Update of intraocular lens implantation in children

Incidence and predisposing factors of intraocular Lens tilt following secondary ciliary sulcus implantation in children: An ultrasound biomicroscopic study

PURPOSE

To evaluate the incidence and causes of intraocular lens (IOL) tilt and changes in anterior chamber angle after secondary IOL sulcus implantation following congenital cataract removal.

METHODS

A retrospective observational study was conducted on children who underwent secondary sulcus IOL implantation following pediatric cataract removal in the period from 2017-2020 in Cairo university Hospitals. Children were examined for IOL position, centration, and tilt. Intraocular pressure (IOP) measurement, fundus and gonioscopic examination was performed. Ultrasound biomicroscopy (UBM) was performed on both eyes in children with clinically detected tilt.

RESULTS

Ciliary sulcus secondary IOL implantation was performed in 102 eyes (57 children). IOL tilt was detected clinically in 16 eyes of 14 children (15.7%). UBM showed clinically undetected tilt in the fellow eye in additional 4 eyes. The mean angle of tilt was 12.8 ± 3.9° in clinically detected tilt compared to 7.5 ± 1.2° in UBM detected tilt. Mean anterior chamber depth (ACD) was 2.4 ± 0.5 mm IOP was >21 mmHg in 1.9% of eyes. Narrowing of the anterior chamber angle (ACA) after sulcus implantation occurred in 40% of eyes with open angle. Sulcus proliferations and obliterated sulcus were detected in all 20 eyes. Sommering's ring was found in 7 eyes (35%). Axial length, corneal diameter, and presence of persistent fetal vasculature did not affect IOL position.

CONCLUSION

The presence of residual lens matter or an obliterated ciliary sulcus is associated with a higher incidence of IOL malposition following ciliary sulcus implantation.

Posterior Capsulotomy Size Affects the Formation of Significant Visual Axis Opacification in Congenital and Developmental Cataract

PURPOSE

To assess the relationship between posterior capsulotomy size and significant visual axis opacification (VAO) in congenital and developmental cataract.

METHODS

The charts of children aged 7 years and younger who underwent cataract surgery including primary posterior capsulotomy (PPC) and limited anterior vitrectomy between 2012 and 2022 were retrospectively reviewed. Eyes with PPC size smaller than the anterior capsulotomy size were considered as group 1. Eyes with PPC size larger than the anterior capsulotomy size were considered as group 2. Clinical characteristics, the need for Nd:YAG laser treatment or further surgery for significant VAO, and other postoperative complications were compared between the groups.

RESULTS

Sixty eyes of 41 children were included in the study. The median age at the time of surgery was 5.5 and 3 years in groups 1 and 2, respectively (P = .076). Primary intraocular lens implantation was performed in 23 (85.2%) eyes in group 1 and 25 (75.8%) eyes in group 2 (P = .364). There was no difference between the groups in terms of postoperative visual acuity (P = .983) and refractive errors (P = .154). Eight (29.6%) pseudophakic eyes received Nd:YAG laser treatment in group 1, but none of the eyes in group 2 (P = .001). Four (14.8%) eyes in group 1 and 1 (3%) eye in group 2 underwent further surgery for VAO (P = .100). The need for further intervention for significant VAO was statistically higher in group 1 (44.4% vs 3%, P < .001).

CONCLUSIONS

Larger PPC size in pediatric cataract may reduce the need for further intervention for significant VAO. [J Pediatr Ophthalmol Strabismus. 2023;60(6):441-447.].

Secondary Intraocular Lens Implantation (IOL) in Children- What, Why, When, and How?

PURPOSE

To provide a comprehensive review on secondary IOL implantation in children who have undergone primary surgery at an early age and are aphakic aiming at answering common dilemmas among pediatric ophthalmologists.

METHOD OF LITERATURE REVIEW

A systematic literature search was done using keywords like secondary intraocular implantation, congenital cataractand surgical aphakia. Various novel case reports, retrospective case studies and review articles covering different aspects of secondary IOL implantation were searched and reviewed using PubMed and Google scholar journal search engines.

RESULTS

This article highlights various aspects of secondary IOL implantation like the appropriate timing should be when the child is entering preschool, with the proper technique being in bag fixation is the most preferred method with least associated complications and the IOL type should be decided based on the fixation site.

