All eye exams begin with a comprehensive exam that includes a prescription for glasses. Contact lens exam requires the Optometrist or Ophthalmologist to transpose your prescription to accommodate an optimized and comfortable contact lens experience. Your contact lens prescription considers comfort, vision, and daily tasks. Contact lens eye exams usually require a follow up exam for patients new to contact lenses and patients that are experiencing a change in prescription. Depending on the prescription and contact lens type, contact lens exams may require multiple visits to assure patient needs are met. Some first-time or beginners to contact lenses may need several training sessions.
Based on the amount of astigmatism you have, you may need toric lenses to maximize the clarity of your vision through contacts. Toric contact lenses have special markings on them to show if the contact lens is aligning correctly on the eye. If the contact lens is not in alignment, blurry vision may occur and a different contact lens brand or prescription may be needed. This is one reason why glasses and contact lens prescriptions may not be the same. Another reason glasses and contact lens prescriptions may not be the same is that while glasses can be made to very specific degrees of astigmatism (i.e. -2.00 x087), soft contacts come in pre-fabricated amounts of astigmatism (typically -0.75, -1.25, -1.75, -2.25) and offer an axis every 10 degrees (i.e -1.75 x080 or -1.75 x090).
Patients who have high refractive error (especially astigmatism), or keratoconus, or other corneal diseases or degenerations will benefit from a medical contact lens examination. Because the cornea is an important refractive surface, any corneal irregularities can cause blurred images, ghosting, and uncomfortable glare. After careful evaluation of the cornea, a specialty lens can be fitted to improve visual clarity better than what can typically be seen with glasses alone. Rigid lenses can be made very specifically to fit the curvature of the eye. Scleral lenses are specialty lenses that vault the irregular cornea entirely, offering a smooth refracting surface.
A variety of different contact lenses are available to accommodate eye conditions as well as patient preferences. Let's explore these contact lenses that serve a unique purpose and help patients achieve maximum visual acuity. It is vital that you consult a vision physician before using these.
RGP (Rigid Gas Permeable) lenses are rigid contact lenses that allow more oxygen to the cornea by letting the tears flowing under the lenses.
RGP lenses provide very crisp vision, are more comfortable to wear and can be worn longer than most contact lenses.
RGP contact lenses are recommended for people with mild to moderately dry eye, who can wear RGPs longer than standard lenses.
Moreover, these contact lenses are made of materials that don't contain water, so liquids and protein from your tears don't adhere to RGP lenses as readily as they do to other lenses.
Additionally, RGP contact lenses require very little maintenance and, thus, can last for years until a prescription change is needed. Though you can break them, RGP lenses aren't easily torn like soft lenses.
Standard RGP lenses provide excellent vision correction and work wonders with irregularly shaped eyes. Given that they are easier to handle, they are long-lasting and require very little maintenance.
RGP lenses are made from a robust plastic material, with microscopic holes that allow Oxygen to filter through. Most RGP lenses are now made of Silicone, Acrylate, and Fluorine. As such, they retain their shape when you blink, providing sharper vision than soft lenses.
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Hybrid contact lenses combine the wearing comfort of soft lenses with the crisp optics of RGP lenses.
Despite its unique features, only a small percentage of people wear these lenses as they are challenging to fit and cost more to replace than silicone hydrogel and soft lenses.
Hybrid RGP contact lenses are made of a permeable material, walled by an outer fitting zone made of silicone or regular hydrogel soft lens.
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Scleral lenses are large-diameter GP contact lenses that are specially designed to cover your entire corneal surface as well as the sclera.
Scleral lenses functionally replace the irregular cornea with a perfectly smooth optical surface and help correct poor vision caused by corneal irregularities.
Scleral contact lenses are recommended to patients with an irregular corneal surface. This includes patients with pellucid marginal degeneration, Keratoconus, post-penetrating keratoplasty, and corneal scarring.
For some patients, fitting scleral may eliminate or delay the need for corneal transplant surgery. Additionally, scleral lenses are comparatively less drying to other contact lenses and are ideal for patients with ocular surface disease.
Moreover, scleral lens also facilitate healing as well as long-term corneal health, helping to maintain a hydrated and protected corneal surface.
Regular scleral lenses provide the highest amount of clearance between the back surface of the lens and your cornea. The lenses usually range from 18mm to 24mm.
Scleral lenses are made with rigid gas permeable lens materials. So, even if they cover your entire cornea, a healthy amount of oxygen is able to reach the front surface of your eye – which makes the lenses all the more comfortable.
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Scleral lenses are made with rigid gas permeable lens materials. So, even if they cover your entire cornea, a healthy amount of Oxygen is able to reach the front surface of your eye – making the lenses all the more comfortable. Mini-scleral contact lenses are usually of a diameter between 15 to 17.9mm and rest on the front part of your sclera.
Mini Scleral lenses are made with the same rigid gas permeable lens materials as regular scleral lenses. These lenses are inserted with special non-preserved fluid underneath them, which helps trap moisture in all day.
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Disposable contact lenses are lenses that are worn continuously for short periods. Disposable lenses not only offer better hygiene as well as shortening the period for protein deposits to build upon the surface of the eye.
Disposable contact lenses made from silicone hydrogel materials.
There is a wide range of disposable contact lenses: dailies, weekly lenses, bi-weekly lenses, and monthly lenses.
Daily disposable contacts are only worn for a day. They are discarded as natural deposits from your eyes build upon their surface, and cannot be reused.
Disposable contact lenses are packaged in a sterile solution, so if your contact lens isn't beyond its expiry date, they are safe to wear even without rinsing them in an additional solution.
Daily disposable contact lenses are typically thin and fragile and have high water content compared to other types of disposable lenses. They have a thickness ranging between 0.056mm and 0.205mm.
Daily disposables don't do much to help people with eye sensitivity issues. Given that these lenses are very thin, they cannot hold in moisture and dry up quickly.
Biweekly contact lenses are disposable contacts with a scheduled replacement every two weeks. As such, they offer a balance between low maintenance contact lenses and wearing comfort.
Hydrogen Peroxide contact lens solutions are designed to clean, disinfect, rinse and store contact lenses and are especially compatible with biweekly contact lenses as they provide comfort to your everyday wearing.
Biweekly lenses have a central thickness that ranges between 0.061mm and 0.243mm.
Given that biweekly lenses are an in-between to daily and monthly lenses, they have medium ranging compatibility with sensitive eyes.
Monthly lenses are disposable lenses that wearers need to change after every month.
Monthly contact lenses need to be disinfected regularly to ensure safe wearing. Using a protein removal solution will not only clean the protein discharge on the surface of your eye but will also make them more comfortable to wear.
Monthly contact lenses are thicker than disposable lenses, which makes them more durable and long-lasting as well as more resistant to drying out. Biweekly lenses have a central thickness that ranges between 0.061mm and 0.243mm.
Monthly contact lenses are incredibly compatible with sensitive eyes. Given that they are thicker to standard contact lenses, they can hold in moisture, which helps offset eye irritation.
After taking careful measurements and determining the health of your eyes, your doctor will select and choose a pair of trial lenses that would work best with your eyes. A trial lens is included with every contact lens exam with us. After placing the lenses on, the doctor exams the fit, movement and tearing in your eye. The doctor’s goal is to confirm good vision, fit, and comfort. If the lenses do not appear to be a good fit, the lens or prescription can be adjusted and another lens fitted. Once the lenses are fit, you can keep the trial pair and your contact lens prescription will be finalized and ordered. It is common to schedule a follow-up appointment to check that your updated or new contact lenses are comfortable, fitting properly, and providing good vision.
