6.5 Capsulorhexis

6.5Capsulorhexis

Mark Packer, I. Howard Fine,

and Richard S. Hoffman

Core Messages

ßControl is the key to a successful capsulorhexis.

ßMaintaining the depth of the anterior chamber by utilizing a 1.4 mm clear corneal incision,

which does not allow the egress of the viscoelastic, facilitates control.

ßExquisitely precise microforceps aid the surgeon in designing a superior capsulorhexis.

Enhanced control and increased flexibility constitute the two preferred reasons to initiate and complete the capsulorhexis through a 1.4mm trapezoidal clear corneal incision with microforceps (e.g., 23 gauge curved FineHoffman Capsulorhexis Forceps, Catalog # DFH-0002, Microsurgical Technologies, Redmond, WA). The micro incision capsulorhexis technique is started with radial paracentesis incisions in the superior and the inferior temporal quadrants, constructed with a trapezoidal diamond (e.g., Packer Bimanual Phaco Diamond Knife, Catalog # AE-8141, ASICO, Westmont, IL). These symmetric incisions measure 1.4mm internally, precisely the size required for 20 gauge instrumentation such as the ones used for biaxial micro incision phacoemulsification. The trapezoidal shape of the incisions permits a wider range of intraocular motion without stretching the corneal tissue and prevents the wrinkling and folding of the cornea that impedes a clear view of the capsule.

We feel that the advantages of learning biaxial micro incision phaco outweigh any increased difficulty that may occur during a surgeon’s early experience with the technique. These advantages include enhanced chamber stability due to a more perfectly closed system,

M. Packer ( )

Oregon Health & Science University, Drs. Fine, Hoffman and Packer, 1550 Oak Street, Eugene, OR 97401, USA

e-mail: mpacker@finemd.com

better followability due to the separation of infusion and aspiration, access to 360° of the anterior segment with either infusion or aspiration (made possible by switching instruments from one hand to the other), the ability to use the flow of irrigation fluid as a tool to move material within the capsular bag or the anterior chamber (particularly from an open-ended irrigating chopper or manipulator), and significantly decreased chance of vitreous prolapse in the case of a posterior capsular tear or rupture due to the maintenance of a pressurized stream of irrigation from above.

In order to reap the benefit of these advantages, strict attention to detail is required. The first technique to master, is the construction of the incision; the second is the construction of the capsulorhexis. There is variability in the incision size among surgeons who employ biaxial phaco; 19 through 23 gauge instrumentation has been described. Twenty gauge is preferred here since it offers the right balance between control and efficiency. Because the outer diameter of the 20 gauge tip is approximately 0.9 mm and the circumference of the tip is 2.8 mm (2pr = 2°× 3.14°× 0.45), the incision should measure 1.4 mm. An incision smaller than 1.4 mm in width will stretch or tear, causing loss of self-sealability. These micro incisions are converted from a line to a circle by the introduction of the phaco tip and the irrigating chopper, and we want them to resume the configuration of a line when the tip is withdrawn. Compromise of the corneal collagen by stretching or tearing will reduce the likelihood that the incision will resume its native architecture at the end of the case. Diamond and metal knives specially designed for construction of these incisions are now available from a variety of manufacturers. It behooves the surgeon to purchase and learn to use this instrumentation, whether constructed of steel, diamond or other material.

Capsulorhexis construction represents the greatest hurdle in the biaxial surgery learning curve. This technique was initially begun with a bent-needle cystotome, and this continues to represent a viable approach. However, micro incision capsulorhexis forceps permit a greater degree of precision and control. The pinch type initiation of the capsulorhexis is particularly valuable in cases of zonular compromise since the forces acting on the capsule remain balanced (Fig. 6.44). Even with a severely wrinkling capsule due to traumatic zonular dialysis or pseudoexfoliation, these extraordinarily delicate forceps permit exquisite control of the capsulorhexis.

