Intraocular lenses

Modern cataract treatment technique — intraocular lenses

Currently, the surgical procedure for cataract treatment involves removing the patient’s opacified lens and replacing it with an artificial intraocular lens (IOL). IOLs represent a highly advanced technology, both in terms of correction power and the quality of vision they offer. Multiple types of IOLs are now available, allowing for clear vision within one, two, or all three distance ranges:

• near — approx. 40 cm (reading)
• intermediate — approx. 80 cm (working on a computer)
• distance — above 100 cm (spatial orientation)

Intraocular lenses can simulate the refractive properties of a natural crystalline lens, but they are not capable of accommodation. However, research on “accommodating” IOLs — which could change their shape, and thus their optical power, with the movement of the ciliary muscle — is well underway. There is also a range of advanced intraocular lenses suitable for various patients’ needs. Depending on the design, these IOLs can offer additional benefits, such as better contrast sensitivity.

IOLs are typically made of a soft, synthetic, biocompatible material. An average IOL can be between 11 and 13 mm in diameter, and its thickness depends on the refractive power. Lens power is calculated individually for a patient, and can be different for each eye. As IOLs are transparent, you can neither see it nor feel it in your eye.

Types of intraocular lenses

Various types of intraocular lenses are available. In general, standard and advanced IOLs can be distinguished. The latter are also referred to as premium IOLs.

Standard IOLs are the most commonly used lenses in cataract treatment. They have a single focal point and can improve near or distance visual acuity. Therefore, they are called “monofocal” IOLs. To see clearly at other distances, the patient still needs to use glasses.

Advanced IOLs offer additional benefits, beside the elimination of the cataract. They can reduce dependence on eyeglasses when performing different tasks. Advanced IOLs include the so-called multifocal lenses, EDOF (extended depth of focus) lenses, and lenses with additional features, e.g. aspheric lenses, or toric lenses for astigmatism correction.

Multifocal IOLs have two, three, or even more focal points, and restore clear vision over a larger range of distances, allowing the patient to become independent from glasses. Multifocal IOLs include bifocal and trifocal designs, the latter applying the most advanced technology. Trifocal IOLs offer the greatest extent of independence from glasses, allowing patients to see clearly at any distance without having to wear any lenses. Still, all currently available multifocal lenses may cause dysphotopsias in some patients.

EDOF IOLs are also associated with considerable independence from glasses, while producing fewer undesirable side effects, especially in night vision, compared to multifocal IOLs.

Additional features of premium IOLs, such as asphericity or cylindricity, enable the correction of preexisting vision defects such as astigmatism, as well as some photo-optical disturbances (dysphotopsias). Owing to a special optic design, these lenses can also improve contrast sensitivity and overall image quality.

Advanced IOLs allow patients to become less dependent on eyeglasses, and so they are a good choice for those who lead a more active lifestyle or simply do not feel comfortable using glasses.

Premium IOL implantation is not reimbursed by the Polish National Health Fund. Moreover, Polish law does not allow for making additional purchases with free healthcare services, e.g. paying extra for the premium IOL with your free cataract surgery. This situation puts patients at a considerable disadvantage, preventing them from accessing the latest advances in medical technology.

Multifocal IOL characteristics: Trifocal IOLs

Clear vision at all distances

Trifocal IOLs are the most advanced intraocular lenses available now. They provide clear vision simultaneously at near, intermediate, and far distances. They have been designed to ensure a high degree of independence from eyeglasses to patients who lead an active lifestyle and do not want to rely on glasses.

How do trifocal lenses work?

Trifocal lenses refract light reflected from objects located near, at an intermediate distance, and far from the eye, and focus it in a single point on the retina. This way, the patient can focus simultaneously on objects at different distances, achieving clear near, intermediate, and distance vision with a single lens. These modern IOLs reduce or completely eliminate the need for glasses or contact lenses. Similarly to eyeglass lenses, intraocular lenses are also configured to suit each patient’s individual needs, so as to ensure the best possible visual acuity.

