Eyelashes typically grow on the edge of the eyelid, which is a natural physiological structure. Technically, it is not possible to grow eyelashes directly on the surface of a single eyelid away from the normal lash line. Here are the specific reasons:
- Anatomical and Physiological Limitations: Eyelashes grow from hair follicles located in the dermis of the eyelid margin. The distribution and development of these hair follicles are determined during embryonic development and are part of the specific anatomical structure of the eyelid. The skin on the surface of the single eyelid does not have the necessary hair follicles for eyelash growth, and the cellular composition and physiological environment of this area are not conducive to the growth and development of eyelashes.
- Lack of Necessary Growth Factors and Signals: The growth of eyelashes is regulated by a variety of growth factors, hormones and signaling pathways. These regulatory factors act specifically on the hair follicles at the eyelid margin to promote the growth and cycling of eyelashes. The skin on the single eyelid does not receive these specific growth signals and lacks the internal and external conditions required for eyelash growth.
However, in some cases, such as after eyelid surgery or due to certain skin diseases, the appearance of the eyelid may change, but this does not mean that eyelashes can grow on the single eyelid. If there are abnormal hair growth phenomena on the eyelid, it is usually considered a pathological condition, such as trichiasis (abnormal growth direction of eyelashes) or the growth of other abnormal hairs, which requires medical attention and treatment.
