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Nucci P (ed): Pediatric Cataract.

Dev Ophthalmol. Basel, Karger, 2016, vol 57, pp 69–84 (DOI: 10.1159/000442502)

Complications of Pediatric Cataract Surgery Catherine Gasper Rupal H. Trivedi M. Edward Wilson Storm Eye Institute, Medical University of South Carolina, Charleston, S.C., USA

Abstract

Early detection and treatment is necessary in pediatric cataract patients to prevent future vision deprivation and amblyopia [1–4]. Vision loss from congenital cataract is primarily caused by amblyopia from stimulus deprivation and inhibition of eye development, especially in patients with late presentation. However, pediatric cataract surgery is not without risk. Postoperative complications in children vary based on the age at the time of surgery, type of cataract, and surgical technique. The risk of poor outcome is significantly greater in congenital cataract compared to developmental cataract [2]. Complications can involve the anterior or posterior portion of the eye and can occur intraoperatively or postoperatively. Herein, we describe postoperative complications after pediatric cataract surgery. Postoperative complications may be observed during the early postoperative period (e.g. wound leakage, intraocular pressure (IOP) spike, corneal edema, or anterior uveitis), after a few months or within a few years [posterior capsule opacification (PCO), glaucoma, or retinal detachment] or several years after cataract surgery (glaucoma or retinal detachment).

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Postoperative complications associated with cataract surgery in children vary significantly from those typically seen in adults. Pediatric patients are at an increased risk of problems after intraocular surgery due to increased ocular elasticity, heightened inflammatory reactions, and an elevated risk of postoperative trauma. Any complication is particularly important to detect early in children due to the potential for aberrant development, which may result in decreased visual acuity. Further, complications arise throughout the immediate and extended postoperative periods that may be challenging to detect given the difficulty of the clinical examination of some young patients. Herein, we address common complications observed during the immediate postoperative period and during Š 2016 S. Karger AG, Basel the months and years following cataract surgery in pediatric patients.

PCO is inevitable in very young children after cataract surgery if the posterior capsule is left intact. Even when primary posterior capsulectomy is performed, opacification may occur, and in this setting, it is referred to as visual axis opacification (VAO) rather than PCO. The incidence of PCO (posterior capsule intact) or VAO (after primary posterior capsulectomy) is a common postoperative outcome measure of pediatric cataract surgery (fig. 1a–d) [4–6]. Secondary opacification develops more frequently in younger children than in older children. This difference due to age may be attributed to increased uveal reactivity in younger children, leading to increased formation of inflammatory membranes [7]. A recent study of primary intraocular lens (IOL) implantation in children less than 4 years old with microphthalmia found that 15% of the patients developed VAO [8]. In fact, in children less than 4 years old, 100% of eyes go on to develop PCO if the posterior capsule remains intact. To prevent opacification and visual deprivation, posterior capsulectomy and anterior vitrectomy are performed [9]. These procedures significantly improve visual outcome and are positive predictors of final visual outcome due to a lower incidence of VAO [10]. Specifically, a recent study randomized twenty-seven children who were 4–14 years old to either receive posterior capsulectomy and anterior vitrectomy or to have their posterior capsule left intact after cataract extraction and primary IOL implantation. The study found better visual acuity at 6 weeks and 6 months in the group that underwent posterior capsulectomy and anterior vitrectomy compared to the control group. There was significantly less PCO in the treatment group and no significant difference in IOP between the two groups [11]. Another study found that posterior capsulectomy and anterior vitrectomy performed at the time of cataract extraction significantly improved visual outcome, regardless of primary or secondary IOL implantation [3].

Even after primary posterior capsulectomy and vitrectomy, eyes operated on during the first year of life are predisposed to developing reopacification of the visual axis in the form of lens proliferation into the visual axis (defined as lens regrowth extending into the pupillary space and interfering with vision) or pupillary membrane [12].

The 5-year results of the Infant Aphakia Treatment Study (IATS) included 2 (4%) eyes with lens proliferation obscuring the visual axis in the contact lens group and 23 (40%) such eyes in the primary IOL group [12]. A pupillary membrane was observed in 2 (4%) eyes in the contact lens group versus 16 (28%) in the IOL group.

