Fig. 11.1
A small PCR (denoted by an arrow) is seen as an area with bright red glow and demarcated by the darker margins of intact PC
Recognizing the edges of the posterior capsule tear (Video 11.4).
Sudden localized brightening of the fundal glow.
Pupillary snap sign [19] where the pupil dilates and then suddenly constricts during hydrodissection. This has been described in detail later in this chapter [19] (Fig. 11.2).
Fig. 11.2
(a) Peaking of the pupil superiorly due to vitreous incarceration in the wound. (b) The pupil is round after vitrectomy
Sudden deepening of the anterior chamber (AC) due to vitreous prolapse into the AC.
Peaking of the pupil due to vitreous incarceration in the wound.
Wiping the wound with a Weck-Cell sponge will pick up strands of vitreous.
An air-bubble injected into the AC forms multiple bubbles instead of a single large one.
Failure of aspiration and loss of followability (Video 11.5) due to vitreous clogging the aspiration port.
Paradoxical movement of lens matter away from the aspiration port and lateral movement of the nucleus caused by hydration of vitreous surrounding the phaco needle.
Failure of rotation of a previously mobile nucleus due to vitreous entrapment and lack of capsular support.
Turbulence of the nuclear pieces during phacoemulsification due to traction on vitreous.
Tilting of a pole of the nucleus.
Sinking of the nucleus (Video 11.6) or nuclear pieces into the vitreous cavity. This can be dramatic in vitrectomized eyes where the nucleus literally drops like a stone on to the retina.
Feeling of “give way” or snap of the PC with loss of resistance.
It is important to trust one’s intuition during surgery. If there is even a suspicion of a PCR, it is prudent to verify the integrity of the posterior capsule before proceeding with the surgery.
11.3 Stages at Which PCR Is Common and Its Prevention
PCRs can happen at any stage of the surgery, right from creation of the wounds at the start of the surgery to the hydration of the wounds at the close of surgery. One of the authors had a PCR when the assisting nurse accidentally knocked his operating hand during the capsulorhexis. As a consequence, the needle perforated the entire lens and ruptured the posterior capsule! We have also encountered a PCR during hydrodissection when the cannula dislodged from the syringe, bounced off the angle, caused an iridodialysis and then ruptured the posterior capsule. Mercifully, the zonules remained intact in both cases. The highest incidence of PCR is seen during emulsification of the last nuclear fragment, especially in hard cataracts. The next most common occurrence is during posterior capsule polishing followed by cortical aspiration [20].
Here, we will deal with the surgical steps during which PCR is seen and the precautions to be taken.
11.3.1 Wound Construction
Careful construction of the incisions is often neglected by beginner surgeons. The keratomes used should be accurately matched with the diameter of the phaco needle and sleeve. A tight wound pinches the sleeve and reduces the flow of fluid into the eye, while the vacuum remains the same. This leads to an unstable AC and severe surge, increasing the chances of PCR. A tight wound is recognized by the difficulty in maneuvering the phaco tip, corneal striae, and, if not recognized early, by wound burn (Fig. 11.3). Once recognized, the tight wound can easily be increased to the right size with a keratome, and the problem is resolved. A large wound leaks (Fig. 11.4), and unless sutured or the bottle height increased, it causes shallowing of the AC, increasing the probability of PCR. When suturing the wound does not help, the wound is closed with sutures, and a fresh one is created at a new location. Side ports that are leaky either due to large size, short length, or tears of the roof should be sutured before continuing with phacoemulsification.
Fig. 11.3
Wound burn seen as an area of intense whitening of the cornea (a) and retraction (shrinkage) of the outer lip of the phaco wound (b). This is usually a consequence of a tight wound leading to constriction of the sleeve with reduced irrigation. This can lead to shallow AC, surge, and PCR
Fig. 11.4
A large leaking wound with BSS pouring out by the side of the phaco probe (a), and later, the iris prolapsing out (b). This can cause a shallow and unstable AC leading to a PCR. (c, d) The wound being sutured
11.3.2 Capsulorhexis
Improperly made or incomplete anterior capsulorhexis can lead to a host of intraoperative and postoperative complications. A small capsulorhexis is easily damaged during phacoemulsification either with the phaco needle or with the second instrument. A runaway capsulorhexis which could not be rescued could have an extension up to the equator at that point. A capsulorhexis that has been completed with a notch pointing to the outside (Fig. 11.5) is weak and can tear at this point. All these scenarios could, during phacoemulsification, lead to the anterior capsule tear extending across the equator into the posterior capsule causing a PCR. A less experienced surgeon would be better off converting to a manual small-incision cataract surgery (MSICS) or a standard extracapsular cataract extraction. A more experienced surgeon would be able to continue with phacoemulsification using a direct chop technique with minimal rotation and lateral stress on the capsule to try and avoid the tear from extending. It is important to prevent collapse of the AC by adjusting the fluidics parameters and by filling the AC with Ophthalmic Viscosurgical Device (OVD) before stopping irrigation.
