PROFESSIONAL FITTING AND INFORMATION GUIDE

Transcription

1 CAUTION: PROFESSIONALFITTINGAND INFORMATIONGUIDE FLOSI(wilofoconA) RigidGasPermeableContactLensesforDailyWear ONSI 56(onsifoconA) RigidGasPermeableContactLensesforDailyWear TYRO 97(hofoconA) RigidGasPermeableContactLensesforDailyWear FORSPHERICAL,ASPHERIC,TORICANDBIFOCALCONTACTLENS Federal(USA)lawrestrictsthisdevicetosalebyorontheorderofalicensed practitioner.seepackageinsertforadditionalinformation.

2 TABLEOFCONTENTS Page Introduction 3 ProductDescriptions 3 LensParametersAvailable 3 Actions 4 Indications 4 Contraindications,Warnings,Precautions,andAdverseReactions4 SelectionofPatients 5 FittingProcedureOutline 6 Sphericallenses 6 Pre fittingexamination 6 InitialLensPowerSelection 6 InitialLensDiameterSelection 6 InitialLensBaseCurveSelection 7 InitialLensEvaluation 7 Toriclenses 8 Bifocallenses 12 AsphericMultifocallenses 14 Follow upcare 16 FittingGuideforMonovisionLenses 17 In OfficeCareofTrialLenses 21 RecommendedInitialWearingSchedule 21 ClinicalAssessment 22 CriteriaofaWell FittedLens 22 CharacteristicsofaTight(Steep)Lens 22 CharacteristicsofaLoose(Flat)Lens. 22 HandlingofLenses 22 PatientLensCareDirections 22 CareforaSticking(Non Moving)Lens 22 VertexDistanceandKeratometryConversion 23 ReportingofAdverseReactions 23 HowSupplied 23 PackageInsert 2

3 FLOSI(wilofoconA) ONSI 56(onsifoconA) TYRO 97(hofoconA) Rigid Gas Permeable Spherical, Aspheric, Toric and Bifocal Contact Lenses for Nearsightedness (Myopia), Farsightedness (Hyperopia), Astigmatic (Toric) Lenses to Correct Astigmatism.BifocalLensestoCorrectPresbyopia INTRODUCTION: TheseRigidGasPermeableSpherical,Aspheric,ToricandBifocalContactLensesaremadefrom fluorosiliconeacrylatepolymerswithawatercontentoflessthanonepercent. For a complete listing of available lens parameters, please refer to LENS PARAMETERS AVAILABLE. PRODUCTDESCRIPTIONS: FLOSI(wilofoconA),ONSI 56(onsifoconA),TYRO 97(hofoconA)RigidGasPermeable Spherical,Aspheric,ToricandBifocalContactLensesareavailableinsphericaldesignsinthe clearuntintedorblue,green,blue violetandgraytintedvarietiesandinbluewithuv blocker. Eachisashellofthefollowingdimensions. SphericalContactLens: HorizontalLensSize: 6.5mmto11.50mm BaseCurve: 6.50mmto9.50mm DistancePowers: Dto 20.00D CenterThickness: forlowminus0.05mmto0.30mm forplus 0.10mmto0.70mm AsphericLens Eccentricity 0to1.5 PeripheralCurves 0.1to1.0mm ToricLens Axis 1to180degreesin1degreesteps Cylinderpower 0.50 to4.00d TranslatingBifocalContactLens: HorizontalLensSize: 8.00mmto10.50mm BaseCurve: 6.50mmto8.50mm DistancePower: Dto 20.00D AddPower 1.00 to4.00d 3

