Corneal cross-linking guards against infectious keratitis: an experimental model.

BACKGROUND: PACK-CXL (photo-activated chromophore for keratitis-corneal cross-linking) is an alternative option in treatment of corneal infections. It inhibits corneal melting by increasing the stromal resistance, besides the microbicidal effect of photo-activated riboflavin. METHODS: Corneal infection with Pseudomonas aeruginosa and Staph aureus bacteria was induced in 20 eyes of 10 rabbits after 6 weeks of corneal cross-linking in half of the eyes, while the other acted as control group. Clinical and corneal histopathological examination was done to evaluate the extent of inflammation, ulceration, organism penetration, and depth of corneal stromal affection. RESULTS: The control eyes developed severe inflammation compared to the cross-linked eyes. Corneal melting occurred in 6 eyes in the control versus none in cross-linked group. Histopathological examination showed that the inflammation was confined to the superficial part of the stroma with localization of the inflammation in the cross-linked eyes in contrast to the control eyes that showed deep infiltration. CONCLUSION: PACK-CXL provides infection localization through increasing the corneal rigidity and resistance to enzymatic digestion, even in the absence of the riboflavin microbicidal role. So, early PACK-CXL is worth to be considered in the IK treatment algorithm.

Safety and Efficacy of Black Tea Extract in the Treatment of Acute Bacterial Conjunctivitis: A Rabbit Model.

PURPOSE: To determine the safety and efficacy of black tea extract in the treatment of bacterial conjunctivitis in a rabbit model and compare it with that of gatifloxacin drops. METHODS: Black tea extract was tested in vitro on bacterial cultures of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Forty-two rabbit eyes were cultured with either MRSA (n=21) or P. aeruginosa (n=21) and further divided into a control group (n=5), a tea group (n=8) treated with black tea extract, and a gatifloxacin group (n=8) treated with 0.3% gatifloxacin eye drops. Conjunctival swabs were collected on the third and fifth days. RESULTS: The tea extract successfully inhibited the growth of both organisms at a concentration of 400 mg/mL. Rabbits in the treatment groups showed a reduction in the clinical index on day 2 (P<0.01), unlike the control group (P=0.1), for both organisms. Resolution of conjunctivitis was achieved on days 4 and 5 in the tea and gatifloxacin groups, respectively. On days 3 and 5, while the control group still showed considerable bacterial growth, the tea and gatifloxacin groups showed its inhibition. CONCLUSION: Tea extract has antimicrobial effects similar to those of gatifloxacin in a rabbit model of conjunctivitis.

Femtosecond Laser-Assisted Penetrating Keratoplasty for Treating Infective Keratitis.

PURPOSE: To report the results of penetrating keratoplasty (PKP) assisted by femtosecond laser in the treatment of persistent infective keratitis. METHODS: Seven eyes of 7 patients with diagnosed infective keratitis were recruited. They showed no improvement on maximal medical therapy for a week. The causative organisms were Pseudomonas aeruginosa in 3 cases and Fusarium in 4 cases. All cases underwent femtosecond laser-assisted PKP with a mushroom-shaped cut. Postoperative antimicrobial medications were continued for 8-12 weeks. Sutures were removed after 6 months. Therapeutic success was defined as eradication of primary infection. Functional success was considered when visual function improves to 20/200 or better. RESULTS: All 7 eyes underwent femtosecond laser-assisted PKP. There were no intraoperative complications, and all patients had uneventful recipient cornea separation. Anatomic, therapeutic, and functional success was achieved in all patients. During the 6-month follow-up period, no recurrence of infection was reported. The average preoperative corrected distance visual acuity (CDVA) was 2.07 log of the minimal angle of resolution (LogMAR) ± 0.21, whereas at 6 months postoperatively, the average CDVA was 0.17 LogMAR ± 0.13, with a P value of 0.00025. CONCLUSIONS: Femtosecond laser-assisted PKP was found to be an effective method for treating infective keratitis (particularly that caused by Pseudomonas aeruginosa and Fusarium) that did not respond to medical treatment. Early surgical intervention before the disease becomes advanced is recommended.

Results of Femtosecond Laser-Assisted Descemet Stripping Automated Endothelial Keratoplasty.

PURPOSE: To evaluate femtosecond laser in DSAEK surgery as an improvement to manual DSAEK. SETTINGS: Department of Ophthalmology, Cairo University. DESIGN: A retrospective observational clinical study. METHODS: 20 eyes with SBK and Fuchs' dystrophy underwent a Femto-assisted DSAEK by laser cutting of two matching posterior stromal discs in the recipient and donor corneas and then fitting the donor disc in the posterior corneal defect of the recipient using Busin's glide or Terry forceps. RESULTS: Corneal thickness decreased significantly from a mean of 900-micron preoperative values (900.7 m) to 562 m postoperatively. Evidence of side healing was documented by OCT. One patient had a double AC, one patient had an air interface entrapment "Double Bubble," one patient had a fungal infection and was treated by a therapeutic penetrating keratoplasty, and one patient had a CMO. CONCLUSION: Femtolaser-assisted DSAEK may be superior to manual techniques as it offers better centration, thinner graft/host complex, earlier corneal detergecense, and stronger healing. This study was registered at Researchregistry.com with a UID: researchregistry2274.