Fig. 21.1
Traumatic cataracts complicated with lens capsule rupture induced by open-globe injury. (a) Open-globe injury results in lens anterior capsule rupture and localized cortical opacity. A 7-year-old boy was stabbed in the right eye by a sharp blade 3 days previously. A 2 mm-long, self-sealed, full-thickness wound was observed in the mid-periphery of the temporal cornea. A long oval-shaped anterior capsule rupture was seen in the mid-peripheral region of the superior temporal lens, with exudative membrane adhering to the margin of the rupture and a localized opacity in the superior temporal lens. (b) Open-globe injury results in lens capsule rupture and cortex leakage. The right eye of a 6-year-old boy was injured by a metal wire 2 days before. The anterior chamber was shallow, with varying depths between the upper and lower parts of the anterior chamber. There was anterior capsule rupture, lens opacities, swelling, and loose cortex, part of which leaked into the anterior chamber. (c) Open-globe injury resulting in membranous cataract. A rural 12-year-old boy’s left eye was injured by bamboo fragments 9 months previously. Because both his parents were migrant workers, he was left untreated after the injury. The image shows posterior iris synechia in the inferior nasal quadrant, pupillary distortion, extensive organization of the lens capsule, and partial absorption of the lens materials
Without proper and timely treatment, traumatic cataracts complicated by capsule rupture may induce secondary glaucoma, uveitis, and many other complications. The lens expansion caused by capsule rupture may lead to narrowing of the anterior chamber and pupillary block, which may induce IOP to increase rapidly. If the lens material prolapses into the anterior chamber, lens particle glaucoma could occur due to the elevated IOP induced by the obstruction of the trabecular meshwork with a large amount of lens cortex particles. It usually occurs several days after the lens capsule ruptures and may present as significant eye pain, redness, and vision loss. Slit-lamp examination may detect white cortex particles and/or capsule debris in the aqueous humor with a positive aqueous flare sign and deposition of loose lens material at the bottom of the anterior chamber as well as posterior iris synechiae. Gonioscopy findings often show an open anterior chamber angle, with large amounts of lens cortex debris adhered to the trabecular meshwork. The histologic examination demonstrates lens particles and macrophages in the aqueous humor. In addition, the exposure of lens proteins following capsule rupture may lead to the development of anterior uveitis. If the inflammation involves the trabecular meshwork, IOP elevation may be induced due to obstruction of aqueous outflow, which is called phacoanaphylactic glaucoma. Its pathognomonic sign is granulomatous inflammation of the lens, but its diagnosis is always difficult. Histology shows extensive lesions of polymorphonuclear cell, lymphocyte, macrophage, and epithelioid cell reactions around the lens cortex, which may help to establish the diagnosis.
If traumatic cataracts complicated by capsule rupture are left untreated for a long time, capsule organization may occur, and the lens material may be absorbed over time. Finally, only the organized capsule and a small amount of cortex are left, and this is defined as membranous cataract (Fig. 21.1c) [5]. It may also occur in patients with other types of traumatic cataracts. We observed that membranous cataract is more common in children with traumatic cataracts than in adults, with increased rigidity of the organized capsule, or even complicated with neovascularization.
Traumatic Cataracts Without Capsule Rupture
This condition is relatively rare in cases of open-globe injury. It may be caused directly by the trauma, but more often by indirect injuries including disruption of eye ball integrity, changes in the intraocular microenvironment, intraocular inflammation, and disturbance to lens metabolism. It may develop slowly after the injury, presenting as varying degrees of lens opacity.
Traumatic Cataracts Complicated by Intraocular Foreign Body
The usual mechanisms of intraocular foreign body-induced traumatic cataract are:
- A.
Mechanical injury by the foreign body: As the foreign body penetrates through the lens capsule, the aqueous humor enters into the cortex causing lens opacity (Fig. 21.2a).
Fig. 21.2
Traumatic cataracts complicated by intraocular foreign body. (a) Lens foreign body. A 10-year-old boy complained of a small “stone” splashing into his left eye 2 days before. There were opacity and swelling of lens cortex and shallowing of the anterior chamber. A brownish black foreign body was seen in the mid-peripheral portion of the superior temporal lens, about 3 mm × 2 mm in size. (b) Siderosis. A 15-year-old boy presented with visual loss in the left eye for half a year. History taking revealed that his left eye was injured by “tiny iron sheets” when modifying a model car 1 year before, but he paid no attention to this. After pupillary dilation, multiple anterior subcapsular brown patches were seen in the mid-peripheral region of the lens, arranged in a circle, with mild lens opacities. A CT scan confirmed metal foreign bodies retained on the retinal surface of the left eye
- B.
