Late dislocation of scleral-sutured posterior chamber intraocular lenses

PURPOSE: To examine a recent series of late scleral-sutured posterior chamber intraocular lens (PCIOL) dislocations to identify possible causes and preventive measures. SETTING: Price Vision Group, Indianapolis, Indiana, USA. METHODS: In this retrospective non-comparative interventional case series, 5 consecutive patients received treatment for dislocated scleral-sutured PCIOLs between July 2002 and March 2004. Dislocated lenses were resutured or replaced with another scleral-sutured PCIOL. RESULTS: Dislocation of scleral-sutured PCIOLs occurred 7 to 14 years after implantation. Four dislocations were spontaneous, and 1 was precipitated by trauma. In each case, the suture affixing 1 or both haptics failed. There was no evidence that the suture had eroded through the tissue or that the knot had untied. Microscopic analysis of an explanted IOL with remnants of the suture attached showed localized degradation and cracking of the polypropylene suture material where it had been embedded in the scleral tissue. CONCLUSION: Suture-fixated PCIOLs can dislocate due to degradation of the suture material over time. The use of larger diameter (9-0 instead of 10-0) polypropylene suture material and placement of the haptic and sutures in the ciliary sulcus to promote attachment of scar tissue may enhance the long-term stability of scleral-fixated PCIOLs.     

Acute haptic-induced ciliary sulcus irritation associated with single-piece AcrySof intraocular lenses

We report an analysis of 3 single-piece hydrophobic acrylic intraocular lenses (IOLs) that were explanted because of complications related to the presence of their haptics in the ciliary sulcus. In 2 cases, the IOL was primarily implanted in the ciliary sulcus because of inadequate posterior capsule support. In the third case, postoperative displacement of 1 haptic in the sulcus was associated with hyphema and vitreous hemorrhage. Ultrasound biomicroscopy confirmed the contact between the haptic and iris. Areas of iris atrophy were observed in all cases. Light microscopy and scanning electron microscopy of the explanted lenses revealed the presence of pigmentary dispersion on the anterior surfaces. In Case 3, the pigments were concentrated on the surface of the haptic that was displaced from the capsular bag and on the corresponding optic-haptic junction. Scanning electron microscopy also showed the IOL's squared edges and unpolished side walls. The flexibility and thickness of the single-piece hydrophobic acrylic haptics, as well as the square optic and haptic edges, may increase the risk for iris chafing when the haptics are in the sulcus. Therefore, sulcus fixation of this IOL design is not recommended.     

Functional analysis of the Ala67Thr polymorphism in agouti related protein associated with anorexia nervosa and leanness

AgRP is a neuropeptide that stimulates food intake through inhibition of central melanocortin receptors (MCRs). In humans, the non-conservative amino acid substitution Alanine (Ala) 67 Threonine (Thr) has been associated with Anorexia Nervosa and with leanness. In the present study, the cellular distribution, processing and in vitro and in vivo activities of Ala67 and Thr67 AgRP were investigated. Western blots of media and lysates of BHK cells stably transfected with Ala67 or Thr67 expression constructs showed identical AgRP bands. Both Ala67 and Thr67 AgRP colocalised with the Golgi apparatus, but not with the ER or lysosomes when expressed in Att20 D16V cells. Also, no differences were observed between the potencies of bacterially expressed Ala67 and Thr67 AgRP to stimulate MC4R in a reporter gene assay or inhibit food intake in rats. Taken together, no evidence was found for a functional defect of Thr67 AgRP related to MC4R interactions.