Incision

Notes About Incisions

Cataract incisions are essential for good cataract surgery. Do not underestimate the importance of this seemingly easy step. It forms the foundation for the rest of the case and bad technique can punish you throughout the surgery. A poor incision will leak and lead to chamber instability during surgery.

Incisions

As you can see on the initial incision, I make sure that my hand is steadily placed on the forehead above the eye (for right eye) or on the cheek below the eye (left eye), and make the incision without stabilizing the eye with an instrument. I don’t stabilize the eye as I want to avoid any conjunctival trauma that may increase post-operative pain or cause and unnecessary subconjunctival hemorrhage. Generally that works better with the very sharp diamond blades. With the more dull steel blades, it can be necessary to stabilize the eye with a cotton swab or instrument. If stabilization is necessary, it should not cause any conjunctival trauma or risk subconjunctival hemorrhage.

When putting lidocaine + epinephrine in the eye the cannula should be held with the left hand and the plunger depressed with the right. Again the left hand is held stably on the eye using the hand position above. The cannula should be oriented at the exact angle of the incision. Over time, you will develop muscle memory for this angle. Viscoelastic is inserted the same way. You should not move the eye significantly with either cannula. Do not lift or depress the eye as this will burp fluid from the eye which may cause the cannula to hit the lens capsule or the endothelium. It is a very common problem in trainees to lift the cannula in the wound and push the eye down or up into the eyelid and gape the wound. I use Duovisc for my OVD, which is Viscoat (the yellow in Duovisc) and Provisc (green). For the incisions and phaco, I use the Viscoat, which is a dispersive OVD so that it remains in the eye better and coats the endothelium protecting it.

For making the main wound I leave the viscoelastic cannula to stabilize the eye (for efficiency and time to reduce the number of instrument passes with the scrub nurse) and make the main wound with a 2.4 mm keratome. I use 2.4 mm because I believe that the main cause of leaky incisions is stretching the corneal wound rather than wound size. The slightly larger wound allows for less wound stretch with insertion of the IOL. With good technique during the surgery, a 2.4 mm wound will seal easily. The wound should be at the limbus, but not through conjunctiva and should be basically square. I believe that a biplanar wound is better as my experience with triplanar wounds using the femtosecond resulted in a lot of leaky wounds and when I calculate the vector forces on the wound, the triplanar wound seems to be more likely to gape. The wound should be about as long as or slightly less long than it is wide. Be very careful when removing the blade to bring it straight out to avoid cutting the corners of the wound with the blade. Lifting the blade while removing it from the eye can cut the roof of the incision leading to a leaky wound that is difficult to close, even with suture. Also, do not depress the blade as it can cause fluid or viscoelastic to leak from the wound shallowing the chamber and causing the blade to  damage the iris or lens as the anterior chamber shallows with fluid egress. The incision should be made with your fingers with your hand stably positioned on the patient – incisions made with arm movements rather than finger movements are more likely to be poorly controlled.

Note the lack of movement of the eye. The eye should not be lifted or pushed with the instruments and the wound should not gape. Whether or not the eye moves at this stage of the surgery may seem irrelevant, but consider that every movement you make in the eye is reinforcing muscle memory and behaviors. When you are inserting cannulas into the eye for lidocaine or viscoelastic, you are also practicing the technique that you will use in other surgeries to do complex iris repairs, lens exchange, Yamane fixated lenses, and other much more challenging surgeries. If you cannot put a cannula into the eye correctly in this simple step of cataract surgery, then when you are doing a more difficult surgery, you will struggle with eye movement, losing the view, burping out viscoelastic, and other significant challenges. You are always practicing habits – good or bad – in every step of every surgery. Make a commitment now to practicing good habits. There are no unimportant steps to cataract surgery.

Helpful Videos and Links

Video of Incision: https://www.youtube.com/watch?v=cLb7rwATQEA

Injection Lidocaine and Viscoelastic

Capsulorhexis

Notes About Capsulorrhexis

Capsulorrhexis is considered by many to be the hardest step of cataract surgery, however once you master the vector forces of capsule dissection it can be quite simple. Careful three dimensional visualization of the vector forces and good hand positioning and instrument movement will allow mastery of this very important step.

In this video, LBW demonstrates a routine capsulorrhexis. It begins with making a nick in the anterior capsule with the utrata forceps. When using this technique, the forceps must be relatively sharp or with small tips. I make the nick in the capsule with utrata forceps to increase efficiency by reducing the number of instrument passes between myself and the surgical technician.

