[Basic principles and clinical application of retinal laser therapy]. / Grundlagen und klinische Anwendung der Lasertherapie an der Netzhaut.

The scientific background of laser photocoagulation of the ocular fundus was studied extensively by several investigators in the 1970 s and 1980 s. The basic principles were successfully resolved during that time and clinical consequences for proper application of the laser photocoagulation for various diseases were deduced. The present paper gives an overview about the physical basics of laser-tissue interactions during and after retinal laser treatment and the particular laser strategies in the treatment of different retinal diseases. Thus, it addresses the issue of the impact on tissue of laser parameters as wavelength, spot size, pulse duration and laser power. Additionally, the different biological tissue reactions after laser treatment are presented, such as, e. g., for retinopexia or macular treatments as well as for diabetic retinopathies. Specific laser strategies such as the selective laser treatment of the RPE (SRT) or the transpupillary thermotherapy (TTT) are presented and discussed.

[Surgical worm extraction in loa loa ophthalmia]. / Chirurgische Wurmentfernung bei Loa-Loa-Ophthalmie.

BACKGROUND: Loa Loa is a chronic parasitemic disease which is endemic in the tropical rain forests of Western Africa. Vector of this disease is a mangrove fly with the name Chrysops. Besides the eye worm and skin affections a systemic infection with microfilariae is common. PATIENT: A West African tourist from Bangibe showed up at the university eye clinic. His complaints were a red eye and a mobile subconjunctival tumor (Fig. 1) that showed vermiform movements. The worm was transparent and 4-5 cm in length. After topical anaesthesia and the attempt to paralyze the worm (1) with Pilocarpine 2% it vanished. Two days later the patient showed up in the morning for the planned blood test. No worm was visible at that time but at noontime the blood test was carried out and at that time the worm was visible in the nasal conjunctiva. This time the worm was removed without delay under topical anaesthesia. The worm was fixed with a forceps through the conjunctiva which was opened for 0.5 cm. The worm was grasped with a second forceps and drawn out under massive vermiform movement. Systemic therapy was recommended with Hetrazan (Diethylcarbamazine) using Corticosteroides and Antihistamine to minimize allergic side effects by the therapy due to the systemic microfilariae blood load. Eosinophilia was 8%. CONCLUSIONS: A subconjuctival Loa Loa worm can be removed under topical anaesthesia by fixing it with a forceps through the conjunctiva and opening it and grasping the worm with a second forceps. According to our experience the paralyzation with Pilocarpine cannot be realized. Careful systemic therapy avoiding reported allergic side effects with Hetrazan which is not available in Germany is necessary.