20.1 Introduction

Gabor Scharioth et al first reported and performed intrascleral haptic fixation of an intraocular lens (IOL) ¹ followed by Agarwal et al who suggested making of scleral flaps and tucking of the haptics intrasclerally beneath these flaps. ² Glue-assisted intrascleral haptic fixation of an intraocular lens (glued IOL) is one of the established modes of performing intrascleral haptic fixation of an IOL. Since the technique was first introduced in 2007, it has undergone various changes and modifications by various surgeons so as to suit to their requirements and capabilities in an effort to enhance the visual potential and ease down the surgical procedure. ^{3 , 4 , 5 , 6} Many surgeons have also reported performing the glued IOL procedure with an exception to replace the glue application at the end of the surgical procedure with sutures in an attempt to cut down the cost and also to comply with the issue of nonavailability of tissue glue in some parts of the world.

20.2 Preoperative Assessment

The preoperative assessment comprises the following aspects:

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  Visual acuity: The measurement of visual acuity should always be performed as it gives an idea of the possible visual correction that can be achieved in the postoperative period. The pinhole vision correction should also be assessed along with the best corrected visual acuity.

  
  
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  Optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) analysis: OCT helps to rule out the presence of any subtle retinal/macular changes that may pre-exist following complicated cataract surgery. UBM serves as a noninvasive tool and is of tremendous value, for evaluating posterior segment disorders without the need for dilation of pupil.

  
  
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  Secondary glaucoma: Intraocular pressure (IOP) monitoring is of utmost importance as pre-existing secondary glaucoma can be an associated component due to previous surgical interventions and inflammation. Presence of vitreous in anterior chamber (AC) leads to marked increase in IOP. In addition to this in cases associated with trauma, often angle recession is seen that needs to be tackled and antiglaucoma surgery is necessary to control the IOP rise. IOP-lowering medications along with intravenous infusion of mannitol prior to secondary IOL fixation help to safely intervene and perform the surgical procedure. The patient should be screened for secondary glaucoma.

  
  
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  Specular microscopy: An eventful cataract surgery leads to corneal decompensation that may result from depletion of the corneal endothelial cells. In severely decompensated corneas, it is often necessary to perform endothelial keratoplasty (EK) with glued IOL procedure.

  
  
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  Measurement of white-to-white (WTW) diameter: This is extremely important as WTW diameter gives a brief idea of the site to choose for scleral flap making during the procedure. Although WTW can be measured intraoperatively too, doing so in the preoperative period can help the surgeon chose the surgical positioning of the flaps as well as the sitting position of the surgeon well in advance.

20.3 Surgical Technique

The surgical technique of glued IOL comprises the essential steps mentioned below (▶Video 20.1, ▶Video 20.2, and ▶Video 20.3):

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  Scleral flap making: The initial step comprises 180° axis marking. Two partial-thickness scleral flaps approximately 2.5 by 2.5 mm are made around the marks that are exactly 180° opposite to each other (▶Fig. 20.1a, b). Too large and too small flaps should be avoided as difficulties are encountered during the surgical procedure. If the flaps are too large, the haptic has to traverse extra distance before it can be tucked into the scleral pocket. Therefore, in large eyes where the haptic externalization is considerably less, inadvertently making large flaps allows the very little portion of haptic to be tucked intrasclerally that can eventually lead to subluxation of the IOL.

  
  

  Too small flaps lead to incomplete coverage of the haptic and expose it to the conjunctival tissue. This can lead to endophthalmitis through the sclerotomy site that may pave way for organisms intraocularly.

  
  
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  Fluid infusion: The surgery should always be performed under fluid infusion. An anterior chamber maintainer (ACM), a pars plana trocar, or a trocar ACM ⁷ can be employed for the same (▶Fig. 20.1c, d).

  
  
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  Sclerotomy: Sclerotomy is made beneath the scleral flaps with a 22-G needle at a distance of 0.5 to 1 mm from limbus and the needle is directed obliquely into the midvitreous cavity (▶Fig. 20.1e).

  
  
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  Vitrectomy: A 23-G vitrectomy cutter is introduced from the sclerotomy site (▶Fig. 20.1f) and thorough vitrectomy is performed into the retropupillary zone and AC to cut down all the vitreous strands. A high cutter rate with moderate vacuum suffices the need well. Triamcinolone staining can be done to enhance the visualization of the vitreous.

  
  
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  Haptic externalization: A corneal tunnel incision is made and a three-piece foldable IOL is loaded. The tip of the leading haptic is made to slightly protrude from the cartridge by rotating the injector. This facilitates grasping the tip of the haptic while the IOL is being injected. The end-opening glued IOL forceps is introduced from the left sclerotomy site and the tip of the leading haptic is grasped (▶Fig. 20.2a). The IOL is slowly unfolded inside the AC and the cartridge is withdrawn a bit so that the trailing haptic lies at the corneal incision. The tip of the leading haptic is then pulled and externalized (▶Fig. 20.2b). The trailing haptic is then held with end-opening glued IOL forceps and is flexed inside the AC (▶Fig. 20.2c); meanwhile, the assistant holds the leading haptic and prevents it from slipping inside the AC. A glued IOL forceps is introduced from the side port incision and the surgeon then transfers the trailing haptic from right hand to left hand (▶Fig. 20.2d). The right-hand glued IOL forceps is withdrawn from the eye and it re-enters the eye from the right sclerotomy incision. The surgeon again transfers the trailing haptic from left hand to right hand (▶Fig. 20.2e). This transfer of haptics from one hand to another is known as handshake technique. ⁸ The tip of the trailing haptic is then grasped and it is pulled and externalized (▶Fig. 20.2f).

  
  
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  Intrascleral tuck: Scleral pockets are created with a 26-G needle along the edge of the base of flaps parallel to the sclerotomy site (▶Fig. 20.3a). The haptics are tucked into these scleral pockets with around 2 to 3 mm of haptic length being entrapped into the length of the pockets (▶Fig. 20.3b, c). Vitrectomy is again performed at the sclerotomy site to prevent any vitreous being incarcerated into the wound.

  
  
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  Fibrin glue-assisted flap sealing: The fluid infusion is stopped; fibrin glue is applied beneath the flaps and along the conjunctival peritomy site to seal it (▶Fig. 20.3d).

20.3.1 No-Assistant Technique (NAT)

NAT is a modified method of haptic externalization where the surgeon does not need an assistant to hold the leading haptic. ³ The technique works on the principle of direction of vector forces. Once the leading haptic is eternalized, the surgeon grasps the trailing haptic and flexes it more towards 6 o’clock position. At this juncture, the vector forces act in a way that the leading haptic is extruded more from the sclerotomy site and it does not need an assistant to hold the haptic as there is no tendency for the haptic to slip back inside the eye (▶Fig. 20.2). Meanwhile, the surgeon performs handshake technique for externalization of the trailing haptic (▶Video 20.4).

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