Trifocal lenses in everyday life

Unlike monofocal and bifocal lenses, trifocal lenses also help patients see comfortably at intermediate distances, which is important for such daily activities as working on a computer.

Thanks to trifocal lenses, you can perform many everyday tasks without having to put on glasses. This may include:

• reading
• cooking, cleaning, ironing
• working on a computer
• shopping
• watching TV
• driving
• gardening
• exercising and doing sports

Benefits of trifocal lenses

The main benefit of trifocal IOLs is the ability to see clearly at all distances without glasses.

As a result, the patient might actually never need glasses for everyday tasks.

Trifocal IOLs can also be used to treat preexisting visual defects such as myopia or hyperopia. With a toric trifocal IOLs, astigmatism can be corrected as well.

Trifocal IOLs are also an effective treatment for age-related vision impairment, such as presbyopia, which affects nearly everyone over 40. When undergoing cataract treatment with the use of a trifocal IOL, the patient can have their presbyopia corrected simultaneously.

Patients who wish to dispense with glasses or contact lenses, can accept periodic or rare optical imperfections that may occur with the IOL, and are aware that they might still need reading glasses for longer reading periods (depending on their individual preferences) are the best candidates for treatment with trifocal IOLs.

What should patients know?

As with any innovation, there are certain things to consider when deciding whether a trifocal IOL is for you.

Patients with some eye conditions such as glaucoma,, diabetic retinopathy,, diabetic macular edema,or age-related macular degeneration,may not be eligible for bifocal or trifocal IOLs. Even at their early stages, these conditions may be incompatible with treatment using premium IOLs. It is suspected that these conditions may reduce the benefits of using these types of IOLs or, in some cases (though no compelling evidence has been presented) even offer poorer vision than monofocal IOLs. This is why patients with any of these conditions should consult their ophthalmologist to discuss the benefits and any risks of intraocular lens implantation.

Dysphotopsias

One side effect associated with multifocal IOLs is the higher incidence of visual disturbances and photo-optical symptoms (dysphotopsias), due to the fact that the lens focuses light reflected from objects located at different distances from the eye. These symptoms include:

• Glare occurring under certain low-light conditions
• Halos around light sources at night 

Most people with multifocal lenses describe these symptoms as moderately disturbing, and become accustomed to them over time. However, there is a small group of patients who are unable to adapt to using these kinds of lenses or are particularly susceptible to these side effects.

Reduced contrast sensitivity

Multifocal lenses may also provide slightly poorer contrast sensitivity. This is caused by the dispersion of light, reflected by objects at different distances, reaching the retina through the lens. It is thus necessary to take this slight deterioration of image quality into account when considering multifocal lenses.

Cataract surgery — what happens during treatment?

Surgical cataract removal has been known as a safe and effective treatment method for years. As the most commonly performed surgery in the world, it is a routine, typically outpatient procedure. It takes between 15 and 30 minutes per eye. The other eye is either treated a few days or weeks after the first surgery, or on the same day. Same-day surgery for both eyes requires special conditions, but has certain advantages when multifocal lenses are used, enabling the patient to recover their normal vision sooner.

Below you will find our step-by-step guide, describing everything that happens before and during the procedure: from preparation at home to leaving the surgical suite.

Preparation — on the day of the procedure

On the day of your procedure, there are a few things to remember:

• Do not use any facial creams, make-up, perfume, or aftershave.
• Wear casual, loose-fitting clothing.
• Have a light meal no later than five hours before the scheduled time of procedure, and stay hydrated to keep your circulation stable.
• Arrange for someone to take you home after the treatment.

The procedure usually requires no suturing, which lets you recover faster. After a short observation, you will be discharged.

Surgical cataract treatment stages – what to expect before and during the procedure?

