If you’re preparing for cataract surgery or refractive lens exchange (RLE), one of the biggest decisions you’ll make is choosing the right type of intraocular lens (IOL). Two of the most common options are monofocal lenses and EDOF (Extended-Depth-of-Focus) lenses. On the surface, the choice might seem simple monofocals offer crisp distance vision, while EDOF lenses give you more range. But in reality, surgeons consider far more than just those two points before making a recommendation.
I want to help you understand how surgeons really make this decision, because the right IOL depends on you the way you use your eyes, your daily routines, your night-driving habits, your reading needs, your sensitivity to glare and even your personality. By the end of this article, you’ll have a much clearer picture of how ophthalmologists tailor lens recommendations, and you’ll feel better equipped to choose the IOL that offers the best long-term vision for your lifestyle.
Understanding the Two Main Lens Types
Before diving into how surgeons choose between monofocal and EDOF lenses, it helps to understand what each lens offers.
What Is a Monofocal IOL?
A monofocal lens has a single focal point usually set for distance vision.
What monofocals offer:
- Sharp, high-contrast distance vision
- Excellent clarity in low-light situations
- Minimal glare and halos
- Best performance for night driving
- Most predictable visual quality
Most people who choose monofocal lenses will still need reading glasses for close-up tasks.
What Is an EDOF IOL?
EDOF lenses create a stretched focal range, giving you clearer vision from distance to intermediate, with some functional near vision.
Examples include:
- Alcon Vivity (non-diffractive)
- Symfony IOL (diffractive)
What EDOF lenses offer:
- Good distance vision
- Excellent intermediate vision
- Functional near vision for many tasks
- Fewer visual disturbances than multifocals
- A balanced compromise between clarity and freedom from glasses
These lenses are ideal for people who want more independence from glasses without the stronger visual side effects of trifocal lenses.
How Surgeons Decide: The Factors That Really Matter
Choosing an IOL isn’t just a clinical decision it’s a lifestyle decision. Surgeons match lens technology to your visual needs, your tolerance, your work habits and your daily activities.
Here’s what influences their recommendations.
1. Your Daily Visual Priorities
Surgeons want to understand how you use your eyes most of the day.
If you spend a lot of time driving:
Monofocal lenses may be preferred because they give the sharpest night-time clarity and least glare.
If you spend hours at the computer:
EDOF lenses are ideal because intermediate vision is one of their biggest strengths.
If you read small print often:
You may still need reading glasses with EDOF lenses, but some people manage well without for larger text.
2. Your Night Driving Habits
Night driving is one of the most important factors in lens selection.
Monofocals:
- Best lens for low-light clarity
- Lowest risk of glare and halos
- Perfect for frequent night drivers
EDOF lenses:
- Non-diffractive EDOF (e.g., Vivity) perform well
- Diffractive EDOF lenses may show some halos
If you rely heavily on driving at night, your surgeon may recommend monofocals or non-diffractive EDOF lenses for safer, sharper night vision.
3. Your Sensitivity to Glare and Halos
Some people are naturally more sensitive to light scatter than others.
Your surgeon will ask:
- Do headlights bother you now?
- Do you struggle with reflections at night?
- Does bright sunlight feel uncomfortable?
If you’re sensitive:
Monofocals are the safest option.
Non-diffractive EDOF lenses may also work.
If you’re not sensitive:
Diffractive EDOF lenses might suit you well.
4. Your Desire for Glasses Independence
This is a key driver in choosing an IOL.
Monofocal users:
- Usually wear reading glasses
- May need intermediate glasses for screens
EDOF users:
- Often don’t need glasses for computer tasks
- Sometimes need reading glasses for very close work
- Enjoy a balanced range of vision
Your preference regarding glasses heavily shapes the final recommendation.
5. Pupil Size and Eye Anatomy
This is something we covered in depth in another article, but to summarise:
Monofocals:
Reliable for all pupil sizes.
Diffractive EDOF lenses:
Better for medium pupils.
Non-diffractive EDOF lenses:
Excellent for larger pupils.
If your anatomy suggests you may struggle with visual artefacts from diffractive rings, your surgeon may guide you away from that technology.
6. Corneal Quality and Aberrations
Your corneal surface shape is critical.
If you have:
- Irregular astigmatism
- Higher-order aberrations
- Previous LASIK/PRK/SMILE
- Dry eye disease
Your surgeon may lean toward monofocals or non-diffractive EDOF lenses for the most reliable results.
Diffractive EDOF lenses and multifocals require a very healthy, symmetrical cornea to perform optimally.
7. Your Occupation
Your job influences your ideal IOL type.
Monofocal lenses suit:
- Frequent drivers
- Pilots
- Night workers
- People who prefer visual sharpness over range
EDOF lenses suit:
- Office workers
- Freelancers working on laptops
- Teachers, consultants and creatives
- People who move between devices and physical work
- Anyone who values versatility
Your surgeon tries to match your lens to your typical workday.
8. Your Hobbies and Lifestyle
Surgeons also consider what you enjoy doing in your free time.
