with a foldable lens and the overall time for the phacoemulsification/intraocular lens insertion is often less than the time it takes to do a nucleus expression with a good cortical cleanup in an open-sky system. Thus, this combination makes a lot of sense. Now, however, one has to deal with a cornea that is unclear, and therefore all tricks on visualization are extremely important if the phacoemulsification is going to be successful.

Here is how I handle the visualization conundrum for the following specific diagnoses.

BULLOUS KERATOPATHY

Bullous keratopathy severe enough to warrant penetrating keratoplasty is very aggravating in regard to visualization! Interestingly, the operating microscope allows better visualization than one might expect, in particular if it is aligned slightly off the direct axis so that the disconcerting reflections are not bouncing directly back into the surgeon’s eyes. An irregular epithelium can often be smoothed out with a cohesive viscoelastic. In cases of advanced Fuchs’ dystrophy, removing the epithelium usually will work surprisingly well. In regard to the light level, higher is not necessarily better, and one must adjust the light for optimal visibility, which can vary during capsulorrhexis and be slightly different during phacoemulsification.

Because there is usually no clear zone of the cornea, it is particularly important that “blind” maneuvers not be carried out with bullous keratopathy cases. Being a fan of the phaco chop, I find that using my chopping instrument to manipulate and move pieces well away from the capsule before any emulsification is carried out is much safer and ensures that the procedure is carried out without inadvertent capsular breakage. This is one time that being near the cornea doesn’t matter. I am always certain about my safe zone when visualization is poor during each step of the procedure! With experience, phacoemulsification can be easy even with significant corneal edema. There are some cases in which the visualization is poor. Therefore, when in doubt, convert to open-sky extracap. I will remove the epithelium and smooth out the anterior stromal surface with viscoelastic prior to advancing to penetrating keratoplasty and open-sky cataract extraction, however, and I find that this final step is often enough to safely be able to carry out phacoemulsification.

STROMAL CORNEAL SCARRING

In almost all instances in advanced herpes simplex keratitis or status post–corneal ulcer, there are variable clear zones of the cornea that can provide excel-

lent visualization. Pick the clearest zone and use that for most nucleus removal maneuvers. In a cooperative patient this procedure is often best done with topical anesthesia so that the patient can maneuver the eye and help with best visualization during the procedure. The beauty of a self-sealing incision is that the retrobulbar anesthesia can be carried out at the end of phacoemulsification for the penetrating keratoplasty without difficulty. Other tricks, as pointed out in the preceding bullous keratopathy section, can be used such as decreasing the light to optimize the view and making sure that incident light is not a problem by tilting the microscope body in relation to the corneal plane.

IRREGULAR CORNEAL SURFACE

(SUCH AS KERATOCONUS)

These procedures can be done with topical anesthesia. Most patients with keratoconus who also have a cataract are older and provide dramatically varying visualization depending on where they are looking and which part of the cornea is used as the window. For most patients, looking slightly below the light and viewing through the superior part of the cornea allows a very good view for lens removal. Most of these cataracts are not advanced and can be removed quite easily. In general, these cases are usually the easiest to carry out by phacoemulsification prior to keratoplasty even when visual acuity is markedly decreased.

EPITHELIAL IRREGULARITY (SUCH AS

AN EPITHELIAL DYSTROPHY)

Although epithelial irregularity is rarely an indication for keratoplasty, it certainly can be a visualization concern. This problem can be encountered in some susceptible patients, especially with topical anesthesia, due to a combination of exposure and marked epithelial toxicity. In many such cases there is a clear view immediately after wetting the corneal surface, but in a matter of seconds the view degrades and can seriously hamper visualization even more than the classical corneal problems already discussed! This problem is very easy to control by a viscoelastic resurfacing of the corneal surface. The technique I have found most successful is to place 15 to 20 microdots of a dispersive viscoelastic (so far I have found Viscoat to be the most effective). These little microdots coalesce with a little balanced salt solution; use the tip of the irrigating cannula with the salt solution to smooth any visible irregularities until there is a clear surface. To maintain this viscoelastic surface, it is important to wet only as needed because frequent wetting can irrigate the surface away

and destroy what you are trying to create. If, however, this surface effect is destroyed, it can always be re-created using minimal amounts of viscoelastic. This technique is much preferable to just putting a glob of viscoelastic on the surface, which produces a lot of irregularity, wastes a lot of viscoelastic, and often takes a long time before it smooths out and allows an undistorted view of the anterior segment. Another advantage to this technique is that it avoids copious topical irrigation, which can wash topical anesthesia away and thereby decrease the overall pain-free time in topical cases!