CONCLUSION

Secondary IOL implantation can accomplish good and stable long-term outcomes in children. It is the most accepted mode of optical correction once the appropriate age is achieved.

Accuracy of the SRK/T Formula in Pediatric Cataract Surgery

PURPOSE

Determining IOL power is an important step in achieving the desired postoperative refractive target, but this determination remains challenging, as currently the used formulas were developed using IOL power calculations derived from adults.

PATIENTS AND METHODS

This is a retrospective analytical study with the period of June 2018 to May 2019. All of the data were taken from medical records in referral tertiary eye hospital in Indonesia. All type of cataracts underwent uncomplicated surgeries and in-the-bag IOL implantation were included in this study, while aphakia, secondary IOL implantation, primary sulcus implantation, and history of ocular disorders were excluded. The data were analyzed using Wilcoxon sign-rank, paired t, and Kruskal-Wallis tests.

RESULTS

Sixty-seven patients (106 eyes) were found to meet the inclusion criteria, average age was 7.35 ± 4.61 years (1.00 to 17.00 years). Average targeted refraction was 1.69 ± 2.06 D (-0.38-+6.99 D), and spherical equivalent (actual postoperative refraction) was -0.90 ± 1.45 D (-4.38 to +2.75 D). There was statistically significant difference between preoperative targeted refraction and actual postoperative refraction (p < 0.001). Mean absolute prediction error (APE) in general was 1.34 ± 1.18 D, 1.22 ± 0.88 D (in short eyes), 1.52 ± 1.37 D (in moderate eyes), and 0.69 ± 0.52 D (in long eyes) (p = 0.202). Mean APE in age group <7 years old was 1.27 ± 1.18 D and ≥7 years-old was 1.42 ± 1.19 D (p = 0.429).

CONCLUSION

SRK/T formula is fairly accurate in calculating IOL power in pediatric cataract surgery. Mean APE in this study was within the range of accurate mean APE in pediatric patients despite differentiated axial length and age.

Accuracy of Intraocular Lens Power Calculation in Pediatric Secondary Implantation: In-the-Bag Versus Sulcus Placement

PURPOSE

To compare the effects of secondary in-the-bag vs ciliary sulcus intraocular lens (IOL) implantation on the accuracy of IOL power calculation in pediatric eyes.

DESIGN

Prospective nonrandomized interventional study.

METHODS

Pediatric aphakic eyes that underwent either in-the-bag or ciliary sulcus secondary IOL implantation were included. The mean prediction error (PE), mean absolute error (MAE), median absolute error, and percentages of eyes with PE within ±0.25 diopter (D), ±0.50 D, ±0.75 D, and ±1.00 D were calculated and compared using SRK/T formula.

RESULTS

One hundred fourteen eyes (38.26%) received in-the-bag IOL implantation and 184 (61.74%) underwent ciliary sulcus IOL implantation. Compared with the sulcus group, the capsular group displayed significantly lower MAE and higher percentage of eyes within ±0.50 D of PE (MAE: 0.90 vs 1.56 D; ±0.50 D: 40.40% vs 14.29%, both P < .001). The eyes receiving in-the-bag IOL implantation (sulcus IOL implantation β: -1.060, 95% CI: -1.415 to -0.705; P < .001), unilateral (β: 0.647, 95% CI: 0.144-1.150; P = .012), or with deeper anterior chamber depth (β: 0.362, 95% CI: 0.068-0.656; P = .016) were prone to maintain hyperopia (PE > 0). To reduce PE, when the predicted capsular IOL power was between 11.50 and 30.00 D, the power of a sulcus-implanted IOL should be reduced by 0.50 to 2.50 D accordingly (the exact amount of reduction is positively related to the predicted power).

CONCLUSIONS

In-the-bag implantation yielded smaller PE in pediatric eyes undergoing secondary IOL implantation. Adjustment of IOL power for ciliary sulcus implantation is required to reduce PE, and the amount of adjustment is positively correlated with the IOL power predicted by SRK/T formula.

Ocular biometric changes following unilateral cataract surgery in children

Purpose

To analyze ocular biometric changes following unilateral cataract surgery in children.

