P 767Modification of retinal adhesion for macular translocation ultrastructural findings after artificial retinal detachment
P. Szurman, G. Thumann, U. Schraermeyer, K. U. Bartz-Schmidt
Purpose: To elucidate parameters reducing retinal adhesion and ultrastructural damage by artificial retinal detachment for macular translocation.
Method: Pigmented rabbits were vitrectomized and vitreous space was transfused for 10 min with different solutions. Calcium-free buffered solution was used in different osmolarity (300mOsm+500mOsm) and temperature (19°C + 34°C). To reduce retinal adhesion by ischemia IOP was raised to 60mmHg during transfusion with calcium-free buffered solution. Physiological buffered solution and no vitrectomy were used as control group. After transfusion retina was detached by transretinal injection of 1 ml physiological buffered solution in the subretinal space through a micropipette. Eyes were enucleated within 3 min, fixed with 2% glutaraldehyd and embedded for transmission electron microscopy and scanning electron microscopy.
Results: Only in the presence of calcium pigment epithelial fragments adhered to the retina. Ultrastructural examination revealed massive destruction with swollen and fragmented photoreceptor outer segments with partial 1055 of plasma membrane in control groups. Calcium-free buffered solution showed reduced adhesion significantly with retinal damage of less degree. However, EDTA-containing and hyperosmolar solutions revealed massive ultrastructural damage of all retinal layers despite the reduction of retinal adhesion. Raised temperature reduced the adhesive force moderately without additional damage, while ischemia did not influence retinal adhesion, but increased ultrastructural damage.
Conclusions: Artificial retinal detachment for macular translocation results in massive ultrastructural damage due to the adhesive strength. Biochemical and physical parameters significantly influence retinal adhesion and therefore the ultrastructural damage. However, retina shows strong susceptibility to physiological parameters and requires careful modification to avoid direct toxic effect. Modification of calcium and temperature seem to be a promising and preserving way.
Department of Ophthalmology, University of Cologne, D-50931 Köln