No anesthesia cataract surgery can be an option

While it is not designed for routine practice, it remains an excellent method for patients with specific indications.

As we all know, the surface of the human eye is highly sensitive. A quick approach, a dust particle or a gust of air to dry out the ocular surface will cause the eyelids to close immediately in a protective reflex. Operating on an eye without any anesthesia seems absurd. However, disregarding all that we know, it is possible.

On June 13, 1998, Amar Agarwal successfully performed the first no anesthesia cataract operation during the Phaco and Refractive Surgery conference in Ahmedabad, India, in front of an audience of 250 people, applying the karate chop technique. During the 1999 American Society of Cataract and Refractive Surgery meeting in Seattle, live surgery was performed in India by Sunita Agarwal, Amar Agarwal and Mahipal S. Sachdev and was communicated via satellite to the meeting in Seattle. All these operations were performed under no anesthesia. The cataracts were removed through a sub 1-mm incision by Sunita Agarwal and Amar Agarwal using a technique called Phakonit. Sunita Agarwal demonstrated laser phacoemulsification, while Mahipal S. Sachdev performed high-vacuum phacoemulsification.

That same year, I had the opportunity to personally attend live, no anesthesia cataract surgery by Amar Agarwal. He kindly offered me the opportunity to perform a live, no anesthesia cataract operation myself. It was a fascinating experience, and even during the operation itself, it was hard to believe that it was really possible.

Back in Munich, I successfully operated two patients younger than 40 years, using this astounding new method. Both were at the patients’ request. Fourteen other cases followed. However, the specific preconditions of this particular group of patients will be discussed later.

Incision

Without any anesthesia, naturally, the incision is much more critical than in routine cataract surgery under topical (retrobulbar, parabulbar or surface anesthesia) or even general anesthesia. The entire procedure is only possible if neither the sclera nor the conjunctiva are touched. In addition, no one-toothed forceps is used to stabilize the eye. Instead, a straight rod is inserted into the eye to guarantee a stable position during the operation.

The first step is essential. A side port is created with a diamond knife, and viscoelastic is injected. This incision is then used to insert a straight rod to stabilize the eye. This is followed by a clear corneal incision.

Capsulorrhexis

The capsule is opened using capsulorrhexis, like in any routine cataract surgery. The capsulorrhexis can be performed using either the needle or the forceps technique.

The needle technique first requires an initial puncture of the anterior capsule within the central area to be removed, which is then extended in a curve-shaped manner. The circular tear is started by either pushing or pulling the central anterior capsule in either direction, while the flap to be created is gently lifted. The next step is to turn over the flap and apply the vectorial forces in tearing with the needle in such a way that a more or less concentrical opening originates. Once the full circle is almost complete, the end will automatically join the beginning of the curve. It is also possible to place the first puncture directly within the planned curvature and start the rhexis with a curved enlargement of this tiny hole. With this approach, the tear is brought around on both sides, until the ends finally join together.

Advantages

--- Even a toric IOL can be implanted using a ring-haptic fixation with a capsular tension ring.

One advantage of the needle technique is that it is economical, because it can be performed with application of balanced salt solution as well as viscoelastics and the cost of the needles is neglectable. The following factors are essential for the success of the needle capsulorrhexis: I highly recommend the use of a 23-gauge needle, because the lumen of this type of needle is just sufficient to produce a pressure exchange between the anterior chamber and balanced salt solution irrigating bottle. The metal of such a cannula supplies just enough rigidity to provide the necessary resistance for difficult manipulations. A higher — that is positive — pressure in the anterior chamber compared with the intracapsular pressure is mandatory. This becomes especially noticeable with intumescent lenses, where the lens protein is hydrated, resulting in a volume increase inside the capsular bag, so that the endocapsular pressure is also considerably increased. Only if the anterior chamber pressure is greater than or equal to that inside the capsular bag can a successful capsulorrhexis be performed.

The pressure in the anterior chamber can be adjusted by varying the height of the infusion bottle. In addition, the needle tip should be as sharp as possible, because a blunt needle may create stellate burst.

The forceps technique is easier. For this reason, it is also the most frequently applied capsulorrhexis technique; however, it can only be performed after viscoelastic instillation. The principle of the forceps capsulorrhexis exactly corresponds to the principle of the needle technique. In addition to the known Utrata forceps, there are mini forceps that are similar in construction to the forceps developed for the posterior segment of the eye. The advantage of these newly designed forceps is that they can be inserted into the anterior chamber via a paracentesis, so that the incision is not exposed to needless strain.

