Ocular disease module 2

Coloboma

Notch, hole, or fissure in an ocular structure due to congenital malformation or acquired process

Coloboma embryologic cause

Incomplete closure of the embryonic (choroid) fissure

Coloboma laterality

May be unilateral or bilateral

Classical coloboma shape

Keyhole-shaped defect

Coloboma Greek origin

“Koloboma” meaning mutilated or curtailed

Coloboma timing

Hole present from birth due to failed fissure closure in prenatal development

Coloboma prevalence

Relatively uncommon; affects <1 in 10,000 births

Lens coloboma

Anomaly of lens shape from failure of fetal fissure closure

Lens coloboma primary defect

Defect of zonules and ciliary body development (not true lens tissue defect)

Lens coloboma mechanism

Zonule/ciliary body fails to develop → released tension → segmental lens contraction (notch)

Lens coloboma typical location

Usually inferior nasal quadrant

Lens coloboma truth value

Not a true coloboma of the lens itself

Lens coloboma association

May accompany other ocular defects or systemic disorders

Lens coloboma symptoms

Often asymptomatic; incidentally diagnosed

Lens coloboma best visualization

Best seen in a dilated eye

Lens coloboma clinical sign

Flattening of lens equator in area lacking zonular fibers

Lens coloboma refractive care

Correct refractive error with spectacles

Lens coloboma surgery indication

Consider lens extraction with IOL if severe and not correctable with refraction to prevent amblyopia

Lens coloboma surgical option

Removal of defective lens with IOL in capsular bag + capsular tension ring

Lens coloboma alternate IOL position

IOL may be positioned in the ciliary sulcus

Lens coloboma overall treatment

Surgical treatment required for visual improvement

Lens coloboma OS example

Nasal side lens deficiency (piece of lens absent)

Ectopia lentis

Displacement of the crystalline lens from its normal position

Luxated lens definition

Completely dislocated outside patellar fossa: in AC, free in vitreous, or on the retina (aphakic pupil)

Subluxated lens definition

Partially displaced lens that remains within the lens space

Ectopia lentis usual position

Usually superotemporal; may occur in any meridian

Ectopia lentis inheritance

May be hereditary or acquired

Ectopia lentis acquired cause

Trauma

Ectopia lentis acquired cause

Large eye (high myopia, buphthalmos)

Ectopia lentis acquired cause

Anterior uveal tumors

Ectopia lentis acquired cause

Hypermature cataract

Ectopia lentis et pupillae

Eccentric pupils displaced opposite the direction of lens dislocation

Ectopia lentis et pupillae genetics

Usually bilateral and typically autosomal recessive

Ectopia lentis et pupillae iris finding

Atrophic irides with transillumination defects on slit lamp

Ectopia lentis clinical sign

Red, painful eye (often secondary to trauma)

Ectopia lentis visual impact

Decreased distance acuity from astigmatism or myopia

Ectopia lentis near vision

Poor near vision due to loss of accommodative power

Ectopia lentis symptom

Monocular diplopia

Ectopia lentis without trauma

Suspect hereditary systemic disease or associated ocular disorders

Primary ocular disorders linked to ectopia lentis

Congenital glaucoma or buphthalmos

Primary ocular disorders linked to ectopia lentis

Pseudoexfoliation syndrome

Primary ocular disorders linked to ectopia lentis

Syphilis or chronic uveitis

Primary ocular disorders linked to ectopia lentis

Retinitis pigmentosa

Primary ocular disorders linked to ectopia lentis

Megalocornea

Primary ocular disorders linked to ectopia lentis

Aniridia

Primary ocular disorders linked to ectopia lentis

Hypermature cataract

Primary ocular disorders linked to ectopia lentis

Intraocular tumor

Primary ocular disorders linked to ectopia lentis

High myopia

Systemic diseases with ectopia lentis

Marfan syndrome

Systemic diseases with ectopia lentis

Homocystinuria

Systemic diseases with ectopia lentis

Weill–Marchesani syndrome

Marfan syndrome frequency

Most common cause of heritable ectopia lentis

Marfan ocular prevalence

Ectopia lentis occurs in ~75% of Marfan patients

Marfan pathophysiology

Heritable connective tissue disorder affecting support structures

Marfan ocular feature

Upward lens subluxation (zonule usually intact)

Marfan ocular feature

Retinal detachment risk (lattice degeneration and axial myopia)

Marfan ocular feature

Angle anomaly and glaucoma

Marfan ocular feature

Cornea plana (increased globe dimensions)

Marfan ocular feature

Blue sclera (thinned collagen, increased transparency revealing uvea)

Homocystinuria frequency

Second most common heritable cause of ectopia lentis

Homocystinuria inheritance

Autosomal recessive

Homocystinuria enzyme deficit

Near absence of cystathionine β‑synthase

Homocystinuria mechanism

Decreased zonular integrity due to enzymatic defect

Homocystinuria ectopia rate

Lens dislocation occurs in ~90% of patients

Homocystinuria laterality

Lens dislocation usually bilateral

Homocystinuria displacement direction

~60% inferior or nasal dislocation

Homocystinuria systemic association

Intellectual disability

Homocystinuria systemic association

Osteoporosis

Homocystinuria systemic association

Chest deformities

Homocystinuria systemic association

Increased risk of thrombotic episodes

Homocystinuria refractive effect

Lenticular myopia

Homocystinuria complication

Amblyopia

Homocystinuria complication

Uveitis

Homocystinuria complication

Glaucoma

Homocystinuria complication

Retinal detachment (most serious consequence of a dislocated lens)

Glaucoma mechanisms in ectopia lentis with homocystinuria

• Pupillary block

• Phacoanaphylaxis/phacolytic from ruptured or degenerative capsule → TM blockage

• Post‑traumatic angle recession

• Poorly developed angle structures

• Lens displaced into the anterior chamber

Weill–Marchesani syndrome hallmark

Rare; short stature, brachydactyly, joint stiffness

Weill–Marchesani ocular abnormality

• Ectopia lentis

• Glaucoma

• Severe myopia

• Microspherophakia

Weill–Marchesani ocular features

• Microspherophakia (small spherical lens)

• Usually anterior lens subluxation

• Angle anomaly and glaucoma

Weill–Marchesani systemic feature

• Short stature

• Mental handicap

• Short stubby fingers (brachydactyly)

Weill–Marchesani management

• Spectacles to correct astigmatism from lens tilt/edge effect

• Aphakic correction may yield good vision if visual axis is significantly aphakic

Indication for lensectomy (Weill–Marchesani)

• Lens‑induced glaucoma

• Lens in anterior chamber touching corneal endothelium

• Mature or hypermature lens opacity

• Lens‑induced uveitis

• Imminent complete luxation of the lens

• Retinal detachment