Vision has obviously decreased – The fundus can’t be observed in – Some patient may induce acute attack of glaucoma due to shallow anterior chamber – Iris projection: the characteristic of this stage

17

• 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) 18

• Mature stage – The lens has become opaque at all in cream white color – The iris projection disappeared – The fundus can’t be looked in – Vision decreases to light perception or hand movement ， But the light seeking and color sensation are in normal. 19

• 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 20

• When the lens capsule ruptured – Phaco-anaphylactic uveitis – Phacolytic glaucoma

21

EYE No.13

nuclear cataract • It generally begins at the age of 40 • It slowly progress • Opacity starts at the embryonic or adult nucleus • The density 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 can’t be seen. • The nuclear changes often continue unchanged for a long period(20~30 years), uneasy to be matured.

23

Su bc aps ular cat ar ac t • According to the site where cataract begins to form – Posterior subcapsular cataract:common – Anterior subcapsular cataract:rare

24

• The opacity often occur to the posterior capsular center, so vision decreases in early stage. • The cataract may develop to become cortical opaque then total cataract.

25

Anterior subcapsular cataract 26

Tre at ment • There isn’t any effective drug to the age-related cataract. • It is major to operate.

27

Operat ive t ime • At the immature or mature stage • The vision is lower than 0.3 to influence with patient’s work and life

28

Pre ope rati ve e xam inati on • Systemic • Ocular part: – Exam visual acuity – Slit-lamp microscope – Corneal curvature – A/B ultrasonic exam 29

Oper ati ng m ethod • Phacoemulsification extraction of cataract – Characteristic: • transparent corneal incision(3.2mm) • To crush the hard lens nucleus to be chyloid with ultraemulsifier and extracted • To implant the foldable intraocular lens in the lens capsular bag 30

EYE No.18

Phaco+foldable IOL implantation

31

– strongpoint: • Self-healing wound • The corneal astigmatism after operation is fine • Visual restoration is soon

– Shortcoming: • The apparatus is expensive • Some descendible disease can’t choice this method • Too hard lens nucleus may not adopt this method 32

• Extracapsular cataract extraction(ECCE) and posterior chamber intraocular lens(IOL) implantation – – – –

The corneoscleral tunnel incision(6mm) dispense with suture The IOL is hard(unfoldable) The patient can get good vision soon after operation – The corneal astigmatism after operation is less. 33

EYE No.20

Two methods to extract the lens nuclear in ECCE 34

EYE No.21

Unfoldable IOL implantation

35

• Intracapsular cataract extraction – The incision is bigger than ECCE, so the corneal astigmatism is high. – The complications are more than that of ECCE

36

Vi su al co rr ect ion a ft er catar act ope rat ion • After cataract surgery, the aphakia is in a state of high hyperopia (+10~ +12 diopters) – By IOL: 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 patient 37

EYE No.26

conge nital c at ara ct • 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 mother’s or fetal systemic disorder. 38

Cl ini cal fi nd ings • 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, we can divided the disease into the next classes: 39

Anterior polar cataract 40

EYE No.28

– Perinuclear cataract

41

EYE No.29

• Nuclear cataract

42

EYE No.30

• Total cataract

43

EYE No.31

treatment Whether or not affect with the vision

not

Observed

affect Surgery in time

44

EYE No.32

• 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 3~6 months. – But the IOL implantation must do after 3 years old. 45

• Treatment purpose: – Reserve vision – Prevent amblyopia – Promote development of fusion function

• Surgery method – Extracapsular cataract extraction – Cataract suction – IOL implantation after the suction’s patient is 3 years old 46

• The correction: – By glasses – By contact lens – By IOL – Amblyopia should be treated actively and timely.

47

EYE No.33

Tra um at ic c ata rac t

48

Drug-induced cataract 49

Toxic cataract 50

Ecto pi a l enti s • lens’ positional abnormality has two causes: – Rupture of suspensory ligament induced by injury – Congenital aplasia or weakness and laxation of the ligament

51

Ectopia lentis(dislocate into the anterior chamber, vitreous cavity or incarcerated at the pupillary area) 52

EYE No.40

The lens dislocates into the anterior chamber

53

EYE No.41

Subluxation of the lens 54

• Subluxation of the lens is often occurs in Marfan’s syndrome patient

55

Subluxation of the lens is often occurs in Marfan’s syndrome patient （ palm ） 56

Tre at ment • The lens is extracted when the vision is affected or the complications occurred.

57

EYE No.43

Pre vention and tre atment of bl in dness • Blindness also indicates that both eyes lose the ability to distinguish surroundings,the patient isn’t able to be competent at some occupations, even to take care of himself.

58

• 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 is more than 0.05, but lower than 0.3. 59

EYE No.44

Tabl e:c riteri on of clas sifi ca tion of l ow vision an d bl indnes s(WH O, 1973 ) Best corrected vision Best vision lower than

Low vision

1 2 Blindn 3 ess 4 5

0.3 0.1 0.05 0.02

Lowest vision equal to or lower

0.1 0.05(FC/3m) 0.02(FC/1m) Light perception No light perception 60

EYE No.45

severa l m aj or oph th almopath ies ca us ing bl indnes s

• • • • •

Cataract: the first cause Keratopathy Glaucoma Trachoma Eye injury and occupation ophthalmopathy • Genetic ophthalmopathy • Diabetic retinopathy

61

62