Microbiological profiles of fungal keratitis: a 10-year study at a tertiary referral center.

BACKGROUND: Given the rise in cases of fungal keratitis in recent years, this study was performed to better elucidate the microbiological profile, risk factors, and surgical intervention rates of fungal keratitis at a tertiary referral center in the Southeastern USA. FINDINGS: This is a retrospective case series of fungal keratitis infections treated at Duke University Eye Center from January 1, 1998, to October 6, 2008. Of the 4651 culture-proven corneal ulcers identified, 63 (1.4 %) were positive for fungal keratitis with a total of 69 fungal organisms isolated. The majority of isolates were filamentous species (44 of 69, 64 %), and the most commonly isolated organism was Curvularia (11 of 69, 16 %). Bacterial coinfections were found in 24 of the 63 cases (38 %). The most commonly associated risk factors were contact lens wear (n = 15, 24 %) and prior penetrating keratoplasty (PKP) (n = 15, 24 %). Twenty-three cases (37 %) required surgical intervention. The rate of surgical intervention was highest in patients with prior PKP (7/15, 47 %). CONCLUSIONS: In this study, the leading risk factors for fungal keratitis were contact lens wear and prior PKP. Filamentous species were the most common causative pathogens. A relatively high rate of mixed bacterial-fungal infections was found. Patients with prior PKP were more likely to require surgery than patients without history of keratoplasties.

Clinical outcomes of xeno-free allogeneic cultivated limbal epithelial transplantation for bilateral limbal stem cell deficiency.

PURPOSE: To report the clinical outcomes of allogeneic cell-based therapy for bilateral corneal blindness due to limbal stem cell deficiency (LSCD). METHODS: This retrospective study included 28 eyes of 21 patients, at least 8 years of age, with bilateral and total LSCD, treated between 2001 and 2010. A limbal biopsy was obtained from the eye of an adult living related donor. The limbal epithelial cells were cultivated in the laboratory using a xeno-free explant culture technique and transplanted onto the recipient eye after 10-14 days. All transplant recipients received topical and systemic immunosuppressants. RESULTS: At a mean follow-up of 4.8 ± 2.8 years, 20 (71.4%) eyes maintained a completely epithelised, avascular and stable corneal surface, and among them 13 (46.4%) eyes subsequently underwent a penetrating keratoplasty (PK). The Kaplan-Meier survival rate of the PK allograft was 76.9 ± 11.7% at 1 year with a median survival of 3.3 years. Visual acuity improved to 20/60 or better in 19 (67.8%) eyes. No donor or recipient eyes developed serious ocular complications. CONCLUSIONS: Allogeneic cultivated limbal epithelial transplantation, followed by PK when needed, can successfully restore the ocular surface and improve vision in patients with corneal blindness due to bilateral LSCD.

Dislocation of the donor graft to the posterior segment in descemet stripping automated endothelial keratoplasty.

PURPOSE: To report a series of dislocations of the donor graft into the posterior segment associated with Descemet stripping endothelial keratoplasty (DSAEK) and to identify possible risk factors for dislocation and clinical outcomes. DESIGN: Retrospective case series. METHODS: Cases of donor graft dislocation into the posterior segment associated with endothelial keratoplasty were identified from the clinical experience of 7 surgeons. Observations included the preoperative surgical history of each eye, preoperative and postoperative visual acuity, management of the complication, and the postoperative clinical course. No identified cases were excluded from this series. RESULTS: Eight posterior graft dislocations were associated with DSAEK surgery. Each eye had a history of vitrectomy. Five eyes had sutured posterior chamber intraocular lenses, 1 eye had a sulcus intraocular lens, and 2 eyes were aphakic. Each eye required repeat grafting, and in 6 of 8 eyes, pars plana vitrectomy was used to remove the dislocated graft. Final visual acuities ranged from 20/30 to no light perception. CONCLUSIONS: Graft dislocation into the posterior segment is a rare complication of DSAEK surgery that can lead to permanent vision loss. It has occurred in eyes that have undergone previous vitrectomy and complicated intraocular lens placement or were aphakic. As is the case with a dropped lens nucleus during cataract extraction, visual acuities after a dropped DSAEK graft range from very good to no light perception. Better postoperative results seem to be associated with prompt removal of the posteriorly dislocated graft.

Cataracts: we have perfected the surgery, but is it time for prevention?

