CataractNot Just an Old Dog

DiseaseJessica McDonald, DVM, DACVO

Fox Valley Animal Referral Center

Lens Anatomy• Biconvex clear structure

• Located between iris and the anterior vitreous� Held in place by the zonules

• Depends on aqueous humor and vitreous for nutrition and waste removal� No blood vessels

• Composed of lens capsule, lens epithelium, and lens fibers

• Dog size: 10.5 mm wide by 7.5 mm deep

• Cat size: 9–10.4 mm wide by 7.5 mm deep

Cataracts

• Any age• Any location in the lens

• Cataracts partially or completely block tapetal reflection and fundic examination and are often classified by stage of maturation and etiology

Types of Cataract• Incipient• Immature• Mature• Hypermature• Morgagnian

Types of Cataract• Incipient• Immature• Mature• Hypermature• Morgagnian

Types of Cataract• Incipient• Immature• Mature• Hypermature• Morgagnian

Types of Cataract• Incipient• Immature• Mature• Hypermature• Morgagnian

Location• May provide potential cause and progression risk.

� Photo document if possible!

• Subcapsular• Cortical• Equatorial• Nuclear

Primary Cataract• Most common presentation in dogs!

� Juvenile, Adult onset� MANY Breeds

• Genetic basis• No trauma, inflammation or metabolic disease• Bilateral, likely symmetrical• Progression varies among breeds and individuals• Few genetic tests available • Dam/sire and littermates should be examined if able� OFA Exam??

Young Dog-Inherited Cataract

PHPV/PTVL

PHPV/PTVL

PHPV/PTVL

PHPV/PTVL

PHPV/PTVL

Secondary Cataract• Occur secondary to trauma, inflammation or concurrent metabolic disease processes (ocular or systemic)

• Diabetic• Uveitic• Toxic (Retinal disease)• Others: Hypocalcemic, Degenerative, Traumatic, Nutritional, Radiation-induced

Diabetes• Second most common cataracts in dogs• Hyperglycemiaà Sorbitol accumulates in the lensà Osmotic influxà

Cataract• First signà Vacuoles at the lens equator (need dilation)• Progress rapidly and become swollen (intumescent) with severe

phacolytic uveitis� Risk for lens capsule rupture

• Literature: 75%-80% of diabetics develop cataracts within 6 to 12 months of disease onset…� My clinical impression is higher and sooner….� Regulation INDEPENDENT!

• Acute cataract formationè Check blood glucose!

Diabetes-Equatorial Vacuoles

Diabetes-Intumescence

Diabetes-Hypertriglyceridemia

Lipemic Flare

Diabetes-Hypertriglyceridemia

Uveitic• Any severe intraocular inflammation of any cause can result in cataract development

• Phacolytic versus Phacoclastic

� Lytic= Slow release of lens proteins over time, Slow cataractogenesis

� Clastic= Rapid release of lens proteins, Rapid inflammation, Rapid cataractogenesis

Uveitic•Need to rule out causes of uveitis�Neoplastic� Infectious� Inflammatory�Traumatic� Penetrating trauma from a sharp object (eg, cat claw, plant

thorn)� Blunt trauma, corneal trauma, or foreign material in the

anterior chamber can also cause cataract development

Puppy Vs. Cat Phacoclastic uveitis (WORSE)

Puppy Vs. Porcupine Phacoclastic uveitis (WORSE)

Toxic• Retinal degeneration• Progressive retinal atrophy (PRA)• Retinal detachment

• Dying photoreceptor cells are hypothesized to produce toxic aldehyde metabolites that progressively damage the lens à Cataract

PRA/Retinal Degeneration

PRA/Retinal Degeneration

Cataract Examination• PLR (Direct and consensual)àSubcortical

� Cataracts alone will never alter the PLR

• Dazzle reflexà Subcortical (NOT vision)

• Menace responseà Vision

• Cotton Ball Testingà Vision

• Schirmer tear testà >15-20mm/min wetting in 60 seconds

• Fluorescein stain

• Intraocular pressure (IOP)àLess than 20mmHg (Watch for uveitis!! LOW IOP)

