IOL Fixation in the Absence of Capsular Support

Is There a Best Buy? Industry experts weigh in on today’s top procedures. Dr Soosan Jacob MS, FRCS, DNB reports

The Main Symposium on “IOL Fixation in the Absence of Capsular Support” at the Winter ESCRS conference— chaired by Professor Jorge L Alió and Professor David J Spalton—was an enlightening one with well-known speakers giving valuable insights into their procedure of choice.

ANTERIOR CHAMBER IOLS Dr Richard Packard began by discussing the reasons behind the checkered past of anterior chamber IOLs (ACIOLs). This type of lens appeared in the early 1950s. It was popular because placement was easy, non-traumatic, and stable and its power calculations were similar to those for contact lenses—an advantage in the absence of ultrasound and other technologies.

However, all early ACIOL models failed. Nordeholm reported in 1975 that Barraquer had to remove 250 of 493 of these IOLs. In 1979, Drews examined half of these explanted IOLs and found poor manufacturing and rough edges, resulting in endothelial compromise, UGH syndrome, iris bombe, iris tuck, etc.

Rigidity was also thought a contributor to the poor performance, resulting in many flexible loop designs, almost all failing except for the Kelman Quadriflex. This was further modified as Kelman Multiflex by incorporating Peter Choyce’s findings on correct sizing of footplates and plano-convex optics, serving as the standard since 1980.

Three studies (Bellucci et al, 1996; Everiklioglu et al, 2003; Donaldson et al, 2005) comparing ACIOLs with sutured PCIOLs found no significant differences in outcome. For ACIOLs, Dr Packard said there was a clear need for proper education regarding accurate measurement of white-to-white (WTW) and incision size.

He also noted the importance of proper IOL sizing (WTW+1 mm), the need for an IOL bank with three sizes for each IOL power, and the need to recalculate for correct A-constant (115.3). WTW can be measured on a table with standard callipers, Stahl caliper, Kelman dipstick, or intraoperative anterior segment OCT. Other essentials include using Miochol®-E to constrict the pupil, a Sheets lens glide to assist implantation, and cohesive viscoelastic.

He advised using a gonio lens to check proper haptic positioning and the absence of iris distortion. PCIOL placement in the anterior chamber should be strictly avoided because of the high incidence of endothelial cell loss.

Dr Packard said the current design has stood the test of time, with results comparing favourably with scleral fixation IOLs provided basic rules of measurement and insertion are applied. It offers a simple, straightforward, and quick implantation technique in a compromised eye, thus not prolonging an already long procedure.

IRIS-CLIP IOLS Dutch innovator Jan Worst developed the iris clip IOL (ICIOL) in the early 1970s. That lens comes in two models: aphakic, a non-foldable, rigid, single-piece PMMA requiring a 5.5–6.0 mm incision that needs suturing; and phakic, the modern version being three-piece with foldable acrylic optic and PMMA haptics that hold on to iris tissue.

The aphakic model can be used for anterior chamber (AC-ICIOL) or retropupillary (RP-ICIOL) enclavation. Professor Sorcha Ní Dhubhghaill offered her perspective on the ICIOL she preferred as her first choice if bag or sulcus placement were not possible. Poor candidates for the ICIOL include those with insufficient iris tissue, uveitis, and ischaemic vitreoretinopathies (diabetic retinopathy or vascular occlusions), as the iris may also be involved, she noted.

An interesting report by Sarioglu [et al] used two ICIOLs for both anterior and posterior enclavation in the same eye for a case of nanophthalmos. At Prof Ní Dhubhghaill’s hospital, among 492 IOL explantations, 28% had received ICIOL, with 5% AC-ICIOLs and 23% RP-ICIOLs. AC-ICIOL and RP-ICIOL seemed to have equivalent visual outcomes, although RP-ICIOLs performed slightly better with some IOP reduction and lesser CME. Data showed endothelial loss to be the same for both positions as AC-ICIOLs are at a more posterior plane in aphakic eyes than in phakic eyes.

Though enclavation is easier with RP-ICIOL, it needs additional dexterity and vitrectomy to avoid vitreous incarceration while enclavating. Haigis, Holladay 1, and SRK/T formulae work well, but it should be remembered A-constant is lower for AC-ICIOL and higher for RP-ICIOL, Prof Ní Dhubhghaill cautioned.

Complications include pupillary peaking and ovalization, IOL drop with unstable RP-ICIOLs, and endothelial decompensation with AC-ICIOLs. Prof Ní Dhubhghaill concluded that ICIOLs were reliable, stable, and technically simple with no major issues with tilt. Disadvantages include large incisions, hard material, scleral tunnels, incisional sutures, difficulty in enclavation (especially in post-vitrectomised eyes), and ordering these IOLs beforehand.

Dr Packard said the current design has stood the test of time, with results comparing favourably with scleral fixation IOLs provided basic rules of measurement and insertion are applied.

SCLERAL FIXATED IOLS Several speakers discussed different techniques of scleral fixation.

Sutured SFIOL:

Dr Mayank Nanavaty demonstrated the sutured SFIOL technique by showing intravitreal triamcinolone acetonide-assisted anterior vitrectomy, followed by scleral IOL suturing and 9-0 Prolene suture anchoring under partial-thickness scleral flaps. He also showed variations such as sclerally sutured aniridia IOLs and combined surgery with customised DSAEK lenticule.

