Corneal Ectasias & Degenerations

corneal ectasia

a thinning & bulging of the cornea

keratoconus

• genetic link & associated with several systemic conditions, environmental factors

• progressive, noninflammatory, bilateral ectatic corneal disease

• characterized by focal thinning & weakening that leads to corneal distortion

• onset: 2nd-6th decade

  • earlier onset correlated w/ more severe disease

• signs/sx:

  • irregular astigmatism

  • myopia

  • corneal scarring

  • gradually decreasing visual clarity accompanied by ghosting/doubling of images

  • glare, halos, photophobia

  • itching, irritation

  • eye strain

  • eye pain

  • scissoring ret reflex

  • Fleischer rings

  • striae

  • focal thinning of cornea

Fleischer ring

iron deposition at base of cone in keratoconus due to sharp change in curvature of the cornea

striae

micro-creases in posterior cornea due to stretching of the corneal tissue seen in keratoconus

hydrops

rupture of endothelium due to severe thinning seen in keratoconus, corneal edema, AC rxn common, takes months to resolve

steep central Ks, superior to inferior asymmetry, astigmatism >1.5D, skewed radial axes >21deg

describe the classic keratoconic corneal topography

corneal tomography, provides true elevation of anterior & posterior cornea, corneal thickness, & corneal curvature

what is the best tool for detecting keratoconus early on and what information does it tell us?

keratoglobus

• rare, bilateral, globular configuration of the cornea which can resemble keratoconus w/ the exception that the cornea is diffusely, uniformly thinned, particularly in the periphery

• onset: at birth

• signs/sx:

  • myopia

  • astigmatism

• rupture of globe can easily occur and patients must be cautioned to avoid trauma

• associated with systemic collagen disorders

pellucid marginal degeneration

• rare

• characterized by inferior corneal thinning & corneal ectasia above the area of thinning

  • thinned area is usually confined to circumferential band-shaped area inside inferior limbus (4:00-8:00)

  • protrusion above the area of thinning

• painless, bilateral, asymmetric

• signs/sx:

  • significant ATR & irregular astigmatism

  • “crab claw” corneal maps

  • “beer belly” cornea

• tx:

  • CL, surgery

corneal arcus senilis

• involutional, common, age related

• etiology: deposition of cholesterol, triglycerides, & phospholipids in peripheral stromal cornea

  • may be associated with abnormalities in blood lipids

  • unilateral suggestions vascular occlusion on side w/o arcus

  • most often age related (universal by 8th decade)

• appearance:

  • complete/incomplete (inferior first, then superior, then circumferential)

  • yellow-white, perilimbal hazy opacity

  • clear perilimbal zone

  • lipid first noted in Descemet’s membrane, then Bowman’s layer

corneal farinata

• involutional, common, age related

• etiology:

  • AD

  • manifestation of senile changes

• appearance:

  • gray-white, small, dustlike dots & flecks deep in the stroma or pre-Descemet’s zone

  • no vascularization

  • axially diffuse or annular distribution

  • flour like appearance

  • visually insignificant

furrow degeneration

• involutional, common, age related

• etiology:

  • age

• appearance:

  • painless, thinning of cornea

  • in area b/t arcus senilus & limbus

  • no tendency to perforate

  • no vascularization

  • may see a scalloped arcus margin

Hassall-Henle bodies

• involutional, common, age related

• etiology:

  • age

• appearance:

  • peripheral, localized, nodular thickening of Descemet’s membrane

  • looks the same as corneal guttata but peripheral

  • small, circular, dark areas w/in normal endothelial mosaic on specular reflection

anterior crocodile shagreen

• involutional, common, age related

• bilateral, polygonal, grayish-white opacities separated by clear tissue in deep areas of epithelium & Bowman’s

• typically located axially

• vision not usually affected

• looks like scales

• most prominent centrally

posterior crocodile shagreen

• involutional, common, age related

• bilateral

• grayish-white opacities in deep stroma & Descemet’s

• appear as small, polygonal patches of various sizes separated by dark regions

white limbal girdle of vogt

• involutional, common, age related

• etiology:

  • age, found commonly in patients over 45yo

• appearance:

  • white, narrow, crescentic, irregular, chalky opacity

  • in temporal & medial limbal areas of Bowman’s

  • nasal greater than temporal in interpalpebral zone

  • no vascularization

  • vision unaffected

  • arc shape

  • may/may not have a clear interval

  • may resemble early band keratopathy

early calcific band keratopathy (type 1)

• lucid interval

• fine crystals

• swiss cheese holes

• sightly more superficial

• rather smooth central edge

• calcium

• calcium-adjacent conjunctiva

true Vogt’s girdle (type 2)

• no lucid interval

• chalklike flecks

• no “holes”

• slightly deeper

• thornlike extensions from central edge

• elastosis

• pinguecula-adjacent conjunctiva

amyloid degeneration

• non-involutional, uncommon

• bilateral, innocuous degenerative condition usually seen after age 50 if going to appear

• appearance:

  • polymorphic, refractile, punctate, comma-shaped & filamentous amyloid deposits throughout stroma

  • most prominent centrally & posteriorly

  • best seen in retroillumination

  • small, salmon pink to yellow-white central, raised, fleshy, waxy masses w/ a nodular surfac eon the cornea & conjunctiva

  • may be vascularized

• patients are asymptomatic

band keratopathy

• non-involutional, uncommon

• etiology:

  • calcium salts depositing in anterior stroma & Bowman’s layer

  • occur from localized ocular inflammatory disease (chronic uveitis, silicone oil in AC, or systemic diseases causing hypercalcemia)

  • most are idiopathic

• appearance:

  • deposits in interpalpebral fissure of BM/Bowman’s membrane

  • lucid interval

  • Swiss cheese appearance (holes represent areas where small nerves penetrate)

