Contact Lens Prescription Explained: How to Read Contact Lens Prescription

Every contact lens prescription may look different, but all include the same core information. Once you understand the basic parameters, reading a contact lens prescription is straightforward. This visual guide uses 15 real, anonymized examples to cover everything from simple myopia to complex multifocal toric lenses, helping both new and experienced wearers accurately understand and interpret their prescriptions.

How to Use This Visual Guide

Learning how to read contact lens prescription information starts with identifying your prescription type. This quick assessment helps you find the most relevant examples.

Find Your Prescription Type

Take this quick 3-question assessment:

Question 1: Do you see "CYL" and "Axis" on your prescription?

• No → You have spherical lenses (Examples 1-4)

• Yes → You have toric/astigmatism lenses (Examples 5-10)

Question 2: Do you see "ADD" or "D/N" markings?

• No → You have single vision lenses (Examples 1-10)

• Yes → You have multifocal or monovision lenses (Examples 11-13)

Question 3: Is your SPH (power) over ±6.00?

• No → You have a standard prescription (Examples 1-12)

• Yes → You have a high/specialty prescription (Examples 14-15)

Result: Based on your answers, start with the example that matches your situation.

>>> See more: How to Select Your Contact Lens Material Based on Prescription?

Understanding the Color-Coded System

Throughout this guide showing how to read a contact lens prescription, parameters are color-coded:

• 🟦 Blue = SPH/Power (vision correction strength)

• 🟩 Green = BC (Base Curve - how the lens fits your eye)

• 🟨 Yellow = DIA (Diameter - lens size)

• 🟥 Red = CYL/Axis (astigmatism correction)

• 🟪 Purple = ADD (reading addition power)

• ⚫ Black = Brand/lens type

This color system makes understanding your contact lens prescription explained simpler by helping you identify each parameter at a glance.

Understanding Basic Parameters First

Before reviewing contact lens prescription examples, it is important to understand what each parameter means when learning how to read a prescription.

>>> See more: How to Get a Contact Lens Prescription: Step-by-Step Process Explained

Section 1: Simple Spherical Prescriptions (No Astigmatism)

Example 1: Mild Myopia - The Most Common Type

        SPH     BC    DIA   Brand

OD:     -1.75   8.6   14.2  Dailies AquaComfort Plus

OS:     -1.50   8.6   14.2  Dailies AquaComfort Plus

🟦 SPH -1.75/-1.50: Mild short-sightedness. Close objects clear, distant objects slightly blurry. Right eye slightly stronger than left (normal 0.25 difference).

🟩 BC 8.6: Standard base curve for daily lenses, indicating average corneal curvature.

🟨 DIA 14.2: Standard diameter providing comfortable coverage.

⚫ Brand: Daily disposables. Cannot substitute without checking parameters match.

Typical wearer: Ages 18-45, slight distance blur. Cost: £15-25/month.

Example 2: Moderate Myopia

        SPH     BC    DIA   

OD:     -4.50   8.4   14.0  

OS:     -3.75   8.4   14.0  

Brand: Acuvue Oasys 1-Day

🟦 SPH -4.50/-3.75: Moderate short-sightedness. Very blurry distance without correction. 0.75 difference between eyes is normal.

🟩 BC 8.4: Steeper curve than Example 1. Cannot swap for 8.6 BC lenses.

🟨 DIA 14.0: Brand-specific sizing, smaller than Example 1.

Key point: May need separate boxes for each eye due to different powers.

>>> See more: Can You Buy Non Prescription Contacts?

Example 3: High Myopia

        SPH     BC    DIA   

OD:     -8.50   8.7   14.5  

OS:     -9.00   8.7   14.5  

Brand: Biofinity (Monthly)

🟦 SPH -8.50/-9.00: Severe myopia. Only see clearly within inches without correction. Limited brand availability, more expensive.

Special considerations: Limited to monthly lenses. Fewer options. May require special order. Cost: £30-45/month.

Example 4: Hyperopia (Long-Sightedness)

        SPH     BC    DIA   

OD:     +3.25   8.6   14.2  

OS:     +3.50   8.6   14.2  

Brand: Biotrue ONEday

🟦 SPH +3.25/+3.50: PLUS (+) values indicate long-sightedness. Difficulty seeing close objects. Less common than myopia in contact lenses.

Key difference: Positive values, lens thicker in center, fewer brand options.

