Cornea Flashcards
(238 cards)
What are the causes and associations of acute hemorrhagic conjunctivitis?
Causes
• Enterovirus type 70
• Coxsackie A24
• Adenovirus type 11
Associations
• Follicular conjunctivitis
• Subconjunctival hemorrhage
What is the percentage of patients with conjunctival lymphoid tumor that have extraocular lymphoma?
• 20%
• Non-Hodgkin’s B cell
• Most common in > 50 years old or
immunocompromised
What is the inheritance pattern and extraocular malignancies associated with ataxia telangiectasia?
• Autosomal recessive
• Increased risk of breast cancer and T cell leukemia
What biomolecules make up the corneal stroma?
• Type 1, 5, and 6 collagen
• Proteoglycans (dermatan and keratan sulfate) in a
higher ratio posterior than anterior stroma
What is the most common branch of cranial nerve V1 involved in herpes zoster infection?
• V1 frontal branch
What are the causes of enlarged and prominent corneal nerves?
○ Enlarged corneal nerves
• Multiple endocrine neoplasia (MEN) type 2B
• Medullary carcinoma of thyroid gland, pehochromocytoma, mucosal neuromas, marfanoid habitus
• Phytanic acid storage disorder (Refsum disease)
• Leprosy (Hansen disease)
• Familial dysautonomia (Riley-Day syndrome)
• Neurofibromatosis
• Acanthamoeba perineuritis
○ Prominent corneal nerve
• Keratoconus
• Ichthyosis
• Fuch’s corneal dystrophy
• Corneal edema
• Congenital glaucoma
Where do lateral eyelid lymphatics drain?
• Preauricular lymph nodes
Where do medial eyelid and conjunctiva lymphatics drain?
• Submandibular and submental lymph nodes
What is congenital hereditary stromal dystrophy?
• Rare
• Present at birth
• Bilateral opacification of central stroma with white
flakes
• Clear peripherally
• Moderate to severe visual loss
• Non progressive or slowly progressive
• Mutation in decorin gene on chromosome 12”• Rare
• Present at birth
• Bilateral opacification of central stroma with white
flakes
• Clear peripherally
• Moderate to severe visual loss
• Non progressive or slowly progressive
• Mutation in decorin gene on chromosome 12
What is the mutation in macular corneal dystrophy?
• Carbohydrate sulfotransferase 6
What is gelatinous corneal dystrophy?
• Autosomal recessive
• Mutation in tumor associated calcium signal
transducer 2
• Initially resembles band keratopathy
• Eventually lesions resemble “mulberries”
• 100% recurrence rate after PKP
What dystrophies do mutations in TGF beta-1 (5q31) cause?
• Lattice type 1
• Avellino/granular corneal dystrophy 2
• Reis-Bucklers/Thiel Benke
• Granular corneal dystrophy 1
“LARGe” 5 letters, chromosome 5
What is the water content of the cornea?
• 78%
• Maintained by intact epithelium and endothelium
(water pump of endothelial cells)
What is hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease)?
• Autosomal dominant
• Telangiectasias of conjunctiva, nasopharynx, GI, brain,
etc
• Abnormal blood vessels in adulthood results in
bleeding → iron deficiency anemia
• Fragile vessels in conjunctiva can bleed with minimal
eye rubbing
What are the surgical risk factors in posterior polar cataract and Mittendorf dot cataract?
• Risk of posterior capsule breaks
• Avoid hydrodissection, instead perform
hydrodelineation
What does tear osmolarity measure and how is it affected in dry eye?
• Measures aqueous tear deficiency
• Elevated in aqueous tear deficiency (>300 mOsm/L)
• This test is not necessarily diagnostic of dry eye in
isolation
• There can be variable results at the same appointment
• Results should be considered in context of clinical signs
What is tear lactoferrin?
• Made by acinar cells of lacrimal gland
• Binds iron, prevents bacterial growth
• indirect measure of lacrimal gland function
• helps differentiate aqueous tear deficiency from
evaporative dry eye
• This test is not necessarily diagnostic of dry eye in
isolation
• There can be variable results at the same appointment
• Results should be considered in context of clinical signs
How is tear IgE affected in allergic conjunctivitis?
• Elevated in allergic conjunctivitis
What is tear MMP-9 and how is it affected in dry eye?
• Inflammatory cytokine
• Released by epithelial cells in response to stress
(blepharitis)
• Elevated MMP-9 suggest evaporative dry eye
What is the treatment for a gonococcal infection?
• One time intramuscular ceftriaxone 1 g
Or
• One time spectinomycin intramuscular
Or
• Oral fluoroquinolone 5-7 days
Plus
• Eye lavage every hour
Plus
• Treatment for chlamydia (high rate of concurrence) –
azithromycin or doxycycline
What is the treatment for chlamydia?
• Azithromycin 1g (single dose)
Or
• Doxycycline 100 mg BID 7 days
Or
• Erythromycin 500 mg QID x 7 days
What is the basic secretion test?
Measures basal secretion:
• Topical anesthetic
• Blot off excess fluid
• Check at 5 minutes
• <3 mm = abnormal
• 3-10 mm = equivocal
What is the Schirmer I test?
• Do NOT use topical anesthetic
• Measures basic and reflex tears
• Check at 5 minutes
• <5.5mm at 5 mins = abnormal
• >15 mm at 5 mins = epiphora
What is the Schirmer II test?
• Uses topical anesthetic
• Measures reflex secretion
• Nasal mucosa stimulated
• Check at 2 minutes
• <15 mm at 2 mins = abnormal