This tool converts a patient’s eyeglasses prescription, determined by a process called refraction, into a suitable contact lens prescription. It accounts for the difference in vertex distance the distance between the corrective lens and the eye present with eyeglasses versus contact lenses. For example, a -3.00 diopter eyeglass prescription might translate to a -2.75 diopter contact lens prescription due to this difference. The specific calculations involved consider factors like the eyeglass prescription power, the vertex distance of the eyeglasses, and the estimated fitting characteristics of the contact lens.
Accurate conversion is essential for clear and comfortable vision with contact lenses. Without proper compensation for the vertex distance, the contact lens power would not be optimal, potentially leading to blurred vision or eye strain. This process has become increasingly important with the advent of higher-powered prescriptions and the wider availability of various contact lens modalities. Historically, conversion tables and manual calculations were used; however, dedicated calculators now offer greater precision and speed, simplifying the fitting process for eye care professionals.