Methods

A total of 57 children aged under 13 years who underwent unilateral cataract surgery were analyzed. Groups were classified according to their age at surgery: group I (age <3), II (3≤ age <6), III (6≤ age <9), and IV (age ≥9). The myopic shift, axial growth, and corneal curvature changes were compared between the pseudophakic eyes and the fellow phakic eyes.

Results

During 7.81 ± 4.39 years, the overall myopic shift (D) and the rate of myopic shift (D/year) were significantly higher at -3.25 ± 3.21 D and -0.45 ± 0.44 D/year in the pseudophakic eyes than -1.78 ± 2.10 D and -0.22 ± 0.29 D/year in the fellow phakic eyes (P = 0.01, 0.004). Group I (-1.14 ± 0.66 vs -0.02 ± 0.45 D/year) and group II (-0.63 ± 0.37 vs -0.31 ± 0.29 D/year) showed significantly higher rate of myopic shift in the pseudophakic eyes than in the phakic eyes. The rate of myopic shift in the pseudophakic eyes decreased in the older age groups (P = 0.001). There was no significant between-eye difference in the changes in axial length and keratometric values postoperatively.

Conclusion

Following unilateral cataract surgery, a significant postoperative myopic shift was noticed in the pseudophakic eyes compared to the fellow phakic eyes in groups under 6 years old. Postoperative myopic shift and the resultant anisometropia should be considered when selecting the optimal power of IOL in young children requiring unilateral cataract surgery.

Bilateral cataract in a child with blepharophimosis-ptosis-epicanthus inversus syndrome: A surgical challenge

Introduction

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is a rare autosomal dominant genetic disorder characterized by complex orbito-palpebral anomalies. We report a rare case of BPES associated with bilateral congenital cataract.

Observation

This study reports the case of a 6-month-old infant with BPES in whom a bilateral congenital cataract was diagnosed, after the parents noticed leukocoria and signs of poor vision in their child. No other ophthalmologic manifestations commonly associated with this syndrome were found. The infant underwent cataract surgery first, with lens phacoaspiration and posterior capsulotomy coupled with anterior vitrectomy and placement of a 3-piece foldable hydrophobic posterior chamber lens in the capsular bag. The surgery was a real challenge due to the orbito-palpebral anomalies that limited a small surgical space, and the placement of the IOL was a matter of discussion.

Discussion

Publications on the association of congenital cataract with BPES are very rare. The link between these two anomalies is difficult to establish since different genes on different chromosomes code for the two diseases. A lateral canthotomy can be considered to overcome the surgical difficulties due to the reduced working space. The surgical management of pediatric cataract varies in the literature.

Conclusion

This case highlights the difficulty of cataract surgery in children, even more so when associated with BPES, and the challenge of improving vision in these children given the high risk of amblyopia.

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Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is a rare autosomal dominant genetic disorder. It characterized by complex orbito-palpebral anomalies.

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Association with a cataract constitutes a rare clinical form thus making the surgery of this cataract a callenge even for the most experienced surgeons.

Self-Induced Bilateral Retinal Detachments and Traumatic Cataracts in a Patient With Bohring-Opitz Syndrome

A 9-year-old female with a history of Bohring-Opitz syndrome (BOS), Down syndrome, and autism initially presented with bilateral cataracts and a total retinal detachment in her left eye secondary to chronic self-injurious behavior. The authors report the first case of self-induced retinal detachment and traumatic cataracts in a patient with BOS. For patients who present with self-injurious behavior, the authors advocate for behavioral modifications at home, including the use of "no-no's," supplemental medication if necessary, and behavioral therapy to reduce the risk of self-induced visual injury. The authors also suggest the use of 25-gauge vitrectomy with silicone oil for retinal detachment repair. Finally, given the high risk of irreversible vision loss from amblyopia and recurrent retinal detachments in children with BOS and self-injurious behavior, the authors recommend regular 2-month interval ophthalmic follow-up. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:400-402.].

A-scan biometry, phacoemulsification, and foldable intraocular lens implantation in a young orangutan (Pongo pygmaeus)

Background:

Cataracts are the major cause of visual impairment in animals which can be curable by surgical treatment. Phacoemulsification is the standard technique for cataract treatment that is applied to almost all species with a high success rate.

