SPH (sphere) describes the main lens power for myopia or hyperopia. CYL (cylinder) describes astigmatism correction, and Axis gives its orientation in degrees. Use the values exactly as written on your current prescription; ask your optometrist if any entry is unclear.

PD is the distance between the centres of your pupils, used to position the optical centres of spectacle lenses. Accurate measurement matters, particularly for stronger prescriptions. Use a reliable measurement from an eye-care professional rather than guessing.

No. Contact lenses sit directly on the eye and require a contact-lens-specific prescription and fitting. Parameters may include power, base curve (BC) and diameter (DIA), along with the exact lens type. Do not convert spectacle power yourself.

Follow the validity period and review advice given by your eye-care professional. If your vision has changed, you have symptoms, or the prescription is old or unclear, arrange an eye examination before ordering.

Single-vision lenses provide one main correction zone. Progressive lenses combine distance, intermediate and near zones in one lens, with a gradual change in power. Progressive fitting requires accurate measurements and some people need an adaptation period.

No. Lens index affects how thin a lens can be for a given prescription, but the best choice depends on prescription strength, frame size, material, optical quality and budget. Ask an optometrist or qualified optical professional to recommend a suitable option.

Not necessarily. Evidence for blue-light filtering spectacles preventing digital eye strain is limited. Screen comfort often improves with regular breaks, blinking, suitable lighting, screen distance and an up-to-date prescription. Seek clinical advice for persistent symptoms.

No. Lens compatibility depends on frame construction, lens material, prescription, thickness limits and fitting measurements. Confirm compatibility before placing a prescription order.

Do not sleep or swim in contact lenses unless a qualified eye-care professional has specifically advised a suitable approved regimen. Water exposure increases the risk of serious eye infection. Follow the lens manufacturer’s wear and care instructions.

Remove your contact lenses and seek prompt assessment from an eye-care professional, especially if you have pain, light sensitivity, discharge or blurred vision. Do not continue wearing lenses while symptoms persist.