Monofilament line at 5.20mm spacing provides reference to the size of the optic disc. Estimate the size of inflammatory/non inflammatory retinal lesions. Grid spacing aides in estimating the size of ocular tumors. Easily estimate the amount of disk edema. Easily fits onto anterior side of Ocular 20D Indirect lenses*. The Ocular 20D Indirect Lenses are sold separately (see related products). *Lens design with diamond knurl pattern only
