Spectacle Frames

a.         Full Frames
                       
Full frames are the most common type of spectacle frames in the market. They are called full frames, as the rim of the frame covers the entire lens all around. Full frames can be of various material, such as Nickel Alloy, Titanium, Plastic, and Stainless Stell. Full Frames are considered to be a safer choice for children, as the lenses are held securely in place, and of less chances of lens breakage.

b.         Rimlon (Half) Frames
           
Half frames are gaining popularity lately, and it encompasses the frame usually on the upper half of the spectacles, and the lens is held in place by nylon on the lower half. This type of frames are also not as prone to lens breakage compared to rimless frames, but the lens may chip at the edges, when one is not careful during the bending or adjustment of the spectacles. Plastic lenses are the choice of lenses for this type of frames, as it is light, and more suitable to be supported by the nylon string. Sometimes, half frames can be found with the frame at the bottom half, and the nylon on the upper half.
                       
c.         Rimless Frames

Rimless frames are a popular choice of frames, as it gives the illusion of not wearing the spectacles. This is because there is no frame surrounding the lenses. The lenses are held in place by screws or plastic inserts that are fitted into holes that have been drilled into the lenses. Rimless frames are more prone to lens breakage, as drilled lenses loses their hardy integrity, and therefore can crack or break easily if subjected to pressure, knocks, or dropped. Plastic lenses are the type of lenses used for rimless frames, as they can be subjected to drilling without shattering or cracking as glass does.

d.         Plastic Frames

Plastic frames are mainly made entirely out of plastic, and are considered to be lighter, compared to their framed counterparts. Plastic are also suitable for people with skin sensitivity, where they can get irritation when their skin gets into contact with corrosive metal. Plastic do not corrode as metal do. Plastic frames can be made entirely of plastic, or can be in combination with metals, with the frame made of plastic, and the temples made of metal, or vice-versa. Plastic frames have an added advantage of being able to conceal the thickness of the lenses. Plastic lenses are the lenses of choice for plastic frames, as they are easily fitted into the frame, compared to glass lenses.

e.         Frames with Clip-on Sunglasses

These spectacle frames comes with clip-on sunglasses that matches with the frame itself. They are popular with motorists, as the clip-on can be easily attached when driving. The clip-ons can come as normal sunglasses lenses that provides UV protection, or as Polaroid lenses that can filter the sun’s glare. This type of frames are usually in metal material, but sometimes plastic frames with clip-ons can also be found.

Ophthalmic Lenses

a.         Plastic Lenses
                       
Plastic lenses are very popular, as they are light, and does not break easily. These lenses come in a variety of refractive index, such as 1.5, 1.56, 1.61, 1.71, and 1.74. The refractive index is in fact the density of the lenses. The higher the refractive index, the thinner the lenses are. Therefore, 1.74 index lenses are thinner, compared to 1.5 index lenses.
                       

Glasses lenses are thin, and more scratch resistant than plastic lenses. They exist in higher refractive indices compared to plastic lenses. Therefore, they have gained popularity with the highly myopic individuals. The glass lenses exist in refractive indices of 1.5, 1.7, 1.8, and 1.9. When comparing a high index plastic lens with a same index glass lens, they are similarly thin, but the glass lens is cheaper compared to their plastic counterpart. The downside of glass lenses is that they are prone to shattering and breakage when subjected to pressure or dropped.

This special type of lenses is the most impact resistant lenses that is available in the market. Polycarbonate lenses are suitable for individuals who participate in contact sports, vigorous activities, occupations that require protective eyewear, as well as children. In the USA, polycarbonate lenses are considered the lenses of choice for children, as the lenses are very safe for children to use.

When a person reaches 40 years old and above, the focusing muscles inside the eye will start to deteriorate. Starting from this time, a separate prescription will be needed for reading and distance vision. Progressive lenses eliminate the need for 2 pair of glasses, incorporating both reading and distance, and even intermediate vision. Progressive lenses are available in many models and types. Your optometrist will be in the best position to recommend the type of progressive lenses that is suitable for you.

The top of the lens is used for distance vision, while the power gradually lowers till the intermediate corridor. This intermediate corridor caters for vision between 60cm to 4 metres away. Below the intermediate corridor is the reading zone. The reading zone is located at the bottom of the lens. Therefore, when one needs to read, he/she will need to look slightly down, through the bottom of the lens. If he/she needs to look at something far away, he/she will just need to look straight ahead. There are two zones on extreme left and right of the lens that is not usable. When viewed through these zones, vision will be blur.

