A contact lens fitting is a specialized process that goes beyond a standard eye exam. Unlike a routine vision check, which determines the power needed to correct your sight, a fitting focuses on the physical relationship between the lens and the surface of your eye. Since a contact lens is a medical device resting directly on the cornea, an improper fit can compromise eye health, leading to discomfort, irritation, or corneal damage. The fitting ensures the lens matches the unique contours of your eye, promoting optimal vision and long-term ocular well-being.
The Professionals Who Conduct Fittings
The majority of routine contact lens fittings are performed by Optometrists, who hold a Doctor of Optometry (OD) degree. Optometrists are primary eye care providers trained to examine eyes for vision and health problems, diagnose and treat many eye conditions, and prescribe and fit corrective lenses, including contacts. Their training includes the detailed measurements and assessments required to ensure a healthy and comfortable lens fit.
Ophthalmologists, who are medical doctors (MDs) specializing in eye and vision care, are also qualified to perform fittings and prescribe lenses. Their practice often centers on complex medical and surgical treatments for eye diseases. Patients with generally healthy eyes often find that an optometrist is the most common and accessible professional for their fitting and ongoing contact lens management.
Practical Locations for Contact Lens Fittings
Private optometry practices often provide the most personalized fitting experience and greater continuity of care. These independent offices offer specialized attention for complicated fittings, such as those involving rigid gas permeable or scleral lenses. Building a long-term relationship with a single doctor is beneficial for tracking subtle changes in eye health related to lens wear.
Optical retail chains and big box stores with in-house vision centers offer convenience and flexible scheduling. These locations are efficient for routine fittings of common soft lenses and may provide bundled pricing when purchasing an annual supply. Doctors at these centers are fully qualified to conduct the necessary measurements and evaluations, though personalization may vary.
For fittings involving highly complex conditions, such as severe dry eye or corneal irregularities like keratoconus, a medical center or hospital-affiliated eye clinic may be the appropriate choice. These settings often have access to advanced diagnostic equipment and specialists who focus exclusively on therapeutic or custom-designed contact lenses. Selecting a location should depend on the complexity of your vision needs and your preference for convenience versus highly specialized care.
Navigating the Fitting and Trial Process
The contact lens fitting is a procedure separate from the standard eye exam, focusing on the specific dimensions of the eye’s surface. During the fitting, the doctor uses a keratometer or corneal topographer to precisely measure the curvature of the cornea, which dictates the lens’s base curve (BC). Measurements also include the diameter of the cornea and pupil to ensure the lens covers the required area without causing irritation.
Based on these physical measurements and your visual needs, the doctor selects diagnostic or trial lenses, which you will wear in the office. This allows the doctor to assess the lens’s movement, centering, and oxygen permeability on your eye. The doctor will also evaluate the tear film, as dry eye can significantly affect lens comfort and wear time.
You will typically leave the office with trial lenses to test for a specified period, often one or two weeks, to confirm comfort and visual acuity in real-world conditions. A follow-up appointment is required before the prescription is finalized. During this visit, the doctor re-examines your eyes with the lenses in place to ensure they are not causing long-term harm to the cornea or conjunctiva.
Securing and Using Your Contact Lens Prescription
The final output of the successful fitting process is a comprehensive contact lens prescription, which is distinct from a glasses prescription. This document contains specific parameters that cannot be determined by a standard eye exam. The prescription must include the brand name of the lens, the power (Sphere/PWR), the base curve (BC), and the diameter (DIA).
For patients with astigmatism, additional measurements like Cylinder (CYL) and Axis must be included; multifocal lenses require an Add power (ADD). Federal regulations mandate that the prescriber must provide you with a copy of your complete contact lens prescription upon completion of the fitting.
This legal requirement allows you to purchase lenses from any seller, including online retailers. The prescription has an expiration date, usually one year from the date of issue, which ensures you return for regular eye health checks.