4 Theserigidgaspermeablematerials,formakingcontactlensesareformulationsof trifluoroethylmethacrylatepolymerwithtris(trimethylsiloxy)methacryloxypropylsilane3 trimethoxysilylpropylmethacrylatemethacrylicacid1,3 bis(3 methacryloxypropyl)tetrakis (trimethylsiloxy)disiloxaneethyleneglycoldimethacrylate2 hydroxyethylmethacrylatenvinylpyrrolidone.thebluetintedlensescontaind&cgreenno.6;thegreenlensescontain D&CGreenNo6andCISolventYellow18;thegraylensescontainD&CGreenNo6,D&CViolet No.2,andCISolventYellow18;theblue UVlensescontainD&CGreenNo6andaUVabsorber, 2 (2' hydroxy 5' methacryloxyethylphenyl) 2H benzotriazole.thecolorantsareusedin quantitiesapprovedforuseincontactlensesandproportionsrequiredtoobtainthedesired color. ACTION: SEEPACKAGEINSERTFORINFORMATION INDICATIONS(USES): SEEPACKAGEINSERTFORINFORMATION CONTRAINDICATIONS(REASONSNOTTOUSE)WARNINGSANDADVERSEREACTIONS: SEEPACKAGEINSERTFORINFORMATION Caution: FLOSI (wilofocon A), ONSI 56 (onsifocon A), TYRO 97 (hofocon A) Rigid Gas Permeable Spherical, Aspheric, Toric and Bifocal Contact Lenses are shipped to the practitionernon sterile.cleanandconditionlensespriortouse. PRECAUTIONS: ClinicalstudieshavedemonstratedthatcontactlensesmanufacturedfromtheFLOSI(wilofocon A), ONSI 56 (onsifocon A), TYRO 97 (hofocon A) Rigid Gas Permeable materials are safe and effective for their intended use. However, due to the small number of patients enrolled in clinicalinvestigationoflenses,allrefractivepowers,designconfigurations,orlensparameters available in the lens material are not evaluated in significant numbers. Consequently, when selectinganappropriatelensdesignandparameters,theeyecarepractitionershouldconsider all characteristics of the lens that can affect lens performance and ocular health, including oxygenpermeability,wettability,centralandperipheralthickness,andopticzonediameter. Thepotentialimpactofthesefactorsonthepatient socularhealthshouldbecarefullyweighed againstthepatient'sneedforrefractivecorrection;therefore,thecontinuingocularhealthof thepatientandlensperformanceontheeyeshouldbecarefullymonitoredbytheprescribing eyecarepractitioner. 4

5 Patients who wear aspheric contact lenses to correct presbyopia may not achieve the best correctedvisualacuityforeitherfarornearvision.visualrequirementsvarywiththeindividual andshouldbeconsideredwhenselectingthemostappropriatetypeoflensforeachpatient. PleaserefertothePackageInsertforacompletelistofPrecautions SELECTIONOFPATIENTS: SPHERICALORTORICLENSES Patientswhorequireadailywearlensandarenot aphakicandhavenon diseasedeyes.the patientshouldhavearefractiveerrorwhichdoesnotexceed20.00dioptersofmyopiaor12.00 dioptersofhyperopia.thechoiceofsphereortoricisdependentontherefractiveerrortobe corrected.patientswithsmalleramountsofrefractiveorcornealastigmatism(lessthanabout 3.00D)canusuallybefitinasphericallens,whilepatientswithhigheramountsoftenrequirea toric lens to achieve acceptable acuity or fit. Patients with higher amounts of lenticular astigmatismmayalsorequireatoriclenstoachieveacceptableacuity. Patientsareselectedwhohaveademonstratedneedanddesireforarefractivecorrectionwith rigid gas permeable contact lenses and who do not have any of the contraindications for contactlensesdescribedinthepackageinsert. ASPHERICORBIFOCALLENSES Presbyopicpatientswhodesireimprovedvisionatfarandnearwithouttheuseofspectacles arecandidatesforeither: thetranslatingbifocal(addto+4.00d)or theasphericlens(addto1.25)withaneccentricity>0.4 Candidatesforanasphericlenswitheccentricity 0.4includepatientswho: Donothavepresbyopia,and Requirealensthatconformsmorecloselytotheircornealshapethanasphericallens. 5

6 FITTINGPROCEDURERIGIDGASPERMEABLESPHERICALCONTACTLENS FLOSI(wilofoconA),ONSI 56(onsifoconA),TYRO 97(hofoconA)RigidGasPermeableSpherical Contact Lenses may be fitted using the standard techniques for rigid gas permeable contact lenseswhetherthepatientisanewfit,formerhydrophiliccontactlenswearer,orformerrigid (orhardpmma)contactlenswearer.thechoiceoflensparametersisbasedsolelyontheneed toprovidethebestvisualacuityconsistentwithproperphysicalcomfort. FittingCriteria: Conventional rigid lens fitting techniques are used. This guide is only a general recommendation and the specification for an individual patient will depend on the eyecare practitioner'sprofessionaljudgment. 1.PrefittingExamination: Acompletedrefractionandvisualhealthexaminationshouldbeperformed. Apre fittingpatienthistoryandexaminationarenecessaryto: determine whether a patient is a suitable candidate for daily wear contact lenses (considerpatienthygieneandmentalandphysicalstate). makeocularmeasurementsforinitialcontactlensparameterselection collectandrecordbaselineclinicalinformationtowhichpost fittingexaminationresults canbecompared. 2.InitialLensPowerSelection: Standardproceduresfordeterminingpowerofrigidgaspermeablecontactlensesmaybeused, includingcompensationforvertexdistance. 3.InitialDiameterSelection: Usually lens diameters between 8.8 mm to 11.5 mm are used to maximize centering to the cornea and to minimize lens movement. Lens diameters outside this range are occasionally usedforsomeeyes.thisguideisonlyageneralrecommendationandthespecificationforan individualpatientwilldependontheeyecarepractitioner'sprofessionaljudgment. DeterminingLensDiameter: IfKis: 42.00andflatter...use9.8mmdiameter 42.25to use9.5mmdiameter 44.25andsteeper...use9.2mmdiameter 6

