"Scler-" is a medical prefix derived from the Greek word "skleros," meaning "hard." It is used in various medical terms to indicate hardness or a condition related to the sclera, the white outer layer of the eye. 

Examples of medical terms containing "scler-": 

• Scleroderma: A skin condition characterized by hardening and thickening of the skin.
• Sclerokeratitis: Inflammation of the sclera and cornea.
• Sclerosing multiple sclerosis (MS): A form of MS where the myelin sheath covering nerves becomes hardened.
• Scleromalacia: Softening of the sclera.
• Sclerectomy: Surgical removal of part of the sclera.