Contact Lenses: A Comprehensive Guide for Optometry and Ophthalmology Exam Preparation

Contact Lenses A contact lens is a thin, curved, transparent or tinted optical device that is placed directly on the cornea of the eye to correct refractive errors, provide therapeutic benefits, or for cosmetic purposes. Types of Contact Lenses 1. Based on Material Soft Contact Lenses (Hydrophilic lenses) Made of hydrogel or silicone hydrogel Highly comfortable, allows oxygen to pass Used for daily wear, extended wear, or disposable use Rigid Gas Permeable (RGP) Lenses Made of fluorosilicone acrylate Allows oxygen permeability, provides sharp vision Used for high astigmatism, keratoconus, and post-surgical cases Hybrid Lenses Rigid center with soft skirt Combines benefits of soft and RGP lenses Scleral Lenses Large-diameter lenses that cover the sclera Used for irregular corneas, severe dry eyes, and keratoconus PMMA (Polymethyl Methacrylate) Lenses Hard lenses, rarely used now Does not allow oxygen permeability 2. Based on Wear Schedule Daily Disposable Lenses – Worn for one day and discarded Biweekly/Mont…