• Anterior chamber assessment for aqueous flare

• Lens assessment (Dilated if possible)

• Fundic examination if possible (Dilated if possible)

• Complete Physical Examination

Uveitis and IOP• Uveitis mediated by intraocular prostaglandins• Prostaglandins drive IOP down• Low IOP = Uveitis

• IOP of 15-20 AND Severe Uveitis….� Is likely GLAUCOMA once inflammation is controlled� Consider anti-glaucoma medications if high-normal IOP with uveitis

• Latanoprost (prostaglandin analogue) contraindicated in uveitis??� Unclear

Aqueous Flare

Keratic Precipitates (KPs)

Keratic Precipitates (KPs)

Cataracts vs Lenticular Sclerosis• AKA Nuclear Sclerosis• Normal aging change in dogs age 7 years or older• Increased density of the lens nucleus� “Spherical haze” in the axial lens

• Does NOT block tapetal reflection• Older dogs may have both nuclear sclerosis and cataracts• No treatment or monitoring for only lenticular sclerosis

Lenticular Sclerosis

Lenticular Sclerosis

Phacolytic Uveitis• Intraocular inflammation secondary to leakage of lens protein is the most common complication of untreated cataracts•Leads to corneal endothelial damage, synechiae, and secondary glaucoma long-term�Risk increases with time�Aggressive treatment with ophthalmic steroids and topical ophthalmic NSAIDs

Treatment•Topical Anti-inflammatories

•Aldose Reductase Inhibitors??

•Phacoemulsification�Ocular ultrasound, Electroretinogram, Gonioscopy

Once a cataract forms, cataract surgery is the only definitive treatment method to restore vision (so far)

Topical Anti-Inflammatories• Diclofenac 0.1% ophthalmic

• Ketorolac 0.4% OR 0.5% ophthalmic

• Flurbiprofen 0.1% ophthalmic

• Prednisolone Acetate 1% ophthalmic� NOT DIABETICS

• Neo-Poly-Dexamethasone� Outside Inflammation > Inside

No Surgery? No problem• Long-term topical ophthalmic steroids negatively impact corneal

health, uveitis should ideally be controlled with topical ophthalmic NSAIDs when surgery not considered� Corneal mineral formation� Risk of corneal ulceration� Change in conjunctival microflora

• Generally, if no surgery…� Recommend IOP monitoring every 3 months� Full ophthalmic examinations every 6 months

Aldose Reductase Inhibitors

(ARIs)Kinostat®Kinostat is a topical aldose reductase inhibitor that is anticipated to receive FDA approval in the Winter 2016 / Spring 2017. FDA toxicological approval was received in Spring, 2015 and the multi-centered clinical trial was completed in January, 2016.

ARIs

ARIs

http://therapeuticvision.com/our-products/kinostat/

Can-See

Can-See• Can-C™ Ingredients:

• N-a-Acetyl-Carnosine (NAC) 1.0% (approved by IVP) (ANTIOXIDANT)

• Glycerin (lubricant) 1.0%

• Carboxymethylcellulose sodium (lubricant) 0.3%

• Excipients:

• Sterile Water (Ophthalmic Grade Isotonic Solution, pH 6.3 to 6.5) buffered with Potassium Phosphate Dibasic and Potassium Phosphate Monobasic

• Benzyl Alcohol (Preservative)

Phacoemulsification• Early referralà Better Outcome

� Staging of the cataract� Fundic exam may be possible

� Rule out retinal diseases such as Progressive Retinal Atrophy� Evaluation and early treatment for mild lens-induced uveitis

� Inflamed eyes = Decreased prognosis for vision� Determination of cause� Evaluation for concurrent diseases

� Keratoconjunctivitis sicca, corneal dystrophy, PRA, glaucoma, synechiae

• Cardiac status• Diseases related to anesthesia• Metabolic illness, such as diabetes or Cushing's disease• Internal medicine concerns• Any drug sensitivities

Diabetes• Must be well-controlled before

cataract surgery pre-testing� Fine tuned machine!

