Types of intraocular lenses

• Designated to see only either into the distance/medium distance or on close-up.
• For those that do not mind having to use some sort of glasses even having undergone eye surgery.
• The higher quality (aspheric) optics in this lens gives better image and improves the ability to distinguish details (similarly as in high quality cameras).
• Improves vision at dusk which is important for example when driving.
• All of the implants from the TECNIS® line have UV filter.
• The advantage is a simple optical part and with it comes minimisation of side-effects (optical phenomena) with night vision (read more in multifocal implants) – this is a property especially praised by drivers.

Should the patient choose distance vision without the need for glasses, then for all the other distances (computer work, reading) he/she will need an additional correction (+1 dioptre for computer work and +2 dioptres for reading).

In case that the patient prefers close-up vision without the need for glasses, then for distance vision he/she will have glasses with round about −2 dioptres.

• This lens has a filter for blue-purple light on top of also having a UV filter – this is to better protect the retina.
• It is the only lens that filters blue light in such a way that it enables complete transmission of the healthy blue light. Blue light provides improved scotopic sensitivity and is important for healthy circadian rhythms.*

Blue light is responsible for 35% of scotopic sensitivity (meaning vision at dusk). Seeing at dusk is the task of the eye’s rods. Rods do not enable colour vision. Exaggerated restriction of the transmission of blue light may cause worsened night vision and hand in hand with it, an increased risk of falls and night driving.

Many studies support using thus type of implant in patients where degenerative changes in the central part of the retina have already began. It is also recommended in patients with proven family predisposition for this type of disease.

*Circadian rhythm is one of the biorhythms with a period of 20–28 hours, signifying fluctuation of activity and waking in connection with the daily, monthly or yearly period. A nerve path leads from the retina to the centre of the hypothalmus – this is the sensor for light and darkness. This centre is affected by the levels of adenosine and melatonin beside also the intensity of lighting. Adenosine is a substance that origins when using up energy and its increase in the evening hours causes tiredness. In day-time animals, the control of sleep activity and especially its timing is significantly affected by melatonin.

• An entirely new type of refractive monofocal implant.
• Unique construction of the central optical part. It “adds” +1 dioptre.
• Even if this is not a multifocal implant (there are no rings in this implant), it improves distance vision as well as middle distance vision.
• The patient continues to need glasses for reading of miniscule text, but these are of only about +1.0 to +1.5 dioptres.

• A special intraocular lens ideal for the correction of astigmatism or astigmatism with another dioptre error.
• Especially meant for patients with a higher primary astigmatism of up to 5 dioptres (usually 1 to 1.5 dioptres) nor for patients with an astigmatism that is not congenital either post an accident or surgery (for example post transplantation of the cornea surgery).
• Using this implant, we can reach substantially improved vision in patients where another type of procedure is not an option (for example laser eye surgery).

The main principle behind this type of surgery is, similarly as in the previous group, the exchange of own natural lens for an artificial one. The difference is in the actual finish of each implant. The implants have a given exact axis of implantation. The implant is calculated to suit each patient individually depending on his/her axial error and the value of his/her astigmatism.

After the surgery the patient needs glasses for close up seeing in case that a monofocal toric lens was used. A multifocal toric variant also exists where by the patient does not need reading glass.

A risk of rotation of the implant exists in the post-surgery period. Should that happen, the effectiveness of the surgery would be greatly diminished. In such a case, re-operation is necessary to fix the lens back into its correct position.

• This lens has several optical zones that enable a simultaneous image of objects placed in the distance and also in the reading distance of choice.
• Up to 80–85% of all patients are entirely independent from glasses for seeing into the distance as well on close-up after this surgery. The remaining patients use glasses occasionally (for very small text).
• These lenses are not suitable for patients with very high expectations from their vision, for example those who are often active at night.

The disadvantage is a reduced sensitivity to contrasts and the presence of undesired light phenomena (glare and halo – circles around lights). These effects are felt with varying intensity but are present in more or less all patients. Most patients, however, describe a reduced perception of such phenomena in direct in proportion to time passed since the surgery.

A necessary factor in taking full advantage of the properties of this lens is the adaptation of the nervous system to the new image (the so-called neuro-adaptation process). This usually takes 1 to 3 months. In some medical literature you may find even 9 months and more in extremely sensitive individuals.

• For patients with astigmatism of up to 4 dioptres.
• The same basic characteristics apply.
• The front area of the implant has toric spherical surface, the rear area is multifocal.
• The requirements of precision of the implantation of this lens are higher still than with the monofocal version.

• Lens with widened depth of sharpness Extended Depth of Focus (EDOF or EDF) or Extended Range of Vision.
• These make use of new technology that was discovered recently in the treatment of presbyopia and are perceived as the future of this treatment.
• As a result of using achromatic technology they improve the quality of vision at dusk.
• For patients that prefer good quality vision at dusk and in the night and for all active patients and drivers.
• As compared to multifocal intraocular lenses of the EDOF type, these implants work in such a way that they create a single elongated focus that increases the range of vision and the depth of sharpness.
• These may be associated with the undesired so-called photic phenomena such as dazzling or glare around lights (this effect is known as “star burst” in case of the Symfony lens, but it is known that this effect is considerably lower than what it is with multifocal lens).
• In comparison with monofocal and multifocal lenses these demonstrate the same or even better results in vision sharpness into the distance with the tendency to better un-corrected vision sharpness on middle distance (while the multifocal IOL have better results on uncorrected vision sharpness on close-up).

This is why this type of lens is primarily meant for patients that prefer smooth vision from infinity to up to about 40–50 cm. On closer distances and for minor details, a correction of up to +1 dioptre should suffice. However, independence on any correction is, in everyday life, estimated at 90–95%.

• For patients with astigmatism of up to 4 dioptres.
• The same basic characteristics apply.
• The front area of this implant has a toric aspheric surface, the rear area has an achromatic diffractive design.
• The requirements of precision of the implantation of this lens are higher still than with the monofocal version.

• Lens with widened depth of sharpness Extended Depth of Focus (EDOF or EDF) or Extended Range of Vision.
• These make use of new technology that was discovered recently in the treatment of presbyopia and are perceived as the future of this treatment.
• As a result of using achromatic technology they improve the quality of vision at dusk.
• For patients that prefer good quality vision at dusk and in the night and for all active patients and drivers.
• Similarly, as with the Symfony® lens, the Synergy™ lens too enables continual vision with high contrast.
• What is missing is defocusing and the transition between the individual focal points (as we know them in all multifocal implants).
• Here the “halo and burst” effects are significantly reduced as a result of making use of an OptiBlue filter.
• In comparison with monofocal and multifocal lenses these demonstrate the same or even better results in vision sharpness into the distance as well as into middle distance.
• In comparison with the Symfony® lenses these also have better results on uncorrected vision sharpness on close-up.

This is why this lens is primary recommended for patients that prefer smooth vision from infinity to up to about 33 cm.

Independence of the patient from any correction is expected to be, with this implant, somewhere between 95–100 %