Needle-assisted iris-claw lens implantation: A novel, simplified technique for aphakia without capsular support

Abstract

We introduce a novel, simplified surgical technique for iris-claw intraocular lens implantation in aphakia cases without adequate capsular support. The Needle Assisted Iris-claw Lens (NAIL) technique utilizes a 10-0 prolene straight needle as an internal guide and pivot during enclavation, thereby enhancing centration, precision, and ease of intraocular lens implantation. This method has been successfully employed in multiple patients, demonstrating promising short-term outcomes with improved centration and fewer complications. Overall, NAIL appears to be an efficient, safe, and reproducible alternative for iris-claw IOL implantation, with the potential to reduce intraoperative difficulty and postoperative complications such as ovalization.

Cataracts remain the leading cause of reversible blindness worldwide, with over 94 million diagnosed individuals and approximately 1 billion individuals suffering from moderate to severe visual impairment.[1] Although in-the-bag or sulcus intraocular lens (IOL) placement is ideal, alternative fixation strategies are required in the absence of adequate capsular support in the eye. These include scleral-fixated, iris-claw, or anterior chamber IOLs, each with unique risks and technical nuances.[2]

Although older closed-loop anterior chamber IOLs led to complications such as cystoid macular edema (CME), uveitis-glaucoma-hyphema syndrome, and corneal decompensation, modern open-loop ACIOLs have reduced such issues.[3] Iris fixation, especially the iris claw lens, has become a valuable, suture-less alternative, pioneered by Jan Worst in 1971. Rijneveld et al.[4] introduced the technique of retropupillary fixation of an iris-claw IOL in adults. This approach offers the benefit of positioning the ICIOL behind the iris, thereby preserving the corneal endothelium and reducing the risk of complications compared to scleral-fixated posterior chamber IOLs. The procedure demands precision and surgical expertise as successful enclavation largely depends on the surgeon’s skill. Additionally, it is often performed in conjunction with vitrectomy, necessitating proficiency in both anterior and posterior segment techniques. Surgical complexity, particularly during enucleation, remains a challenge.[5]

Frisina et al.[6] previously discussed a similar technique in which two needles were used. To the best of our knowledge, this is the first formal description of the term “needle-assisted iris-claw lens implantation (NAIL) technique,” a novel, single-handed method of iris-claw IOL fixation that utilizes a 10-0 prolene straight needle as an internal guide and pivot during enclavation, enhancing precision, centration, and surgical efficiency.

Preoperative Evaluation

Thorough anterior and posterior segment evaluations were performed using slit-lamp biomicroscopy, fundus examination, and gonioscopy. Key considerations for surgical planning include corneal health, anterior chamber depth, iris condition, systemic comorbidities, and bleeding risk. Pilocarpine was instilled preoperatively for pupillary constriction.

Surgical Technique

Herein, we present a novel technique that is reliable and repeatable and simplifies the iris-claw lens implantation with utmost precision. [Video 1]

1. A 10-0 prolene straight needle (16 mm) was introduced transcorneally across the horizontal meridian (3 to 9 o’clock), anterior to the iris [Fig. 1].

2. Anterior vitrectomy was performed in all cases to ensure a clear visual field was achieved.

3. A corneal or scleral incision (5.4 mm) was made for lens insertion.

4. The anterior chamber was filled with viscoelastic material, and the iris-claw IOL was inserted with its concavity facing the cornea.

5. Holding the optic centrally, one haptic is gently tilted and enclavated under the iris at 3 o’clock using a prolene needle as a pivot [Fig. 2].

6. The second haptic was enclavated at 9 o’clock, ensuring that the fixation points were diametrically opposite each other [Fig. 3].

7. Once the enclavation is complete, the needle is carefully withdrawn, and the incision is sutured with 10-0 nylon.

8. Peripheral iridectomy was performed to avoid a postoperative pupillary block.

9. Adequate viscoelastic washout was performed to prevent postoperative IOP increase.

Figure 1.

10-0 prolene needle inserted from the nasal to temporal limbus acting as a guiding wire

Figure 2.

Iris-claw IOL centered in the anterior chamber below the straight needle for centration

Figure 3.

Enclavation of both haptics of the iris-claw IOL with the help of a straight needle

This needle-guided approach eliminates the need for a second instrument, reduces the need to switch hands, and enhances symmetry and centration [Fig. 4].

Figure 4.

Perfect centration of the iris-claw IOL achieved with a round pupil

Only one hand is required for this technique compared to the cumbersome standard technique of changing hands to enclavate both the haptics. In addition to being less tedious, it also helps achieve perfect IOL centration and aids precise iris enclavation by eliminating the need for a second instrument, thus making this an extremely effective technique, even for novice surgeons. The needle acts as a third hand and anterior chamber maintainer. A similar technique was described earlier by Frisina et al.[6], who used a 30-gauge needle to engage the tip of a long straight needle and guide it to the opposite exit.

Discussion

Traditional iris-claw lens techniques often face challenges, such as asymmetric fixation, increased surgical time, and complications, including pigment dispersion and iatrogenic iris trauma. Horizontal pupil ovalization, reported in up to 44% of cases, is a common postoperative concern, especially when the enclavation is asymmetric or performed too close to the pupillary margin.[7]

By using a prolene needle as a temporary anterior chamber maintainer and guiding pivot, NAIL improves haptic alignment and significantly reduces surgical complexity, even for novice surgeons. The “third hand” effect of the needle enables single-handed enclavation with precision, thereby minimizing the need for intraocular manipulation.

In standard iris-claw IOL implantation, centration is unguided, but surgeons may use manual or image-guided methods. The manual technique involves marking the horizontal axis at the slit lamp, 180° apart at the limbus, using a marker pen, slit beam, or a fine corneal scratch for lasting visibility. Image-guided systems such as Callisto, Z Align, Verion, OTAS, iTrace, TrueGuide, ORA, and LENSAR-IntelliAxis use high-resolution preoperative images of ocular landmarks to assist in precise intraoperative alignment.[8] In the NAIL technique, neither of these methods are required for centration since the needle itself acts as a guide for centration.

Although Frisina et al. previously used a dual-needle technique for similar support, our method simplifies the process by using a single straight needle without requisite for additional instruments, making it more accessible in resource-constrained settings.

Conclusion

The NAIL technique represents a reliable and elegant modification of iris-claw IOL implantation, offering excellent centration and ease of surgery. This technique reduces the risk of postoperative complications, particularly in eyes with complex anterior segment anatomy or systemic risk factors. We recommend its inclusion in the armamentarium of every cataract surgeon, with further evaluation warranted through larger cohort studies and longer follow-up.

Author contribution

Involved in the design and conduct of the study (PP, MDR); data collection (PP); analysis and interpretation of results (PP, MDR); preparation of the manuscript and literature search (PP, MDR); review of the manuscript (MDR); final approval (MDR).

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Hyderabad Eye Research Foundation and Hyderabad Eye Institute, Hyderabad, India.