Ophthalmic problems in the geriatric patient (Proceedings)

GERIATRIC CORNEAL DISEASES

- CORNEAL CALCIUM DEGENERATION

     ■ Calcium is deposited in the anterior to deep stroma of the cornea

     ■ Secondary to systemic disease or age

          • Hypercalcemia, Hyperphosphatemia, Hyperadrenocorticism, Uremia, Hypervitaminosis D

     ■ Complications to Calcium Degeneration

          • Pain when Calcium is exposed because of rough corneal surface

          • Progressive vision impairment

          • Sloughing of calcium

          • Neovascularization into calcific areas

     ■ Treatment for Calcium Degeneration

          • Topical EDTA (1-5%)

          • Trichlorcetic Acid

          • Superficial Keratectomy

- REFRACTORY CORNEAL ULCERS

     ■ Also known as:

          • Indolent ulcers, non-healing ulcers, Boxer ulcers, rodent ulcers, Recurrent corneal erosion syndrome, Spontaneous chronic corneal epithelial defects (SCCED)

     ■ Clinical Signs

          • Loosely adherent epithelium (lipping)

          • Blepharospasms

          • Neovascularization with chronicity

     ■ Underlying Pathophysiology

          • Absence of continuous basement membrane

          • Decrease in hemidesmosomes

          • Extracellular Matrix abnormalities

     ■ Complications of Refractory Ulcers

          • Chronic discomfort, Corneal infection, Corneal neovascularization, fibrosis, and vision loss

     ■ Treatment for Refractory Ulcers

          • Q-tip Debridement

               » 15-25% success rate

          • Linear Grid Keratotomy or Multiple Punctate Keratotomy

               » 95% success rate

          • Others (less than 50% success rate)

               » Contact lens, Third eyelid flap, Chemical cauterization, Topical growth factors

- CORNEAL ENDOTHELIAL DEGENERATION

     ■ Spontaneous, progressive corneal edema

     ■ Abnormal dystrophic endothelial cells

     ■ Prevalent breeds

          • Boston Terrier, Chihuahua, Dachshund, Poodle

     ■ Pathology of Endothelial Degeneration

          • 2500-2800 cell/mm2 in the dog

          • Endothelial cells pump fluid from the cornea into the aqueous, keeping the cornea clear and dehydrated.

          • As cells become dystrophic and die, the remaining cells enlarge to compensate.

          • Once there are <500-800 cells/mm2 , compensation is lost and fluid is not adequately pumped out of cornea.

     ■ Complications to Endothelial Degeneration

          • Epithelial microbullae formation, Corneal ulcers, Keratoconus, Bullous keratopathy, Vision loss

     ■ Treatment

          • Hyperosmotic Agents (5% sodium chloride ointment)

               » May decrease extent of epithelial bulla formation

               » Does not allow for significant cornea clearing

               » Decreases thickness of cornea

          • Thermokeratoplasty if chronic erosions

          • Penetrating Keratoplasty

               » Improve vision

               » Fresh donor cornea

               » Complication- graft rejection, dehiscence, infection

GERIATRIC LENS DISEASES

- NUCLEAR (LENTICULAR) SCLEROSIS

     ■ Occurs in all dogs older than 7 years of age

     ■ Secondary to progressive lens fiber formation and internal compression of older lens fibers, especially those in the nucleus

     ■ The compressed lens fibers cause light-scattering, leaving a whitish-blue appearance on diffuse illumination

     ■ With retro illumination, a tapetal reflex is visible and an outline or zone of the lens nucleus may be apparent

     ■ Funduscopic examination is still possible

     ■ Causes depth perception issues in advanced age

- CATARACTS

     ■ Diabetic or Senile in origin

     ■ Phacoemulsification

GERIATRIC VITREAL DISEASES

- ASTEROID HYALOSIS

     ■ Characterized by many small refractile particles (0.03 to >0.10mm in diameter)

     ■ Consist of calcium or phospholipids

     ■ Age related or secondary to retinal degeneration, inflammation, intraocular tumors

     ■ No distinct influence on vision unless advanced

- SYNERESIS

     ■ A degenerative breakdown of the vitreal gel that separates the liquid from the solid components, resulting in liquefaction and development of fluid-filled cavities within the vitreous

     ■ Breakdown occurs with age

     ■ Predisposes the animal to retinal detachment

GERIATRIC RETINAL DISEASES

- RETINAL DEGENERATION

     ■ Late onset in geriatric dog

     ■ Night vision loss initially

     ■ Ophthalmic findings

          • Mydriasis in ambient light

          • Slow and incomplete pupillary light reflexes

          • Tapetal hyper-reflectivity

          • Retinal blood vessel attenuation

          • Pale optic nerve head

- HYPERTENSIVE RETINOPATHY

     ■ Most common in geriatric cats but also occurs in dogs

     ■ Acute vision loss

     ■ Ophthalmic exam

          • Various types of intraocular hemorrhage

               » Hyphema (can cause secondary glaucoma)

