Cataract

Before the laser treatment, a contact lens is placed on the eye of the patient. This so-called patient interface will be followed by a last online diagnosis. The laser is centered over the lens of the eye and the eye is measured via a 3D camera system. Thereafter, the treat­ment planning takes place. Within seconds, the system creates a treat­ment proposal that is controlled by the surgeon and modified if necessary. The actual laser treatment steps follow one after the other:

• The circular opening of the anterior lens capsule (capsulotomy)
• The crushing of the natural lens

• Incisions in the cornea are computer-aided and thus more precise
• Correction of existing astigmatism
• High-precision computer-controlled opening of the lens capsule
• simplified removal of the body's clouded lens
• less phaco (ultrasound-) -energy protects the corneal endothelium
• less tension on the zonular fibers of the lens
• less pressure fluctuations during the operation, higher stability of the eye
• Online diagnostics and monitoring of treatment via 3D camera, computer controlled
• Accurate placement of the IOL as the basis for better vision
• if necessary, fine laser correction possible in the clinic (LASIK or PRK)
• if necessary, combination with PTK possible

For the development of surgical tech­niques in cataract and lens surgery, we have already been able to make some innovative contributions to the use of laser technology:

• As early as 1985, the concept of the so-called "laser phaco". The lens is directly comminuted and aspirated via a probe introduced into the eye (patent application 1985 and 1997).
• When using the femtosecond laser corneal cuts and opening and crushing of the eye lens are made via contact optics. Our concept of femtolaser application was developed in the years 2002-2003. Patent applications were filed by us in 2003, 2009, 2013 and 2014.

• Rasch, V.: "LASICAT-Lasers in Catarct Surgery", video contribution to the film festival of the ASCRS, San Diego 2004
• Rasch, V.: "LASICAT-Laser in Catarct Surgery", video contribution at the DOC, Nuremberg 2004
• Rasch, V.: "LASICAT-Lasers in Cataract Surgery", First experience with the LaserSoft, Vortrag ESCRS, Paris 2004
• Rasch, V., Majewski, S.: "Limiting aspects in LASICAT surgery (Femto Phaco)", poster presentation WOC (World Congress) Abu Dhabi 2012

Of the many terms used today for the same procedure of femtolaser-assisted cataract surgery, we use our 2004 propagated term "LASICAT Lasers in Cataract Surgery".

Femto-Phaco + LASICAT were nomi­na­ted for the "Brandenburger Zu­kunfts­preis CAI 2013" in the category "Innovation".

In 2018, we were surprised by the news that Professor Gerard Mourou was to receive the Nobel Prize in Physics to­gether with Cana­dian Donna Strickland for their funda­men­tal work on the femto­second laser. Dr. Rasch therefore took the opportunity to travel to Stockholm with Dr. Korn and meet Professor Mourou at the Nobel Prize ceremony.

▲ Dr. Rasch, Nobel Prize winner Prof. Gerard Mourod and Dr. Korn (from left) at the 2018 Nobel Prize ceremony in Stockholm

With standard intraocular lenses, only in the ideal case an independence of glasses for the distance can be achieved. Vicinity will always require reading glasses. On the other hand, so-called multifocal intraocular lenses of different construction give the patient the possibility of freedom from glasses both for the distance and for the vicinity.

Multifocal lenses come closest to seeing naturally, as with a healthy eye. At work, in sports or in the hobby, wherever the patient relies on good vision in the distance and in the vicinity, these lenses offer a good solution, because glasses can usually be dis­pensed with. However, certain trade-offs in terms of optical quality and visual acuity still need to be made.

Goal of the operation with multifocal lenses

Independence of eyewear for seeing in the far and near, individually especially desired for occupation, in the house­hold, in the leisure time, among other things.

With such multifocal lenses, which have flat zones for distance and near, the far-near effect may be absent with a very narrow pupil (for example, in very bright sunlight). For medium-wide pupils (normal case), a vision in the distance and in the mid-range without glasses should be possible. If the pupil is wide, there may be "halos" or other appearances around lights or objects (e.g., in the dark). However, most patients tolerate this after a few months. For example, professional drivers should therefore refrain from a multifocal lens. Eventually, the contrast vision is lowered. For reading with multifocal lenses of very small writing, reading glasses are still required.

This is possible due to different optical principles.

How certain is it, that the patient with a multifocal no longer needs glasses after surgery?

In the case of astigmatism, there is no focal point in the eye, but so-called focal lines in mutually perpendicular axes. The youthful, healthy eye or monofocal IOL eye can tolerate this to some extent. This is more difficult with multifocal IOLs. If there is an astig­ma­tism of 0.75 dioptres after surgery, there may be visual disturbances, which can be corrected if necessary. But this is individually very different. Sometimes astigmatism also produces shadow vision, e.g. on letters. LASICAT II can already reduce astigmatism during surgery.

A remaining "residual refraction", meaning the spectacle value for the distance, can be reduced by laser treatment of the cornea. This also applies to astigmatism. The additional costs depend on the selected laser process.
Even with mutifocal IOL, visual acuity of 100% (or better) can be achieved without glasses. However, the focal points in the different target ranges are not as sharp as in a healthy eye. Thus, the image on the retina may be a little blurred. This is also noticeable in the intermediate distances.

