Summary
Infants and young children under 8 to 9 years of age who are born with or develop cataracts are at risk of developing deprivation amblyopia, which can result in severely decreased vision, depending on the size, location, and density of the lens opacity, age at onset, duration of visual deprivation, and whether the cataract is unilateral or bilateral. Timely intervention is crucial for the optimal treatment of infantile and juvenile cataracts. Cataract extraction is an early, critical step in the management of cataracts in the pediatric population, after which the treatment of amblyopia and monitoring for complications, including visual axis opacification and glaucoma, continue for years and are equally critical.
13 Pediatric Cataract Surgery
13.1 Goals
The goal of cataract surgery in infants and children is to clear the visual axis in an eye with visual deprivation causing amblyopia and then closely monitor and treat amblyopia and any complications that occur.
13.2 Advantages
Although nonsurgical treatments including pupillary dilation, correction of refractive error, and occlusion therapy may be used to treat small cataracts that appear “borderline” amblyogenic, cataract surgery is the sole treatment available to treat visual deprivation. Pupillary dilation with phenylephrine and tropicamide can be considered as a nonsurgical treatment option for small paracentral cataracts. 1 Cyclopentolate and atropine are avoided due the risk of anticholinergic side effects on the central nervous system in infants 2 and due to resulting cycloplegia. However, availability of phenylephrine and tropicamide eye drops on an outpatient basis is often limited, even when prescribed, and these drops also require more than once daily dosing and may result in inadequate pupillary dilation. Early treatment is crucial in infants and young children due to the dense amblyopia that occurs with visual deprivation, which is more refractory to amblyopia treatment if treated later.
13.3 Expectations
The expectation of pediatric cataract surgery is clearing of the visual axis to allow visual development and improvement of visual acuity.
Intraoperatively, pediatric eyes are different from adult eyes, not only due to their smaller size and steeper corneal curvature. There is less corneal and scleral rigidity, the capsule is more elastic, and greater inflammation can occur postoperatively. 3 There is increased posterior pressure, which can result in easy shallowing of the anterior chamber during surgery. In addition, the smooth muscle tone of the iris dilator is reduced, similar to that seen in intraoperative floppy iris syndrome in adults on systemic alpha-1 antagonist medications. 4
The visual acuity in infants with cataracts associated with persistent fetal vasculature (PFV) may be limited by other ocular abnormalities including abnormal macular anatomy. PFV has a higher risk of complications such as hemorrhage and glaucoma, and is also commonly associated with microphthalmia, resulting in more challenging cataract surgery.
The visual prognosis due to amblyopia and long-term monitoring and treatment is discussed with the patient’s family who should understand that refractive correction will be needed postoperatively and bifocal glasses will be needed for children 2 to 3 years of age and older.
13.4 Key Principles
The timing of surgery for congenital cataracts should be before 6 weeks of age for unilateral cataracts and before 2 months of age for bilateral cataracts, 5 , 6 scheduled a maximum of 2 weeks apart.
For young children with “borderline” cataracts, once it is determined that nonsurgical treatments including pupillary dilation, correction of significant refractive error, and/or occlusion therapy are not adequately improving the visual acuity, cataract surgery is considered.
The cataract and lens material are removed, leaving capsular support for intraocular lens (IOL) placement at the time of cataract extraction or when the child is older.
Phacoemulsification is rarely, if ever, needed in the removal of pediatric cataracts, so the surgeon may use bimanual irrigation-aspiration handpieces or bimanual irrigation and anterior vitrectomy handpieces, which can be used for both aspiration and cutting.
A posterior capsulotomy with anterior vitrectomy is performed during most pediatric cataract surgeries due to the rapid posterior capsule opacification that occurs in infants and young children, 7 which results in recurrence of visual deprivation, requiring additional surgical treatment.
