Single residue AAV capsid mutation improves transduction of photoreceptors in the Abca4-/- mouse and bipolar cells in the rd1 mouse and human retina ex vivo.

Gene therapy using adeno-associated viral (AAV) vectors for the treatment of retinal degenerations has shown safety and efficacy in clinical trials. However, very high levels of vector expression may be necessary for the treatment of conditions such as Stargardt disease where a dual vector approach is potentially needed, or in optogenetic strategies for end-stage degeneration in order to achieve maximal light sensitivity. In this study, we assessed two vectors with single capsid mutations, rAAV2/2(Y444F) and rAAV2/8(Y733F) in their ability to transduce retina in the Abca4-/- and rd1 mouse models of retinal degeneration. We noted significantly increased photoreceptor transduction using rAAV2/8(Y733F) in the Abca4-/- mouse, in contrast to previous work where vectors tested in this model have shown low levels of photoreceptor transduction. Bipolar cell transduction was achieved following subretinal delivery of both vectors in the rd1 mouse, and via intravitreal delivery of rAAV2/2(Y444F). The successful use of rAAV2/8(Y733F) to target bipolar cells was further validated on human tissue using an ex vivo culture system of retinal explants. Capsid mutant AAV vectors transduce human retinal cells and may be particularly suited to treat retinal degenerations in which high levels of transgene expression are required.

Functional expression of Rab escort protein 1 following AAV2-mediated gene delivery in the retina of choroideremia mice and human cells ex vivo.

Choroideremia (CHM) is an X-linked retinal degeneration of photoreceptors, the retinal pigment epithelium (RPE) and choroid caused by loss of function mutations in the CHM/REP1 gene that encodes Rab escort protein 1. As a slowly progressing monogenic retinal degeneration with a clearly identifiable phenotype and a reliable diagnosis, CHM is an ideal candidate for gene therapy. We developed a serotype 2 adeno-associated viral vector AAV2/2-CBA-REP1, which expresses REP1 under control of CMV-enhanced chicken ß-actin promoter (CBA) augmented by a Woodchuck hepatitis virus post-transcriptional regulatory element. We show that the AAV2/2-CBA-REP1 vector provides strong and functional transgene expression in the D17 dog osteosarcoma cell line, CHM patient fibroblasts and CHM mouse RPE cells in vitro and in vivo. The ability to transduce human photoreceptors highly effectively with this expression cassette was confirmed in AAV2/2-CBA-GFP transduced human retinal explants ex vivo. Electroretinogram (ERG) analysis of AAV2/2-CBA-REP1 and AAV2/2-CBA-GFP-injected wild-type mouse eyes did not show toxic effects resulting from REP1 overexpression. Subretinal injections of AAV2/2-CBA-REP1 into CHM mouse retinas led to a significant increase in a- and b-wave of ERG responses in comparison to sham-injected eyes confirming that AAV2/2-CBA-REP1 is a promising vector suitable for choroideremia gene therapy in human clinical trials.

Calcification of hydrophilic acrylic intraocular lenses in combined phacovitrectomy surgery.

UNLABELLED: Two cases of postoperative intraocular lens (IOL) calcification in patients implanted with the Akreos Adapt IOL at the time of combined phacovitrectomy are described, along with clinical review of all patients implanted with this IOL type at our institution between November 2006 and September 2008. The IOLs explanted from the 2 cases were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The SEM of the explanted IOLs showed crystalline anterior surface and subsurface deposits; by EDX, the deposits showed high concentrations of calcium and phosphorous, consistent with calcium apatite. Twenty patients (20 eyes) attended for cohort review, and none showed IOL opacification. The reason calcification occurred in the 2 cases remains unknown, but clinicians should be aware of this potential complication. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Aciclovir-resistant herpes keratitis.

Herpes simplex virus (HSV) keratitis is a common cause of ocular morbidity. Resistance to aciclovir is probably under recognized. We describe three cases of aciclovir-resistant herpes simplex virus keratitis treated with systemic foscarnet and present a review of the pharmacological options available to manage this condition.

