cataracts, veterinarian

1. Christa Corbett, DVM, MS, DACVO
November 8, 2014

2. Outline
 Anatomy of the lens
 Nuclear sclerosis vs. cataract
 Stages of cataracts
 Etiologies of cataracts
 When to refer
 Pre-operative care
 Cataract surgery
 Post-operative care
 Medical treatment ???

3. Anatomy
AP
 Zonules
 Lens capsule
 Nuclear vs. Cortical
 Lens epithelium
 Anterior
 Produces new fibers
 Equator
 Active mitosis

4. Nuclear (Lenticular) Sclerosis
 Lens continually produces
new cortical fibers
 Compression of nucleus in
patients over 6-8 years old
 Causes light to scatter
 We can still see retina, patient
is still visual
 Diagnosis:
 DILATION and RETROILLUMINATION
AP

5. RETROILLUMINATION

6. Stages of Cataract
 Incipient - <10%
 Minor opacities, often incidental
 Perfect view of fundus

7. Stages of Cataract
 Early immature – 10-50%
 Obvious opacity, but good tapetal
reflex and good view of fundus

8. Stages of Cataract
 Late immature – 51-99%
 Can still see tapetal reflex, but very
limited view of fundus

9. Stages of Cataract
 Mature – 100%
 No tapetal reflex on retroillumination

10. Stages of Cataract
 Hypermature – resorbing
 Varying degrees of lens opacity
 Wrinkled capsule, “Sparkly” cataract

11. And other minutia terms that
Ophthalmologists love . . .
 Morgagnian – subset of hypermature
 Cortex resorbs, nucleus drops

12. And other minutia terms that
Ophthalmologists love . . .
 Brunescence – Yellow!
 Very old patients, very old cataracts

13. And other minutia terms that
Ophthalmologists love . . .
 Intumescence = FAT
 Quick forming diabetic (occasionally
inherited)

14. Tendency to progress
 Nuclear: rarely
progress
 Cortical: variable,
often progress
(esp. anterior)
 Equatorial: often
progress
AP

15. Etiology
 Inherited
 Diabetes
 Senile
 Trauma
 Uveitis
 Horses
 Cats
 Nutrition
 Irradiation
 Hypo/Hyper Ca2+
 Electrocution
 Toxic
 PRA
 Drugs

16. Diabetes mellitus
 Dogs only!
 75% incidence within one year of onset of DM
 Mechanism of action
 Increased amount of glucose in the eye
 Overloads the hexokinase pathway, so excess
glucose shunted into sorbitol pathway
○ Enzyme Aldose Reductase is responsible for this
shunting
 Sorbitol is too big to diffuse through the lens capsule
 Osmotic gradient = more fluid pulled into lens
○ Vacuolization of proteins
○ Lens protein aggregation

17. Senile Cataracts
 Refers to time of onset, and etiology
 Very slow to progress
 I do not have an age cut off, but I will
NOT do surgery in an elderly dog if
there are signs of:
 Cognitive dysfunction
 Retinal degeneration
 Significant corneal degeneration

18. When to refer
 Do NOT let the cataract “ripen!”
 The earlier the better
 It may be possible to get a view of the retina
in early cases
 Start anti-inflammatory therapy before
problems arise
 Clients can prepare themselves
and save money, take vacation
time, etc.

19. Sequelae of cataracts if surgery
not performed early . . .
 Loss of vision
 Lens induced uveitis:
 Cataractous lens proteins
leak out of lens  uveitis
 Lens capsule rupture
 Lens luxation
 Secondary glaucoma
 Retinal detachment
 Capsular mineralization

20. Treatment before referral
 Anti-inflammatory therapy
 If cataract is immature or beyond
 Topical steroid
○ Prednisolone Acetate ($$$)
○ NeoPolyDex
 Topical NSAID
○ Diclofenac
○ Flurbiprofen
 Quiet eye: SID-BID
 Hyperemic, miotic, aqueous flare: TID-QID
○ Consider an oral NSAID as well
 Check bloodwork for diabetes
 Monitor for glaucoma if possible

21. Retinal Testing
 Outpatient testing, typically half-day
hospital stay
 Sedation is rarely necessary
 Retinal FUNCTION
 Electroretinogram
 Retinal STRUCTURE
 Ocular ultrasound