Fig. 6.44 The tips of the microforceps are touched to the anterior capsule surface with just enough pressure to cause slight dimpling; squeezing the handle tines then pinches the capsule and initiates the tear

Fig. 6.45 In this large eye (axial length = 30.24 mm, horizontal white-to-white 12.50 mm, anterior chamber depth = 4.00 mm) with a widely dilated pupil, the Rhexis Ruler permits the control of the capsulorhexis size

Following incision construction and instillation of nonpreserved intracameral lidocaine, the anterior chamber is filled with a dispersive viscoelastic which will remain in the eye during high flow, high vacuum chopping techniques. The capsulorhexis is initiated centrally with a pinch and the flap is pulled in a counterclockwise motion. The fellow symmetric incision is always available, in case there is trouble and a need to switch hands, greatly increasing our surgical flexibility. The forceps is held and manipulated with the fingers and thumb like a pencil, in distinction to the wrist motion required for the handling of a standard Utrata forceps. The finger control enables greater precision and finer control of the instrument.

The micro incision forceps also allows excellent control of the capsulorhexis because of their firm grasp and additionally, the small corneal incisions facilitate the control of the capsulorhexis because the viscoelastic does not egress from the eye during intraocular maneuvers. The prevention of viscoelastic efflux means that the chamber remains stable. Pressure in the anterior chamber, on the anterior lens capsule, helps to control the capsulorhexis. It is well known that loss of chamber stability will cause the capsulorhexis to run out towards the periphery. One of the advantages of the micro incision technique is that the chamber remains stable during the completion of the capsulorhexis. This allows for a better control of the size, the diameter, and the position of capsulorhexis.

Newer technology IOLs, which prevent posterior capsular opacification with a square edge or facilitate

accommodation with axial or translational movement, are dependent upon accurate sizing and the position of the capsulorhexis. In general, we desire a capsulorhexis which is smaller in diameter than the lens optic: 4.5 mm in the case of a 5.0 mm accommodative IOL or 5 mm in the case of a standard 6 mm multifocal or single vision lens.

The Seibel Rhexis Ruler (Catalog #DFH-0020, Microsurgical Technologies) offers a good alternative in large eyes with maximal pupillary dilation (Fig. 6.45). These myopic eyes have thin, friable capsules. The hugely dilated pupil removes the key customary landmark for sizing of the capsulorhexis, while the outsized anterior chamber defies adequate filling with OVD. In addition, constructing the rhexis through a standard 2.5 mm incision with Utrata forceps will allow the chamber to shallow, due to the efflux of viscoelastic. Without a solid chamber or any clear boundary, the rhexis will tend to run to the periphery before the surgeon can react. However, by employing a micro incision forceps technique, plenty of OVD and the Rhexis Ruler, this complication can be avoided.

The micro incision rhexis technique does not foreclose the option of standard coaxial phaco. In fact, this instrumentation should be viewed as an enhancement to any surgical strategy. One of the situations in which there is a particular advantage to the micro incision rhexis technique is the opaque mature or intumescent cataract. Of course, the use of a capsule stain such as trypan blue, greatly facilitates the rhexis,. However, the maintenance of pressure in the anterior chamber (again,

Fig. 6.46 The combination of trypan blue capsule staining and microforceps technique facilitates exquisite control of the capsulorhexis construction in this eye with an opaque cataract

because no OVD egresses through the micro incisions) together with the delicate, finely controlled application of the micro incision forceps improves visibility and control, preventing a tear out of the rhexis during construction (Fig. 6.46). The micro incision rhexis technique also facilitates rescue of the aberrant rhexis using Brian Little’s rescue strategy [1]. The advantage of the routine use of micro incision forceps is that there is familiarity with their use while approaching a difficult and challenging situation in which they provide a particular advantage.

Take Home Pearls

ßIn difficult cases, or when the size and position of the capsulorhexis is of paramount impor-

tance (such as when the implantation of an accommodative intraocular lens is planned) the use of a microincision and microforceps is advantageous to the surgeon.

ßUsing a capsule dye as needed permits improved control, and should be considered whenever the

anterior capsule is not clearly visible.

