Myopic shift after cataract removal in childhood

Refractive Growth of the Crystalline Lens in the Infant Aphakia Treatment Study

Objective

To compare the rate of refractive growth (RRG3) of the crystalline lens ("lens") versus the eye excluding the lens ("globe") for the fellow, noncataractous eyes of participants in the Infant Aphakia Treatment Study.

Design

Retrospective cohort study.

Subjects

A total of 114 children who had unilateral cataract surgery as infants were recruited. Biometric and refraction data were obtained from the normal eyes at surgery and at 1, 5, and 10 years. Subjects were included if complete data (axial length [AL], corneal power, and refraction) were available at surgery and at 10 years of age.

Methods

At surgery and at 1, 5, and 10 years, AL, corneal power, and cycloplegic refraction were measured in the normal eyes. For each eye, the RRG3 was defined by linear regression of refraction at the intraocular lens (IOL) plane against log₁₀ (age + 0.6 years). The RRG3 for the globe was based on IOL power for emmetropia; the RRG3 for the lens was based on IOL power calculated to give the observed refractions. Intraocular lens powers were calculated with the Holladay 1 formula. The means were compared with a paired 2-tailed t test, and linear regression was used to look for a correlation between RRG3 of the lens globe.

Main Outcome Measures

The RRG3 of the lens and globe.

Results

Complete data were available for 107 normal eyes. The mean RRG3 of the lenses was -12.0 ± 2.5 diopters (D) and the mean RRG3 of the globes was -14.1 ± 2.7 D (P < 0.001). The RRG3 of the lens correlated with the RRG3 of the globe (R ²  = 0.25, P < 0.001).

Conclusions

The RRG3 was 2 D more negative in globes compared with lenses in normal eyes. Globes with a greater rate of growth tended to have lenses with a greater rate of growth.

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.

Deviations From Age-Adjusted Normative Biometry Measures in Children Undergoing Cataract Surgery: Implications for Postoperative Target Refraction and IOL Power Selection

PURPOSE

To evaluate whether pediatric eyes that deviate from age-adjusted normative biometry parameters predict variation in myopic shift after cataract surgery.

METHODS

This is a single institution longitudinal cohort study combining prospectively collected biometry data from normal eyes of children <10 years old with biometry data from eyes undergoing cataract surgery. Refractive data from patients with a minimum of 5 visits over ≥5 years of follow-up were used to calculate myopic shift and rate of refractive growth. Cataractous eyes that deviated from the middle quartiles of the age-adjusted normative values for axial length and keratometry were studied for variation in myopic shift and rate of refractive growth to 5 years and last follow-up visit. Multivariable analysis was performed to determine the association between myopic shift and rate of refractive growth and factors of age, sex, laterality, keratometry, axial length, intraocular lens power, and follow-up length.

RESULTS

Normative values were derived from 100 eyes; there were 162 eyes in the cataract group with a median follow-up of 9.6 years (interquartile range: 7.3-12.2 years). The mean myopic shift ranged from 5.5 D (interquartile range: 6.3-3.5 D) for 0- to 2-year-olds to 1.0 D (interquartile range: 1.5-0.6 D) for 8- to 10-year-olds. Multivariable analysis showed that more myopic shift was associated with younger age (P < .001), lower keratometry (P = .01), and male gender (P = .027); greater rate of refractive growth was only associated with lower keratometry measures (P = .001).

CONCLUSIONS

Age-based tables for intraocular lens power selection are useful, and modest adjustments can be considered for eyes with lower keratometry values than expected for age.

Congenital cataract surgery: long-term refractive outcomes of a new intraocular lens power correction formula

PURPOSE

The final refraction after intraocular lens (IOL) implantation remains a challenge in the management of paediatric cataracts. No consensual guidelines exist for the choice of IOL power. The aim of this study was to validate a method of IOL power calculation by evaluating the final refractive error in all patients with IOL implantation operated at our institution.