22. Retinal Testing

23. Artificial lenses
 Placed in every eye if possible
 Cannot be placed with:
 Zonular instability
○ Risk of future lens luxation
 Ruptured lens capsule
○ Iatrogenic or pre-op (especially diabetics)
 Hypermature cataract with immense
capsular contraction = too small to hold a
lens

24. Artificial lenses
 Rigid 
 Polymethylmethacrylate (PMMA)
 Requires an 8mm corneal incision
○ More risk of astygmatism or incisional leakage
 Foldable 
 Acrylic 
 Silicone
 Folds into injection cartridge,
3mm incision

25. Suturing
 9-0 monofilament absorbable suture
(PGA, Vicryl®)
 Smaller than a piece of my hair!
 Suture pattern is surgeon-dependent
 Double continuous, or “Shoe-lace”
9-0 vicryl
6-0 silk
Hair
E-collar is
MANDATORY!

26. Post-Operative Patient
 Patients are immediately visual!

27. Success rates with surgery
 85-95% success for most patients
 Success rate decreases with:
○ Hypermaturity
○ Uncontrolled lens induced uveitis
○ High or High-normal IOPs
 Might be even lower % in certain breeds
○ Bichon (Retinal detachment)
○ Boston Terriers and Pugs (Glaucoma, corneal health)
○ Shih Tzu (Corneal health)

28. Post-op Ocular Complications
 Common:
 Fibrin
 Refractory uveitis
 Secondary glaucoma
 Retinal detachment
 Corneal ulceration
 Posterior capsular opacity
 Rare:
 Artificial lens or capsular luxation
 Hyphema
 Endophthalmitis (sterile or bacterial)

29. Posterior Capsular Opacification
 100% of dogs

30. Minimal PCO in most cases!

31. Hypermature cataract leading to
mineralized capsule plaques

32. Post-operative care
 Enough eye drops to drive our clients crazy!
 4-6 different medications, all QID
○ Anti-inflammatory drops
 Pred acetate and Diclofenac
○ Antibiotics
 Something that will penetrate the cornea = Fluoroquinolone
○ Lubricant gel
 Optixcare gel
○ +/- Glaucoma drops
○ +/- Dry eye meds (only if previously diagnosed)

33. Post-operative care
 Oral medications BID
 Antibiotic (Clavamox or Cephalexin)
 Anti-inflammatory (Rimadyl)
 E-collar!!!
 24-7 for at least 2 weeks!
 Warm compress the eyes to keep clean
of discharge

34. Post-operative care
 Rechecks:
 +/- 24 hours
 +/- 1 week
 2 weeks – taper drops, remove e-collar
 6 weeks
 3 months
 Every 4-6 months for LIFE!
○ Every complication listed can happen even
years afterwards!

35. Rechecks – Primary care vet
vs. DACVO?
 Every single recheck:
 Schirmer tear test
 Intraocular pressure
 Slit lamp anterior exam
○ Corneal health
○ Grade of aqueous flare
○ Grade of Posterior cortical opacity (PCO)
○ Lens position (subluxation, centration of IOL)
 Indirect fundic exam
○ Retinal position – must look all the way out to the
ora ciliaris retinae, most common area for detachments
to begin
○ Signs of retinal hemorrhage
○ Signs of subretinal edema
○ Signs of vitreal degeneration

36. Non-surgical patients
 Topical NSAIDs for life (SID-BID)
 Monitor IOP every 3-4 months
 Painful:
 Glaucoma, uveitis and lens luxation
 Non-painful:
 Retinal detachment and hyphema

37. Will medical treatment eliminate
cataracts?
 Cataractogenesis
 Denaturation of lens proteins
○ Physical disruption of lens fibers
 Trauma
○ Altered osmotic gradients
 Diabetes
○ Oxidative damage
 Aging
○ Genetic predisposition

38. • Thirty dogs treated for at least 2 months
• Reduction of lens opacity in dogs with
immature cataract or nuclear sclerosis
• Owner reports “suggested” improved visual
behavior in 80% of cases

39. • In vitro
• Grapeseed extract
• Significant inhibition of mechanisms
of oxidative stress
• In vivo studies not yet presented
AJVR 2008

40. • Controlled study
• 12 months
• Drop given TID OU
• Significant inhibition of
cataract when given at
time of DM diagnosis

41. Questions???