Monofocal users:
- Golfers
- Cyclists
- People who enjoy outdoor sports
These activities rely heavily on clear distance vision.
EDOF users:
- Gardeners
- Photographers
- Travellers
- Readers who prefer a wider range of vision
- People using tablets or phones often
Your lens choice should support the activities you love.
9. Your Personality and Visual Tolerance
Believe it or not, personality plays a huge role.
If you prefer sharpness and predictability:
You’ll adapt better to monofocals.
If you’re easy-going about small visual changes:
You may adapt quickly to EDOF lenses.
If you’re visually perfectionist:
EDOF may frustrate you unless you choose a non-diffractive model.
Your surgeon will often try to understand your expectations before recommending anything.
10. One Eye or Both?
Sometimes, mixing lens types is the perfect solution.
Blended vision options include:
- One monofocal (distance) + one EDOF (range)
- One EDOF set slightly myopic for better near vision
Surgeons use blended vision to optimise your full visual range.
Comparing Monofocal and EDOF: What Surgeons Consider Side by Side
Distance Vision: Both Monofocal and EDOF lenses provide excellent distance vision.
Intermediate Vision: Monofocal lenses have limited performance, while EDOF lenses provide strong intermediate vision.
Near Vision: Monofocal users typically need glasses for near tasks, whereas EDOF lenses allow functional near vision.
Night Driving: Monofocal lenses are generally the best choice for night driving. EDOF performance depends on the lens type.
Glare and Halos: Monofocal lenses have minimal glare or halos. EDOF lenses vary: low for non-diffractive types, moderate for diffractive types.
Range of Focus: Monofocal lenses offer a narrow range of focus, while EDOF lenses provide an extended range.
Corneal Requirements: Monofocal lenses are more forgiving, whereas diffractive EDOF lenses need higher corneal quality.
Suitability for Large Pupils: Monofocal lenses perform very well; non-diffractive EDOF lenses are excellent.
Suitability for Perfectionists: Monofocal lenses are ideal for perfectionists; EDOF suitability depends on individual tolerance.
Case Examples: How Surgeons Decide in Real Life
Case 1: Heavy Night Driver with High Sensitivity
- Drives long distances
- Sensitive to glare
- Wants predictable clarity
Recommendation:
Monofocal
or
Non-diffractive EDOF (if they want some range)
Case 2: Office Worker Using Screens 8 Hours a Day
- Needs strong intermediate vision
- Doesn’t mind occasional glasses
- Minimal night driving
Recommendation:
EDOF lens (appropriate model depending on anatomy)
Case 3: Retired, Active, Outdoor Lifestyle
- Loves golf
- Enjoys walking and cycling
- Doesn’t want glare
Recommendation:
Monofocal lenses for crisp distance
Case 4: Traveller Who Wants Freedom from Glasses
- Uses smartphone and camera
- Moves between different environments
- Wants fewer visual disturbances
Recommendation:
Non-diffractive EDOF
or
Blended vision
Why EDOF Lenses Are Becoming More Popular
More people today want a balanced solution:
- Less glare than multifocals
- Better range than monofocals
- More freedom in daily tasks
- Comfortable intermediate vision
For many, EDOF lenses are the “happy medium” between clarity and convenience.
Why Monofocals Remain the Gold Standard
Despite the rise of advanced lenses, monofocals remain the most widely implanted IOL because:
- They offer the sharpest distance vision
- They have the lowest side-effect profile
- They work for all pupil sizes
- They suit patients with corneal irregularities
- They offer exceptional night visibility
For people who prioritise crisp, reliable visual quality, monofocals remain unmatched.
Frequently Asked Questions:
1. What is the main difference between monofocal and EDOF lenses?
The primary difference lies in the range of focus each lens provides. Monofocal lenses are designed with a single focal point, usually set for distance vision, offering crisp and predictable clarity for faraway objects. EDOF lenses, on the other hand, extend the focal range, providing clear vision from distance to intermediate and functional near vision, which allows users to handle daily tasks like computer work or tablet use more easily without constantly relying on glasses.
2. Will I still need glasses if I choose a monofocal lens?
Yes, most people who opt for monofocal lenses will still require reading glasses for close-up tasks. While these lenses deliver excellent distance vision and superior night clarity, they do not provide the extended focal range that some other lenses, such as EDOF, offer. For activities like reading fine print, sewing, or smartphone use, glasses remain necessary.
3. Can EDOF lenses completely eliminate the need for glasses?
EDOF lenses can significantly reduce the reliance on glasses, especially for intermediate and some near tasks, but they do not always eliminate the need entirely. While many patients can perform computer work, tablet use, and casual reading without glasses, very close reading or prolonged fine-detail work may still require occasional spectacles. The degree of independence varies depending on the specific lens type and individual visual needs.
4. Which lens is better for night driving?
Monofocal lenses generally provide the sharpest clarity for night driving due to their minimal susceptibility to glare and halos. EDOF lenses can perform well in low-light conditions, particularly non-diffractive designs, but diffractive EDOF lenses may produce mild halos or light scatter that can be noticeable in certain nighttime scenarios. Surgeons often consider how frequently a patient drives at night when recommending an IOL.
