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Updates in pediatric cataract surgery
Experts review some of the latest techniques and surgical choices in these challenging patients.
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Pediatric cataracts may be unilateral or bilateral, congenital or acquired, and represent about 5% to 20% of global pediatric blindness. Pediatric cataract surgery can be challenging both in the operating room and after surgery with regard to clinical management and close follow-up, which are essential for an optimal visual outcome and avoiding amblyopia. Unlike adult cataract surgery, pediatric cataract surgery requires a multidisciplinary approach that monitors and treats all aspects of vision and vision-related function in these growing children. Advances in surgical techniques and IOLs have continued to improve the healing phase and contribute to improved visual quality in this age group. Improved wound construction and added surgical options with the performance of anterior and posterior capsulotomies, with or without anterior vitrectomy, have elevated the quality of these surgeries. However, various challenges continue to face the pediatric cataract surgeon.
In this column, Drs. Abhay Vasavada and Vaishali Vasavada describe various advances in pediatric cataract surgery and address some of the surgical choices and difficult questions that continue to face these surgeons.
Thomas “TJ” John, MDOSN Surgical Maneuvers Editor
Over the last decade, advances in technology and surgical techniques have brought pediatric cataract surgery into the modern age. This article will highlight recent updates in pediatric cataract surgery, in terms of both techniques and surgical paradigms that govern these techniques.
Surgical technique
Smaller incisions are becoming the norm in pediatric cataract surgery, similar to adult surgery, as they allow maintenance of a closed chamber and superior intraoperative performance.
Anterior capsule management
Source: Abhay R. Vasavada, MS, FRCS, and Vaishali Vasavada, MS
Manual anterior continuous curvilinear capsulorrhexis (ACCC), automated vitrectorhexis and Fugo plasma blade-assisted capsulotomy are popular options. Manual ACCC is the gold standard for ACCC but can be difficult in elastic pediatric capsules. Femtosecond laser-assisted cataract surgery promises to be a precise and predictable tool for performing ACCC. The laser can be docked onto the patient’s eye under anesthesia, and a desired size and centration of ACCC can be chosen based on real-time anterior segment OCT guidance (Figures 1 and 2). Newer modalities such as Zepto precision pulse capsulotomy (Mynosys Cellular Devices) and CAPSULaser technology (Excellens) also appear exciting. Microincision capsulorrhexis forceps and high-viscosity ophthalmic viscosurgical devices are essential adjuncts that help to achieve a desired size of ACCC. Trypan blue staining not only improves visibility in eyes with poor red reflex but is also useful for beginners because it makes the anterior capsule less elastic and aids in performing ACCC (Figure 3).
Posterior capsulotomy and anterior vitrectomy
It is a standard practice to perform a primary posterior capsulotomy (PPC)/capsulorrhexis (PCCC) with or without anterior vitrectomy in younger children (up to 8 years old). The primary objective is to reduce or retard the development of visual axis obscuration (VAO), which is the most common complication after pediatric cataract surgery (Figure 4).
Although manual PCCC offers strong edges and has a controlled size (Figure 5), it is difficult to perform. Once again, the femtosecond laser can be of great assistance in creating a circular, centric posterior capsulotomy (Figure 6). Vitrectorhexis may be performed through the limbal or pars plana route. The advantage of pars plana vitrectorhexis after IOL implantation is that it ensures desired in-the-bag IOL placement that may be jeopardized if the PCCC is not of an adequate size and centration.
Most phacoemulsification systems are equipped with high cut rate vitrectors and are compatible with 23- or 25-gauge vitrectomy. An MVR knife or a 23-gauge trocar cannula system is used to enter the pars plana region 1.5 mm to 2 mm behind the limbus. The vitrector is then inserted through this incision, and irrigation remains in the anterior chamber. We now prefer to perform anterior vitrectomy through the pars plana approach because it avoids upward traction on the vitreous (Figure 7).
Intracameral injection of preservative-free triamcinolone acetonide helps to identify vitreous better by staining it and thereby helps surgeons to check for adequacy of anterior vitrectomy (Figure 8). We have described a technique to render the vitreous visible and ensure a thorough, complete anterior vitrectomy in pediatric cataract surgery using preservative-free triamcinolone acetonide.
IOL implantation in unilateral cataracts
Although IOL implantation is now widely accepted in children older than 2 years, in infants there is still some controversy. Recently, a randomized, multicenter clinical trial comparing primary IOL implantation vs. contact lens wear was conducted in children younger than 7 months of age with unilateral cataracts. At 4.5 years follow-up, there was no significant difference in the median visual acuity whether an IOL was implanted or not. However, there were significantly more adverse events and a higher reoperation rate in eyes that received a primary IOL. Based on this study, the authors recommend that primary IOL implantation in unilateral cataract patients younger than 7 months of age should be reserved for select cases. Another prospective cohort study in children younger than 2 years of age reports that, in unilateral cataracts, there is no added visual benefit or protection from glaucoma with primary IOL implantation. However, IOL implantation increased the odds for additional anesthesia in this young population. Other studies have reported that primary IOL implantation in unilateral cataracts is associated with better visual acuity.
