Cornea Flashcards
___ is seen in alkaptonuria.
Ochronosis is seen in alkaptonuria.
- Alkapton (brown/black material) accumulates in body tissues, e.g. medial, lateral recti, cartilaginous tissues e.g. earlobes, nose, heart valves, tendons.
- Urine turns dark after exposure to air.
What is appropriate adjunctive therapy for perilimbal conjunctival melanoma with suspected corneal epithelial involvement?
Absolute alcohol to adjacent corneal epithelium and scleral base
Corneal epithelial microtrauma resulting from the insertion and removal of soft contact lenses seems to play a role in the etiology of what disorder?
Infectious keratitis
Why is tissue from donors younger than 2 years generally not used in corneal transplantation?
The tissue is steeply curved and flaccid.
In immunocompetent individuals, what is the most common ocular presentation of chronic microsporidial infection? Treatment?
Stromal keratitis; topical fumagillin, PKP if severe stromal thinning
Causative organisms of acute purulent conjunctivitis:
- Subconjunctival hemorrhage
- Chronic with angular blepharitis
- Hyperacute in sexually active adult
Subconjunctival hemorrhage: GNR Haemophilus influensa, GPC Streptococcus pneumoniae
Chronic with angular blepharitis: Gram-neg diplococci Moraxella catarrhalis
Hyperacute: Gram-neg diplococci Neisseria gonorrhoeae
Management of progressive corneal thinning in patient with Mooren ulcer
Limbal conjunctival excision, PKs if descemetocele or perforation
__% of patients with zoster of CN V1 develop ocular involvement. Diminished corneal sensation occurs in up to __% of patients.
70% of patients with zoster of CN V1 develop ocular involvement. Diminished corneal sensation occurs in up to 50% of patients.
Compare and contrast herpes zoster vs herpes simplex keratitis
The ends of herpes zoster dendritiform lesions are typically blunt, have little epithelial ulceration, stain poorly with fluorescein and bengal, and have more raised, plaque-like appearance. Herpes simplex dendritic lesions have terminal bulbs.
Chlamydia serotypes that cause:
- trachoma
- adult and neonatal inclusion conjunctivitis
- lymphogranuloma venereum
Trachoma: A-C
Inclusion conjunctivitis: D-K
Lymphogranuloma venereum: L1, L2, L3
In the US, what is an acceptable donor cornea preservation time for corneal transplantation?
11-14 days
Rate of recurrence of conjunctival melanoma following excision
> 50%
When an inheritance pattern is present in Fuchs endothelial dystrophy, what type of pattern is most common?
Autosomal dominant
What should be done prior to removing sutures for PKs?
Identify steep axis, confirm axis and that astigmatism is regular with refraction and topography
What clinical feature of conjunctival melanoma increases the risk of regional lymph node metastasis?
Involvement of palpebral conjunctiva
Contraindications for corneal tissue transplantation
- Death of unknown cause
- Congenital rubella
- Reye syndrome within the past 3 months
- Neurodegenerative conditions including prion disease (eg, Creutzfeldt-Jakob, PML)
- Infectious conditions (HIV, hepatitis, active bacterial/viral encephalitis or bacterial/fungal endocarditis, suspected rabies or history of being bitten within the past 6 months)
- Down syndrome (PK, DALK)
- Intrinsic eye disease including RB, malignant tumors of the anterior segment, or known adenocarcinoma in the eye of primary or metastatic origin, active ocular or intraocular inflammation, congenital or acquired disorders of the eye that would preclude a successful outcome
- Leukemias
- Active disseminated lymphomas
- High-risk behavior (eg, intravenous drug use or incarceration in prison)
- Prior refractive corneal surgery (except for EK)
**note posterior choroidal melanoma may be considered acceptable
Superior limbic keratoconjunctivitis causes a ___ conjunctival reaction.
Superior limbic keratoconjunctivitis causes a papillary conjunctival reaction.
Diagnosis of seasonal allergic conjunctivitis can be confirmed by finding a predominance of ___ in a conjunctival scraping.
Diagnosis of seasonal allergic conjunctivitis can be confirmed by finding a predominance of eosinophils in a conjunctival scraping.
Characteristics of blepharitis caused by:
- staphylococcus
- seborrheic etiology
- Demodex
Staph: collarettes (hard brittle scales/crusts surrounding individual cilia)
Seborrheic: greasy scales along lashes
Demodex: cylindrical sleeves around lash base
Most common mechanism for vision loss in HZO?
