Trans-optic Suture Fixation of Subluxated Intraocular Lenses

Purpose To report a technique for xating posterior chamber intraocular lenses (PCIOLs) to the sclera by passing sutures through the lens material Methods Cases in which PCIOLs were xated to the sclera using trans-optic sutures were included in this series. Intra and post-operative complications were recorded, and lens position was assessed using slit lamp examination. Results Fourteen cases were included in this series. In 9 cases the procedure was performed using 9-0 polypropylene in pseudophakic eyes to correct subluxation, centration, tilt or to replace a broken haptic. In 5 cases this technique was used for primary PCIOL xation using a anged 6-0 polypropylene suture in aphakic eyes. In all cases the lenses remained centered and stable at the end of follow up, and no post-operative complications occurred.


Introduction
Scleral xation of posterior chamber intraocular lenses (IOLs) is a practical surgical strategy for IOL implantation in the absence of adequate zonular or capsular support. Various methods for scleral xation have been described over the past 30 years [1][2][3] though it has seen a recent surge in popularity with the introduction of the sutureless techniques of Scharioth [4], Agarwal [5] and Yamane [6]. In some cases, however, standard scleral xation techniques may not provide a satisfactory solution. For example, in cases where one haptic is broken or detached and cannot be used for xation. Another example is cases in which the haptics of the IOL are made of a soft pliable material as in hydrophilic acrylic IOLs, and with a tapered haptic design; these are often not suitable for suture xation due to the risk of slippage. A third example is a case of decentered or tilted IOL [7], which needs to be positioned in a direction different from the axis of the haptics. Domingues et al. described a technique for scleral xation using a 10-0 nylon suture which is passed through the optic and termed it "Cupid xation" [8]. To the best of our understanding, the cases in their series were of in-the-bag subluxated IOLs. We present the use of transoptic suturing in various other clinical scenarios, as well as modi cations to this technique including a technique for optic-based scleral xation to correct aphakia. Importantly we present techniques using either 9-0 polypropylene with scleral knots or a anged 6-0 polypropylene. Both these techniques can be applied to any material of foldable IOLs (Figure 1).

Surgical technique -anged polypropylene
Trans-optic IOL xation can be performed using 6-0 polypropylene, a suture recently popularized for transscleral xation [9][10][11]. This can be done in two ways by either using the original curved needle of the 6-0 prolene suture in aphakia, or by threading the naked suture through the lumen of a 30G needle in pseudophakia with subluxation.

Primary xation -aphakia
The IOL is prepared while still outside of the eye. The curved 3/8 needle is inserted through the lens material of the IOL haptic, IOL optic or at the optic-haptic junction. Using diathermy, a ange is created preferably on the posterior surface of the IOL to eliminate cha ng of the iris tissue. The sutures are then inserted through the main corneal incision to exit at the predetermined location at 1-2 mm posterior to the limbus using a 30G needle as a guide. The IOL is inserted only after the prolene sutures are in place thus no suture manipulations are required after implantation and lens positioning is safe and comfortable.
The sutures are then shortened in a stepwise fashion, and external anges are formed facilitating nal adjustments in IOL position. Steps of this technique are presented in gure 2.

Secondary xation -pseudophakia
The following is performed in cases of subluxated IOLs ( gure 3). A 30G docking needle is inserted through a paracentesis (PA), and then passed through the optic material using a second instrument for counter traction as described above. Intraocular forceps can also be used to stabilize the IOL. The 6-0 polypropylene suture is inserted through a paracentesis 180 degrees away (PB) and docked into the needle. The needle and suture are removed from the eye, and a ange is created using diathermy. The anged edge of the suture is re-entered into the eye (PA) with the ange positioned posterior to the IOL. A docking needle is passed 2mm from the limbus (on the side of the ange), and the un-anged edge of the suture is re-entered into the eye (PB), docked into the needle, and externalized. The suture is shortened to facilitate good IOL centration, and a ange is created.
Surgical technique -9-0 polypropylene A 10-0 Polypropylene suture can also be used for this technique, though 9-0 is preferred by the authors for its superior strength. A conjunctival peritomy is performed at the site of planned suture passage. A 9-0 polypropylene suture on a straight needle (MANI, Utsunomiya, Japan) is passed 2 mm posterior to the limbus and advanced until visualized through the pupil. The suture is then passed through the peripheral portion of the optic material or at the optic-haptic junction. A second instrument, typically a lens hook or manipulator, is needed at this point to tilt the IOL at an angle to facilitate suture passage, as well as for providing counterforce against the movement of the needle. The suture needle is then docked inside a 27G or 30G needle inserted through a paracentesis 180 degrees away, externalized from the anterior chamber and then re-inserted through the same paracentesis taking care to avoid creating a false passage through corneal tissue. The suture is then docked into a 27G or 30G needle placed approximately 2 mm away, on a horizontal plane, from the primary suture entry point. Alternatively, the suture can be passed again through the optic material near the original passage (double passage through the optic), thus creating a wider area of contact. Once outside of the eye, the suture is tied, buried in the sclera, and the peritomy is closed. The main steps of the procedure our shown in gure 4 and the video.

