As every eye is not the same, the size of an ICL needs to be customized as per size of an individual eye. The ICL has to fit perfectly within the eye. If the size of the ICL is small it will be lose & it will float around in the eye. If the size is large, it will be too tight & apply pressure to adjoining areas. Slightest variation in size will affect the final outcome. The entire process of ICL screening is crucial & important. Anterior chamber depth (ACD) – anything more than 2.75 mm is acceptable, ideally it should be more than 3 mm. Spectacle power of the eye Angles of the eye Size of the cornea – white to white Curvature of the cornea – keratometry Thickness of the cornea – pachymetry Evaluation of the retina – this is important in every patient with high spectacle power or high myopia. In high myopes, the retina is usually weak & there can be breaks or holes in the retina. Examination of the retina is a simple procedure & is mandatory before surgery. Any breaks or holes in retina can be treated with lasers. These lasers are painless & quick. Taking care of these breaks is very important before undergoing ICL implantation.