Cataract 2

7/28/2019 Cataract 2

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GLOBALTHERAPEUTICSOLUTIONSINOPHTHALMOLOGY 2

Besidesage,thereareotherriskfactors.Forinstance,atraumaticcataractmayresultfromaneye

trauma7.Thedelaybetweentheinitialtraumaandtheonsetofsymptomsmayvaryfromafewdays

toseveralyears.

Certainmedical interventionscancause lenscloudiness, inthiscasecalledaniatrogeniccataract.

Longtermtreatmentwithcorticosteroidsmay leadtoacataract8.Certainsurgical interventionson

theeye,forexampleintraocularimplantsorvitrectomies,mayalsocauselenscloudiness8.Finally,

cataractscanalsobeduetoXrayexposure,forinstanceinthecaseofcancerradiotherapy8.

Insomecases,thecataract issecondarytoothermedicaldiseases,suchasdiabetes9,orothereye

diseaseslikeseveremyopia,uveitis,orglaucoma8.

Smokingandalcoholconsumptionarealsocataractriskfactors7.Notethatcataractsmayalreadybe

presentatbirthwhenthemothercontractedmeaslesduringpregnancy.Thiscongenitalcataract is

veryrare,

and

concerns

fewer

than

eight

births

per

100,000.10

__________________________

SymptomsThecloudinessofthecrystallinelensusuallydevelopsslowlyandprogressively.Itveryoftenaffects

botheyes,butatvaryingdegrees11.Dependingonwhichregionofthecrystallinelensisaffected,the

cataract

can

be

associated

with

other

symptoms.

Asthecloudinessofthecrystallinelensprogresses,lightraysarelessabletopenetratethelensand

reach the retina,andvisionbecomesobscured.Patientsperceiveakindofa fogbeforetheireyes

and headlights may appear too bright. Also, halos may appear around lights. All this may be

particularlydisturbingduringthenight,duetotheheadlightsofothercars,oronverysunnydays7.

Colour visionmay be altered,with colours appearing faded.7 Another, less common symptom is

doublevision,calledmonoculardiplopia.Eventually,thisconditioncausesaprogressiveandpainless

decreaseinvisualacuity7.Furthermore,infarsightedpatients,myopiamaydeveloptosuchadegree

thattheirclosevisionactuallyimproves7.

If notice these symptoms, you should consult your ophthalmologist quickly, as a thorough

examinationofyoureyesisrequired.

__________________________

DiagnosisThefirststepisadetaileddiscussionwithyourophthalmologist,whowillaskyouprecisequestions

aboutyoursymptoms.Hewillthenmeasureyourvisualacuityforcloseanddistancevisionbyasking

youto

read

letters

of

different

size

on

an

illuminated

display.


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However, themost important examination is performedwith an instrument called a slit lamp. It

allowsyourdoctortoseewithgreatprecisionwhetheryourlensiscloudedandifyousufferfroma

cataract. If this is the case, the slit lampexaminationallowshim todetermine theexact location,

characteristics,anddimensionsofthecloudiness.

Inordertoexcludeallothereyedisorders,yourophthalmologistmayalsoperformcomplementary

examinations. A measurement of intraocular pressure allows him to exclude glaucoma, and an

examinationof thebackofyoureyepermitshim to ruleoutanyafflictionof the retinaoroptical

nerve.

__________________________

ExaminationsInordertodeterminewhetheryousufferfromacataract,theophthalmologistperformsaslitlamp

examinationofyoureye.

Composedofamobilelightsourceandadoublemicroscope,thisinstrumentallowsthe

ophthalmologisttomagnifytheanteriorpartoftheeye,whichconsistsoftheanteriorchamber,the

cornea,theiris,thepupil,thevitreousbody,andthecrystallinelens.

Thisexamdoesnottakealongtimeandispainless.Sometimes,inordertodilateyourpupilsand

facilitate

the

examination,

your

ophthalmologist

may

apply

eye

drops

before

the

examination.

You

willsitinfrontoftheapparatuswithyourchinrestingonachinrestandyourforeheadpressedto

thedevice.Ontheothersideoftheapparatus,yourophthalmologistwillexamineoneeyeafterthe

otherwithabrightlight.

__________________________

ProgressionandcomplicationsThe

cataract

always

causes

an

increasing

cloudiness

of

the

crystalline

lens,

though

the

speed

at

which

thecloudinessdevelopsisvariable.Intheabsenceoftreatment,visualacuitydeterioratesin60%to

70%ofpatientswithin2years.2Thisdeteriorationseemstobemorerapidinpatientssufferingfrom

cloudinesslocatedontheposteriorlenscapsuleandinpatientsaffectedbyjuvenilediabetes2.With

time,cataractsmaycloudthecrystallinelenscompletelyandcauseblindness6.Othercomplications

maybeobservedifthecataractisnotappropriatelytreated.Inrarecases,asharpincreaseinthe

crystallinelensvolumemayprovokeanincreaseinintraocularpressureand,byextension,acute

glaucoma7.Pleasenotethatinindustrializednations,cataractsarewelltreatedwithsurgery,

permittingustoavoidthesecomplications.InFrance,cataractsurgeryisthemostfrequentformof

surgicalintervention,andisperformed500,000timeseachyear.12

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TreatmentToday,

the

only

curative

treatment

is

surgery.

It

consists

of

replacing

the

crystalline

lens

with

an

intraocularimplantinordertocompensateforitsdecreasingrefractorypower.

