Sulcus placement of three-piece lens with optic capture (Figure compliments HV Gimbel)
If the posterior capsular tear occurs during or after lens placement in the bag, then the optic can be captured by the capsulorhexis, leaving the haptics in the bag (reverse-optic capture, see Fig. 17.2).
Reverse-optic capture of lens placed in the bag (Figure compliments HV Gimbel)
The third possibility arises when the pseudophakic lens becomes dislocated posteriorly behind the lens capsule. The optic may be brought up anterior to the anterior capsulorhexis, leaving the haptics behind the posterior capsule (see Fig. 17.3).
Anterior optic capture of lens located posterior to the capsule (Figure compliments HV Gimbel)
126.96.36.199 Intact Posterior Capsulorhexis
In the event of a large or numerous anterior capsular tears, an attempt should be made to convert the posterior capsular tear into a continuous curvilinear capsulorhexis, smaller in diameter than the optic of the lens. Once this is done successfully, the pseudophakic lens can be located behind the capsular bag, in the capsular bag, or in the sulcus, and the optic can be captured by the posterior capsulorhexis (see Fig. 17.4).
Posterior optic capture of lens placed in the sulcus, in the bag, or behind the capsular bag (Figure compliments HV Gimbel)
188.8.131.52 Intact Capsular Membrane
Occasionally, an intact capsular membrane is encountered, either in the presence of aphakia following complicated cataract surgery or with a dislocated lens. A premium three-piece lens can be repositioned or secondarily implanted, provided stability can be ascertained. Options include optic capture if there is an adequate existing opening in the membrane or if a purposeful membrane opening can be enlarged or created (using a vitrector, forceps, or scissors). Capsular membrane fixation of the lens can also be a consideration ; the lens can be stabilized using 10–0 prolene to suture the haptics or optic (if fenestrated) to capsular remnants (see Fig. 17.5).
184.108.40.206 Iris Suture and Scleral Fixation
Iris suture fixation and scleral suture fixation of three-piece lenses have been reported with good outcomes [26–28]. Scharioth has described intrascleral fixation of multifocal lenses with good outcome ; Agarwal et al. have also reported similar good outcomes with multifocal lenses employing glued intrascleral fixation .
(A video from A Agarwal for a glued scleral-fixated multifocal IOL is included in the DVD which accompanies this book)
Iris and scleral fixation techniques have the added advantage that the power of the premium lens does not need to be modified from the power chosen for in-the-bag implantation .
Kenneth Rosenthal has also described a technique in which a three-piece multifocal lens is placed in front of the iris and sutured to the anterior surface of the iris. He uses 10–0 polyester sutures and avoids contact between the haptics and the anterior chamber angle by crimping the distal half of the haptics, so that they bend toward the optic .
17.2.2 Strategies for One-Piece Premium Lenses
Although three-piece lenses may be placed in the sulcus, considerable concern exists regarding the implantation of single-piece lenses into the sulcus. The reported complications of sulcus placement of single-piece lenses include iris pigment dispersion, iris transillumination defects, dysphotopsia, elevated intraocular pressure, intraocular hemorrhage or hyphema, and cystoid macular edema . In the retrospective series of 30 patients reported, 2 experienced one complication; 8 experienced two complications; 13 experienced three complications; 4 experienced four complications; and 2 experienced five complications. Twenty-eight eyes (93 %) required surgical intervention, and lens exchange was performed in 25 (83 %). The likely reason for such high complication rates is the instability of a one-piece lens due to its size which is considerably smaller in diameter than the sulcus.
In order to guard against instability of the lens and its subsequent complications, some strategies with single-piece lenses in the presence of posterior capsular ruptures have been devised and shared.