Thus, based on the available evidence today, it is fair to conclude that unilateral cataracts carry an inherent risk of amblyopia and despite best efforts are prone to develop poor visual outcomes. IOL implantation should be the goal in all older children, but in those younger than the age of 1 year, the risks of complications and reoperations should be carefully weighed against the potential visual benefit, keeping in mind compliance with contact lens wear.
IOL implantation in bilateral cataracts
As in unilateral cataracts, the debate on whether or not to perform primary IOL implantation is only in children younger than 2 years of age. Recently, in a study published using the Delphi approach in pediatric cataract management, 16 pediatric cataract surgeons from around the world were asked about their minimum age for primary implantation of IOLs in bilateral cataracts, and no consensus could be reached among these surgeons.
Several studies are coming out that show good visual outcomes with acceptable complications in bilateral cataract patients younger than 2 years.
At our center, we performed a prospective, randomized clinical trial, currently under peer review, evaluating primary aphakia vs. primary IOL implantation in children younger than 2 years of age with bilateral cataracts. The presence of an IOL ensured a much faster visual recovery, with complication rates being comparable between the two groups.
Thus, it is fair to conclude that with good surgical experience and tight follow-up, IOL implantation in children younger than 2 years of age is an acceptable modality. It offers partial albeit constant visual rehabilitation without relying on patient compliance in the developmentally crucial age group.
Alternative approaches to reduce visual axis obscuration
Several strategies to combat VAO are being used by surgeons, and ongoing research is being directed toward preventing or even delaying VAO, especially in young children. Two approaches that promise to reduce VAO and avoid anterior vitrectomy are posterior optic capture of IOL and in-the-bag IOL.
Tassignon has designed a unique IOL in which anterior and posterior capsulorrhexes of identical sizes are tucked into grooves of the IOL. The advantage of this approach is that the lens epithelial cells are sequestered between the two leaflets, and VAO is avoided. Further, because there is no migration of the lens epithelial cells behind the IOL optic, there is no need to perform anterior vitrectomy. Long-term studies with this IOL have shown favorable results in pediatric eyes.
Gimbel and colleagues first reported posterior optic capture of IOL through a posterior capsulorrhexis as a means to avoid vitrectomy and prevent VAO in children. However, the idea never became popular. Now, with newer IOL materials and designs, there is renewed interest in optic capture for both adults and children. In a randomized clinical trial, we included children from 0 to 4 years of age and found that VAO and complications were comparable in eyes that underwent in-the-bag IOL implantation of a three-piece hydrophobic acrylic IOL along with anterior vitrectomy vs. optic capture without anterior vitrectomy (Figure 9). An added advantage of posterior optic capture, particularly in eyes with trauma and ruptured anterior capsules, is that the IOL is locked into position, and decentration or tilt is eliminated. Therefore, wherever optic capture is possible, it may bring about a paradigm shift in surgical management by avoiding anterior vitrectomy, a procedure whose long-term risks and consequences are unknown.
Summary
While dramatic advances have occurred in this field over the past 10 years, some technical aspects of surgery, changing refraction and functional outcomes continue to pose significant problems. Primary management of the posterior capsule is mandatory depending on the age of the child at surgery. With refinements in surgical techniques, improvisation of IOLs and better understanding of growth of the pediatric eye, in the coming years IOL implantation is likely to become an established mode of treatment of children even in the youngest age group.
- References:
- Gimbel HV, et al. J Cataract Refract Surg. 1994;doi:10.1016/S0886-3350(13)80659-1.
- Hosal BM, et al. J Cataract Refract Surg. 2002;doi:10.1016/S0886-3350(01)01028-8.
- Saini JS, et al. J Cataract Refract Surg. 2003;doi:10.1016/S0886-3350(03)00229-3.
- Serrafino M, et al. Br J Ophthalmol. 2016;doi:10.1136/bjophthalmol-2015-307287.
- Solebo AL, et al. Br J Ophthalmol. 2015;doi:10.1136/bjophthalmol-2014-306394.
- Vasavada AR, et al. J Cataract Refract Surg. 2017;doi:10.1016/j.jcrs.2017.07.022.
- For more information:
- Abhay R. Vasavada, MS, FRCS, and Vaishali Vasavada, MS, can be reached at Raghudeep Eye Hospital, Gurukul Road, Memnagar, Ahmedabad – 380052, Gujarat, India; email: icirc@abhayvasavada.com.
- Edited by Thomas “TJ” John, MD, a clinical associate professor at Loyola University at Chicago and in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. He can be reached at email: tjcornea@gmail.com.
Disclosures: John, Vasavada and Vasavada report no relevant financial disclosures.