Monovision

MonovisionMonovision

Monovision

• This optical condition allows the relief of presbyopia symptoms.– one eye is corrected for distance vision– The other eye is corrected for near vision

• Goal of treatment– To give patients clear vision both near and

far

Concept

• Intention to produces anisometropic blur – the image in one eye is focused while the

image in the other eye is defocused.– Suppress blur in nondominant eye will be

easier than in dominant eye.

• Person'€™s brain learns to use the distance focused eye for distance viewing and the near focused eye for near viewing

Monovision

• Dominant eye corrected for distance vision

• Nondominant for near vision

• Induced anisometropic 1.25- 2.5 dipoters

• Mini monovision lower level of myopia for near vision -0.5 to -0.75 D

Ocular dominanceOcular dominance

Ocular dominanceOcular dominanceOcular dominanceOcular dominance

MotorMotorMotorMotor

Pointing-a-finger testPointing-a-finger testHole- in- card testHole- in- card testPointing-a-finger testPointing-a-finger testHole- in- card testHole- in- card test

Binocular rivalry targetBinocular rivalry targetStereodisparate objectsStereodisparate objectsBinocular rivalry targetBinocular rivalry targetStereodisparate objectsStereodisparate objects

sensorysensorysensorysensory

Seijas O, Liano P, Liano R, Roberts C, Piedrahita E, Diaz E. Ocular Dominance Diagnosis and Its Influence in Monovision. Am J Ophthalmol.2007;144:209–16.

MotorMotor testtest

Seijas O, Liano P, Liano R, Roberts C, Piedrahita E, Diaz E. Ocular Dominance Diagnosis and Its Influence in Monovision. Am J Ophthalmol.2007;144:209–16.

Ocular dominanceOcular dominance

• Ogle’s eye dominance test

x

x x x

o

o o o

Method

• Test dominant eye

• Refraction– Dominant Full correction for distance vision– Nondomiant Myopia undercorrection

Hyperopia overcorrection

• Trial Lens or CL trial at home

adaptation period should be greater than 2-3 wks

How is monovison obtained?

• Contact lenses

• Refractive surgery

• Conductive Keratoplasty

• Corneal inley

• IOL

Refractive surgery

• Multifocal corneal ablationo A small central steep zoneo Inferior near zone ablation patterno Inferior decentered hyperopic ablationoCentral distance ablation with

intermediate/near midperipheral abration

Patterns of Multifocal Ablation

Near

Far

Near

Far

Far

Near

Conductive Keratoplasty

• Nonablation collagen-shrinking procedure approve for correction low level of hyperopia ( +0.75 - + 3.25 D)

• Radiofrequency(RF) energy is delivered through tip into peripheral corneal stroma

Intracorneal Inlays

• Lamellar corneal flap created (8.0mm and 160µm)• Placing a biocompatible polymer lens in the central

cornea over pupil

Corneal inley

• ProsExtraocularEasy to do Easy to reverse

• ConsInvolves visual axisAdversely effects distance vision in emmetropesCases of epithelial ingrowth resulting in thinning

and melt of flap

Intraocular lens

• Multifocal IOL

• Monofocal IOL ( Monovision)

Monovision

• Success rate mean 76%

Depend onDepend on

• Ocular dominance and sighting preference

• Interocular suppression of blur

• Age

• Stereoacuity

• phorias

Jain S, Arora I, Azar D. Success of Monovision in Presbyopes: Review of theLiterature and Potential Applications

toRefractive Surgery. Surv Ophthalmol.1996;40:491-99.

Patient selection

• Best candidate are myopic patient over the age of 40

• Age & near addition of the patient can be predictive of success

• Visual needs & lifestyle, occupation, patient’s expectation

Advantages

• Correct presbyopia glass free

• Functional vision at distance and near

Disadvantages of Monovision

• ↓ in visual acuity, stereopsis, depth perception, contrast sensitivity

• Difficulty in seeing clearly at an intermediate distance

• Driving is compromised, especially at night

• Distance and near ghosting (incomplete suppression of interocular blur)

