A method of blocking an optical lens member , the method comprising: - An optical lens member providing step during which an optical lens member is provided, the optical lens member comprising first and second faces connected by an external periphery surface , the optical lens member further comprises a reference system identified by at least one sub-surface referencing element located between the first and second optical faces, wherein: o the first face comprises a first optical surface having a surface design associated with the reference system, o when an optical lens is manufactured from said optical lens member, said sub-surface referencing element remains at least partially on the optical lens as non-discernable; ∘ the referencing element is configured such that the position and/or orientation of the referencing element is measured by lighting the optical lens member through the external periphery surface, - a taping step (S2) during which an adhesive tape is provided on the first face of the lens member, - a blocker providing step (S3), during which a blocker with a blocker reference system is provided, - an optical lens member positioning step (S4) during which the first face of the optical lens member is placed on the blocker and positioned in a blocking position with respect to the blocker reference system using the sub-surface referencing element, and - a blocking step (S5) during which the optical lens member is blocked on the blocker in the blocking position. - An optical lens member providing step during which an optical lens member is provided, the optical lens member comprising first and second faces connected by an external periphery surface , the optical lens member further comprises a reference system identified by at least one sub-surface referencing element located between the first and second optical faces, wherein: o the first face comprises a first optical surface having a surface design associated with the reference system, o when an optical lens is manufactured from said optical lens member, said sub-surface referencing element remains at least partially on the optical lens as non-discernable; ∘ the referencing element is configured such that the position and/or orientation of the referencing element is measured by lighting the optical lens member through the external periphery surface, o the first face comprises a first optical surface having a surface design associated with the reference system, o when an optical lens is manufactured from said optical lens member, said sub-surface referencing element remains at least partially on the optical lens as non-discernable; ∘ the referencing element is configured such that the position and/or orientation of the referencing element is measured by lighting the optical lens member through the external periphery surface, - a taping step (S2) during which an adhesive tape is provided on the first face of the lens member, - a blocker providing step (S3), during which a blocker with a blocker reference system is provided, - an optical lens member positioning step (S4) during which the first face of the optical lens member is placed on the blocker and positioned in a blocking position with respect to the blocker reference system using the sub-surface referencing element, and - a blocking step (S5) during which the optical lens member is blocked on the blocker in the blocking position. <EOS>