Toxic reaction to the foreign body: Even without direct lens injuries, metal foreign bodies (e.g., iron and copper) retained in the eye for a long time may produce various chemical reactions and thereby result in cataracts. Examples include lenticular siderosis (Fig. 21.2b) and chalcosis.
21.1.1.2 Pediatric Cataracts Caused by Closed-Globe Injury
In the scenario of closed-globe injury, blunt forces per se or secondary factors may give rise to traumatic cataracts. Blunt forces on the crystalline lens may lead to capsule rupture, resulting in rapid opacification of the lens. Secondary factors after trauma, such as changes in the intraocular microenvironment, intraocular inflammatory responses, or metabolic disturbance to the lens, might cause slowly progressive lens opacity. Their clinical presentations may vary depending on the direction and intensity of the external force, but usually include a Vossius ring, rosette-shaped cataracts, punctate cataracts, and total cataracts. Besides, patients may have concurrent ocular injuries, such as iridodialysis (Fig. 21.3a), retinal breaks, and anterior chamber/vitreous hemorrhage.
Fig. 21.3
Traumatic cataract caused by ocular contusion. (a) A 15-year-old boy presented 1 month after his right eye received a contusion after impacted with another player’s head while playing basketball. The image shows an iridodialysis from 3 to 8 o’clock and white lens opacity, with the lens dislocated temporally and superiorly and a visible lens equator. (b) Posterior capsule rupture caused by ocular contusion. A 13-year-old girl presented 1 day after her left eye received a contusion after impacted with bicycle handlebars as she fell off. The image shows pupillary dilation, multiple tears at the pupillary margin, oval-shaped posterior capsule rupture, and localized cortical opacity surrounding the posterior capsule rupture. (c) Cataract caused by ocular contusion. A 12-year-old boy was hit with a fist 1 day before. No wound was observed on cornea or sclera. The lens rapidly opacified with cleft formation
Traumatic Cataracts Caused by Closed-Globe Injury and Complicated with Capsule Rupture
When the anterior ocular surface of the eye is hit with a blunt force, rapid anterior-posterior shortening of the eye occurs with simultaneous equatorial expansion. Severe equatorial stretching may result in capsule rupture, typically posterior capsule rupture (Fig. 21.3b). Then, opacities occur as the aqueous humor enters into the lens through the rupture. Hydration of the lens develops soon after opacification at the site of rupture, followed by formation of vacuoles and edema. Opacification would later extend to the periphery of the lens and, eventually, involve the entire lens (Fig. 21.3c). When the capsular rupture is small, however, the opacity may remain localized. Unless examined immediately after trauma, the posterior capsule rupture caused by closed-globe injury is often dormant, which may not be detected during a slit-lamp exam. But Scheimpflug imaging with a Pentacam has been reported to have been used to reveal posterior capsule rupture [6, 7].
Cataracts Caused by Closed-Globe Injury Without Capsule Rupture
- 1.
Vossius ring: It appears as circular opacity in the lens anterior capsule. When the eye receives blunt trauma, the iris pigment epithelial cells at the pupil edge are shed off and imprinted on the surface of the anterior capsule in a circular pattern, which is referred to as a Vossius ring. In this case, anterior subcapsular opacities might occur.
- 2.
Ectopia lentis: Cataracts caused by closed-globe injury are often combined with various degrees of zonular fracture, leading to ectopia lentis (Fig. 21.4a).
Fig. 21.4
Cataracts caused by closed-globe injury without capsule rupture. (a) Traumatic cataract caused by ocular contusion and complicated with ectopia lentis. A 16-year-old boy presented 5 days after being struck in the left eye with a badminton. A moderate degree of white lens opacity with intact lens capsule can be seen. There was zonular fracture from 9 to 1 o’clock, with the lens dislocated temporally and inferiorly. (b) Rosette-shaped lens opacities. A 15-year-old boy presented 7 days after his right eye received a blow with fist while fighting. Clefts can be seen between the lens fibers, arranged in a radial pattern, like rose petals
- 3.