Section 2: Toric Lenses (With Astigmatism)

When learning how to read contact lens prescription details, if you see CYL and Axis, you have astigmatism. These "toric" lenses must be positioned correctly. 

Example 5: Low Astigmatism

        SPH    CYL    Axis   BC    DIA   

OD:     -2.50  -0.75   180   8.6   14.5  

OS:     -2.25  -1.00   175   8.6   14.5  

Brand: Acuvue Oasys for Astigmatism

🟦 SPH -2.50/-2.25: Mild-moderate myopia.

🟥 CYL -0.75/-1.00: Low astigmatism causing slight blurring. Always negative values, remember this indicates corneal irregularity.

🟥 Axis 180/175: Critical must be exact. 180° = horizontal astigmatism (most common). Being off by 10° causes blur. Toric lenses must rotate to this position.

🟨 DIA 14.5: Larger diameter (vs 14.2) helps toric stability.

Common issues: Lens rotation (vision fluctuates), need toric-specific brands, slightly more expensive.

Example 6: Moderate Astigmatism - Different Axes

        SPH    CYL    Axis   BC    DIA   

OD:     -3.75  -1.75    90   8.4   14.5  

OS:     -4.00  -1.50    15   8.4   14.5  

Brand: Biofinity Toric

🟥 CYL -1.75/-1.50: Moderate astigmatism, more noticeable blur.

🟥 Axis 90/15: Very different axes—this is normal! Right: 90° = vertical. Left: 15° = near-vertical oblique. This is an important aspect of contact lens prescription explained for toric wearers.

Critical: Cannot swap lenses between eyes. Must order specifically for each eye.

>>> See more: Types of Contact Lenses: A Complete Guide to Finding Your Perfect Fit

Example 7: Astigmatism Only (No Myopia)

        SPH    CYL    Axis   BC    DIA   

OD:      0.00  -1.25    85   8.6   14.2  

OS:      0.00  -1.50    95   8.6   14.2  

Brand: Dailies AquaComfort Plus Toric

🟦 SPH 0.00 (Plano): No near/far-sightedness. Only astigmatism needs correction. 

Who has this: People with perfect spherical power but corneal irregularity. Often athletes choosing contacts over glasses.

Section 3: Multifocal & Monovision (Age 40+)

When learning how to read contact lens prescription for presbyopia, you'll see ADD on your prescription or D/N markings for monovision. This section of contact lens prescription explained covers age-related vision changes.

Example 11: Multifocal - Low ADD (Early Presbyopia)

        SPH    ADD    BC    DIA   

OD:     -2.00  +1.00  8.6   14.2  

OS:     -2.25  +1.00  8.6   14.2  

Brand: Dailies AquaComfort Plus Multifocal

🟦 SPH -2.00/-2.25: Mild myopia for distance correction.

🟪 ADD +1.00: Low addition indicating early presbyopia. Added power for reading and close work. Typically ages 42-48. Same ADD for both eyes is common.

How multifocal lenses work: They provide simultaneous vision zones (distance and near at once). Your brain learns to select the appropriate zone. Adaptation period typically takes 1-2 weeks.

What this means: You can read phone screens or menus without reading glasses whilst maintaining distance vision. There's some compromise in both (not as sharp as single vision).

Alternative: You could use single vision contacts plus reading glasses instead.

Example 12: Multifocal - High ADD (Advanced Presbyopia)

        SPH    ADD    BC    DIA   

OD:     -1.00  +2.25  8.6   14.3  

OS:     -1.25  +2.25  8.6   14.3  

Brand: Acuvue Oasys Multifocal (High)

🟪 ADD +2.25: High addition indicating advanced presbyopia. Typically age 55+. Significant difficulty reading without help. Maximum available in most brands is +2.50.

Brand simplification: Instead of exact ADD values, some brands use Low/Med/High designations. This prescription would be labeled "High" (Low = +0.75 to +1.25, Med = +1.50 to +1.75, High = +2.00 to +2.50).

Reality check: Multifocal compromise increases with higher ADD. Some people prefer monovision (see Example 13). You may still need reading glasses for very fine print.

Example 13: Monovision - Alternative to Multifocal

        SPH    BC    DIA   Designation

OD:     -2.50  8.6   14.2  D (Distance)

OS:     -0.50  8.6   14.2  N (Near)

Brand: Acuvue Moist

Right eye -2.50 [D]: Corrected for distance vision. "D" indicates this is your dominant eye, used for driving, TV, and distance activities.

