Category Archives: Glossary

Varifocal lenses Varifocal lenses – Multifocal lenses with a seamless gradient of varying optical powers, allowing clear vision at different distances without the visible lines found in bifocal or trifocal lenses. Varifocal lenses are often used to correct presbyopia, providing a more natural visual experience for activities ranging from driving to reading.

Prism lenses Prism lenses – Specialised lenses used to correct double vision (diplopia) by altering the way light enters the eye, helping to align the images seen by each eye into a single, clear image. Prism lenses are often prescribed for people with certain eye alignment disorders, such as strabismus.

Glasses cylinder The cylinder (CYL) value indicates the amount of lens power needed to correct the uneven curvature of the cornea. The CYL power can be written in + or – Cyl. The CYL power will always have an axis direction. This value is combined with the axis to properly align the corrective power in …

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Glasses axis A component of an eyeglass prescription for astigmatism, the axis is a number between 0 and 180 degrees that specifies the orientation of the cylinder correction. It ensures that the lenses are positioned correctly to compensate for the irregular shape of the cornea, helping to provide clear vision.

Eye floaters Small, shadowy shapes that appear in your field of vision, often described as spots, threads, or cobwebs. Floaters are usually harmless and result from the breaking down of the vitreous humour, the gel-like substance inside the eye, which occurs naturally with age. However, a sudden increase in floaters, especially when accompanied by light …

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Ophthalmologist Ophthalmologist – A medical doctor specialising in eye care, capable of diagnosing and treating eye diseases, performing eye surgeries and prescribing glasses and contact lenses. Ophthalmologists undergo extensive training, including medical school, residency and often further specialisation in specific areas of eye care.

Phoropter Phoropter – An instrument used by eye care professionals during an eye exam to measure refractive error and determine the best prescription for glasses or contact lenses. The phoropter contains multiple lenses that can be adjusted to fine-tune your vision, helping to achieve the clearest and most comfortable correction possible.

Presbyopia Presbyopia – An age-related condition where the eye’s lens loses its flexibility, making it difficult to focus on close objects. Typically starting in your 40s, presbyopia is a natural part of aging and is commonly corrected with reading glasses, bifocals, or varifocal lenses.

Polarised lenses Polarised lenses – Sunglass lenses that filter out horizontal light waves, reducing glare from reflective surfaces like water, snow and roads. Polarised lenses improve visual comfort, reduce eye strain and enhance contrast, making them ideal for outdoor activities such as driving, fishing and skiing.

Photochromic lenses Photochromic lenses – Lenses that automatically darken when exposed to sunlight and return to clear when indoors. This technology provides convenience by eliminating the need to switch between prescription glasses and sunglasses. Photochromic lenses are available in a variety of lens materials and can also offer UV protection.