• tx:

  • topical lubricants

  • bandage CL

  • EDTA & anesthetic plus scraping (chelation)

  • phototherapeutic keratectomy

  • lamellar keratoplasty

• can reoccur

lipid degeneration

• non-involutional, uncommon

• etiology:

  • primary or secondary problem as a result of local or systemic disease, trauma, & after severe corneal disease

• appearance:

  • dense, yellow-white opacity that may fan out with feathery edges from blood vessels in the affected corneal area

• tx:

  • control underlying disease

  • argon laser or needle point cautery to feeder vessels

  • penetrating keratoplasty

Salzmann’s nodular degeneration

• non-involutional, uncommon

• etiology:

  • chronic inflammation

  • most common comorbidities: MGD, CL wear, peripheral corneal vascularization, pterygium, keratoconjunctivitis, exposure keratitis

• appearance:

  • discrete, elevated, bluish-white superficial stromal opacities

  • raised nodules

  • usually arranged in circular fashion around pupil area

  • often appear w/in or adjacent to an area of previous scarring, occur over old scars

• can lead to poor TF wetting, dellen, irregular astigmatism, discomfort, & poor vision if on visual axis

• tx:

  • none

  • scraping

  • superficial keratectomy

  • lamellar keratoplasty or excimer

  • CLs

spheroidal degeneration

• non-involutional, uncommon

• etiology:

  • related to geographic or climactic conditions or previous inflammation

  • males who have worked outdoors

• appearance:

  • bilateral, spherical, translucent, golden-brown oily droplets under epithelium or conjunctiva at 3 & 9:00

  • may also be noted central, superficial stroma in a band shape, often in interpalpebral zones

  • proteinaceous deposits

  • fluoresce brightly in UV

• tx:

  • usually none unless progressive & causing visual impairment, then superficial/lamellar keratectomy or corneal transplant

  • protection from UV

Terrien’s marginal degeneration

• non-involutional, uncommon

• etiology:

  • unknown

  • usually in younger males, often after 4th decade

• appearance:

  • slowly progressive, marginal thinning, bilateral

  • non-inflammatory

  • gradual development over years

  • can cause significant irregular/ATR astigmatism

  • marginal opacification

  • superficial vascularization

  • thinning of corneal stroma margin, beginning superonasally, spread circumferentially

  • early punctate stromal opacities

  • advancing edge exhibits lipid deposition

  • epithelium intact

  • corneal perforation possible

  • may look like early arcus

  • may develop pseudopterygia

• tx:

  • if perforation is threatened or if astigmatism is severe, then reconstructive full thickness or lamellar corneal graft

  • scleral GPCL

Mooren’s ulcer

• rare

• etiology:

  • unknown

  • immune component to stromal antigens, possibly triggered by injury

  • benign form often seen unilaterally in older, white, female patients, better response to tx

  • more severe form often seen in young males, bilateral, & poor response to tx, more common in blacks & Indian origin

• appearance:

  • marginal ulcer

  • severe, painful

  • central & circumferentially progressing

  • inflammation, corneal infiltration

  • epithelial breakdown

  • perforation can occur

• tx:

  • no well established tx

  • topical & systemic steroids

  • immunosuppressants

  • lamellar graft if perforation occurs (often unsuccessful)

Mooren’s ulcer

• unilateral or bilateral

• pain & inflammation

• epithelial breakdown at central edge of active ulcers, stains w/ NaFl

• spreads centrally & circumferentially

• slow or rapid progression

• overhanging central edge

• can become vascularized w/ healing

• no lipid

• can cause corneal melting & destruction

• perforation occurs in severe cases

Terrien’s marginal degeneration

• usually symmetric & bilateral

• usually painless & not inflamed

• epithelium intact, no NaFl staining

• spreads circumferentially

• slow progression

• gradual central edge

• vascularized base

• lipid deposits

• usually main problem is astigmatism caused by ectasia

• perforation occurs in 15% of cases as a result of minor trauma

keratoconus

scissoring (keratoconus)

striae (keratoconus)

Fleischer rings (keratoconus)

corneal scarring (keratoconus)

focal thinning (keratoconus)

Fleischer ring (keratoconus)

Fleischer ring (keratoconus)

striae (keratoconus)

striae (keratoconus)

striae (keratoconus)

corneal scarring (keratoconus)

corneal scarring (keratoconus)

corneal scarring (keratoconus)

hydrops (keratoconus)

keratoconus

keratoconus

keratoconus

keratoglobus

pellucid marginal degeneration

pellucid marginal degeneration

pellucid marginal degeneration

pellucid marginal degeneration

corneal arcus senilis

corneal arcus senilis

corneal arcus senilis

corneal farinata

furrow degeneration

Hassall-Henle bodies

anterior crocodile shagreen

anterior crocodile shagreen

posterior crocodile shagreen

white limbal girdle of vogt

white limbal girdle of vogt

white limbal girdle of vogt

white limbal girdle of vogt

amyloid degeneration

amyloid degeneration

band keratopathy

band keratopathy

band keratopathy

band keratopathy

band keratopathy

band keratopathy

band keratopathy

lipid degeneration

lipid degeneration

lipid degeneration

Salzmann’s nodular degeneration

Salzmann’s nodular degeneration

Salzmann’s nodular degeneration

Salzmann’s nodular degeneration

spheroidal degeneration

spheroidal degeneration

spheroidal degeneration

spheroidal degeneration

Terrien’s marginal degeneration

Terrien’s marginal degeneration

Terrien’s marginal degeneration

Terrien’s marginal degeneration

Mooren’s ulcer

Mooren’s ulcer

Mooren’s ulcer

Mooren’s ulcer