7 Lensdiameterisprimarilyafunctionofthebasecurvebutmaybeinfluencedbypower(plus lenses require a larger diameter to compensate for weight) and anatomical considerations (smallpalpebralopening,excessivelylargepupil,etc.) 4.InitialBaseCurveSelection: Thebasecurveisgenerallyfittedontheflattestkeratometricfinding(fittingon"K )butmay varyaccordingtothecornealastigmatismorotherindividualrequirements.thisguideisonlya general recommendation and the specification for an individual patient will depend on the eyecarepractitioner'sprofessionaljudgment. DeterminingLensBaseCurve: Thefollowingtablecanbeusedtoempiricallydeterminetheinitiallensparameters. Cylinder to.75 BC=.25steeper onk.25flatter 1.00to1.50 BC=.50steeper.25steeper onk >1.50 BC=.75steeper.50steeper.25steeper As can be seen from the above table, the base curve determination is a function of corneal cylinderandlensdiameter.thisguideisonlyageneralrecommendationandthespecification foranindividualpatientwilldependontheeyecarepractitioner'sprofessionaljudgment. 5.InitialLensEvaluation. Movement: Blinkinducedlensmovementshouldoptimallymovedownwardwiththelidmotionand thenupwardwiththelidmotion.duringtheinterblinkperiodthelensshouldhavelittle ornomotion. Positioning: The lens should position centrally or slightly superiorally to minimize both lens movement and lid sensation. Diagnostic lenses are essential in fitting patients whose cornealtopographyhasbeendistortedbypreviouscontactlenswear. 7

8 FITTINGPROCEDUREFORRIGIDGASPERMEABLETORICCONTACTLENS Theoverallandopticzonediametersarechosenusingthesamecriteriaaswithsphericallens designs. Generally, bitoric lens diameters are about 0.2 mm smaller than spherical lenses designedforintrapalpebralfitting.itisimportanttoavoidlidattachmentsincelidactionmay causethelenstorotatefromtheintendedaxis. There are two opposing considerations when selecting the toric posterior surface of a bitoric contactlensinordertoachievetheoptimumfit.thetoricsurfacemustconformcloseenough tothecornealcontourtominimizerotationofthclens.however,somedeviationfromperfect lens to corneaconformationisneededtocreatepumpingofthetearfluid. Thebasecurveintheflattermeridianshouldusuallybemade0.25Dflatter thanthecornea. The base curve in the steeper meridian should be 0.50 to 1.25 D flatter than the cornea dependingontheamountofcornealastigmatism.thisadditional"fitfactor"issummarizedin thefollowingtable: FITFACTOR CornealCyl(D) FlatMeridian SteepMeridian 2.00 OnK.50flatter flatter Mandell,R.C.,Moore,C.F.:ABitoricLensGuideThatReallyIsSimple.ContactLensSpectrum,November,1988, Thecalculationsofthetoriclenspowersaredividedforthetwoprincipalmeridiansandtreated asthoughtheyaretwoseparatelenses. The Mandell Moore Bitoric Lens Guide presents the steps to be taken in a bitoric lens calculationandasimpleformtobeusedinfollowingthesesteps.thismethodfollowsexactly thesamestepsasareusedtoarriveatasphericalcontactlensprescription. Example Readings: OD44.00@180/47.25@090 OS42.00@180/46.50@090 Refraction: OD x180 OS x180 8