               » Vitreal hemorrhage

               » Sub- and intra-retinal hemorrhages

          • Varying degrees of retinal detachment

     ■ Systolic Blood Pressure is typically >160mmHg

     ■ Pathophysiology of Hypertensive Retinopathy

               » Precapillary vasoconstriction of retinal arterioles

               » This leads to smooth muscle necrosis, vascular dilation, and leakage

               » Serous retinal detachment and hemorrhage occur secondarily

     ■ Other considerations with Hypertension

               » Can be primary, but concurrent disease is common

          • Kidney disease, Hyperthyroidism, Cardiac disease, Hyperglycemia

     ■ Treatment

               » Treat hypertension and underlying systemic illness

               » Kidney disease will worsen with hypertensive treatment

GERIATRIC OCULAR NEOPLASIA

- EYELID AND NICTATATING MEMBRANE NEOPLASIA

     ■ Meibomian Gland Adenoma/Adenocarcinoma

               » Originate in the base of the gland

               » Solitary to coalescing

               » Infiltrative with raised lobulated surface

               » Perilesional hyperemia

               » Distinct margins

               » Benign

     ■ Squamous cell carcinoma of the Eyelid or Nictatating Membrane

               » Usually occur in white cats

               » UV light induced

               » Indented to depressed surface

               » Ulcerated, necrotic, non-healing lesions

               » Irregular and indistinct margins

               » Locally aggressive and high recurrence rate

     ■ Fibrosarcoma of the Eyelid

               » Locally invasive, Slow growing, Coalescing mass, Grey to brown, Occasionally ulcerated, Indistinct margins

     ■ Papilloma

     ■ Hemangioma

- LIMBAL MELANOCYTOMA

     ■ Breeds predisposed

               » Labrador Retrievers, German Shepherds

               » Slow growing in older dogs

     ■ Treatment

               » Debulk and laser photoablation or cryoablation

               » Penetrating keratoplasty if full thickness

- UVEAL NEOPLASIA

     ■ Canine Uveal Melanocytoma

               » Most common intraocular tumor of dog

               » Darkly pigmented, elevated iridial mass or ciliary body mass

               » Typically benign but locally invasive (will lead to secondary glaucoma if left to grow)

               » Treatment

          • Laser Photoablation

          • excision

          • Enucleation if secondary glaucoma or tumor is not amendable to laser

     ■ Feline Diffuse Iris Melanoma

               » Most common intraocular tumor of cat

               » Progressive pigmentation over months to years

               » Extent and amount of pigmentation increase with time

               » Secondary glaucoma occurs in advanced cases because of tumor infiltration into drainage angle

               » Metastasis occurs as late as 1-3 years after enucleation (usually to liver and lungs)

               » Metastatic rate may be as high as 63%, but is not usually noted until death occurs

               » When to Enucleate (controversial)

          • If the pigmented areas are increasing in amount and size

          • If pigmented mass is within the iridocorneal angle (gonioscopy)

          • If there are changes in shape and mobility of the pupil

          • Elevated IOP

          • Pigmented cells floating in the Anterior chamber upon Slit Lamp

               • Laser Photoablation (controversial)

          • Must be done in early stages

          • Potential to spread tumor cells to distant organs during surgery

- CILIARY BODY NEOPLASIA

     ■ Ciliary body adenoma/adenocarcinoma

               » Second most common intraocular tumor of dog

               » Most are non-pigmented, pink, and fleshy

               » Metastasis is rare with adenoma

               » Adenocarcinoma is more invasive, may metastasize, but rare

               » Mass extends through the pupil and/or the iris

     ■ Treatment

               » Excision with histopathology

               » Enucleation

               » Evisceration with intraocular silicone prosthesis (recurrence)

- ORBITAL NEOPLASIA

     ■ Osteosarcoma ,Nasal carcinoma, Meningioma , Fibroma , Lymphosarcoma, Squamous cell carcinoma, Salivary gland adenoma, Liposarcoma, others

     ■ Orbital Neoplasia Symptoms

               » Unilateral Exophthalmos

               » Variable displacement of Globe

               » Third eyelid protrusion

               » Retropulsion of globe is decreased or impossible

               » Vision is usually retained

               » Slowly progressive

               » Non-painful

     ■ Orbital Workup

               » CT or MRI are best for localizing the lesion

               » Ultrasound

               » Fine Needle aspirate, Biopsy

               » Radiographs, looking for metastatic disease

     ■ Treatment

               » Orbitotomy

          • Localized neoplasm without metastasis

          • Preserves the globe

               » Exenteration

          • If globe preservation is not possible

          • Localized neoplasm without metastasis

     ■ Humane euthanasia

               » Advanced stages

               » Most common outcome

References:

1. Essentials of Veterinary Ophthalmology by KN Gelatt; Fundamentals of Veterinary Ophthalmology by Slatter; Small Animal Ophthalmic surgery by KN Gelatt