CASE SELECTION FOR INTRASCLERAL HAPTIC FIXATION
Priya Narang, MS and Ashvin Agarwal, MD
Transscleral fixation of an intraocular lens (IOL) can be performed with a sutured or a sutureless technique. Suture erosion and breakage are the main concerns for sutured transscleral fixation. In 1997, Maggi and Maggi performed the first sutureless transscleral fixation of a specially designed posterior chamber IOL (PCIOL).1 In 2006, Scharioth and Pavilidis conceived of and performed the first intrascleral haptic fixation of a 3-piece IOL,2 laying the foundation for all the techniques and currently performed procedures that have become widely adopted worldwide. Glue-assisted intrascleral fixation (glued IOL) was first described by Agarwal et al in 2007, where the sclerotomy was made beneath partial-thickness scleral flaps for haptic externalization followed by sealing of the flaps with fibrin glue.3 Various modifications have been introduced in glued IOL fixation since then that vary from modifications in haptic externalization to scleral flap making.4–7 In 2014, Yamane et al introduced 27-gauge needle-guided intrascleral haptic fixation, and in 2017, they introduced the flanged double-needle technique for sutureless, glueless intrascleral fixation of the IOL.8,9
Case Selection for Intrascleral Haptic Fixation
Intrascleral haptic fixation is one of the choices for secondary IOL fixation that allows the IOL to be placed securely close to the effective lens position of an intracapsular IOL in the posterior segment. The procedure can be performed in all eyes that have a deficient posterior capsule except in cases with scleromalacia and other scleral disorders where the sclera is effectively too thin to bury the haptics of the IOL. A 3-piece IOL is preferable and is recommended for intrascleral haptic fixation. The primary concern with a single-piece IOL is the difficulty incurred in externalizing haptics, as the haptics are not flexible and they tend to break easily. A foldable or nonfoldable 3-piece IOL can be employed in intrascleral haptic fixation, but of course a nonfoldable IOL has the disadvantage that it requires a larger incision to introduce the IOL.
Case Selection for Glued IOL
Apart from performing glued IOL (Figures 52-1 through 52-3) in cases with an absent posterior capsule, the technique can also be performed in combination with various surgical procedures in different scenarios.
CASES WITH LARGER WHITE-TO-WHITE DIAMETER
The “quintet” (Figure 52-4) comprises 5 different techniques that are performed in sequential order to optimize the results of glued IOL surgery.10 This is especially indicated in cases with greater white-to-white diameter, as these eyes’ greater size necessitates a special set of techniques due to the limitation imposed by the overall length of a 3-piece IOL.
The first technique that is employed is vertical glued fixation, wherein 2 partial-thickness scleral flaps are made at the 12 and 6 o’clock positions 180 degrees opposite to each other.11 The concept behind making vertical flaps is that the vertical diameter of the cornea is less than the horizontal diameter. Because the haptics have to cover a shorter distance for externalization, a greater amount of haptic can be tucked into the intrascleral pockets.
Figure 52-1. Illustration showing the glued IOL procedure (part 1). (A) Illustration of an eye with deficient capsules. (B) A 25-gauge trocar anterior chamber maintainer placed via the limbus in the inferotemporal region. (C) After marking the scleral flap positions, localized peritomy was performed. (D-F) Two partial-thickness lamellar scleral flaps 2 x 2 mm were fashioned 180 degrees apart using the crescent knife.
The second method that is employed is the introduction of an infusion with trocar anterior chamber maintainer that allows continuous maintenance of the globe without encroaching upon the surface of cornea, thereby leaving the entire working space in complicated surgeries at the disposal of the operating surgeon.12 The trocar anterior chamber maintainer is introduced about 0.5 mm away from the limbus in a biplanar fashion in a way that it enters the eye in front of the iris plane. Alternatively, an anterior chamber maintainer or a trocar infusion in the pars plana can also be employed.
The third technique that is adopted is performing a peripheral iridectomy at the proposed site of sclerotomy with the help of a vitrector set at 20 cuts/min and low vacuum settings.13 This step is performed because in large eyes it is advisable to make an anterior sclerotomy. While doing so, the peripheral iris tissue often gets disengaged from the iris root or hyphema may be encountered. To prevent this dragging of iris tissue while performing anterior sclerotomy, peripheral iridectomy is performed so that it ensures smooth passage of needle and forceps from the sclerotomy site without damaging the iris tissue, as it is already cut.
