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Monofocal Cataract Surgery – Lens Replacement
Medically reviewed by: Prof. Dr. Levent Alimgil · Last updated: 7 September 2026
Monofocal intraocular lens
A monofocal IOL provides sharp vision at a single distance. It is the longest-established lens type in cataract surgery and the one with the most predictable optical performance. It is usually set for distance, with glasses used for reading and close work.
Who is it suited to?
- People who drive at night frequently and want to minimise glare and haloes
- Eyes with macular disease, advanced glaucoma or an irregular cornea, where multifocal designs are avoided
- Patients who do not mind wearing glasses for near work
- Anyone who prioritises contrast sensitivity
Strengths and limits
Contrast sensitivity is high and night-time glare is less likely than with multifocal designs. The trade-off is that glasses are needed outside the chosen focal distance. Monovision — setting one eye for distance and the other slightly for near — can be considered in selected patients, but requires adaptation and does not suit everyone.
Toric monofocal lenses
For eyes with significant corneal astigmatism, toric monofocal lenses are used. Correct axis alignment directly affects the result, so corneal topography and axis measurement are performed carefully before surgery.
Lens Replacement with Monofocal Lens
Monofocal Lenses are prosthetic lenses that are place inside the eye in Monofocal Cataract Surgery and allow you to see the distance clearly. As a result, this type of lenses corrects ametropia (nearsightedness) and allows you to see far and middle distances clearly without glasses.
In particular, patients using Monofocal lenses can only see the close objects with 2.5 diopter reading glasses. This type of lenses is preferred for Cataract patients over the age of 40-45.
How does vision loss occur in cataract disease?
Especially with the increase of Cataract grade, it is possible to experience age-related vision loss at all levels after the age of 60. If you are unsure whether this is due to a Cataract, you may still be eligible for lens replacement surgery. After all, this is an operation in which your natural lens can be replace with an artificial lens. In particular, it is necessary to make a very accurate and careful decision.
If wrong type of lens is use on unsuitable eyes, there will be permanent side effects. Permanent problems such as poor vision, flashing of light, glare at night and similar may occur. In particular, with Myopic (Nearsightedness) patients, if they don’t have Cataract problem, should be very careful if they want to have Multifocal or Trifocal lens replacement surgery. It is a medical fact that, with Hyperopia (Farsightedness) patients, Trifocal or Multifocal lens replacement could be more satisfactory with this treatment. Make sure that our eye surgeons will give you the most accurate information as a result of your examination.
Monofocal Cataract Surgery is relatively easy treatment.
Today, with the advancement of Phaco technology is use in Cataract surgery. Especially since our eye surgeons have wide experience and use new technologies, our patients can operate safely. Our highly experienced and expert eye surgeons will give you clear information to make the right decision. Lens replacement surgeries are very safe and a common surgical procedure performs in our clinics.
Lens selection is the most important issue in Monofocal Cataract Surgery
There are many lens manufacturers available for prosthetic lens selection. Especially our eye surgeons, the decision is made by researching the features of all lens manufacturers and choosing the most suitable one for the patient. The country in which the lens is manufactured is not a priority. The most important thing in lens selection is to determine the most suitable lens for your eye as a result of diagnosis. The most suitable lenses for our patients are offer with alternatives and we can provide for you from the any manufacturer.
Naturally, it may seem difficult for you to decide who to trust, but the most important thing is to take the time to make your decision and research your options thoroughly. We want you to be sure that you will make the right decision for the selection of the most suitable lens for your eyes with our experienced and expert surgeons. For this reason, lenses are not sell in our hospitals in order to offer transparent and clear costs to our patients. We ensure that the most suitable lenses are use for you.
Book for free expert consultation
If you are wondering if you can have Cataract Surgery? You can now make your Cataract consultation appointment from the Smart Laser Eye Center. If lens replacement is not suitable for you, our experts will try to offer you alternative solutions. To learn more about what our centers have to offer and to get answers to your questions, we ask you to reach out to our experts directly.
Useful Links:
Cataract Lens Replacement Surgeries
Phakic Intraocular ICL Lens Surgery.
Vitrectomy Surgery. Cataract Surgery Medical Description Wiki. Keratoconus Cross-Linking Surgery. Blepharoplasty Aesthetic Surgeries. Dry Eye Syndrome Treatments. Periodic Eye Examinations. Glaucoma Treatments.
Monofocal lens planning with RLES AI®
Two things decide the result with a monofocal lens: the correct lens power and which distance it is set for. In our centre these are additionally checked with RLES AI®, an artificial-intelligence assisted planning tool.
