Pediatric Cataract

P. Nucci

• Verlag: S. Karger
• Jahr: 2016
• ISBN:
  9783318058208
• Thema: Medicine
• Thema: Pediatric Medicine

This volume presents the latest trends in the management of pediatric cataract. It covers everything from the role of genetic and systemic work-up to the state of the art in surgery. Discussions include ocular modifications after surgery, the incidence and risk factors of post-surgery complications, and the management of complex cases. There is a chapter dedicated to post-aphakic glaucoma, a new insight to visual rehabilitation, and a summary of a recently published Delphi project. Pediatric ophthalmologists looking for the latest research in the management of cataract will find this publication to be invaluable reading. It will also be useful to general ophthalmologists, residents, and fellows, as well as to medical students and pediatricians who seek an update for daily clinical practice.

Nucci P (ed): Pediatric Cataract.
Dev Ophthalmol. Basel, Karger, 2016, vol 57, pp 85-106 (DOI: 10.1159/000442505)

______________________

Complex Cases in Pediatric Cataract

Preeti Patil-Chhablani^a · Ramesh Kekunnaya^a · Kanwall Ken Nischal^b

^aL V Prasad Eye Institute, Hyderabad, India; ^bChildren's Hospital of Pittsburgh of UPMC, Pittsburgh, Pa., USA

______________________

Abstract

This chapter describes the techniques and pitfalls that the reader may come across when dealing with complex pediatric cataract cases. Each eye in these circumstances is unique, and the examples and general advice shared are intended to help the reader develop a plan for surgery and a road map to avoid potential problems. As in all types of surgery, careful planning is essential. The old saying ‘Fail to prepare, then you prepare to fail’ is no more true than when dealing with children who have complex cataract. In this chapter, the following circumstances where pediatric cataract may be seen are discussed: retinoblastoma, retinopathy of prematurity, lenticonus, congenital rubella syndrome, trauma, microcornea, pediatric uveitis, Hallermann-Streiff syndrome, Stickler syndrome, Lowe syndrome, subluxated lens, and after previous intraocular surgery (glaucoma, keratoplasty).

© 2016 S. Karger AG, Basel

Retinoblastoma

Children with retinoblastoma may develop cataracts as sequelae of the management of the primary disease by external beam radiotherapy. Cataracts may also be a manifestation of the primary disease processes itself [1, 2]. Surgical management is indicated not only for visual rehabilitation but also to improve visualization of the tumor and to aid further monitoring and treatment. Cataract surgery is challenging in patients with retinoblastoma due to several factors. Since tumor recurrence may be seen after intraocular surgery, tumor quiescence must be ensured before planning cataract surgery. The improvement in visual acuity is not dependent upon cataract surgery alone and is influenced by the extent of retinal/macular involvement and amblyopia.

Preoperative Considerations

Although there is no consensus about the optimal length of quiescence of the tumor before intraocular surgery, the longer the period of quiescence, the lesser are the chances of tumor recurrence. A minimum period of 9-12 months is desirable prior to surgery [3]. A careful fundus examination is a must prior to surgery, not only to examine the tumor but also to note areas of local retinal detachment, vitreous adhesions, etc. If fundus examination is not possible due to lenticular opacity, an ultrasound B-scan is essential prior to planning surgery. A team approach is desirable, and it is best for the surgeon to discuss the need to perform a primary posterior capsulotomy (PPC), anterior vitrectomy (AV) and intraocular lens (IOL) implantation with the treating oncologist.

Parental counseling prior to surgery is of extreme importance. A realistic discussion about the need for cataract surgery, the possibility of a recurrence, need for further adjuvant chemotherapy/radiation, the visual prognosis and the rare possibility of enucleation is a must before undertaking the procedure.

Surgical Procedure

A higher rate of recurrence has been noted in eyes where a pars plana approach was taken. Hence, a clear corneal approach is preferable [4]. A clear corneal incision is also easily visible. The chances of visualization of subconjunctival seeding are higher when a scleral incision is avoided.

A large anterior capsulorrhexis is preferred in order to avoid capsular phimosis so that the view of the posterior segment is not hindered. However, it is still best to make the anterior opening smaller than the optic size to avoid later anterior displacement of the IOL. If phimosis is suspected within 8 weeks of primary surgery, radial cuts can be made using a YAG laser (in older children) or surgically back in the operating room in younger children. A PPC is best avoided in older children. In situations where it must be done (such as in young children or in the presence of a posterior capsular plaque), a manual capsulorrhexis is preferred (online suppl. video 1; for all online suppl. material, see www.karger.com/doi/10.1159/000442505). The vitreous face should be left untouched wherever possible to decrease the possibility of dissemination of vitreous seeds. If a vitrectomy is performed, it is best to send a vitreous sample for histopathological analysis to look for tumor cells in the vitreous. This information must be communicated to the treating oncologist as early as possible. There are no specific contraindications for implanting an IOL under such conditions. In contrast, such patients are poor candidates for contact lens wear due to dry eye caused by radiation therapy, and hence, IOL implantation is preferred.