METHODS

We retrospectively studied all children under 7 years of age who underwent cataract surgery with IOL implantation at our institution between 2010 and 2015. Intraocular lens (IOL) power was calculated as follows: After B-scan determination of the emmetropic IOL power, a reduction of 40%, 35%, 30%, 25%, 20%, 15%, 10% and 5% was applied to children 0-3, 3-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-48 months, respectively. The following data were collected: follow-up, age at surgery, uni- or bilaterality, implanted IOL power and final refraction.

RESULTS

During this period, 81 children (125 eyes) met the inclusion criteria with a median follow-up of 60 months (36-97). The median age at surgery was 6.61 months (0.76-48). We included 52 children with bilateral cataract (96 eyes) and 29 children with unilateral cataract (29 eyes). The mean implanted IOL power was 23.3 ± 4.6 diopters (D). The mean spherical equivalent at last follow-up was 0.07 ± 3.5 D.

CONCLUSION

Our undercorrection formula for IOL implantation after congenital cataract surgery leads to long-term refractive results globally close to emmetropia.

Cataract in retinopathy of prematurity - A review

Preterm babies with retinopathy of prematurity (ROP) can become blind if they do not receive appropriate timely intervention. The presence of cataract in these individuals in addition to visual deprivation amblyopia, also delays proper screening, adequate treatment, and makes follow-up assessment difficult. Anatomical differences in these infants and amblyopia management, especially in unilateral cataract, are other important concerns, and hence, management of these cases with cataract and ROP is challenging. In this review, studies where ROP cases were associated with cataract, were evaluated with a focus on preterm individuals less than 6 months age. Preterm babies are at increased risk of developing cataract because of systemic factors. In addition, those with ROP may have cataract associated with retinal detachment or treatment received. The type of cataract, risk factors, and pathophysiology associated with each cause varies. This review highlights these different aspects of cataract in ROP including causes, pathophysiology, types of cataracts, and management. The management of these cases is critical in terms of the timing of cataract surgery and the challenges associated with surgery and posterior segment management for ROP. Anatomical differences, preoperative retina status, pupillary dilatation, neovascularization of iris in aggressive posterior ROP, fundus examination, amblyopia, and follow-up are various important aspects in the management of the same. The preoperative workup, intraoperative challenges, postoperative care, and rehabilitation in these individuals are discussed.

Refractive growth variability in the Infant Aphakia Treatment Study

PURPOSE

Prediction of refraction after cataract surgery in children is limited by the variance in rate of refractive growth (RRG3). This study compared RRG3 in aphakic and pseudophakic eyes with their fellow, normal eyes in the Infant Aphakia Treatment Study.

SETTING

Twelve clinical sites in the United States.

DESIGN

Randomized clinical trial.

METHODS

Infants randomized to unilateral cataract extraction had RRG3 calculated based on biometric data (axial length and keratometry) at cataract surgery and at 10 years of age, for both the normal and cataract eyes. Subjects were included if complete biometric data from both eyes were available both at surgery and at 10 years. Variance in RRG3 was compared between the groups with Pitman test for equality of variance between correlated samples.

RESULTS

Longitudinal biometric data were available for 103 of the 114 patients enrolled. RRG3 was -15.00 diopters (D) (3.00 D) for normal eyes (reported as mean [SD]), -17.70 D (6.20 D) for aphakic eyes, and -16.70 D (6.20 D) for pseudophakic eyes (P < .0001 for comparison of variances in RRG3 between normal and all operated eyes). Further analysis found differences in the variance in axial length growth (P < .0001) between operated and normal eyes; the variance in keratometry measurement change did not reach significance.

CONCLUSIONS

The standard deviation in the RRG3 of normal eyes in our study was half of that found in eyes that underwent cataract surgery.

The Myopic Shift in Aphakic Eyes in the Infant Aphakia Treatment Study After 10 Years of Follow-up

OBJECTIVES

To report the myopic shift in the aphakic eyes of a cohort of children who underwent unilateral cataract surgery during infancy and were then followed longitudinally for 10.5 years.