Case Description:

A 2-year-old intact female orangutan (Pongo pygmaeus) was presented for the study having bilateral opacity of the lenses, for 2 weeks. Ophthalmic examination revealed mature cataract OU. Ocular biometry measurements using A-scan ultrasonography for appropriate intraocular lens (IOL) refractive power calculation were carried out. Electroretinography was applied to ensure retinal function is intact. The orangutan underwent phacoemulsification OU and +24 diopter IOL implantation OS to restore vision. IOL implantation was not carried out OD because of a posterior capsular tear. Retinoscopy after 3 weeks postoperatively revealed +2.0 diopters OS. The outcome of the cataract surgery was successful during 3 years follow-up. The orangutan lived with other orangutans and was alert with normal behavior such as catching food, climbing trees, and swinging hand over hand from one branch to another.

Conclusion:

Cataract surgery with phacoemulsification OU and adjusted IOL implantation OD was successful with few complications in this orangutan. Vision was restored with normal behavior, even though an adjusted IOL was inserted in only one eye.

[Factors influencing target refraction in children with pseudophakia after extraction of congenital cataract]

The article describes the factors affecting the target refraction of pseudophakic eyes of children after extraction of congenital cataracts. The factors include features of the echobiometric parameters of the eye, refraction, comorbidity of congenital cataracts and ocular pathologies, margins of error in calculating strength of the intraocular lens, localization and structure of the artificial lens, as well as correction of obscure or refractive amblyopia in pseudophakic eyes. Development of the algorithm for correction of residual refraction of pseudophakic eyes in children both before and after IOL implantation with consideration of each of those factors currently remains a relevant problem.

Updates on managements of pediatric cataract

Purpose

A comprehensive review in congenital cataract management can guide general ophthalmologists in managing such a difficult situation which remains a significant cause of preventable childhood blindness. This review will focus on surgical management, postoperative complications, and intraocular lens (IOL)-related controversies.

Methods

Electrical records of PubMed, Medline, Google Scholar, and Web of Science from January 1980 to August 2017 were explored using a combination of keywords: "Congenital", "Pediatric", "Childhood", "Cataract", "Lens opacity", "Management", "Surgery", "Complication", "Visual rehabilitation”, and "Lensectomy". A total number of 109 articles were selected for the review process.

Results

This review article suggests that lens opacity obscuring the red reflex in preverbal children and visual acuity of less than 20/40 is an absolute indication for lens aspiration. For significant lens opacity that leads to a considerable risk of amblyopia, cataract surgery is recommended at 6 weeks of age for unilateral cataract and between 6 and 8 weeks of age for bilateral cases. The recommended approach in operation is lens aspiration via vitrector and posterior capsulotomy and anterior vitrectomy in children younger than six years, and IOL implantation could be considered in patients older than one year. Most articles suggested hydrophobic foldable acrylic posterior chamber intraocular lens (PCIOL) for pediatrics because of lower postoperative inflammation. Regarding the continuous ocular growth and biometric changes in pediatric patients, under correction of IOL power based on the child's age is an acceptable approach. Considering the effects of early and late postoperative complications on the visual outcome, timely detection, and management are of a pivotal importance. In the end, the main parts of post-operation visual rehabilitation are a refractive correction, treatment of concomitant amblyopia, and bifocal correction for children in school age.

Conclusions

The management of congenital cataracts stands to challenge for most surgeons because of visual development and ocular growth. Children undergoing cataract surgery must be followed lifelong for proper management of early and late postoperative complications. IOL implantation for infants less than 1 year is not recommended, and IOL insertion for children older than 2 years with sufficient capsular support is advised.

Long-term outcomes of intended undercorrection intraocular lens implantation in pediatric cataract

Purpose

To evaluate the postoperative refraction of intended undercorrection after intraocular lens (IOL) implantation in pediatric cataract patients.

Design

A cross-sectional study (data collected by retrospective chart review).

Patients and methods

The medical records of children aged under 10 years, who underwent cataract surgery with IOL implantation at the Ramathibodi Hospital between January 2000 and May 2018, were reviewed. IOL power calculations were 30%, 25%, 20%, 15% and 10% under-corrected if children were aged 6–12, 13–24, 25–36, 37–48 and 49–60 months, respectively. Two diopters (D) undercorrection was used in children aged between 5 and 8 years and one diopter undercorrection was used in children aged between 8 and 10 years. The main outcome measure was the postoperative refractive errors at the last follow-up visit.