RLES AI® is a clinical decision support tool. It does not diagnose and does not decide on surgery. It checks the measurements in the same order in every case and shows the surgeon what is missing and what carries risk; the surgeon decides.
Which data are checked before surgery?
- Biometry: axial length, anterior chamber depth and corneal power (K1/K2/Kmax)
- Corneal map: magnitude and axis of astigmatism, screening for irregularity
- Macula and retina: OCT assessment; it directly affects which lens type is suitable
- Tear film: dry eye is the first thing that can make measurements unreliable
- Anterior chamber angle: a narrow angle is flagged separately for further assessment
- Pupil size and daily visual needs: including your occupation and night driving
How is lens power calculated?
The power of the implant is calculated from the measured values, and the choice of formula depends on the eye. In eyes that have had previous laser vision correction standard formulas can drift; these eyes need adjusted formulas, and records of the earlier procedure improve accuracy. RLES AI® checks this consistency and flags missing input; the surgeon completes the calculation on their own platform.
Toric and monovision decisions
If astigmatism is present, the toric model and its alignment axis are calculated separately; an off-axis lens gives back part of the correction. In a monovision plan, tolerance between the two eyes and depth perception are assessed as well. RLES AI® asks for each of these items.
RLES AI® does not make a diagnosis and does not decide on surgery. It flags risks, thresholds and missing data; the final decision and responsibility rest with the surgeon. More information: rlesai.com
Why you should avoid low-cost cataract surgery
A cheap cataract operation may look like a sensible choice at first. However, the items that bring the price down are usually the same ones: the quality of the measurement and imaging devices, the operating-room conditions, the type of intraocular lens implanted and the surgeon’s experience. Buying a cheap television costs you nothing; with your eyesight, the price can be permanent.
Therefore, look at what the fee covers rather than at the fee alone. Before surgery, we suggest you ask about four things:
- Measurement and imaging: Are biometry, corneal topography and macular OCT performed, and is the equipment current? Your lens power is calculated from these measurements.
- Surgeon and clinical team: Who will operate, and what is their experience in cataract and intraocular lens surgery?
- Operating room: Is the procedure carried out in a fully equipped, sterile hospital operating theatre?
- The lens: Which brand and type of lens will be implanted, and is the price difference for a toric or premium option given to you in writing beforehand?
In addition, we remind every patient of something simple: you have two eyes, and sight is the most delicate of the senses. Consequently, technology and medical quality are the last places to economise, and we do not compromise on either.
There are no hidden costs in our pricing. We set out in writing what the surgical fee includes, and we offer instalment options on suitable terms.
Frequent Ask Questions about Monofocal Cataract Surgery
Can a toric lens rotate out of position?
A toric lens is aligned to the measured axis. However, slight rotation can occur in the first days, and part of the astigmatic correction then returns. For this reason the axis is checked at your follow-up visits. If needed, the lens can be realigned in a short procedure; therefore early follow-up matters.
Does a monofocal lens last for life?
Yes. An intraocular lens is not absorbed by the body and does not degrade over time, so it does not need replacing. Moreover, the capsular bag that holds it is preserved, which keeps the lens stable in position for many years.
What is a YAG capsulotomy, and will I need one?
Months or years after surgery the thin membrane behind the lens can cloud over, which is called posterior capsule opacification. Vision then becomes hazy again. However, treatment is short and painless: a YAG laser opens the membrane in a few minutes. This is not a repeat of cataract surgery, and one treatment is usually enough.
Can the lens be set for near instead of distance?
Yes, the target distance is decided together with you. For example, a patient who reads a great deal may prefer a near target, in which case glasses are needed for distance. The choice therefore depends on your occupation and daily habits.
Does dry eye affect the result?
Yes, it affects both the measurements and the outcome. If the tear film is unstable, the readings used to calculate lens power can shift. For this reason dry eye is treated first, and the measurements are then repeated.
Are both eyes operated on the same day?
Usually a few days to a few weeks are left between the two eyes. This allows the result of the first eye to be seen, so the target for the second can be adjusted if necessary. Your surgeon decides based on the assessment.