METHODS

One-half of the children enrolled in the Infant Aphakia Treatment Study (IATS) were randomized to aphakia and contact lens correction after unilateral cataract surgery. They then underwent ocular examinations using standardized protocols at prescribed time intervals until age 10.5 years.

RESULTS

Thirty of 57 children randomized to aphakia remained aphakic at age 10.5, having undergone unilateral cataract surgery at a median age of 1.6 (IQR: 1.1-3.1) months. The median refractive error (RE) in the 57 eyes randomized to aphakia immediately after cataract surgery was 19.01 D (IQR: 16.98-20.49) compared to 10.38 D (IQR: 7.50-14.00) for the 30 eyes that remained aphakic at age 10.5 years. The mean change in RE in aphakic eyes was -2.11 D/year up to age 1.5 years, -0.68 D/year from 1.5 to 5.0 years, and -0.35 D/year from age 5 to 10.5 years. At age 10.5 years, 18 patients continued to wear a contact lens correction (silicone elastomer, n=6; gas permeable, n=6; hydrogel, n=5; and silicone hydrogel, n=1) (median RE, 12.50 D), 9 wore only spectacles (median RE, 4.00 D), and 4 wore no correction (median RE, 11.25 D) to correct their aphakic eye.

CONCLUSIONS

The RE in aphakic eyes decreased by 44% from infancy to age 10.5 years. About two-thirds of children who remained aphakic at age 10.5 years continued to wear a contact lens.

Effect of Age at Primary Intraocular Lens Implantation on Refractive Growth in Young Children

PURPOSE

To evaluate the effect of age at primary intraocular lens (IOL) implantation on rate of refractive growth (RRG3) during childhood.

METHODS

A retrospective chart review was performed for children undergoing primary IOL implantation during cataract surgery. RRG3 was calculated for one eye from each patient using the first postoperative refraction, last refraction that remained stable (< 1.00 diopters [D] change/2 years), and the corresponding ages. RRG3 values for pseudophakic patients operated on from ages 0 to 5 months were compared with values for patients operated on at ages 6 to 23 months and 24 to 72 months. Patients with refractive errors that stabilized were grouped by age at surgery to compare age at refractive plateau.

RESULTS

Of 296 eyes identified from 219 patients, 46 eyes met the inclusion criteria. There was a statistically significant difference in RRG3 among age groups. The mean RRG3 value was -19.82 ± 5.23 D for the 0 to 5 months group, -22.32 ± 7.45 D for the 6 to 23 months group (0 to 5 months vs 6 to 23 months, P = .43), and -9.64 ± 11.95 D for the 24 to 72 months group (0 to 5 months vs 24 to 72 months, P = .01).

CONCLUSIONS

Age at primary IOL implantation affects the RRG3, especially for children 0 to 23 months old at surgery. Surgeons performing primary IOL implantation in infants may want to use age-adjusted assumptions, because faster refractive growth rates can be expected in young children. [J Pediatr Ophthalmol Strabismus. 2020;57(4):264-270.].

Ocular Component Development during Infancy and Early Childhood

SIGNIFICANCE

The study fills an important gap by providing a longitudinal description of development of the major structural and optical components of the human eye from 3 months to nearly 7 years of age. Normative development data may provide insights into mechanisms for emmetropization and guidance on intraocular lens power calculation.

PURPOSE

The purpose of this study was to describe the pattern of development of refractive error and the ocular components from infancy through early childhood.

METHODS

Cycloplegic retinoscopy (cyclopentolate 1%), keratophakometry, and ultrasonography were performed longitudinally on between 162 and 293 normal birth weight infants at 0.25, 0.75, 1.5, 3, 4.5, and 6.5 years of age.

