Contact lenses explained: daily, bi-weekly or monthly, clear or colored
The short answer
Daily lenses are worn once and thrown away, so they need no cleaning and suit occasional wear and sensitive eyes. Bi-weekly lenses are replaced 14 days after opening and monthly lenses after 30 days; both are cleaned and stored in solution every night and cost less per day. Clear lenses only correct vision, while colored lenses change your eye colour and come with or without power. Order with a contact lens prescription (power, base curve and diameter), not your glasses prescription.
Daily, bi-weekly and monthly: what's the difference?
The difference is the replacement schedule: how long you can use a lens after opening it. The manufacturer sets it for each lens, and it's printed on the box.
- Daily (daily disposable): put in a fresh pair each morning and throw it away at night. No solution, no case, no cleaning.
- Bi-weekly: replace 14 days after opening. Take the lenses out every night, then clean and store them in fresh solution.
- Monthly: replace 30 days after opening, with the same nightly cleaning routine.
The count starts when you open the blister pack, not with the days you actually wore the lenses. A monthly lens you only wear at weekends still needs replacing 30 days after you opened it.
Which replacement schedule is right for you?
- Choose daily lenses if you wear contacts now and then (weekends, events, sport or travel), if you have allergies or sensitive eyes, or if you don't want a cleaning routine. They cost more per day of wear, but you don't buy solution.
- Choose bi-weekly or monthly lenses if you wear contacts most days and are happy to clean them every night. They cost less per day, plus the cost of solution and a new lens case every few months.
Whatever you choose, stick to the schedule on the box. Wearing lenses past their replacement date, or sleeping in lenses that aren't approved for overnight wear, is a common cause of red, irritated eyes and infections. If your eye care professional recommended a specific lens or schedule, follow their advice.
Clear vs colored contact lenses
Clear lenses correct your vision without changing how your eyes look. Many have a faint blue handling tint so you can see the lens in its case. Colored lenses have a printed pattern over the iris that enhances or changes your eye colour, from natural honey and hazel shades to grey, green and blue.
Colored lenses come in two kinds: with power, for people who need vision correction, and without power (0.00, also called plano), worn just for the look. Both are medical devices that sit on your eye, so the same rules apply: buy from a trusted seller, follow the replacement schedule, never share lenses, and take them out if your eyes become red or painful. Colored lenses usually come in a smaller range of powers than clear ones, so check that your power is available before you pick a colour.
How to read a contact lens prescription
A contact lens prescription lists each eye separately: OD or R for the right eye, OS or L for the left. You'll usually see:
- PWR or SPH (power): the strength in dioptres, with a minus sign for short-sightedness and a plus sign for long-sightedness, for example −2.25.
- BC (base curve): the curve of the back of the lens in millimetres, for example 8.4 or 8.6. It affects how the lens sits on your eye.
- DIA (diameter): the width of the lens in millimetres, usually between 13.8 and 14.5.
- CYL and AXIS: only for toric lenses, which correct astigmatism.
- ADD: only for multifocal lenses, which add reading power.
The prescription may also name a specific brand, because base curve and diameter differ from lens to lens. When you order on Qurrah, you choose the power for each eye separately from the values available for that lens.
Your glasses prescription is not a contact lens prescription
Glasses sit about 12 mm in front of your eyes, while contact lenses sit directly on them, so the power you need can be different, especially for prescriptions stronger than about ±4.00. A glasses prescription also has no base curve or diameter.
If you only have a glasses prescription, or you're wearing contacts for the first time, book a contact lens fitting with an optometrist or ophthalmologist. They'll check that the lens fits your eye and that your eyes are healthy enough for contacts, and teach you how to put lenses in and take them out safely.
Buying contact lenses online in Egypt
At Qurrah you can shop clear and colored contact lenses from brands such as ACUVUE, Dailies, Bella and Avaira, and filter by replacement schedule. Compare pack sizes, choose the power for each eye and pay cash on delivery. Standard delivery is free in Cairo and Giza, and unopened boxes can be returned within 14 days of delivery.
Frequently asked questions
Are daily contact lenses better than monthly ones?
Not better, just different. Dailies are the most convenient and hygienic option because you start with a fresh lens every day, which suits occasional wearers and sensitive eyes. Monthlies cost less per day for people who wear lenses daily and don't mind cleaning them each night.
Can I sleep in my contact lenses?
Only if the lens is approved for overnight wear and your eye care professional says it's suitable for you. Most daily, bi-weekly and monthly lenses are made for daytime wear and should come out before you sleep.
Do I need a prescription for colored lenses without power?
They still have to fit your eye: even 0.00 colored lenses have a base curve and diameter. If you've never worn contact lenses, have an eye exam and a fitting first.
Can I order contact lenses with my glasses prescription?
Not directly. Contact lens power can differ from glasses power, and a glasses prescription has no base curve or diameter. Ask your optometrist for a contact lens prescription.
How long does a box of contact lenses last?
It depends on the replacement schedule and the number of lenses in the box. A 30-lens box of dailies lasts 15 days for both eyes, and a 6-lens box of monthlies lasts 3 months for both eyes.