3.7 cornea Flashcards
Causes of Dellen?
poor fitting GP lens
pterygia
bleb
tumor
cause of exposure keratopathy?
CN VII issue or lid issue causing incomplete lid closure
CN 7 - bells palsy, CVA, aneurysm, MS, HSV, HSZ
orbicular issue - surgery leading to ectropion, TED, lagnopthalmos, FES
what are symptoms that patient experiences with exposure keratopathy?
symptoms worse in the morning
what are signs of exposure keratopathy?
SPK -> ulcer
decreased sensitivity
causes of filamentary keratitis? What is the.most common?
chronic irritation -> dry eye
** most common cause KCS
FES, SLK, CLS, PKP, erosions, neurotrophic keratopathy
what are the filaments made from in filamentary keratitis?
degenerated epithelial cells and mucous
*** stain with NAFL
What is thygeson’s ? how long does it take to resolve. Who?
bilateral intraepithelial central crumb-like lesions that are raised that occur due to an unknown cause in 20-30 yo
exacerbations - can last 1-2 months if not treated
remissions
can take 10-20 years to resolve
what causes neurotrophic keratopathy?
- damage to V1, VII
surgery - cut V1- lasik, maxillary repair, etc
chronic corneal injury - cls, corneal
dystrophies
systemic disease - HSV,HSZ, DM
meds: timolol, betaxolol, diclofenac sodium
How does V1 affect the cornea?
regeneration, healing, nociceptors for pain
decreased sensitivity
reflex blinking
How can damage to CN 7 cause neurotropic keratitis
decreased reflex tearing
what things can affect CN 7?
bells
tumor
surgery - acoustic neuroma removal
MA
CVA
MS
HSV/HSZ
signs of neurotrophic keratitis
decreased sensitivity
SPK -> ulcer - > can lead to perforation b/c non-healing
no inflammation
what is the pathophys of RCE?
poor hemidesmosome attachment
to basement membrane
secondary to trauma, corneal dystrophies, thickening of BM with age
causes of UV/ thermal keratopathy?
sun exposure
welding
skiing
using a sun-lamp
high UVc - open K+ channels -> loss of intracellular K+ -> cell death
what layers absorb what wavelength of light in the cornea?
tear meniscus height normal
0.2 mm or greater
aqueous deficient testing
schirmer 1 - no anesthetic (basal, reflex, emotional )
- normal > 10 mm in 5 mins , < 5 mm = abnormal
schirmir 2 - only basal
normal > 5 mm in 5 mins
phenol red
> 10 mm in 15 seconds normal
evaporative testing
TBUT < 10 seconds abnormal
rose bengal vs lissamine green
dead and devitalized conjunctival and corneal cells, as well as cells that have lost their mucous covering
Tear hyperosmolarity
abnormal > 308, or difference > 8 most/L
types of aqueous deficient dry eye
- Sjögren’s Syndrome Dry Eye
- primary
- secondary - Non-Sjögren’s Syndrome Dry Eye
- gland attacked
- block ducts
- cut nerves
Sjögren’s Syndrome Dry Eye categories
primary - dry eye, dry mouth
secondary - dry eye, dry mouth + CT disorder (RA>SLE, polyartertis, granulomatosis w/ polyangititis
most common rheumatic disorder?
RA
second - Sjögren’s
attacked gland dry eye cause
sarcoid
lymphoma
aids
graft vs host disease
blocked gland dry eye causes
OBSTUCTION Of lacrimal gland ducts
- trachoma
- pemphigoid
- Erythema multiform
- burns
cut nerves dry eye
cls
DM
bells
drugs
NK
infection - HSV/HSZ
surgery
extrinsic causes of dry eye
vitamin a deficiency
topical anesthetics
cls wear
intrinsic causes
lid pathology or dynamics
low blink rate (parking sons, concentration)
lid position disorders (TED, lagopthalmos)
MGD, bleh
why does vitamin A cause dry eye?
- essential for goblet cell and glycocalyx development.
