Facts about Lens

A common mistake people often make when buying eyeglasses is not spending enough time in response to the demand for thinner, lighter eyeglasses, have introduced high-index plastic lenses. The index of refraction (or refractive index) of an eyeglass lens material is a number that is a relative measure of how efficiently the material refracts (bends) light, which depends on how fast light travels through the material. In other words, for a given eyeglass lens power, a lens made of a material with a high refractive index will be thinner than a lens made of a material with a lower refractive index.

The Abbe value (or Abbe number) of a lens material is an objective measure of how widely the lens disperses different wavelengths of light as light passes through it. Lens materials with a low Abbe value have high dispersion, which can cause noticeable chromatic aberration-an optical error visible as colored halos around objects, especially lights. Abbe values of eyeglass lens materials range from a high of 59 (crown glass) to a low of 30 (polycarbonate). The lower the Abbe number, the more likely the lens material is to cause chromatic aberration.

In addition to choosing a lens material that has a high index of refraction, another way to give your lenses a slimmer, more attractive profile is to choose an aspheric design. Spheric design- where the lens curvature changes gradually from the centre of the lens to its edge, because aspheric lenses are flatter, they cause less unwanted magnification of the wearer's eyes, for a better appearance. In some cases, aspheric designs also improve the clarity of the wearer’s peripheral vision. Most high index plastic lenses are made with aspheric designs to optimize both the appearance and the optical performance of the lenses.

All plastic and high-index plastic lenses require a factory-applied anti-scratch coating for adequate lens durability.

Anti-reflective coating: An anti-reflective (AR) coating makes all eyeglass lenses better. AR coatings eliminate reflections in lenses that reduce contrast and clarity, especially at night.

UV-blocking treatment: Cumulative exposure to the sun’s harmful ultraviolet (UV) radiation over a person’s lifetime has been associated with age-related eye problems including cataracts and macular degeneration.

A moth's eye and lotus leaf were the inspirations for an antireflective water-repelling, or superhydrophobic, glass coating that holds significant potential for lenses.

Facts about Frames

Frames not only suite our style and fitted to the shape of our face, but also to be suite to our perception and life style.

It is important to understand the importance of durability, consistency of finish and manufacture, company reliability and style appeal.

These qualities are found in Ransumi’s frames. Other consideration are shape of the face, skin tone, life style, lens designs, lens features which Ransumi takes care.

Lens can made aspheric or high-index designs for the more difficult perceptions. This design made with a much flatter carves, so there is lens thickness in the lens, giving the eyewear a slimmer more flattering profile.

For perception over -2.50 a smaller frame should be consider to avoid edge thickness.

When choosing a rimless mounting high index lens should be used, having adjustable nose pad rather than fixed taken adjustment easier and keep the heavy lens sitting in the correct position.

Today smaller fashionable frame are design to hold (Short Corridor) progressive lens with a more compact designed, provides the larger reading area.

Ransumi’s eyewear emphasize the best personal future, complimenting the shape and coloring of your face.

Our frame fit properly to be comfortable and allow you to see through the lenses at the optical centre of optical vision.

Facts about Sunglasses

Yet this simple and stylish accessory can protect your eyes from a host of conditions caused by ultraviolet rays:

Skin Cancer: Up to 10 percent of all skin cancers are found on the eyelid.

Cataracts: The World Health Organization reports that, worldwide, approximately 900,000 people are blind because of cataracts-cloudiness in the lens of the eye-triggered by UV exposure.

Macular Degeneration: Over time UV light may play a role in damaging the macula lutea (an area of the eye with millions of light-sensing cells, which allow us to see fine details clearly), potentially leading to blurriness and vision loss.

Pterygium: Pterygium: This abnormal growth of tissue-also called surfer’s eye-may progress slowly from either corner across the white part of the eye, possibly leading to inflammation or disturbance of vision.

Photokeratitis: Essentially a sunburn of the eye, it’s temporary (healing within 48 hours) but can be painful, causing blurred vision, light sensitivity and the sensation of having sand in your eye.