Surgical management of subluxated cataracts is challenging, and the choice of the best surgical approach depends on the severity of lens dislocation, the extent of zonular dialysis, and the underlying etiology. In 2013, Hoffman et al. proposed a new classification to assess the severity of the lens dislocation that considers the percentage of pupil in mydriasis left uncovered by the lens: 0 − 25% in minimal to mild subluxation, 25–50% in moderate subluxation and more than 50% in severe subluxation [2]. In cases from minimal to mild zonular dehiscence (less than 3 contiguous clock hours) and non-progressive conditions, a successful outcome can be obtained with a 3-piece or single-piece IOL in the capsular bag. In eyes with moderate to severe dehiscence ( more than 3 clock hours of zonular laxity), a permanent capsular support, such as a Cionni CTR or a Ahmed CTS, should be placed [2]. The determination of the most suitable capsular tension device should consider the intraoperative conditions and patient characteristics.
It is worth noting that the creation of a centered and well-sized capsulorhexis is essential for the effective placement of the abovementioned capsular tension devices since they are contraindicated if any discontinuity of the anterior capsule is present. Nonetheless, creating a well-centered capsulorhexis is challenging in subluxated cataracts due to zonular instability that reduces the counter-traction forces that facilitate the capsulotomy. Femto-laser capsulotomy has been proposed in recent years, as it minimizes the amount of stress on the already compromised zonules [11, 12]. However, it is severely limited when the anterior capsule is too tilted or too posteriorly displaced [11].
In cases of complete posterior dislocation of the crystalline lens in the vitreous cavity, pars plana vitrectomy is required, whereas soft nuclei can be removed by lensectomy and hard nuclei are better managed by phacofragmentation [13]. An alternative approach to reduce ultrasound energy and the risk of retinal injuries is the extraction of the hard nucleus through a corneoscleral limbal incision [14]. Other surgical techniques that can be employed are pars plana vitrectomy with intravitreal phacoemulsification [15], pars plana vitrectomy combined with perfluorocarbon liquid-assisted phacoemulsification [16, 17], and nitinol basket-assisted pars plana vitrectomy [18]. These surgical approaches have proven to be effective in removing the crystalline lens from the vitreous cavity. However, they carry an increased risk of intra-operative and post-operative complications such as iatrogenic retinal breaks, vitreous hemorrhage, vitreous incarceration and retinal detachment [19, 20].
Previous techniques have been described for the management via pars plana of sinking nuclei during cataract surgery in the presence of posterior capsular tears. Packard described the PAL technique, where a spatula is inserted downward via the pars plana with its tip inclined to the posterior pole of the eye, placed behind the nucleus and subsequently used to lift the partially dropped nucleus forward into the anterior chamber. Surgery is completed by extending the wound and expressing the nucleus or by phacoemulsification with the protection of a sheet glide [4]. Chang and Packard, in 2003, described a modified PAL technique using Viscoat® where the tip of its cannula is used to lift the nucleus or nuclear fragments into the anterior chamber [5]. Lastly, Lifshitz et al. described the planned-PAL technique, where a spatula was inserted via the pars plana and used to lift the whole subluxated lens to the anterior chamber and then remove it through a scleral tunnel [6].
In the present study, we described the anatomical and functional outcomes of the “Viscolift technique.” This technique consists of injecting a cohesive viscoelastic substance into the retrolental space to raise and center the lens in cases of severely subluxated cataracts and this facilitates the surgeon in performing a centered capsulorhexis, preserving the capsular bag. In addition, it offers posterior support to stabilize the anterior chamber intraoperatively and, since the use of Healon is gentler than the spatula, it allows preservation of the posterior capsule [10]. The main finding of the present study was that the “Viscolift technique” effectively resulted in elevation and centration of the lens in all cases. Furthermore, we observed a significant improvement in BCVA and refraction in all cases 6 months after surgery, with an improvement from 0.5 ± 0.1 LogMar (20/63 Snellen) pre-operatively to 0.1 ± 0.1 LogMar (20/25 Snellen) six months after surgery, outlining this technique’s efficacy in managing severely subluxated cataracts. Chee at al. reported an improvement in BCVA from a median of 0.6 logMar pre-operatively to 0.2 logMar at one year in patients with severely subluxated cataracts treated with Femto-laser assisted capsulotomy [11]. Also, Chee and Jap reported a visual acuity of 20/40 or better after one year in almost 95% of eyes with traumatic subluxated cataracts treated with capsular tension devices [1]. Therefore, our results suggest that the “Viscolift technique” is at least as effective as previous surgical methods in terms of improvement in visual acuity in patients with severely subluxated cataracts.
According to the results of our study, the “Viscolift technique” showed to be a viable option in the presence of zonular disinsertion. It is worth noting that an essential prerequisite for the success of this surgical approach is a preoperative condition of phacodonesis, as the mobility itself facilitates the elevation of the lens with the viscoelastic substance. Therefore, it is crucial to assess the degree of phacodonesis before surgery to determine the appropriateness of this technique. Cohesive viscoelastic agents are particularly indicated for this surgical technique due to their ability to create and sustain an optimal space, as well as to facilitate lens recentering in instances of severe subluxation. Their rheological properties, marked by long-chain molecules, high molecular weight, and elevated viscosity enhance cohesion and ensure effective space maintenance, thereby facilitating precise lens repositioning [21]. Another result of the present study was that we did not encounter any complications intraoperatively or during the 6-month follow-up period, such as increased IOP, retinal tears, or retinal detachments, with the exception of two cases of CME that were successfully treated with topical medications. Furthermore, in none of the patients a pars plana lensectomy or vitrectomy for dropped nucleus or fragments or the use of fragmatome was necessary. Following surgery, a temporary rise in intraocular pressure may occur as a result of viscoelastic substances used during the procedure. This increase in pressure typically peaks 4 to 7 h after surgery and usually normalizes within a few days. In case of IOP increase, it can be managed effectively with either topical or systemic medications [21].
This study has several limitations such as the small number of patients included and the single-center study assessment. Therefore, a multicenter study with a larger number of cases should be performed to confirm the effectiveness of the technique. Additionally, further studies are needed to compare the “Viscolift technique” with other surgical approaches for severe subluxated cataracts, in order to understand its potential advantages over alternative surgical methods.
In conclusion, the management of subluxated cataracts represents a challenge, and the choice of the most suitable approach or device to address every specific situation is a demanding task for the surgeon. The results of the present study showed that the “Viscolift technique” is a safe and effective surgical approach for re-centering and elevating subluxated cataracts to facilitate capsulorhexis. Therefore, surgeons should consider this approach as a viable option for the management of patients with severe crystalline subluxation, intact capsular bags, and phacodonesis.
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