ARCUS

Some limbal corneal pathologies can be quite profound and result in a large band of extremely poor visualization of the anterior segment. This is a much greater problem for surgeons who approach cataracts from only the superior approach. Flexibility is the key, and the best approaches to this specific problem are from the superotemporal, nasal, and inferotemporal directions to minimize the limbal pathology’s effect on visualization. A temporal approach allows a larger viewing area because the distance from the visual axis to the limbus is the greatest temporally and the least superiorly. A topical anesthetic in a cooperative patient is also very helpful in that the patient can pick a spot to the side of the operating light and usually move this limbal pathology out of the way. If a retrobulbar is used, a two-handed technique using a second instrument through the side port also allows the eye to be moved in any direction with complete control to optimize visualization.

BAND KERATOPATHY

Band calcification is often difficult to judge in regard to the impact it might have on visualization at the time of cataract surgery. Limbal band calcification can be handled as outlined above for the arcus; however, if the calcification approaches and crosses the visual axis, the slit-lamp test is usually the best way to decide whether it needs to be dealt with preoperatively or can be ignored. If looking through the central cornea with the slit beam closely lined up with the oculars, and if iris detail is easily visualized, cataract surgery can be carried out generally without difficulty. All of the pearls already outlined, in particular topical surgery in a cooperative patient, will help ensure that visualization will be safe outside the area of the band. An ethylenediaminetetraacetic (EDTA) scrub is simple and effective; however, if there is any question about what to do, removing the central band prior to surgery is the best approach. Allow at least 6 weeks, in that epithelial irregularity,

even though visualization for surgery might be fine, can throw biometry off. A second advantage to the EDTA scrub is improved biometry, in that very bizarre keratometry readings can occur where the band is present.

With a little experience, phaceoemulsification can be completed successfully and safely for a large array of corneal pathologies, which allows for a safer combined procedure and gives cataract surgeons optimal flexibility of doing cataract surgery where the expected visual acuity from the corneal pathology is still quite good. I am convinced that more and more corneal surgeons will find phacoemulsification the best way to proceed in combined procedures rather than the difficult and often unsatisfactory open-sky approach to cataract surgery.

CATARACT SURGERY IN PATIENTS

WITH FUCHS’ CORNEAL DYSTROPHY

(TABLE 23–1)

This common corneal problem has a female preponderance and is age related, becoming increasingly common in the seventh and eighth decades of life. Although familial patterns do appear, the genetics are still controversial! The clinical hallmark, well known by ophthalmologists, is guttata. These excrescences on Descemet’s membrane are a sign of endothelial stress. More advanced signs are increasing stromal thickness leading to folds in Descemet’s membrane and then frank epithelial edema.5 Moderate to advanced Fuchs’ dystrophy can be diagnosed without difficulty. The problem is that guttata alone does not make the diagnosis of Fuchs’ dystrophy.

TABLE 23–1 FUCHS’ DYSTROPHY

Diagnosis Overt guttata Guttataless

Thickening of posterior collagen layer of Descemet’s membrane

Subtle guttate on careful examination under high slit-lamp power

Previous trauma with decreased cell counts Specular microscopy to confirm diagnosis

Phaco technique

Low flow/low power to create many small nuclear pieces to minimize phaco power

Small capsulorrhexis to isolate phaco energy from endothelium/phaco within the capsular bag

Dispersive viscoelastic BSS+

Minimal irrigation and aspiration (I&A) of viscoelastic at the end of the procedure; Diamox sequel for possible intraocular pressure (IOP) spike

Many elderly patients have guttata and yet exhibit no specular microscopic or pathologic findings of Fuchs’ dystrophy. A thickened posterior collagen layer of Descemet’s is the hallmark of this condition, and, to make things complicated, some cases of Fuchs’ dystrophy thicken this posterior collagen layer in a relatively smooth fashion (so-called guttataless Fuchs’). To the unwary it can be missed entirely as a diagnosis prior to surgery!