Bifocal lenses are used in a similar way as compared to progressives. The majority of the lens is used for distance vision, and there is section at the bottom portion that is used for reading. The reading segment can exist as round, flat-top, e-lined, or blended. One will need to view down, and look through the reading segment to read. Otherwise, he/she will just need to look out of the reading segment to view distance objects.

The drawback of bifocal lenses is that there is no intermediate zone. Therefore, objects at 60cm to 4 metres may appear blurry.

Sunglasses

When out in the open, especially when participating in outdoor activities, it is important to protect your eyes from the glare of the sun. The sun emits a wide range of light rays, which includes Ultra-Violet (UV) rays. UV rays comes in the form of UV-A, UV-B, and UV-C. UV-C is normally absorbed by the earth’s atmosphere, and therefore, UV-A and UV-B are able to penetrate the atmosphere to the surface of earth. The eyes are just like the skin. The eyes need protection from UV radiation, as too much exposure to the sunlight can result in tissue changes of the eye.

Excessive UV exposure can result in eye conditions such as cataract, pterygium, photokeratitis (sun-burn of the cornea), cancer of the skin around the eye, and cornea degenerative changes. UV radiation can also penetrate deeper into the eye and cause damage to the retina and its surrounding tissues.

Wearing a pair of sunglasses which can effectively block out harmful UV rays will prevent or slow down the development of the above eye conditions. Sunlight can reflect on water, snow, car bonnets and sand, and therefore, protection is required not just in the open, but at all environments when the sunlight is reflecting on various surfaces.

Contact Lenses

a.         Soft Conventional Contact Lenses
           
This type of contact lenses is used for 1 to 1.5 years, if they are well maintained. They are generally of lower water content and tougher in material, compared to their disposable counterparts. Conventional contact lenses are available in a greater variety of sizes that can fit more eyes, compared to disposables. Therefore, they can be considered to be tailored made lenses for the eye.

The drawback of conventional contact lenses is that the lens allows limited amount of oxygen to pass through itself, thereby supplying insufficient oxygen to the eye. However, using conventional contact lenses in moderation will allow the cornea to remain healthy. This means that conventional contact lenses should be worn not more than 8 to 10 hours a day, and preferably 1 to 2 days a week of not wearing the lenses to let the eye ‘breathe’.
                       
b.         Soft Disposable Contact Lenses

Disposable lenses are worn for a certain fixed period, before it should be discarded for a fresh pair of lenses. They are available in modality such as daily disposables, fortnightly disposables, and monthly disposables. Disposable lenses are sold in boxes, in which, each box usually contains 30 pieces of lens for daily disposables, and 6 pieces of lens for fortnightly or monthly disposables.

Disposable lenses are comfortable to wear, as most of them are thin, and contains high water content. High water content provides the initial comfort, and allows oxygen to flow through the lens via the water molecules. However, after long hours of wear, the water from the lens may evaporate, and hence will draw water from the cornea to re-hydrate the lens. This may worsen the wearer’s dry eye problems.

Disposable lenses are available in limited curvatures, as well as limited powers in 0.50 steps when above -6.00D. Therefore, disposable lenses may not fit the eye as well as conventional lenses. Your optometrist will need to do a trial fitting of the lens for you to determine the most suitable lens for you. Ill fitting lenses are initially comfortable, but may eventually result in dry eyes, transient blur vision, and discomfort.

Newer lenses that have materials that allow more oxygen to the eye are available. They are more suitable for long hours of wear, but trial fitting is still required to determine if you are suitable to wear the lenses. Disposable lenses are the most popular type of lenses in the market. This may be attributed to the high level of marketing, as well as the promise of comfort, by the manufacturers.

c.         Rigid Gas Permeable Conventional Contact Lenses

RGP lenses are smaller, and harder lenses that have been around for decades. RGP lenses are mainly used by a group of wearers with high powers. This is due to the fact that RGP lenses can be tailored made for each individual eye, to correct the power accurately and to align itself perfectly with the cornea curvature.

Good fitting RGP lenses moves slightly in the eye when it blinks. This movement facilitates tears exchange between the rest of the eye and the underneath of the lens. Tears bring oxygen to supply the area of cornea that is underneath the lens. Tears exchange is minimal with ill fitting soft lenses.

The latest RGP lenses sport the newest material in the market that allows oxygen to freely pass through the lenses. Therefore, RGP lenses with the newest material are suitable for longer hours of wear, or even extended wear (overnight).

