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Lens diseases

Lens diseases. Wen Xu Eye Center, 2nd Affiliated Hospital Zhejiang University. The most common cause of painless, progressive loss of vision today is. ?. Cataract. Anatomy of the lens. Location posterior to iris anterior to vitreous Shape biconvex Structure lens capsule

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Lens diseases

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  1. Lens diseases Wen Xu Eye Center, 2nd Affiliated Hospital Zhejiang University

  2. The most common cause of painless, progressive loss of vision today is ?

  3. Cataract

  4. Anatomyofthelens • Location posterior to iris anterior to vitreous • Shape biconvex • Structure lens capsule lens cortex lens nucleus

  5. Physiology of the lens • No vessel, nerve and transparent. • Derive nutrients from the aqueous humor • Significant refractive medium • Accommodative function • No immediate relation with adjacent tissues • Complex metabolism • Simple disorders: transparency and location change

  6. Cataract • Definition: opacification of the lens • epidemiology: clinical cataract corrected vision<0.5

  7. Cataract Mechanism: many factors lens capsular damage osmosis increase,loss of protective screen,metabolic disorders protein degeneration,cell apoptosis lens opacify cataract

  8. Cataract Classification: • by cause: congenital, senile(age-related), complicated, metabolitic, drug-induced, toxic, traumatic, secondary • by age:congenital, acquired • by location: cortical, nuclear, subcapsular • by shape: dot-like, coronary, lamellar • by degree: immature, intumescent, mature, hypermature

  9. Cataract Symptoms: • decreased vision: most obvious and important • decreased contrast sensitity • refractive error: myopia,astigmatism • monocular diplopia or multiple vision • glare: scattered light rays • poor color discrimination:blue spectrum

  10. Cataract Signs: The lens is best examined with the pupil dilated. A magnified view of the lens can be obtained with a slit-lamp or by using the direct ophthalmoscope with a high plus (10+) setting

  11. Cataract Grade’s standards of nuclear hardness: Ⅰ transparent,no nucleus,soft Ⅱ yellow-white or yellow,soft Ⅲ dark yellow,moderate hard Ⅳ brown or amber, hard Ⅴ brown or black,extremely hard

  12. (I) Age-related cataract Description: the most common type, most patients are beyond their 50’s. The incidence goes up with aging. It is the first rank of ophthalmic diseases leading to blindness Risk factors: Many factors are involved include age, occupation, sex, ultraviolet radiation, diabetes, hypertension, positive family history, nutritious condition

  13. (i) Cortical Cataract • The most common type • Four stages: (1) incipient stage (2) intumescent stage or immature stage (3) mature stage (4) hypermature stage

  14. 1. incipient stage Features: a、cuneiform(楔形['kjunɪə,fɔrm]) opacity b、lamellar seperate c、vacuole d、cracks e、no vision damage Tests:a、slit-lamp b、transillumination

  15. 2. intumescent stage or immature stage Features: a、more serious opacity b、larger volume and more shallow anterior chamber c、iris shadow d、obvious vision decrease e、myopia Tests:a、slit-lamp b、oblique illumination Matter needs attention: angle-closure glaucoma

  16. 3. mature stage Features: a、complete opacity, milky white, iris shadow disappear b、volumn and anterior chamber regain normal c、vision: LP or HM before the eye Tests:a、slit-lamp b、flashlight

  17. 4. hypermature stage Features: a、smaller volumn,wrinkled lens capsule,claybank and fallen nucleus (Morgagnian cataract) ,superior of anterior chamber deepens while inferior is the opposite,ridodonesis. b、laceration of lens capsule,lens luxation. c、phacoanaphylactic uveitis,phacolytic glaucoma

  18. (ii) Nuclear Cataract Features: a、start earlier,generally on 40’s,slowly progressive, not likely to be mature. b、nuclear opacity: start by embryonic nucleus. c、vision: no vision damage early on, myopia Tests:slit-lamp、 transillumination、 oblique illumination

  19. (iii) Subcapsular Cataract Features: a、start earlier b、posterior subcapsular cataract: cause obvious vision defect early on c、cupuliform(杯状) opacity of posterior pole

  20. (II) Congenital Cataract Features: present at birth or appear shortly thereafter; unilateral or bilateral; may be alone or associated with other ocular or systemic congenital abnomalities Etiology: (1) hereditary factors(chromosome,gene) (2) environmental factors (matrix disease) when pregnance <3 m: virus infection; drugs,metabolic diseases (3) undetermined causes

  21. Classification According to location, form and degree • anterior polar cataract • posterior polar cataract • perinuclear cataract • coronary cataract • punctate cataract • total cataract • membrane cataract • nuclear cataract

  22. Congenital cataract

  23. Anterior polar cataract

  24. Posterior polar cataract

  25. Perinuclear cataract

  26. Coronary cataract

  27. Punctate cataract

  28. Total cataract

  29. Membrane cataract

  30. Nuclear cataract

  31. (III) complicated cataract Features: ocular inflammation or degenerative disorders→ nutritious or metabolic defect → lens opacity Common causes: corneal ulcer, glaucoma, uveitis,retinal detachment, retinitis pigmentosa, intraocular tumor,high myopia, etc.

  32. Clinical findings: 1. primary disease changes 2. cataract Treatment: 1. treat the primary disease. 2.do the surgery after 3 m of inflammation control

  33. (IV) Metabolic cataract • Diabetic cataract • Galactose cataract: lack of enzyme • Tetany cataract: low blood calcium • Wilson’s disease (Hepatolenticular Degeneration): KF ring, sunflower-shaped opacity,copper.

  34. 1. Diabetic cataract • Mechanism: blood sugar↑ →sugar in the lens↑ → change into sorbitol→plasma osmotic pressure↑ →absorb water→fibers swellen and degenerate→lens opacity

  35. classification: (1) real diabetic cataract (2) age-related cataract of diabetic patients • Clinical findings: (1) the first type: teenagers,bilateral,rapidly progressive,eading to total cataract,combined with refractive changes according to blood sugar (2) the second type: high incidence,start earlier, fast progressive, easy to be mature,similar with senile cortical cataract

  36. Treatment: (1) positively treat diabetes,control blood sugar (2) do the surgery if permitted (3) positively postoperational infection and bleeding prevention

  37. (V) Drug-induced and toxic cataract • Corticosteroid cataract • Chlorpromazine cataract • Miotic cataract • Trinitrotoluence cataract • Metals

  38. Trinitrotoluence cataract

  39. (VI) Traumatic cataract • Classification: Contusive cataract Penetrating cataract Chemical injuries cataract Radiation cataract Electric cataract • Treatment: observation or surgery

  40. (VII) Secondary cataract • Definitions: opacification of the posterior capsule due to partially absorbed traumatic cataract or following extracapsular cataract extraction (posterior capsular opacification). It is the most common complication of cataract surgery • Clinical findings: vision decrease after cataract surgery; Elschnig’s pearls

  41. It is a significant problem in almost all pediatric patients unless the posterior capsule and anterior vitreous are removed at the time of surgery. Up to 30%-50% of all adult patients develop an opaque secondary membrane after cataract surgery • Treatment: neodymium:YAG capsulotomy

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