Lecture 3 2/4/25 Flashcards
How does a foreign body of the eye present?
-bump on cornea if foreign body is imbedded
-may be lodged behind third eyelid
What is the treatment for an ocular foreign body?
-topical anesthesia and hydropulsion
-removal with fine forceps
-cut over the foreign body to retrieve it when imbedded
What is keratoconjunctivitis sicca?
disease resulting in keratitis, conjunctivitis, and often corneal ulceration due to a lack of aqueous tear production
How is keratoconjunctivitis sicca diagnosed?
schirmer tear test
What are the characteristics of superficial ulcers?
-relatively flat corneal surface
-difficult to see without fluoroscein stain
What are the signs of superficial ulcers?
-blepharospasm
-epiphora
-discharge
-pain
-conjunctival hyperemia
What is the treatment for superficial ulcers?
-triple antibiotic
-atropine
What are the characteristics of stromal ulcers?
-ulcer that extends into the stroma
-forms a divot that makes corneal contour uneven
-can extend into superficial, middle, or deep stroma
-often infected
-gelatinous appearance
-may have a continuous inciting cause
-treatment depends on infection, melting, and predisposing cause
What are the characteristics of descemetoceles?
-very deep ulcers that extend through the stroma to descemet’s membrane
-walls of descemetocele will take up stain while floor of ulcer will not
-requires conjunctival graft surgery
What are the characteristics of perforation/iris prolapse?
-occurs with trauma or worsening of deep ulcer that causes a hole to develop in the cornea
-hole becomes plugged with fibrin or iris
-may see aqueous leakage during fluorescein staining
-should always be cultured and have surgery
What is a facet?
“divot” in the corneal stroma that has an intact overlying epithelium; occurs when keratocytes need more time to fill a stromal defect
When are facets of concern?
when the facet is so deep that the cornea is significantly thinned and weakened
What is the etiology of melting ulcers?
-stromal ulcer is complicated by the release of matrix metalloproteinases (MMPs) that cause rapid progressive stromal dissolution
-stroma is rapidly degraded and appears soft/malacic
How are melting ulcers combatted?
topical serum
Where do MMPs come from?
-cornea
-invading leukocytes
-microorganisms
Why are steroids strictly contraindicated in cases of corneal ulceration?
topical and systemic corticosteroids can stimulate otherwise latent MMPs and lead to worsening of an ulcer
What are the etiologies for ulcers with stromal loss?
-bacterial infection
-fungal infection
-chronic unrelenting irritation
What are the characteristics of ulcers resulting from bacterial infection?
-infiltrate indicates infection
-typically Pseudomonas, Strep, or Staph
-must scrape for cytology and culture
-complete a cytology in house to have a fast answer regarding best treatment
What are the characteristics of ulcers resulting from fungal infection?
-rare in small animals
-may appear brown in color
-identified based on cytology and culture; will see hyphae
-treat with antifungals
What are the characteristics of ulcers resulting from chronic unrelenting irritation?
-not necessarily infected
-require complete exam, cytology, and culture and sensitivity
-can be secondary to KCS, entropion, foreign body, or ectopic cilia
What are the medical treatment steps for deep ulcers?
-antibiotics Q2H based on cytology and culture for 24 hrs
-serum Q2H for 24 hrs
-atropine to effect; typically Q6H
-e-collar to prevent further damage
-tapering on antibiotics and serum after 24 hrs
What is a conjunctival graft?
surgical procedure in which a strip of bulbar conjunctiva is sutured over the corneal ulcer; typically a descemetocele or iris prolapse
What is the purpose of a conjunctival graft?
-provides structural support to compromised cornea to prevent perforation
-provides fibroblasts that will strengthen the wound
-provides blood supply and serum to the ulcer
What is the downside to a conjunctival graft?
it will leave a blind spot in the vision where applied
What is the salvage procedure for ulcer treatment?
enucleation
What is an indolent ulcer?
chronic, non-healing, superficial ulcer with a loose edge of epithelium
What causes the pathology of an indolent ulcer?
lack of functional hemidesmosomes
Which breeds have a predilection towards indolent ulcers?
-boxers
-older golden retrievers
How does an indolent ulcer appear in a clinical setting?
-fluorescein stain will migrate under loose epithelial edge
-no sign of infection, such as infiltrate or deepening of the ulcer
When using multiple topicals, in which order should they be applied?
least to most viscous
What are the steps to indolent ulcer treatment?
-debridement with a dry cotton swab following topical anesthetic
-grid keratotomy OR diamond burr debridement
-antibiotics
-recheck after 2 weeks and a repeat debridement and grid/burr
What are some additional therapy options for indolent ulcers?
-contact lens to protect newly formed epithelium
-Remend corneal ulcer repair gel
-topical morphine sulfate eye drops
-cyanoacrylate
-e-collar
-lamellar keratectomy or conjunctival pedicle graft if not healing
What are the characteristics of corneal lacerations?
-caused by trauma
-lacerations less than 1/2 thickness of the cornea can be treated medically like an ulcer
-lacerations greater than 2/3 thickness require primary closure
-lens perforation may necessitate lens or globe removal
