Exam 1: Diagnosis and Management of Corneal Disease

corneal injury response

• ulceration

• inflammation

• necrosis

• malacia

• fibrosis

• degeneration

Canine corneal diseases

• brachycephalic conformation

• immune mediated keratitis aka pannus

• corneal depositis

• corneal edema 

• corneal ulceration 

effects if conformation on the ocular surface

• pigmenation, vascularizaion, scaring ± ulceration = keratitis

• corneal ulcers

• predisposition for proptosis

• normal STT

• evaluae for prominent eyelid openings, incomplee closure of lids, trichiasis

treatment of the effects of conformation on the ocular surface

• canthal closure and or topical lubricants

pannus aka superficial chronic keratitis

• immune mediated in german shepherds, greyhounds

• initially temporal vascularization, axial advancement causes corneal pigmentation

• typically bilateral, no cure

therapy for pannus 

• topical steroids 3-4x/day initial then taper 

• topical cyclosporine 2x/day good adjunct and maintenance 

• treat to effect- dont taper until blood vessels gone from the cornea 

• requires life long therapy at minimum required frequency 

third eyelid pannus

• aka atypical pannus or plasmoma

• pigmentatio or depigmentation of the third eyelid, thickening

• dx based on clinical exam and cytology, treatment is the same

new developments in pannus treatment

• episcleral cyclosporine implant under conjunctiva can be used for cases that cannot be treated daily due to aggression or owner’s health

• can also be used for KCS

• needs replacement ever year

definition corneal depositis 

• lipid and or mineral accumulation within the cornea 

• results from dystrophy or degeneraion 

corneal dystrophy

• inherited in beagle, siberian husky, shetland sheepdog, cavy, airedale, samoyed, dachschund

• bilateral, symmetrical central corneal opacities hat are not vascularised

• fluorescein negative

• painless wih minimal to no progression

• NO TREATMENT NEEDED UNLESS SHELTIE

sheltie corneal dystrophy

• bilateral and symmetrical, often accompanied by corneal ulceration and pain which is unique to the breed

• epithelial and stromal disease

• treated with topical cyclosporine/tacrolimus BID indefinitely

• topical antibiotics as needed for ulceration

• needs lifelong therapy

corneal degeneration is secondary to ? and looks like ?? 

• metabolic disease, chronic corneal disease trauma, age related change 

  • asymmetrical, vascularized, commonly ulcerative and painful 

types of metabolic diseases that can cause corneal degeneration

• high cholesterol/triglycerides

• hypothyroidism

• pancreatitis

• hyperadrenocorticism

• diabetes

• high fat diet

• storage diseases

• familial hyperlipidemia

treatment of corneal degeneration

• avoid use of topical steroids!

• oral omega 3 may help in senile degeneration

• 1% EDTA for pt with mineral component

• broad spectrum abx if ulcer present

  • if corneal surface is very irregular, diamond burr keratotomy ‘

focal corneal edema 

• rule out epithelial defect

• confirmed by fluorescein stain uptake 

• treating the ulcer will resolve the edema! 

• if stain is negative, its endothelial disease 

diffuse corneal edema

• endothelial disease

• fluorescein stain, if postive, does not correlate to region of edema

• severe edema can lead to corneal bullae

treatment of corneal edema

• treat underlying disorder if present

• topical NaCl solutions or ointments if bullae present - 5%

• conjunctival Gunderson graft- provides blood vessels which will draw fluid from cornea, reduces edema and limits progression, mnimized risk of bullae

• thermokeratoplasy- salvage procedure, thermal burns to create scar tissue

feline corneal diseases 

• herpetic keratitis (Keratoconjunctivitis)

• eosinophilic keratitis 

• corneal sequestrum 

treatment herpetic keratosis

• limit stress

• famciclovir for at least 3-4 weeks

• cidofovir/gandclovir if orals not possible

• topical antibiotics if ulcerated, avoid neomycin

• avoid steroids

• lysine does not work

• recurrences common

treatment for eosinophilic keratitis

• topical steroids 3-4x/day

• ± systemic steroids for severe cases

• cyclosporine/megestrol acetate BID for maintenance, may not be enough for severe cases

• consider antivirals

• topical antibiotics if ulcers are presen

• lifelong treatment

corneal sequestrum 

• degeneration of the collagen of the corneal stroma 

• caused by chronic irritation, commonly conformation, FeHV-1 

• becomes underminded by vasculature and inflammatory cells 

corneal sequestrum treatment options

• artificial tear lubricants as conservative, risk of unnoticed progression/rupture

• topical antibiotics if infiltrate develops

• surgical removal safest- indicated in painful cases or infections

surgical treatment options for corneal sequestrum

• lamellar keratectomy

• lamellar keratoplasty graft

• conjunctival graf

• corneoconjunctival transposition

• penetrating keratoplasty via corneal donor

common underlying causes of corneal ulcers 

• trichiasis 

• ectopic cillia 

• KCS 

• foreign body 

• trauma 

  • entropion 

simple corneal ulcer and reatment

• superficial, sterile, short healing course

• supportive treatment

• broad spectrum prophylactic antibiotics TID (triple, fluoroquinolones, erythromycin)

• atropine drops q24 for pain

• CONE

• recheck 3-4d

anti-biotic therapy for complex corneal ulcers

• TARGETTED

• broad spectrum and bactericidal = triple antibiotic or fluorquinolone

• rods on cytology = ciprofloxaxin, ofloxacin, moxifloxacin, aminoglycoside

• progression despite therapy = consider multi agent therapy

multi-agent therapy for complex corneal ulcers 

• ciprofloxacin or other fluoroquinolones combined with: 

• cefazolin in saline or artificial tears (keep in fridge, 10 days)