Results
Nine pseudophakic eyes of 9 patients underwent trans-optic scleral xation using a 9-0 polypropylene suture (Table 1) and 5 aphakic eyes of 5 patients underwent trans-optic scleral xation using a anged 6-0 polypropylene suture ( Table 2). In one case both techniques were used in a single eye -primary xation using a 6-0 polypropylene suture and correction of IOL tilt by a 9-0 polypropylene suture (case number 5 in table 2).

Pseudophakic cases
Four of the lenses were hydrophobic acrylic, 4 were hydrophilic acrylic and 1 was a silicone plate haptic ( Figure 2). The function of the trans-optic suture was to replace a detached haptic in 4 of the cases, to rexate an unstable subluxated IOL in four cases, to re-center a stable but decentered IOL in 1 case and to correct severe IOL tilt in 1 case. In the 4 cases in which the subluxated IOL was re-xated to the sclera using trans-optic sutures the IOLs were hydrophilic and had a tapered haptic (B-Lens, Hanita, Israel).
These 4 cases required entry at 2 different locations on the haptic -180 degrees from each other in 3 cases, and 90 degrees from each other in one case. In the 4 cases in which a trans-optic suture was used to replace a detached haptic, entry at 1 site on the optic su ced. In one of these, a double pass through the optic was used. In the case of the signi cantly decentered plate haptic silicone lens, a single transoptic suture placed perpendicular to the axis of the lens adequately centered the lens. In one case signi cant IOL tilt was evident after implantation of a 1-piece acrylic using 6-0 polypropylene anged scleral xation following intracapsular cataract extraction (ICCE). A single trans-optic suture was inserted perpendicular to the axis of xation to resolve the tilt.

Aphakic cases
Primary scleral xation of posterior chamber IOLs was performed in 5 cases. Four of these cases were following ICCE, and the fth case was after removal of an opaci ed IOL that dislocated into the vitreous.
The IOLs in all cases remained stable and centered until their last follow up examinations. The xated lens was a 1-piece hydrophobic acrylic in 4 of the 5 cases, and a 1-piece hydrophilic acrylic in one case. In the 5 th case the two-point xation by 6-0 polypropylene suture resulted in signi cant IOL tilt, which was corrected by a single 9-0 polypropylene suture perpendicular to the axis of the haptics ( gure 5).