Although this discussion may so far seem academic, the coexistence of significant cataract in Fuchs’ dystrophy is so common that there is a real practical concern about what to do with suspicious corneas when a visually significant cataract is apparent. Therefore, we face the two big questions once the diagnosis of Fuchs’ dystrophy is made: (1) When do we just attack the cataract and leave the cornea alone? and (2) What is our best approach in cataract surgery to minimize any endothelial damage?

GUTTATALESS FUCHS’

Before exploring these two questions, guttataless Fuchs’ warrants some discussion because it can be a difficult reminder of how fickle the cornea can be. I have seen several cases from excellent cataract surgeons who state that they have used their usual technique with unexpected profound corneal edema, which later was shown to be due to Fuchs’ dystrophy. I have never seen a case of guttataless Fuchs’ that did not have other indications of a problem, often with a lot of subtle guttata. What I have seen, however, on cursory examination could easily have been missed. Many of these patients have gone on to penetrating keratoplasty, and the diagnosis of Fuchs’ dystrophy can be verified. Part of the routine corneal slit-lamp examination should include a careful high magnification scanning of the endothelial surface looking for subtle guttata. Some Descemet’s folds and increased stromal thickness are other warning signs. In this case an ounce of concern can lead to a prepared and much happier patient and surgeon!

A related condition is severe blunt trauma that has compensated and results in a normal-looking cornea. If the cataract looks traumatic, it is well worth a little discussion with the patient on the subject. Some of these patients may have had trauma when they were so young that they don’t remember the event. For example, my uncle was counseled about his cataract, and I was certain trauma had occurred. It was my father who remembered hitting him in that eye with a snowball with a rock in it when they were children. Interestingly, with specular viewing, the endothelial count was substantially decreased in this eye—a fact well worth knowing prior to surgery.

Trauma can result in a profound decrease in endothelial density. In fact, routine specular microscopy may be indicated simply to rule out these outliers prior to surgery, although the opposite case can be made—that outliers are so infrequent they are not worthy of a routine reimbursement. But it is good to know ahead of time what we are dealing with, and in regard to my cataract technique, I treat such cases as though they had Fuchs’ dystrophy.

In answering the question of combined approach versus cataract surgery alone, what do we do with such corneas? The key is to remember that penetrating keratoplasty results are quite good, but the recovery is prolonged, and spherical and astigmatic errors are still common. Although it does definitively get at the corneal problem, it is a significantly more difficult postoperative travail for the patient. Also, we now have cataract removal techniques that create minimal additional corneal damage and therefore are much less likely to tip the patient into significant corneal edema. My approach is very simple: If there is no epithelial microcystic edema other than minor early morning changes that resolve spontaneously on their own shortly after arising, I proceed with a phacoemulsification and intraocular lens (IOL) insertion alone regardless of the corneal thickness. Many patients do well with this approach. Many patients in whom I previously did penetrating keratoplasty are now successfully handled with acceptable visual acuity results by cataract surgery alone. A careful informed consent discussion should include that a corneal transplant is possible as a secondary procedure. The key is performing cataract surgery in ways that will minimize the endothelial damage.

My present approach avoids a long, clear corneal incision in that all of the endothelium near such incisions is usually destroyed and there are no endothelial reserves to heal such a problem. Unfortunately, I have had Fuchs’ dystrophy cataract cases where the cornea has cleared well, but continued profound wound edema has resulted in prolonged patient discomfort. I feel a posterior limbal or sclerocorneal approach has advantages. Such cases are also best served with a dispersive viscoelastic that retains a layer of endothelial protection throughout the procedure. I have generally been very pleased with the use of Viscoat because of its excellent dispersive and retentive capabilities. It leaves a permanent layer on the corneal endothelium, which I do not touch even at the end of the procedure! The cornea is also best protected by minimizing my emulsification time and irrigation amounts.

