Cataract surgery

CATARACT SURGERY IN CANINES WITH SPECIAL REFERENCE TO INTRAOCULAR LENS IMPLANTATION

1. Prepared by:
Dr IrawatiP. Sarode
Assistant Professor
College of Veterinary & Animal Sciences, Parbhani
MAFSU,Nagpur
Department of Veterinary Surgery & Radiology
CATARACT SURGERY IN CANINES
WITH SPECIAL REFERENCE TO
INTRAOCULAR LENS IMPLANTATION

2. STRUCTURE OF NORMAL EYE

3. CATARACT
✓Thetermcataractcomprisesacommongroupof
oculardisordersmanifestedaslossoftransparency
oflensoritscapsule
✓Cataractreferstogroupoflensdisordersofvarying
ageofonset,speedandextentofprogression
appearance&etiology

4. CATARACT CLASSIFICATION
✓Stage of development (maturity)
oIncipient
oImmature
oMature
oHypermature
oMorgagnian
✓Age of development
oCongenital
oDevelopmental
oJuvenile
oSenile
oAcquired
✓Position within the lens
oAnterior capsular
oAnterior sub capsular
oCortical
oEquatorial
oNuclear
oPosterior sub capsular
oPosterior capsular
✓Etiology or pathogenesis
oPrimary:Inherited
oSecondary: Traumatic
Intraocular disease
Nutritional
Radiation
Diabetic
Toxic
✓Consistency
oFluid
oSoft
oHard

5. DEGREE OF MATURATION
1.Incipient cataract2.Immature cataract.
3.Mature cataract 4.Hypermature cataract

6. LOCATION WITHIN LENS
Sub capsular Lamellar cataractAnterior polar Partial cataract
Nuclear cataract Cortical cataract
Total cataract
Posterior cataract

7. ETIOLOGY
Traumatic cataract Nutritional cataract Toxic cataract
Diabetic cataract Cataract due to PRA

8. TREATMENT
✓MEDICAL THERAPY
•Improvementofvisioninearlystagesofcataract,orin
advancedstagesofresorptionwithuseofmydriatics
•Diabeticcataracts:Aldosereductaseinhibitors
(systemic&topical)
•Antioxidants:Selenium-vitaminE
Orgotein(superoxidedismutase)
Zincascorbate
Carnosine
•Otheralternativeremedies:Grapeseedextract

9. SURGICAL TREATMENT
Potentialcataractpatientsshouldbereferredasearlyas
possible
•Cataractsurgeryisonlymeansoftreatment
•Cataractsurgeryisanelectiveprocedure
•Ageofthepatientnotacontraindication
•Typesofcataractunsuitableforsurgery.
e.g.,cataractssecondarytootherinheritedeyediseases–
generalizedprogressiveretinalatrophy(GPRA),
post-traumaticcataracts
cataractsecondaryto,orassociatedwith,uveitis

10. SURGICAL CORRECTION
✓Discission and aspiration
✓Intracapsular extraction
✓Extracapsular extraction
✓Phacoemulsification :
1. One –handed
a. V shaped Phacoemulsification
b. Nuclear flip technique
2. Two -handed / bimanual
a.Nuclear segmentation
b.Divide and conquer
c.Chip and flip
d.Croissant
e.Phaco chop
f.Stop & chop
g.Split and lift

11. PATIENT SELECTION
✓Complete medical history
✓General physical examination
✓Temperament
✓Complete ophthalmic history
✓Complete ophthalmic examination
•Schirmer tear test
•Slit lamp examination/ biomicroscopy
•Fluroscin staining test
•Ophthalmoscopy
•Tonometry
•Gonioscopy
•Fundoscopy
•Electroretinography
•Retinal ultrasound :
oB-mode ultrasonography (10 MHz)
oHigh resolution ultrasound (20 MHz)
oUltrasound biomicroscopy (50-100 MHz)

12. PREOPERATIVE COMPLICATIONS
✓KCS
✓Corneal disease
✓Eyelid deformity
✓Retinal degeneration
✓Retinal detachment
✓Lens induced uveitis
✓Posterior synechiae
✓Lens subluxation
✓Vitrous presentation
into anterior chamber
✓Lens capsule rupture
✓Diabetes mellitus