References

6.6Hydrodissection and Hydrodelineation1

I. Howard Fine, Richard S. Hoffman,

and Mark Packer

Core Messages

ßCortical cleaving hydrodissection:

ßCleaves the connections between the cortex and the lens capsule

ßFacilitates mobilization and rotation of the lens within the capsule

ßFacilitates cortical cleanup

ßAdds safety to the procedure by reducing the incidence of capsule rupture occurring during

cortical cleanup

ßHydrodelineation:

ßDivides the nucleus into an endonucleus and an epinuclear shell

ßReduces the portion of the lens that has to be removed with ultrasound energy

ßProvides a cushion, within which cracking, grooving, and chopping are contained

ßProvides a protective cushion that keeps the capsule stretched and reduces the likelihood of

capsule rupture during phacoemulsification

Hydrodissection of the nucleus in cataract surgery has traditionally been perceived as the injection of fluid into the cortical layer of the lens, under the lens capsule, to separate the lens nucleus from the cortex and the capsule [2]. With increased use of continuous curvilinear capsulorhexis and phacoemulsification in cataract surgery, hydrodissection became a very important step to mobilize the nucleus within the capsule for disassembly and removal [3–6]. Following nuclear

1This chapter is an update of the previously published by Fine et al. [1].

1.Little BC, Smith JH, Packer M (2006) Little capsulorhexis tear-out rescue. J Cataract Refract Surg 32(9):1420–1422

I. H. Fine (*)

Oregon Health & Science University, Drs. Fine, Hoffman and Packer, 1550 Oak Street, Suite 5, Eugene, OR 97401, USA e-mail: hfine@finemd.com

Fig. 6.46 The combination of trypan blue capsule staining and microforceps technique facilitates exquisite control of the capsulorhexis construction in this eye with an opaque cataract

because no OVD egresses through the micro incisions) together with the delicate, finely controlled application of the micro incision forceps improves visibility and control, preventing a tear out of the rhexis during construction (Fig. 6.46). The micro incision rhexis technique also facilitates rescue of the aberrant rhexis using Brian Little’s rescue strategy [1]. The advantage of the routine use of micro incision forceps is that there is familiarity with their use while approaching a difficult and challenging situation in which they provide a particular advantage.

Take Home Pearls

ßIn difficult cases, or when the size and position of the capsulorhexis is of paramount impor-

tance (such as when the implantation of an accommodative intraocular lens is planned) the use of a microincision and microforceps is advantageous to the surgeon.

ßUsing a capsule dye as needed permits improved control, and should be considered whenever the

anterior capsule is not clearly visible.

References

6.6Hydrodissection and Hydrodelineation1

I. Howard Fine, Richard S. Hoffman,

and Mark Packer

Core Messages

ßCortical cleaving hydrodissection:

ßCleaves the connections between the cortex and the lens capsule

ßFacilitates mobilization and rotation of the lens within the capsule

ßFacilitates cortical cleanup

ßAdds safety to the procedure by reducing the incidence of capsule rupture occurring during

cortical cleanup

ßHydrodelineation:

ßDivides the nucleus into an endonucleus and an epinuclear shell

ßReduces the portion of the lens that has to be removed with ultrasound energy

ßProvides a cushion, within which cracking, grooving, and chopping are contained

ßProvides a protective cushion that keeps the capsule stretched and reduces the likelihood of

capsule rupture during phacoemulsification

Hydrodissection of the nucleus in cataract surgery has traditionally been perceived as the injection of fluid into the cortical layer of the lens, under the lens capsule, to separate the lens nucleus from the cortex and the capsule [2]. With increased use of continuous curvilinear capsulorhexis and phacoemulsification in cataract surgery, hydrodissection became a very important step to mobilize the nucleus within the capsule for disassembly and removal [3–6]. Following nuclear

1This chapter is an update of the previously published by Fine et al. [1].

1.Little BC, Smith JH, Packer M (2006) Little capsulorhexis tear-out rescue. J Cataract Refract Surg 32(9):1420–1422

I. H. Fine (*)

Oregon Health & Science University, Drs. Fine, Hoffman and Packer, 1550 Oak Street, Suite 5, Eugene, OR 97401, USA e-mail: hfine@finemd.com

removal, cortical cleanup proceeded as a separate step, using an irrigation and aspiration handpiece.

