Sclera, the protective covering of the eye, is thinnest at the following site:
The sclera is the fibrous outer coating of the eye, consisting almost entirely of collagen. It is 1 mm thick posteriorly, 0.66 mm at the inseions of the rectus muscles, 0.33 mm beneath the rectus muscles and is thinnest just behind their inseions. Ref: Parsons' Diseases of the Eye By Ramanjit Sihota & Radhika Tandon, 21st edition, Page 218.
Apex
Limbus
In front of inseion of rectus muscle
Behind inseion of rectus muscle