13. PREOPERATIVE THERAPY
✓Broadspectrumtopicalophthalmicantibioticsevery6hrs
for24-48hrspriortosurgery
✓Topicalcorticosteroidsfor48-72hrspriortosurgeryorup
to4weeks(ifLIUispresent)
✓Topicalnonsteroidalantiinflammatoryagentsevery30
minutesbeginning1-3hrspriortosurgery
✓Mydriasiswith1%Atropine1-2hrspriortosurgery
✓BolusofIVantibioticsatinductionofanesthesia
✓Systemicnonsteroidalantiinflammatoryagents
✓Systemiccorticosteroids

14. ANESTHESIA
✓Generalanesthesiawithsystemicneuromuscular
blockingagents(NasiesseandDavidson1991)
•InductionofGAusingroutineprocedures,&
maintenancewithisoflurane/methoxyflurane
inhalation
•AtracuriumorPancurium
•InductionofgeneralanesthesiawithPropofol(5mg/kg)
,atropine0.03mg/kgSC&Xylazine1mg/kg,IMas
premedicant,incombinationwithperibulbarnerve
blockusing2%LignocaineHCL

15. INCISION SIZE

16. Site Advantages Disadvantages
Limbal Easy to convert to ECCE
Instruments don't distort
cornea
Induces astigmatism
Always requires suture
Iris prolapse more common
Conjunctival manipulation & cautery
Eye is red after surgery
Scleral Rarely induces astigmatism
Seals nicely
Hard to convert to ECCE
Technically difficult
Iris prolapse more common
Conjunctival manipulation & cautery
Instruments distort cornea
Eye is red after surgery
CornealRare astigmatism
No cautery or conjunctival
manipulation
Eye is white after surgery
Hard to convert to ECCE
Technically difficult
Instruments distort cornea
Increased risk of endophthalmitis

17. DISCISSION AND ASPIRATION
•Openingcorneaandanteriorlenscapsule
•Irrigationandaspirationtoremovethecontents
fromwithinthecapsule
•Restrictedtoyounganimalswithliquid
cataracts/animalswithverysmalleyes(usually
exoticpets)

18. EXTRACAPSULAR CATARACT EXTRACTION
(ECCE)

19. INTRACAPSULAR CATARACT EXTRACTION
•Removalofentirelenswithoutopeningortearinglens
capsule
•Methodrestrictedtoremovalofluxatedlens,following
tearingofzonules
•Minimalpostoperativeinflammation
•Anteriormovementofvitreousbody
•Combinationoftechniquewithprophylacticvitrectomy
•ImplantationofsyntheticIOLfixedbysuturesinciliary
sulcus
oBarrieragainstvitreousmovement
oToimprovepostoperativevision

20. PHACOEMULSIFICATION
•Requires smaller incision in either sclera or clear cornea(5.5 -
3.2 mm or less) on the side of the cornea
•Insertion of small probe into the eye
•Ultrasonic waves soften and break up cloudy center of the lens
•Removal bysuction
Phacoemulsification hand piece

21. VISCOELASTIC DEVICES
1. Maintain
space:
e.g. AC during rhexis
bag during IOL insertion
Cohesive best
2. Create
space:
e.g. Creating sulcus
shift lens material
Cohesive best
3. Sealing off:
e.g. Sealing capsular tear
keeping iris away
Dispersive best
4. Coating:
e.g. Protect corneal endothelium
Lubricate cornea
Dispersive best

22. ARSHINOFF SHELL TECHNIQUE
✓Phase I during CCC
1.PlacedispersiveOVD
2.PlacecohesiveOVDjustover
lens
3.Dispersivepusheduptocoat
endothelium
4.Assoonasphacostartscohesive
isaspirated&dispersivecoating
remains
✓Phase II during IOL
insertion
1.PlacecohesiveOVDinthebag
2.PlacedispersiveOVDjustinside
woundtosealpriortoIOL
placement
3.WhenIOLisinserted,dispersive
helpstokeepcohesiveinplace;
bagformed