To point out the difference between the needle and the forceps technique, the following example might be appropriate: To turn over a page of a book, you can take the sheet between two fingers and turn it from one side to the other (this is what you do with the forceps) or you can take a moistened finger, press the page down a bit and then turn it over (that is what you do with the needle; the counterhold is the cortex). With this in mind, the consequences are clear. I will always use a needle technique, the initial puncture peripheral or central, for the majority of my cases. I will use the forceps in situations where the needle lacks the other branch. This is mainly the case when liquefied cortex is apparent or secondary enlargement of the capsulorrhexis diameter is necessary.

Phaco technique

A variety of phacoemulsification techniques have been developed with the aim to disintegrate the nucleus in the safest and most efficient way. When Howard Gimbel introduced his divide-and-conquer technique, it was adopted enthusiastically by ophthalmologists throughout the world. For many years after, divide-and-conquer remained the outstanding technique for all nuclei hard enough not to be simply aspirated, until Nagahara presented his new phaco chop technique, the big brother of divide and conquer. Compared with divide and conquer, the nucleus is no longer divided with the phaco tip, but with a second instrument, the “chopper,” so that hardly any manipulations with the tip itself are necessary any longer, thus reducing the risk of damaging the sensitive intraocular structures with the tip.

The phaco chop technique has remained one of the most efficient methods in phacoemulsification. The advantages are obvious. The lens can be divided mechanically into four, six, eight or more pieces. In this process, the originating forces counteract, because the force exerted by the chopper is directed against the phaco tip. The result is that all force vectors go centrally, so that there is no hazard for the lens capsule or the corneal endothelium.

The phaco chop technique is especially suitable for mature cataracts or cataracta nigra, where mostly weak zonulas are found. A beneficial side effect for the surgeon is the ease of work, because the nucleus always can be rotated into the most favorable position. However, an important aspect of phaco chop is that it is only a technique for experienced surgeons, whereas beginners should start with divide and conquer to develop a feeling for the consistency of the nucleus. For the first chopping attempt, a medium nuclear sclerosis should be selected.

To understand the mechanism of phaco chop, you have to consider the anatomic structure of the nucleus, where the crystalline lens fiber runs from one side of the equator toward the opposite side through the center of the nucleus. As a logical consequence, the natural cracking direction follows the lens fiber. As is usual in modern cataract surgery, the capsule is opened with the continuous curvilinear capsulorrhexis (CCC), and hydrodissection is carried out. Then, the epinucleus is aspirated inside the CCC with weak phaco energy. For your first chop, you have to catch the lens with your phaco tip at the 12 o’clock position, advance the phaco tip until you have firm hold of the nucleus and then insert the chopper into the space between the equator and the capsule at the 6 o’clock position.

As the chopper is gradually brought closer to the tip, the nucleus will crack into two halves. Then, the nucleus is rotated 90°, and the inferior heminucleus is cracked into quadrants applying the same principle. If the nucleus is relatively soft, the quarters can be aspirated and emulsified with the phaco tip. In this process, the tip opening should remain in the center of the lens capsule so as not to increase the hazard of damaging either the posterior capsule or the corneal endothelium unnecessarily. When aspiration and emulsification of the inferior heminucleus are completed, the superior heminucleus is rotated 180° and disintegrated accordingly. In the case of harder nuclei, a subdivision of the nucleus into eight or more pieces may be required to prevent residual fragments from escaping into the anterior chamber and damaging the corneal endothelium with their sharp edges.

Experience is essential

--- The ideal capsulorrhexis can be performed using either the needle or the forceps technique.

Experience in phacoemulsification shows that it is beneficial to reduce the overall phaco time and power to the necessary minimum. An additional advantage of the phaco chop technique is that the nuclear matter is first aspirated and then emulsified. In this way, the entire phaco energy is used for emulsification of the nucleus, the aspiration volume concentrates on the nucleus and less phaco energy and time are required, reducing strain for the incision as well as for the corneal endothelium.

The initial phaco chop technique has been modified several times by different ophthalmologists including Nagahara, its inventor. He uses his karate chop technique, which was also applied in the first live, no anesthesia cataract surgery by Amar Agarwal, for cases with poor mydriasis to be able to perform the whole phacoemulsification procedure within the range of the pupil or the CCC. In contrast with the initial phaco chop technique, karate phaco chop goes from the anterior pole to the posterior pole of the crystalline lens. For hard nuclei with a thin epinucleus and the typical dual structure of soft periphery and hard core, Nagahara suggests the crater phaco chop technique. To be able to grab hold of the hard core of the nucleus with the phaco tip, first, a crater is excavated to provide enough space for easy insertion of the tip.

