7 - Ant Seg Cornea

Question 1

Megalocornea

Answer 1

Non-progressive enlarged cornea
>/= 13mm

Rare, congenital, usually males

XL, AR, or AD
-will be assoc with something/doesn’t occur in isolation

Late assoc with glaucoma, cataracts

Lubrication for exposure keratitis

Question 2

Microcornea

Answer 2

Clear, normal thickness
<9mm newborn, <10mm after 2yrs

AR or AD

Normal globe dimensions

Accompanied with other abnormalities - cataracts, coloboma, cornea plana (flat K), PFV, Ehler-Danlos

Question 3

Microphthalmos

Answer 3

Small, malformed eye
Diseased

Isolated or with syndromes

Question 4

Nanopthalmos

Answer 4

Normal small eye (e.g. high hyperopia)

Shallow AC (AACG possible)

Question 5

Keratoconus

Answer 5

Central/paracenral K bulges, progressive thinning

Presents and progresses into puberty

Hereditary
-down syndrome, atopic disease, chronic eye rubbing

Vogt striae (iron, stress lines) and apical scarring (unlike keratoglobus)
Tears in Descemet’s -> hydrops

Question 6

Ketaoglobus

Answer 6

Bilateral, non-inflamm thinning of entire K

Present at birth, rare, AR

Steep curvature + thinning in periphery, deep AC

Spontaneous breaks in Descemet’s -> acute edema

K rupture with minor blunt trauma (protective eyewear, scleral CLS)

Question 7

Keratoconus vs globus

• etiology
• onset
• location of thinning
• location of protrusion

Answer 7

etiology: both unknown
onset: C puberty, G birth
thinning: C para/central, G generalized
protrusion: C apical, G generalized

Question 8

Keratoconus vs globus

• scarring
• clinical presentation
• signs
• topography

Answer 8

scarring: C present, G absent

presentation:

• C: unilateral, red VA (myop, astig), acute hydrops
• G: rupture with mild trauma, very rarely acute hydrops

signs:

• C: conical ectasia, oil drop red reflex, “scissoring” reflex, vogt striae, munson’s sign, fleishers ring
• G: globular ectasia

topography:

• C: irreg astig, asymmetric bowtie, skewed radial axis
• G: generalized steepening

Question 9

Posterior embryotoxin

Answer 9

Aka Prominent Schwalbe’s line

Thickening and anterior displacement of schwalbe’s

Irregular white line ant to limbus, visible on SLE

Isolated finding (10-15% pop) or with Axenfeld-Rieger

Question 10

Peters anomaly

Answer 10

Aka iridocorneal adhesions

Posterior K defect with an overlying stromal opactity with iris strands

• touching cornea from behind
• could be the adhesion of the lens to the K

Size/density of opacity ranges
Strands to the defect vary in number, density

Central opacity could get vascularized and protrude

Seen in different diseases, incl Axenfeld-Rieger

Question 11

Epibulbar/limbal dermoid

• describe
• onset
• contents
• location and size

Answer 11

Fibrofatty tissue covered with epithelium

Present at birth, very little growth after

Could contain ANYTHING - hair follicles, sebaceous/sweat glands, nails

Straddles limbus, could be up to 10mm diameter
Could extend to corneal stroma and adjacent sclera
Mainly inferior limbus

Question 12

Epibulbar/limbal dermoid

• concerns
• tx

Answer 12

Can induce astig -> amblyopia

Removal for ocular irritation, amblyopia risk
Excision can lead to scarring, astigmatism, amblyopia (i.e. can be worse than before)

Question 13

Sclerocornea

Answer 13

Total corneal opacification, resembles sclera

Difficult to see limbus

Central K clearer than periphery

Often seen in kids with systemic problems with short lifespan