Capsulorhexis

The capsulorrhexis is started with an incision into the anterior capsule. I make the incision with the utrata forceps, again for efficiency to reduce the number of instrument passes. This does require utrata forceps with small or sharper tips. Some surgical centers have utrata forceps with round tips – in those centers, I will make a small nick in the capsule with the paracentesis blade to give me a defect to start the capsulorrhexis. In cases with weak zonules or when using trypan for white cataracts, I use a cystotome. To make an anterior capsule incision with the utrata forceps push the forceps forward using your fingers into the center of the lens capsule until it breaks through and then extend about 1 mm into the cortex under the anterior capsule. Then lift straight up resulting in a linear tear in the anterior capsule. Grasp the right or left edge of this tear with the utrata forceps depending on the direction of capsulorrhexis you plan to complete. I recommend a clockwise capsulorrhexis, but you should be capable of doing the capsulorrhexis in either direction and some of my colleagues do prefer a counter-clockwise capsulorrhexis. The utrata forceps should be held in your right hand with the index finger of the left hand placed against the side of the forceps to provide a fulcrum and extra stability. When making the capsulorrhexis, there should be very minimal movement of the eye and striae in the cornea should be avoided.

Hydrodissection and Hydrodilineation

Notes about Hydrodissection

Hydrodissection is a relatively safe and stress free step of cataract surgery, but can have very significant pitfalls and if incomplete can lead to significant struggles throughout the rest of the case. Mastery of this seemingly simple step is essential, especially in difficult and unusual cases.

Hydrodissection

This hydrodissection is being performed with a Chang cannula. This is my preferred method, but likely because I trained at the Moran Eye Center where the Chang cannula was the preferred instrument. A straight cannula is acceptable, but the straight cannula uses different positioning and angles to achieve the same goals. I place the cannula at 6 and 12 o’clock for fluid injection. The Chang cannula should not be placed nasally for hydrodissection as one would do with a straight cannula as it will lead to fluid egress around the cannula rather than fluid extension behind the lens. If using a straight cannula, the best location for injection is at about 7:30 and 10:30 on the eye (nasally just above and below straight across from the main wound). The injection of fluid is moderately forceful. It is important with the Change cannula to not move the cannula around or disrupt the cortex and lens very much. Too much distortion will lead to backflux of fluid and loss of OVD in the anterior chamber, rather than hydrodissection. Watch carefully for the fluid wave and stop when the wave is complete. If the lens is too dense to see the fluid, watch for mobility of the lens. It is preferable not to lift the lens through the capsulorrhexis into the anterior chamber in most cases (although there are some techniques of nuclear removal that rely on this). When checking that the lens is mobile, use the Chang cannula pointed downward at the edge of the capsulorrhexis so that there is minimal disruption of the cortex. That will preserve the view of the lens for pre-chopping or other techniques.

Nuclear Disassembly

Notes about Nuclear Disassembly

Nuclear Removal is clearly the important step of cataract surgery, after all, the surgery was scheduled in order to remove the cataract. This is the step at which capsule breakage, vitreous loss, and iris damage among other complications are most common. Mastery of nuclear removal is essential. The ease of nuclear removal will depend partly on proper completion of all of the previous steps and partly on great technique and partly on a thorough understanding of the function of the instruments and phacoemulsification machine.

 Nuclear Disassembly

This video shows nuclear removal with an unsuccessful pre-chop technique that is then converted into a divide and conquer technique using a Connor wand as a second instrument. The phacoemulsification probe first cuts a groove in the lens in sculpt mode. Grooves should be made using full phaco power so that there is no occlusion and thus no post occlusion surge. Then the lens is cracked by holding the right hand hemisection with the phaco and breaking the left hemisection by spinning the Connor wand about 45 degrees on a rotational axis. The rotational movement of the second instrument prevents tipping and incomplete nuclear fragmentation. Rotational movement of the second instrument is then used to turn the lens and repeat the process. Fragments are removed by grabbing the nucleus (not cortex) near the top edge and tipping them forward out of the bag. All of the pieces should be eaten by the phaco low in the anterior chamber to avoid endothelial damage until the final quadrant. Prior to removal of the final quadrant, the nuclear pieces will keep the bag back, preventing damage.

