Purpose The purpose of this thesis was to create a clinical assessment guideline for optometrists for managing pre-surgery cataract patients in Finland and to create an easily understandable theoretic background about the basics of the human lens crystalline and the cataract.

Methods This thesis is a literature review analysis-based innovation project to produce a guideline for Finnish optometrists for pre-cataract surgery assessment. The thesis was written from January 2022 to December 2022. The first phase was to conduct a literature review of the key elements involving the lens crystalline, cataract and eye examination. The second phase was to create the guideline by choosing the suitable and adequate procedures for an eye examination and patient assessment in optometric practice in an optical store. This selection of the content was based on existing valid international and national guidelines, evidence-based literature and the current law considering the optometrist's work.

Results As a result of this thesis, the main issues about the lens crystalline, cataract and management of the cataract are compiled in a literature review based on a literature search. The pre-cataract surgery assessment guideline for Finnish optometrists includes patient history/anamnesis, ocular examination, and management of the cataract. The importance of thorough anamnesis and biomicroscopy skills became on focus in the ocular examination and in the clinical assessment of the cataractous patient.

Conclusions This thesis provides information about the lens crystalline and the cataract, and the guideline can be used as a quick guide to assessing cataractous patients. In the future, the need for eye healthcare services will increase. People are ageing, and ophthalmologists are needed more to manage eye diseases, not to make routine follow-up examinations. Finnish optometrists must be ready to fulfil this growing demand for healthcare professionals.