The main drawback of RGP lenses is the initial comfort. Due to its rigid nature, upon initial insertion of the lens, the wearer will immediately feel the lens inside the eyes. This can be described as itchy, or even uncomfortable. This is due to the eyelids moving on the edge of the lens when blinking. The eye gets used to the lenses in 1 to 2 weeks, whereby the awareness of the lens will gradually disappear.

d.         Cosmetic / Prosthetic Lenses
           
Cosmetic lenses are available in a wide variety of colours. These lenses are inked with colours on the surrounding of the lens, and a clear zone at the centre for the wearer to see through. Cosmetic lenses are available in a wide variety of colours to suit the wearer. They are popular with young teenagers who wish to temporarily change the colour of their eyes. However, care must be taken not to over-wear the lenses, as the coloured lenses may retard oxygen from entering the cornea. Over-wear may also lead to potential eye infections.

Prosthetic lenses are made to mimic the colour of the normal iris (eye) colour. They are usually used to conceal cornea scars that are usually whitish or yellowish. If a person is blind from the eye due to entire cornea scarring, then he/she can use an opaque lens which mimics the colour of the other eye. If the person has a small scar at the corner of the eye, but still sees well through it, he/she can use a prosthetic lens with a clear centre to cover the scar and correct the vision at the same time.

Contact Lens Solutions

a.         Surfactant Cleaner

This is actually soap for the contact lens. Surfactant cleaning removes debris, oil, mucus and dirt that are adhered onto the lens.  It is important to surface clean the lenses to prevent the debris from building up and causing discomfort and irritation to the wearer. Most contact lens wearer forgoes the surface cleaning when they use either the Multipurpose solutions or Hydrogen Peroxide Systems, which will only disinfect the lens but not remove debris from it. To properly remove debris from the lens surface, one or two drops of the surfactant cleaner will need to be applied on the lens. The lens should be rubbed by the fingers for at least 30 seconds on each side.

b.         Multipurpose Solutions (MPS)

The MPS is an all-in-one solution for contact lens wearers. Most MPS are capable of cleaning, disinfecting, rinsing, storing and even lubricating the lens while in the eye. Most MPS are now marketed to be in a no rub formula. However, it is more advisable to rub the lenses for at least 30 seconds on each side to remove the surface debris with a few drops of the MPS, before rinsing and storing with the MPS. In this case, the MPS is the surfactant cleaner. But it may not be as strong as the stand-alone surfactant cleaners. Therefore, conventional lens wearers should use a separate surfactant cleaner for better removal of surface debris.

The MPS can also be used for rinsing and storing of the lenses. When the lenses are soaked in MPS, the lenses are disinfected. Therefore, it is important to soak the lenses in MPS after wear for the stated number of hours on the MPS instructions. Before putting the lenses back into the eye, you can either use the MPS or saline to rinse the lens again. Using saline is more suitable for wearers with sensitive eyes.

c.         Hydrogen Peroxide Systems

Hydrogen Peroxide systems are very effective disinfecting solutions. The contact lenses should be rubbed clean by a surfactant cleaner, before soaking into the hydrogen peroxide solution. The hydrogen peroxide will disinfect the lenses from any micro-organisms. Neutralisation of the hydrogen peroxide either comes in the form of a tablet, a platinum ring, or another solution, varying with different brands.

The tablet is placed into the solution just after the lenses are placed in. The tablet will slowly dissolve and neutralise the solution to become water. Usually, a change in colour of the solution will indicate that it has been neutralised. The platinum ring exists in the lens case, and will automatically start to neutralise the solution when the case is closed. As for the neutralising solution, adding it into the hydrogen peroxide will begin neutralisation process.

Do note that there are a certain number of hours for effective neutralisation. Please check the instructions on the solution box, bottle or inserts for the exact instructions.

d.         Protein Removal

Protein removal exists in tablet form and also in solution form. Protein removal is important in removing the proteins that have been stuck onto the lens. This protein originated from the tears of the eye, and can become adhered on the lens surface. The protein removal contains enzymes that will break down the protein, and allow the protein particles to be easily removed by rinsing. It is important to do protein cleaning at least once every two weeks.

These eye drops helps to wet the lens while it is in the eye. Contact lens wearers with drier eyes may find that their eyes gets dry, irritated, uncomfortable or even blurry after a few hours of wear. They usually alleviate this problem by blinking the eyes. Contact Lens Lubricating Eye drops provide better relief compared to blinking.

This type of eye drops is suitable for individuals with dry eyes, which can be worsen by long hours of reading or computer use. They can also be used by contact lens wearers, but some eye drops are not suitable for use while the contact lens is in the eye. This is because the drops may be thicker (more viscous) compared to regular lubricating lens drops, or these drops may contain some substances that may adhere on the lens.