Nuclear disassembly usually begins with separating the nucleus into quadrants or sections through a variety of techniques: (although there are many different variations, I think most fall generally into one of the categories below)

· Prechop: The prechopping technique is usually most useful in cataracts that are mild to moderate in density, although depending on the instrument, some are better for softer and some are better for denser nuclei. A variety of prechopping instruments are available such as the Akahoshi, Imamura, Yeoh, Burrato, Hill, and others. In this technique, the instrument is inserted into the lens center and then divided by opening the tips of the instrument by squeezing the instrument handle. Usually then, the lens is rotated and then a second division is initiated with the same technique resulting in multiple quadrants of nucleus. It is important to watch that the crack extends completely through the posterior lens so that the quadrants are completely separate and can be removed. An advantage of the pre-chop technique is that no ultrasound is used in the division of the lens. A disadvantage is that no material is removed so that there is less space in the central area to pull fragments in with the phaco for removal. I often alleviate this disadvantage by using the phaco to create a small central bowl resulting in free space for pulling the first quadrant out of the capsular bag for removal. Prechop is my primary technique for mild to moderate cataracts.

· Divide and Conquer: This may be the most common technique and is generally thought of as a safe and easy technique for learning surgeons and experienced surgeons alike. I use it any time I have a “difficult” cataract as it is my safest technique. In divide and conquer, the phaco is set to sculpt and then used to create a groove of about 80% depth across the central lens. This groove should be created with the phaco on the sculpt setting and in position 3 (phaco power) fully activated. The purpose of using high phaco power in the sculpt setting is to avoid a circumstance where occlusion occurs that could then result in post occlusion surge. One method of determining the depth of the groove is to cut into the lens until a red reflex is visible in the bottom of the groove. Once a groove is cut, the second instrument (held in the non-dominant hand) is inserted through the sideport incision and used, with the phaco, to crack the lens into two pieces. I recommend using the phaco to hold the half of the lens distal to the sideport and then using the second instrument with a rotational movement in the fingers to crack the lens. The rotational movement with the second instrument is preferred to a pulling movement as it results in a full thickness crack instead of a hinge type crack that can leave the posterior lens uncracked. Once cracked fully, the lens is rotated 90 degrees and the process is repeated creating 4 separate pieces that can then be removed with the phacoemulsification handpiece.

·Vertical Chop: Vertical chop is accomplished by using the phaco to eat into the center of the lens. Once the phaco tip is inserted deeply into the center of the lens, the phaco is kept in position 2 and vacuum is allowed to build. A chopping style second instrument is then inserted distally into the lens near the edge of the capsulorrhexis and drawn towards the phaco and then drawn to the side. The J-shaped motion results in a crack through the lens. Once cracked, then the lens is rotated and this is repeated.

·Horizontal Chop: Horizontal chop is accomplished by eating into the center of the lens with the phaco tip similarly to the vertical chopping technique. Once inserted, a horizontal chopping instrument (an instrument with a smooth and rounded tip) is inserted under the edge of the capsulorrhexis to the periphery of the lens and then drawn towards the phaco instrument. Once cracked, the lens is rotated 90 degrees and the technique is repeated. This technique involves a blind pass into the periphery of the capsular bag and is accomplished by feel and experience. Performed correctly, it is effective at cracking the lens. Overall, this technique may be a little more difficult to learn as it involves putting instruments into areas of the surgery where the instrument tip cannot be directly visualized.

·Femtosecond: The femtosecond laser can be used to create both the capsulorrhexis and dissect the nucleus. The femtosecond laser can be used to create deep cracks in the nucleus in a 4 or 6 piece fashion. These cracks can then be enlarged and extended through the nucleus using a prechopper or using vertical or horizontal chop along the lines created by the femtosecond laser.

·MiLoop: MiLoop is a newer instrument that is useful in breaking the nucleus into fragments. It is very useful especially in dense and hard nuclei and can be used to break these nuclei into fragments without using high amounts of phaco power. Once the lens in hydrodissected, the MiLoop is extended around the nucleus and then the loop is drawn closed in order to cut the lens into as many fragments as desired.

