Macular translocation with chorioscleral outfolding: an experimental study

Macular translocation by chorioscleral infolding has been proposed as a surgical intervention for exudative age-related macular degeneration, but the surgery is unpredictable and can be associated with severe complications. We tested a new surgical technique, macular translocation with chorioscleral outfolding secured by neurosurgical clips.

This was a prospective interventional study in two parts; the first in human cadaver eyes and the second in pigs. Chorioscleral infolding was performed on six human donor eyes, and chorioscleral outfolding was performed on an additional six. The inner surface of the eye wall was measured, and then the fold was unfolded and the distance was measured again. In the second half of the study, macular translocation surgery was performed on 33 pig eyes with one of three sclera shortening methods: 1) a circumferential chorioscleral infolding using 5-0 nylon sutures, 2) a circumferential chorioscleral outfolding using scleral clips, or 3) a radial chorioscleral outfolding using scleral clips. Foveal translocation was measured.

The inner wall of the human cadaver eye was shortened in the chorioscleral infolding group by a mean of 1.6 mm, and in the chorioscleral outfolding group by 3.0 mm. In the pig eyes, the fovea was translocated a mean 2377 microm by circumferential suturing, 2582 microm by circumferential clipping, and 3386 microm by radial clipping. Irregular deformation of the globe was more apparent in the circumferential suture group. Undesirable retinal folds often formed after circumferential infolding but not after radial clipping.

Radial chorioscleral outfolding with clips is more predictable and effective than infolding. It produces more translocation and prevents folds across the fovea, one of the most undesirable complications in macular translocation surgery.