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 during which an adhesive tape is provided on the first face of the lens member, - a blocker providing step, during which a blocker with a blocker reference system is provided, - an optical lens member positioning step 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 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 during which an adhesive tape is provided on the first face of the lens member, - a blocker providing step, during which a blocker with a blocker reference system is provided, - an optical lens member positioning step 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 during which the optical lens member is blocked on the blocker in the blocking position.