9 At the top of the form, enter K readings for flat and steep meridians and the spectacle Rx in minuscylinderform. Line1 Line2 Line3 Line4 Line5 EntertheflatKreadingandthesteepKreadingwhereindicated. EnterthesphericalpowerofthespectacleRx.Thenaddthesphereandcylinder power algebraically and record this value in minus cylinder form where indicated. If either power value is greater than 4.00 D, convert the spectacle Rx to the cornealplaneusingthevertexdistancecorrectiontableontheform. Addthe"fitfactor."Thisadjustmentpromotesanalignmentfit.First,enterthe fitfactorfortheflatmeridian,whichwillalwaysbe0.25dandhaveaminussign. Next, enter the same value under sphere power, which will have a plus sign. Repeat the same process by finding the fit factor for the steeper meridian and enterthevalues. The base curve Rx is calculated by adding the values in line one and four. The powerisdeterminedbyaddinglinesthreeandfour. Aswithsphericallenses,centerthicknessisafunctionoflensdesign.Withbitoriclenses,the centerthicknessisbasedfromtheleastminusorgreatestpluspower. Intermediate and peripheral curves can be generated in either a spherical or toric design. Sphericalperipheralcurveswillresultinanovalopticzone.Reviewthesphericallenssection foractualparameterdetermination. 9

10 RightEye SpectacleRx(minuscylinderform) x FlattestK SpherePower SteepestK Sph+cylpwr 1.EnterK XXXXXXX XXXXXXXX 2.EnterSpectaclePower 3.VertexCorrection 4.FitFactor ( ) (+) ( ) (+) AddLines 1&4 3&4 1&4 3&4 5.FinalCLRx BaseCurve Power BaseCurve Power LeftEye SpectacleRx(minuscylinderform) x FlattestK SpherePower SteepestK Sph+cylpwr 1.EnterK XXXXXXX XXXXXXXX 2.EnterSpectaclePower 3.VertexCorrection 4.FitFactor ( ) (+) ( ) (+) AddLines 1&4 3&4 1&4 3&4 5.FinalCLRx BaseCurve Power BaseCurve Power Ifthespectaclelenspowerislessthan4.00diopters,thenline3=line2.Otherwise:forminus powerspectaclelenses,findthepowerintheleftsideofthecolumnandconverttothepower intherightsideofthecolumn,butretaintheminussign.forpluspowerspectaclelenses,find thepowerintherightsideofthecolumn,andconverttothepowerintheleftside,butretain theplussign. 10

11 VERTEXDISTANCECORRECTION Ifthespectaclelenspowerislessthan4.00diopters,thenline3=line2.Otherwise:forminus powerspectaclelenses,findthepowerintheleftsideofthecolumnandconverttothepower intherightsideofthecolumn,butretaintheminussign.forpluspowerspectaclelenses,find thepowerintherightsideofthecolumn,andconverttothepowerintheleftside,butretain theplussign. FITFACTOR CORNEALCYL,D FLATMERIDIAN STEEPMERIDIAN 2 ONK.50FLATTER FLATTER

12 FITTINGPROCEDURERIGIDGASPERMEABLETRANSLATINGBIFOCALCONTACTLENS Selectapatientwith+4.00addorlowerinterestedinfull timewear. Interview patient regarding expected lens use, vocation and hobbies, previous type of lenswear,etc. Thesamepre fittingcriteriaapplyforbothsphericandbifocalrgpfittings.pleaserefer tothesphericallensfittingguide. Initiallensdiameterselectionisbasedonthesamefactorsasforasphericallens.Refertotrial lenssizechartinthesphericalfittingguide. Using the amount of corneal cylinder, the base curve may be determined by the following table: CornealCylinder,D BaseCurve DflattertoOnK OnKto0.25Dsteeper to0.75Dsteeper > to1.25Dsteeper Selectthepropertriallensandplaceitonthepatient'scornea.Waitapproximately10 minutesoruntiltearingsubsidesandcheckforlenspositioningandmovement.ideally, thelenswillrideupwiththeblinkandthenquicklydroptoapositionwhichisnearthe centerofthecornea.centeringisimportantwhenfittingbifocallenses.ifthetriallens does not center, you may find an unanticipated amount of residual astigmatism. To correctthis,followthestepsintheproblem solvingsection. Lenspowers(farcenter,addperiphery)maybedeterminedbyconventional methods. Center thickness is a function of lens design. Refer to the spherical fitting guide for furtherdetails Lookforcentraltosuperior centrallensposition.thisprovidesforadequatedistance vision,whilereducingedgeglareandflareindimlightoratnight.onsi 56(onsifocon A) RIGID GAS PERMEABLE TRANSLATING BIFOCAL CONTACT LENSES provide both far andnearvision,meaningthatthelensmusttranslateeasilyacrossthecornealsurface as the patient looks from distance to reading tasks. Proper base curve selection will usuallyensurethatthelenswillmoveeasilyalongtheverticalcornealmeridian. Evaluatefluoresceinpatternandlenstranslation. 12