RESULTS

Refractive error and most ocular components displayed an early exponential phase of rapid development during the first 1 to 2 years of life followed by a slower quadratic phase. Anterior and vitreous chamber depths, axial length, and crystalline lens radii increased at every visit. The crystalline lens thinned throughout the ages studied. The power of the cornea showed an early decrease, then stabilized, whereas the crystalline lens showed more robust decreases in power. The crystalline lens refractive index followed a polynomial growth and decay model, with an early increase followed by a decrease starting at 1 to 2 years of age. Refractive error became less hyperopic and then was relatively stable after 1 to 2 years of age. Axial lengths increased by 3.35 ± 0.64 mm between ages 0.25 and 6.5 years, showed uniform rates of growth across the range of initial values, and were correlated with initial axial lengths (r = 0.44, P < .001).

CONCLUSIONS

Early ocular optical and structural development appears to be biphasic, with emmetropization occurring within the first 2 years of infancy during a rapid exponential phase. A more stable refractive error follows during a slower quadratic phase of growth when axial elongation is compensated primarily by changes in crystalline lens power.

Factors influencing myopic shift in children after intraocular lens implantation

Introduction:

Intraocular lenses have always been a controversial topic in pediatric cataract surgery. In the early 1990s in the post-Soviet states of Eastern Europe, intraocular lenses promised an easier full-time correction and amblyopia treatment. Since 1991, ophthalmologists in Latvia have been implanting intraocular lenses in infants. Amount of the postoperative myopic shift and its influencing factors, analyzed in this article, are important indicators of congenital cataract treatment.

Materials and methods:

A retrospective chart review off 85 children (137 eyes) who underwent foldable posterior chamber intraocular lens implantation at the Clinical University Hospital in Riga, Latvia, from 1 January 2006 until 31 December 2016, was performed. Depending on the age at surgery, patients were divided into six groups: 1–6, 7–12, 13–24, 25–48, 49–84, and 85–216 months.

Results:

The largest and more variable myopic shift was found in a group of diffuse/total and nuclear cataract with surgery before the age of 6 months. There was a statistically significant correlation between the acquired best-corrected visual acuity and the amount of myopic shift (rs = 0.33; p < 0.001). Comparing the amount of myopic shift in two groups of different intraocular lens implantation target refraction tactics, we did not find statistically significant differences. Comparing the amount of myopic shift and implanted intraocular lens power, a negative, statistically significant correlation was found.

Conclusion:

The earlier the cataract extraction surgery and intraocular lens implantation is performed, the larger the myopic shift. The morphological type of cataract, best-corrected visual acuity, secondary glaucoma, and intraocular lens power influence the amount of myopic shift.

Validation of Guidelines for Undercorrection of Intraocular Lens Power in Children

PURPOSE

Initial undercorrection of intraocular lens (IOL power) is a common practice in children undergoing pediatric cataract surgery. However, the long-term refractive status of these children is largely unknown. The purpose of this study is to analyze the long-term refractive status of these children.

DESIGN

Retrospective observational study.

METHODS

We analyzed records of children (<7 years of age) who underwent cataract surgery with a primary IOL implantation and had completed follow-up to ≥7 years of age. Data were collected regarding demographics, etiology of cataract, method of undercorrection, and serial follow-up refractions. Prediction error was defined as refractive error minus emmetropia. The main outcome measure was prediction error at 7 years of age.

RESULTS

Eighty-four eyes of 56 children (28 unilateral and 28 bilateral cases) met the study criteria. The median age at surgery was 3.3 years (interquartile range 2.7-5 years), and the median follow-up period was 3.75 years. At 7 years of age, the median absolute prediction was 1.5 diopters (interquartile range 0.75-2 diopters). Seven of 84 (8.3%) children achieved emmetropia while an equal proportion were myopic (45%) or hypermetropic (46%). Prediction error (adjusted for using both eyes) at 7 years of age was not significantly different in any group (P > .05). Maximum myopic shift was observed in children <2 years of age. Age at surgery was the only significant factor that influenced prediction error (â = -0.32; P = .001).

CONCLUSION

This study suggests that children undercorrected using guidelines suggested by Enyedi and associates may achieve an acceptable refractive error at 7 years of age. However, in children <2 years of age, more hypermetropia may be observed. More studies are needed to validate various methods of undercorrection and compare with other guidelines.