Vasculitis (can lead to optic neuritis)
Long-term treatment of atopic dermatitis and associated keratoconjunctivitis uncontrolled by topical therapies
Oral cyclosporine
What diagnosis should be considered in a young patient with bilateral, rapid-onset non-healing defects with ring infiltrates?
Anesthestic abuse
How does ocular surface squamous cell carcinoma present?
White/yellowish pink lesion near limbus with possible leukoplakia
How does amyloidosis of conjunctiva present?
Waxy yellowish localized lesion
What risks are lower in DALK than PK?
CME, glaucoma, cataract, expulsive hemorrhage, RD, endophthalmitis
Best slit lamp technique for:
- corneal endothelium
- edema
- posterior capsule and corneal opacities
- lesions and corneal foreign bodies
Endothelium: specular reflection
Edema: sclerotic scatter
Posterior capsule and corneal opacities: retroillumination
Lesions and corneal foreign bodies: proximal illumination
How is CMV transmitted?
Sexual contact or through body fluids (saliva, breast milk)
How is VZV transmitted?
Direct contact with skin lesions or respiratory droplets
How are toxoplasmosis and toxocariasis transmitted?
Fecal-oral
What treatment removes lashes for longest duration possible without collateral damage to eyelid?
Radiofrequency ablation/electrolysis
Epilation -> recurs in 3 weeks
Cryotherapy -> causes eyelid margin thinning, loss of adjacent lashes, depigmentation
Preferred suture for surgical repair of the limbus portion of a corneoscleral laceration
10-0 Nylon
Preferred suture for surgical repair of scleral wounds
9-0 Nylon or 8-0 silk
What is the most common anatomical source of infection in microbial scleritis?
Local extension from adjacent cornea, usually Pseudomonas
When treating a corneal alkali burn, oral administration of high-dose ___ ___ may reduce the risk of corneal perforation by acting as a cofactor in collagen synthesis. ___ ___ should be monitored when this therapy is initiated.
When treating a corneal alkali burn, oral administration of high-dose vitamin C (2 g per day) may reduce the risk of corneal perforation by acting as a cofactor in collagen synthesis. Renal function should be monitored when this therapy is initiated.
What slit lamp finding is most suggestive of sterile contact lens-associated keratitis?
Peripheral corneal infiltrates with minimal to no fluorescein uptake
What cardiac condition is associated with keratoconus?
Mitral valve prolapse
Presentation and management of UV-induced keratitis
Eyelid edema, conjunctival hyperemia, diffuse punctate keratitis; treat with topical antibiotic ointment, cycloplegia, and patching to reduce discomfort from eyelid movement
For patient with herpetic epithelial or stromal keratitis, oral acyclovir prophylaxis decreases the risk of recurrence by __%.
For patient with herpetic epithelial or stromal keratitis, oral acyclovir prophylaxis decreases the risk of recurrence by 50%. (HEDS decreased risk from 28% to 14%)
How does iris atrophy differ between VZV and HSV?
VZV sectoral, HSV patchy
What surgical option is recommended for unilateral chemical corneal burn with complete conjunctivalization of the cornea? Bilateral?
Unilateral: simple limbal epithelial transplantation (autograft of limbal epithelium from the fellow eye)
Bilateral: limbal stem cell allograft (living related donor) or keratolimbal allograft (eye bank donor cornea)
Where are Hassall-Henle bodies found? What do they represent?
Peripheral Descemet membrane; overactive hyaline production/excrescences by endothelial cells
Ocular medications that are contraindicated in neurotrophic keratopathy
Topical anesthetics, NSAIDs, beta blockers, CAIs, trifluridine, BAK-containing drops
Impair wound healing
What is appropriate management of ruptured globe with extruded iris tissue and thin translucent membrane adherent to stromal surface?
Reposit prolapsed iris tissue with removal of the membrane (likely epithelialization from cornea or conjunctiva, increases risk of epithelial ingrowth)
What vital dye is most likely to produce symptoms of ocular irritation?
Rose bengal
Most common indication for PK in US and internationally?
Keratoconus, then repeat corneal transplant
Most appropriate treatment of PAM without atypia
Careful follow-up every 6-12 months
Where does HSV remain latent?
Sensory ganglia
How is HSV transmitted?
Contact with oral secretions or infectious fluid from lesions containing virus, usually during childhood
Management of large corneal perforations >2mm?
Corneal patch graft
Mechanism of action of olopatadine
H1-antagonist / mast-cell inhibitor
