The technique can be performed with any incision. A 5.5- to 6-mm capsulorrhexis is necessary to provide adequate room for later prolapse of the lens nucleus. Hydrodissection is performed with a 27gauge cannula in the usual manner. However, when the fluid wave is visualized and observed to pass entirely beneath the nucleus, rather than stopping, irrigation is continued. In the presence of the large rhexis, fluid accumulation between the capsular bag and nucleus will thrust one pole of the nucleus up and into the anterior chamber. This is the tilt part of the procedure. Employing a second instrument, the tilted pole is rotated to the subincisional location. Emulsification is then carried out, as described above, sequentially rotating the nucleus toward the phaco tip while supporting it with the second instrument. The entire procedure is performed anterior to the plane of the anterior capsule as centrally as possible. Once approximately half of the nucleus has been emulsified, it is flipped to allow emulsification

of the remaining half (Fig. 14–6). This is the tumble part of the procedure. The flipping of the debulked nucleus is easier than flipping the entire nucleus. The greater ease of flipping is the perceived benefit of this procedure over pure phaco flip.

CONTRAINDICATIONS

MATURE CATARACT

The contraindications to this procedure are relative. This first of these is the mature nucleus. The large hard nucleus requires a large capsulectomy. Therefore, the rhexis must be performed even more peripherally. The chance that the rhexis will tear to the equator is consequently increased. This can be precipitated by a chamber shallowing episode or an anteriorally inserted zonule. To prevent this, as well as to protect the cornea during the flip and phaco, a dispersive viscoelastic or a soft shell technique should be employed (see Chapter 24).

FIGURE 14–3 The olive-tipped cannula lifts the former distal pole above the plane of the iris while the opposite pole comes to rest below the plane of the iris.

FIGURE 14–5 The Bechert nucleus rotator is utilized to support the nucleus while phaco is performed at the superior pole.

FIGURE 14–6 Tilt and tumble: partially emulsified nucleus is flipped to provide access to the old inferior pole.

SHORT AXIAL LENGTH

A short axial length eye is another relative contraindication. The crowded anterior chamber will result in the tilting lens being close to or contacting the endothelium, potentially causing significant damage. The lens may be harder to flip, as there is less room to maneuver. Finally, phaco is closer to the endothelium with subsequent damage. The procedure should be augmented, as noted above, with a dispersive viscoelastic or soft shell technique.

FUCHS CORNEAL DYSTROPHY

In patients with Fuch’s corneal dystrophy, although Lindstrom reports endothelial cell loss at 4%, the flipping maneuver as well as the anterior chamber phaco is probably contraindicated. In this setting it is probably most beneficial to choose a phaco technique that locates phaco power as far from the endothelium as is possible.

WEAK OR ABSENT ZONULES

In cases with weak zonules, the flip is best accomplished by flipping the nucleus toward the weak zonules. The stress is then placed on the stronger zonules. A second instrument and viscoelastic (reverse soft shell technique, Chapter 24) can then be used to isolate and protect the area of weakened zonules.

SMALL PUPIL

Small pupil phacoemulsification can be performed with the phaco flip technique. The easiest method of

surgery would be to enlarge the pupil (see Chapter 6). Capsulorrhexis can be performed with a second instrument acting as an iris retractor if necessary. The fluid wave of the hydrodissection is often not well visualized in these cases. By performing the hydrodissection in at least two quadrants and then checking for rotation of the free nucleus, the flip can then be utilized. The rhexis is stretchable and strong if it is continuous. After the flip, the nucleus is exposed in the pupillary space. Often, rotation may be more difficult. There is less exposed nucleus in small pupil cases. Therefore, it may be necessary to begin by applying the phaco tip to the exposed portion of the nucleus only. The phaco tip is retained in the pupillary space and the nucleus can be emulsified in turn. It is important to avoid repositioning the nucleus into the capsular bag as this may compromise the integrity of the capsule.

PROBLEMS

RHEXIS SIZE/HYDRODISSECTION

The rhexis must be at least 6 mm, especially for the surgeon in transition. The hydrodissection must be complete. If the rhexis is too small, or the hydrodissection is incomplete so that the nucleus remains attached to the bag, the entire bag will be flipped with disruption of 360 degrees of zonules.