Comparison of the rate of refractive growth in aphakic eyes versus pseudophakic eyes in the Infant Aphakia Treatment Study

PURPOSE

To compare the rate of refractive growth (RRG) between aphakic eyes and pseudophakic eyes in the Infant Aphakia Treatment Study (IATS).

SETTING

Twelve clinical sites across the United States.

DESIGN

Randomized clinical trial.

METHODS

Patients randomized to unilateral cataract extraction with contact lens correction versus intraocular lens (IOL) implantation in the IATS had their rate of refractive growth (RRG3) calculated based on the change in refraction from the 1-month postoperative examination to age 5 years. The RRG3 is a logarithmic formula designed to calculate the RRG in children. Two-group t tests were used to compare the mean refractive growth between the contact lens group and IOL group and outcomes based on age at surgery and visual acuity.

RESULTS

Longitudinal refractive data were studied for 108 of 114 patients enrolled in the IATS (contact lens group, n = 54; IOL group, n = 54). The mean RRG3 was similar in the contact lens group (-18.0 diopter [D] ± 11.0 [SD]) and the IOL group (-19.0 ± 9.0 D) (P = .49). The RRG3 value was not correlated with age at cataract surgery, glaucoma status, or visual outcome in the IOL group. In the aphakia group, only visual outcome was correlated with refractive growth (P = .01).

CONCLUSIONS

Infants' eyes had a similar rate of refractive growth after unilateral cataract surgery whether or not an IOL was implanted. A worse visual outcome was associated with a higher RRG in aphakic, but not pseudophakic, eyes.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Changing refractive outcomes with increasing astigmatism at longer-term follow-up for infant cataract surgery

PurposeTo present longer-term refractive and ocular health outcomes for patients who had primary intraocular lens (IOL) insertion following infant cataract surgery.Patients and methodsA retrospective review of all infant cataract cases at a tertiary children's hospital between 2003 and 2006 was conducted. Surgery was performed before 12 months of age. IOL power was calculated using the SRK/T formula targeting hyperopia based on the child's age; children under 3 months were targeted at +9.0 D, between 3 and 6 months at +6.0 D, and between 6 and 12 months at +3.0 D. Locally weighted scatterplot smoothing and mixed models were used.ResultsA total of 12 eyes from 9 children were included (4 bilateral and 5 unilateral). Spherical equivalent refraction decreased dramatically in the first 2 years of life, with milder changes from age 2 to 4 years and minimal changes thereafter. Cylinder increased until age 5 years at ∼0.57 dioptres/year (95% confidence intervals 0.27-0.87 D, P<0.001). Lens reproliferation was the commonest complication (58%). All children eventually developed strabismus.ConclusionEarly and frequent refraction is critical in the first 2 years of life to try and compensate for the rapid changes encountered in the growing eye. Astigmatism may be another important consequence to manage.

The change in axial length in the pseudophakic eye compared to the unoperated fellow eye in children with bilateral cataracts

PURPOSE

To compare the change in ocular axial length of the pseudophakic eye versus the fellow eye in children with bilateral cataracts who had surgery in only one eye.

METHODS

In this prospective cohort study, 50 eyes of 25 children with bilateral lamellar cataracts were analyzed. A complete ophthalmic examination and evaluation of axial length measurements by contact ultrasound biometry were performed in all eyes undergoing cataract surgery with IOL implantation and in contralateral eyes. The primary outcome measure was the percentage rate of growth between the final and initial measurements, defined as the initial minus the final measurement, with the difference being divided by the initial measurement and the result multiplied by 100.

RESULTS

Children aged 4-10 years of age were followed for a mean of 28.5 months. The values for axial length percentage rate of growth were significantly lower in pseudophakic eyes than in the unoperated, contralateral eyes (0.64% vs 2.09%, P < 0.05). Final visual acuity, follow-up time, and initial axial length did not affect the results. Pseudophakic eyes with posterior capsule opacification that underwent neodymium YAG laser showed a significantly higher rate of growth than unoperated eyes.

