Introduction
Background
Traumatic cataracts occur secondary to blunt or penetrating ocular trauma. Infrared energy (glass-blower's cataract), electric shock, and ionizing radiation are other rare causes of traumatic cataracts.
Cataracts caused by blunt trauma classically form stellate- or rosette-shaped posterior axial opacities that may be stable or progressive, whereas penetrating trauma with disruption of lens capsule forms cortical changes that may remain focal if small or may progress rapidly to total cortical opacification.
Lens dislocation and subluxation are found commonly in conjunction with traumatic cataract. Other associated complications include phacolytic, phacomorphic, pupillary block, and angle-recession glaucoma; phacoanaphylactic uveitis; retinal detachment; choroidal rupture; hyphema; retrobulbar hemorrhage; traumatic optic neuropathy; and globe rupture. Traumatic cataract can present many medical and surgical challenges to the ophthalmologist. Careful examination and a management plan can simplify these difficult cases and provide the best possible outcome.
Pathophysiology
Blunt trauma is responsible for coup and contrecoup ocular injury. Coup is the mechanism of direct impact. It is responsible for Vossius ring (imprinted iris pigment) sometimes found on the anterior lens capsule following blunt injury. Contrecoup refers to distant injury caused by shockwaves traveling along the line of concussion.
When the anterior surface of the eye is struck bluntly, there is a rapid anterior-posterior shortening accompanied by equatorial expansion. This equatorial stretching can disrupt the lens capsule, zonules, or both. Combination of coup, contrecoup, and equatorial expansion is responsible for formation of traumatic cataract following blunt ocular injury.
Penetrating trauma that directly compromises the lens capsule leads to cortical opacification at the site of injury. If the rent is sufficiently large, the entire lens rapidly opacifies, but when small, cortical cataract can seal itself off and remain localized.
Frequency
United States
Approximately 2.5 million eye injuries occur annually in the US. It is estimated that approximately 4-5% of a comprehensive ophthalmologist's patients are seen secondary to ocular injury. Traumatic cataract may present as an acute, subacute, or late sequela of ocular trauma.
Mortality/Morbidity
- Trauma is the leading cause of monocular blindness in people younger than 45 years.
- Approximately 50,000 people are left unable to read newsprint annually as a result of ocular trauma.
- Only 85% patients who experience anterior segment injury reach a final visual acuity of 20/40 or better; while, only 40% patients with posterior segment injury reach this level.
Sex
Male-to-female ratio in cases of ocular trauma is 4:1.
Age
- Work- and sports-related eye injuries most commonly occur in young adults and children.
- Between 1985-1991, a National Eye Trauma System study reported a median age of 28 years in 648 assault-related cases.
Clinical
History
- Mechanism of injury - Sharp versus blunt
- Past ocular history - Previous eye surgery, glaucoma, retinal detachment, diabetic eye disease
- Past medical history - Diabetes, sickle cell, Marfan syndrome, homocystinuria, hyperlysinemia, sulfate oxidase deficiency
- Visual complaints
- Decreased vision - Cataract, lens subluxation, lens dislocation, ruptured globe, traumatic optic neuropathy, vitreous hemorrhage, retinal detachment
- Monocular diplopia - Lens subluxation with partial phakic and aphakic vision
- Binocular diplopia - Traumatic nerve palsy, orbital fracture
- Pain - Glaucoma secondary to hyphema, pupillary block, or lens particles; retrobulbar hemorrhage; iritis
Physical
- Complete ophthalmic examination (defer in case of globe compromise)
- Vision and pupils - Presence of afferent pupillary defect (APD) indicative of traumatic optic neuropathy
- Extraocular motility - Orbital fractures or traumatic nerve palsy
- Intraocular pressure - Secondary glaucoma, retrobulbar hemorrhage
- Anterior chamber - Hyphema, iritis, shallow chamber, iridodonesis, angle recession
- Lens - Subluxation, dislocation, capsular integrity (anterior and posterior), cataract (extent and type), swelling, phacodonesis
- Vitreous - Presence or absence of hemorrhage, posterior vitreous detachment
- Fundus - Retinal detachment, choroidal rupture, commotio retinae, preretinal hemorrhage, intraretinal hemorrhage, subretinal hemorrhage, optic nerve pallor, optic nerve avulsion
Causes
Traumatic cataracts occur secondary to blunt or penetrating ocular trauma.
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References
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Further Reading
Keywords
traumatic cataracts, ocular trauma, blunt trauma, vision loss, visual deficit
