TORIC SOFT CONTACT TORIC SOFT CONTACT LENSES FOR ASTIGMATISMLENSES FOR ASTIGMATISM

Author : Irina Velcea, MD Author : Irina Velcea, MD BucharestBucharest

IntroductionIntroduction

Studies show that about 15% of adult Studies show that about 15% of adult population have astigmatism > 1 D and only population have astigmatism > 1 D and only 2% have astigmatism >3 D while the 2% have astigmatism >3 D while the incidence of astigmatism in childhood is incidence of astigmatism in childhood is greater.greater.

Almost all of them can have an alternative to Almost all of them can have an alternative to the glasses : toric soft contact lenses.the glasses : toric soft contact lenses.

ObjectiveObjective

- to present the experience in prescribing toric - to present the experience in prescribing toric soft contact lenses in our clinic ;soft contact lenses in our clinic ;

- to realize a comparative study between two - to realize a comparative study between two soft toric contact lenses .soft toric contact lenses .

Material and methodsMaterial and methods

- we considered a group of 35 new cases who we considered a group of 35 new cases who were fitted between September 2006 – were fitted between September 2006 – August 2007;August 2007;

- the toric lenses used were : Pure Vision - the toric lenses used were : Pure Vision Toric and Soflens 66 Toric Toric and Soflens 66 Toric

Lens presentation :Lens presentation :

- 2.75 D  

- 0.75 D, -1.25 D, -1.75 D, - 2.25 D- 0.75 D, -1.25 D, -1.75 D, -2.25 DCylinders

( 0.50 D step ) ( 0.50 D step)

- 6.50 D la - 9.00 D- 6.50 D la - 9.00 D

( 0.25 D step )( 0.25 D step )

+ 6.00 D la - 6.00 D+ 6.00 D - 6.00 D

Sferical Diopters

14.5 mm14 mmDiameter

8.5 mm8.7 mmBC

Dk/t1691

 

66.00%36.00%Water content

hidrogel (Alphafilcon A)silicone-hydrogel (Balafilcon A)

SofLens Toric PureVision ToricMaterial

The trial group – distribution by The trial group – distribution by gendergender

The trial group – distribution by ageThe trial group – distribution by age

The trial group – distribution by The trial group – distribution by refractive errorsrefractive errors

The trial group – distribution by the The trial group – distribution by the amount of astigmatismamount of astigmatism

The trial group – distribution by The trial group – distribution by associated ocular diseasesassociated ocular diseases

The trial group – distribution by lens The trial group – distribution by lens typetype

The trial group – distribution by lens The trial group – distribution by lens type / amount of astigmatismtype / amount of astigmatism

ELECTION CRITERIAELECTION CRITERIA

Corneal parameters Corneal parameters Patient’s agePatient’s age The size of astigmatismThe size of astigmatism The comfort in first few minutesThe comfort in first few minutes The lens behavior on the eyeThe lens behavior on the eye Patient’s compliance after 2 weeks of Patient’s compliance after 2 weeks of

wearingwearing Costs and presentationCosts and presentation

The election criteria – corneal The election criteria – corneal parametersparameters

BCBC Corneal diametersCorneal diameters BUTBUT Schirmer testSchirmer test

The election criteria – the comfort in The election criteria – the comfort in first few minutesfirst few minutes

- to judge the subjective reaction to the lens in - to judge the subjective reaction to the lens in the first 15 – 30 minutesthe first 15 – 30 minutes

No significant difference in preference for comfort at insertion

81.7

85

50 60 70 80 90 100

PVT 66T

Comfort Ratings & Preference

Comfort

The election criteria – the lens The election criteria – the lens behavior on the eyebehavior on the eye

The lens on the The lens on the corneacornea

- central location- central location

- motility- motility

- rotation- rotation

- local irritation- local irritation

The election criteria – patient’s The election criteria – patient’s compliance after 2 weeks of wearingcompliance after 2 weeks of wearing

Visual acuity evaluationVisual acuity evaluation Lens fitting evaluation Lens fitting evaluation Lens exam to observe depositsLens exam to observe deposits Corneal and eyelid slit-lamp examinationCorneal and eyelid slit-lamp examination

RESULTSRESULTS

Rotational stability : equal or even greater with Rotational stability : equal or even greater with Pure Vision Toric than with Soflens 66 Toric ;Pure Vision Toric than with Soflens 66 Toric ;

Visual acuity : equal or even greater with Pure Visual acuity : equal or even greater with Pure Vision Toric than with Soflens 66 Toric ;Vision Toric than with Soflens 66 Toric ;

The initial comfort was greater with Soflens 66 The initial comfort was greater with Soflens 66 Toric, but equal after 2 weeks ;Toric, but equal after 2 weeks ;

The physiological response to extended wearing The physiological response to extended wearing was better with Pure Vision Toric .was better with Pure Vision Toric .

CONCLUSIONSCONCLUSIONS

The introduction of toric silicone hydrogel The introduction of toric silicone hydrogel contact lenses provide the practitioners the contact lenses provide the practitioners the opportunity to change conventional toric opportunity to change conventional toric lenses to a newer material / design lenses to a newer material / design technology. Their high levels of oxygen technology. Their high levels of oxygen transmissibility ensure their future.transmissibility ensure their future.

The toric hydrogel lenses are still an The toric hydrogel lenses are still an important option in high astigmatism important option in high astigmatism correction. correction.

CONCLUSIONSCONCLUSIONS

Lens design and material properties can Lens design and material properties can influence fitting characteristics and vision.influence fitting characteristics and vision.

Clinicians should remember some of the Clinicians should remember some of the differences between materials in order to differences between materials in order to manage their patients appropriately.manage their patients appropriately.