Fine, first described cortical cleaving hydrodissection, which is a hydrodissection technique designed to cleave the cortex from the lens capsule and thus leave the cortex attached to the epinucleus [7]. Cortical cleaving hydrodissection usually eliminates the need for cortical cleanup as a separate step in cataract surgery, thereby eliminating the risk of capsular rupture during cortical cleanup.

A small capsulorhexis, 5–5.5-mm, optimizes the procedure. The large anterior capsular flap makes this type of hydrodissection easier to perform. The anterior capsular flap is elevated away from the cortical material with a 26-gauge blunt cannula (e.g., Katena Instruments No. K7–5150) prior to hydrodissection. The cannula maintains the anterior capsule in a tented-up position at the injection site, near the lens equator. Irrigation prior to elevation of the anterior capsule should be avoided because it will result in the transmission of a fluid wave circumferentially within the cortical layer thereby, hydrating the cortex and creating a path of least resistance that will disallow later cortical cleaving hydrodissection. Once the cannula is properly placed and the anterior capsule is elevated, gentle, continuous irrigation results in a fluid wave that passes circumferentially in the zone just under the capsule, cleaving the cortex from the posterior capsule in most locations (Fig. 6.47). When the fluid wave has passed around the posterior aspect of the lens, the entire lens bulges forward because the fluid is trapped

by the firm equatorial cortical-capsular connections. The procedure creates, in effect, a temporary intraoperative version of capsular block syndrome as seen by an increase in the diameter of the capsulorhexis (Fig. 6.48). At this point, if fluid injection is continued, a portion of the lens prolapses through the capsulorhexis. However, if prior to prolapse, the capsule is decompressed by depressing the central portion of the lens with the side of the cannula, in a way that forces the fluid to come around the lens equator from behind, the cortical-capsular connections in the capsular fornix and under the anterior capsular flap are cleaved. The cleavage of the cortex from the capsule equatorially and anteriorly allows the fluid to exit from the capsular bag via the capsulorhexis, which constricts to its original size (Fig. 6.49), and mobilizes the lens in

Fig. 6.48 Capsulorhexis is enlarged by the posterior loculated fluid pushing the lens forward

Fig. 6.47 Anterior capsule is tented up by the cannula, fluid wave is moving posteriorly, and capsulorhexis is enlarged (arrows = fluid wave)

Fig. 6.49 Return of the capsulorhexis to its previous size after decompression of the capsule

such a way that it can spin freely within the capsular bag. Repeating the hydrodissection and capsular decompression, starting in the opposite distal quadrant may be helpful.Adequatehydrodissectionatthispointisdemonstrable by the ease with which the nuclear-cortical complex can be rotated by the cannula.

Hydrodelineation is a term first used by Anis to describe the act of separating an outer epinuclear shell or multiple shells from the central compact mass of inner nuclear material, the endonucleus, by the forceful irrigation of fluid (balanced salt solution) into the mass of the nucleus [8].

The 26-gauge cannula is placed in the nucleus, off the center to either side, and directed at an angle, downward and forward towards the central plane of the nucleus. When the nucleus starts to move, the endonucleus has been reached. It is not penetrated by the cannula. At this point, the cannula is directed tangentially to the endonucleus, and a to-and-fro movement of the cannula is used to create a tract within the nucleus. The cannula is backed out of the tract approximately halfway, and a gentle but steady pressure on the syringe allows fluid to enter the distal tract without resistance. Driven by the hydraulic force of the syringe, the fluid will find the path of least resistance, which is the junction between the endonucleus and the epinucleus, and flow circumferentially in this contour. Most frequently, a circumferential golden ring will be seen outlining the cleavage between the epinucleus and the endonucleus (Fig. 6.50). Sometimes the ring will appear as a dark circle rather than a golden ring.

Fig. 6.50 The golden ring outlining the cleaving between the epinucleus and the endonucleus is clearly visible

Occasionally, an arc will result and surround approximately one quadrant of the endonucleus. In this instance, creating another tract of the same depth as the first, but ending at one end of the arc, and injecting into the middle of the second tract, will extend that arc (usually another full quadrant). This procedure can be repeated until a golden or dark ring verifies circumferential division of the nucleus.

