Accommodative IOL’s Dr. H. Razmjoo Isfahan University of Medical Sciences
Achieving the Desired Results in modern cataract surgery: • Astigmatism Control • Aspheric Optics • Accurate Biometry • Appropriate Formulas • Adjusting the Outcome • Accommodation
Presbyopia : Solutions? • Sclera?/ • Cornea • Presbyopic LASIK • Corneal Inlays • Lens • Multifocal IOL • Phakic / pseudophakic • Accommodative IOL
Consider this issues in evaluating presbyopic Surgery: Measuring accommodation True versus Pseudo-Accommodation Reading ease, speed Accommodative reserve Quality of vision - HOAs
True vs Pseudo-accommodation True Accommodation - Transient and rapidly reversible change in optical power of the eye - Generally requires IOL change of shape or position Not associated with loss of contrast sensitivity • Pseudo-accommodation • - First devices available • - IOLs • Refractive – ReZoom • Diffractive – ReSTOR • Associated with loss of contrast sensitivity
Present IOLs – (FDA) • Monofocal • Pseudoaccommodative • Multifocal • ReSTOR • ReZoom • Accommodative • Crystalens
Monofocal IOLs: • Excellent visual acuity • Best contrast sensitivity • Need for some glasses • Monovision
Multifocals: (ReStor / ReZoom) • Good for some… • Few years experience • Excellent visual acuity • Decreased contrast sensitivity
Accommodative: • Crystalens • Excellent quality of vision • Minimal contrast loss • Very poor true accommodation • 1-1.5D • PCO • Future ??? • Only 26% spectacle free in some studies
Future accomodating IOL’s • Based on accommodation theories • Exact method controversial • Helmhotz’s theory Ciliary M. contraction Decreased zonular tension Thicker lens Bag more lax More PLUS power
Accommodative IOLs • Future of refractive surgery • FDA approved lens has limited accommodation • Small incision IOL • Truly accommodation will be available when : • Right IOL concept / design • Maintained long term flexibility of capsule
Accommodative Models • Lens “filling” • Deformable IOL • Single optic • Dual optic
Single optic IOL • Hinged haptics • Forward movement > effective power of IOL • Poor accommodation • Need 1.5 mm axial move to achieve 2 D ofaccommodation
Dual optic IOL • Positive lens anterior / negative lens posterior • Lenses connected with spring like pieces • Accommodation through ciliary body contraction induced separation of lenses • Large area required
Dual optic IOL • Advantage over single optic • More accommodation • Less IOL movement required • No glare or contrast issues • Inter-lenticular opacities ? Accommodation
Single optic:Crystalens • Only FDA approved
The capsulorhexis must always be larger than the optic of the IOL, i.e. a capsulorhexis of 6 mm must be selected for an IOL optic of 5 mm. The anterior capsular bag must be placed outside the optic.
When the lens is placed in the capsular bag, it must be pushed backward until there is complete contact with the posterior capsular bag. At this stage of the surgery, the IOL should not move forward at all; which may cause Z syn.
The IOL must be rotated until it fits exactly. Then the cortex and the viscoelastic substance behind the IOL optic must be carefully removed. Finally, the IOL must be pressed completely back onto the posterior capsular bag and may not move forward.
no accommodate for 3 to 5 days The polyimide material of the haptics causes the IOL to grow firmly together with the capsular bag by fibrosis. At this stage it is important that the patient does not accommodate during the first 3-5 days after implantation.
Atropine To avoid premature accommodation, the pupil is dilated after surgery with a single dose of atropine and it takes 3-5 days for this accommodation blockade to abate.
Indication: This IOL would be appropriate for all patients.
The FDA approved Eyeonics Inc.’s accommodating IOL, Crystalens AT-45, in November 2003. Bausch & Lomb acquired Crystalens in 2008 and introduced a newer model called Crystalens HD in 2008. Crystalensis the only FDA-approved accommodating IOL currently on the market
Studies and Peer Reviews: • In a September 2004 FDA trial involving 325 patients: • 100% could see at intermediate distances (24" to 30") without glasses; the distance for most of life's activities • 98.4% could see well enough to read the newspaper and the phone book without glasses. • Some patients did require glasses for some tasks after implantation of the crystalens
At this time, there is no long-term, well-designed clinical trials to support the accommodating technology of the Crystalens IOL.
Single optic: 1 CU (Human Optics) • 4 flexible haptics for axial movement
Single optic:BioConfold 43 E (Morcher) • Ring haptics for optic movement
Single optic: Opal (B&L) Currently in clinical trials
Single optic:Tetraflex (Lenstec) • Depends on axial move
Single optic: Fluid vision (Power Vision) • Dynamic Optic with Fixed Haptics • Up to 10 D accommodation • Accommodation driven hydraulic lens shape change NON-ACCOMMODATED ACCOMMODATED
Single optic:Flex optic (AMO) • Conforms the capsular bag • Changes optic curvature • No axial movement • In trial
“Single optic”:NuLens (Nulens) • Flexible polymer between 2 rigid plate, one with an opening • Polymer bulges = more positive lens • 30 - 50 D of accommodation theoritically