1. Measurements

First of all, a few days or weeks before the procedure, your eye must be precisely measured, so that the ophthalmologist can calculate the correct optical power for your intraocular lens. This is non-invasive and normally does not require the pupil to be dilated (unless fundoscopy is performed at the same time).

2. Anesthesia

Right before your procedure, you receive an anesthetic — in the form of drops, or in very rare cases, an injection. This numbs your eye and ensures that the procedure is completely painless. To keep you from blinking during the procedure, an eyelid holder is placed. Then, your conjunctival sac, eyelids, and the surrounding skin are disinfected using a povidone-iodine solution — if you are allergic to iodine, inform your physician during the preliminary consultation, so that a different antiseptic agent can be prepared.

3. Corneal incision

The surgeon makes a small cut in your cornea, about 2–3 mm long. Through this cut, they will remove your cataract using ultrasound, and insert your intraocular lens.

4. Protection of inner eye structures

To protect all the inner parts of your eye during the procedure, the surgeon injects it with a special gelatinous substance called an “ophthalmic viscosurgical device” (OVD). It prevents damage to the corneal epithelium and other ocular tissues during the procedure by minimizing interaction between these tissues and the surgical instruments.

 

5. Lens capsule opening for IOL insertion

Using a thin scalpel, the surgeon makes a small incision in the capsule, which holds your natural crystalline lens.

6. Phacoemulsification

The cataractous lens is softened and broken up using a small device emitting high-frequency ultrasounds, called an ultrasonic phacoemulsification probe. The emulsified lens is removed from the eye using gentle suction (i.e. by aspiration).

7. IOL insertion

At the next stage, the intraocular lens is gently inserted into the natural lens capsule, from which your own lens has just been removed. Once all incisions are closed, they heal by themselves.

8. Eye protection after the treatment

The surgeon covers your eye with a protective dressing, usually kept on until the first follow-up appointment, which takes place the next day.

Recovery from cataract surgery is relatively short — between a few days and one month, depending on the patient. You may notice a significant improvement in your vision immediately after the procedure, but you could also have some discomfort and blurry vision. It may take a few days for the eye to adapt to the new conditions and start seeing clearly. Bifocal and trifocal lenses usually take a longer time to get used to (adaptation to multifocality), and in some cases, weeks or months may pass before your vision is fully recovered.

For a complete recovery, you must adhere strictly to all aftercare recommendations, and keep all your follow-up appointments.

First steps after the treatment

After your cataract surgery:

• Have someone take you home
• Try having a nap, so that you keep your eyes closed and let them rest for a longer time
• Never rub your eyes when they become itchy
• If you experience discomfort or slight pain, ask your doctor to prescribe you some eye drops or take an over-the-counter painkiller
• At your follow-up appointment, describe all your symptoms in detail.

Right after the procedure

After the procedure, your eye will be covered with a dressing or another protective device. It is usually kept on until the first follow-up appointment, or otherwise, as ordered by your doctor. You may be prescribed eye drops or other medication to prevent infection and control intraocular pressure. Take all such medication exactly as prescribed. When applying eye drops, strict hygiene is required — in the postoperative period, the eye is particularly susceptible to infection. Store the eye drops according to the manufacturer’s instructions (e.g. refrigerated) and only touch them with clean hands. Follow the correct procedure for using eye drops (text in box).

Instructions for using eye drops:   – Always read the information leaflet, including indications and contraindications, warnings, and precautions. – Store eye drops properly (protect both against freezing and overheating e.g. to more than 25°C — improper storage may change their properties!) – Pay attention to the expiration date and the period after opening. Eye drops can be used for a specific time once the packaging has been opened. During this period, you can be sure that the medication is sterile and works as intended. When opening your eye drops, it is a good idea to mark the date on the packaging. – Never touch your eye with the dropper tip, and never touch the dropper tip with your fingers. – Good eye drop application technique ensures safe and effective treatment.

