Rigid Gas Permeable contact lenses fitting
BSc, MSc, PhD candidate of optometry
Rigid Gas Permeable (RGP) contact lens is one of the selective choices for correcting the corneal astigmatism and the visual improvement; especially in patients with keratoconus. the ability of successfully fit RGP contact lenses is often what separates the good contact lens practitioner from average one. The intended relationship between the cornea and the back optic zone of the lens will depend on the fitting philosophy adopted. There are two Extreme positions that can be adopted: Lid attachment and Interpalpebral. Most lenses these days are fitted for an ‘alignment’ fit that is some way between the two extremes. It should be emphasized that there isn’t just one way of fitting RGP lenses, and the short history of rigid lenses contains examples of very flat and very steep. The idea is to fit the back optic zone in close alignment with the front surface of the cornea, with a uniform, thin tear film between the two. Overall mild fluorescein clearance with slit lamp examination should be achieved in align fit. The goal of a RGP contact lenses fitting is to provide good vision, comfort and normal physiological ocular response while wearing lenses. In addition to these goals it is also necessary to achieve an adequate wearing time.
Theses lenses make better quality of vision with correcting refractive errors especially high astigmatism. Therefore, it's important to know how to fit the RGP lenses to achieve optimal vision.