IndicationsIngeneral,cataracttreatmentisnotanemergencyoperation.Thedecisiontooperatewilldependon

theseriousnessofyourcomplaintsandtheextentofyourvisionloss.Yourophthalmologistwillalso

takeintoaccountyoursocioprofessionalbackgroundandthepresenceofotherconcomitantfactors

whichaffectyourvisualacuity.Thereisnovisualacuitythresholdwhichclearlyindicatessurgery,but

generallyasurgicalinterventionisproposedwhenyourvisualacuityislessthan4to5/10ths.13

TechniquesThree

different

techniques

may

be

employed

to

extract

the

cataract:

Intracapsularextractioninvolvesthecreationofawideopeninginthecorneainordertoremovetheentirecrystallinelenswithaninstrumentcalledacryode.Thereafter,anintraocularimplantisput

intoplace.Today,thistechniqueisnolongerused.

Extracapsularextractioninvolvesalongerincisiononthesideofthecornea,andremovesthecrystallinecoreandcortexwithaspatulashapedtool,whileleavingthecapsuleinplace.Following

this,thesurgeonintroducestheintraocularimplantintothecapsule.Thistechniqueisnowusedless

andlessfrequently,asithasbeenreplacedbythefollowingprocedure,butitisstillemployedwhen

thecloudinessisverydense.

Phacoemulsificationisthetechniqueofchoiceinindustrializedcountriesforseveralreasons:itis

effective,successisrelativelypositive,and,asitinvolvesonlyaverysmallincision,recoveryofvision

isveryquick12.Duringphacoemulsification,asmallincisionismadeonthesideofthecornea,anda

tinyprobeisinsertedintoyoureye.ThisdeviceemitsUltrasoundwavesthatsoftenandbreakup

yourlens,allowingittoberemovedbysuctionwithoutdisplacingthelenscapsule.Anintraocular

implantisthenputintoplace.

ResultsAsthesurgicalinterventionismostoftenconductedunderlocalanaesthesia

12,itcanbeperformed

asanoutpatientprocedure.Note,however,thatyouwillnotbeallowedtodriveonthedayofthe

procedure,soyoushouldmakeappropriateprovisions.

Thedayafterthesurgery,youwillhavetoreturntoseeyoursurgeon,whowillexaminethestateof

youreye.Regularvisitsonascheduledeterminedbyyourophthalmologistwillbenecessary

thereafteraspartofalongtermfollowup.

Ingeneral,resultsareverypositive.Inthemajorityofcases,visionrecoverswithin4daysofthe

operation12

andmorethan90%ofpatientsachievevisualacuitygreaterthanorequalto5/10ths

withoutcorrectivelenses.2

PotentialcomplicationsCataractsurgeryisusuallyverywelltolerated.Note,however,thatanysurgicalinterventioncarriesa

riskofcomplications.Ifyounoticeasuddendecreaseinyourvisualacuityorifyoureyebecomes

painfulorred,youmustconsultyourophthalmologistimmediately.


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Potentialcomplicationsincludeaneyeinfectioncalledendophtalmia,glaucoma,retinaldetachment,

implantdisplacement,ormacularoedema.However,thesecomplicationsareveryrare2.

Another,morecommoncomplicationofcataractsurgeryisthedevelopmentofasecondarycataract,

calledaposteriorcapsuleopacification.Inthiscase,thecrystallinecapsulewhichsurgeryleftinplace

becomescloudyagainandsymptomsreappear.Thiscomplicationisobservedin18%ofpatients

within1yearaftersurgeryandin38%within9years1.Secondarycataractsdevelopgraduallyand

progressivelywithtime,usuallyoccurringbetween3monthsand4yearsfollowingsurgery1.Laser

treatment,calledcapsulotomy,isthetreatmentofchoiceinthecaseofthiscomplication.1

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References

1Affsaps,HauteAutoritdeSant.Miseaupointsurlesimplantsintraoculairesmonofocaux

utilissdansletraitementchirurgicaldelacataracte.Avril2008.p.14.

2TheRoyalCollegeofOphthalmologists.Cataractsurgeryguidelines2004.p.6.

3ANAES.Evaluationdutraitementchirurgicaldelacataractedeladulte.Fvrier2000.p.4.

4MillarWJ. Problmes de vision chez les personnes ges.Dans: Rapports sur la sant.

Volume16n1.StatistiqueCanada.2004.p.4954.

5 InstitutScientifiquede laSantPublique.Enqutedesantpar interviewBelgique2004.

LivreII Chapitre2:Maladiesetaffectionschroniques.2006.p.667.

6OrganisationMondialedelaSant.Prventiondelaccitetdesdficiencesvisuelles

Cataracte.

http://www.who.int/blindness/causes/priority/fr/index1.html.

7BeersMH,PorterRS,JonesVTetal.Cataracte.Dans:LemanuelMerck.MerckResearch

Laboratories2006,p.9112.

8BaudouinC,FlixD.Certainstraitementspeuventilsprovoquerunecataracte.Dans:

Cataracte Guidelusagedespatientsetdeleurentourage.Bash2008,p.51.

9MalecazeF.Lachirurgiedelacataractechezlediabtique.Journalfranais

dophtalmologie2003;26:5257.

10Confrenceeuropennesurlesmaladiesrares.Luxembourg,2122juin2005.p.21.

11BaudouinC,FlixD.Lacataracteestellerversible?Atteintelletoujourslesdeuxyeux?

Dans:Cataracte Guidelusagedespatientsetdeleurentourage.Bash2008,p.43.

12AncelJM.Lesprogrsdelacataracteen2008.EmmoiresdelAcadmieNationalede

Chirurgie2008;7:4344.

13BaudouinC,FlixD.Surquelscritreslophtalmologisteprendilladcisiondeproposer

uneintervention?Dans:Cataracte Guidelusagedespatientsetdeleurentourage.Bash

2008,p.6970.

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