Toll-like receptors in corneal ectasia: linking innate immunity to keratoconus.

Clinical manifestations of keratoconus (KC) are well described; however, its exact pathophysiology remains unknown. While KC is typically known as a primarily degenerative disease which progression is accelerated by mechanical trauma, Toll-like receptors (TLRs) have emerged as key contributors to disease development. TLRs are protein receptors that play a crucial role in the body's innate immune response. This systematic review was carried out using Web of Science, Scopus, MEDLINE, and EMBASE databases up to May 2025 to investigate TLRs expression in KC and corneal ectasia. These studies suggest a potential role of TLR2 and TLR4 in the early diagnosis and therapeutic management of corneal ectasia. Nevertheless, further studies are required to clarify the precise dynamics and clinical effects of TLRs in corneal ectasia.