Postoperative Care and Results

Extensive use of lubricants in the postoperative period is mandatory, as there is a high chance of dry eye in these children. Most studies have shown good surgical results after cataract surgery in eyes with retinoblastoma. The recurrence rates reported in the literature range from 0 to 45% [3]. The ultimate visual outcome is dependent upon the location and size/stage of the retinoblastoma, visual rehabilitation, prompt refractive correction and amblyopia management.

Cataract in Retinopathy of Prematurity

Cataracts in eyes with retinopathy of prematurity (ROP) either are associated with the disease or are sequelae of treatment (laser photocoagulation and/or vitreoretinal surgery) for the ROP [5].

Preoperative Considerations

If a cataract is the result of complications from laser therapy or inadvertent needle injury during anti-vascular endothelial growth factor injection, surgery may well need to be done early due to the development of an opaque lens. In this scenario, when the infant may be at term based on the postgestational age and yet 16 weeks postnatal, the need for rapid, efficient surgery is mandatory. However, if the cataract develops later, and even months later, the considerations for surgery change, and in such cases, the eyes tend to be myopic (axial and lenticular) and may have higher-than-average axial lengths. Careful biometry is a must in these eyes. The cataract must be examined meticulously; one must look for the presence of posterior capsular dehiscence (which may preexist due to intraoperative lens touching during previous vitreoretinal surgery), zonular weakness and the extent of pupillary dilatation. All these factors should be taken into consideration while formulating a surgical plan. The parents of the child must be given a realistic idea about the extent of visual acuity that the child is expected to gain after surgery. The presence of retinal scarring, macular drag, extreme myopia, amblyopia, etc. may compromise the final visual acuity after successful cataract surgery. Of course, the younger the infant is at surgery, the more visual rehabilitation will play a role in the final outcome.

Surgical Considerations

Scenario 1: Infant with Opaque Lens Secondary to Laser Complication or Anti-Vascular Endothelial Growth Factor Injection

In these circumstances, the role of anesthesia is crucial. The infant should be paralyzed and have an appropriately low end-tidal CO₂ to ensure that there is minimal positive pressure during the surgery. In these cases, there are often posterior synechiae present, so the viscoelastic is used to ensure that these synechiae are adequately broken. In these infants, the eyes are small, so if iris hooks are used, too many entry wounds for a small corneal circumference are needed; it is best to instead use an instrument like a Kuglen hook to retract or push the iris away from the vitrector or aspirating hand piece. To ensure as rapid a surgery as possible (these infants often have other co-morbidities), a vitrector is used (150-200 mm Hg vacuum, 500 cpm cut rate) to create a large capsulotomy and aspirate the lens material. Attempting to place an IOL in these circumstances is not recommended; instead, capsule-sparing lensectomy needs to be performed to leave enough support for a secondary IOL later. If the iris is very inelastic because of the synechiae, it is worth considering mechanical enlargement of the pupil. Turning the vitrector cutter port face down, with the cutter ‘off’, breaches the posterior capsule. The capsule is aspirated into the port (it is seen to wrinkle), and at that moment, the cutter is turned ‘on’, thereby breaching the capsule. A posterior capsulotomy is performed, and an AV is also performed. The wounds are closed with 10/0 Vicryl, and it is worth placing either some intracameral preservative-free dexamethasone (2 mg) or some intracameral diluted preservative-free (10:1) triamcinolone (0.2 ml total volume).

Scenario 2: Older, Systemically Stable Child (>6 Months)

Scleral rigidity may be low in this child's eyes, and a high-molecular-weight viscoelastic material is desirable to maintain the anterior chamber while performing an anterior capsulorrhexis. In cases where previous retinal surgery has been done, silicon oil bubbles may be present in the anterior chamber. It is best to wash these bubbles out before beginning the surgery. A large anterior capsulorrhexis is preferred in order to facilitate a complete fundus evaluation in the future. Hydrodissection is best avoided since there may be weak areas in the posterior capsule that may not be evident preoperatively. The irrigating fluid flow rate/bottle height should be low. Primary capsulorrhexis, where required, must be larger. In cases where AV is required, a high-speed vitrector is desirable. It is best to limit vitrectomy to the anterior vitreous and avoid disturbing the core v...