Anterior vitrectomy is recommended at the time of posterior capsulotomy, as the anterior hyaloid face can act as a scaffold for proliferating lens epithelial cells if only a posterior capsulorhexis is performed. 1
Placement of an IOL requires a larger wound, and the IOL can act as a scaffold for proliferating lens epithelial cells, which can result in recurrence of visual deprivation, even after posterior capsulotomy and anterior vitrectomy. The Infant Aphakia Treatment Study (IATS) has recommended leaving infants less than 7 months of age aphakic due to a greater frequency of adverse events and additional surgical procedures with IOL placement in this age group. 8 , 9 The Toddler Aphakia and Pseudophakia Study found that IOL placement is safe in children older than 6 months and younger than 2 years of age. 10 IOL implantation done later may also allow the IOL power to be chosen with better accuracy.
Visually significant cataracts occurring in older children and teenagers, who are not at risk of developing amblyopia, are treated with implantation of an IOL with or without a posterior capsulotomy with anterior vitrectomy, depending on the patient’s expected ability to tolerate laser capsulotomy, if needed.
Following cataract extraction, the refractive error is determined and corrected with extended-wear contact lenses and/or with glasses, ideally within 2 to 3 weeks, with the understanding that the refractive error will change over time.
13.5 Indications
In preverbal infants and toddlers with cataracts, a poor fixation behavior with a strong ocular preference, if the cataract is unilateral, and a poor red reflex through an undilated pupil are indicative of visual deprivation and warrant cataract surgery. 1
When the visual acuity can be reliably measured in a child and is at least in the 20/30 range in both eyes, which would allow driving in most states in the United States, or is in the 20/50 range with normal visual acuity in the fellow eye, the surgeon should have a discussion with the family regarding the balance of the potential benefits and risks of pediatric cataract surgery, as well as the timing of surgery. 11
Older children and teenagers who are not at risk of amblyopia are treated with cataract surgery if the vision is decreased and affecting daily activities, similar to the indications for adult cataracts.
13.6 Contraindications
There are few relative contraindications for cataract surgery in infancy and early childhood due to the dense amblyopia that occurs from visual deprivation.
If the cataract is due to trauma with other severe ocular injuries that increase the risk of complications and limit the visual potential, cataract surgery may not be recommended.
Cataracts with significant zonular instability due to trauma or connective tissue disorders may be best addressed by a vitreoretinal surgeon with co-management in the early postoperative period, followed by continued management of amblyopia by the pediatric ophthalmologist.
Weighing the risks and benefits of cataract surgery in children with cataracts that appear “borderline” amblyogenic should be discussed with the patient’s family, including the extensive postoperative care that is required which may be challenging for some families, so that the potentially limited visual improvement may be slightly outweighed by the risks.
The recommendation for IOL placement depends on the age of the child, as per IATS recommendations, and also the family’s ability to manage care of contact lenses, particularly in unilateral cataracts. Although implantation of an IOL is not an absolute contraindication in infants, the IATS found that young infants in whom an IOL was placed were at a significantly higher risk of requiring additional intraocular surgeries, 8 which were generally uncomplicated but every return visit to the operating room carries risks.
The risks of anesthesia are taken into consideration when determining the timing of surgery for children with chronic and acute diseases.
