Neuroradiology Case of the Month

March 2002

Jose A. Echeverri, MD, Akio Hiwatashi, MD, Reno L. Alessio, MD,
Ahmed Abdelhalim, MD, Toshio Moritani, MD, PhD,
P.L. Westesson, MD, PhD, DDS, and Henry Wang, MD, PhD

Clinical Presentation: A 45-year-old male was admitted after an accident with trauma to the left eye. A saw flung a two-by-four piece of wood in the left eye. The patient complained of pain and blurred vision.

Imaging Findings: There is dislocation of the left lens. The lens is located posteriorly in the left ocular globe, floating against the retina. In addition, there is swelling of the left preorbital soft tissues (Figs. 1 and 2).

Diagnosis: Traumatic Posterior Left Lens Dislocation.

Figure 1: Non-contrast enhanced CT: The right eye is normal. The left ocular globe is missing the lens.

Figure 2: Non-contrast enhanced CT: shows the dislocated left lens posteriorly against the retina.

Discussion: Dislocation of the lens can be diagnosed by both Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). With blunt trauma to the anterior globe the anterior-posterior diameter of the globe is suddenly compressed, which increases the coronal diameter causing rupture of the zonular fibers that hold the lens in place [1]. CT provides a useful adjunct in the assessment of ocular trauma, particularly when the clinical examination is limited [2].

Trauma is the most common cause of acquired lens subluxation-dislocation. Spontaneous atraumatic dislocation is commonly accociated with heredofamilial syndromes such as Marfan syndrome, homocystinuria, sulfite oxidase deficiency, hyperlysinemia, Elhers-Danlos syndrome, aniridia and congential glaucoma. Other causes include ocular processes such as staphylomas, ectasias, buphthalmias, high myopia, hypermature cataract, syphilis, etc.[3]. The lens can be dislocated anteriorly into the anterior chamber or posteriorly into the vitreous cavity, either of which can cause a type of glaucoma. After trauma, dislocated lenses are commonly found in the vitreous cavity, where they are generally free floating. Emergent surgical intervention is not indicated in these instances [4]. In fact, fitting a patient with a hard contact lens is acceptable treatment in an asymptomatic uncomplicated dislocation. However, most patients will have a pars plana victrectomy/lensectomy procedure with an intraocular lens implanted in the anterior or posterior chamber.

References:

1. Carmody RF. The Orbit and Visual Systems. In: Orrison, WW, Jr eds. Neuroimaging, 1st edition. Philadelphia, PA: W.B Saunders Company, 2000; 1009-1069.
2. Wang HE, Ger DS, Gould SW, In: Letters to the Editor: The Journal of Emergency Medicine, 2000; 19(1):73-75.
3. Streeten BW. Pathology of the Lens. In: Albert DM, Jakobiec FA, eds. Principles and Practice of Ophtalomology, ed 1. Philadelphia: W.B. Saunders; 1994: 2225-2232.
4. Onwuzuruigbo CJ, Fulda JG, Larned D, et al: Traumatic blindness after airbag deployment: bilateral lenticular dislocation. J of Trauma 1996; 40(2):314-316.