Rosette-shaped cataract: When the lens is impacted by an external force, the structure of lens fibers and sutures may be disrupted, and thereby fluid may flow into the intersutural and interlamellar spaces, forming rosette-shaped radial opacity (Fig. 21.4b). Such cataracts may occur within hours or weeks of an injury, and the opacities may be resolved spontaneously in some patients. In other cases, however, cataract may develop several years after the injury, and the opacity may be permanent.
- 4.
Punctate cataracts: Lots of tiny opaque dots are formed beneath the subepithelial of the lens. They usually develop over a period of time following the injury and remain static and impact vision slightly.
21.1.1.3 Pediatric Cataracts Caused by Other Physical or Chemical Agents
Electric shock, heat, radiation, or chemical injury may also change the structure and transparency of the crystalline lens. Although most of these cataracts are rarely seen in children, electrical injury is relatively common.
Electrical Injury
Electrical injury includes electric shock and lightning strike. Electric shock in children is often caused by inadvertent touching of household appliances or a socket. The severity of an electrical injury depends on several factors such as the duration of contact, the strength of electrical current, the size of contact area, the part of body in contact, and the pathway the electrical current passes through the body. Cataracts caused by lightning strike often present as both anterior and posterior subcapsular opacities, while those caused by electric shock mainly present as anterior subcapsular opacities. Cataracts induced by electrical injury may be static or progressive. It may take several months or even years to form complete clouding of the lens in progressive cases. For a small number of patients, the lens opacities may be completely absorbed and become transparent. If an electrical injury-induced cataract is static and visually insignificant, observation is recommended; otherwise, surgical treatment should be considered. Favorable surgical outcomes can be achieved if not complicated with other ocular tissue injuries.
Chemical Injuries
Chemical-induced cataract is relatively rare in children, but if it occurs it is usually by alkali chemicals, such as lime. As alkali chemicals dissolve fats and proteins, they are more likely to penetrate into the eye causing lens metabolic disturbance directly or indirectly, which leads to various degrees of lens opacity. Milky white opacity of the entire lens may be detected in serious cases.
21.1.2 Traumatic Ectopia Lentis
Traumatic ectopia lentis often occurs following blunt trauma to the eye. A blunt force may cause compression and equatorial expansion of the globe and hence zonular dialysis, resulting in the lens tilting anteriorly or posteriorly. At the site of the dialysis, vitreous prolapse may occur (Fig. 21.5a), often with concurrent traumatic cataracts.
Fig. 21.5
Traumatic ectopia lentis. (a) Traumatic ectopia lentis with vitreous hernia. A 17-year-old boy presented 2 weeks after being hit in his right eye with a tennis ball. Zonular dialysis from 7 to 2 o’clock was seen in the right eye. The lens was displaced inferiorly and nasally, and the vitreous herniated into the anterior chamber through the dislocation area in the superior temporal quadrant (see arrows). The lens is mildly opaque. (b) Traumatic dislocation of the lens into the anterior chamber. A 10-year-old girl presented 2 days after her left eye received a blast injury from a firework during a wedding ceremony. The lens displaced into the anterior chamber, contacted with the corneal endothelium, where mild corneal edema could be seen. The dislocated lens is largely transparent, with the appearance of an oil drop. IOP in the left eye was 45 mmHg. (c) Traumatic dislocation of the lens into the vitreous cavity. A 10-year-old boy presented 3 months after a blow to the right eye with a rock. B-scan ultrasonography revealed the lens dislocated into the vitreous cavity (see arrow)
21.1.2.1 Lens Subluxation
The extent and presentation of lens subluxation may vary with the extent of zonular dialysis. Mild subluxation may be asymptomatic without any signs. A larger extent of lens subluxation is associated with more apparent clinical manifestations: (1) uneven anterior chamber depth (ACD) or changes in ACD (irregular ACD along different meridians in one eye); (2) iridodonesis and/or phacodonesis, a quivering of the iris and/or the lens on eye movement, accompanied with pupil displacement; (3) lens decentration, with a partially visible equatorial region of the lens after pupillary dilation; and (4) vitreous prolapse into the anterior chamber in serious cases.
21.1.2.2 Complete Lens Dislocation
- 1.
Dislocated into the anterior chamber: The lens is typically seen at the pupillary zone, with the transparent lens looking like an oil drop (Fig. 21.5b), and white disc-shaped opacities may also be observed. The dislocated lens may cause corneal endothelial abrasion and Descemet membrane detachment, leading to corneal edema.
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