The type of IOL used may also be a risk factor for developing a secondary membrane after cataract surgery. Different types of IOLs may have different lengths of time until opacification. For example, one study found that secondary membranes formed more quickly when polymethyl methacrylate (PMMA) lenses were implanted compared to acrylic lenses [13]. Eyes with traumatic cataract are more likely to develop PCO compared to those without traumatic cataract [14].

If PCO does develop, then YAG laser capsulectomy or surgical membranectomy can be performed [9].

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Nucci P (ed): Pediatric Cataract.

Dev Ophthalmol. Basel, Karger, 2016, vol 57, pp 69–84 (DOI: 10.1159/000442502)

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Posterior Capsule Opacification or Visual Axis Opacification

a

b

c

d

Fig. 1. a–d Various forms of PCO. Inset Pars plana capsulectomy and vitrectomy to clear visual axis opacification.

Glaucoma after pediatric cataract surgery is a significant postoperative complication that necessitates long-term surveillance. The IATS has defined glaucoma as an IOP of greater than 21 mmHg with at least one of the following: corneal enlargement, asymmetrical progressive myopic shift with an enlarged corneal diameter and/or axial length (AL), increased optic nerve cupping with a ratio of 0.2 or greater, or the use of a surgical procedure for IOP control. A patient is labeled as glaucoma suspect if there are two consecutive IOP measurements of greater than 21 mmHg without the use of topical corticosteroids and with no anatomical changes [15]. Glaucoma after pediatric cataract surgery is typically late-onset open-angle glaucoma and can often be diagnosed while patients are still asymptomatic.

To date, there is no universally accepted explanation for the etiology of glaucoma after pediatric cataract surgery. This condition may be due to damage of an eye that is still developing, and some studies have suggested that secondary glaucoma results from anterior chamber inflammation and damage to the under-developed iris and trabecular meshwork [9]. There have been numerous studies aimed at detecting risk

Complications of Pediatric Cataract Surgery

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Glaucoma and Transient Ocular Hypertension

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factors in patients predisposed to developing glaucoma. There has been much disagreement, but the age at surgery and age at diagnosis are the two most widely agreedupon factors. Previous studies have found that the risk of glaucoma decreases with increasing months of age at the time of cataract extraction [16]. Specifically, the odds of developing glaucoma are 1.6 times higher for each month of age younger at the time of cataract surgery. The highest risk is in infants with bilateral cataracts who have undergone cataract surgery at 4 weeks of age or younger [17]. Multivariate analysis of infants enrolled in the IATS has shown that only younger age at surgery increases the risk of developing glaucoma (by 3.2 times) [17].

Some studies have reported that the risk of developing postoperative glaucoma is decreased with primary IOL implantation [18–20]. We have reported that this appearance of protection may be merely a selection bias, with older and more developed eyes receiving IOLs and younger, less developed eyes being left aphakic [21]. Recently published randomized clinical trial results from the IATS for patients 5 years of age concur with our observations; glaucoma was reported in 9 (16%) eyes with contact lenses and in 11 (19%) eyes with primary IOL implantation [17].

Contradictory associations have been found between microphthalmia and glaucoma since age may be a confounding variable for corneal size. The IATS found that eyes with smaller corneal diameter (≤10 mm) at cataract removal were not at a higher risk of glaucoma within the 1 to <7 month age group [17]. These findings concur with our results published in 2006. In a retrospective study, we did not find a significant difference in pre-cataract surgery corneal diameter between eyes that developed postoperative glaucoma and those that did not [21].

Studies have also found that patients with some types of cataracts, specifically those with persistent fetal vasculature (fig. 2), are more likely to develop glaucoma because these cataracts directly result from problems with anterior chamber development.

The 5-year results of the IATS have recently identified patients with persistent fetal vasculature as having a 3.1-times higher risk of developing glaucoma [17].

Central corneal thickness should be measured during follow-up visits in children who have undergone surgery for cataract during infancy [22, 23]. Glaucoma is especially difficult to diagnose in children because it is harder to obtain IOP measurements and optic cup-to-disc ratios and to perform visual field tests. Previous studies have found that even in patients with asymptomatic secondary glaucoma with an onset of several years after surgery, diagnosis can be made within 1 year of surgery [24, 25].