PURPOSE OF REVIEW: This review presents a discussion of cataract prevention, with a focus on the societal burden of untreated cataracts and pathophysiologic mechanisms of prevention. RECENT FINDINGS: Multiple studies have implicated cataract surgery and vision loss due to cataract as a major cause of disability and lost productivity. Long-term use of antioxidants such as vitamin C, lutein, and zeaxanthin have been associated with lower incidence and progression of cataracts, but prospective studies of vitamin supplementation have shown little effect. There are currently over 400 cataract-related clinical trials; one trial of a topical medication for the treatment of cataract is currently in progress. SUMMARY: Vision loss due to cataract, disability associated with cataract blindness, and the surgical treatment of this disease present a significant public health burden. Useful strategies for prevention may include public health campaigns targeted at young adults, with a focus on making healthy choices to prevent this disease.

Endothelial Keratoplasty: From DLEK to DMEK.

The last decade has heralded a revolutionary shift in the treatment of corneal endothelial disease. Only 15 years ago, the only surgical treatment for pseudophakic bullous keratopathy and Fuchs dystrophy was penetrating keratoplasty (PK). Although used successfully for over a century, PK requires many months of refractive adjustments before the eye achieves visual stability. Starting with the advent of posterior lamellar keratoplasty in the late 1990s, a number of procedures have been developed, refined, and widely adopted, which have given patients faster recoveries and improved globe stability in comparison to traditional corneal transplantation. Each iteration of endothelial keratoplasty (EK) has involved the increasingly selective transplantation of corneal endothelial cells. Preliminary results of the most recent form of EK, Descemet's membrane EK, suggest that pure endothelial cell transplantation is on the horizon.

Descemet stripping automated endothelial keratoplasty in a child.

We present the case of a 9-year-old patient with corneal decompensation that was treated with Descemet stripping automated endothelial keratoplasty (DSAEK) and followed for 18 months. Although the procedure has been used successfully in adult populations, to our knowledge, this is the first report of DSAEK with long-term follow-up in a child. The outcome suggests that endothelial keratoplasty may be a good alternative to penetrating keratoplasty in children. Endothelial keratoplasty is a new form of corneal transplantation that promises faster visual recovery compared with penetrating keratoplasty. With endothelial keratoplasty, the corneal architecture is preserved; therefore, large spherical and astigmatic errors are not induced, and stable refraction is achieved earlier in the course of therapy.

Nutrition and the prevention of cataracts.

PURPOSE OF REVIEW: Oxidative stress is a major cause of cataract development. Numerous studies have been published regarding the effects of nutritional supplementation on cataract progression. RECENT FINDINGS: Basic science research has demonstrated a protective effect of antioxidants on lens tissue, and supplementation with vitamin C and lutein/zeaxanthin has been associated with a decreased risk of cataract formation in multiple observational studies. One large interventional trial demonstrated a significant difference in participants treated with high-dose vitamin C versus placebo, but a more recent interventional study did not replicate these findings. In a review of the carotenoids lutein and zeaxanthin, the Food and Drug Administration concluded there is insufficient evidence to suggest that supplementation with these carotenoids lowers the risk of cataract formation. While high doses of multivitamins, antioxidants, or lutein and zeaxanthin are unlikely to be of significant ophthalmic benefit to the general public, these nutrients may help individuals exposed to high oxidative stress, such as heavy smokers, and those with poor nutrition. SUMMARY: Supplementation with vitamin C, lutein, zeaxanthin, or a multivitamin may help certain populations, but is unlikely to affect the progression of cataracts in most patients.

Evaluation of a new CPC-to-gauge bonding technique with the use of in vitro fluid flow.

Strain gauging enables the measurement of bone deformation during physical activity, leading to a better understanding of the physiological effects of loading on bone growth and remodeling. Development of a technology that will withstand long-term in vivo exposure and bond securely to bone is imperative for accurate, consistent measurement collection. Polysulfone is currently used to attach calcium-phosphate ceramic (CPC) particles, which promote bone-to-gauge bonding, to polyimide-backed strain gauges. This study evaluated the use of an implant-grade epoxy as an alternative CPC-polyimide adhesive. Polyimide-epoxy-CPC interfaces were loaded to failure and shear strengths calculated. In vitro studies providing a constant flow of medium over test specimens were designed, and long-term in vitro fluid exposure studies of the epoxy's shear strength were conducted. Average shear strength of polysulfone-polyimide interfaces were reported to be 7 MPa. The average shear strength of the epoxy-polyimide interface before long-term in vitro exposure was 17 MPa, which is stronger than the shear strength of the bone-CPC interface. The strength of the epoxy-polyimide interface decreased to 6.8 MPa after 24 weeks in vitro and 3 MPa after 24 weeks in vivo.