• Tobramycin or gentamicin/amikacin- add IV for total of 9mg/ml 

• separate all drops 5 mn 

cat scratch/lacerations

• elongated laceration- clong and curvilinear, one entry point superiorly

• commonly full thickness so check fibrin/iris seal and distortion, hyphema, shallow AC

• needs surgical repair in >1mm

• lens involvement is common, consider cataract surgery

serum or plasma for treating melting corneal ulcers

• contains macroglobulins that inhibiti proteases activity

• homologous or heterologous

• q2-4hrs

• keep sterile and refrigeraed

• use until edges of ulcer are well defined

• recommended for all infected ulcers

deep corneal ulcers 

• >50% stromal loss 

• consider referral 

• likely need mechanical support such as partial thickness corneal graft, conjunctival graft

• clear in the center = likely a descemetocele- limit handling and invasive procedures, topicals 

non healing indolent ulcers

• superficial, non infected persisent epithelial defect

• surrounding halo of stain uptake

• middle age to older dogs and horses

• topical anibioics 3-4x/day

debridement of indolent ulcers

• apply proparacaine

• clean ocular surface with dilute iodine solution

• peel away the losse epithelial sheet with dry sterile cotton tip

• normal epithelium will not be removed

grid keratotomy 

• following CTA debridement 

• lightly impact the superficial stroma 

• 25g needle 

• keep tip arallel to the corneal surface 

• lines barely visible 

• if you feel a chatter, youre too deep 

diamond burr keratoomy

• polishing of the anterior stroma

• similar to a grid but affects more of the anterior stroma

• always CTA debridement first

• 90% success rate

other ancillary therapies for non-healing ulcers

• E-collar

• oral pain medications

• 5% NaCL to reduce corneal edema and encourage epithelial adhesion

• sodium hyaluronate

• contact lens placement

• serum is controversial

common mistakes with indolent ulcers 

• not debriding 

• debriding an infected or deep ulcer due to misdiagnosis/misunderstanding mechanism 

• not applying eye protection 

• inappropriate cleaning of a diamond burr tip 

simple corneal ulcers in horses

• prophylactic abx q6-8 - neopolygram, terramycin, fluoroquinolones

• prophylactic antifungal q6-8- miconazole, SSC

• mydriatic + cycloplegic q24-atropine

• FLunixin meglumine q12

infected corneal ulcers treatment in horses

• aggressive q2-4 treatment with abx (chloramphenicol or fluoroquinolones) and antifungals (voriconazole, natamycin, luliconazole, miconazole)

• modified if needed based on culture

• appropriate antimicrobials can rapidly sterilize corneal ulcers but the large numbers of neutrophils present can result in progressive stroma lysis in absence of significant infection

best antifungal for keratomycosis 

vorixonazole 

treatment keratomalacia in horses

• anticollagenolytics (serum, plasma, acetylcysteine or EDTA q2-4)

• DO NOT PULL

• create 1% EDTA solution by adding 0.5mL steril water in 3mL EDTA vacutainer

principles for treating stromal abscess

• need medications that can cross intact epithelium

• treated empirically for fungal and bacterial since we cant test

• very slow to resolve medically, 12 weeks

• surgery often recommended

• can lose the eye secondary to uveitis

medical management of stromal abscessation horses 

• topical broad spectrum abx- chloramphenicol, ofloxacin 

• topical antifungals- voriconazole, luliconazole, miconazole 

• topical atropine no more than BID

• systemic NSAID- flunixin meglumine 

• can rupure in the AC or outwards 

use of systemics for stromal abscessation

• antifungals = voriconazole PO q12 effective for both Fusarium and Aspergillus, fluconazole not, minimal 2 week course

• abx- corneal penetration unknown or minimal, may be enhanced if corneal vascularization and intraocular inflammation are present

stroma abscessation surgery

• often required- conjunctival graft, corneal graft

• poor candidates= large lesions, multifocal lesions

immune mediated keratitis in horses 

• chronic, non-ulcerative corneal disease 

• caused by an aberrant immune response directed against cornea 

• often underdiagnosed due to subtle early signs 

• environmental factors like UV light 

• epithelial, stromal, endothelial 

treatment of immune mediated keratitiis

• topical corticosteroids

• topical cyclosporine or tacrolimus maintenance

• fly masks/UV protection

• surgery in refractory cases - keratectomy, implants, PDT

herpetic keratitis in horses

• multifocal punctate lesions

• fluorescein variable

• due to EHV 2 or 4

• Cidofovir BID

• lubrication 2-3x/day

• limit stress

treatment of corneal SCC horses 

• superficial keratecomy 

• enucleation 

• 5FluoroUrocil 

• Strontium 

• cryotherapy 

• remember locally invasive and low met 

goals for subpalpebral lavage systems (SPLs) in horses

• facilitates frequent administration of topical medications

• ensures medications successfully reach ocular surface

• emplyed in dorsal or ventral palpebral fornix

• solutions only!

SPL nerve blocks

• alpha agonists combined with butorphanol as boluses- Detomidine and butorphanol

• auriculopalpebral block 2mL/site

• supraorbital block 2mL/site

• local infiltration around affected area

• mepivacaine 20mg//mL or lidocaine

how o replace an SPL line wihout rep perforating eyelid 

• cut line short 

• feed a lopped 2-0 nylon suture through tube until visualized on ocular surface 

• pull out old broken line

• hook the new line through the suture loop

final considerations for treating equine ocular disease

• appropriate eye mask (hard plastic eye cup, hard plastic shield) always recomended

• CORTICOSTEROIDS by all routes is CONTRAINDICATED for active corneal infections- can potentiate abscessation and delay healing