Thus, it is particularly important to obtain regular IOP measurements in children after cataract surgery to stop disease progression before significant damage occurs. It is equally important to continue monitoring these patients for many years, as there may be a lifelong risk of developing secondary glaucoma. If reliable IOP measurements cannot be obtained in the clinic, then examinations under anesthesia should be conducted at yearly intervals [26]. Different anesthetics will variably affect IOP, but the AL is not affected by anesthetics and should be included in the standard evaluation for glaucoma. A rebound tonometer (Icare TAO1i; Icare USA, Raleigh, N.C., USA)

may be used as a clinical tool for children who cannot withstand the traditional examination for measuring IOP. When using this tonometer, it is not necessary to administer a topical anesthetic, which leads to increased compliance in children. This instrument facilitates more frequent clinical IOP measurements and thus fewer examinations under anesthesia.

Treatment for glaucoma should ideally be performed early and effectively to prevent ongoing damage to the eye. Treatment is typically topical medical management or surgery. Open-angle glaucoma treatment for pediatric aphakic patients is different than that for pediatric congenital glaucoma patients. While the initial treatment is usually surgery in congenital cases, the first line of treatment for glaucoma in aphakic and pseudophakic eyes is medical.

Timolol (0.25%) topical therapy is often the first-line medication used. This betaadrenergic antagonist reduces aqueous humor production and is well tolerated but should be avoided in children with asthma or a heart condition. Topical carbonic anhydrase inhibitors (CAIs), such as drozolamide 2%/Trusopt 1%/Azopt, also limit aqueous humor production. CAIs are used as the second-line treatment after beta-antagonists because they may produce systemic effects, such as tingling in the extremities, loss of energy, lack of appetite, and diarrhea. These side effects are most often observed when CAIs are used orally and are quite rare with the topical preparations. Topical agents are not as efficacious as oral agents but are safer. Phospholine iodide/echothiophate iodide 0.125% is also effective. This older and more difficult to get medication is rarely used in phakic patients because it may be associated with cataract formation. However, this is not a concern in aphakic or pseudophakic children and works well for managing pediatric secondary glaucoma [27]. Prostaglandin analogs, such as latanoprost 0.005%, travoprost 0.004%, and bimatoprost 0.03%, are used as a secondary or tertiary option in secondary glaucoma. Prostaglandins increase the outflow of aqueous humor but are less efficacious in aphakic or pseudophakic children compared to adults.

Aphakic patients who are refractory to medical management may need to undergo a surgical procedure, such as tube shunt implantation, trabeculectomy with mitomy-

Complications of Pediatric Cataract Surgery

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Fig. 2. Persistent fetal vasculature with stretched ciliary processes.

cin C, trabeculotomy, goniotomy, or one of the cyclodestructive procedures, to control IOP. Although such cases are rare, pseudophakes are more likely to develop closed-angle or pupillary block glaucoma. Surgical or laser iridectomy is the standard of care in these patients, and both of these procedures are followed by medical therapy in most cases.

Transient Ocular Hypertension A frequent complication of pediatric cataract surgery is increased IOP. A study conducted by the Childhood Cataract Program of the Chinese Ministry of Health found that IOP typically peaks at 1 week after surgery and remains elevated for an average of 30 days. In monocular cataract patients, ocular hypertension does not develop in the untreated fellow eye [28]. A possible explanation for the early postoperative spike in IOP is the retaining of a cohesive ophthalmic viscosurgical device, particularly in patients with glaucoma who are undergoing secondary IOL implantation [29]. Another explanation may be damage to the iris during surgery [7]. Postoperative topical steroids can also cause an increase in IOP, but this so-called ‘steroid response’ type of ocular hypertension usually subsides soon after discontinuation of topical steroids. Ultimately, increased IOP that is untreated or does not return to baseline can result in pain, corneal edema, and optic nerve damage. Increased IOP is seen more frequently in patients with aphakic glaucoma who are undergoing secondary IOL implantation. The IOP spike can be treated with topical or systemic glaucoma medications.

Retinal detachment is a rare and late complication of pediatric cataract surgery. Improvements in surgical techniques and advancements in technology, such as highspeed vitreous cutters, have helped to reduce the incidence of retinal detachment as a complication of cataract surgery. It will take decades to determine how much these new techniques and high-speed cutters reduce this incidence. In a recent long-term follow-up study of children from birth to 17 years of age who underwent cataract surgery, 1,043 eyes of 656 children were studied. Of them, 25 eyes in 23 children developed retinal detachment at an average of 9.1 years after surgery. This study calculated a 3% overall risk of retinal detachment in developmentally normal children with cataract and a 7% 20-year risk of retinal detachment. This risk increased to 16% if the patient had other ocular or systemic abnormalities [30] and increased further to 23% in children with mental retardation.

