301 DISLOCATION OF THE LENS

●Isolated ocular disorders are associated with dislocation of the lens.

●Simple ectopia lentis is usually an autosomal dominant entity that may be expressed in the first few years of life in one form and during adulthood in another form (genetic spontaneous late subluxation of the lens). Dislocation is often superotemporal and symmetric.

●Ectopia lentis et pupillae is an autosomal recessive condition that is associated with corectopia. The pupil and the lens are commonly dislocated in opposite directions.

●Other ocular disorders associated with ectopia lentis include retinitis pigmentosa, uveitis, aniridia, and pseudoexfoliation syndrome.

●Dislocation of the entire lens nucleus or of lens fragments can occur during cataract surgery.

COURSE/PROGNOSIS

●Dislocated lenses with intact capsules can be well tolerated for long periods of time without surgical intervention. Resultant refractive errors, glaucoma, and lenses luxated into the anterior chamber may cause the dislocation to become intolerable.

●Dislocated lenses in children can lead to amblyopia.

●In cases of dislocated lens material after cataract surgery, timely pars plana vitrectomy and lensectomy for the removal of the residual lens material to reduce the postoperative complications of inflammation and glaucoma can result in a favorable outcome.

DIAGNOSIS

Clinical signs and symptoms

●Besides decreased vision, patients may complain of monocular diplopia because of the decentered lens. In addition, there may be pain associated with inflammation, photophobia, and elevated intraocular pressure.

●Examination may show progressive myopia or marked astigmatism, iridodonesis, phakodonesis, vitreous in the anterior chamber, pupillary block, iritis, elevated intraocular pressure, as well as obvious dislocation of the lens or lens implant.

PROPHYLAXIS

●Patients should be advised to avoid participation in contact sports as further dislocation of the lens may occur and they are at higher risk for retinal detachments. In children, amblyopia prevention is paramount.

●If the lens is luxated into the vitreous cavity, an aphakic correction may be used.

●Dilation of the pupil or pupilloplasty may be useful in some phakic cases.

●Topical corticosteroids are used to control ocular inflammation in lens dislocation after cataract surgery or trauma. Typically, cycloplegics and anti-glaucoma medications are used in conjunction with the corticosteroids.

●Pupillary block glaucoma from lens dislocation may respond to mydriatics. If this is not successful, laser or surgical peripheral iridectomy should be attempted before lens removal.

●Dislocation of the lens into the anterior chamber often causes corneal edema and pupillary block with elevated intraocular pressure. Dilation of the pupil and digital pressure on the cornea through the lid with the patient in a supine position may relieve the situation by pushing the lens into the vitreous cavity.

Surgical

Indications for surgical intervention

●Visual function is decreased, either due to a cataractous lens or to a clear lens with the edge in the pupillary axis, precluding suitable phakic or aphakic correction.

●A dislocated lens leaks lens protein, leading to a lensinduced uveitis or glaucoma.

●There is irreversible luxation of the lens into the anterior chamber with pupillary block.

Techniques

●Lenses that are only slightly decentered may be approached with careful phacoemulsification. Capsular tension rings may assist implant stability. Some surgeons advocate iris or capsule retractors to decrease lens movement during extraction.

●If the lens is further dislocated with vitreous prolapsed into the anterior chamber, a pars plana approach with vitreoretinal instrumentation for lensectomy and vitrectomy is recommended. Either a sewn-in posterior chamber lens implant or an anterior chamber implant may be used.

●Lens fragments that have fallen posteriorly in the course of cataract extraction should be removed using standard three-port vitrectomy techniques, not via anterior segment approaches. A sub-total anterior vitrectomy with removal of residual anterior lens material and placement of an acrylic intraocular lens implant in the sulcus position should be attempted before the vitreoretinal portion of the surgery. The cataract wound should be closed with suturing.

●If immediate access to a vitreoretinal specialist is not possible, the dropped nucleus or retained fragments may be removed up to 2 weeks later or longer depending on the overall clinical situation.

TREATMENT

Systemic

●Patients with spontaneous dislocation of the lens need evaluation for associated systemic disease. Genetic counseling may be appropriate for specific conditions.

Ocular

●If the subluxated lens is clear, refraction usually can be accomplished satisfactorily.

COMPLICATIONS

●Retinal detachment may be associated with the dislocated lens after trauma, cataract surgery, or pars plana vitrectomy and lensectomy for retained lens material.