CONCLUSIONS

Axial length in children older than 4 years showed a trend toward stabilization, with lower changes in axial length measurements in pseudophakic eyes and a higher rate of axial growth in contralateral eyes.

Long-term risk of glaucoma after congenital cataract surgery

PURPOSE

To report the long-term risk of glaucoma development in children following congenital cataract surgery.

DESIGN

Retrospective interventional consecutive case series.

METHODS

We retrospectively reviewed the records of 62 eyes of 37 children who underwent congenital cataract surgery when <7 months of age by the same surgeon using a limbal approach. The Kaplan-Meier method was used to calculate the probability of an eye's developing glaucoma and/or becoming a glaucoma suspect over time.

RESULTS

The median age of surgery was 2.0 months and the median follow-up after cataract surgery was 7.9 years (range, 3.2-23.5 years). Nine eyes (14.5%) developed glaucoma a median of 4.3 months after cataract surgery and an additional 16 eyes (25.8%) were diagnosed as glaucoma suspects a median of 8.0 years after cataract surgery. The probability of an eye's developing glaucoma was estimated to be 19.5% (95% CI: 10.0%-36.1%) by 10 years after congenital cataract surgery. When the probability of glaucoma and glaucoma suspect were combined, the risk increased to 63.0% (95% CI: 43.6%-82.3%).

CONCLUSIONS

Long-term monitoring of eyes after congenital cataract surgery is important because we estimate that nearly two thirds of these eyes will develop glaucoma or become glaucoma suspects by 10 years after cataract surgery.

Selection of an initial contact lens power for infantile cataract surgery without primary intraocular lens implantation

PURPOSE

To provide guidelines for the selection of an initial contact lens (CL) power based on the preoperative characteristics of the patient in eyes undergoing infantile cataract surgery without primary intraocular lens (IOL) implantation.

DESIGN

Cohort study.

PARTICIPANTS

Eyes were included if cataract surgery was performed without primary IOL implantation before 1 year of age, a SilSoft CL (Bausch & Lomb, Rochester, NY) was placed immediately after surgery, and postoperative refraction data were available within 1 month after surgery.

METHODS

The target CL power was calculated by using the postoperative refraction at the corneal plane for each eye. A regression formula was derived using the targeted CL power and the axial length (AL). The CL power also was estimated using various formulas. An A-constant was derived to estimate CL power using IOL power calculation formula.

MAIN OUTCOME MEASURES

Contact lens power.

RESULTS

Fifty eyes of 50 patients were analyzed. Age at the time of cataract surgery was 2.4 ± 1.7 months. Refraction at the corneal plane was 29.6 ± 4.4 diopters (D). Regression analysis revealed that CL power=84.4 - 3.2 × AL (R(2) = 0.82; P<0.001). Contact lens power can be estimated using an A-constant of 112.176 in the IOL power calculation formula. If a CL power of 32 D had been used, 22 (44%) of 50 eyes would have needed a replacement of CL.

CONCLUSIONS

We devised guidelines on selecting the initial CL power based on preoperative AL. The IOL power calculator also can help to estimate CL power. Refraction at the conclusion of surgery in infants may be difficult, and preoperative biometry can be used to estimate CL power.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Reanalysis of refractive growth in pediatric pseudophakia and aphakia

BACKGROUND

The current model of refractive growth in children (RRG2) is calculated as the slope of aphakic refraction at the spectacle plane versus the logarithm of adjusted age. However, this model fails in infants because of the optical effect of vertex distance of a spectacle lens on the effective power at the cornea. In this study, we developed a new model of refractive growth (RRG3) that eliminates the optical effect of vertex distance on the RRG2 model.

METHODS

We calculated RRG3 values for pseudophakic and aphakic eyes previously analyzed for RRG2. Inclusion criteria were age ≤10 years at the time of cataract surgery and follow-up time between measured refractions of at least 3.6 years and at least the age at first refraction plus 0.6 years. For both pseudophakic and aphakic eyes, we compared RRG3 values in children who had cataract surgery before age 6 months with those in children aged 6 months or older.