Eyes with traumatic cataract, ectopia lentis, and Stickler syndrome are at a higher risk of developing this complication. As retinal detachment may develop many years after surgery, long-term follow-up is warranted. Detailed retinal examinations are recommended after cataract surgery, performed at least yearly. This is especially im-

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Dev Ophthalmol. Basel, Karger, 2016, vol 57, pp 69–84 (DOI: 10.1159/000442502)

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Retinal Detachment

portant for those eyes at a higher risk of retinal detachment by virtue of a long AL for age, persistent fetal vasculature, diagnosis of a syndrome known to be associated with liquefaction of the vitreous, or multiple surgeries.

Endophthalmitis is one of the most severe complications that can occur following cataract surgery. Improved surgical conditions and early diagnosis has improved outcomes, but rates vary worldwide. Melo et al. reported an incidence rate of between 0.05 and 0.4% worldwide [31]. Wheeler, Stager, and Weakley reported a rate of 0.071% following pediatric intraocular surgery for cataracts and congenital glaucoma [32].

Bacteria from surgical instruments or the patient’s cornea or conjunctiva may be introduced into the eye during the perioperative period. The most common infectious organisms are Staphylococcus and Pseudomonas [33]. Staphylococcus species isolated from the vitreous of patients with endophthalmitis were most commonly recovered from the eyelids [34]. The Endophthalmitis Vitrectomy Study found that 9.9% of cases of culture-confirmed endophthalmitis were caused by S. aureus, 9.0% were caused by Streptococcus species, and 2.2% were caused by Enterococcus species. Seventy percent of all confirmed cases were caused by Gram-positive, coagulase-negative bacteria [35]. Additionally, the incidence of methicillin-resistant S. aureus infections is increasing [36].

Infectious microbes from patients’ endogenous flora are likely transferred to surgical instruments prior to invasion, particularly with corneal incisions [37]. Thus, surgeries requiring repeated insertion of instruments into the eye or reoperation (i.e. secondary IOL implantation) increase the risk of endophthalmitis. The infection risk has also been shown to higher when there is retained lens material or posterior capsule rupture with loss of vitreous [38]. Iris prolapse, rupture of the posterior capsule, and wound leaks all increase the risk of postoperative endophthalmitis. Thus, the removal of the posterior capsule in pediatric cataract surgery may lead to an increased risk compared to adult cataract surgery.

To reduce the risk of endophthalmitis, it is necessary to reduce the number of periocular microbes preoperatively and postoperatively. Prophylactic treatment for pediatric cataract surgery is similar to that for adult cataract surgery. Surgical disinfection and sterilization is necessary. Povidone-iodine is commonly used as a disinfectant prior to surgery to reduce the patient’s conjunctival and periocular endogenous flora [39, 40]. The preoperative topical, intraoperative infusion, intracameral, and postoperative subconjunctival routes are options for the delivery of antibacterial medications for increased ocular penetration. Cefuroxime, vancomycin, and moxifloxacin are commonly used intracamerally during cataract surgery [33, 36].

Recent studies of adults have reported a marked decrease in endophthalmitis when intracameral antibiotics are used. The use of intracameral antibiotics in either the ir-

Complications of Pediatric Cataract Surgery

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Endophthalmitis

rigating solution or injected postoperatively has been extensively tested in adults.

The number of pediatric cataract surgeons using intracameral antibiotics at the time of surgery is increasing worldwide as evidence mounts as to its effectiveness at lowering the rate of endophthalmitis. In the USA, the absence of an ophthalmic preparation specific for use for intracameral injection has slowed adoption of intracameral antibiotics for fear of toxicity caused by dilution errors during medication preparation.

The treatment of patients who contract infectious endophthalmitis includes administration of intravitreal antibiotics supplemented with systemic antibiotics. Systemic antibiotics cannot be used alone because anti-staphylococcal antibiotics do not have sufficient ocular penetration.

