Custom contact lenses are the best option for those who can wear regular contact lenses because of problems like too much astigmatism and irregularly shaped eye. You can also try custom made contacts if normal contacts are uncomfortable or cause vision problems.
Custom contact lenses are available in both soft lens and rigid gas permeable materials. They may provide more comfort and sharper vision than regular GP or soft lenses.
Custom Gas permeable contact lenses
Many of the eye care doctors believe that gas permeable contact lenses provide sharper, more crisp vision than soft contacts. However, this is true for only certain types of astigmatism.
For some people, it is difficult to get used to the gas permeable contact lenses as they are designed in such a way that they create a slight gap between the eye surface and the edge of the lens. This gap allows tears to flow behind the lens when you blink to provide more oxygen to the retina. The interaction between the eyelid and the edge of gas permeable lenses and the movement of the lenses during the blink can make them uncomfortable for the wearers.
It may be impossible to completely fit the eye with the gas permeable lens for the people with irregularly shaped corneas, therefore. The lens doesn’t remain at the centre of the eye
To overcome these limitations and provide more people with clear, comfortable vision with gas permeable lenses, manufacturers use modern technology to craft customized gas permeable lens options
Lens designs and eye measurements for regular gas permeable contact lenses
The lens manufacturing and fitting process for gas permeable custom lenses is different from regular gas permeable lenses in two ways; design of the lenses and eye measurement.
Eye care practitioners that measurements of the curvature of the front of the cornea with an instrument known as keratometer. It uses light reflections from the cornea to determine the flattest and the steepest meridians of the eye.
The curvature of the regular gas permeable lens is based on three measurements; the curve of the flattest meridian, the steepest meridian of the cornea and the orientation of the flattest meridian. The eye care practitioner chooses the curves based on these measurements to apply to the back of the gas permeable lens for a perfect fit.
Lens designs and eye measurements for Gas permeable custom lenses
Lens designs and eye measurements for custom gas permeable lenses are way more complex as compared to that of regular lenses.
Instead of three measurements, the eye care practitioner uses as an instrument called a corneal topographer to measure the curvature from several thousand reference points on the eye.
The data collected from corneal topographer give a detailed map of the curvature of the eye which is then used to design a custom, multi-curved lens surface that fits on the surface of the cornea to a great extent.
The custom gas permeable lens is made of newer gas permeable lens materials that allow more oxygen to reach the cornea directly through it, therefore, it does not need tears pumping from underneath the lens.
For whom gas permeable custom contact lenses are the best?
Anyone who wants to improve their vision and has found regular contact lenses uncomfortable can go for gas permeable custom contact lenses.
Custom gas permeable lenses are an excellent solution for unusual corneal curvature or keratoconus as they can be crafted to fit unusual corneal surfaces.