23. CAPSULORHEXIS
✓Basic techniques
•Continuous curvilinear
capsulorhexis (CCC)
a.Cystitome
b.Combo
c.Forceps
•Can opener

24. HYDRODISSECTION
•Freerotationoflenswithincapsularbagfacilitatingits
fragmentation
•Performedimmediatelyaftercapsulectomywithirrigation
solutioninjectedthrough25-27-gaugecannulaattachedto3
mlsyringe
•Requiresmultipleinjectionsindifferentquadrantoflens

25. PHACOEMULSIFICATION
GOAL
✓To remove lens with minimum
ultrasound to reduce damage to
cornea
TREND
✓To use increasing vacuum &
decreasing ultrasound power to
remove nucleus
Phacoemulsification Unit
BASIC TECHNIQUE
✓Sculpting
✓Nuclear segmentation
✓Nuclear removal

26. PHACO LOCATION
a)Endocapsular
b)Supracapsular
c)Anterior chamber shell
d)½ bag ½ anterior chamber

27. PHACO LOCATION ADVANTAGES DISADVANTAGES
Endocapsular No flip required
Energy away from
cornea
Tear anterior capsule
with chopper or phaco tip
Supracasular Less risk of heating
anterior capsule
Energy closer to cornea
Nuclear flip close to
cornea
AC Shell Little stress on bagEnergy closer to cornea
Slow
½ AC ½ Bag Less risk of heating
anterior capsule
Energy closer to cornea

28. SCULPTING
•Performedbyengagingsuperiorcortex&
nucleuswithventraledgeofneedlealways
withbevelup,&pushingneedleacrosslens
from12-to6-o’clockposition
•Phacoemulsificationpowercontrolled
linearlytomakeefficientsculpting
•Youngdogs:40%power&inolderdogs:85
-90%
•Powerincreasedwhilereachingcentrallens
thengraduallydecreasedwhileproceeding6-
o;clockposition

29. NUCLEAR FRAGMENTATION
✓Single most important step in 2-handed phacoemulsification
✓Quick isolation & mobilization segment of nucleus
✓Nuclear bowl rapidly collapsed inward & fragmented
✓Phaco needle & nucleus rotator positioned against opposite
sides of groove

30. ASPIRATION
•Aspirationoflooselenscorticalmaterialby
positioningI/Acanulaasfarperipherallyin
capsularbagaspossible
•Strippingofcorticalmaterialfromequator&
towardscapsulectomy
•Positioningcanulatipupwardtoaspiratedifficult
toremovefragments

31. DIVIDE AND CONQUER METHOD
•Rotationoflensto90%afterbeingfractured
•Creationof4isolatedfragments
•,Displacementofisolatedlensfragmentstoward
pupil,wheretheycabeeasilyfragmented

32. INTRAOPERATIVE COMPLICATIONS
✓Anterior capsular fibrosis
✓Intraoperative miosis
✓Expanding vitreous
syndrome
✓Iris prolapse
✓Intraoperative hemorrhage
✓Vitreous presentation
✓Cavitation bubbles
✓Phaco machine failure
✓Lenscapsule
a.anteriorradialtears
b.posteriorcapsuletears
c.polishingopacities
d.zonulartearsordehiscence
✓Displacedordislocated
lensfragments

33. INTRAOCULAR LENSES

34. MATERIALS OF INTRAOCULAR LENSES
A.Thermoplastics
B.Synthetic elastomers
C.Acrylate polymers
1. Hydrogel & hybrid hydrogel lenses
2. Soft acrylic IOLs
3. Collamer IOLs

35. TYPES OF INTRAOCULAR
LENSES
1.Traditional
2.Monofocal
Multifocal
3.Accomodating
4. Aspheric
5. Blue light filtering
6.Toric
7. Light adjustable
8. Piggyback