Toxic Anterior Segment Syndrome

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Toxic anterior segment syndrome (TASS) is acute, sterile inflammation of the anterior segment after cataract surgery, commonly due to contamination of surgical instruments or insertion of toxic substances into the eye. TASS occurs most frequently at 12â&#x20AC;&#x201C;72 h postoperatively. There is typically no pain or vitreous involvement, but decreased vision can occur due to tissue damage. Damage to the cornea results in corneal edema and fibrin formation. Ultimately, changes in pupil shape, glaucoma, and permanent dilation can occur but usually resolve spontaneously or with the use of nonsteroidal anti-inflammatory drugs [41].

A task force of the American Society of Cataract Refractive Surgery (ASCRS) has made a number of recommendations for the cleaning and sterilizing of intraocular surgical instruments, including the following [42]: (1) keep instruments moist until they are cleaned to avoid the drying of debris and viscoelastic agents on them; (2) rinse reusable instruments and cannulas with copious volumes of water, as specified by the manufacturer; (3) use disposable cannulas and tubing whenever possible; (4) do not reuse devices labeled for single use, and (5) do not use glutaraldehyde to sterilize intraocular instruments. These recommendations and their distribution have resulted in increased awareness of the causes of TASS and have resulted in a greater proportion of surgical centers implementing improved instrument flushing and rinsing protocols to reduce the risk of TASS [43]. It is imperative that pediatric ophthalmologists be familiar with the recommendations of the ASCRS Ad Hoc Task Force on Cleaning and Sterilization of Intraocular Instruments [44]. It may be helpful for pediatric ophthalmologists to provide formal instruction to the operating room and central processing staff at their own hospitals to ensure that these recommendations are being followed. This is especially important if pediatric ophthalmologists are performing surgery in an area where adult cataract surgeries are not performed.

Cornea

Corneal Edema Corneal edema is a common problem after cataract surgery. Recent studies have asserted that it is the most common complication occurring on the first postoperative day [4]. The edema may be localized or diffuse. Localized edema is due to trauma to the corneal endothelium and resulting inflammation, and diffuse edema causes increased IOP. Steroids may be used to treat inflammation and thus decrease pressure inside of the eye [41]. The IATS has described corneal edema as an adverse postoperative complication only if it persists for more than 30 days. This persistence was observed in only 1 of 57 eyes in the IOL group [45].

Contact Lens Problems It is not uncommon for problems to result from extended contact lens use in aphakic patients. Common problems are keratitis, corneal opacity, corneal vascularization, and corneal abrasion. Abrasions frequently result from difficulty with inserting or removing the contact lens [26]. The IATS study reported corneal abrasion in only 1 eye of the 57 patients in the contact lens group.

Other Corneal Complications Cataract surgery may also result in increased corneal thickness and corneal endothelial cell loss. Increased corneal thickness is due to surgical manipulation and incision, and the thickest areas are typically correlated with instrument incision points. Endothelial cell loss occurs after cataract surgery and is dependent upon the cataract type, AL, anterior chamber depth, and surgical factors. Cell loss is the greatest at 3 months after surgery. Endothelial cell loss is best measured with specular microscopy, and children receiving a secondary IOL, Artisan iris-claw IOL, or angle-supported anterior chamber IOL should be routinely measured [26].

Anterior Chamber

Fibrinous Uveitis Previous studies have asserted that fibrinous reaction due to increased uveal tissue reactivity in children is one of the most common postoperative complications following cataract surgery [7]. Most cases of fibrinous uveitis are diagnosed within 3

Complications of Pediatric Cataract Surgery

Nucci P (ed): Pediatric Cataract.

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Shallow Anterior Chamber A shallow anterior chamber may form postoperatively and is typically due to wound leakage from the patient rubbing the operated eye. The chamber may return to a normal depth naturally, but surgery is often necessary to reform the chamber and to free the iris from the wound. Re-suturing of the wound may be needed [26].

months of surgery, specifically within the first 2 weeks [5]. Surgical techniques that decrease iris and capsular bag manipulation decrease the likelihood of developing uveitis. Uveitis results in formation of fibrin membranes, pigment deposition and decentration of the IOL, posterior synechiae, and capsular blockage syndrome [9].

Topical and systemic steroids may decrease the inflammatory response prophylactically, while recombinant plasminogens may be used for treatment after fibrin formation has occurred [46]. Surgical procedures to treat fibrin deposition include YAG laser therapy, simple mechanical discission, and intraocular steroid delivery system implantation.

