RVLs

RVLs, or Residual Volume Lenses, are a type of specialized contact lens designed for patients with certain eye conditions, primarily keratoconus. Keratoconus is a progressive eye disorder where the cornea, the clear front surface of the eye, thins and bulges outward into a cone shape. This abnormal shape causes distorted vision.

Traditional contact lenses, including soft lenses and even some rigid gas permeable (RGP) lenses, may not adequately correct the vision in advanced keratoconus due to the irregular corneal surface. RVLs are typically rigid gas permeable lenses that are designed to vault over the cone-shaped portion of the cornea. This vaulting creates a tear-filled space between the back of the lens and the irregular corneal surface.

The purpose of this tear layer is to act as a new, smooth optical surface. Light entering the eye passes through the tear layer and then the RVL, which has a precisely manufactured spherical or aspheric front surface. This effectively masks the irregularities of the cornea, allowing for significantly improved vision compared to glasses or standard contact lenses for many patients with keratoconus.

The fitting of RVLs is a specialized process that requires an experienced eye care professional. It involves careful measurement of the corneal shape and curvature to determine the correct lens parameters, including diameter, base curve, and optical power. Patients may require several trial lenses to achieve optimal comfort and visual acuity. While RVLs can provide excellent vision, they require proper care and handling, similar to other RGP lenses.