●After cataract surgery, the dislocated lens material can be associated with uveitis, leading to cystoid macular edema and glaucoma. In addition, there is the increased risk of endophthalmitis when there is vitreous loss.

lenticonus and by visual deprivation due to cataractous changes. Occlusion therapy must be instituted before or after cataract extraction when amblyopia is present.

Patients with posterior lenticonus have a relatively good visual prognosis because the condition is rarely significant at birth, thus allowing the foveal fixation reflex to develop during the first months of life. In a series of 39 patients, Cheng and colleagues found that 19 patients (49%) achieved postoperative visual acuity of 20/40 or better. In another series by Crouch and Parks, 12 of 21 patients (63%) showed a postoperative visual acuity of 20/50 or better.

Posterior lenticonus is the most prevalent unilateral cataract in a normal-sized eye. Anterior polar cataract, congenital nuclear cataract, and persistent hyperplasia of the primary vitreous occur in microphthalmic eyes with a corneal diameter of 10 mm or less.

Butler TH: Lenticonus posterior. Arch Ophthalmol 3:425–436, 1930.

Cheng KP, Hiles DA, Biglan AW, et al: Management of posterior lenticonus. J Pediatr Ophthalmol Strabismus 28:143–149, 1991.

Crouch ER, Parks MM: Management of posterior lenticonus complicated by unilateral cataract. Am J Ophthalmol 85:503–508, 1978.

Gibbs ML, Jacobs M, Wilkie AOM, et al: Posterior lenticonus: clinical pattern and genetics. J Pediatr Ophthalmol Strabismus 30:171–175, 1993.

Khalil M, Saheb N: Posterior lenticonus. Ophthalmology 91:1429–1430, 1984.

Mohney BG, Parks MM: Acquired posterior lentiglobus. Am J Ophthalmol 120:123–124, 1995.

Pollard ZF: Familial bilateral posterior lenticonus. Arch Ophthalmol 101:1238–1240, 1983.

Simons BD, Flynn HW: A pars plana approach for cataract surgery in posterior lenticonus. Am Ophthalmol 124:695–696, 1997.

TREATMENT

Patients without significant cataractous changes can be followed or treated with dilating eyedrops, correction with glasses, or patching.

Surgical

Common indications for surgical treatment include the following:

●A decrease in visual acuity to a level of 20/70 or less after occlusion therapy;

●The loss of central fixation reflex;

●The onset of ‘sensory’ strabismus.

In these cases, lens extraction via a limbal incision with irriga- tion-aspiration or irrigation-aspiration-cutting instruments is the treatment of choice. A pars plana approach for cataract extraction has also been reported. Intraocular lens implantation is a standard procedure in patients at least 2 years old. Younger patients can be optically corrected with contact lenses. During surgery, the posterior weakened capsule bows anteriorly toward the cornea when the infusion is lowered.

COMMENTS

Posterior lenticonus or lentiglobus must be suspected in patients with unilateral progressive cataracts in normal-sized eyes with cataractous changes in the posterior cortical layer. This disease has a progressive course; it does not usually interfere with the fixation reflex during the first months of life. Surgery must be considered when visual acuity is moderately reduced from optical distortion or cataractous changes.

REFERENCES

Bleik JH,Traboulsi EI, Maumenee IH: Familial posterior lenticonus and microcornea. Arch Ophthalmol 110:1028, 1992.

ETIOLOGY/INCIDENCE

Microspherophakia is the presence of a small and spheric lens. The lens is larger in the anteroposterior diameter, whereas the equatorial diameter is smaller than normal. The decreased equatorial diameter of a microspherophakic lens measures an average of 6.75 to 7 mm (normal, 9.0 mm), and the anteroposterior diameter is larger than normal (>5.0 mm, normal: 3.4 to 4.5 mm). The overall lenticular mass is reduced by approximately 25%. The entire lens can be visualized when the pupil is dilated. The lens curvature is increased, resulting in lenticular myopia. Microspherophakia is commonly associated with subluxed lenses. The zonules in microspherophakia are long and irregular, and some can be seen in a retracted state on the lens surface.