13.7 Preoperative Preparation
The assessment of a pediatric cataract includes a complete history, including the laterality, appearance, and age of onset of the cataract, as well as concerns about vision. Medical and birth history are also obtained. The examination includes an age-appropriate assessment of visual acuity, intraocular pressure, and a slit lamp examination, or at least a penlight examination of the anterior segment in infants and young children. The red reflex prior to pupillary dilation should be assessed with a retinoscope or direct ophthalmoscope to evaluate the size and location of the lens opacity relative to the visual axis. A dilated fundus examination is performed in both eyes to fully assess the lens and to examine for other ocular abnormalities that may affect visual development. Cycloplegic refraction is evaluated in both eyes to determine if a component of refractive amblyopia may be present and to aid in determining the refractive goal if IOL placement is planned for a patient with a unilateral cataract. If there is a limited view to the fundus due to the cataract, a B-scan ultrasound should be performed and a dilated fundus examination performed after the cataract is removed, either at the end of surgery while in the operating room or during a postoperative visit. Most infants and children tolerate B-scan ultrasound well, although an assessment of all quadrants of the eye may be limited. The ophthalmic examination also includes an evaluation of the ocular alignment, at least by corneal light reflex testing, as strabismus due to visual deprivation may be present. If strabismus persists or develops after cataract surgery with continued amblyopia treatment, strabismus surgery may eventually be needed. If bilateral cataracts are present, systemic causes including infectious, genetic, and metabolic diseases are considered and further evaluation recommended, usually in coordination with the patient’s pediatrician. Systemic and ocular comorbidities, if present, and the morphology of the cataracts are examined to consider possible underlying etiologies of bilateral cataracts. Family history of infantile or juvenile cataracts is also obtained, in addition to examining immediate family members in the office, if possible. Lamellar and nuclear cataracts presenting in infancy and early childhood are often familial. 1
Cooperative children of 2 to 3 years and older may be able to undergo optical biometry in the office. If the cataract is dense or the child is not cooperative, axial length measurements with immersion A-scan ultrasound and keratometry are performed while the child is under anesthesia. The refractive goal when placing an IOL depends on the patient’s age and the refraction of the fellow eye in unilateral cases. Suggested refractive goals based on age are listed in Table 13.1. 1 , 12 Most pediatric cataract surgeons use hydrophobic acrylic one-piece or three-piece monofocal IOLs. 13 The axial length and location of the IOL in the capsule or in the ciliary sulcus are also considered when selecting the IOL power and IOL calculation formula used. The selection of the IOL power for an intended refractive outcome is error-prone, especially in young children with smaller eyes, more shallow anterior chamber depths, changing corneal curvatures, and unpredictable axial length elongation. 1 , 8
Age | Refractive goal (diopters) |
6–12 months | + 5.00–6.00 |
1 year | + 4.00–5.00 |
2 years | + 4.00 |
3 years | + 3.00 |
4 years | + 2.00 |
5 years | + 1.00 |
6–7 years | + 0.50 |
8 years and older | Plano |
Although cyclopentolate 0.2% and phenylephrine 1% are typically used in infants for pupillary dilation, this combination may not provide adequate pupillary dilation for surgery. Cyclopentolate 1%, phenylephrine 2.5%, and mydriacyl 1% can be instilled two to three times every 5 minutes to dilate the pupils before cataract surgery. The patient is monitored while under anesthesia and in the postoperative care unit for any systemic adverse effects from the topical medications. In addition, 0.5 mL of 1:1,000 nonpreserved epinephrine per 500 mL of balanced salt solution can be added for intraocular irrigation during surgery.
An examination under anesthesia before the start of surgery may be performed to evaluate the intraocular pressure, pachymetry, gonioscopy, and precise measurements of corneal diameters if unable to be reliably assessed in the office. Ocular biometry may also be performed at this time if needed. Following the examination under anesthesia, the operative eye is prepped with 5% betadine with attention to careful cleaning of the eyelashes. A fenestrated clear drape covers the patient’s face and body, and a large transparent film dressing cut in half is used to completely cover the upper and lower eyelashes and position them away from the globe (Fig. 13.1). The surgeon is positioned at the top of the patient’s head for superior incisions which may decrease the risk of complications related to injury and endophthalmitis, and the surgical microscope is adjusted. An appropriately sized wire eyelid speculum or adjustable eyelid speculum is placed, and the eye is inspected once more under the microscope.
The instruments and medications recommended for pediatric cataract surgery are listed in Table 13.2.
13.8 Operative Technique
13.8.1 Cataract Extraction without IOL Implantation
Colibri forceps are used to grasp the eye, and then a paracentesis blade is used to enter the anterior chamber at approximately 10 o’clock (Fig. 13.2). A 4–0 silk traction suture can be placed around the superior rectus insertion to help position the globe during surgery.
Trypan blue may be used to stain the anterior capsule to better visualize the capsule for the capsulotomy.
Once the anterior capsule is stained, the anterior chamber is irrigated with balanced salt solution and then filled with viscoelastic.