Other possible restrictions

Since the light is divided from far and near, less light comes into the eye from every distance. This makes the picture seen a bit darker. The contrast vision is reduced. You may need a bit more lighting (for example, when reading) than with a simple, mono­focal IOL or earlier in adolescence. Grayscale in certain texts may be worse recognized. Even when driving at dusk, a contrast reduction can interfere.
With multifocal IOLs, stray light or glare sensations can also occur at the edges or transitions. This can lead to light halos, being seen around lights at night. People who drive a lot at night should therefore not receive MF IOL.

There is also a picture size change by the operation at higher glasses strengths. This is particularly noticeable when replacing a clear lens (CLE), as th expectation of this is higher than in a case of advanced cataract. - In case of hyperopia post­operatively: image reduction, - In case of myopia post­operatively: image magnification. For both refractive errors, the higher the diopters, the greater the effect. Also: when correcting high hyperopia, there may already be a visual acuity reduction due to the smaller image. (The effect was demonstrated.)

The IOLs are usually used in the natu­ral, freed from the lens opacification capsule. If these break during the operation, it may not be possible to implant the planned multifocal IOL. Another model could be useful later.

Occasionally, present or later emerging capsule opacities ("capsule fibrosis") can affect vision on multifocal lenses more than standard IOL. For this reason, it should be checked in the first few months whether a visual gap using the YAG laser makes sense. This treatment is done sitting down, by the way it is covered by insurance.

Both the evaluation of the healing process and the verification of the accuracy of the measurement and implant, and thus also of the quality assurance, must be attended by the patient. With unforeseen complications on the first eye, the planning for the second eye changes. After one-sided operation, there may also be a side difference in brightness and color vision. In rare cases, an explant may even be desired with the exchange for a monofocal IOL.

We need to know that, as in other areas, there are measurement in­accu­racies or tolerances. This - on the one hand - concerns the lens operation the diagnosis (despite multiple measure­ments on different devices), the accuracy of the implants (these are usually graded in 0.5 dioptres), but also the later position of the intraocular lens in the eye. Most of the time, we are aiming for a +/- 0 diopters refraction for the leading eye. The other eye may possibly be planned a bit in minus (monvision or micro-monovision).

Despite all measurements and cal­cu­la­tions before the operation, there may be devia­tions from the target refrac­tion. This is mainly dependent on the distance between the inserted new lens and the cornea (so-called anterior chamber depth). The anterior chamber is lower after surgery than before surgery. The anterior chamber depth can not be accurately estimated or calculated. As a result, in individual cases after surgery, additional correc­tion by glasses may be required for the distance. This is a possible and un­pre­dic­table, individual problem of the eye of a patient, which can occur with all intraocular lenses and is not the responsibility of the surgeon.
In the healing process, the opening size and shape of the so-called Kap­sul­or­hexis can play a role. Therefore, we recommend the use of the femto­second laser (LASICAT) for an exact rhexis, but of course also as a more gentle surgical procedure for all lens operations. Multifocal, multizonal and toric intraocular lenses are only implanted in conjunction with LASICAT.

Contraindications when deciding on multifocal intraocular lenses

Multifocal IOLs are manufactured with high precision. Optical errors in the IOL optics would be more noticeable with these lenses than with standard IOLs. The same applies to limitations in the optics of the eye. Therefore, we implant e.g. no multifocal IOL in a case of...

• corneal scars or
• changes in the corneal endothelium (cornea guttata)

Likewise, there should be no macular changes. Even driving at night is often problematic with multifocal IOL.

In this group of implants, we include those IOLs that do not have a unique far and near point, such as multifocal (bifocal or trifocal) lenses. However, in contrast to monofocal IOLs, they make it possible to see from far away to a "middle" close range, i.e. "multi­zonal". They show good visual acuity, but are mostly inferior to the multifocal lenses at a reading distance of 30-40 cm. There are also different optical principles here. The visual "side effects" and concomitants as with multifocal IOL are usually lower in multizonal IOLs.

If, in addition to the opacity of the eye lens, there is greater astigmatism, Toric lenses are used. They reduce the total astigmatism of the eye and thus the most congenital dis­tor­ted vision. Together with the industry, we de­ve­loped the first "personalized" Toric IOL worldwide. In August 2005 the im­plan­tation of these lenses was started in our clinic.

The goal of cataract surgery is usually a vision without glasses after surgery, thus the achieve­ment of a residual gland value below +/- 0.5 dioptres. In spite of extensive preoperative dia­gnos­tics, improved surgical techniques and precision in the IOL production, especially in the postoperative anterior chamber depth, the causes are the distance of the inserted new lens from the cornea. This can not be reliably predicted despite a thousand-fold observations in individual cases.

A revolutionary further development now solves this problem: the Calhoun Light Adjustable Lens can be "fine-tuned" by precisely metered UV irra­dia­tion even after implantation. This prin­ciple of postoperative correction of an intraocular lens was developed by Prof. Robert Grubbs, one of the Nobel Laureate for Chemistry 2005!

We have been implanting this IOL since June 2008. Since 2011, we have been implanting this IOL in conjunction with additional protective shields in the eye to reduce stray light during UV irra­dia­tion. For this we have filed a patent application.

The eyemax mono is an artificial lens designed specifically for patients with macular disease. The most common cause of macular damage is age-related macular de­ge­nera­tion (AMD). This leads to distortions or to the failure of the central vision and thus the ability to read and to recognize faces.

The eyemax mono supports the ability of the brain to use the most functional areas of the macula for a sharp image. The image seen is not only projected on the macula center(as usual), but also on border areas.

Due to the complex optical surface production, the eyemax mono is located in the high-end premium segment.