During contact cyclophotocoagulation (CPC) energy is transmitted through the conjunctiva and the sclera by direct contact of a plain fibre tip. Alteration and scarring of the conjunctiva and the outer parts of the sclera cannot always be avoided. We used a new fibre tip which defocuses the laser light on the conjunctiva and sclera and focuses the laser light on the ciliar body. The coupling and focusing medium between fibre and sclera is a small glass ball (3 mm diameter).
Methods: Up to now we have treated 52 human eyes of 35 patients affected by refractory glaucoma using a diode laser (Zeiss Visulas II) coupled with a 200-microns fibre and a 3-mm focusing ball tip. In all cases 20-40 spots were applied 1.5 mm posterior of the limbus, power varied between 1.5 and 2.2 W and exposure time was 1.5 s.
Results: In all cases the conjunctiva and the sclera was unaltered. The mean follow-up time was 224 days. The mean IOP values +/- SD before treatment and 6 days, 4 weeks and 1 year after treatment were 40.9 +/- 7.1, 19.3 +/- 7.9, 22.4 +/- 14.8 and 17.2 +/- 11.3 mmHg. No positive, linear correlation was found between number of spots and IOP drop after 6 days. There was considerable individual variance. The main complications were anterior fibrinous uveitis (10%), slight vitreous haemorrhage (2/52) and transitory hypotony (2/52). In one enucleated eye structural alterations to the pigmented and non-pigmented epithelial cells of the ciliary body were found histologically.
Conclusions: Contact diode CPC can significantly reduce IOP, and the conjunctiva and sclera can be left totally unaltered by the focusing ball tip used in this study.