13 EvaluationofLensPositioning Preferred Fit Alignmentfitwithcentraltosuperior/centralpositioning 0.1mm Steeper Fit Increasedapicalclearance,combinedwithmid peripheralbearing 0.1mm Flatter Fit Increasedcentralbearingwithlossoflensstability EvaluationofLensPositionandMovement Ideally,thelensshouldpositioninthecentraltosuperior/centralposition,withthelens opticssituatedoverthepupil. Typically, the fluorescein pattern will demonstrate "alignment" along the flattest cornealmeridian. During downward gaze the lens should easily translate superiorly providing maximum readingvision. NOTE:Ifanalignmentfittingrelationshipcombinedwithacceptableverticaltranslation cannot be achieved with the initial diagnostic lens, simply choose the next steeper or flatterbasecurveandevaluate. 13

14 FITTINGPROCEDUREFORRIGIDGASPERMEABLEASPHERICCONTACTLENS The same pre fitting criteria apply for both spheric and aspheric RGP fittings. Please refer to thesphericallensfittingguide. Initiallensdiameterselectionisbasedonthesamefactorsasforasphericallens.Refertotrial lenssizechartinthesphericalfittingguide.inaddition,owingtotheasphericlensdesign,the fitterwillnotneedtodetermineperipheralcurves. Using the amount of corneal cylinder, the base curve may be determined by the following table: CornealCylinder,D BaseCurve DflattertoOnK OnKto0.25Dsteeper to0.75Dsteeper > to1.25Dsteeper Selectthepropertriallensandplaceitonthepatient'scornea.Waitapproximately10minutes or until tearing subsides and check for lens positioning and movement. Ideally, the lens will ride up with the blink and then quickly drop to a position which is near the center of the cornea. Centering is important when fitting aspheric lenses. If the trial lens does not center, youmayfindanunanticipatedamountofresidualastigmatism.tocorrectthis,followthesteps intheproblem solvingsection. Lens power is best determined by over refraction with a trial lens in place. Perform the calculationstepsasyouwouldwithasphericallens.refertothesphericallens fittingguidefor details. Center thickness is a function of lens design. Refer to the spherical fitting guide for further details. Note:Abifocaleffectshouldbeexpectedforeccentricities>0.4.Whenfittingtheasphericlens forpresbyopia,practitionersshouldselectonlypatientswhoneedanaddof+1.25orless. PatientEducation All patients do not function equally well with aspheric multifocal correction. Patients maynotperformaswellforcertaintaskswiththiscorrectionastheyhavewithbifocal readingglasses.eachpatientshouldunderstandthatasphericmultifocallenses,aswell asotherpresbyopiccontactlenses,orotheralternative,cancreateavisioncompromise thatmayreducevisualacuityanddepthperceptionfordistanceandneartasks.during 14

15 thefittingprocessitisnecessaryforthepatienttorealizethedisadvantagesofthelack ofclearnearvisioninstraightaheadgazethatasphericmultifocallensesprovide. Adaptation Visually demanding situations should be avoided during the initial wearing period. A patient may at first experience some mild blurred vision, dizziness, headaches, and a feeling of slight imbalance. You should explain the adaptational symptoms to the patient. These symptoms may last for a brief minute or for several weeks. The longer thesesymptomspersist,thepoorertheprognosisforsuccessfuladaptation. Tohelpintheadaptationprocessthepatientcanbeadvisedtofirstusethelensesina comfortablefamiliarenvironmentsuchasinthehome. Somepatientsfeelthatautomobiledrivingperformancemaynotbeoptimalduringthe adaptation process. This is particularly true when driving at night. Before driving a motor vehicle, it may be recommended that the patient be a passenger first to make surethattheirvisionissatisfactoryforoperatinganautomobile.duringthefirstseveral weeks of wear (when adaptation is occurring), it may be advisable for the patient to drive only during optimal driving conditions. After adaptation and success with these activities,thepatientshouldbeabletodriveunderotherconditionswithcaution. OtherSuggestions The success of the aspheric multifocal technique may be further improved by having yourpatientfollowthesuggestionsbelow. Having supplemental spectacles to wear over the aspheric contact lenses for specific visual tasks may improve the success of aspheric correction. This is particularly applicable for those patients who cannot meet state licensing requirements with a asphericcorrection. Makeuseofproperilluminationwhencarryingoutvisualtasks. Success in fitting aspheric multifocal lenses can be improved by the following suggestions. Refine the lens powers if there is trouble with adaptation. Accurate lens power is criticalforpresbyopicpatients. * The decision to fit a patient with an aspheric multifocal correction is most appropriately left to the eyecare practitioner in conjunction with the patient aftercarefullyconsideringthepatient'sneeds. 15