Quadrant removal occurs after nuclear disassembly. Once the nucleus is broken into fragments, those fragments need to be removed. Getting the first and last pieces out are the two most difficult pieces to remove. The first piece I recommend grabbing with the phaco at the top edge of the nucleus (not cortex) at one of the corners and gently engaging the lens in position 2 near the transition to position 3. Then slowly and gently draw the lens into the center of the eye. If in position 3, the phaco will eat the portion of the lens that is being grabbed and likely the piece will fall off the phaco tip. If the piece continues to fall off the phaco tip, consider trying a different piece. If the piece no longer has any good handles, try to take a different piece. Once in the center, keep the piece low against the rest of the lens to remove it with phacoemulsification energy. Because three quarters of the lens is still in the capsular bag, there is minimal risk of the posterior capsule coming forwards during phacoemulsification of the first quadrant. Keeping the piece low results in decreased phaco energy near the endothelium, decreased removal of viscoelastic from the endothelium, and decreased incidence of post-operative corneal edema. Each of the remaining pieces should be removed with a similar technique. The final quadrant should be eaten higher in the anterior chamber (about at or just anterior to the iris plane) to reduce the risk of posterior capsular breakage). When removing the last quadrant, I recommend a technique I learned from Bob Cionni, turning the phaco 90 degrees to orient the fluid port inferiorly to push the posterior capsule back and to point the phaco tip away from the capsular bag.

Very soft nuclei:

·Bowl and fold: In very soft nuclei such as a 20 yr old person with traumatic cataract, I use the phaco or the I/A (depending on how dense the nucleus) to eat a central bowl in the nucleus and then folding the edges towards the center using position 2 (aspiration). As one goes around the edges of the bowl, it will eventually result in the nucleus folding inward and flipping over. Then the remaining nucleus can be removed from the eye.

· Pop and chop: using this technique, the soft nucleus in brought into the anterior chamber with the hydrodissection. Once in the anterior chamber, the I/A or the phaco (depending on the lens density) can be used to remove the lens.

Very dense nuclei:

·MSICS: This topic is covered separately, but MSICS is a very good technique for removing very dense lenses in all locations. MSICS is technically different than phacoemulsification and it can be difficult for phaco surgeons just as phaco can be difficult for MSICS surgeons.

·MiLoop: MiLoop can be used to crack even the densest of lenses and as such can be a good way to divide dense lenses, especially those with a dense posterior plate, for phacoemulsification.

·Phacoemulsification: Phacoemulsification can be used to remove very dense nuclei. Some modifications I recommend in dense nuclei are as follow:

o   Try to do more phaco in the bag and at the iris plane. For this reason I often use divide-and-conquer as a technique because it allows the removal of a good portion of the lens safely in the capsular bag far from the endothelium.

o   Keep quadrants at the iris plane when removing. Using the other fragments of the lens to hold the posterior capsule back, I eat the quadrants right on top of the remaining pieces so that I am as far as I can be from the endothelium

o   Use extra dispersive viscoelastic by refilling the anterior chamber with viscoelastic during the nuclear removal step. This allows the viscoelastic to be replaced on the endothelium during the removal of nuclear fragments. As the surgery often takes longer, the viscoelastic protecting the endothelium can be completely removed by the phaco before the nuclear fragments are completely removed. Reinstalling viscoelastic can protect the endothelium throughout the entire nuclear removal steps.

Other difficult lenses:

·Weak zonules: Consider using capsule hooks or capsular tension ring during surgery to keep the capsule back. Use extra caution to avoid the posterior or peripheral capsule. If vitreous in the anterior chamber, then perform vitrectomy rather than pulling on the vitreous with I/A or phaco.

·Floppy iris: Considuer using iris hooks, malyugin ring or other iris stabilization device. If the iris comes out of the wound, reduce the anterior chamber pressure through the sideport before trying to restore the iris into the anterior chamber. Usually the iris cannot be pushed into the eye and should instead be pulled into the eye using a cyclodialysis spatula from the sideport. Avoid increased pressure in the anterior chamber which will result in iris prolapse when the wounds are burped. Use lower IOP settings with the phaco and I/A. If the iris continues to prolapse, suture the main wound after replacing the iris and make a new incision with adequate length, stabilize the iris with iris hooks or other device and finish the surgery through this new main wound.

Phacoemulsification

Cortical Cleanup

IOL Insertion

Wound Closure

Wound closure is important for preventing endophthalmitis, one of the most feared potential complications of cataract surgery. Skill with this step will result in a well-sealed and elegant closure.

Wound closure with BSS. Generally sutures are unnecessary. Not the hydration of the roof of the wound. This can be done in cases where the descemet’s membrane is well adherent, but caution should be used in environments where blades are dull or where damage to the descemet’s exists