With normal corneas, prolonged irrigation and phacoemulsification energy in and of themselves do not damage corneal endothelial cells.6 However, I am convinced that Fuchs’ endothelium is different and that prolonged irrigation and phacoemulsifica-

tion times are very dangerous. I believe in lower flow (20 mL per minute or less) and very rapid cataract surgery as keys to avoiding endothelial damage. I am particularly impressed with the phaco chop as a technique to remove the nucleus, with extremely minimal phacoemulsification energy as the best technique to preserve endothelial integrity.7 In cases of Fuchs’ dystrophy, I will chop the nucleus into very small pieces (20 or more) so that only a slight burst of phacoemulsification, and in many instances no phacoemulsification energy at all, is used.

Small capsulorrhexis size (3.0 to 3.5 mm) is an advantage so that turbulence is largely limited to the capsular bag. I try to keep my maneuvering and irrigation inside the capsular bag and after the IOL insertion enlarge the capsulorrhexis if necessary. Another step I take is using BSS+ rather than BSS alone, although I feel plain BSS is more than sufficient under other circumstances. The extra advantage of glutathione as well as other nutrients may be an advantage where endothelial integrity is already compromised.

For IOL insertion it is key that there is a deep anterior chamber produced by viscoelastics and that IOL manipulation occurs well away from the corneal endothelium. Under almost all circumstances this should be a step that adds no additional damage to the cornea.

As a final step, I am not nearly as aggressive in removing viscoelastics, particularly the shell that is near the cornea. I’ll often put these patients on oral carbonic anhydrase inhibitors at the end of the procedure in that some pressure spiking secondary to retained viscoelastic may be more likely, which is also an excellent indication for a longer acting intraocular miotic at the end of the procedure. These corneas can be surprisingly clear the next day if we are meticulous in our surgical detail. I am absolutely convinced that phacoemulsification is the safest way to proceed in Fuchs’ dystrophy, and the corneas look much better with the approach as outlined than doing a planned extracapsular extraction. I know this is quite a paradigm shift from the not-too-distant past when Fuchs’ dystrophy was considered an absolute contraindication for phacoemulsification. We all know that we can easily tip these corneas over with our cataract surgery approach if we are not extremely careful!

PROBLEMS WITH DESCEMET’S

MEMBRANE (TABLE 23–2)

The basement layer of the corneal endothelium is quite inelastic and extremely strong. It is clearly much thicker and tougher than the anterior capsule, and therefore resistant to tearing in most cases. Nonetheless, a tear near the wound and a significant tearing or stripping of Descemet’s with large detach-

TABLE 23–2 DESCEMET’S MEMBRANE

PROBLEMS

Prevention

Use sharp instruments (diamond or new metal) to create incision and incise Descemet’s membrane

Management

Prevent enlargement during insertion of: Phaco tip

Intraocular lens (IOL)

If the wound is tight, enlarge

If the tear is on one side, enlarge opposite side

Insert the phaco tip parallel to the wound—do not lift the tip on insertion

Use viscoelastic in the wound to open it and provide room for phaco tip insertion

Prior to IOL insertion, enlarge the wound Treatment

Single tear on one side of the wound less than 2 mm from the visual axis

Irrigate closed through the paracentesis and ignore Double tear will scroll

Attempt irrigation; if successful, ignore

If unsuccessful, do viscoelastic reattachment Three full-thickness sutures

Leave viscoelastic; treat for potential intraocular pressure (IOP) spike with topical beta-blockers and CAO inhibitor

Giant, or more than three-quarters of Descemet’s is detached

SF6 bubble

ments are not uncommon clinical problems associated with cataract surgery. Like so much else in medicine, prevention is the key in that just like capsulorrhexis, small tears tend to extend into large tears!

To gain access with a self-sealing incision, phacoemulsification incisions cut through Descemet’s membrane. A clean cut through Descemet’s membrane with a sharp instrument, be it metal or diamond, is one of the keys to avoiding further complications.