Microspherophakia has been attributed to an arrest of development of the lens in the fifth to sixth month of embryonic life, a time at which the lens is spheric. Anomalies in development of the ciliary body and the zonules and nutritional deficiency from the tunica vasculosa lentis have all been implicated in this arrest of development. A zonular defect with loss of the normal zonular traction on the lens could allow the lens to remain spheric instead of gradually converting to the normal biconvex shape.

Microspherophakia can be inherited as an isolated autosomal dominant or autosomal recessive disorder. A gene for the autosomal recessive form for Weill–Marchesani syndrome has been mapped to chromosome 19p 13.3-p13.2. On a survey of 396 congenital dislocated lenses, fewer than 1% were dislocated secondary to microspherophakia and Weill–Marchesani syndrome.

COURSE/PROGNOSIS

The visual prognosis in microspherophakia is poor due to the development of secondary glaucoma. Repeated episodes of elevated intraocular pressure may result in the formation of peripheral anterior synechiae.

DIAGNOSIS

Differential diagnosis

Microspherophakia is most commonly associated with the Weill–Marchesani syndrome. Patients have brachycephaly, a short body build with brachydactyly, normal or hypertrophic musculature, a broad thorax, hypoextensible joints, and microspherophakia with subluxed lenses. Less commonly, microspherophakia is associated with homocystinuria, ectopia lentis et pupillae, Marfan syndrome, Klinefelter’s syndrome, chondrodysplasia punctata, mandibulofacial dysostosis, and metaphyseal dysplasia.

COMPLICATIONS

Secondary glaucoma

Secondary glaucoma is the most serious complication of microspherophakia. There are two mechanisms involved in this complication.

Pupillary block

There is a forward displacement of the lens with a greater area of iris-lens contact, which causes an increased resistance to the flow of aqueous from the posterior to the anterior chamber. Iris bombé can result from this forward lens displacement. Inverse glaucoma is a term used to describe an acute rise in intraocular pressure after the instillation of miotics. Miotics increase the iris-lens surface contact area, producing a pupillary block. This block can be reversed with pupillary dilation.

Angle-closure glaucoma

The loose zonules permit the lens to move forward and the peripheral iris to bow anteriorly and close an already crowded angle. Gonioscopy usually reveals normal angle structures.

Lens dislocation

Lens dislocation is a common finding. In microspherophakia associated with Weill–Marchesani syndrome, the lens dislocates downward early in life. Less commonly, the lens can dislocate into the anterior chamber after pupillary dilation. In dominant disease with microspherophakia such as Marfan syndrome, the lens moves upward in a majority of cases. Iridodonesis and phacodonesis are usually noticeable on slit-lamp examination.

TREATMENT

Ocular

Glaucoma control is of primary concern. Standard pharmacological glaucoma treatment may not be effective. Mydriatics and cycloplegics, such as cyclopentolate and tropicamide, may be of value in preventing pupillary block glaucoma, but prolonged mydriasis may allow the lens to dislocate into the anterior chamber. In patients with microspherophakia and intact zonules or in whom the zonular integrity is unknown, miotics should never be used to break an attack of acute glaucoma. Hyperosmotic agents and carbonic anhydrase inhibitors that shrink the volume of the vitreous may permit posterior movement of the lens and relief of the pupillary block. A peripheral iridectomy is then usually necessary.

Surgical

Peripheral iridectomy

Laser iridectomy is the initial choice of treatment, after which surgical iridectomy can still be performed if the former fails. Surgical complications such as vitreous loss are more common in these patients due to the lack of vitreous face protection by lens periphery and zonules.

Lens extraction

In patients with severe lenticular myopia, lens subluxation or secondary glaucoma, lens extraction may be necessary in addition to a peripheral iridectomy. Lensectomy with anterior vitrectomy is the treatment of choice in these cases.

REFERENCES

Faivre L, Gorlin RJ, Wirtz MK, et al: In frame fibrillin-1 gene deletion in autosomal dominant Weill-Marchesani syndrome. J Med Genet 40:34– 36, 2003.

Fuchs Josefine, Rosenberg Thomas: Congenital ectopia lentis. A Danish national survey. Acta Ophthalmol Scand 76:20–26, 1998.

Halpert M, BenEzra David: Surgery of the hereditary subluxated lens in children. Ophthalmology 103:681–686, 1996.

Jensen AD, Cross HE, Paton D: Ocular complications in the WeillMarchesani syndrome. Am J Ophthalmol 77:261–269, 1974.