Results

In total, 50 children (21 females and 29 males, 16 unilateral and 34 bilateral, 84 eyes) met the inclusion criteria for this study. Mean age at the time of surgery was 77.82±31.24 months. Mean follow-up time was 56.56±45.83 months. The main outcome in this study was the postoperative refractive error in children aged 7 years or more. We found 74 eyes of 44 children who were aged 7 years or more at last follow-up visit. In total, 45 eyes were myopic (−0.25 to −8.25 D) with a mean refraction of −2.26±2.16 D. A further 21 eyes were hyperopic (+0.25 to +3.25 D), with a mean refraction of +1.05±0.79 D and eight eyes were emmetropic or having only astigmatism.

Conclusion

The major postoperative refractive error at the last follow-up time was myopia. We have to adjust the IOL calculation formula to specify more undercorrection, with the aim of achieving more optimal refractive outcomes in adulthood.

Cataract as Early Ocular Complication in Children and Adolescents with Type 1 Diabetes Mellitus

Cataract is a rare manifestation of ocular complication at an early phase of T1DM in the pediatric population. The pathophysiological mechanism of early diabetic cataract has not been fully understood; however, there are many theories about the possible etiology including osmotic damage, polyol pathway, and oxidative stress. The prevalence of early diabetic cataract in the population varies between 0.7 and 3.4% of children and adolescents with T1DM. The occurrence of diabetic cataract in most pediatric patients is the first sign of T1DM or occurs within 6 months of diagnosis of T1DM. Today, there are many experimental therapies for the treatment of diabetic cataract, but cataract surgery continues to be a gold standard in the treatment of diabetic cataract. Since the cataract is the leading cause of visual impairment in patients with T1DM, diabetic cataract requires an initial screening as well as continuous surveillance as a measure of prevention and this should be included in the guidelines of pediatric diabetes societies.

Management of cataracts and ectopia lentis in children: Practice patterns of pediatric ophthalmologists in India

Purpose:

To analyze the current practice patterns of Indian pediatric ophthalmologists in the management of lens anomalies. This study was conducted in a tertiary eye care hospital and involved an online questionnaire survey for practicing pediatric ophthalmologists in India.

Methods:

A questionnaire was devised by the authors, which included the various options available for the management of lens anomalies in children. The questionnaire was sent to each of them using an online portal. Commercial software (Stata ver. 13.1; StataCorp, College Station, TX, USA) was used for statistical analysis.

Results:

In unilateral cataracts in children aged <6 months, 85.42% of surgeons did not prefer to insert an intraocular lens (IOL). In the age group of 6–12 months, almost half of them preferred to insert an IOL. In the age group of 12–24 months and >24 months, 92.63% and 88.54%, respectively, preferred to insert an IOL. In bilateral cataracts, in children aged <6 months, 91.84% of surgeons did not prefer to insert an IOL, whereas in the age group of 6–12 months, 69.39% did not prefer to insert an IOL. In the age group of 12–24 months and >24 months, 80.61% and 90.82%, respectively, preferred to insert an IOL. Seventy-four percent of surgeons preferred to use a single-piece hydrophobic acrylic IOL.

Conclusion:

The management of lens anomalies by pediatric ophthalmologists in India varies with laterality and appears to be comparable to that followed worldwide.

Screening, genetics, risk factors, and treatment of neonatal cataracts

Neonatal cataracts remain the most common cause of visual loss in children worldwide and have diverse, often unknown, etiologies. This review summarizes current knowledge about the detection, treatment, genetics, risk factors, and molecular mechanisms of congenital cataracts. We emphasize significant progress and topics requiring further study in both clinical cataract therapy and basic lens research. Advances in genetic screening and surgical technologies have improved the diagnosis, management, and visual outcomes of affected children. For example, mutations in lens crystallins and membrane/cytoskeletal components that commonly underlie genetically inherited cataracts are now known. However, many questions still remain regarding the causes, progression, and pathology of neonatal cataracts. Further investigations are also required to improve diagnostic criteria for determining the timing of appropriate interventions, such as the implantation of intraocular lenses and postoperative management strategies, to ensure safety and predictable visual outcomes for children. Birth Defects Research 109:734-743, 2017. © 2017 Wiley Periodicals, Inc.

