A light adjustable lens (LAL) is an optical device whose refractive properties can be changed after manufacture, such as by adjusting optical power by use of UV irradiation. However, light sources, such as lasers, for conducting UV irradiation may create high irradiances that can cause damage in instances where LALs are implanted into the human eye. Provided herein are systems and methods to modify a refractive property of a LAL by a lens adjustment system that provide improvements in the achieved optical power change and in other optical characteristics. A method for adjusting a LAL in an optical system comprises providing a LAL in an optical system, wherein the LAL comprises photo-polymerizable macromers in a first polymer matrix, providing an ultraviolet light source to generate an ultraviolet light, irradiating the generated ultraviolet light with a light delivery system onto the light adjustable lens with a center wavelength and with a spatial irradiance profile to photo-polymerize a portion of the photo-polymerizable macromers to change a dioptric power of the light adjustable lens by changing a refraction of the LAL over a refraction-change zone, thereby causing a wavefront sag, defined as half of a product of the change of the dioptric power of the optical system and the square of a radius of the refraction-change zone of the LAL, to be within 10% of its maximum over an ultraviolet spectrum, wherein the ultraviolet light source and the light delivery system are configured for irradiating the light adjustable lens with the ultraviolet light having a center wavelength in a range of 370 nm to 390 nm, an average irradiance in a range of 1 mW/cm2 to 50 mW/cm2 and a full width half maximum spectral bandwidth that does not exceed 10 nm. A lens adjustment system is also provided for adjusting a LAL.