Plasmablastic lymphoma in the orbit: case report.

Plasmablastic lymphoma (PBL) is a rare entity most commonly identified in the oral cavity of immunodeficient patients. The immunophenotype of this condition shows a poor expression for B-cell markers but, in contrast, a strong reactivity for well-differentiated plasma cells markers, such as CD138, CD38, and epithelial membrane antigens. PBL survival is limited due to its highly aggressive local and metastatic behavior and poor response to treatment. Although it can involve different organs, there have been only a few cases involving the ocular adnexa. We describe a case of atypical rapidly progressive pre-septal brawny induration affecting the right orbit in a patient with HIV-related lymphoma.

Postoperative cilium entrapment by clear corneal incision.

A 75-year-old man had routine phacoemulsification cataract extraction with posterior chamber intraocular lens implantation in the left eye using a temporal corneal incision and inferior paracentesis. Examinations at 1 day and 1 week were unremarkable; however, at the 6-week assessment, a cilium was noted to have penetrated the external ostium of the paracentesis, with the proximal (follicle) end abutting the internal ostium of the wound. While the cilium was removed without incident, this chance finding may aid our understanding of how intraocular cilia are occasionally discovered following routine small-incision sutureless cataract surgery.

Traumatic expulsive iridodialysis after small-incision sutureless cataract surgery.

Phacoemulsification with intraocular lens (IOL) implantation was performed in the right eye of an 84-year-old woman using a small clear corneal incision. Ten weeks after surgery, the patient fell, which caused traumatic iridodialysis and hyphema with expulsion of the iris through the surgical corneal incision. Apart from a transient rise in intraocular pressure, no other complication was identified and the visual acuity returned to 20/20 within 2 months. The IOL remained in situ and undisturbed in the capsular bag, and the retina remained flat, suggesting that an IOL in the capsular bag may provide a stable barrier to prevent tissue loss from the posterior segment.

Effect of hinged lamellar keratotomy on post-keratoplasty astigmatism and vision.

PURPOSE: To show that hinged lamellar keratotomy alone affects refraction and vision in post-keratoplasty eyes. METHODS: A retrospective, non-comparative, interventional case series was conducted on 28 eyes of 26 patients who had two-stage laser in situ keratomileusis (LASIK) after penetrating keratoplasty. Records were reviewed with respect to the hinged lamellar keratotomy component of the procedure. The interval between keratoplasty and keratotomy was at least 1 year, and the follow-up period averaged 29 +/- 10 days. The Automated Corneal Shaper with nasal hinge was used. In addition to basic empirical astigmatism calculations, the Alpins method of astigmatism analysis was also employed to ensure that the influence of changes in cylinder axis were correctly taken into account when calculating the refractive change. RESULTS: Surgically induced astigmatism from hinged lamellar keratotomy was not statistically significant in this series; however, the range in values (-9.06 to +7.57 D) has potential clinical ramifications. Nearly 70% of cases studied experienced surgically induced astigmatism of at least 2 D. Mean preoperative uncorrected vision was logMAR 1.06 +/- 0.41, which improved marginally postoperatively to logMAR 1.03 +/- 0.44 (P = 0.36). Best spectacle-corrected visual acuity averaged logMAR 0.21 +/- 0.16 preoperatively, improving to logMAR 0.09 +/- 0.15 (range -0.18 to 0.42) postoperatively, which was a statistically significant improvement (P < 0.01). No difference in refractive or visual outcomes was identified when those with keratoconus were compared to those with other underlying corneal disease processes. CONCLUSION: Although mean surgically induced astigmatism was not statistically significant, hinged lamellar keratotomy caused considerable changes in astigmatism in nearly 70% of post-keratoplasty eyes studied. This suggests that clinically significant inaccuracies may result if a one-stage LASIK procedure is performed on such patients. The authors suggest that reassessment of refraction after keratotomy may improve refractive outcomes.