16 * AllpatientsshouldbesuppliedwithacopyoftheWearer sinstructionsforthe FLOSI (wilofocon A), ONSI 56 (onsifocon A), TYRO 97 (hofocon A) Rigid Gas PermeableSpherical,Aspheric,ToricandBifocalContactLenses 6.FOLLOWUPCARE: a. Follow upexaminations,asrecommendedbytheeyecarepractitioner,arenecessaryto ensurecontinuedsuccessfulcontactlenswear.follow upexaminationsshouldinclude an evaluation of lens movement, centration, comfort and fluorescein pattern. Lens movementwilldecreaseastearvolumeisdiminishingduringadaptation.thepatient should also begin to feel more comfortable. An assessment of vision and eye health, includinginspectionofthecorneaforedemaand/orstaining,shouldbeperformed. b. Prior to a follow up examination, the contact lenses should be worn for at least 4 contiguoushoursandthepatientshouldbeaskedtoidentifyanyproblemswhichmight beoccurringrelatedtocontactlenswear. c. d. Withlensesinplaceontheeyes,evaluatefittingperformancetoassurethatCRITERIA OFAWELLFITTEDLENScontinuetobesatisfied.Examinethelensescloselyforsurface depositionand/ordamage. Afterthelensremoval,conductathoroughbiomicroscopyexamination. 1. The presence of vertical corneal striae in the posterior central cornea and/or cornealneovascularizationisindicativeofexcessivecornealedema. 2. The presence of corneal staining and/ or limbal conjunctival hyperemia can be indicativeofanuncleanlens,areactiontosolutionpreservatives,excessivelens wear,and/orapoorlyfittedlens. If any of the above observations are judged abnormal, various professional judgments are necessarytoalleviatetheproblemandrestoretheeyetooptimalconditions.ifthecriteria OFAWELLFITTEDLENSarenotsatisfiedduringanyfollow upexamination,thepatientshould bere fittedwithamoreappropriatelens. 16

17 MONOVISIONFITTINGGUIDELINES: 1. PatientSelection A. MonovisionNeedsAssessment Foragoodprognosisthepatientshouldhaveadequatelycorrecteddistanceand near visual acuity in each eye. The amblyopic patient or the patient with significant residual astigmatism(greater than 1.00 diopter) in one eye may not beagoodcandidateformonovisionwiththeonsi 56(onsifoconA)RigidGas PermeableContactLens. Occupational and environmental visual demands should be considered. If the patient requires critical vision (visual acuity and stereopsis) it should be determined by trial whether this patient can function adequately with monovision.monovisioncontactlenswearmaynotbeoptimalforsuchactivities as: (1) visually demanding situations such as operating potentially dangerous machineryorperformingotherpotentiallyhazardousactivities;and (2) drivingautomobiles(e.g.,drivingatnight).patientswhocannotpasstheir statedriverslicenserequirementswithmonovisioncorrectionshouldbe advisedtonotdrivewiththiscorrection,ormayrequirethatadditional over correctionbeprescribed. B. PatientEducation All patients do not function equally well with monovision correction. Patients maynotperformaswellforcertaintaskswiththiscorrectionastheyhavewith bifocalreadingglasses.eachpatientshouldunderstandthatmonovision,aswell as other presbyopic contact lenses, or other alternative, can create a vision compromise that may reduce visual acuity and depth perception for distance andneartasks.duringthefittingprocessitisnecessaryforthepatienttorealize the disadvantages and advantages of clear near vision in straight ahead and upwardgazethatmonovisioncontactlensesprovide. 2. EyeSelection Generally,thenon dominanteyeiscorrectedfornearvision.thefollowingtestforeye dominancecanbeused. A. OcularPerformanceDeterminationMethods 17

