Alteration of the vascular supply in the rabbit ciliary body by transscleral diode laser cyclophotocoagulation
T. Schlote1, J. Beck1, J. M. Rohrbach1, R. H. W. Funk2
Background: Beside the direct destruction of the non-pigmented ciliary epithelium by cyclodestructive procedures, further mechanisms are responsible for the decrease of intraoculare pressure. This study evaluates the alteration of the ciliary body vascularization by transscleral diode laser cyclophotocoagulation in rabbit eyes.
Methods: Pigmented chinchilla bastard rabbits were used. Preliminary experiments were conducted to detemine the parameters for diode laser cyclophotocoagulation of the pars plana or pars plicata. Then, treatment of the pars plicata (3 rabbits) or pars plana (3 rabbits) was performed in the right eye of 6 rabbits. After 2, 6 and 12 weeks histologic and electronmicroscopic studies were performed. Furthermore, 3 rabbits received pars plicata cyclophhotocoagulation of the right and pars plana cyclophotocoagulation of the left eye. After 2, 6 and 12 weeks, vascular casts of the ciliary body were investigated by scanning electron microscopy.
Results: The morphologic studies showed a marked coagulation necrosis with subsequent atrophy and fibrosis, but without regenerative elements after diode laser cyclophotocoagulation. Examination of vascular casts of the ciliary body revealed a marked rarefication of vessels within the treated areas of the ciliary body in all eyes. No definitive regerative processes were observed.
Conclusions: This study demonstrates a marked, probaby irreversible rarefication of the ciliary body vascularization after diode laser cyclophotocoagulation, which probably acts as a strong synergistic mechanism in the decrease of intraocular pressure.
1University Eye Hospital, Schleichstr. 12, D-72076 Tübingen, Germany