36. ✓TwomaintypesofIOLsusedinveterinarymedicine
•Nonfoldable,Hard–PMMA
•Foldable–silicon&acrylicpolymers
✓Latesttypeofsoftlensesdesignedfordogsmadeof
hydrophilicacrylate
✓Lensesimplantedwithincapsularbag
✓Anteriorchamber&irissupportedlensesnotused
(highextendofcomplications)
✓Opticpower-41D
✓Sizedifferfrom14-18mm(hapticsize)
7mm(opticsize)

37. PARAMETERS OF CANINE
INTRAOCULAR LENSES
Style Posterior chamber
Design One-piece, biconvex
optic
Sterilization Ethylene oxide
Optic Polymethymethacrylate
Optic size 7 mm
Haptic length 14-18 mm
Haptic configurationModified “C” loop
Haptic forward angulation2-15º
•Dialing holes on the optic
•Suture holes on the haptics
•Lenses vaulted at 10º -12º
CONVENTIONAL IOL

38. ✓Injectable by 2.8 mm incision
✓25% hydrophilic acrylic
✓360º square edges
✓10º haptic angulation
✓Power 41 D

39. Folded IOL
✓Folded&placedinspecialforceps
✓IncisionsizegrowsbitwithincreasedpowerofIOL-
3.5mm
✓Moustachestylefold:widerincisionbuthapticsflow
intobag
✓Axialstylefold:smallerincisionbuthapticneeds
guidance

42. SUTURE FIXATION OF IOL
1.Sutureispassedbeneath
iristoexitsclera2mm
posteriortolimbus
2.IOLhapticpulledinto
ciliarysulcusastension
isplacedonsuture
1.Ab interno method

43. 2. Ab externo method
1.Suture1
st
preplaced
bythreadingsuture
needlethroughciliary
sulcus&intolumen
ofahypodermic
needle
2.Lensanchoringsuture
pulledintotheposterior
chamber

44. ✓Afterlenshasbeen
extracted,lensanchoring
suturepulledthrough
incision,cut&tiedto
eachhapticofIOL
✓AfterIOLhasbeen
positioned,incisionis
closed&IOLanchoring
suturestiedtoexternal
sclera

45. WOUND CLOSURE
✓Useof8-0to10-0monofilamentabsorbable
suturematerialwithsimpleinterruptedor
simplecontinuoussuturepattern
✓Useofsuturepattern&degreeoftightness
toprovidewatertightsealwithoutcreating
astigmatism

46. POSTOPERATIVE COMPLICATIONS
IMMEDIATE VERSEUS LONG TERM
✓IMMEDIATE
✓Corneal ulceration
✓Wound dehiscence within 3
days post surgery
✓Surgery induced corneal
astigmatism
✓Corneal edema
✓Ocular hypertension (post
operative pressure spike)
✓Uveitis
✓Fibrin in the AC
✓Hyphema / vitreal hemorrhage
✓Acute endophthalmitis
✓Toxic anterior segment
syndrome (TASS)
✓LONG
✓Posteriorcapsularopacities
(PCO)
✓IOLdecentration
✓IOLluxationoutofthebag
✓Glaucoma
✓Retinaldetachment
✓Cornealedema
✓Endophthalmitis
✓Cornealstromalabscess

47. POST OPERATIVE CARE
✓Carefulhandlingofpatient
✓Freedomfromexcitement,
Keepdogcalmandquiet
✓KeeptheElizabethancollar
onatalltimesfor1to3
weeksaftersurgery,tokeep
himfromhurtinghimself
✓Avoidrubbing,pressing,
massaging,heat,dust,dirt
andbrightsunfor1month

48. ✓Broadspectrumsystemic
antibioticfor5-7days
✓Instillationofmydriaticeye
drops2-3timesdaily
✓Instillationofantibioticeye
drops3-4timesdaily
✓Instillationof anti-
inflammatoryeyedrops4
timesaday

49. ✓Useaharnessinsteadofacollarwhenonwalks
toreducepressureonhishead(andeye)from
pulling
✓Cancelallgroomingandvaccination
appointmentsforabout6weeks
✓Avoidswimming,splashingofwateroneyesfor
1month
✓Avoidstrenuousphysicalactivityfor1month
✓Dailycheckupforfirsttwoweeks
✓Scheduleandkeepallfollow-upappointments

50. Thank you…