18 Method1 Determinewhicheyeisthe"sighteye."Havethepatientpointtoan object at the far end of the room Cover one eye. If the patient is still pointing directlyattheobject,theeyeisbeingusedisthedominant(sighting)eye. Method 2 Determine which eye will accept the added power with the least reductioninvision.placeatrialspectaclenearaddlensinfrontofoneeyeand thentheotherwhilethedistancerefractiveerrorcorrectionisinplaceforboth eyes.determinewhetherthepatientfunctionsbestwiththenearaddlensover theerightorlefteye. B. RefractiveErrorMethod Foranisometropiccorrections,itisgenerallybesttofitthemorehyperopic(less myopic)eyefordistanceandthemoremyopic(lesshyperopic)eyefornear. C. VisualDemandsMethod Considerthepatient'soccupationduringtheeyeselectionprocesstodetermine thecriticalvisionrequirements.ifapatient'sgazeforneartasksisusuallyinone directioncorrecttheeyeonthatsidefornear. Example: Asecretarywhoplacescopytotheleftsideofthedeskwillusuallyfunctionbest withthenearlensontheelefteye. 3. SpecialFittingConsiderations UnilateralLensCorrection Therearecircumstanceswhereonlyonecontactlensisrequired.Asanexample, an emmetropia patient would only require a near lens while a bilateral myope mayrequireonlyadistancelens. Example: Apresbyopicemmetropiapatientwhorequiresa+1.75diopteraddwouldhave a+1.75lensontheneareyeandtheothereyeleftwithoutalens. 18

19 Apresbyopicpatientrequiringa+1.50diopteraddwhois 2.50dioptersmyopic intherighteyeand 1.50dioptersmyopicinthelefteyemayhavetherighteye correctedfordistanceandtheleftuncorrectedfornear. 4. NearAddDetermination Alwaysprescribethelenspowerfortheneareyethatprovidesoptimalnearacuityat themidpointofthepatient'shabitualreadingdistance.however,whenmorethanone powerprovidesoptimalreadingperformance,prescribetheleastplus(mostminus)of thepowers. 5. TrialLensFitting A trial fitting is performed in the office to allow the patient to experience monovision correction.lensesarefitaccordingtothedirectionsinthegeneralfittingguidelinesand basecurveselectiondescribedearlierintheguide. Casehistoryandstandardclinicalevaluationprocedureshouldbeusedtodeterminethe prognosis.determinewhicheyeistobecorrectedfordistanceandwhicheyeistobe correctedfornear.nextdeterminethenearadd.withtriallensesoftheproperpower inplaceobservethereactiontothismodeofcorrection. Immediatelyafterthecorrectpowerlensesareinplace,walkacrosstheroomandhave the patient look at you. Assess the patient's reaction to distance vision under these circumstances.thenhavethepatientlookatfamiliarnearobjectssuchasawatchface or fingernails. Again assess the reaction. As the patient continues to look around the roomatbothnearanddistanceobjects,observethereactions.onlyafterthesevision tasks are completed should the patient be asked to read print. evaluate the patient's reactiontolargeprint(e.g.typewrittencopy)atfirstandthengraduatetonewsprint andfinallysmallertypesizes. After the patient's performance under the above conditions are completed, tests of visualacuityandreadingabilityunderconditionsofmoderatelydimilluminationshould beattempted. An initial unfavorable response in the office, while indicative of a guarded prognosis, should not immediately rule out a more extensive trial under the usual conditions in whichapatientfunctions. 19