Correct eye drop application technique: 1) Wash your hands thoroughly. 2) Put your fingertip below the lower border of your eye and gently pull your lower eyelid down to form a pocket 3) Tilt your head slightly backwards, look up, and use your other hand to hold the dropper directly above the eye 4)      Wkropl 1 kroplę preparatu do „kieszonki” w powiece (uważając żeby nie dotknąć końcówką zakraplacza oka) 5) Remember not to put drops in the corner of your eye, next to the bridge of your nose. If you do, the drops will drain through the tear duct into your nose and throat, which means the medication will not stay on your eye long enough to work! 6) After applying the drops, close your eyes for 1 or 2 minutes. You can use your index finger to gently press your closed eyelid where it meets the nose. 7) Remember not to blink for a while to keep the medicine from draining into the tear duct. Once you close your eyelids, the medicine will naturally cover the surface of the eye 8) After about 2 minutes you can proceed to the other eye. This way, you can keep the first eye from blinking reflexively when you put drops in the other 9) If you need to take two different types of eye drops, do not apply them at the same time, as they will both get washed away before they start working. 10) If you are having trouble putting drops in your own eyes, ask someone to help, but make sure they have read and understood the above instructions as well. 11) After you have finished, wash your hands again.

Rest helps you recover

In the postoperative period, be sure to rest and avoid activities such as bending over, heavy lifting, or exercising. Do not overstrain your eyes for several weeks. Avoid rubbing your eyes or putting additional pressure on them, e.g. when sneezing. In the first week after the treatment, avoid swimming and hot baths to minimize the risk of infection. Protect your eyes from irritation, e.g. with dirt, dust, or wind, and avoid washing your hair.

Short periods of watching TV or working on a computer are already allowed a few hours after the procedure. Still, for the first few days, remember not to put too much strain on your eyes, e.g. by reading for a long time.

Follow-up

Typically, your ophthalmologist will want to check on your eye 24 hours after the procedure. This follow-up will include an eyesight test, ophthalmic examination, and intraocular pressure measurement. You will receive instructions about eye drop use. Right after the procedure, your vision may be blurry, but it will continue to improve over the first few days of recovery.

Later follow-up appointments are scheduled 7–14 days and 30 days after the surgery, so that the whole recovery process can be monitored until your eye fully heals and your vision stabilizes.

Regular examinations

After the follow-up cycle ends, you should only undergo periodic ophthalmological examinations like you did before the surgery.

If you need to have cataracts removed from both eyes, your surgeon may want to wait a few weeks after your first procedure, and then operate on your other eye once the first one has recovered. But if you are being treated for presbyopia, surgery on both eyes on the same day is indicated. This is more demanding, but ensures faster and fuller visual adaptation.

If you still need to use glasses after the treatment, they should be prescribed four to six weeks after your procedure at the earliest, as the eyes need time to heal, and refraction may still change slightly.

Remember you should immediately notify your doctor if:

• you feel severe pain in the eye
• your eye becomes red again
• you experience unusual headache or nausea
• your eyesight deteriorates significantly,
• you notice flashes of light or considerably more eye floaters.

Complications of surgical cataract removal

Potential risks and side effects:

Surgical cataract removal is a well-developed and documented procedure, considered safe and easy to recover from. Most patients choose to undergo surgical cataract treatment for the following reasons:

• vision improvement
• increased independence, especially when combined with an anti-presbyopia solution such as a multifocal lens

But like all surgical procedures, cataract removal is not free from all risks and side effects. Your ophthalmologist will provide information on any risks and decide if you are eligible for surgical cataract treatment.

General risk and complications:

Surgical cataract removal is among the most commonly performed surgical procedures. Each year, 30 million cataract removals are performed worldwide, including over 300 000 in Poland. Cataract surgery has a very high safety profile in most cases. Complications are rare and usually predictable based on risk factors, so they can be mitigated.