Strabismus developing after unilateral and bilateral cataract surgery in children

PurposeTo evaluate the prevalence and risk factors of strabismus in children undergoing surgery for unilateral or bilateral cataract with or without intraocular lens implantation.MethodsMedical records of pediatric patients were evaluated from 2000 to 2011. Children undergoing surgery for unilateral or bilateral cataract with at least 1 year of follow-up were included. Children with ocular trauma, prematurity, or co-existing systemic disorders were excluded. The following data were evaluated: strabismus pre- and post-operation; age at surgery; post-operative aphakia or pseudophakia; and visual acuity.ResultsNinety patients were included, 40% had unilateral and 60% had bilateral cataracts. Follow-up was on average 51 months (range: 12-130 months). Strabismus was found preoperatively in 34.4% children, and in 43.3% children at last follow-up. Strabismus developed in 46.2% of children who were orthotropic preoperatively, whereas 32.3% of children who had strabismus before surgery became orthotropic. Strabismus occurred after unilateral or bilateral cataract surgery in 63.9% and 29.6% children, respectively. At the last follow-up, strabismus was found in 46.7% of aphakic and 58.7% of pseudophakic children (P=0.283). Children who developed strabismus were generally operated at a younger age as compared with those without strabismus (mean of 25.9 vs 52.7 months, P<0.001). Final visual acuity was inversely correlated with prevalence of strabismus.ConclusionStrabismus is a frequent complication after cataract surgery in children. Risk factors include unilateral cases and young age at surgery. No correlation was found between prevalence of strabismus and use of intraocular lens. Strabismus was more common in children with poor final visual acuity.

Evaluation of a Public Child Eye Health Tertiary Facility for Pediatric Cataract in Southern Nigeria I: Visual Acuity Outcome

Purpose:

A retrospective study of the outcome of congenital and developmental cataract surgery was conducted in a public child eye health tertiary facility in children <16 years of age in Southern Nigeria, as part of an evaluation.

Materials and Method:

Manual Small Incision Cataract Surgery with or without anterior vitrectomy was performed. The outcome measures were visual acuity (VA) and change (gain) in visual acuity. The age of the child at onset, duration of delay in presentation, ocular co-morbidity, non ocular co-morbidity, gender, and pre operative visual acuity were matched with postoperative visual acuity. A total of 66 children were studied for a period of six weeks following surgery.

Results:

Forty eight (72.7%) children had bilateral congenital cataracts and 18 (27.3%) children had bilateral developmental cataracts. There were 38(57.6%) males and 28 (42.4%) females in the study. Thirty Five (53%) children had good visual outcome (normal vision range 6/6/ -6/18) post-operatively. The number of children with blindness (vision <3/60) decreased from 61 (92.4%) pre-operatively to 4 (6.1%) post-operatively. Post operative complication occurred in 6.8% of cases six week after surgery. Delayed presentation had an inverse relationship with change (gain) in visual acuity (r = - 0.342; p-value = 0.005). Pre-operative visual acuity had a positive relationship with post operative change (gain) in visual acuity (r = 0.618; p-value = 0.000).

Conclusion:

Predictors of change in visual acuity in our study were; delayed presentation and pre-operative VA. Cataract surgery in children showed clinical benefit.

Optical correction of aphakia in children

There are several reasons for which the correction of aphakia differs between children and adults. First, a child's eye is still growing during the first few years of life and during early childhood, the refractive elements of the eye undergo radical changes. Second, the immature visual system in young children puts them at risk of developing amblyopia if visual input is defocused or unequal between the two eyes. Third, the incidence of many complications, in which certain risks are acceptable in adults, is unacceptable in children. The optical correction of aphakia in children has changed dramatically however, accurate optical rehabilitation and postoperative supervision in pediatric cases is more difficult than adults. Treatment and optical rehabilitation in pediatric aphakic patients remains a challenge for ophthalmologists. The aim of this review is to cover issues regarding optical correction of pediatric aphakia in children; kinds of optical correction , indications, timing of intraocular lens (IOL) implantation, types of IOLs, site of implantation, IOL power calculations and selection, complications of IOL implantation in pediatric patients and finally to determine the preferred choice of optical correction. However treatment of pediatric aphakia is one step on the long road to visual rehabilitation, not the end of the journey.