20 6. Adaptation Visually demanding situations should be avoided during the initial wearing period. A patient may at first experience some mild blurred vision, dizziness, headaches, and a feeling of slight imbalance. You should explain the adaptational symptoms to the patient. These symptoms may last for a brief minute or for several weeks. The longer thesesymptomspersist,thepoorertheprognosisforsuccessfuladaptation. Tohelpintheadaptationprocessthepatientcanbeadvisedtofirstusethelensesina comfortablefamiliarenvironmentsuchasinthehome. Somepatientsfeelthatautomobiledrivingperformancemaynotbeoptimalduringthe adaptation process. This is particularly true when driving at night. Before driving a motor vehicle, it may be recommended that the patient be a passenger first to make surethattheirvisionissatisfactoryforoperatinganautomobile.duringthefirstseveral weeks of wear (when adaptation is occurring), it may be advisable for the patient to drive only during optimal driving conditions. After adaptation and success with these activities,thepatientshouldbeabletodriveunderotherconditionswithcaution. 7. OtherSuggestions The success of the monovision technique may be further improved by having your patientfollowthesuggestionsbelow. Having a third contact lens (distance power) to use when critical distance viewingisneeded. Having a third contact lens (near power) to use when critical near viewing is needed. Havingsupplementalspectaclestowearoverthemonovisioncontactlensesfor specific visual tasks may improve the success of monovision correction. This is particularly applicable for those patients who cannot meet state licensing requirementswithamonovisioncorrection. Makeuseofproperilluminationwhencarryingoutvisualtasks. Successinfittingmonovisioncanbeimprovedbythefollowingsuggestions. Reversethedistanceandneareyesifapatientishavingtroubleadapting. Refinethelenspowersifthereistroublewithadaptation.Accuratelenspower iscriticalforpresbyopicpatients. 20

21 Emphasize the benefits of the clear near vision in straight ahead and upward gazewithmonovision. * Thedecisiontofitapatientwithamonovisioncorrectionismostappropriately lefttotheeyecarepractitionerinconjunctionwiththepatientaftercarefully consideringthepatient'sneeds. * AllpatientsshouldbesuppliedwithacopyoftheWearer sinstructionsforthe FLOSI (wilofocon A), ONSI 56 (onsifocon A), TYRO 97 (hofocon A) Rigid Gas PermeableSpherical,Aspheric,ToricandBifocalContactLenses INOFFICECAREOFTRIALLENSES: Eyecare practitioners should educate contact lens technicians concerning proper care of trial lenses. RECOMMENDEDINITIALWEARINGSCHEDULE Althoughmanypractitionershavedevelopedtheirowninitialwearingschedules,thefollowing sequenceisrecommendedasaguideline.patientsshouldbecautionedtocarefullyfollowthe wearingschedulerecommendedbytheeyecarepractitionerregardlessofhowcomfortablethe lensesfeel. DailyWear Maximumwearingtime: Day WearingTime(Hours) andafter Allhoursawake 21

22 CLINICALASSESSMENT: 1. CriteriaofaWell FittedLens Thelensshouldideallymovefreelywiththeblinkanddropquicklytoaposition nearthecenterofthecornea.itisespeciallyfavorableifthelensridesslightly undertheupperlidsincethatwillreducelensedgesensationandmakethelens morecomfortable.thelensshouldnotrideexceptionallyhighsothatexcessive lidpressureisexertedonthesuperiorlensmargin.overanextendedwearing period, this inevitably leads to structural changes in the superior corneal epithelium. The lens should center well and move adequately following the blink. 2. CharacteristicsofaTight(Steep)Lens Alensthatistootightwillshowreducedmovementuponblinking.Thelenswill becenteredordecenteredinferiorlyandexhibitlittleornomovement.bubbles maybedetectedbehindthelens. 3. CharacteristicsofaLoose(Flat)Lens Alensthatistooloosewillmoveexcessivelyonthecorneafollowingeachblink. The lens may ride in either a position that is too high or too low or in an eccentricposition.alooselensisusuallyuncomfortableforthepatient. HANDLINGOFLENSES: Standardproceduresforrigidgaspermeablelensesmaybeused. Caution: FLOSI (wilofocon A), ONSI 56 (onsifocon A), TYRO 97 (hofocon A) Rigid Gas PermeableSpherical,Aspheric,ToricandBifocalContactLensareshippedtothepractitioner non sterile.cleanandconditionlensespriortouse. PATIENTLENSCAREDIRECTIONS: Pleaseseepackageinsert. CAREFORASTICKING(NONMOVING)LENS: PleaseSeePackageInsert 22

23 VERTEXDISTANCEANDKERATOMETRYCONVERSIONCHARTS Standardchartsmaybeused. REPORTINGOFADVERSEREACTIONS All serious adverse experiences and adverse reactions observed in patients wearingorexperiencedwiththelensesshouldbereportedto: TheLagadoCorporation 2890SouthTejonBoulevard Englewood,CO HOWSUPPLIED Each lens is supplied non sterile in a plastic lens storage case containing one or two lenses. The container is marked with the patient name, base curve, distance power, diameter,centerthickness,color,andlotnumber. 23