Hyphema Postoperative hyphema is rare but can occur, especially in eyes with persistent fetal vasculature.

Residual Triamcinolone Some surgeons use triamcinolone to identify residual vitreous strands and as an antiinflammatory agent. Although it disappears from the anterior chamber in most eyes within days after surgery, it may persist for a longer period of time, especially if it reaches the vitreous cavity.

Iris and Pupil

Abnormalities Due to Intraocular Lenses Corectopia and iris shape abnormalities most commonly result after anterior chamber IOL implantation. Corectopia is displacement of the pupil from the center of the eye and is most commonly associated with an updrawn pupil [47]. The IATS identified corectopia in 19% of pseudophakic eyes compared to only 2% of eyes that remained aphakic [45]. Iris erosion and atrophy may occur from iris manipulation or prolapse during surgery or from IOL malposition.

Posterior Synechiae Posterior synechiae occur when the iris adheres to the cornea as the result of an inflammatory response after ocular surgery. The risk of developing synechiae is largely dependent upon the amount of induced inflammation, in addition to age and the IOL type. A previous study has described the development of more synechiae with PMMA

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Prolapse Iris prolapse can occur during surgery since the pediatric iris is relatively floppy compared to the adult iris. Rarely, iris prolapse can occur after pediatric cataract surgery as a result of spontaneous wound leakage or postoperative trauma. A prolapsed iris may lead to anterior uveitis and endophthalmitis [41].

lenses than with AcrySof® acrylic lenses (19.2 vs. 4.5%, respectively) [48]. A recent study of children with chronic uveitis receiving preoperative anti-inflammatory medication reported that five of fourteen implanted eyes developed posterior synechiae following cataract surgery, while none of the six eyes that remained aphakic developed synechiae. This study went on to assert that eyes with chronic uveitis should remain aphakic to avoid posterior synechiae [49]. In most cases of posterior synechiae, there is no pupil shape abnormality, but the synechiae prevent full pupil dilation when pharmacologic dilating drops are placed on the eye.

Heterochromia Heterochromia is a color difference of one iris compared to the other due to varying amounts of prostaglandin. The amount of prostaglandin released determines the amount of pigment expressed, which leads to a darkened iris. Cataract surgery stimulates prostaglandin release, which can result in heterochromia, particularly when the surgery occurs in infancy. In previous studies, thirteen of fifteen pediatric patients examined after cataract surgery were found to have a significantly darker iris color in the operated eye compared to the unoperated fellow eye [50].

Intraocular Lens

Pupillary Capture Pupillary capture is more common in children than adults and frequently develops concomitantly with posterior synechiae and PCO. Pupillary capture can be prevented by placing the IOL in the capsular bag, rather than the ciliary sulcus, and assuring that the anterior capsulorhexis is round and smaller than the IOL optic. Although there are no vision changes, there may be cosmetic deformities. Persistent inflammation is rare. Thus, pupillary capture can remain untreated or can be surgically repaired to reshape the pupil and center the IOL [26].

Complications of Pediatric Cataract Surgery

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Deposits on Intraocular Lens Surface After cataract surgery, the eye’s inflammatory response may cause fibrinous reactions that lead to the formation of deposits on the surface of the IOL. These deposits may be pigmented or nonpigmented, but they do not cause visual obstruction unless they become confluent. Young patients with dark irises who are noncompliant are the most likely to develop deposits. Further, the likelihood of developing deposits may be influenced by the location of IOL implantation with sulcus-fixated IOLs and, in one study, optics captured through posterior continuous curvilinear capsulorhexis were found to develop the most deposits [51]. The type of IOL also contributes to deposit formation. Previous studies have found increased deposits on PMMA lenses compared to hydrophobic acrylic lenses (21.75 vs. 6.4%, respectively) [48]. Deposits are most commonly observed at 3 months postoperatively [52].

Intraocular Lens Positional Problems Malposition, decentration, and dislocation of the IOL may occur after cataract surgery due to capsular fibrosis, asymmetric fixation, inadequate capsular support, or loss of a portion of the zonule due to trauma. Of these causes, capsular fibrosis and asymmetric IOL fixation are the most common [26]. Posterior capture of the IOL optic may also result in better centration of the implanted IOL [51]. A recent study found decentration in 4.6% of patients. None were visually significant and none required reoperation [7]. However, in extreme cases, the IOL may need to be repositioned or exchanged.

