(Top) 0.50 confirmation set; (Middle) trial lens box, including pinhole and occluder; (Bottom) Snellen chart<unk>  is a technique to determine the combination of lenses that will provide the best corrected visual acuity (BCVA). It is a clinical examination used by orthoptists, optometrists and ophthalmologists to determine a patient's need for refractive correction, in the form of glasses or contact lenses. The aim is to improve current unaided vision or vision with current glasses. Glasses must also be comfortable visually. The sharpest final<unk>  is not always the final script the patient wears comfortably.
Subjective refraction
Urinometer
Scanning laser polarimetry
Corneal topography
Exophthalmometer
Intraocular lens power calculation
Dosimetry
Corneal pachymetry