Oc Bio

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Microcornea

Back 1

< 10 mm
 Otherwise normal-sized globe
 Nonprogressive, unilateral or bilateral
 Usually flat cornea
 Many associated ocular and systemic conditions
Microcornea
Proposed causes
 Arrest in growth of cornea
 Begins after 5th gestational month when differentiation is complete
 Overgrowth of anterior lips of optic cup

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Sclerocornea

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 Non-progressive, limbus not well-defined
 Occur alone or with other ocular defects
 Usually bilateral, commonly asymmetric
 Abnormality of 2nd wave of mesenchyme
Sclerocornea
 Disordered 2nd wave of mesenchyme
 Delay or aberration in induction of growth of one portion of eye will affect another
 Absence of limbal mesenchymal tissue (limbal anlage) affects:
 Limbal differentiation
 Scleral and corneal differentiation
 Corneal curvature to exceed scleral
Sclerocornea
 Corneas are flat (≤ 43 D)
 Cornea plana
 Corneal curvature ≤ scleral curvature
 Proposed to be same entity

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Posterior Keratoconus

Back 3

 Rare
 No relationship to anterior keratoconus
 Most common
 Localized crater-like lesions in central or eccentric posterior cornea
 Abnormal retinoscopic reflex

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Keratoglobus

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 Bilateral, noninflammatory
 Entire cornea thinned
 Keratometry: 60-70D
 Strong association with Ehler-Danlos syndrome (type VI)

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STUMPED

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Corneal clouding

Sclerocornea
Tears in Descement
Ulcers
Metabolic conditions
Posterior issues: posterior keretaconus and Peter’s
Endothelial dystrophy
Dermoid

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Posterior Keterconus

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 Rare
 No relationship to anterior keratoconus
 Most common
 Localized crater-like lesions in central or eccentric posterior cornea
 Abnormal retinoscopic reflex
Keratoglobus
 Bilateral, noninflammatory
 Entire cornea thinned
 Keratometry: 60-70D
 Strong association with Ehler-Danlos syndrome (type VI)
Posterior Corneal Defect
(Peters’ Anomaly)
Posterior Corneal Defect
(Peters’ Anomaly)
 Rare, sporadic & frequently bilateral disorder
 Range of severity, from barely detectable focal indentation to total corneal scarring and ectasia.
 Peter’s anomaly results from:
 Delay or failure of separation of the lens vesicle from the surface ectoderm
Posterior Corneal Defect
(Peters’ Anomaly)
 Results in an adhesion between the cornea and lens
 Migration of mesenchyme is impeded by this adhesion, causing the characteristic features of this anomaly
Peters’ Anomaly

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Axenfeld-Rieger Syndrome

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Axenfeld-Rieger Syndrome
 Almost always bilateral
 Typically associated with family history
 Present at birth
Axenfeld-Rieger Syndrome
Clinical findings
 Posterior embryotoxon
 Prominent Schwalbe’s line
 Can also be seen in normal eyes
Axenfeld-Rieger Syndrome
Clinical findings
 Prominent iris processes
 Iris hypoplasia
 Corectopia
 Polycoria
 Glaucoma – 50%

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 Haab striae:

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 “circumferential” breaks
Neonatal corneal opacities associated with systemic metabolic diseases

Front 9

Lysosomal Storage Disease

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Lysosomal Storage Disease: Histopathology
 Storage of excess GAGs or glycolipids as membrane bound vacuoles in keratocytes
 Vacuoles distend keratocytes
 Visible with the slit lamp as fine punctate opacities (corneal clouding)
Lysosomal Storage Disease:
 Fine punctate dots & diffuse gray haze in the stroma
 Normal epithelium & endothelium
 Bilateral & symmetric clouding

 Rarely present at birth
 Presents in first years of life
 Becomes denser over first 2 decades

Front 10

Epithelial-Basement Membrane Dystrophy (EBMD)
Cogan’s Microcystic Dystrophy

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Epithelial-Basement Membrane Dystrophy (EBMD); Cogan’s Microcystic Dystrophy
 Most common of the anterior corneal dystrophies
 Onset – age 30-40 yrs old
 Usually central
EBMD (slit lamp)
 Maps = gray epithelial patches; islands of anomalous basement membrane
 Dots = multiple intraepithelial cysts + cellular debris; intraepithelial opacities

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Fingerprints

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Fingerprints = gray or refractile fine lines; basement membrane separating sheets of duplicated epithelium
EBMD
 Synthesis of abnormal basement membrane
 Reduplication and intraepithelial segments of basement membrane
 Clinical sequellae