• CBC

• Serum chemistry

• Urinalysis +/- urine culture

• Fructosamine (Excellent to Good range)

• Blood glucose curve� Nadir of 100-120mg/dL ideal

• Fasting triglycerides

Post-operative Complications• Prognosis for vision after surgery: 80%� Breed dependent!!� Newer cataract = Less phacolytic uveitis = Less complications

• Retinal detachment (8.4%) � Shih Tzu, Boston Terriers

• Glaucoma (6.7%)� Boston terriers, Labrador retrievers � Postoperative ocular hypertension may be transient or persistent.

� Up to 2 weeks post-operatively is the key risk period, but is a lifetime risk due to chronic uveitis

Post-Operative Management• Intensive but necessary for success!!!• 4 to 6 eye drops up to 4-6 times per day for the first 1-3 weeks

post-operatively • Frequent postoperative rechecks

� 24hrs post-op, 1 week, 3 weeks, 6 weeks, then every 3-6 months

• Protective Elizabethan collar for 2-3 weeks postoperatively� Suture is 8-0!

Cataracts in Cats• Congenital cataractsà Rare

� Birman, Himalayan

• Primary cataractsà Also rare

• Secondary cataractà Most common� Anterior uveitisà MOST COMMON ETIOLOGY� Traumaà Cat claw injuries� Glaucoma� Lens luxation (common sequelae of anterior

uveitis)� Infectiousà Encephalitozoon cuniculi?� Metabolicà Diabetic cataracts uncommon due to

low aldose reductase activity

Cataract Surgery in Cats• Performed similarly to that in dogs• Success rate higher than in dogs? Less inflammation? � Chronic uveitis and secondary cataractà Guarded prognosis

• Post-traumatic ocular sarcoma (PTOS) is risk!� Months to years after traumatic event (avg 7 years)� Avg survival time after enucleation 1 month to 1 year� Avg survival time after lens surgery was 4.3 years

� Enucleation better for lens luxation or cataracts??

Post-Traumatic Ocular Sarcoma

PTOS-Rabbit

Thank you!

Personal Favorite…

Electrocution

References• Dickinson, R., Bauer, B., Gardhouse, S., & Grahn, B. (2013). Intraocular sarcoma associated with a

rupture lens in a rabbit ( Oryctolagus cuniculus. Veterinary Ophthalmology, 16, 168-172.

• Dubielzig, R.R., Everitt, J., Shadduck, J.A., & Albert, D.M. (1990). Clinical and morphologic features of post-traumatic ocular sarcomas in cats. Veterinary Pathology, (1), 62-65.

• Duke, F., Strong, T., Bentley, E., & Dubielzig, R. (2013). Feline ocular tumors following ciliary body ablation with intravitreal gentamicin. Veterinary Ophthalmology, 16, 188-190.

• Gelatt, K., Gilger, B., & Kern, T. (2013). Veterinary ophthalmology (5th ed.). Ames, Iowa: Wiley-Blackwell.

• Kador, Peter F., Webb, Terah R., Bras, Dineli, Ketring, Kerry, & Wyman, Milton. (2010). Topical KINOSTAT[trademark] ameliorates the clinical development and progression of cataracts in dogs with diabetes mellitus.(Clinical report). Veterinary Ophthalmology, 13(6), 363.

• Lim, C., Bakker, S., Waldner, C., Sandmeyer, L., & Grahn, B. (2011). Cataracts in 44 dogs (77 eyes): A comparison of outcomes for no treatment, topical medical management, or phacoemulsification with intraocular lens implantation. The Canadian Veterinary Journal = La Revue VeterinaireCanadienne, 52(3), 283-8.

• Maggs, D., Miller, P., Ofri, R., & Slatter, D. (2013). Slatter's fundamentals of veterinary ophthalmology (5th ed.). St. Louis, Mo.: Elsevier.

• Martin, C. (2009). Ophthalmic disease in veterinary medicine (Rev. ed.). London: Manson Publishing/The Veterinary Press.

• Photos cited throughout

• Websites cited throughout