Modified monovision

• Dominant eye distance vision

• Nondominant eye bifocal Lens near and intermediate distance

Modified trivision• Dominant eye distance vision + low add

power for intermediate distance

• Nondominant eye bifocal Lens near and intermediate distance

Varies Forms and Examples of Modified Monovision

Distance EyeDistance Eye Near eyeNear eye

Single-vision lens Bifocal lens power biased toward near vision

Bifocal lens power biased toward distance vision

Bifocal lens power biased toward near vision

Large OZ for distance/center Small OZ for distance/center

Small OZ for near/center Large OZ for near/center

Varies Forms and Examples of Modified Monovision

Distance EyeDistance Eye Near eyeNear eye

distance/center concentric or progressive lens

near/center concentric or progressive lens

Low segment height for translation

High segment height for translation

Monofocal lens, concentric progressive, or concentric lens

Concentric near/center lens with large OZ, or distance/center lens with small OZ

Multifocal IOL

Multifocal IOLMultifocal IOL

12345

Bright light/ Distance dominant zoneLarge Near dominant zone

Low light/ Distance dominant zone

Distance zone

Near zone

Aspheric transition

REFRACTIVE MULTIFOCAL IOLs

Multiple focal points of a refractive MIOL

Silicone MIOLs

Array multifocal IOL (AMO)

First FDA approved foldable MIOL

Acrylic MIOLs

ReZoom multifocal IOL (AMO)

AcrySof ReSTOR lens (Alcon)

Tecnis multifocal IOL (AMO)

Multifocal IOLMultifocal IOL

The ARRAY®IOLRefractive Multifocal IOL Design

• Five concentric zones

• Each zone has a near or distance weighting

• Centre is distance weighted

3rd (distance dominant) ring enlarged and moved 3.4mm-3.9mm to 3.45mm-4.3mm

4th (near dominant) ring shifted from 3.9mm-4.6mm to 4.3mm-4.6mm (and thinned

out)

AMO ReZoom™

Good:• Provides excellent distance vision• Provides reasonable intermediate vision • Fewer halo and glare problems than the Array

Not-so-good:• Reading ability (near acuity) variable• Reading ability is pupil dependent• Less tolerable in myopes

DIFFRACTIVE MULTIFOCAL IOLs

Distance vision (white arrow) Near vision (blue arrow)


• Tecnis Multifocal IOLs (AMO)

– ZM900 (Silicone)

– ZA00 (Acrylic)

• Optic Diameter 6.0 mm

• Optic Type

– Modified prolate anterior surface

– Total diffractive posterior surface

• Diffractive Power +4.0 diopters of near addition (+3.0 Diopters at spectacle plane)

Tecnis ZM900 Tecnis ZA900


AMO Tecnis ZM9000 and Alcon ReSTOR

Alcon ReSTOR: Partial Optic Diffractive Apodized

• Only the central 3.6mm of optic contains diffractive rings with steps of certain height

• Now available in aspheric form• Step heights get progressively lower from centre to

periphery

AMO Tecnis™ ZM900 Multifocal and Alcon ReSTOR

Good:• Provide excellent distance and near vision• Fewer halo and glare problems than the Array• Most appreciated by hypermetropes• Well tolerated by (higher) myopesNot-so-good:• Intermediate vision suboptimal: problem for computer

users• Quality of vision not as acute as with a monofocal

(contrast sensitivity suffers)

REFRACTIVE MULTIFOCAL IOLS DIFFRACTIVE MULTIFOCAL IOLS

Excellent intermediate and distance vision Excellent reading vision and very good distance vision

Near vision fair but may not be sufficient to see very small print

Fair Intermediate vision

Patients who read for prolonged periods of time or in poor lighting may experience eye fatigue.

Patients who do lots of computer work may not accept it well

PUPIL DEPENDENT LESS DEPENDENT ON PUPIL

Refractive vs DiffractiveMULTIFOCAL IOLs

Disadvantages

• Reduction of contrast sensitivity

• Glare, haloes

• Less satisfactory visualization of fundus- difficulty in vitreo-retinal procedures

• Requires Visual-Cortical Neuro-adaptation

• Requires

• Accurate biometry

• Precise IOL implantation

• Astigmatic reduction

MULTIFOCAL IOLs

Monovision Vs multifocal IOLMonovision Vs multifocal IOL

Education

Monovision