Fig. 11.5
(a) Correct termination of the capsulorhexis with the notch pointing to the center. (b) Incorrect termination with the notch pointing outward. The latter can lead to an anterior capsule tear at this point which could extend into the PC
11.3.3 Hydrodissection
Hydrodissection is potentially fraught with danger for a beginner surgeon, and at times even the experienced ones. All of us have at some point or the other experienced that sinking feeling seeing the nucleus sink into the vitreous following hydrodissection. A small capsulorhexis adds to the risk of posterior capsule blow out. The ideal capsulorhexis should be around 5–5.5 mm so that it allows the escape of the fluid injected during hydrodissection, at the same time providing 360° coverage of the optic of the IOL by the anterior capsule margin. For a beginning surgeon, it is prudent to create a capsulorhexis which is around 6 mm in diameter. This makes the hydroprocedures safer and the nucleus removal maneuvers easier.
Howard Fine first described cortex-cleaving hydrodissection in 1992 [21]. A 26-gauge blunt cannula is inserted under the edge of the capsulorhexis, and the anterior capsule is tented up to lift it up from the underlying cortex. Fluid is now gently injected till a fluid wave is seen passing between the posterior capsule and the overlying cortex. At the same time, the entire lens bulges forward. At this point, the central part of the lens is depressed backward with the cannula; the trapped fluid is forced out cleaving the cortical-capsular adhesions at the capsular equator and under the anterior capsule. This maneuver can be repeated 6 clock hours away. Instead of performing a decompression, if more fluid is injected at this stage, either the edge of the lens prolapses out of the bag, or, more disastrously, the posterior capsule ruptures backward. I (SD) use an alternate technique (Fig. 11.6, Video 11.7), where I perform hydrodissection in one quadrant alone. On seeing the fluid wave crossing the midpoint of the lens, I move the cannula to the opposite pole of the lens, and gently nudge the nucleus backward and toward the site of injection. This creates more space for the fluid to escape out of the bag, thus making the procedure safer. In posterior polar cataract (PPC) and in cases of suspected preexisting PC dehiscence, hydrodissection should be abandoned altogether in favor of hydrodelineation, (Fig. 11.7 e) which preserves the cushion of the epinucleus.
Fig. 11.6
Cortex-Cleaving Hydrodissection. (a–c) Injection of BSS under the anterior capsule. The advancing fluid wave between the posterior capsule and cortex is demarcated by arrows. (d) Release of the trapped fluid by pushing the lens backward and toward the site of fluid injection. The fluid escapes anteriorly from all sides, cleaving the cortex from the capsule. (e) Hydrodelineation by injecting BSS between the soft epinucleus and harder endonucleus denoted by the formation of a golden ring
The PC blow out is seen as a “pupillary snap sign,” [19] (Video 11.1) seen as dilatation of the pupil followed by a sudden and brisk constriction. The dilatation is caused by forward movement of the nucleus against the iris caused by the fluid trapped between the nucleus and the PC. The sudden constriction of the pupil happens at the exact time that the PC ruptures, allowing the nucleus to move backward into the vitreous. If this sign is overlooked, the nucleus is highly likely to drop into the vitreous cavity the moment phacoemulsification is started. If the nucleus is still in the patellar fossa or anterior vitreous, one can use a vectis or posterior-assisted levitation (described elsewhere in the book) to retrieve the nucleus into the anterior chamber. The wound is now extended and the nucleus prolapsed out. If the nucleus is in the midvitreous or beyond, it is best handled by a vitreoretinal specialist.
11.3.4 Nucleus Removal
The commonest cause of PCR during phacoemulsification of the nucleus is due to aspiration of the posterior capsule, often the equatorial part, with the phaco tip while removing the last bit of nucleus (Fig. 11.7 and Video 11.4). The second more common cause is due to the capsulorhexis margin getting accidentally cut by the second instrument or with the phaco tip itself [22]. This goes unnoticed most of the time, resulting in the tear extending beyond the equator into the posterior capsule. The former is prevented by reducing the fluidics parameters and injecting a dispersive OVD into the bag before removing the last nuclear fragment. The latter is prevented by staining the anterior capsule with trypan blue before the capsulorhexis, so that the capsulorhexis margin is clearly visible throughout the phacoemulsification, reducing the chances of inadvertent damage to it. If a capsulorhexis tear is noticed early, the tag is torn to complete it into a capsulorhexis again, preventing extensions during further maneuvers. While performing a vertical chop, one should stay within the capsulorhexis. While performing a horizontal chop which necessitates an excursion of the chopper up to the equator of the lens, it is necessary to scrape the surface of the lens while traversing distal to the capsulorhexis margin so as to not cut it.
