The ornamental design for an optical sightlens having a reticle, as shown and described.
FIG. 1 is a front view of an optical sight lens having a reticle showing my new design;
FIG. 2 is a rear view of the optical sight lens having a reticle; and,
FIG. 3 is a front perspective view of the optical sight lens having a reticle.
The side is a portion of the optical sight lens having a reticle that is not included in the claim. The dot dash dot broken line edges enclosing the side of the optical sight lens having a reticle depict portions of the article that are not claimed. The dot dash dot broken lines also depict the boundaries of the claim and form no part thereof.