[Low grade endophthalmitis caused by P. acnes : Case report]. / Low-grade-Endophthalmitis verursacht durch P. acnes : Eine Kasuistik.

Low grade endophthalmitis is usually a chronic indolent inflammation that may be misdiagnosed as noninfectious uveitis. Therefore, this form of endophthalmitis is often unsuccessfully treated with corticosteroids. We describe the case of a patient with low grade endophthalmitis caused by Propionibacterium acnes after cataract surgery. This case report presents the difficulties in establishing the diagnosis of this form of endophthalmitis as well as the benefits of a combined operative therapy with pars plana vitrectomy, intravitreal antibiotics and posterior capsulectomy for successful treatment in such cases.

[Enzymatic evidence of the depth dependence of stiffening on riboflavin/UVA treated corneas]. / Enzymatischer Nachweis der Tiefenabhängigkeit der Vernetzungswirkung von Riboflavin/UVA an der Hornhaut.

PURPOSE: It has been shown that the treatment of keratoconus with riboflavin/ultraviolet A (UVA) causes significant stiffening of the cornea due to cross-linking. The aim of this study was to evaluate how deep the mechanical stabilization after collagen cross-linking could be shown biochemically. METHOD: Ten out of 20 enucleated porcine eyes were treated with riboflavin as a photosensitizer and UVA (370 nm, 3 mW/cm2, 30 min). The other 10 eyes served as controls. With a Microkeratom device, two flaps with a thickness of 200 microm and a diameter of 8 mm were cut off from each eye and put in a collagenase solution (NaCl plus collagenase A, 1:1). The surfaces of the flaps were measured digitally every day to characterize the dissolving behavior. RESULTS: The resistance (regarding corneal collagen against enzymatic digestion) of the treated superficial flaps was considerably higher (p=0.001) compared to those that were cut secondarily and to the control flaps. But even the flaps from deeper layers showed a significant increase in resistance (p=0.02) compared with the untreated flaps. The half-life of the surfaces of the treated superficial flaps was 220 h; of those cut secondarily, it was 80 h. Both untreated flaps had a half-life of 50 h. CONCLUSIONS: The biochemical study showed that the treatment of the cornea with riboflavin/UVA leads to significant collagen cross-linking not only in the anterior slice of 200 microm but also in the following 200 microm. This locally limited cross-linking effect may be explained by the absorption behavior for UVA of the riboflavin-treated cornea; 65% of UVA irradiation is absorbed in the first 200 microm and only 25-30% in the next 200 microm. Therefore, deeper-lying structures and especially the endothelium are not affected.

[A new treatment of keratectasia after LASIK by using collagen with riboflavin/UVA light cross-linking]. / Eine neue Behandlung der Keratektasie nach LASIK durch Kollagenvernetzung mit Riboflavin/UVA-Licht.

BACKGROUND: Keratectasia is one of the most severe complications after refractive laser surgery. Usually penetrating keratoplasty is the treatment of choice to achieve an optical rehabilitation in such cases. PATIENTS AND METHODS: We report on a female patient who developed keratectasia in both eyes 4 weeks after LASIK. Due to a severe keratectasia 10 months after LASIK, a treatment with riboflavin/UVA cross-linking was performed. RESULTS: Due to the induced collagen cross-linking the biomechanical status of the cornea was stabilized and a progression of the keratectasia was prevented. The postoperative refraction and corneal topography have been stable for 18 months. CONCLUSION: Collagen cross-linking leads to a stiffening of the anterior parts of the corneal stroma. The increase of biomechanical stability can stop the progression of a keratectasia after LASIK by means of a simple procedure.