Discussion
Scleral xation of IOLs is a popular and well-established strategy used in cases of inadequate capsular support. Trans-optic suture xation can be used to replace standard scleral xation techniques in certain cases, and to augment them in others. At the time we performed the presented cases we were not aware of the previous publication by Domingues et al, however he was apparently the rst to report the "Cupid xation" and should be credited for pioneering this technique.
In the original description by Domingues et al. 8 , the reported subluxated IOLs were apparently in-the-bag.
In our experience in such cases, looping a suture around the bag-haptic complex is less challenging and far less traumatic than creating a trans-optic suture. Passing a needle through the lens optic requires tilting of the lens, often turning a limited zonular dehiscence or weakness into a complete loss of zonular support. In contrast, three scenarios seem to bene t speci cally from the trans-optic approach. The rst is in the case of a subluxated 1-piece acrylic IOL with tapered haptics which are located outside of the capsular bag. In these cases, the approach of looping a suture around the haptic may not su ce as the haptic may slip out of the loop. This risk seems to be related to the soft and pliable hydrophilic material of the haptics. The second scenario is the missing haptic, mostly seen with haptic detachment in 3-piece lenses, or a torn haptic of a 1-piece lens. Two of our cases occurred after performing Yamane's xation of 3-piece hydrophobic IOLs. The haptics detached from the optics, likely during IOL maneuvers, causing IOL subluxation. In these cases, a single trans-optic suture can be used to replace the missing haptic and stabilize the IOL. The polypropylene suture functions as a "pseudo-haptic". The nal scenario is adjustment of lens position in cases of residual decentration or tilt. In one case in this series a trans-optic suture was used to center an IOL which was severely decentered, though not tilted, whereas in another case a trans-optic suture was used to resolve signi cant IOL tilt in an otherwise well centered lens. In cases of aphakia with no capsule support, trans-optic suturing is a valuable option as well. This is done by fashioning pseudo-haptics using 5-0 or 6-0 polypropylene sutures and the creation of anges to avoid scleral aps and knots.
In addition to demonstrating the utility of this technique in a variety of different clinical settings and with different IOL materials, this series also shows the variety of ways to use trans-optic suturing. In 5 of the 9 pseudophakic cases the suture was used to anchor the IOL to the sclera at one location, and in the remaining 4 cases 2 sutures were used to anchor the IOL in 2 different locations. In 3 cases a double pass of the suture was performed through the optic. This provides a wider area of contact for the suture and can potentially aid in the stability of the lens.
Special care should be practiced not to stretch the suture after passing through the soft lens material and to avoid excessive IOL manipulations. In a case not included in this series, manipulations on the lens and excessive stretch caused the suture to "cheese wire" through the optic. It is advised to carefully observe the location of the suture passage through the lens at the end of surgery to con rm stability.
In conclusion, trans-optic IOL suturing is a useful technique which can be utilized in all commonly used foldable IOLs and in a variety of different clinical situations.

Declarations
Ethics approval: This is case series, no approval required.
Consent for Publication: A consent to publish these cases, ndings and images were gathered from the patients. All the patients were adults.
Availability of data and material: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
Competing interests: The authors declares that they have no competing interests.
Funding: The authors do not have any sources of support, including sponsorship or sources of material not available commercially.
10. Assia EI, Wong JXH. Adjustable 6-0 polypropylene anged technique for intrascleral lens xation.  Trans-optic xation of a PC-IOL using 6-0 polypropylene ange technique a. Subluxated hyper-mature rock-hard cataract was removed through a scleral tunnel (ICCE). b. The 6-0 polypropylene suture is passed at the optic-haptic junction and a ange is created to create a pseudo-haptic. c. The polypropylene sutures are externalized using 27G needles on opposite sides. IOL implantation is very safe as the lens is inserted only after the sutures are externalized. d. One-month post operatively the IOL is stable and central. The anges are well covered by the conjunctiva.

Figure 3
Flange xation using 6-0 polypropylene. a. Subluxated extracapsular acrylic intraocular lens. b. A 30G needle is inserted through a paracentesis and passed through the peripheral optic. The 6-0 prolene is threaded through it, and the needle externalized. c. A ange is created so that it will be positioned on the posterior aspect of the optic. d. Good lens centration with the ange visible at its nal position.

Figure 4
Subluxated hydrophilic IOL and total aniridia in a 92-year-old following penetrating trauma. a. Two months after primary closure of corneo -scleral wound the IOL is tilted, hanging on a brotic adhesion between the IOL haptic and the cornea. b. A 9-0 polypropylene suture is passed through the lens material to xate the IOL to the scleral wall. Adhesions were released and the contracted capsule was removed using a vitrectome. c. Trans-optic scleral xation of the opposite haptic d. The IOL is stable and central. The patient refused surgical correction of the aniridia. Trans-optic xation to correct IOL tilt a. Toric PC-IOL xated by two trans-optic 6-0 prolene sutures. The IOL is signi cantly tilted relative to the iris plain. b. A third trans-optic polypropylene 9-0 suture is inserted perpendicular to the IOL axis to compensate for the lens tilt. c. Three-point xation of the IOL. The lens is central, stable, parallel to the iris plain and at the correct toric axis.