Intrascleral haptic fixation (ISHF):

Advantages of intrascleral haptic fixation include a sutureless standardised technique, minimal contraindications, standard PCIOL, minimal uveal contact, easy centration, and indepen-

dence from angle and iris. Dr Gabor Scharioth gave important tips such as making symmetrical sclerotomies 180 degrees apart and 1.5–2.0 mm post-limbal, using AC or pars-plana infusion for globe stabilisation, performing vitrectomy and capsulectomy, using handshake technique, and creating a peripheral iridectomy in eyes with floppy or sticky iris. Dr Scharioth emphasised the importance of proper instrumentation (e.g., Scharioth forceps, DORC), proper IOLs (e.g., AR40e Sensar® IOL), exchanging instead of refixing a dislocated and damaged IOL, and suturing sclerotomies in case of leaks. He also reported on his use of single-piece AcrySof® platform IOLs and even the PanOptix® IOL for ISHF when powers more than 30 dioptres or multifocals were desired—but found that after two years, nearly 50% of cases showed scleral atrophy with extrusion of haptic tip into the subconjunctival space. Though revision with haptic trimming and scleral suturing over haptic showed good intermediate results, he concluded this was not the ideal technique yet.

Flanged IOL—Yamane Technique:

The Yamane technique has advantages of a minimally invasive transconjunctival approach, sutureless surgery, weathertightness, and the ability to perform under topical anaesthesia with some subconjunctival infiltration near tunnels. Dr Vladimir Pfeifer said the biggest challenge was docking, and hence many variations have been introduced. He demonstrated his own technique that included marking entry points 2.2 mm behind limbus, limbus-parallel tunnels to avoid lens tilt, 45-degree bend for the first needle, and 80–90 degrees for the second needle. He mounted the thin wall 30 g needles on a syringe for better control while docking and then dismounting using pean forceps, resting and stabilising the first needle on the iris after docking to prevent needle tip proximity to retina. Docking the second haptic is performed through the main 3 mm incision using Eckardt forceps again. Both haptics are externalised, pulling needles simultaneously out of tunnels. Flanges are performed and partially buried into the scleral tunnels under conjunctiva. Dr Pfeifer said advantages include the ability to perform even with small pupils, adding surgeons need to take care to avoid haptic damage and consequent tilt. His tip is to hold the Eckardt forceps in the same way as a fencing foil.

Carlevale IOL:

The Carlevale IOL is a single-piece foldable IOL specially designed for sutureless intrascleral fixation. It has a closed haptic design acting like a spring and damper to adjust to different sulcus widths and a T-shaped terminal end to haptics for anchoring under scleral flaps. Dr Matteo Forlini emphasised that contraindications for scleral fixation included connective tissue disorders and scleromalacia. UBM evaluation in a study by Mularoni [et al] showed a low incidence of horizontal or vertical optic plate tilt. ASOCT showed secure intrascleral haptic fixation. The study also described a special case where surgeons used the closed-loop haptic design to confine silicone oil to the posterior segment. Advantages include easy and fast implantation, foldable and “elastic” IOL, nature, and a minimal learning curve. Dr Forlini advised caution to avoid excessive pulling, which could break or rupture the haptic or the T-plug. INSIGHTS FROM THE EXPERTS The informative session included discussion breaks where session chairs Professor David J Spalton and Professor Jorge L Alió gave valuable insights. Prof Spalton summarised that most fixation types work well if surgeons follow the proper technique. Since all techniques have a learning curve, surgeons with no prior experience may find it daunting to suddenly implant them in complex and complicated eyes in an atmosphere of surgical stress. Training, therefore, goes a long way in helping handle these situations, but if in doubt, it can be better to leave the eye aphakic and come back to do the implant as a planned secondary procedure in a more relaxed situation for both the surgeon and the patient.

Prof Spalton noted vitrectomy skills, a bimanual approach, and specialised instruments were necessary for most iris and scleral fixation techniques whereas iris clip IOLs had a lower learning curve.

Prof Alió discussed the Gore-Tex suture’s disadvantages of being thick and ropy, forming chunky, difficult-to-bury knots as well as the need to obtain them from the cardiac theatre. He said the Alcon MA60 IOL was his first choice for sulcus placement, iris suture, scleral suture, and even ISHF, but it ran a risk of the embedded haptic coming loose. His second choice was the Zeiss CT Lucia three-piece IOL. Lastly, he discussed the advantages of scleral flaps and tissue glue in preventing postoperative hypotony. The session concluded by stressing the need for stratification of techniques based on ease of performance and surgeon experience.

At the end of the symposium, the audience voted on what they thought was the “best buy” technique. All techniques had their supporters, but iris clip IOLs came out as the winner.

Since all techniques have a learning curve, surgeons with no prior experience may find it daunting to suddenly implant them in complex and complicated eyes in an atmosphere of surgical stress.

Dr Soosan Jacob is Director and Chief of Dr Agarwal’s Refractive and Cornea Foundation at Dr Agarwal’s Eye Hospital, Chennai, India. dr_soosanj@hotmail.com. Richard B Packard MD, DO, FRCS, FRCOphth: eyequack@vossnet.co.uk Sorcha Ní Dhubhghaill MD, PhD, MRCS(Ophth), FEBO: nidhubhs@gmail.com Gabor Scharioth MD, PhD: gabor.scharioth@augenzentrum.org Vladimir Pfeifer MD: oefpv@icloud.com Matteo Forlini MD: matteoforlini@gmail.com David Spalton FRCS, FRCP, FRCOphth: profspalton@gmail.com Mayank A Nanavaty MBBS, DO, FRCOphth, PhD: mayank_ nanavaty@hotmail.com Jorge Alió MD, PhD, FEBOphth: jlalio@vissum.com