Clinicians can choose between a variety of intraocular lenses (IOLs) when managing aphakic eyes.1 Most scleral-fixated IOL (SFIOL) techniques involve suturing or tucking the haptic of the IOL into specially designed scleral pockets.2 We present the results of our new SFIOL, the CM-T Flex IOL (Appasamy Associates, Pondicherry, India), which has a novel design. It avoids the need for haptic manipulation in the form of tucking into preformed tunnels or flanging them. The unique T-shaped haptics can be pulled out of the eye and left as such under a scleral flap. This provides for shorter learning curves and lesser tissue handling.
The CM-T Flex IOL is a foldable hydrophilic acrylic SFIOL with an overall length of 13.50 mm (Figure 1). This is a specially designed lens that has a semicircular haptic and an extended T-junction, ensuring that the haptic can be exteriorized through a 23-gauge sclerotomy. The high-tensile material prevents breakage of haptics. A vault of 10° is provided between the optic and the haptic. A semicircular loop is factored into the design of the IOL haptic to increase its stretchability.
The CM-T Flex intraocular lens.
Localized peritomies are made at the 3-o'clock and 9-o'clock positions, and partial-thickness scleral flaps of 3 mm × 3 mm hinged on the limbus are elevated. A 23-gauge needle is used to create sclerotomies 1.5 mm from the limbus at the center of this scleral bed. After vitrectomy, the CM-T Flex SFIOL is introduced into the eye through a clear corneal or sclero-corneal incision (See Video below). The leading haptic is grasped at the center of the T junction using a 23-gauge PraNiv T Flex intraocular forceps (Appasamy Associates, Pondicherry, India), a specially designed forceps with short and broad teeth to hold the hydrophilic material without cutting through. This forceps is introduced into the vitreous cavity from the sclerotomy at 3-o'clock and exteriorized as the IOL is being injected. Once outside the eye, the T-shaped haptic anchors the IOL to the sclera. Simultaneously, the trailing haptic is injected into the eye and allowed to rest on the iris. Thereafter, a stab incision through the cornea at 2-o'clock meridian is used to introduce a Nishi grasping forceps (Appasamy Associates, Pondicherry, India) that has a serrated pattern on its tip to allow for firm grasp during handshake. The T-shaped trailing haptic is then exteriorized through the sclerotomy at 9-o'clock with the PraNiv forceps. The pliable and high-tensile material used in manufacturing this IOL ensures that T-shaped haptics that have been exteriorized open out and hitch onto the scleral bed under the partial thickness flap, anchoring the SFIOL. In this manner, there is no regression of haptic into the vitreous cavity. The scleral flap and overlying conjunctiva are then glued or sutured back to their respective positions.
Nine eyes completed a 3-month follow-up (Table 1). Uncorrected visual acuity (UCVA) before SFIOL surgery was 1.22 ± 0.28 logMAR (range: 0.77 to 1.8). Axial length of eyes studied was 22.97 mm ± 0.75 mm (range: 21.68 mm to 23.69 mm), and power of the CM-T Flex IOL implanted was 22.32 diopters (D) ± 1.64 D (range: 20.00 D to 24.00 D). At 3 months after surgery, UCVA had improved to 0.32 ± 0.42 logMAR (range: 0 logMAR to 1.2 logMAR).
There was no IOL instability, decentration, haptic extrusion, or optic capture in any eye. At 3 months, one eye had cystoid macular edema that resolved with the use of topical prednisolone acetate and nepafenac drops.
In the management of aphakic eyes, many SFIOL techniques are in use.3–5 Although each of these has their own advantages and disadvantages, they all use a three-piece IOL. The cornerstone in achieving and maintaining surgical success with the aforementioned techniques is diligent handling of the prolene haptics of the three-piece IOL. For novice surgeons, tucking the haptics into preformed scleral tunnels or using a cautery to carefully create a bulb and push it back to an adequate depth in the sclera are challenges. In order to eliminate these difficulties, the CM-T Flex IOL was developed. The unique design provides for simple exteriorization and release.
Recently, Veronese et al. have described a new FIL SSF Carlevale IOL (Soleko, Latium, Italy) with similar design and reported their results in four eyes.6 This IOL has a similar appearance to the CM-T Flex IOL. However, on closer scrutiny, few pertinent differences can be discerned. The haptic of the Carlevale IOL is wider with extensions beyond the optic of the lens, which in itself appears to be hexagonal. The distance between the semicircular haptic and the horizontal limb of the T-shaped haptic appears to be shorter in their design. This may restrict the ease of haptic exteriorization in addition to causing inadvertent tissue damage internally as the wide haptic would lie in close proximity or about the uveal tissue. With regard to the surgical technique employed, Veronese et al. used a 25-gauge trocar cannula system at the 5-o'clock and 11-o'clock positions for haptic exteriorization. Therefore, at the conclusion of surgery, the T haptic lies under the conjunctiva. We use partial-thickness scleral flaps 180° away from each other over the sclerotomies that are used for haptic exteriorization. These sclerotomies are separate from the ones used for vitrectomy. By this method, we ensure that the relatively broader T haptic (when compared to prolene haptics of three-piece IOLs) is less prone for exposure.
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