What contact lenses will suit you best
Each patient requires individual selection of contact lenses. Only professional ophthalmologist can help you to select the most suitable contact lenses according to your personal characteristics.
The following parameters of eye cornea should be considered in the process of selection of contact lenses:
1.The curvature of eye cornea is one of the key parameters, used by professional ophthalmologist in the process of selection of contact lenses.
For contact lenses this parameter is called as base curve or base curve radius - the curvature of the central part of the back surface of the lens. It is marked as BC or BCR in the medical prescription or on the lens package.
The base curve radius is responsible for lens fitting. If it has been selected incorrectly and does not match with the shape of the cornea, the user can experience discomfort while wearing contact lenses.
The base curve radius is measured in millimeters. The middle range varies from 8 to 9 mm. The most common base curve radius is 8.6 mm. With the increase of the base curve radius the lens fitting becomes more flat.
The base curve radius can be measured with the help of autorefractometry.
2.The diameter of the cornea. It is measured to obtain the value of lens diameter.
Contact lens diameter is the distance between two edges of the lens, measured through the center in millimeters. The average values of lens diameter vary from 13.0 to 15.0 mm. It is marked as DIA (mm.) or D(mm.) in the medical prescription or on the lens package.
3.Sphere, optical power - an indicator of visual acuity and deviations, expressed by the plus or minus values (+/-). Optical power is measured in diopters and marked as Sph, Pwr, POWER. For right and left eyes the values may be different.