220.127.116.11 Placement of One-Piece Hydrophobic Lenses into the Capsular Bag
In the event of a linear break in the posterior capsule during cataract extraction, the authors have found from their experience that it may still be possible to implant the premium lens into the capsular bag. Our technique is as follows. Dispersive OVD is placed in the region of the capsular break to isolate and compartmentalize the vitreous posterior to the capsular bag. Cohesive OVD is placed into the capsular bag and anterior chamber. The lens is then implanted into the anterior chamber and allowed to open up fully. The haptics are then placed into the capsular bag (the authors have found microforceps to be especially helpful for this), so as to straddle the linear break in the posterior capsule. The cohesive OVD is then removed using low parameters; the dispersive OVD may be left in place. The anterior chamber is reformed with BSS. Finally, the lens is located in its proper alignment (of importance for multifocal and toric lenses) and is tested to ensure that it is stable within the capsular bag.
The authors have experience in a small number of cases of one-piece hydrophobic lenses placed into the capsular bag in the presence of a linear posterior capsular tear followed for a number of years without complication; recently Kevin Miller MD has also shared his experience with a similar case which was stable after 1 year (personal communication).
(A video, entitled “One Piece IOL In the Bag Placement in Presence of PC Tear” is provided by the authors, and is included in the DVD which accompanies this book)
Similarly, accommodating lenses can also be placed in the presence of linear tears limited to the central portion of the posterior capsule and not involving the equator.
18.104.22.168 Reverse-Optic Capture of One-Piece Hydrophobic Lenses
Single-piece lens placement into the capsular bag in cases of intact central anterior capsulorhexis has also been reported. In these cases, the optic was captured by the rhexis (reverse-optic capture), and the haptics were left in the capsular bag. Up to 4 years, follow-up without complication was reported .
Reverse-optic capture of a toric single-piece lens has been reported to result in continued stable outcomes at 2 years postoperative. Although in this case there was no posterior capsular tear, this experience does confirm that reverse-optic capture results in stability .
22.214.171.124 Optic Capture by Anterior Capsulorhexis of Sulcus Placement of One-Piece Lenses
Reverse-optic capture raises some concerns for the authors of this chapter. Ollerton et al. have recently reported iris complications in cases of lenses with square anterior edged optics being placed in the sulcus . Although the report was in regard to three-piece lenses, is it still worrying that the same may occur with one-piece lenses in cases of reverse-optic capture.
For this reason, the authors of this chapter have chosen to place one-piece hydrophobic lenses in the sulcus and to capture the optic posterior to the anterior capsulorhexis when faced with the situation of posterior capsular defect and an intact anterior capsulorhexis. Three-year follow-up in only a handful of cases has been observed by the authors; no complications have occurred (A video, entitled “One Piece IOL In Sulcus, Optic Capture By Ant. Capsulorhexis” is included in the DVD which accompanies this book).
126.96.36.199 Scleral Fixation
Scleral fixation of one-piece lenses using the Hoffman pocket technique has been reported in two cases of toric lenses, with 30-month follow-up without complication or instability [36, 37]. In these cases, the haptic of the lens was surrounded by sutures which were externalized in the Hoffman pockets, similar to the technique described for three-piece lenses, with a comparable safe, stable outcome.
17.3 Convert to Sulcus or Iris Clip Premium Lenses
Currently, no specially designed pseudophakic premium lenses for sulcus placement or fixation to the iris are available.
The Rayner Sulcoflex series of hydrophilic acrylic lenses (Rayner.com) are designed for sulcus placement, but as supplemental or piggyback lenses. They have a 14 mm diameter and a 6.5 mm optic with a round edge, and a 10° posterior haptic angulation. These are produced as aspheric (653 L), multifocal (653 F), toric (653 T) and multifocal toric (653 Z) designs. The available range of spherical powers is −10 to +10 D for the aspheric, and −7.00 to +7.00 for the toric and multifocal models (although some are of special order) and cylinder powers of up to 6 D. With regard to safety, Kahraman has reported no iris chafe with Sulcoflex lenses; a range of 243–624 μm of clearance of the optic to the iris in a series of patients was found . Although designed to be used as supplementary or piggyback lenses in pseudophakic patients with presbyopia or ametropia, it is conceivable that these lenses could be employed for sulcus placement in patients with suitable power range calculations.