Fig. 11.7
(a, b) A small round central PCR produced during emulsification of the last nuclear fragment. Vitreous prolapse can be prevented with the use of a dispersive OVD to plug the PC opening
11.3.5 Cortex Aspiration
Iatrogenic PCRs during irrigation-aspiration (IA) and PC polishing (Fig. 11.8 and Video 11.9) can be caused by poor-quality instruments with sharp edges. Hence, it is prudent to check the IA cannulae under the microscope before using them. The PC can get engaged in the aspiration port if high vacuum is used during PC polishing. This can be avoided by using low-to-moderate vacuum and aspiration flow rate (AFR) and by avoiding random movements while aspirating the cortex. Using silicone-tipped irrigation-aspiration handpieces reduces the incidence of PCR during cortex aspiration and PC polishing [23].
Fig. 11.8
(a–c) Polishing the PC with instruments that have sharp edges can produce PCRs. They can also be produced if high vacuum is used during PC polishing and the capsule gets engaged in the aspiration port.
11.3.6 IOL Implantation
Most PCRs during IOL implantation occur due to a sudden uncontrolled ejection of the IOL from the cartridge (Fig. 11.9 and Video 11.10). The anterior chamber should be kept deep with OVD before IOL implantation. If the plunger of the IOL injector is anything but smooth at any stage of IOL implantation, it should be withdrawn from the eye, the IOL reloaded, and implantation re-attempted. An IOL shooting through the equatorial capsule into the vitreous can have serious consequences. Utmost care is needed while implanting three-piece IOLs. Wait for the optic to open fully after inserting the leading haptic into the bag, before dialing in the trailing haptic. The tip of the leading haptic points backward toward the PC before the optic opens, and if the IOL is implanted in a hurry, the tip may pierce the PC (Videos 11.11 and 11.12).
Fig. 11.9
(a, b) PCR seen due to inadvertent forceful ejection of the IOL from the cartridge during implantation.
11.3.7 Wound Hydration
This last step is not without risks. The cannula detaching from the syringe can enter the eye with considerable force, causing complications such as Descemet’s membrane detachment, PCR, IOL dislocation, and iridodialysis. This is avoided by using a properly fixed cannula on a Luer-locked syringe, and if not available, the hub of the cannula should be grasped firmly between the thumb and forefinger of one hand before injecting saline into the wound margins and the anterior chamber. Even if the cannula was to detach itself, it would still be held between these two fingers and not shoot into the eye.
Even after taking these precautions, surgeons will encounter a PCR sometime, and the next section will deal with its management.
11.4 Management of PCR
The surgical strategy to be followed depends on the stage at which the PCR occurs. If the PCR occurs right at the beginning of nucleus management, while sculpting or while performing the first chop, it is prudent to convert to a sutured ECCE at the same site or a sutureless manual small-incision cataract surgery (MSICS) at a different location. When the PCR occurs during the later stages of nucleus emulsification, an experienced phacosurgeon may still be able to continue with phaco, with the use of appropriate OVDs, but a less-experienced surgeon will have to convert.
The normal reaction on noticing a PCR is to immediately withdraw the instruments from the eye. As the irrigation suddenly stops, the AC collapses and the vitreous moves forward through the PCR, thereby enlarging its size. The sequence to be followed (Fig. 11.10 and Video 11.14) on realizing that there is a PCR is as follows:
Fig. 11.10
Sequence to follow on recognizing a PCR during phacoemulsification. (a) Stop phacoemulsification, but keep the irrigation on. (b) Withdraw the second instrument and inject a dispersive OVD through the same paracentesis. (c) Complete emulsification of the remaining nuclear fragment under cover of OVD. (d) Inject more OVD into the AC before withdrawing the phaco tip from the eye.
Stop phacoemulsification and aspiration immediately, but continue with the irrigation. In other words, one should move to position 1 on the foot pedal. The only situation when one keeps the aspiration on (remain on position 2) is when the PC opens up with a nuclear fragment held with vacuum at the phacoemulsification needle. Releasing the vacuum at this stage will cause the fragment to drop through the PCR. In these situations, the foot pedal should be kept in position 2 and OVD injected beneath the fragment, before releasing the foot pedal.
Take an OVD (preferably a dispersive one, but practically any one that is immediately at hand) in the nondominant hand and form the anterior chamber through the paracentesis. If possible, inject the OVD below the nuclear fragment before filling up the anterior chamber.
Once the anterior chamber has been stabilized, the phaco probe can be withdrawn from the eye.
Using the second instrument, move the nuclear fragments into a safe area that is away from the PCR. This would mean moving the pieces to an area of intact capsule or even in front of the iris.
Do not panic and say anything which may increase the anxiety or discomfort to the patient. Words like “rent” and vitreous “loss” are best avoided. Any negative interjection at this stage can also be detrimental.
Take stock of the situation. Check the position and extent of the PCR and at what stage of surgery it has happened. One should make a realistic assessment of one’s ability to manage the situation. One has to decide on whether to continue or seek help of a senior consultant if available. If one is able to continue, one should decide on which route one is comfortable with, that is, to continue with phacoemulsification or convert, type of vitrectomy, choice of IOL, etc.
Perform anterior vitrectomy if needed, complete the cataract surgery, and implant the correct choice of IOL.
The wounds will often require to be closed with sutures to prevent postoperative wound leak which would further compromise an already compromised outcome.
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