Almost all tears occur anterior to the entry wound into the anterior chamber. Tears that occur at the time of the incision are almost always due to an instrument or technique failure. One cause is sweeping, either anteriorly or posteriorly, as we start to enter Descemet’s membrane. This is easier to do than one might imagine in our creation of a relatively long tunnel and self-sealing incision. With a sharp instrument, even with movement as we enter Descemet’s, it is hard to create a tear; therefore, when a tear occurs it is most commonly created by a dull blade, be it diamond or metal. However, reused metal instruments are probably the most common cause (Fig. 23–2).

If tears occur at the time of the incision even with a sharp instrument, videotaping the technique so it

can be critiqued should help in making changes in the future that obviate this problem. Even small tears are a potentially much bigger problem later.

Most anterior tears are an insertion problem created by catching the anterior Descemet’s lip whenever an instrument is inserted into the eye. Due to the small size of the irrigation and aspiration (I&A) tip, it has been my experience that it is difficult to create a tear during this phase, and therefore it usually occurs when the phacoemulsification instrument or IOL is inserted into the eye. The unfortunate scenario is a small tear created at either the time of incision or the phacoemulsification instrument insertion (Fig. 23–3) and then significantly extended during phaco, with the movement of the phaco tip or irrigation, or later, with IOL insertion (Fig. 23–4). This is also much more common with a very tight wound and difficult insertion at any time. The following are some general rules for avoiding anterior tears:

1.Don’t fight a very tight wound! If insertion is difficult, it is much better to enlarge the wound at that time. An exceedingly tight wound is also a

FIGURE 23–2 A dull blade piercing Descemet’s membrane and pushing it away from the stroma.

problem in regard to inflow difficulties (pinching the sleeve), which can result in chamber depth fluctuations and phaco burns! As we torque the instrument inside the eye, tight wounds also often result in a lot of visual distortion due to wrinkling of the cornea; therefore, there is no advantage to an overly tight wound.

2.Insert the phaco instrument parallel to the wound plane. Although this may be self-evident with chambers that have collapsed, it is not uncommon to lift up in order to avoid the iris. I think this is a very common way that small anterior tears occur. A little viscoelastic just inside the wound, allowing room to enter the eye parallel to the incision, is one way to avoid this problem, especially when there is a small tear and we do not want to enlarge it!

3.Because catching on the anterior lip is the real problem, I always purposely push slightly posteriorly as I enter the wound to try to avoid putting pressure on that anterior cut edge of Descemet’s. We can often feel the resistance as we enter and engage the anterior Descemet’s edge.

FIGURE 23–4 When irrigation is applied, irrigant flows into the cleavage plane between Descemet’s membrane and the stroma. This is one scenario that may lead to a large or giant tear.

Relieve this pressure by pushing posteriorly and actually feel Descemet’s pop over the front edge of the sleeve, thereby avoiding a tear.

4.Remember that it is the small tear that becomes the big tear, so we need to be extra cautious if we notice a tear. I find it well worth opening the incision on the side of the wound opposite the tear to avoid additional pressure on that edge with the wound. Now is the time to be extra careful about each maneuver as we go through the wound to avoid extending this tear.

Creating a tear with IOL insertion also comes from trying to put too large a lens through too small a wound. Watching videotapes of some insertion techniques as they seesaw their way through this extremely tight wound is a potential recipe for a large tear disaster. Generally, even under these circum-

FIGURE 23–5 The blade creates a single tear in Descemet’s membrane.

stances, just a small tear is created, and a large tear occurring means there has already been a small one in place. All the previous rules already mentioned apply, but in particular be concerned about the overly tight wound. It only takes a second if the wound is too tight to enlarge it slightly.

What do we do when we already have a tear and therefore it is too late for prevention? Most often it is a single tear on one edge of the wound (Fig. 23–5), and as long as it is more than 2 mm from the visual axis, I have been able to irrigate it closed through the stab incision using balanced salt solution at the end of the procedure. It always looks fine the next day and the endothelial pump will keep the tear attached. The only damage done under these circumstances is usually to the surgeon’s ego, except for the fact that such wounds do not “self-seal” as easily and rarely also require a suture.

A double tear on both ends of the wound is fortunately harder to create but unfortunately presents a bigger problem (Fig. 23–6). Often one side of the tear will scroll up near the visual axis and a single tear