The larger capsulorrhexis is harder to perform and more likely to tear outward. There is more chance of postoperative IOL movement secondary to fibrosis of the anterior and posterior capsules. This has been noted to be more of a problem with onepiece silicone IOLs.

ANTERIOR CAPSULAR TEARS

There is a high likelihood that the rhexis will tear to the equator during the flip if the anterior capsule is not continuous. Therefore, in this setting, alternative techniques should be employed (see Chapter 5).

Phaco flip can be performed with a tear in the anterior capsule after adequate experience. The rhexis should be large, both to minimize resistance to the flipping nucleus and to minimize stretch on the weakened anterior capsular rim. The axis of rotation of the flip should be approximately in the same axis as the tear in the anterior capsule. If the rotation of the flip is 90 degrees away, the chance that the flipping nucleus will stretch and enlarge the tear is enhanced.

INABILITY TO FLIP

If the rhexis is too small or the hydrodissection incomplete, the nucleus may not flip. In addition,

if the surgeon perceives that the anterior chamber is too crowded, or posterior pressure precludes safe flipping, another category of phaco should be employed.

CONCLUSION

Phaco flip can be utilized for almost every type of cataract. With experience this procedure will generate postoperative clear corneas and minimal significant complications during cataract surgery.

REFERENCES

1.Brown DC. Advanced surgical technique: the phaco flip revisited. MVP Video J Ophthalmol 1999;15.

2.Lindstrom RL. Surgical development: the tilt-and- tumble technique for phacoemulsification. MVP Video J Ophthalmol 1999;15.

The human crystalline lens is a unique structure. It is a cellular structure that loses its innervation and vascularity during fetal development. It derives its nutrition from the surrounding aqueous and vitreous humor. A disturbance in these fluids or in the substance of the lens may lead to metabolic abnormalities, culminating in the development of a cataract.

ANATOMY AND PATHOPHYSIOLOGY

The soft nucleus is usually cortical or subcapsular in nature. Cortical cataracts usually begin as water vacuoles and progress to transparent water clefts between cortical lamellae. The clefts become cloudy as they expand and imbibe water. They may begin peripherally and spread centrally, or as discrete water vacuoles, which proliferate throughout the substance of the nucleus. Histopathologically, water clefts are areas where the cortical lamellae are separated by swollen, degenerate lens fiber debris appearing as anuclear, pink, globular aggregates surrounded by paler pink, granular material. When the whole lens is involved it appears white and is classified as mature. At any point in the maturational process the lens may develop an osmotic gradient as a result of the increase in molecules due to breakdown of proteins. The resultant swelling is termed an intumescent cataract. When the brown endonucleus remains present, the cataract is classified as morgagnian.

Subcapsular cataracts begin as a subtle sheen on the anterior or posterior capsule. They progress to white granular opacities and then enlarge to form a plaque of vacuoles and crystals. The plaque may

thicken. Histopathologically, this type of cataract is associated with posterior migration of lens epithelial cells. The cells then become larger, more spindled, and fibroblast-like. These cells then surround the liquefying posterior cortex in a ring.1 The abnormal lens epithelial cells may then grow into the posterior capsule, causing a ring-like posterior capsular fibrotic plaque. The plaque is fused to the posterior capsule and cannot be removed surgically without tearing the capsule. When it is present, rather than attempt operative removal, the plaque should be polished intraoperatively as best as possible, and the procedure completed. Yttrium-aluminum-garnet (YAG) capsulotomy can then be performed as early as 2 weeks postoperatively, although a longer period of observation is advantageous to allow stabilization of the blood–aqueous barrier prior to laser. Posterior subcapsular cataracts are associated with diabetes mellitus, topical or systemic steroid use, trauma, inflammation, and irradiation.2,3

A unique type of posterior subcapsular cataract is the posterior polar cataract (Fig. 15–1). This cataract is often inherited as autosomal dominant.4,5 In this type of cataract a dense white opacity occurs adjacent to the central posterior capsule. The opacity may be stationary or progressive, with cortical extensions. Concentric thickened rings around the central opacity give the impression of a bull’s-eye.6

The posterior capsule beneath the opacity is reportedly thin and prone to rupture. Osher et al7 report that one-quarter of these cataracts are associated with capsular rupture. Dense white satellite opacities adjacent to the bull’s-eye may indicate a preexisting capsular dehiscence.8 Calcification is an