A rare case where laser peripheral iridotomy resulted in crystalline lens dislocation into the vitreous cavity. The patient was managed with pars plana vitrectomy, fragmatome lensectomy, anterior chamber intraocular lens and surgical iridotomy with a final best corrected visual acuity of 6/9. Multiple episodes of laser peripheral iridotomy carries a risk of complete lens dislocation.
Lens Dislocation Following YAG Laser Peripheral Iridotomy
From the Queen Elizabeth Hospital (SPM), Adelaide, Australia; the Royal Devon and Exeter Hospital (MS), Exeter, England; and the Musgrove Park Hospital (SR, RG), Taunton, England.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Sacha P. Moore, FRCOphth, NHS, 17/172 Wakefield Street, Adelaide, SA 5000, Australia.
Accepted: July 30, 2009
Posted Online: March 09, 2010
Acute angle closure glaucoma (AACG) secondary to pupil block is a known complication of ectopia lentis.1,2 YAG laser peripheral iridotomy (LPI) is the treatment of choice to reverse the pupil block and reduce the intra-ocular pressure. We present a case where LPI resulted in crystalline lens dislocation into the vitreous cavity.
A 76-year-old moderately hypermetropic woman presented with recurrent right unilateral AACG. This was despite apparently patent iridotomies following two attempts at LPI. Patent iridotomies were achieved in the left eye following the first session of LPI. A few hours following the third LPI session the patient returned complaining of poor vision. The lens was observed to be dislocated into the vitreous cavity. Further questioning revealed a history of recent multiple falls without direct ocular injury. Measurements at this time recorded: autorefraction spherical equivalent right +15 D, left +2.50 D, axial length right 21.99 mm, left 22.03 mm, anterior chamber depth right 2.71 mm, left 2.57 mm. There was no history or signs of any ocular or systemic abnormality associated with ectopia lentis (eg pseudoexfoliation, Marfan syndrome, homocystineuria, or uveitis). The fellow eye showed no phacodonesis and gonioscopy was normal. The patient was managed with pars plana vitrectomy, fragmatome lensectomy, anterior chamber intraocular lens and surgical iridotomy with a final best-corrected visual acuity of 6/9. Subsequent gonioscopy of the right eye showed no evidence of peripheral anterior synechiae.
This case demonstrated recurrent high intraocular pressure despite patent peripheral iridotomies and absentce of peripheral anterior synechiae. This is most likely to be due to an iridolenticular pupil block. A cataractous lens, which increases in anterior-posterior diameter and is anteriorly placed, could cause this. Ectopia lentis and aqueous misdirection are less common possibilities. It is uncertain whether the history of recent multiple falls is significant. We feel that there must have been pre-existing zonular deficiency for LPI to have precipitated lens dislocation. However, known risk factors for ectopia lentis were absent.
Unfortunately, no record was kept of the laser settings or technique used by any clinician at each session of LPI. This was usual practice for YAG laser in our department. In the author’s experience, this is also the case in many other departments. It is debatable whether the third laser iridotomy, in the presence of two apparently patent iridotomies, was necessary. It was felt by the attending clinician that these iridotomies must have been non-functioning and the intention was to try and create a further separate functioning iridotomy.
Other reports of lens dislocation are rare following LPI in eyes without pseudoexfoliation or ocular trauma. Melamed et al. reported a case associated with pseudoexfoliation and a history of trauma.3 Seo et al. described the treatment of two cases but gave no other details.4 Jorge et al. made useful recommendations to avoid lens rupture during LPI: careful case selection, avoiding enlargement through an already patent iridotomy and single-pulse, low energy, carefully focused shots.5 We would like to echo this advice to avoid zonular damage too.
LPI carries a risk of lens dislocation. Diagnosis and management of AACG should be carefully reassessed when there is poor response to LPI. Clinicians should always record accurate details of YAG laser settings and technique used.
- Ritch R, Shields MB. The secondary glaucomas. St Louis: Mosby, 1982;136–146.
- Madill SA, Bain KE, Patton N, Bennet H, Singh J. Emergency use of pilocarpine and pupil block glaucoma in ectopia lentis. Eye. 2005;19:105–107. doi:10.1038/sj.eye.6701417 [CrossRef]
- Melamed S, Barraquer E, Epstein DL. Neodymium: YAG laser-iridotomy as a possible contribution to lens disclocation. Ann Ophthalmol. 1986;18:281–282.
- Seo MS, Yoon KC, Lee CH. Phacofragmentation for the treatment of a completely posterior dislocation of the total crystalline lens. Korean J Ophthalmol. 2002;16:32–36.
- Jorge F-B. Iatrogenic lens rupture after a Neodymium: Yttrium Aluminium Garnet laser iridotomy attempt. Ann Ophthlamol. 1991; 23:346–348.