Your Expert Eye Surgeons
Education Information:
After graduating from primary school in Trabzon, Dr. Ofluoglu. He completed secondary and high school in Istanbul. He graduated from Istanbul University Cerrahpasa Faculty of Medicine in 1987. He successfully completed his ophthalmology residency at the Medical University of Vienna, Austria. He received his specialization equivalency in Turkey from Istanbul University Capa Faculty of Medicine . He worked as an Ophthalmologist at Taksim German Hospital between 1997-2014 as an ophthalmologist.Work experience:
German HospitalGalata Medical AcademyCertificates, Memberships, Scientific Publications:
- Articles Published in International Refereed Journals (Sci&Ssci&Arts And Humanities)
- Traenenwege from Die Endeskopie Der Ablrite. Akuchar, P. Novak,
- Ofluoglu FJ: Steinkogler. Spectrum Der Augenheikunde (1985)
- Volumersatz Der Orbita Myth Bioplastic. FJ Steinkogler, A. Kuchar,
- Novak, A.Ofluoglu Spektrum Der Augenheikunde
- Turkish Ophthalmology Association
- European Society Of Cataract And Refractive Surgeons
- American Society Of Cataract And Refractive Surgery
Specialized Treatments and Surgeries:
- Retractive Laser Eye Surgery: iLASIK (Femto Lasik), LASIK, LASEK, TransEpithelial PRK (NO TOUCH) and SMILE
- Cataract Surgery (Smart Lens Surgery)
- Keratoconus Treatments – Cross-Linking Surgeries
- Pterygium – Eyelid (Bird Wing) Surgery-
- Dry Eye Disease and Treatments
- Strabismus Treatments
- Glaucoma- Glaucoma Eye Pressure Treatments
- Diabetic Retinopathy – Treatments for Diabetes-Related Eye Diseases
- Macular Degeneration Disease Treatments
Foreign language:
- English
- German
MEDICAL UNIVERSITY of VIENNA
35 Years of Experience
>35.000 Surgery
Education Information:
He completed his primary, secondary and high school education in Ankara. Fevzi Senturk graduated from Ankara University Faculty of Medicine with a degree in 1994, and subsequently received his Ophthalmology Specialization training from Eskisehir Osmangazi University Faculty of Medicine in 2000. Afterwards, Fevzi Senturk completed his Retina Fellowship at Istanbul Retina Institute and earned the title of Associate Professor at this institution. He is still continuing his academic career by taking the title of Professor at Istanbul Medipol University. He has focused his scientific and clinical studies on retinal diseases, Vitreoretinal surgery and cataract surgery.Awards,Memberships and Scientific Research:
- Retinal capillary hemangioma: AB interno surgical excision, 43rd National Congress Awards, Best Video First Prize, 2009
- Photodynamic therapy guided by indocyanine green angiography in chronic central serous chorioretinopathy, Turkish Journal of Ophthalmology, Best Publication Third Prize, 2000
- Retinal capillary hemangioma: AB interno surgical excision, 43rd National Congress Awards, Best Video First Prize, 2009
- Photodynamic therapy guided by indocyanine green angiography in chronic central serous chorioretinopathy, Turkish Journal of Ophthalmology, Best Publication Third Prize, 2000
- Vitreoretinal Surgery Techniques, Second Edition, Hayat Medicine Bookstore, 2008
- Eye Diseases and Anti-VEGF Therapy 2010.
- Ocular Electrophysiology (TOD Education Publications No 13) Meaning of VEP, VEP registration and parameters in ISCEV standards., 2011
- Clinical Eye Atlas (Oxford Atlases in Ophthalmology), 2012
- Imaging in Ophthalmology, Microperimetry, 2013
- Ocular Electrophysiology (TOD Education Publications 1st Edition), Multifocal Electroretinogram Recording and Evaluation, 2022.
- Current Vitreoretinal Surgery (TOD Education Publications), Surgical Anatomy of the Retinal and Vitreous, 2022.
- Turkish Medical Association
- Turkish Ophthalmology Association
- Turkic Republics Ophthalmology Association
- Electrodiagnostic unit board membership
- Electrodiagnostic unit training representative
- International Society for Clinical Electrophysiology of Vision (ISCEV)
Specialized Treatments and Surgeries:
- Macular Degeneration Disease and Treatments
- Retinal Detachment Treatments
- Retinal Hemorrhages Due to Diabetes and Hypertension and Their Treatments
- Retinitis Pigmentosa Treatments
- Central Serous Chorioretinopathy
- Retinal Vascular Occlusions
- Epirentinal Membrane
- Macular Hole
- Glaucoma eye pressure
- Neuroophthalmological Diseases
- Vitrectomy-Retina Surgery
- Intravitreal Injection Treatments
- Argon Laser Photocoagulation Treatment
- Photodynamic Therapies
Foreign language:
- English