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Stromal Dystrophies

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Stromal Dystrophies
 Abnormal substances appears within keratocytes or among collagen fibrils

 Granular (hyaline)
 Lattice (amyloid)
 Macular (GAGs)

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Granular dystrophy (hyaline deposits)

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Granular dystrophy (hyaline deposits)
 Hyaline deposits in anterior stroma
 Gray-white opacities do not extend to limbus
 Visual loss relatively late in life

Front 14

Macular dystrophy

Back 14

Macular dystrophy (GAGs deposits)
 Least common, but most severe clinically
 Begins as central gray-white superficial stromal opacities
 Born with clear corneas that begin to cloud between 3-9 years of age
 Autosomal recessive
 Accumulation of GAGs

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Lattice dystrophy

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Lattice dystrophy (amyloid deposits)
 Most common of stromal dystrophies
 A primary localized corneal amyloidosis
 Glasslike branching lines in the stroma, seen best with retroillumination
 Autosomal dominant

Front 16

Fuch’s endothelial dystrophy

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 Thickening of Descemet’s membrane (corneal guttata).
 Compromise of endothelial function
 Corneal edema
 Rare to become symptomatic before age 50
 As disease progresses, corneal decompensation
 Marked stromal edema
 Microcystic and bullous epithelial edema
 Subepithelial fibrosis


Fuch’s Dystrophy
 Corneal decompensation
 Marked stromal edema
 Microcystic and bullous epithelial edema
 Subepithelial fibrosis

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Anterior Keratoconus (Ectatic Dystrophy)

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 Progressive thinning (ectasia) of central stroma
 Imparts a conical configuration to cornea
 Usually presents around puberty
 Bilateral, central and slowly progressive (characteristics of a dystrophy)
Clinical Signs:
 Munson’s sign
 Fleisher’s ring (iron) in deep epithlium & basement membrane at base of cone
 Vogt’s lines (vertical striae / stress lines)
 Stromal thinning
 Acute hydrops (stromal edema)
 Scissors reflex (retinoscopy)

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Pathologic Myopia:
Posterior staphyloma

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Posterior staphyloma
Abnormal sclera has a low mechanical resistance
Stretches in response to:
Intraocular pressure
Extraocular muscle tensions

> 25 mm = pathologic myopia

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acute conjunctival inflammation is hyperemia

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The most conspicuous clinical sign of acute conjunctival inflammation is hyperemia, which because it is due to dilation of the posterior conjunctival vessels, is most marked in the fornix and bulbar conjunctiva and diminishes toward the limbus

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iridodialysis

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tear in the iris root due to trauma

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Fuch’s Heterochromic
Iridocyclitis:

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young, middle-aged adults
Cataract
KP’s flare & cell
Glaucoma
(hyperemia, pain,
photophobia limited)

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iridocyclitis

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)
The clinical findings include:
Flare: excess protein in the aqueous
Cell: presence of inflammatory cells in the aqueous

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Grunert

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Grunert’s spur: @ iris root

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Von Michael's

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Von Michel’s spur: periphery of the
sphincter

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fuch's Spur

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Fuch’s Spur: midway along the length
of the sphincter

Front 26

Epicapsular stars

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Remnants of the ATVL
Deposits on the anterior capsule of the lens
Does not affect acuity
Can have a few – upper photo or many – lower photo

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Aniridia

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Rare Condition – Autosomal dominant bilateral
Cause
Rim of optic cup fails to proliferate over the anterior surface of the lens
Just a “stump” of iris with stroma and abnormal pigment epithelium at the edge of the lens

Front 28

Typical Iris Coloboma

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inferior closure doesnt happen

Front 29

Microcoria

Back 29

Abnormality of the dilator muscle
Congenitally small pupil that is less than .5mm
Usually inherited
Failure of last phase of
Iris differentiation
Due to malformation of the dilator muscle

Front 30

Ectopic pupil

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not centered

Caused by ectopic lentis lAbnormal persistence of ATVL lIris grows less readily in one quadrant lResults in myopia and poor image quality that is difficult to treat

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Congenital Iris Cysts

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Small evaginations of epithelial layers as iris is forming lSeen as bulges in the iris stroma lUsually only noted on lultrasound lUsually benign and rarely interfere with aqueous flow

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The posterior part of the iris epithelium is continuous with

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the nonpigmented epithelium of the ciliary body

Front 33

The most important mechanism involved in maintaining the cornea in a dehydrated state?

Back 33

Bicarbonate pump