This unit of study provides candidates with the theoretical and practical foundations of the practise of cataract and refractive surgery. Successful students can demonstrate to the examiners that they have a detailed and comprehensive knowledge of corneal refractive surgery. On completion, successful students are able to: (1) Describe how an excimer laser and femtosecond laser work, (2) Describe how PRK, LASIK and SMILE laser are performed, (3) Demonstrate knowledge of the theory behind the lasers involved, (4) Describe indications and contraindications for the above procedures, (5) Understand the importance of corneal imaging in refractive surgery, (6) Demonstrate an understanding of the impact of systemic disease on refractive surgery patients, (7) Describe the management of corneal related refractive surgery complications, (8) Describe the causes and treatments of corneal ectasia, (9) Discuss lens based approaches to refractive surgery, (10) Have an understanding of the management of lens based related refractive surgery adverse events.