MULTIFOCAL CONTACT LENSMUHAMMED FASAL. A

multifocal lenses are options for people who want to transition from bifocal or multifocal glasses to contact lenses. These types of contact lenses are great for people with active lifestyles who do not want to be chained to their reading glasses. There are different types of multifocal lenses available on the market that correct different types of vision disorders.

UNDERSTANDING MULTIFOCAL CONTACT LENS

Different Types ofMultifocal Contact Lenses.

•Soft Lenses:

Best for use on a part-time basis, soft lenses are a good choice because they are the easiest for the eye to adjust to.

•Gas Permeable Lenses:

Gas permeable lenses have been known to give better results, but they do require some adaptation for the wearer. Gas permeable (GP lenses) should be worn every day in order for your eyes to condition to them.

•Hybrid Multifocal Lens:

For those who want the best of both worlds, there is now a hybrid multifocal lens available that is soft around the peripheral with a gas permeable center – making this lens easier to wear with great vision results.

These are two of the different types of bifocal pattern lenses for bifocal and multifocal lenses.

Simultaneous Design

Alternating image design

•Simultaneous Design:

Puts the near and far portions of the lens in front of the pupil at the same time, which makes the brain have to determine which parts of the lens to use to get the best image resolution.

•Alternating image design:

This is the most similar to the bifocal and multifocal glasses currently available and uses the bottom portion of the lens for the near vision and the top portion of the lens for the distance vision. The two parts of the alternating lens is separated by an almost invisible line that your eye care provider uses to determine if the lens is fitting properly.

Translating

In this translating design the near power is on the bottom. The bottom edge is flattened to keep the lens from rotating on your eye when you blink.

ADVANTAGES

Sharp near / far visionWhen it works well , it is very successfulWorks better in RGP and less successful in SCL

DISADVANTAGES Takes longer in adaptationComfort is less due to thick designDependence on eye-lens relation ship

Blended / SIMULTANIUS VISION

This design is a little more uncommon, but provides the wearer with a more precise viewing experience. It typically places the distance and near prescriptions closer to the center of the eye, but corrects specific points of abnormally in the eyes, mimicking a natural viewing experience.

SIMULTANEOUS CONTACT LENS DESIGN

Diffractive

Aspheric

Translating

•Concentric Bifocal Pattern Lens:

This is the most commonly used lens for bifocal and multifocal lenses. With a concentric bifocal pattern contact lens, the near correction is located in a small circle at the center of the lens and is surrounded by a larger circle that contains the distance correction. This can be flip-flopped where the distance correction is in the center and the near correction is in the outer ring.

DIFFRACTIVE

This design is the most common design for multifocal contacts. It generally consists of a set of concentric circles that harbor different lens powers, often prescribed for different viewing distances

ASPHERIC DESIGNS

It formed with alteration of anterior and posterior curvature of the lens

ADVANTAGES No ghosting as in concentric designClarity of vision at all distancesSimplified fittingUsed mostly for office workers

DISADVANTAGES Pupil dependency

TWO TYPES OF ASPHERIC DESIGN ASPHERIC BACK SURFACE LENS DESIGN

ASPHERIC FRONT SURFACE LENS DESIGN

ASPHERIC BACK SURFACE LENS DESIGN

Fit well over aspheric corneaHas aspheric posterior curveIncreasing plus power peripherallyProvide central distance correction

ASPHERIC FRONT SURFACE LENS DESIGN

Aspheric anterior curveBack surface is sphericalIncreasing plus power centrallyProvide central near correction

Better visual acuity for the range of distances from near to far A less abrupt switch between prescriptions The ability to see in most conditions without extra eyewear

Advantages of multifocal

Multifocal contact lenses offer a lot of performance ability, but may also be:• More difficult to adjust to due to a different viewing experience• Accompanied by nighttime glare and hazy or shadowy vision during the adjustment period• More expensive because of the increased complexity in design

Drawbacks of multifocal

If multifocals don’t sound like they’re a good fit, there are a number of other options, including:

•Pairing reading glasses with normal contact lenses•Monovision contact lenses•Bifocal contact lenses•Surgical correction or lens implantation recommended by your doctor

Multifocal contact lens alternatives

MODIFIED MONOVISION This is a technique where one eye is

fitted with distance correction and the other eye is a bifocal lens

UNSUCCESSFUL CL FITTING High myopes Patients with busy schedules Dry eyes Flat corneas Laxity of lower lid High astigmatism

ANY DOUBTS …..?????

REFERENCE

CONTCT LENS DEPT ALSALAMADR AGARWALS CONTACT LENSES CONTACT LENS PRIMER ( MONICA CHAUDHRY )

1. WHEN SOFT CONTACT LENS STORED IN RGP SOLUTION , WHAT WILL HAPPEN ??

A- NOTHING WILL HAPPENB- LENS BECOME FLATTENC- LENS BECOME STEEPPEND- NON OF THE ABOVE

2. WHAT IS MODIFIED MONO VISION ??

3- WHAT ARE THE ADVANTAGES OF MULTIFOCAL CONTACT LENSES ?

4- WHAT IS UNIVERSAL BASE CURVE ??

Thank you…………….