A contact lens is a medical device that, when placed correctly, refracts the light entering your eye so it is properly focused on your retina. Contact lens wearers need to have their eyes measured and fitted to ensure they are receiving the best possible vision correction with their lenses.

Before handling contacts, you should wash and dry your hands. This helps prevent eye infections.

Soft Contact Lenses

Soft contact lenses are comfortable, safe and effective for correcting a wide range of sight impairments. Their flexibility means they can be used to address both short sightedness (myopia) and far sightedness (hyperopia).

Most disposable soft lenses are available in daily, two-weekly and monthly designs that must be removed at night and cleaned with a recommended cleaning solution before wearing again. These solutions often contain preservatives like benzalkonium chloride and benzyl alcohol, but preservative-free options are also available.

When first using contacts, it is common to experience a brief period of irritation that fades quickly as the lens is gently positioned on the eye. This is caused by a slight difference in pH and salinity between the lens solution and your tears, but can be minimised by following a few simple guidelines for insertion and removal. These include starting with the same eye each time, choosing a finger to hold the lens on and not pinching the lens between your thumb and index finger which may scratch the cornea.

Hybrid Contact Lenses

Unlike hard contact lenses that are completely rigid, hybrid contacts have a soft outer rim that allows for a flow of tears and oxygen to the cornea. This allows patients with irregular cornea conditions to comfortably wear hybrid contact lenses. The latest generation of hybrid contact lenses like the SynergEyes UltraHealth lens combines a hard GP center with a soft outer skirt. This combination is the biggest leap forward in contact lens fitting for decades.

The soft skirt keeps the lens centered over the visual axis regardless of where the cone is located on the cornea or how large it is, reducing visual distortion and offering superior vision. The design also prevents dirt from accumulating under the lens or popping out unexpectedly.

We encourage our patients to hold a hybrid lens in their hand on the first visit, which helps them understand the technology and takes away the apprehension about wearing a hard contact lens. We also recommend that you rinse and store your hybrid lenses in fresh disinfecting solution, not tap, distilled or bottled water (this is where eye infections start).

Rigid Gas Permeable Contact Lenses

Rigid gas permeable (RGP) contact lenses are made from firm plastics that allow oxygen to pass through them. This allows the cornea to have a continuous supply of oxygen and helps reduce irritation caused by protein deposits on soft contact lenses. RGPs are also less prone to tear-offs and provide sharper, crisper vision.

GP lenses can be made from a variety of materials with differing oxygen permeability, measured in Dk units. These measurements are not universal and can be affected by experimental procedures used to determine permeability.

The most common rigid contacts are made of polymethyl methacrylate, or PMMA. These are the contact lenses of choice for patients with keratoconus as they are very stable and offer superior visual quality. Other hard contact lens materials include cellulose acetate butyrate, silicone acrylate and pure fluorocarbon. These new plastics are more durable and able to withstand greater heat and dryness than older materials. They can be worn overnight for extended periods, depending on your eye care professional’s evaluation of your tolerance to this level of wear.

Aspheric Contact Lenses

Aspheric contact lenses have different curvatures on their surfaces and flat edges that help to focus light more precisely. This can improve your vision, especially when using the lenses for tasks that require you to shift your focus between near and far objects.

The flat edges of the aspheric lens also help reduce spherical aberration, which can cause blurry images. This can be useful for patients who have astigmatism.

Some aspheric lens designs use a series of conicoid surfaces that mathematically resemble ellipses, while others have a base curve that flattens from the central apex to the periphery. A topographer can help identify which lens design best matches the corneal asphercity of a patient’s eye. This helps optimize the fitting relationship and on-eye performance. The resulting optimal visual result can minimize spherical aberration, which may reduce scotoma, a ringed blind spot.3