Purpose. Birds and lizards have a third eyelid called “nictitans”. In mammalians semi-lunar fold represents the third eyelid atrophic remnant. In human anatomy, semi lunar fold has a fibrous skeleton connected with the posterior recessus of Tenon's capsule through the orbital fascia. The aim of this study is the evaluation of a deep posterior subtenon injection technique according to this special anatomy and derived from Ripart's method.

Material et Method. Technique: The needle was placed under the semi-lunar fold tangentially to the globe. Then the eye was turn in adduction and the needle was verticalized and moved inward. Then the needle perforated orbital fascia and Tenon&'s capsule before injection in Tenon's capsule posterior recessus. Two evaluations was done:

Résultats.

• Analgesia was excellent without akinesia in the two techniques. There were less chemosis and conjunctival hemorrhages in deep posterior subtenon injections than with the Greenbaum cannula.
• In 11 eyes: visual acuity was increased and biomicroscopy was qualitatively improved after triamcinolone injections. 1 eye worsened a previous cataract. No glaucoma nor subconjunctival deposits and orbital fat atrophy was observed.

Conclusions. Anatomical characteristics of the semi-lunar fold allow safe and useful deep posterior sub-tenon injections.