Figure 52-2. Illustration showing the glued IOL procedure (part 2). (A, B) Main port and side port made in the clear cornea. (C) Sclerotomy was made below the scleral flaps using the 22-gauge needle. (D) Injector loaded with a foldable 3-piece IOL was engaged in the wound while the glued IOL forceps passed via the sclerotomy to receive the leading haptic. The leading haptic was then held in the glued IOL forceps and externalized under the scleral flaps. (E) Using the handshake technique, the trailing haptic was received by the glued IOL forceps through the other sclerotomy and the haptic externalized. (F) Both haptics externalized below the flaps.
The fourth part of the quintet is anterior sclerotomy, which is performed at a distance of 0.5 mm away from the limbus beneath the scleral flaps.14 After this, the glued IOL procedure is performed, and both haptics are externalized and are tucked into the scleral pockets.
The fifth component is performing pupilloplasty because anterior sclerotomy could cause an anterior shift of the plane of the IOL, which can lead to optic capture.15 Pupilloplasty is therefore performed with the intention of narrowing down the pupil size to 5 mm so that it is less than the optic diameter, thereby negating any chances of optic capture.
CASES WITH SMALLER WHITE-TO-WHITE DIAMETER
No special difficulty is encountered in cases with a smaller white-to-white diameter. The surgeon only needs to cut the externalized haptics so that the required amount can be fixated into the scleral tunnels.
Figure 52-3. Illustration showing the glued IOL procedure (part 3). (A) Intrascleral Scharioth tunnels were made by a 26-gauge needle at the point of exit of both haptics. (B) Haptics were tucked into the scleral tunnel. (C) Fibrin glue was applied and the scleral flaps were apposed. (D) Corneal incisions were hydrated, and the conjunctival peritomy was closed with fibrin glue.
Figure 52-4. Quintet in glued IOL. (A) A case of mature cataract with 360 degrees zonular weakness, phacodonesis, and a large white-to-white diameter of 15 mm horizontally and 13 mm vertically. A large iridectomy from previous trabeculectomy surgery is seen with a narrow bridge of iris tissue that forms the pupil. Two partial-thickness scleral flaps are made at 12 and 6 o’clock positions (vertical glued IOL). (B) Infusion is introduced in the eye. (C) Peripheral iridectomy is performed with the vitrector at low cutting rate at the proposed site of anterior sclerotomy. (D) Anterior sclerotomy is performed with a 22-gauge needle beneath the scleral flaps and behind the peripheral iridectomy. (E) Both haptics of a 3-piece IOL are externalized. (F) Single-pass four-throw pupilloplasty is performed.
Glued IOL Combination Procedures in Cases With Residual Nuclear Fragments and Deficient Sulcus Support
GLUED IOL SCAFFOLD
Posterior capsular dehiscence in association with non-emulsified nuclear fragments and absent sulcus support is a challenging scenario for the anterior segment surgeon. Under such circumstances, the glued IOL scaffold technique helps to overcome all the issues, although it calls for definite surgical skill.16–18
Preplacement and prefixation of an IOL by the glued IOL scaffold method effectively compartmentalizes the anterior and posterior chamber, and the preplaced IOL acts as an artificial posterior capsule and allows safe emulsification of the nuclear fragments subsequently.
Following an intraoperative posterior capsule rupture, the surgery is temporary halted, and viscoelastic is injected from the side-port incision before the withdrawal of the phacoemulsification probe from the eye. As in a glued IOL surgery, 2 partial-thickness scleral flaps are made 180 degrees opposite to each other. Sclerotomy is done with a 20-gauge needle about 1.5 mm away from the limbus, beneath the scleral flaps. The nucleus/nuclear fragments are levitated and brought into the anterior chamber with the help of a posterior-assisted levitation (PAL) technique.19 Infusion is introduced into the eye with the help of either a trocar cannula or an anterior chamber maintainer, care being taken to direct the flow of fluid in a way that it does not dislodge the nuclear fragments into the vitreous cavity. A 23-gauge vitrectomy cutter introduced from the sclerotomy site and from the corneal tunnel incision allows thorough vitrectomy to be performed in the pupillary plane. A 3-piece foldable IOL is loaded and is injected beneath the nuclear fragments, and the tip of the leading haptic is grasped with glued IOL forceps. When the entire IOL has unfolded, the tip of the leading haptic is externalized. The trailing haptic is then flexed into the eye and a handshake technique is performed for its externalization. The externalized haptics are then tucked into the scleral pockets created with a 26-gauge needle.