- result in aqueous tear-deficient dry eye as a result of lacrimal gland acinar damage
- Bitot’s spots on the conjunctiva
What are corneal ecstasies?
keratoconus
pellucid
keratoglobus
what do all the corneal ecstasies lead to?
hydros -> break in descemets
keratoconus cause
- 13% AD inheritance
- most sporadic
- starts in puberty
- MMPs -> damage Bowmans causing collagen 1 fibril displacement -> loss of adhesion b/w fibrils -> thinning and profusion
keratoconus associated conditions
- ocular allergic: ocularallegic: VKC, AKS, FES
ocular K-dystrophies: Fuch’s, PPMD, granular, lattice “finger grinding leads to protrusion”
ocular hereditary: RP, lebers, ROP, Anaridia, cone dystrophy
systemic: T-DOME (turners, down, osteogenesis imperfect, marfans , Ehler danlos + atopic dermatitis , mitral valve prolapse
early and later signs of KCN
early: scissoring reflex, irregular keratometry miers Fleischer’s ring, inferior topo steepening
late: Vogt’s striae (stromal vertical lines, go away with pressure), munson’s sign, Rizuti’s sign ( conical refection on nasal cornea when shine light temporally), hydrops
Pellucid cause
What does it lead to
collagen abnormality
leads to protrusion above area of thinning! and ATR astigmatism
severity of KCN based on K values
mild < 48D
mod 48-54
severe > 54
who gets pellucid
20-40s
pellucid vs KCN
- ≠ KCN: (-) cone, Fleischer’s ring, Vogt’s striae
keratoglobus
who gets it?
Associated conditions?
- birth AR inheritance
or get it from advanced keratopathy (KCN), trauma, exophthalmos
associated with Ehler’s-danlos and Leber;s
what is keratoglobus
diffuse thinning in the periphery occurs at birth AR inheritance
What do all corneal dystrophies have in common?
AD
bilateral
(-) neo
if anterior/stromal -> RCE
if stromal/ posterior -> KCN
Cogan’s microcytic dystrophy names
EBMD
ABMD
Map dot finger print
Cogan’s microcytic dystrophy
who. gets it?
AD, females > males
** most common anterior corneal dystrophy
what causes EBMD?
complications
excessive BM production -> mature corneal cells trapped under BM
-RCE (Usually asymptomatic until get this)
- 10% of ABMD - RCE
- 50% RCE = ABMD
Meesmans
” multiple cysts”
AD condition that affects epithelium in 1st year of life
- 100s of bilateral intraepithelial cysts across entire cornea
can lead to RCE
Reis- Buckler who? What?
AD occurs early in life - 4/5tears old
- Bowmans layer is replaced with Collagen -> PAIN (RCE) -> decrease with time , but opacities worse with age
grey reticular opacities in central cornea look like “ Reeces pieces”
stromal corneal dystrophies
- macular
- granular
- Avellino
- Lattice
- Schnyder’s
” Marilyn Monroe got hers in LA”
all lead to RCE
macular dystrophy
think “Mac daddy”- AR!!!!!
(least common, most severe ie affect vision early by 30 years old)
diffuse strömal haze (3-9 years old) leads to stromal opacification , stromal thinning, and multiple grey/white opacities in all layers of the cornea everywhere
RCE***
what are the macular dystrophies opacities?
mucopolysaccarhide deposits
granular dystrophy
start getting by age 10, vision loss at 60
snowflake granules (hyaline deposits in central stroma) spread to epi and deep stroma
- become confluent and decrease VA
- rarely get RCE
Avellino dystrophy
variant of granular dystrophy
has both granular like and lattice - like deposits in the central cornea
lattice dystrophy
AD stromal dystrophy
amyloid deposits
Anterior stromal haze with
branching, refractile lattice lines. Decreased va by 30s because of stromal haze and scarring
RCE
What stromal dystrophies have a mutation in the TGFB1 gene?
granular
lattice
avellino
Posterior corneal dystrophies
Fuchs
Posterior polymorphous dystrophy
Fuchs
Who?
Symptoms?
Causes?
Complications?
What can worsen it?
30% hereditary
Post menopausal
Posterior polymorphous dystrophy
Who
Symptoms
Signs
Complications
20-50 or see hazy cornea at birth
Symptoms: decreased vision secondary to edema , most asymptomatic , bilateral
Complications: Bullae, corneal edema
Endothelial cell count normal/abnormal
Congenital anterior segment anomalies
Megalocornea
Microcornea
Cornea plana
Anaridia
Haab striae
Axonfield reiger syndrome
Peters Anomaly
Limbal dermoid
Forceps injury
Megalocornea
Who
X linked - males
Bilateral corneal diameter > or equal to 13 mm
High myopes with steep cornea - have good VA with correction
Can be associated with lens subluxation and angle abnormalities -> glaucoma because of stretching of the tissue
- associated with CT disorders - think TDOME
Microcornea
Cornea plana
Corneal curvature = scleral curvature
- flat corneas < 38 D , hyperopia, shallow AC, increased risk of angle closure glaucoma
Associations : sclerocornea/ Microcornea
Sclerocornea
Haab striae vs forceps injury
Axenfield reiger syndrome
Angle Anomolies = prominent iris processes to level of PE - can obscure SS
