If you've just left the optometrist with a small white card covered in abbreviations — SPH, CYL, AXIS, BC, DIA, ADD — and you're trying to order contact lenses online, this guide explains everything in plain language. By the end, you'll know exactly which lens to buy and what to send to WhatsApp when ordering.
What Your Prescription Card Looks Like
Most Pakistani optometrist prescription cards show values like this:
| Eye | SPH | CYL | AXIS | BC | DIA |
|---|---|---|---|---|---|
| OD (Right) | -2.50 | -0.75 | 180 | 8.6 | 14.5 |
| OS (Left) | -2.25 | -1.00 | 175 | 8.6 | 14.5 |
Don't panic. Each value has a specific meaning and once you understand them, ordering lenses online is straightforward.
OD vs OS — Which Eye Is Which?
- OD (Oculus Dexter) = your right eye
- OS (Oculus Sinister) = your left eye
- Sometimes written as just "R" and "L" or "Right" and "Left"
Important: your two eyes often have different prescriptions. Always order separate lens powers for each eye.
SPH (Sphere) — The Main Power
SPH is your main vision correction power. This is what most people think of as "their prescription number".
- Negative SPH (-) = myopia (nearsightedness). You can't see far objects clearly. Most Pakistani buyers have negative SPH.
- Positive SPH (+) = hyperopia (farsightedness). You can't see near objects clearly.
- Zero SPH (0.00 or plano) = no main power needed (you may still need astigmatism correction)
Example readings:
- -1.00 = mild myopia
- -2.50 to -4.00 = moderate myopia (most common in Pakistan)
- -5.00 to -8.00 = high myopia
- -9.00 and above = very high myopia (needs special lens sourcing)
Contact lens powers come in 0.25 increments: -0.50, -0.75, -1.00, -1.25, and so on.
CYL (Cylinder) — Astigmatism Power
CYL measures astigmatism — an irregular cornea shape that causes blurry vision at all distances.
If your CYL is 0.00 or blank: You have spherical vision only and can use regular contact lenses (standard Acuvue, Biomedics, Bella, Dahab, etc.)
If your CYL has any value (like -0.75, -1.25, -2.00): You have astigmatism and need toric contact lenses, not regular spherical lenses.
See our complete toric lens guide for astigmatism-specific options.
AXIS — Astigmatism Direction
AXIS tells the contact lens manufacturer the direction of your astigmatism, measured in degrees from 1° to 180°.
Only matters if you have CYL. If CYL is zero, AXIS doesn't apply.
Common AXIS values: 90°, 180°, 5°, 175°. Your AXIS doesn't determine how strong your astigmatism is — only its orientation. A small change in AXIS (e.g., 175° vs 180°) is usually clinically equivalent.
BC (Base Curve) — Lens Fit
BC is the curvature of the lens, measured in millimeters. It must match your cornea shape for the lens to sit correctly.
- Most contact lenses are 8.6mm base curve (fits ~85% of people)
- Some are 8.4mm (smaller, for flatter corneas)
- Some are 8.7mm (larger, for steeper corneas)
If your prescription card doesn't mention BC, assume 8.6mm — that's the standard for most popular contact lens brands.
DIA (Diameter) — Lens Size
DIA is the lens diameter, measured in millimeters. Common values:
- 14.0mm — smaller lens (less common)
- 14.2mm — standard for most colored lenses (Bella, Dahab)
- 14.5mm — standard for transparent lenses (Acuvue, Biomedics)
Like BC, if not specified, the lens brand default usually works fine.
ADD — Reading Addition (Multifocal Only)
ADD is only relevant if you need multifocal contact lenses (typically for buyers over 40 with presbyopia). It represents the extra reading power added.
If your prescription doesn't show ADD, you don't need multifocal lenses — standard distance-correction lenses will work.
Glasses Prescription vs Contact Lens Prescription
Your glasses prescription is NOT identical to your contact lens prescription. Glasses sit ~12mm in front of your eye; contact lenses sit directly on the cornea. The difference matters at higher powers.
For SPH up to -4.00: Glasses and contact lens prescriptions are essentially the same.
For SPH above -4.00: Contact lens prescriptions are slightly weaker than glasses. For example, glasses prescription -6.00 might be contact lens prescription -5.50 or -5.75.
Always ask your optometrist for a specific contact lens prescription — don't just buy contact lenses using your glasses power.
A Complete Worked Example
Let's read this prescription card:
| Eye | SPH | CYL | AXIS | BC | DIA |
|---|---|---|---|---|---|
| OD | -3.25 | -1.25 | 180 | 8.6 | 14.5 |
| OS | -3.50 | -0.75 | 10 | 8.6 | 14.5 |
What this means:
- Right eye: moderate myopia (-3.25) with mild-moderate astigmatism (-1.25 at 180°). Needs toric lens.
- Left eye: moderate myopia (-3.50) with mild astigmatism (-0.75 at 10°). Needs toric lens.
- Both eyes: standard 8.6mm base curve, 14.5mm diameter — fits most major brands.
What to order: Biomedics Toric for both eyes, each with its specific SPH + CYL + AXIS values.
Common Prescription Scenarios
Scenario 1: Simple Myopia (No Astigmatism)
OD: -2.00 SPH / 0.00 CYL
OS: -2.25 SPH / 0.00 CYL
Order: Any standard transparent or colored lens. Affordable options: Biomedics 55, Acuvue 2, Bella Elite (if colored).
Scenario 2: Myopia + Astigmatism
OD: -2.00 SPH / -1.00 CYL / 180 AXIS
OS: -2.50 SPH / -1.25 CYL / 170 AXIS
Order: Toric lenses. Choose Biomedics Toric for both eyes.
Scenario 3: Very High Myopia (Above -8.00)
OD: -9.50 SPH / 0.00 CYL
OS: -10.00 SPH / 0.00 CYL
Order: Standard lens range stops at -8.00 to -10.00 SPH. WhatsApp +92 321 9455233 — we source higher powers through Dahab, Glimpse, and special order Acuvue High Power.
Scenario 4: Different Powers Each Eye
OD: -1.50 SPH
OS: -3.50 SPH
Order: Two different lens powers in the same box. Most monthly disposable boxes contain 6 lenses — order two boxes with different powers (or buy 3 pairs of right-eye power + 3 pairs of left-eye power).
Scenario 5: Plano (No Power) for Cosmetic Colored Lenses
OD: 0.00 (plano)
OS: 0.00 (plano)
Order: Any colored lens in plano. All Bella, Dahab, Freshlook colored lenses available in plano for cosmetic use.
How to Send Your Prescription via WhatsApp
- Take a clear photo of your prescription card in good lighting
- Make sure all values are visible — SPH, CYL, AXIS, BC, DIA per eye
- WhatsApp the photo to +92 321 9455233
- Tell us the brand/shade you want
- We verify availability for your specific power combination
- If your exact power isn't stocked, we'll suggest closest match or special order
Pro tip: If your prescription is recent (within 1 year), the optometrist will usually give you a separate slip specifically marked "contact lens prescription". If your prescription is older or unclear, ask for an updated one.
When to Get a New Prescription
Update your contact lens prescription:
- Every 1-2 years as routine maintenance
- Immediately if vision feels blurry with your current prescription
- After significant eye changes (pregnancy, major weight changes, age 40+)
- Before switching lens type (e.g., monthly to daily disposable, or spherical to toric)
Where to Buy Lenses Once You Know Your Prescription
Browse our eyesight lens range (31 prescription-eligible products), toric lens range for astigmatism, or all transparent prescription lenses. For prescription verification, WhatsApp +92 321 9455233.