Obtaining contact lenses is more involved than getting glasses because lenses are regulated medical devices that sit directly on the delicate surface of your eye. A structured procedure is necessary to ensure the lenses correct vision accurately and fit safely against the cornea. This multi-step process protects your eye health from the initial examination through ongoing maintenance.
The Comprehensive Contact Lens Exam
The first step is a specialized eye examination that goes beyond a standard vision check. This comprehensive assessment evaluates overall eye health to determine if you are a suitable candidate for contact lens wear. The doctor looks for conditions like dry eye syndrome, allergies, or corneal irregularities that could be worsened by wearing lenses.
The exam includes precise measurements of the eye’s surface, which are not part of a typical glasses prescription. Instruments like a keratometer or a corneal topographer map the curvature of your cornea to determine the lens’s “base curve.” These measurements are essential because a lens that is too flat or too steep can cause discomfort, blurred vision, or damage to the corneal tissue.
A contact lens prescription is distinct from a glasses prescription and the two are not interchangeable. Since a contact lens rests directly on the eye while a glasses lens sits about 12 millimeters away, the power needed to correct vision must be adjusted, especially for stronger prescriptions. The contact lens prescription also includes the specific lens brand, diameter, and base curve, which are unique to the lens design and material.
Choosing and Fitting the Right Lens
Once eye health is confirmed and measurements are taken, the next stage involves selecting the specific lens type that best suits your needs and lifestyle. Options discussed include soft hydrogel or silicone hydrogel lenses versus rigid gas permeable lenses, and the replacement schedule (e.g., daily disposable or monthly wear). Special lens designs, such as toric lenses for astigmatism or multifocal lenses for presbyopia, are chosen based on your visual requirements.
The “fitting” process is an evaluation that begins with a pair of trial lenses. These lenses, which match your prescription and initial measurements, are placed on your eyes to check movement and positioning. The eye care professional uses a specialized microscope to confirm the lens is centered correctly and moves appropriately with each blink, indicating healthy tear exchange beneath the lens.
After wearing the trial lenses for a short period (sometimes hours or a few days), you return for a follow-up check. This allows the doctor to assess the lens fit after your eye has adjusted and to evaluate your comfort level and visual clarity in a real-world setting. Only after this successful trial period, which may require trying multiple lens types or brands, is the final contact lens prescription issued.
Learning Insertion, Removal, and Care
For first-time wearers, a hands-on training session is required to ensure safe and hygienic handling of the lenses. This session provides step-by-step instruction on how to correctly place the lens onto the cornea and how to remove it without causing trauma. You will learn to check that the lens is not inside-out, which is typically indicated by a bowl shape rather than a flared edge.
The focus of this training is hygiene, as improper handling is the leading cause of contact lens-related eye infections. You must always wash and thoroughly dry your hands with a lint-free towel before touching your lenses to prevent introducing microorganisms. The eye care professional demonstrates the proper cleaning technique, which involves gently rubbing the lens with a multi-purpose solution and then rinsing before storing it in a case filled with fresh solution.
Never use tap water to clean or store contact lenses or their case, as it may contain bacteria like Acanthamoeba, which can cause severe, vision-threatening infections. The lens case must be cleaned and air-dried daily and replaced every three months to minimize bacterial build-up. Following these explicit care instructions is a requirement for healthy contact lens wear.
Maintaining Eye Health and Renewing Prescriptions
Wearing contact lenses requires an ongoing commitment to eye health and regulatory compliance. You are legally required to have regular follow-up appointments, typically scheduled once a year, to renew your contact lens prescription. This annual visit is necessary because the shape of your cornea and your vision correction needs can shift subtly over time.
During the renewal appointment, the eye care professional checks the continued health of your cornea and ensures the current lens material and fit are still optimal. Wearing an expired prescription means using lenses that may no longer fit your eye’s current shape, increasing the risk of discomfort, corneal damage, or oxygen deprivation, which can lead to complications like neovascularization. The annual exam confirms that your eyes remain healthy and that your lenses provide the best possible vision and fit.