The surgeon’s experience (“measured” in thousands of procedures performed) is known to be crucial to the course of the procedure and avoidance of complications. A surgeon who has performed about 5 000 procedures is considered competent, and over 10 000 — experienced. The choice of your surgeon is decisive when it comes to treatment outcomes. More information on the subject will be included in a separate article.

Approximately 95% of adult patients are satisfied with the outcomes of their cataract removal surgery.

As with other surgical procedures, potential side effects include pain, infection, redness, and swelling. Though the anesthetic eye drops used are effective, pain sensation is individual, and so you may experience periodic pain during or after the procedure. The most dangerous complication after cataract surgery isendophthalmitis — an infection of the interior cavity of the eye.This topic will be discussed in detail here. Conjunctival congestion and edema are common after cataract surgery, but they are harmless and typically resolve with no consequences within 7–10 days. Serious complications are very rare with surgical cataract removal, and even if they do occur, most can be easily treated with medication or resurgery.

To reduce the risk of complications after cataract surgery, the patient should strictly adhere to all aftercare recommendations and report all unexpected symptoms immediately. Before the procedure, each patient meets with the surgeon and anesthesiologist to discuss all relevant details.

Dysphotopsias after the treatment

In some patients, dysphotopsias may occur right after the procedure, including glare or halos around sources of light. Halos are bright rings seen around light sources, such as the headlights of passing cars. They can be more pronounced in low-light (scotopic) conditions, e.g. at dusk. Glare is a symptom associated with exposure to excessively bright light, which impairs vision. Such symptoms typically subside over the course of several weeks or months after the procedure, as the brain adapts to seeing with the intraocular lens (which is called “neuroadaptation”). Most patients do not experience any discomfort due to dysphotopsias. If dysphotopsias occur, you should always consult an ophthalmologist, even if the healing and recovery process has already finished.

Posterior capsule opacification (PCO)

Posterior capsule opacification (PCO) is among the most common complications of surgical cataract treatment. It results from abnormal growth and proliferation of lens epithelial cells on the lens capsule. These cells migrate to the posterior capsule, and if they reach the optical axis, this may impair vision. Certain IOL types (with a hydrophobic material and special shape with sharp edges) may inhibit the development of this complication. This is why the type of the IOL implanted matters – with some IOLs, the risk of PCO is several times lower.Posterior capsule opacification is sometimes referred to as "secondary cataract", as it blurs vision similarly to a cataract, but this is a distinct condition. Once removed, cataracts do not return. The good news is that PCO can be effectively treated with a YAG laser. The procedure can be performed in an ophthalmologist’s office, it takes just a few minutes, is entirely painless, and in most cases, vision improves within a day.

See a video on cataract surgery from the OFTALMIKA ophthalmology clinic:

The Polish “Presbyopia 21” Club is grateful for the content provided to our Platform Partner Carl Zeiss.

The Polish “Presbyopia 21” Club is grateful for the content provided to ophthalmology clinic OFTALMIKA

How to identify a patient’s visual needs?

To choose the best method of presbyopia correction for a patient, we must first understand their specific, individual needs. In each case, a specialist will talk to the patient to assess their visual needs based on their lifestyle, type of work etc., as well as their potential tolerance for a certain degree of inconvenience associated with each correction method. In practice, the right choice depends on the accuracy of the patient history taken, the specialist’s experience in gathering specific information, and the patient’s ability to provide detailed input. This is why all information gleaned this way is typically highly subjective and prone to a variety of errors, which may lead to an incorrect strategy choice and ultimately, patient dissatisfaction. For this reason, a device that monitors and assesses the patient’s visual activity can be very useful.