Following the tucking of haptics, the pupil is narrowed down with the help of pilocarpine to prevent any accidental dislodgement of the nuclear fragment from around the edges of the IOL. The phacoemulsification probe is then introduced, and the nuclear fragments are emulsified. The corneal wound is secured with a 10-0 suture, stromal hydration is performed to seal all the corneal wounds, and air is injected into the anterior chamber. Fibrin glue is applied beneath the scleral flaps and along the conjunctival peritomy incision.
This technique has found its application in other scenarios such as lens subluxation and Soemmering ring removal with a deficient posterior capsule.
GLUED IOL SCAFFOLD FOR TRAUMATIC SUBLUXATED LENS
In cases of traumatic subluxated lens, PAL is performed initially and the entire nucleus is levitated into the anterior chamber and is then made to rest on the anterior surface of the iris. Glued IOL scaffold is eventually performed and the entire nucleus is subsequently emulsified (Figures 52-5 and 52-6).
GLUED IOL SCAFFOLD FOR SOEMMERING RING WITH ASSOCIATED POSTERIOR CAPSULE RUPTURE
Various techniques have been described in the peer-reviewed literature explaining the procedure to manage Soemmering ring and subsequent IOL implantation. It is very tricky to handle Soemmering ring when it is associated with a posterior capsule rupture. Glued IOL scaffold can be implemented in such a scenario (Figures 52-7 through 52-9).
Soemmering rings are usually present around the peripheral edges of the pupillary margin. Vitrectomy is performed around the margins of Soemmering ring, taking care not to disrupt the Soemmering material. A 3-piece foldable IOL is introduced, and the glued IOL procedure is performed.
Preplacement of an IOL by glued IOL scaffold helps to form a base for the Soemmering ring. After vitrectomy is performed around the periphery of the Soemmering ring to release all the vitreous strands and adhesions, iris hooks are employed (if needed) to visualize the Soemmering ring clearly. The ring is then dislodged with a dialer and is brought into the center of the pupil. In cases of a widely dilated pupil, the pupil is constricted with intracameral pilocarpine to prevent any inadvertent loss of Soemmering ring material from around the peripheral edges of the IOL into the vitreous cavity. In cases where iris hooks were employed for adequate visualization, the iris hooks are removed for the same reason. Phacoemulsification is then performed, and the Soemmering ring material is eventually emulsified. The scleral flaps are then sealed with fibrin glue, and the corneal wound is secured with 10-0 suture.
ROLE OF POSTERIOR-ASSISTED LEVITATION IN GLUED IOL SCAFFOLD
The PAL technique allows levitation of the nucleus/nuclear fragments from the anterior vitreous into the anterior chamber. This procedure can be done with the assistance of a rod/blunt spatula or also with the help of viscoelastic that forms a base below the nuclear fragments and prevents them from further dislodgement into the vitreous cavity.
To perform PAL, a sclerotomy wound is created with the help of either a microvitreoretinal blade/trocar cannula (depending on the surgeon’s preference) about 3.0 to 3.5 mm behind the limbus. The blade is directed obliquely toward the midvitreous cavity. A blunt rod or spatula is inserted from the sclerotomy site, and the nucleus/nuclear fragment is supported at its base and is then levitated into the anterior chamber. It is often safe to place the levitated fragments onto the anterior surface of the iris along the anterior chamber angle so that they do not slip back into the vitreous cavity. Some surgeons prefer using viscoelastic for nucleus levitation, although the use of viscoelastic in the vitreous cavity should be curtailed as retained viscoelastic can often lead to inflammation.
Figure 52-5. Surgical steps of glued IOL scaffold procedure for traumatic subluxated cataract (part 1). (A) Traumatic subluxation of the lens. (B) The surgeon sits temporally and 2 partial-thickness scleral flaps are made 180 degrees opposite to each other at 6 and 12 o’clock positions. (C) Sclerotomy done with a 20-gauge needle about 1.5 mm away from the limbus, beneath the scleral flaps. (D) The subluxated lens is lifted with the help of a rod (PAL) introduced from the sclerotomy site. The lens is lifted and is placed into the anterior chamber. Pilocarpine is being injected into the anterior chamber to constrict pupil. (E) Vitrectomy is performed beneath the lens to cut down all vitreous adhesions. (F) A 3-piece foldable IOL is loaded and is injected beneath the subluxated lens, and the leading haptic is externalized followed by the trailing haptic. Handshake technique being done for externalization of the trailing haptic beneath the lens.
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