My personal method of choice is the quick-chop technique when performing no anesthesia cataract surgery because of the previously mentioned advantages, such as stress- and pain-free intraocular manipulations.

IOL implantation

Using no anesthesia cataract surgery, I recommend implantation of a soft, foldable silicone or acrylic IOL to be able to make use of the advantages of small-incision surgery, especially because a clear corneal incision is inevitable. The sclera and the conjunctiva must not even be touched. For both IOL families, a large variety of IOL models and types from different manufacturers are available. In this way, it is easy to find a lens to meet the specific requirements of the individual patient. As one of the newest developments, even a foldable toric IOL can be implanted using a ring-haptic-fixation with a capsular tension ring. Foldable IOLs can be implanted with forceps or with an injector, which is the easier alternative.

No anesthesia clear lens extraction

At the Agarwal eye hospitals in Chennai and Bangalore, India, clear lens extraction — also without anesthesia — is applied for the surgical treatment of high refractive errors as an alternative to photorefractive keratectomy or laser in situ keratomileusis, especially in hyperopic or high myopic patients (more than –15 D). Depending on the specific case, an IOL is then implanted or, in cases of extremely high myopia, the patient is left aphakic. The operation follows the same procedure as no anesthesia cataract surgery. For less experienced surgeons, a parabulbar anesthesia is recommended instead of a peribulbar block to avoid the hazard of globe penetration with the needle.

Specific precautions

Experience shows that it is beneficial to cover the cornea with HPMC 2.4% to reduce the surface sensitivity of the eye. In addition, it is essential to maintain the moisture of the cornea throughout the operation.

It is important not to inform the patient prior to the operation to exclude the danger of increased sensitivity caused by the patient’s fear of pain. In addition, it is very important to exclude any sharp or pointed instrument, such as Colibri forceps. However, the use of diamond knives is appropriate.

Furthermore, utmost care with the eyelid is required, because it is experienced as highly disturbing by the patients.

During phacoemulsification, it is very important to only apply low amounts of ultrasound power to avoid the origination of heat, which would be painful for the patient. In addition, the anterior chamber should be well maintained throughout the procedure.

Discussion

No anesthesia cataract surgery is a surprising new development. Without a doubt, the mere existence of this new option is very exciting and might be very helpful in cases with specific indications. However, in my opinion, the different preconditions of patients in different areas of the world need to be briefly discussed. As we all know, a series of amazing phenomena exist in India. What other country has been able to produce individuals who are able to stick knives and sabers through their bodies and faces and pull them out again without a drop of blood and without any wound remaining? On the other hand, documentation of almost unbelievable practices also exist from other areas in the world, like in parts of Africa, where trepanation is performed without any anesthesia, too, and the patients do not feel too much pain when their skulls are opened without any anesthetic relief. On this basis, the no anesthesia approach should be further investigated in terms of its introduction in suitable countries, also taking into account the poverty in large parts of the world, where no anesthesia cataract surgery might be a step in the right direction to improve health care for the population by lowering the costs of treatment.

Generally, in the Western world, this method is only suitable for especially old patients, where the surface sensitivity of the eye is already considerably reduced or for highly motivated patients. In my own practice, I have operated on a total of six patients to date without anesthesia. All of these patients had a mental attitude that enabled them to undergo this kind of procedure and that differs considerably from the majority of the population in any of our industrialized countries. All of these patients asked me to perform no anesthesia cataract surgery, while the majority, especially the younger patients, tend to consider the advantages of general or topical anesthesia instead and would not even dream of having an operation performed without any anesthesia. In this way, the special motivation of my six cases formed the only possible basis for this new approach.

No anesthesia cataract surgery is a highly fascinating new alternative. It is certainly not designed for routine practice. However, it remains an excellent method for patients with specific indications, where our common forms of anesthesia are not possible, for example in hemophiliacs.

For Your Information:

• Tobias Neuhann, MD, can be reached at Marienplatz 18, Munich, 80331, Germany; 011-49-89-230-8890; fax: 011-49-89-230-8991; tneuhann@aol.com. Dr. Neuhann does not have a direct financial interest in any of the products mentioned in this article, nor is he a paid consultant for any company mentioned in this article.

References:

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• Azim Siraj A. Dr. Agarwal´s Homepage Volume II, No. 2: Issues Conference & Seminars: July 1999.
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