The Vivior Monitor device

Vivior Monitor is a system that can assist in the selection of intraocular lenses or refractive surgery solutions. This is useful both for the ophthalmologist and for the patient, reassuring the latter that the treatment they are about to receive will be well-suited to their lifestyle and the way they use their vision. The system comprises two main elements: the Vivior Monitor device, which collects data, and a compute cloud, which provides an interpretation of these data to the physician. The ophthalmologist first initializes and prepares the device. The patient receives the initialized Vivior Monitor device with a set of accessories allowing for its attachment to eyeglass frames. Vivior Monitor records the conditions in which the patient uses their eyesight, including lighting, distance from objects, time of day etc. When sufficient data are collected, the patient visits their ophthalmologist again and the data are uploaded into the cloud. Results are returned after a few minutes, and can be used to suggest a therapy best suited to the patient’s needs.

Is Vivior Monitor difficult to use?

The description of the system can make it seem daunting to operate, but actually, most processes are fully automated and the device requires nearly no user interaction.

The patient receives the Vivior Monitor device and accessories with a set of video instructions that show how the Vivior Monitor system works, how to correctly attach it to one’s glasses, and how to use it. All the user has to do is wear the device during their daily activities and charge the battery overnight. Vivior Monitor takes all measurements automatically, and a specialized sensor system recognizes when the patient is active, and when they take the eyeglasses with the device off, e.g. for charging.

Data transfer to the cloud and the subsequent calculations are also fully automated. The ophthalmologist simply runs the companion application, connects the device to their computer, and receives an interpretation of the results after just a few minutes. Findings are presented using graphs and easy-to-read images, which makes them easy to explain to the patient. The lack of human interaction in the data collection and analysis process eliminates a number of errors and misinterpretations that could occur when relying on a standard consultation only.

Limitations of the method

For Vivior Monitor measurements to be accurate, certain conditions must be met. As the key benefit of this solution is the use of objective data, these data must be representative.

To obtain accurate and representative information about the patient’s lifestyle and needs, the Vivior Monitor device must be active for at least 36 hours, which means the patient should wear it on their eyeglasses for several days. As the solution selected by the ophthalmologist and the patient should be suited to the patient’s everyday needs, they should wear the monitor during their regular, daily activities. Measurements should be taken both on weekdays and on the weekend, as the patient’s daily routines are likely to differ. Performing the measurements during atypical times, e.g. when going on vacation, should be avoided, as the data collected will not necessarily reflect the patient’s actual everyday needs.

To ensure reliable results, the patient should put the Vivior Monitor on as soon as they wake up, wear it throughout the day, and take it off at night, when they go to bed. This is likely easier to achieve if the patient already wears eyeglasses every day, as monitoring will start as soon as they put their glasses on. Some difficulty can be experienced by patients who will need to use the 0 D eyeglasses provided with the device, as they will need to specifically remember to put them on first thing in the morning. Wearing the Vivior Monitor device can also be slightly more complicated if the patient uses multiple pairs of glasses — but the box does contain several adapters, so that one can be mounted on each pair, and the device can be quite easily moved from one to another.

The Vivior Monitor device is not waterproof, so it should not be used in heavy rain. This is not usually a problem, as most people try to stay indoors in bad weather, but it is nonetheless a minor limitation when using Vivior Monitor.

First-hand experience from Professor Andrzej Grzybowski

I have tested the Vivior Monitor device myself. The software was easy to initialize, though it did require a computer with the Microsoft operating system (I normally use a Mac). As I do not wear glasses on a daily basis, I had to use the accessory frames provided with the device, which required some self-control, but became easier from the second day onward. The device is lightweight and comfortable to wear. One drawback is that you cannot see if it is turned on — it is supposed to switch on by default as soon as you wear it and has no indicators whatsoever. Of course, this makes the experience more natural, with no signals to remind you about the ongoing measurement. Sadly, in my case, one full day of data was not recorded. In summary, using the monitor was quite simple and required no special conditions. In the figure, you can see a report based on my data, showing that I spent 45% of time using the so-called “mid-range” vision, which includes things like working on a computer. In this case, the correction would have to be completely different than for a patient who spends most of their time using their near vision, e.g. reading.