Johnson VP, Grayson M, Christian JC: Dominant microspherophakia. Arch Ophthalmol 85:534–542, 1971.

Myopia

Myopia is lenticular in nature, but superimposed axial myopia has been reported in isolated autosomal dominant microspherophakia. Myopia is usually severe and progressive, beginning in early childhood. It can fluctuate according to the pupil diameter and lens position. It ranges in magnitude from −5 to −30 diopters.

PROPHYLAXIS

Topical mydriatics can be used to control pupillary block glaucoma, but mydriatics may allow the lens to dislocate anteriorly in patients with abnormal zonular attachments. A laser iridectomy can be performed before secondary glaucoma develops.

304 TRAUMATIC CATARACT 366.20

Dan S. Gombos, MD, FACS

Houston, Texas

George M. Gombos, MD, FACS

Brooklyn, New York

Lens opacification is a common complication after ocular trauma. It can be diagnosed at the time of injury or years later and can cause a significant decrease in vision. Distinguishing them from other cataracts (congenital, metabolic, age related) is an essential component in their management. The identification of associated ocular injuries and the anticipation of potential complications are critical to the medical and surgical approach taken by the ophthalmologist.

FIGURE 304.1. Acquired cataract following trauma. Photograph courtesy of Stephen Orlin, MD.

●Contusive injuries may cause a full or partial circle of iris pigment on the anterior surface of the lens capsule (Vossius’ ring).

●There may be signs of trauma to other ocular structures, including the cornea, iris, zonules, and posterior pole: lens subluxation, iridodonesis, phacodonesis, shallow or deep anterior chamber, increased or decreased intraocular pressure and hyphema.

Differential diagnosis

Cataracts from other causes include age-related, metabolic, congenital, and drug-induced cataracts.

PROPHYLAXIS

●Protective shatter-resistant goggles should be worn at work.

●Childhood hazards at home and at playgrounds should be identified.

●Lead shielding should be used during radiation exposure.

perforating injuries to the globe. Nonperforating trauma includes contusive and concussive injuries to the orbit, head, or body.

●Traumatic cataract can occur after electric shock, radiation, or chemical injury.

●Any damage to the lens capsule can lead to cataract formation. Contusion-related injuries result in a pressure wave that may lead to dysfunction of the lens epithelium and edema of cortical lens fibers (Figure 304.1).

COURSE/PROGNOSIS

●Cataract formation (simple traumatic cataract) may be the only significant pathology after an injury. Complicated traumatic cataracts involve perforating injuries with damage to other ocular structures (cornea, iris, cilliary body, vitreous, retina).

●Opacities caused by concussive or contusive injuries may be transient, static, or progressive.

●Sharp objects (needles, pins) that cause perforating injuries can lead to focal nonprogressive lens opacities.

●When the anterior and posterior capsules are both damaged, complete lens opacification commonly occurs. This may progress rapidly, reducing vision to hand motion or light perception within hours.

DIAGNOSIS

●History of trauma.

●Lenticular opacities typical of trauma are identified.

●The form may be discrete, punctate, or rosette-shaped, or there may be scattered subepithelial changes.

●The location is commonly anterior, segmental and subcapsular.

●Late rosette opacities deep in the cortex may be found years later.

required. Periodic reevaluation is suggested.

Surgical

Patients with traumatic cataracts should undergo surgery if the visual acuity deteriorates or there are ocular complications.

●With extensive penetrating or perforating injury, immediate surgical intervention is essential.

●Extracapsular cataract extraction or phacoemulsification is the procedure of choice. Zonular dehiscence must be anticipated.

●If the lens capsule is badly ruptured and the lens material is mixed with vitreous and blood, complete lensectomy and vitrectomy are indicated. Open-sky or pars plana techniques can be used.

●Intraocular lens implantation can be performed as part of the initial repair or as a secondary procedure if significant trauma has occurred. In patients with loss of the posterior capsule and zonular dehiscence a sutured intraocular lens may be indicated.

COMPLICATIONS

●Complications include uveitis, hemorrhage, elevated intraocular pressure (e.g. pupillary block, phacolytic glaucoma), and endophthalmitis.

●In order to avoid a fibrinous uveitis an intensive course of topical corticosteroids may be necessary.

COMMENTS

The pediatric patient

To prevent amblyopia and achieve rapid visual rehabilitation, primary intraocular lens implantation is preferred in the pediatric patient.