Anti-Reflective Coating ( AR coating / HMC )
This coating can help improves vision, reduces eye strain and make for a nicer look. These benefits are due to the ability of anti-reflection coating to virtually eliminate reflections from the front and back surfaces of your eyeglasses lenses, results in vision clarity improvement and visual perception specially on night time driving or people with high prescriptions.
Ultraviolet treatment (UV 400 nanometre) is extremely important to protect eyes from the damaging effects against harmful UV sun rays which can accelerate the development of cataracts and macular degeneration.
Blue Coat / Blue Violet
Blue coat or blue light filter blocks the harmful portion of blue light and allows the healthy portion of blue light to pass through your eyeglasses lenses.
Lens index is a number that describes how thick or thin your lenses are. Prescription glasses with a higher lens index offer thinner & lighter lenses. The other way around, lower lens index will have thicker lenses.
Range of lens index
-- Standard Index 1.50
-- Mid-Index 1.56
-- High Index 1.61, 1.67, 1.74
What affect lens thickness?
-- Index The higher the index, the thinner the lens.
-- Prescription For the same index, the higher the prescription power, the thicker the lens is.
-- Pupillary Distance The higher number of pupillary distance (distance between two pupil center) the lens will be thinner.
-- Frame size For the same prescription and lens index, the larger the frame chosen, it will utilize the thicker part of the lens at the side.
Recommendation of lens index
-- Index 1.56 is ideal for power less than myopia -2.00
-- Index 1.61 is ideal for power less than myopia -4.00
-- Index 1.67 is ideal for power less than myopia -6.00
-- Index 1.74 is ideal for power less than myopia -8.00
Note : However, please take note that astigmatism power might add extra thickness on the lens. If you are very particular about lens thickness, you may seek for your Optical Professional for more explanation.
Sample of lens thickness effect vary by power & index
Note : Lens edge thickness measurements are taken from optical uncut lens of diameter 65mm. Thickness result vary depending on your pupillary distance, frame size (lens width) and other prescription values.
Spherical lenses have a front surface that is spherical, meaning has the same curve across its entire surface.
Aspheric lenses design for a thinner curve and lighter in weight for glasses. Flatter peripheral curvatures than a regular spherical lens reducing magnification effect of the eyes which improves cosmetic appearance, and also reduce distortions that occur when looking away from the centre of the lens.
Hoya Nulux aspheric lenses renowned for the durable quality, thinner, easy-to-clean and scratch-resistant. It provides optimised visual performance and wider visual field.
Pupillary Distance (PD)
Pupillary distance measures the distance between the center of your eye pupils. This is an important number to ensure your both eye pupils match up with the prescription lenses optical centre.
How to measure pupillary distance by yourself?
Note : Measure your pupillary distance up to 3 times to ensure the number is accurate and consistent. If you are very particular about pupillary distances measurement accuracy, or noticed your distance of right eye and left eye towards nose bone are not same, you may seek for your Optical Professional for further assistance.