RESULTS

A total of 78 pseudophakic and 70 aphakic eyes met the inclusion criteria. Ages at surgery ranged from 0.25 to 9 years, with a 9.5-year mean follow-up time. The mean RRG3 value was not significantly different between the surgical age groups for both pseudophakic eyes (P = 0.053) and aphakic eyes (P = 0.59).

CONCLUSIONS

The RRG3 values were not significantly different between the surgical age groups for both pseudophakic and aphakic eyes. Consequently, RRG3 is theoretically applicable even in the small eyes of infants having surgery before 6 months of age.

Refractive Surgery in Children

Refractive surgery in children is controversial. The main indications are bilateral high ametropia and anisometropia where conventional treatment with spectacles or contact lens is not tolerated. Other reported indications include accommodative strabismus and previous cataract surgery. The most commonly performed procedures currently are surface ablation procedures using excimer laser. The main disadvantage of surface ablation procedures is refractive regression, which is more pronounced in higher degrees of ametropia. More recently, there is a growing number of studies evaluating the safety and effectiveness of phakic intraocular lenses (IOLs) as an alternative surgical management for children who are noncompliant with conventional treatment and unsuitable for laser ablative procedures. The advantages of phakic IOLs are reversibility, predictability, and lack of regression. The principal concern with phakic IOL insertion is long-term endothelial cell loss. Clear lens extraction has been performed in patients with shallow anterior chambers beyond the range of corneal laser refractive procedures; however, major drawbacks include loss of accommodation and significant risk of retinal detachment. In summary, results to date show that refractive surgery can be successfully performed in children and meets an important need in a select subgroup of patients who are recalcitrant to traditional therapy. Issues that remain controversial are the age at which to perform surgery, choice of procedure, need for anesthesia, instability of refractive errors in children, and long-term safety considerations.

Long-term Outcomes of Undercorrection Versus Full Correction After Unilateral Intraocular Lens Implantation in Children

PURPOSE

To evaluate the impact of full correction vs undercorrection on the magnitude of the myopic shift and postoperative visual acuity after unilateral intraocular lens (IOL) implantation in children.

DESIGN

Retrospective case control study.

METHODS

The medical records of 24 children who underwent unilateral cataract surgery and IOL implantation at 2 to <6 years of age were reviewed. The patients were divided into 2 groups based on their 1-month-postoperative refraction: Group 1 (full correction) -1.0 to +1.0 diopter (D) and Group 2 (undercorrection) ≥+2.0 D. The main outcome measures included the change in refractive error per year and visual acuity for the pseudophakic eyes at last follow-up visit. The groups were compared using the independent groups t test and Wilcoxon rank sum test.

RESULTS

The mean age at surgery (Group 1, 4.2±0.9 years, n=12; Group 2, 4.5±1.0 years, n=12; P=.45) and mean follow-up (Group 1, 5.8±3.7 years; Group 2, 6.1±3.5 years; P=.69) were similar for the 2 groups. The change in refractive error (Group 1, -0.4±0.5 D/y; Group 2, -0.3±0.2 D/y; P=.70) and last median logMAR acuity (Group 1, 0.4; Group 2, 0.4; P=.54) were not significantly different between the 2 groups.

CONCLUSIONS

We did not find a significant difference in the myopic shift or the postoperative visual acuity in children aged 2 to <6 years of age following unilateral cataract surgery and IOL implantation if the initial postoperative refractive error was near emmetropia or undercorrected by 2 diopters or more.

Accuracy of the Holladay 2 intraocular lens formula for pediatric eyes in the absence of preoperative refraction

PURPOSE

To evaluate the prediction error in pediatric eyes using the Holladay 2 formula in the absence of preoperative refraction and to compare it with the prediction error using the Holladay 1, Hoffer Q, and SRK/T formulas.