5. How does pupil size affect lens choice?
Pupil size is an important anatomical factor. Monofocal lenses perform reliably across all pupil sizes, making them a flexible option. Non-diffractive EDOF lenses are particularly well-suited for larger pupils, providing a consistent extended range of vision. Diffractive EDOF lenses tend to work best with medium-sized pupils, as larger pupils can sometimes increase the perception of visual artefacts such as halos or glare.
6. Are there differences in how these lenses handle glare and halos?
Yes, glare and halos are managed differently depending on the lens design. Monofocal lenses have minimal glare or halos, making them ideal for patients sensitive to light scatter or reflections. Non-diffractive EDOF lenses also tend to produce low visual disturbances, whereas diffractive EDOF lenses may generate moderate halos under certain lighting conditions. Surgeons evaluate a patient’s sensitivity to light when making a recommendation.
7. Does corneal quality matter for lens selection?
Corneal health plays a significant role in lens performance. Monofocal lenses are more forgiving for patients with irregular corneas, previous refractive surgery, or higher-order aberrations. Diffractive EDOF lenses require a very regular and healthy corneal surface to function optimally. Non-diffractive EDOF lenses can accommodate some corneal irregularities but still need a relatively smooth corneal shape to deliver consistent visual quality.
8. Can I have different lenses in each eye?
Yes, surgeons sometimes recommend a blended vision approach, where one eye receives a monofocal lens for crisp distance vision and the other an EDOF lens to extend range. This strategy allows patients to benefit from the strengths of both lenses, improving intermediate and near vision while maintaining excellent distance clarity. Blended vision is particularly useful for patients who want a balance of spectacle independence and reliable night driving performance.
9. Which lens is better for active lifestyles or outdoor sports?
For activities that rely heavily on clear distance vision, such as golf, cycling, or driving, monofocal lenses remain a strong choice. They provide the most predictable clarity and the least susceptibility to glare. EDOF lenses can suit outdoor enthusiasts who also value versatility in intermediate vision for tasks like photography, gardening, or navigating digital devices, but individual tolerance to visual artifacts and lighting conditions must be considered.
10. How do personality and visual expectations affect lens choice?
A patient’s attitude and tolerance for minor visual compromises are often critical. People who prioritize perfect sharpness and predictability tend to adapt better to monofocal lenses, enjoying the reassurance of consistent distance clarity. Those who are flexible and willing to accept slight variations in vision for more independence from glasses often do well with EDOF lenses. Surgeons take the time to understand a patient’s expectations, daily routines, and lifestyle priorities to ensure the lens choice aligns with both visual and personal preferences.
Final Thoughts: Choosing the Safest Path to Multifocal Vision After a Monofocal IOL
Upgrading your vision after receiving a monofocal IOL is far more achievable than most people realise. Whether you want clearer near vision, sharper intermediate focus for computer work, or a fuller range without relying on glasses, there are several safe and effective options to choose from. The right pathway depends on your capsule clarity, whether you’ve had YAG treatment, your corneal health, and the type of visual freedom you want in daily life.
Modern techniques from trifocal and EDOF IOL exchange to reversible piggyback lenses and precise laser-based blended vision allow your surgeon to match the solution to your unique anatomy and lifestyle. Each method has its strengths, and the goal is always the same: to give you greater independence with the lowest possible risk. If you’re thinking about IOL replacement surgery in London, feel free to contact us at the London Cataract Centre. Our team can guide you through your options and arrange a thorough assessment tailored to your eyes.
References:
1. Chao, C.-C. & Chang, C.-K. (2022) ‘Difference in Quality of Vision Outcome among Extended Depth of Focus, Bifocal, and Monofocal Intraocular Lens Implantation’, Healthcare, 10(6), p. 1000. https://www.mdpi.com/2227-9032/10/6/1000
2. Kim, D.Y. et al. (2025) ‘Comparative Outcomes of the Next-Generation Extended Depth-of-Focus Intraocular Lens and Enhanced Monofocal Intraocular Lens in Cataract Surgery’, Journal of Clinical Medicine, 14(14), p. 4967. https://www.mdpi.com/2077-0383/14/14/4967
3. Atypon / Real‑World IOL study (2020) ‘Extended Depth of Focus Versus Monofocal IOLs: Objective and Subjective Visual Outcomes’, Journal of Refractive Surgery, 36(4), pp. 214–222. https://pubmed.ncbi.nlm.nih.gov/32267951/
4. Liu, J.R. et al. (2025) ‘Outcomes of a non‑diffractive extended depth of focus lens versus a monofocal IOL: Long‑term patient‑reported and clinical outcomes’ https://pmc.ncbi.nlm.nih.gov/articles/PMC11672098/ 5. Vision and patient‑reported outcomes with nondiffractive EDOF or neutral aspheric monofocal intraocular lenses. https://pubmed.ncbi.nlm.nih.gov/36728998/