Implantable Collamer Lens Dislocation

Implantable Collamer Lens Dislocation Dear Editor: Although the implantation of implantable collamer lens (ICL), a posterior chamber phakic intraocular lens (PCPIOL), has been proven to be an effective, predictable and reversible surgical technique to correct high myopia and hyperopia, it does carry a potential risk of postoperative complications, such as cataract formation and pupillary block.1 We describe a previously unreported complication related to sudden occiput injury after ICL implantation. A 31-year-old man had bilateral nonsimutaneous implantation of ICLs. There were no intraoperative complications. Uncorrected visual acuity (UCVA) in each eye was 0 logarithm of the minimum angle of resolution (logMAR) at the 1 day postoperative examination, and the ICL vault was adequate in each eye. Four months postoperatively, the patient returned on an emergency basis complaining of sudden, painless blurred vision in the right eye. UCVA was 0.1 (logMAR) in the right eye and could not be corrected by spectacle lens. Contrast sensitivity in the right eye was significantly reduced compared with the left eye. The slitlamp examination of the anterior segment showed monolateral ICL subluxation in right eye. The subluxation was situated on the nasal-inferior footplate that had moved forward into the anterior chamber and entrapped by the pupil (Figure1, available at http://aaojournal.org). No secondary cataract and other complications were observed. Reposition of the ICL was performed under pupillary dilation. UCVA of the repositioned eye was 0 (logMAR) at the 1 day postoperative examination and ⫺0.1 (logMAR) 3 months later. Contrast sensitivity in the right eye recovered to the primary postoperative level (Table 1, available at http:// aaojournal.org). According to our knowledge, this report is the first reported case of ICL subluxation as a consequence of sudden occiput injury. The situation is rare. The patient was working in a dark room. His head heavily dashed upon an iron scaffold when he stood up from squatting position. We hypothesize that the tremendous shock wave from backside was the key factor that pushed the phakic ICL forward. Another key factor leading to subluxation was the enlargement of the pupil under the dark situation, thus enabling the haptic of the ICL to have possibility to dislocate into the anterior chamber and be entrapped by the pupil. ICL is the only marketed PCPIOL approved by the United States Food and Drug Adminstration.2 ICL has undergone 4 generations of modification and is considered to be a stable and promising implant. The current implantable collamer lens is a flat plate-haptic, single-piece design with a rectangular shape. The design allows the lens to maintain a stable centered fixation in the posterior chamber.3

Other types of PCPIOL are debated due to higher incidence of cataractogenesis and phakic IOL decentration. Decentration was an important issue in Fyodorov’s posterior chamber phakic IOL because it was manufactured in only 1 size.4 Due to the high incidence of postoperative complications, these PCPIOLs are no longer manufactured. The silicone posterior chamber phakic refractive lens (PRL, CIBA Vision, Atlanta, GA) is supposed to “float ” in the aqueous between the lens and iris. Spontaneous dislocation of PRL into the vitreous cavity was reported by different authors in at least 7 cases.5 The constant friction between the silicon haptics and the zonular fibers might be the cause of focal damage of zonular fibers. Up to now, there has been no report of spontaneous dislocation bothering implantable collamer lens. The differences in complications might contribute to the design and the hydrophilic material of ICL. The haptics of ICL are designed to located in the sulcus, instead of zonular fibers. Even in the cases that rotations were observed, which indicated that the diameters of the ICLs were small, the extreme tips of the haptics were correctly located in the sulcus. The hydrophilic material of ICL is soft, flexible, and biocompatible, less traumatic than silicone. This case suggests that particular caution must be taken in an eye with a phakic implant, especially in dark conditions. In our report, although the ICL subluxation happened under special circumstance, there was no secondary cataract detected after injury and in the follow-up examination at the third month. Long-term studies are warrented to investigate the stability and the possible cataract formation rates with the phakic intraocular lens in the setting of blunt trauma. JUN KONG, MD, PHD XING JUN QIN, MD, PHD XIAO YAN LI, MD, PHD JIN SONG ZHANG, MD BO QU, MD, PHD Shenyang, China References 1. ICL in Treatment of Myopia (ITM) Study Group. United States Food and Drug Administration clinical tiral of the implantable collamer lens (ICL) for moderate to high myopia. Three-year follow-up. Ophthalmology 2004;111:1683–92. 2. Chang JS, Meau AY. Visian Collamer phakic intraocular lens in high myopic Asian eyes. J Refract Surg 2007;23:17–25. 3. Petternel V, Köppl CM, Dejaco-Ruhswurm I, et al. Effect of accommodation and pupil size on the movement of a posterior chamber lens in the phakic eye. Ophthalmology 2004;111: 325–31. 4. Utine CA, Bayraktar S, Kaya V, et al. ZB5M anterior chamber and Fyodorov’s posterior chamber phakic intraocular lenses: long-term follow-up. J Refract Surg 2006;22:906 –10. 5. Eleftheriadis H, Amoros S, Bilbao R, Teijeiro MA. Spontaneous dislocation of a phakic refractive lens into the vitreous cavity. J Cataract Refract Surg 2004;30:2013– 6.

399

Ophthalmology Volume 117, Number 2, February 2010

Figure 1. The subluxation was situated on the nasal-inferior footplate that had moved forward into the anterior chamber and entrapped by the pupil.

Table 1. Preoperative and Postooperative Contrast Sensitivity Subluxation RE/LE

After Reposition RE/LE

Contrast sensitivity without glare, Photopic 85.cd/M2 Log CS (1.5 c/d) 1.93/2.0 2.0/2.0 Log CS (3 c/d) 1.90/1.94 2.06/2.0 Log CS (6 c/d) 1.51/1.69 1.85/1.81 Log CS (12 c/d) 0.90/0.90 0.90/0.90

Preoperative RE/LE

Postoperative RE/LE

1.39/2.0 1.60/1.97 1.65/1.79 0/0.90

2.0/2.0 2.06/2.05 1.85/1.81 0.90/1.0

Contrast sensitivity without glare, Mesopic 3.cd/M2 Log CS (1.5 c/d) 1.69/1.75 1.85/1.81 Log CS (3 c/d) 1.60/1.73 1.87/1.81 Log CS (6 c/d) 1.51/1.56 1.69/1.65 Log CS (12 c/d) 0/0 0.90/0.90

1.26/1.81 1.46/1.81 0/1.65 0/0

1.89/1.85 1.85/1.90 1.56/1.60 0.90/0.90

Contrast sensitivity with glare, Photopic 85.cd/M2 Log CS (1.5 c/d) 1.38/1.69 1.89/2.0 Log CS (3 c/d) 1.69/1.75 2.10/2.20 Log CS (6 c/d) 1.51/1.46 1.65/1.70 Log CS (12 c/d) 0.90/0.90 1.08/1.18

1.25/2.0 1.30/2.0 1.08/1.70 0/0.9

1.90/2.0 2.06/2.20 1.69/1.73 1.08/1.18

Contrast sensitivity with glare, Mesopic 3.cd/M2 Log CS (1.5 c/d) 1.56/1.75 1.83/1.85 Log CS (3 c/d) 1.26/1.46 1.51/1.67 Log CS (6 c/d) 0/0 0.9/1.08 Log CS (12 c/d) 0/0 0/0

1.08/1.81 0/1.65 0/1.08 0/0

1.75/1.81 1.46/1.65 0.9/1.08 0/0

c/d ⫽ cycle per degree; CS ⫽ contrast sensitivity; LE ⫽ left eye; RE ⫽ right eye.

399.e1