眼科学：08 Lens Disease

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1、Lens Disease1Lens Anatomy大小大小位置位置特点特点2Lens Function1.Refraction2.Accommodation3Lens Function-Refraction Cornea:refractive power: 43D (70%)refractive index: n=1.377 Lens:refractive power: 20Drefractive index: n=1.437 (nucleuscortex)4Lens Function- AccommodationobjectsCiliary muscleZonular fiber Shape

2、 of lensfarrelaxtensionflattennearcontractrelaxationspherical5Why the lens is transparent?1.lens fibers arrange in order2.high concentration of lens proteinu Pump-leak system Na+ 2025 mmol/L K+ 120150mmol/L Na+-K+ATP 6Lens Disease Lens opacity : cataract Location change : ectopia lentis dislocated l

3、ens7Cataract Cataract major cause of blindness Chinas 2001 census in the population of over 60 yrs was about 42.8% prevalence rateVision Action 2020 (the right to sight): eliminate the main causes of avoidable blindness by the year 2020 8Classfication of cataractAccording to etiology :1. congenital

4、cataract2. age-related cataract (senile cataract)3. complicated cataract4. traumatic cataract5. drug-induced cataract6. after cataract7. cataract associated with systemic disease: diabetes mellitus, hypoparathyroidism, galactosemia, atopic dermatitis Lowes, Werners, Downs syndromes 9 Age-related cat

5、aract (senile cataract) ARC101112Symptoms Blurred vision for both near and distance without pain Reduced intensity of colors Vision field defects Hazy Glare Double vision Increased difficulty seeing at night Change in the eyes refractive error Second Vision （myopia increased）13View of cataract patie

6、nt14Age-related cataract(senile cataract)Etiology: Ultraviolet radiation Diabetes mellitus Drugs Smoking Alcohol Nutritional deficiency1515Age-related cataract(senile cataract)Mechanism:Oxidative DamageFree radicalsMolecular chaperone of -crystallinApotosis16Classfication of senile cataract 1.nuclea

7、r cataract located in the center of the lens. 2.cortical cataract affects the layer of the lens surrounding the nucleus 3.posterior subcapsular cataract the back outer layer of the lens1717LOCS （lens opacities classification system) LOCS LOCS C1-5 NO1-6C1-6 P1-518Emery Nuclear hardness - 19Cortical

8、cataract 20Age-related cataract(senile cataract)Development of cortical cataract1.Incipient stage2.Intumescent stage (immature stage)3.Mature stage4.Hypermature stage morgagnian cataract phacoanaphylactic uveitis phacolytic glaucoma2121Cataract- incipient stage2222Cataract- immature stage23Cataract-

9、 mature stage24morgagnian cataract25Nuclear cataract High myopia, at 40 years Develop slowly at early stage Early stage: improve near vision Advanced stage: Extreme decline of vision26Nuclear cataract27Posterior subcapsular cataract Located in the cortex near the central posterior capsule, may invol

10、ve the visual axis Common symptoms: glare, reduced vision under bright lighting 28Posterior subcapsular cataract29Posterior subcapsular cataract30Treatment2931Treatment Medicine NO!3032Treatment Surgery:1.Couching procedure (600 B.C18th century) Acupuncture2.Intracapsular cataract extraction, ICCE (

11、Samuel Sharp, 1753, London)3.Extracapsular cataract extraction, ECCE (Jacques Daviel, 1748, French)4.Phacoemulsification (Charles Kelman, 1967, USA)33How about aphakia ? High hyperopia34Refractive correction for aphakia eye1.Glasses2.Corneal contact lens3.Intraocular lens implantation35Treatment Int

12、raocular lens implantation (Harold Ridley, 1949, British)3637Phacoemulsification + IOL implantation38Femtosecond laser-assisted cataract surgery Corneal insicion CCC Nuclear management39Pre-surgery Evaluation Lens Opacity Visual acuity measurement Retina color vision and light perception Others (A，B

13、-SCAN R etc) WHY?40IOL calculations Axial length Corneal Radius Anterior Chamber Depth Lots of formula SRK-T Holladay Haigis 41 after surgery42Complications1. Rupture of posterior capsule2. IOL3. Corneal astigmatism4. Posterior capsule opacity5. Posterior segment injury, bleed, RD6. Endophthalmitis7

14、. Others4344Posterior capsule opacity45After cataract4246After cataractDue to regeneration of lens epithelial cellsSignificant problem for childhood cataract, The Nd:YAG laser: a noninvasive method for discission of the posterior capsule47IOL types PMMA Foldable IOL Acrylic Silicone Hema Functions Aspherical Monofocal Multifocal Accommodative Toric Yellow-natural Heparin-modified Irisdiaphram etc 48复习题复习题 晶状体主要生理功能晶状体主要生理功能 白内障有哪些类型白内障有哪些类型 老年性白内障分几期，几类型老年性白内障分几期，几类型 老年性白内障手术时机老年性白内障手术时机 目前主要治疗方法目前主要治疗方法 白内障手术后视力主要相关因素白内障手术后视力主要相关因素last49