Effect of scleral shortening on axial length

Background: Partial thickness sclerectomy is the most commonly employed scl eral shortening techniqur: used in conjunction with pars plana vitrectomy i n the repair of myopia-associated macular holes in patients with staphyloma . Recently, scleral shortening induced through scleral invagination has bee n advocated as an adjunct in retinal translocation surgery. Objective: To determine whether a correlation exists between the amount of sclera infolding and the posttreatment reduction in axial length (AL) as a result of lamellar scleral resectioning or full-thickness scleral invaginat ion. Methods: Three groups of 10 eyes each underwent lamellar scleral resection with dissection of 6, 8, and 10 mm in height, and 1 group of 10 eyes underw ent a 10-mm invagination. Presurgical and postsurgical external AL of globe s with stabilized intraocular pressure was measured to +/-0.022-mm precisio n. Results: Average (+/-SD) AL shortening following lamellar resections for 6- , 8-, and 10-mm groups were 1.50+/-0.24, 2.10+/-0.13, and 2.65+/-0.24 mm, r espectively, acid 2.50 +/- 0.23 mm for the 10-mm invagination group. Differ ences in AL before and after scleral shortening were found to be significan tly different between dissections of different heights (P<.05), and not sig nificantly different between the 10-mm resection and invagination groups (P >.17). The AL of each group was shortened by approximately 25% of the resec tion-invagination height. The relation was quasilinear. Conclusions: Lamellar scleral resection and nonresected scleral invaginatio n reduce the ocular AL. The extent of the reduction significantly correlate s to the amount of removed or invaginated sclera. Clinical Relevance: Surgical shortening of the sclera is useful in the mana gement of several retinal disorders, but causes significant changes in AL.