Left eye -0.50 [N]: Deliberately under-corrected (blurry for distance). "N" indicates this is your non-dominant eye, used for reading, phone, and close work.

How monovision works: Your brain suppresses the image from the inappropriate eye for each task. Takes 2-4 weeks adaptation. Not everyone adapts successfully—trial period essential.

Advantages: Sharper distance and near vision (no compromise like multifocal). Often less expensive.

Disadvantages: Reduced depth perception. Some situations need glasses (night driving). Not suitable for everyone.

Section 4: Complex & Specialty Prescriptions

Example 14: High Myopia + High Astigmatism

        SPH    CYL    Axis   BC    DIA   

OD:     -9.50  -3.00   175   8.8   14.5  

OS:    -10.00  -2.75     5   8.8   14.5  

Brand: Custom Toric (Special order - 6-8 week delivery)

🟦 SPH -9.50/-10.00: Severe myopia. 🟥 CYL -3.00/-2.75: High astigmatism.

Why this is complex: Very limited brand availability. Often requires custom manufacturing. Significantly more expensive (£80-120/month). Longer delivery times. 

Alternative options: RGP/hard lenses (better optics), scleral lenses (larger, more stable), or refractive surgery.

Example 15: Multifocal Toric (Most Complex)

        SPH    CYL   Axis  ADD   BC    DIA   

OD:     -3.50  -1.25  180  +1.50  8.6   14.5  

OS:     -4.00  -1.50   10  +1.50  8.6   14.5  

Brand: Biofinity Toric Multifocal

This contact lens prescription explained has everything: Distance correction (myopia), astigmatism correction, AND reading correction (presbyopia) all in one lens.

Why most complex: Corrects three issues simultaneously. Requires precise positioning. Limited brand availability. Most expensive soft contact option (£45-70/month). Longest adaptation period (2-4 weeks).

Realistic expectations: 80-90% satisfied. 10-20% need glasses for some tasks. Computer work may need adjustment.

Alternatives: Toric single vision plus reading glasses, monovision toric, or RGP multifocal.

>>> See more: Understanding Base Curve and Diameter in Contact Lenses: A Complete Guide

Comparing Prescription Formats Across Brands

When learning how to read a contact lens prescription, it is important to understand that the same prescription may appear in different formats depending on the optician. Below are four common layouts showing the same contact lens prescription.

Specsavers Format:

Name: [Redacted]          Date: 10/01/2025

Right Eye: -3.00 | 8.6 | 14.2 | Acuvue Moist

Left Eye:  -2.75 | 8.6 | 14.2 | Acuvue Moist

Expiry: 10/01/2027

Boots Opticians Format:

[Redacted] - Contact Lens Specification

         Power  BC   DIA  Brand

R:      -3.00  8.6  14.2  Acuvue Moist  

L:      -2.75  8.6  14.2  Acuvue Moist

Valid until: 10/01/2027

Vision Express Format:

Contact Lens Rx

OD: SPH -3.00, BC 8.6, DIA 14.2

OS: SPH -2.75, BC 8.6, DIA 14.2

Brand: Acuvue Moist (Daily)

Expires: 10/01/2027

Same prescription, different formats all equally valid when you know how to read a contact lens prescription.

How to translate between formats (essential for how to read contact lens prescription from any optician):

• OD = Right = R = RE (all mean right eye)

• OS = Left = L = LE (all mean left eye)

• SPH = Power = PWR (all mean the same)

• All measurements use the same units regardless of format

Prescription Validity and Legal Requirements (UK)

Understanding your contact lens prescription explained includes knowing UK legal requirements.

What Makes a Valid Prescription?

Your prescription must include:

• Patient full name

• Date of examination

• Prescription expiry date

• All parameters (minimum: SPH, BC, DIA)

• Brand specification

• Optometrist/practice details

• Signature or practice stamp

Typical validity: 1-2 years from examination date.

Your Legal Rights (UK)

• You're entitled to a copy of your prescription

• Your optician cannot refuse to provide it

• You can order from any retailer

• You have no obligation to buy from the prescribing optician

Understanding a contact lens prescription is simple once you know the key parameters. The main values include SPH (power), BC (base curve), and DIA (diameter), with additional details such as CYL/Axis for astigmatism or ADD for multifocal lenses. These apply to spherical, toric, multifocal, and specialty lenses. Always follow your exact prescription and never substitute values. If anything is unclear, consult your optician for confirmation.