A nick in the anterior capsule can be made with a cystotome needle. If the anterior capsule is smooth without a membranous plaque, a capsulorhexis can be performed using small incision forceps, such as ILM forceps, through the paracentesis wound. Alternatively, a second paracentesis wound is created at approximately 2 o’clock, 100 to 120 degrees away from the first wound, and the bimanual anterior vitrectomy handpieces are used for a vitrectorhexis (Fig. 13.3). The anterior vitrector is inserted with the port initially facing down to start the anterior capsulotomy at the nick created with the cystotome (Fig. 13.4a). Suggested settings for a 23-gauge anterior vitrector are a cut rate of 800 cuts per minute (cpm), maximum vacuum of 100 to 150 mmHg, and aspiration of 20 to 30 mL/minute in I/A-cut mode. A high irrigation pressure is used during surgery to help maintain the anterior chamber. An anterior chamber maintainer is helpful if the anterior chamber shallows easily during surgery. The port may then be rotated to face up (Fig. 13.4b) to enlarge the capsulotomy without prematurely removing lens material to protect the posterior capsule. The anterior capsular opening should be round and approximately 5 mm, slightly smaller than the size of the dilated pupil in most patients. The bimanual anterior vitrectomy handpieces may be switched to ensure a centered and round anterior capsulotomy.
Next, the anterior vitrector is used to remove the lens material, primarily with aspiration. Suggested settings are maximum vacuum of 400 mmHg and aspiration of 20 to 25 mL/min, with a cut rate of 250 cpm used intermittently for clearing the port when needed. The handpieces can be switched to completely remove peripheral cortical material with a stripping motion once the cortex is engaged. Bimanual irrigation and aspiration handpieces can also be used for removal of the cortex.
The anterior vitrector is then used to create a posterior capsulotomy (Fig. 13.5a). Posterior capsulorhexis with a cystotome and small incision forceps has also been described. Suggested settings are to use cut-I/A mode and increase the cut rate to 1,000 cpm, and maximum vacuum of 100 to 150 mmHg. The posterior capsulotomy is enlarged to be similar in size to the anterior capsulotomy (Fig. 13.5b).
An anterior vitrectomy is then performed to include the space under all 360 degrees of the posterior capsular opening. Suggested settings are to use cut-I/A mode with a high cut rate of 1,000 to 1,500 cpm, and maximum vacuum of 100 to 150 mmHg. The vitrector is then positioned in the anterior chamber to remove any vitreous that may have migrated forward and any remaining viscoelastic.
Acetylcholine is then injected into the anterior chamber either on a blunt cannula or by injecting through the infusion line before the instruments are removed from the eye. The pupil will constrict and should remain round. If there is peaking of the miotic pupil due to distortion from anteriorly prolapsed vitreous, additional anterior vitrectomy is performed in the anterior chamber.
If the patient is to be left aphakic, the cut rate is then decreased to a very low rate with low vacuum at 100 mmHg in I/A-cut mode. With the port of the vitrector facing down over the superior peripheral iris, a surgical iridotomy is created, usually with one cut (Fig. 13.6). Bleeding may occur at the iridotomy site which can usually be controlled by repressurizing the anterior chamber with irrigation.
The cut rate is then increased again in cut-I/A mode with the port facing up. The anterior vitrector is kept cutting as the instruments are withdrawn from the anterior chamber with the port facing up or to one side to avoid inadvertent engagement of the iris. Cellulose sponges are used to assess the wounds for vitreous, while also inspecting the pupillary margin for movement indicating the presence of vitreous to the wound, which may be manually cut first, and then additional anterior vitrectomy is performed in the anterior chamber.
The paracentesis wounds are closed with 10–0 polyglactin suture and rotated to bury the knot as much as possible toward the conjunctival side of the limbus. The irrigation handpiece may be kept in place while closing the first wound to help maintain the anterior chamber while placing the first suture.
Balanced salt solution is used to inflate the anterior chamber to a physiologic intraocular pressure by palpation. A bubble of filtered air may be injected into the anterior chamber to prevent influx of fluid.
The wounds are checked again with cellulose sponges to ensure they are watertight.
Subconjunctival injections of cefazolin and dexamethasone are administered in the superior quadrants.
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