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Accommodation and PresbyopiaAccommodation and Presbyopia

Hermann vonHermann vonHelmholtz in 1855.Helmholtz in 1855.

Ronald A. Schachar,Ronald A. Schachar,MD, in 1994.MD, in 1994.

Schachar RA, Black TD, Kash RL, Cudmore DP, Schanzlin DJ.

The mechanism of accommodation and presbyopia in theprimate. Ann Ophthalmol. 1995;27:58-67

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Surgical Modalities of TreatmentSurgical Modalities of Treatment

of Presbyopiaof Presbyopia1.1. Anterior Ciliary sclerotomies with siliconeAnterior Ciliary sclerotomies with silicone

implants.implants.

2.2. MonovisionMonovision (LASIK, Conductive keratoplasty,(LASIK, Conductive keratoplasty,IOLs).IOLs).

3.3. MultifocalityMultifocality (LASIK, Phakic IOLs or pseudophakic(LASIK, Phakic IOLs or pseudophakic

IOLs)IOLs)

4.4. Accommodating IOLsAccommodating IOLs (Crystalens or 1(Crystalens or 1--CU)CU)

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ThirdThird--generation nongeneration non--reflective silicone materialreflective silicone material(Biosil).(Biosil).

Crystalens

High refractive index (RIHigh refractive index (RI= 1.430).= 1.430).

Contains an ultravioletContains an ultraviolet

(UV) filter.(UV) filter. Hinged adjacent to theHinged adjacent to theoptic and has small loopedoptic and has small loopedpolyimide haptics.polyimide haptics.

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The overall length of the lensThe overall length of the lensisis 11.5 mm11.5 mm (loop tip to loop tip(loop tip to loop tip

measurement)measurement).. The overall length asThe overall length asmeasured from the ends of themeasured from the ends of theplate haptics isplate haptics is 10.5 mm10.5 mm ..

The optic is biconvex and isThe optic is biconvex and is4.5 mm4.5 mm in diameter.in diameter.

The AThe A--constant isconstant is 119.0119.0..

Characteristics of

Crystalens

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Dynamic actionDynamic action

(Focus(Focus--Shift Principle)Shift Principle)

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Evidence Based MedicineEvidence Based Medicine

An increase in theAn increase in thevitreous pressure withvitreous pressure with

simultaneoussimultaneousdecrease in thedecrease in theanterior chamberanterior chamberpressure occurredpressure occurredupon directupon directstimulation of ciliarystimulation of ciliarymuscle in tenmuscle in tenprimates.primates.

Coleman J. On the hydraulic suspension theoryof accommodation. Trans Am Ophthalmol Soc.1986;846-868

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Evaluation of CrystalensEvaluation of Crystalens

Accommodating IOLAccommodating IOL

Protocol for submission of MD ThesisBenha Ophthalmology Department

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Exclusion criteria:Exclusion criteria: Keratometric cylinder more than 1 diopter.Keratometric cylinder more than 1 diopter. Bilateral congenital cataract.Bilateral congenital cataract. MicrophthalmosMicrophthalmos Previous ocular surgery.Previous ocular surgery.Anterior segment pathology.Anterior segment pathology. Incomplete or damaged zonules or aniridia.Incomplete or damaged zonules or aniridia. Uncontrolled glaucoma or visual field lossUncontrolled glaucoma or visual field losssecondary to glaucoma.secondary to glaucoma. Previous retinal detachment or pathology.Previous retinal detachment or pathology.

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All phaco cases aimed forAll phaco cases aimed forpostoperativepostoperative emmetropiaemmetropia and willand will

be operated in Ophthalmologybe operated in Ophthalmologydepartment indepartment in Benha UniversityBenha University

HospitalHospital and followed up forand followed up for

6 months.6 months.

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All the cases will beAll the cases will beimplanted with C&C visionimplanted with C&C vision

Crystalens IOL (ModelCrystalens IOL (ModelATAT--45)45)MultiMulti--piece Silicone platepiece Silicone plateshaped IOL.shaped IOL.

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Assessment of theAssessment of the

Accommodative amplitudeAccommodative amplitude

Subjectively.Subjectively. Objectively.Objectively.

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All these investigations should beAll these investigations should be

done in all visits:done in all visits:1mo1mo 3mo3mo 6mo6mo

UCVA for DistanceUCVA for Distance

Manifest RxManifest Rx BSCVA for DistanceBSCVA for Distance

UCVA for near (40cm)UCVA for near (40cm)

VA for near with DistantVA for near with Distantcorrection (40cm)correction (40cm)

AddAdd

BSCVA for near with AddBSCVA for near with Add

(40cm)(40cm)

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All these investigations should beAll these investigations should be

done in all visits:done in all visits:1mo1mo 3mo3mo 6mo6mo

Axial length + AC depthAxial length + AC depth

Axial length + AC depth withAxial length + AC depth withpilocarpine 1%pilocarpine 1%

Slit lamp examinationSlit lamp examination

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FutureFuture

Split double optics or combine the focusSplit double optics or combine the focusshift principle with shape change of theshift principle with shape change of the

optic.optic.

Smart lens ?!Smart lens ?!

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Thank youThank you