For very soft nuclei, the placement of the cannula allows creation of an epinuclear shell of any thickness. The cannula may pass through the entire nucleus if it is soft enough and so, the placement of the tract and the location of the injection allow an epinuclear shell to be fashioned as desired. In very firm nuclei, one appears to be injecting into the cortex on the anterior surface of the nucleus, and the golden ring will not be seen. However, a thin, hard epinuclear shell is achieved even in the most brunescent nuclei. That shell will offer the same protection as a thicker epinucleus in a softer cataract.

Hydrodelineation circumferentially divides the nucleus and has many advantages. Circumferential division reduces the volume of the central portion of nucleus removed by phacoemulsification by up to 50%. This allows less deep and less peripheral grooving and smaller, more easily mobilized quadrants, after cracking or chopping. The epinucleus acts as a protective cushion within which all of the chopping, cracking and phacoemulsification forces can be confined. In addition, the epinucleus keeps the bag on stretch throughout the procedure, making it unlikely that a knuckle of capsule will come forward, occlude the phaco tip, and rupture.

Cortical cleanup is dramatically facilitated by cortical cleaving hydrodissection. After evacuation of all endonuclear material, the epinuclear rim is trimmed in each of the three quadrants, mobilizing cortex as well in the following way. As each quadrant of the epinuclear rim is rotated to the distal position in the capsule and trimmed, the cortex in the adjacent capsular fornix flows over the floor of the epinucleus and into the phaco tip. Then the floor is pushed back to keep the bag on stretch until three of the four quadrants of the epinuclear rim and forniceal cortex have been evacuated. It is important not to allow the epinucleus to flip too early, thus avoiding a large amount of residual cortex remaining after evacuation of the epinucleus.

The epinuclear rim of the fourth quadrant is then used as a handle to flip the epinucleus. As the remaining portion of the epinuclear floor and the rim is evacuated from the eye, 70% of the time, the entire cortex is

evacuated with it [9]. Downsized phaco tips with their increased resistance to flow are less capable of mobilizing the cortex because of the decreased minisurge accompanying the clearance of the tip, when going from foot position two to foot position three in the trimming of the epinucleus.

After the intraocular lens (IOL) is inserted, these strands, and any residual viscoelastic material, are removed using the irrigation and aspiration tips, leaving a clean capsular bag.

If the cortex is still remaining after the removal of the nucleus and the epinucleus (Fig. 6.51), there are three options to choose from. The phacoemulsification handpiece can be left high in the anterior chamber, while the second handpiece irrigates the cortex-filled capsular fornices. Often, this results in floating up of the cortical shell as a single piece and its exit through the phacoemulsification tip (in foot position two) because cortical cleaving hydrodissection has cleaved most of the cortical capsular adhesions.

Alternatively, if the surgeon wishes to complete the cortical cleanup with the irrigation and aspiration handpieces before lens implantation, the residual cortex can almost always be mobilized as a separate and discrete shell (reminiscent of the epinucleus) and removed without even turning the aspiration port down, to face the posterior capsule.

The third option is to viscodissect the residual cortex by injecting the viscoelastic through the posterior cortex onto the posterior capsule (Fig. 6.52). We prefer the dispersive viscoelastic device chondroitin sulfatehyaluronate (Viscoat®, Alcon Laboratories, Fort Worth,

Fig. 6.53 Posterior cortex fully draped on top of the capsule and the iris (arrows = edges of posterior cortex are elevated by viscoelastic)

TX). The viscoelastic material spreads horizontally, elevating the posterior cortex and draping it over the anterior capsular flap (Fig. 6.53). At the same time, the peripheral cortex is forced into the capsular fornix. The posterior capsule is then deepened with a cohesive viscoelastic device (e.g., Provisc®, Alcon Laboratories, Fort Worth, TX) and the IOL is implanted through the capsulorhexis, leaving the anterior extension of the residual cortex, anterior to the IOL (Fig. 6.54).

Removal of the residual viscoelastic material accompanies mobilization and aspiration of the residual cortex anterior to the IOL, which protects the posterior capsule, leaving a clean capsular bag.