Abstract: Scleral lenses, as a special type of contact lenses, have undergone more than a century of development. Their materials and designs have been continuously improved. Modern scleral lenses cover the entire cornea and land on the sclera. Their unique three-zone design (optic zone, transition zone, and landing zone) creates a stable fluid reservoir in front of the cornea, effectively correcting high refractive errors and irregular astigmatism while providing physical protection to the cornea. Clinical studies have shown that the indications for scleral lenses mainly include keratoconus, moderate to severe dry eye, Stevens-Johnson syndrome, neurotrophic keratopathy, and other complex ocular surface diseases. They are also suitable for conditions such as incomplete eyelid closure, high refractive errors, and aphakia. However, potential risks such as corneal edema, neovascularization, and infection caused by fluid reservoir after lenses should not be overlooked, emphasizing the importance of standardized fitting, daily cleaning and care, and long-term follow-up. With the integration of high oxygen permeable materials and digital design technology, scleral lenses have become an important treatment option for complex ocular surface diseases and refractory ametropia.

Key words: Scleral lenses, Keratoconus, Ocular surface diseases