Contact lenses are medical devices that sit directly on the eye’s surface. Eligibility for contacts depends on a thorough professional assessment of eye health and vision needs. Determining whether you can wear them requires a comprehensive eye examination and a specialized fitting process to ensure both safety and comfort.
Medical Conditions That Rule Out Contacts
Chronic severe dry eye syndrome is the most frequent reason for poor lens tolerance. The lens requires a stable and sufficient tear film to remain comfortable and clear. If the tear film is compromised, the contact lens can exacerbate dryness. This leads to irritation, a gritty sensation, and potential damage to the corneal surface.
Recurring eye infections can also disqualify a person from contact lens use. Wearing lenses, especially without strict hygiene, increases the risk of serious complications like corneal ulcers and permanent vision loss. Severe eye allergies or environmental sensitivities can also make wearing contacts intolerably uncomfortable during flare-ups.
Conditions like advanced keratoconus cause the cornea to thin and bulge into an irregular cone shape. Standard soft lenses cannot effectively vault or correct this irregularity. Corneal irregularities or scarring from previous injury or surgery may also prevent a contact lens from sitting correctly, leading to discomfort and unstable vision.
Specialized Lenses for Complex Vision Needs
High prescriptions, including high levels of nearsightedness or farsightedness, can often be corrected with custom-made soft lenses or Rigid Gas Permeable (RGP) lenses. These lenses are designed to handle powers that fall outside the standard manufacturing range.
High astigmatism is no longer a barrier due to the development of toric contact lenses. Toric lenses feature a unique design with different power zones. They also include a mechanism to keep the lens properly oriented on the eye, ensuring crisp and stable vision.
Presbyopia Correction
Age-related focusing issues, known as presbyopia, can be addressed with multifocal or bifocal contact lenses. These lenses incorporate multiple prescription powers for distance, intermediate, and near vision. This allows for seamless transitions between tasks like driving and reading.
Scleral Lenses
For individuals with highly irregular corneal shapes, such as those with keratoconus, larger scleral lenses are available. These RGP lenses vault entirely over the cornea and rest on the white part of the eye. They create a smooth, fluid-filled surface that provides exceptional comfort and vision correction.
The Required Process for Getting Contact Lenses
The process begins with a comprehensive eye examination. The eye care professional must assess the overall health of the eyes. They also measure the unique physical characteristics required for a safe and appropriate fit.
During the specialized contact lens fitting, the eye doctor measures the curvature of the cornea. They also measure the size of the pupil and the iris to determine the correct lens diameter and base curve. This precise measurement ensures the lens moves properly on the eye, allowing for tear exchange and oxygen flow.
The patient is fitted with trial lenses to evaluate on-eye performance and comfort. The eye care professional checks the lens alignment, movement, and confirms that the vision correction is optimal. A training session is required where the patient learns the correct techniques for inserting, removing, and meticulously cleaning the lenses. The final contact lens prescription includes the brand, power, base curve, and diameter.