8 - Cornea2

Question 1

List names for EBMD

Answer 1

Map-dot
Fingerprint
ABMD
Cogan’s microcystic dystophy

Question 2

Corneal dystrophies

• anterior
• stromal
• endo

Answer 2

A: EBMD, Reis-Buckler, Meesman

S: macular, granular, lattice, schnyder

E: Fuch’s, PPMD

Question 3

EBMD

• who
• pathophys

Answer 3

Most common ant corneal dyst
AD, slightly more common in females

EXCESSIVE BASEMENT MEMBRANE production -> maturing epi cells become trapped beneath basement membr

Question 4

EBMD

-signs/symp

Answer 4

Signs: negative staining - best seen with retro

Symp: typically asymptomatic + not progressive; vision loss, pain, or photophobia from central corneal changes or RCEs

Question 5

Meesman’s dystrophy

• who
• signs/symp

Answer 5

Rare, AD, 1st year of life

Signs: extensive (hundreds), bilateral, clear INTRAEPITHELIAL cysts - diffusely spread across entire cornea (esp intrapalpebral)

Symp: often asymptomatic
-may occur from ruptured cysts or RCEs (both unlikely before mid-age)

Question 6

Reis-Buckler dystrophy

• who
• pathophys

Answer 6

Rare, AD, early in life

Abnormal development + replacement of BOWMANS LAYER with collagen

Question 7

Reis-Buckler dystrophy

-signs/symp

Answer 7

Signs: bilateral, symmetric, SUB-EPITHELIAL GRAY reticular opacities, most concentrated in central cornea, opacities get worse with age

Symp: PAINFUL episodes from RCEs, fewer episodes with age

Question 8

Macular dystrophy

• who
• signs/symp

Answer 8

Rare, AR***
LEAST COMMON, MOST SEVERE stromal dystrophy
-affects VA much earlier

Signs: diffuse, superficial, central stromal haze between 3-9yo
-progression: diffuse stromal opacification, thinning, MUCOPOLYSACCHARIDE DEPOSITS (gray-white opacities with irreg borders, present in all layers)

Symp: progressive vision loss - severe by age 20-30, episodes of irritation + photophobia secondary to RCEs

Question 9

Granular dystrophy

• who
• signs/symp

Answer 9

AD, 1st decade, no vision loss until mid-age

HYALINE DEPOSITS (small snowflake granules in central stroma)
-eventually spread toward epi + deep stroma, becoming confluent -> decr vision
RCEs are rare

Question 10

Avellino dystrophy

Answer 10

aka granular-lattice dystophy
Rare variant of granular dystrophy
Granular + lattice-like deposits in central stroma

Question 11

Lattice dystrophy

• who
• signs/symp

Answer 11

AD

AMYLOID DEPOSITS: anterior stromal haze with branching, refractile, lattice-like lines
Decr VA in 3rd decade from significant corneal scarring/haze
RCEs are common

Question 12

TGFB1 gene

Answer 12

Granular, Lattice, and Avellino dystrophies result as a mutation of it

Transforming Growth Factor Beta 1(aka BIGH3) gene

Question 13

Schnyder’s dystrophy

• who
• pathophys
• signs/symp

Answer 13

Very rare AD dystrophy

Strong assoc with HYPERLIPIDEMIA, XANTHELASMA, corneal arcus

FINE YELLOW-WHITE RING OF STROMAL CRYSTALS with CENTRAL STROMAL HAZE
Typically asymptomatic + non-progressive

Question 14

Fuchs endothelial dystrophy

• who
• pathophys

Answer 14

AD, females, 60yo (postmenopausal)
30% have positive family hx

DESCEMET’S posterior lamina is produced in EXCESS -> guttata (clumps) of basement membrane with associated DECR IN ENDO CELL DENSITY
-Fuchs is an absolute contraindication for cataract surgery

Question 15

Dystrophies with too much (2)