Glistenings Within the Intraocular Lens Glistenings are a common finding postoperatively with slit lamp examination with some hydrophobic acrylic IOLs. Most frequently, glistenings occur with implanted single-piece AcrySof® IOLs as early as 1 week after surgery. The degree of glistening increases over the next 2 years, after which it stabilizes. It is likely visually insignificant; however, it may have some as yet unproven deleterious effects on the developing eyes of children [26].

Opacification of Foldable Intraocular Lenses Late postoperative opacification of some specific models of hydrophilic IOLs in adults has been reported widely in the literature. In these patients, the opacification was severe enough to require the IOL to be explanted. The majority of reports concern adult cases from Asia, Australia, Canada, Europe, Latin America, and South Africa. One report included opacification of hydrophilic acrylic IOLs in children and suggested that there may be a special pattern of dystrophic calcification in this population [53]. Kleinmann et al. [53] reported the clinicopathological and ultrastructural features of three hydrophilic acrylic IOLs manufactured from two different biomaterials, explanted from children who had visual disturbances caused by progressive postoperative opacification of the lenses’ optic components. These lenses were explanted at 20, 22, and 25 months postoperatively in children who were aged 10, 36, and 20 months, respectively, at the time of lens implantation. Pehere et al. [54] reported that the deposits were found to be composed of calcium, phosphate, and silicone.

Anterior Capsule Fibrosis and Phimosis

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Excessive fibrosis of the anterior capsule can reduce the size of the anterior capsule opening, causing problems during examination of the retina. It may also cause decentration of the IOL.

Hemorrhagic Retinopathy

Hemorrhagic retinopathy occurs in up to one-third of infants after cataract extraction. Flame-shaped retinal hemorrhages associated with vitreous hemorrhage occur on the first postoperative day. They are self-limited and do not result in lasting complications [26].

Cystoid Macular Edema

Cystoid macular edema (CME) occurs much more rarely in children than in adults.

CME is particularly hard to diagnose in pediatric patients due to the increased difficulties with performing macular examination and ocular coherence tomography scan on children. Thus, it is rarely diagnosed in children. Studies that have attempted to measure CME incidence in children have reported significantly lower rates than in adults. This may be attributed to a more resistant anterior segment, healthy retinal vasculature, and altered vitreous consistency [55]. The incidence of CME as these children grow older is not well known. If a child does develop this condition, then it should be treated with topical corticosteroids and nonsteroidal anti-inflammatory medications.

Ptosis

Postoperative ptosis is another problem that may occur after cataract surgery. Surgery of the eyelid is rarely required.

Hypotony

Postoperative hypotony, defined as lower than normal IOP, can occur after pediatric cataract surgery. While early hypotony is likely due to wound leakage or ciliary body shutdown as a result of postoperative uveitis, continued hypotony may indicate postoperative retinal detachment, phthisis bulbi, or choroidal effusions. Postoperative hypotony is usually self-limited [26].

Phthisis bulbi, or a scarred, shrunken globe, may occur postoperatively from chronic retinal detachment or chronic hypotony or after endophthalmitis. The IATS reported phthisis bulbi in one of fifty-seven aphakic eyes [45] as a sequela of endophthalmitis.

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Phthisis Bulbi

A recent study reported the presence of phthisis bulbi in 2.7% of twenty pediatric patients with severe microphthalmos (an AL of 16.5 mm or less) and visually significant cataract without an IOL implant [56].

Refractive Error

Astigmatism Astigmatism commonly occurs in pediatric patients following cataract surgery and may increase the risk of amblyopia. The development of astigmatism is due to sutures placed to ensure for proper wound healing. Much of this suture-induced astigmatism regresses over time as the wounds heal and sutures dissolve, loosen or are removed. Some surgeons prefer a scleral tunnel or a temporal incision site to decrease induced astigmatism [9].

Myopic Shift Myopia is common after cataract surgery. It can be treated using contact lenses, glasses, primary IOL exchange, secondary piggyback IOL implantation or corneal refractive surgery.

Conclusions

Complications in children after cataract surgery are numerous and can occur for years postoperatively. It is important to monitor pediatric patients to prevent or treat complications and to ensure for appropriate vision development.

Acknowledgment This work was supported in part by Research to Prevent Blindness, New York, N.Y., USA.

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