Answer 15

EBMD = too much basement membrane

Fuchs = too much descemets

Question 16

Fuchs endothelial dystrophy

-signs/symp

Answer 16

Signs: often apparent early (30-40’s), DECR ENDO CELL DENSITY assoc with pleomorphism (change in shape) + polymegathism (change in size)
-guttata have “beaten metal” app + thick pachymetry findings
-primary concern: STROMAL EDEMA due to pumps no longer maintaining proper osmotic balance (endo cells <500 cells/mm^2) -> spills over into epi = PAINFUL BULLAE and scarring
—problems with endo -> stroma -> epi

Symp: asymptomatic until later (50-60’s), progression to blurred hazy vision that’s WORSE IN THE MORNING with pain and glare

Question 17

Endothelial cell counts

• birth/children
• age 80
• when we’re concerned/problems occur

Answer 17

3,000 cells/mm^2

1,000-2,000

<500
(“minimum 400-700 required to prevent corneal edema”)

Question 18

Posterior polymorphous dystrophy

• who
• signs/symp

Answer 18

AD, occurs 2nd-3rd decade, although may manifest as a cloudy cornea at birth (rare)

Signs: bilateral, asymmetric findings at level of descemet’s + endo

• subtle patches of “STUCK ON” VESICLES (hallmark), band lesions (TRAIN TRACK LESIONS), and diffuse opacities
• severe cases: corneal edema and bullae -> painful vision loss

Symp: slowly or non-progressive, most ASYMPTOMATIC; decr vision secondary to edema is most common symptom

Question 19

Posterior polymorphous dystrophy

-pathophys

Answer 19

Metaplasia of endo cells => epithelial-like endothelim

-potential to spread over iris + angle -> seconday angle-closure glauc (15%) from PAS

Question 20

Megalocornea

• who
• what
• associated issues + conditions

Answer 20

Rare, X-LINKED, males

Bilateral, horiz diameter 13+mm
Likely HIGHLY MYOPIC with steep corneas, good vision with correction

Stretching of ocular tissue -> lens subluxation, angle abnorm
Marfan’s, Ehlers-Danlos, Osteogenesis Imperfecta

Question 21

Microcornea

• who
• what

Answer 21

Very rare AD or AR, uni or bilateral

Horiz diam <10mm
Usually HYPEROPIC, at risk for angle-closure glaucoma due to shallow anterior chamber

Question 22

Cornea plana

• who
• pathophys
• signs

Answer 22

Rare, AD or AR

Corneal curvature = scleral curvature
ASSOCIATIONS: sclerocornea*, microcornea
*80% of sclerocornea cases are assoc with cornea plana; results from bilateral scleralizaton (opacification + vascularization) of cornea

Bilateral flat corneas <38D, often as low as 20-30D
Hyperopia, shallow anterior chamber, incr risk angle closure glaucoma (same as microcornea)

Question 23

Aniridia

• who
• ocular manifestations

Answer 23

Rare, bilateral, AD

Corneal lesions (opacity, microcornea, pannus)
Lenticular changes (ct, subluxation)
Posterior seg abnorm (glaucoma 75%, foveal/disc hypoplasia, choroidal coloboma)

Question 24

Haab’s striae

• who
• what

Answer 24

CONGENITAL GLAUCOMA

Horizontal cracks in descemet’s from incr IOP
vs vertical cracks from forceps birth

Question 25

Axenfeld-Rieger syndrome | -characteristics

Answer 25

Continuum of disorders Anterior seg developmental abnormalities that affect the AC angle ~50% develop glaucoma

Question 26

Axenfeld-Rieger syndrome | -signs/symp

Answer 26

Posterior embryotoxin: anteriorly displaced Schwalbe’s -up to 15% of normal eyes, no incr risk for glauc Axenfeld anomaly: PE + angle abnorm (prominent iris processes) -incr glauc risk Reiger anomaly: AA + iris stromal abnorm (corectopia, hypoplasia -> holes in iris tissue (polycoria)) Reiger syndrome: RA + systemic abnorm (mental retardation, dental/craniofacial/genitourinary/skeletal abnorm)

Question 27

Peter’s anomaly

Answer 27

``` Rare Born with central white corneal opacities (leukoma) with iris adhesions 80% bilateral 50-70% develop glauc May develop corneal edema, cataracts ```