SETTING

Storm Eye Institute, Charleston, South Carolina, USA.

DESIGN

Evaluation of diagnostic test or technology.

METHODS

Eyes having pediatric cataract surgery with intraocular lens (IOL) implantation were analyzed. One eye of bilateral cases was randomly selected for inclusion. Prediction error was calculated using the predicted postoperative refraction minus the actual postoperative refraction.

RESULTS

Forty-five eyes were included. The median age at surgery was 3.56 years and the median follow-up, 28 days. Using the Holladay 2, Holladay 1, Hoffer Q, and SRK/T formulas, the mean prediction error was 0.02 diopter (D) ± 0.91 (SD), -0.21 ± 0.90 D, 0.07 ± 1.01 D, and -0.47 ± 0.98 D, respectively. The mean absolute prediction error was 0.68 ± 0.61 D, 0.71 ± 0.58 D, 0.72 ± 0.71 D, and 0.84 ± 0.69 D, respectively. The Holladay 2 formula had the least prediction error for shorter eyes (<22.0 mm). The mean difference between the actual versus the predicted refraction was -0.05 D using Holladay 2 (P=.71), -0.02 D using Holladay 1 (P= .89), -0.12 D using Hoffer Q (P=.44), and 0.04 D using SRK/T (P=.78).

CONCLUSION

The Holladay 2 formula had the least prediction error and absolute prediction error even in the absence of preoperative refraction.

Longitudinal change in aphakic refraction after early surgery for congenital cataract

PURPOSE

To characterize the longitudinal changes of refraction in aphakic eyes after early surgery for congenital cataract and to evaluate longitudinally measured aphakic refraction (individual vs group mean) as a noninvasive indicator of postoperative disturbances in ocular development.

METHODS

Records of children who had cataract surgery during their first year of life between 1980 and 1995 were obtained from a prospective, population-based study of congenital cataract. Only children with regular follow-up were included. Postoperative aphakic refraction was calculated at the corneal plane. Data were obtained up to 36 months of age.

RESULTS

The study included 28 children (49 eyes) who underwent surgery at a median age of 2.8 months (range, 0-9 months). The decrease of aphakic refraction at the corneal plane followed a logarithmic trend (R(2) = 0.95). A total of 36 eyes followed this pattern, with no growth in 8 eyes and an increased growth rate in 1 eye with uncontrolled glaucoma and 4 eyes of 2 children with Down syndrome.

CONCLUSIONS

Most aphakic eyes follow a predictable, logarithmic change in refraction in the first 3 years of life, Longitudinal monitoring of refraction may prove to be a useful, noninvasive screening method for early detection of disturbances in aphakic eye growth.

Prediction error and accuracy of intraocular lens power calculation in pediatric patient comparing SRK II and Pediatric IOL Calculator

Background

Despite growing number of intraocular lens power calculation formulas, there is no evidence that these formulas have good predictive accuracy in pediatric, whose eyes are still undergoing rapid growth and refractive changes. This study is intended to compare the prediction error and the accuracy of predictability of intraocular lens power calculation in pediatric patients at 3 month post cataract surgery with primary implantation of an intraocular lens using SRK II versus Pediatric IOL Calculator for pediatric intraocular lens calculation. Pediatric IOL Calculator is a modification of SRK II using Holladay algorithm. This program attempts to predict the refraction of a pseudophakic child as he grows, using a Holladay algorithm model. This model is based on refraction measurements of pediatric aphakic eyes. Pediatric IOL Calculator uses computer software for intraocular lens calculation.

Methods

This comparative study consists of 31 eyes (24 patients) that successfully underwent cataract surgery and intraocular lens implantations. All patients were 12 years old and below (range: 4 months to 12 years old). Patients were randomized into 2 groups; SRK II group and Pediatric IOL Calculator group using envelope technique sampling procedure. Intraocular lens power calculations were made using either SRK II or Pediatric IOL Calculator for pediatric intraocular lens calculation based on the printed technique selected for every patient. Thirteen patients were assigned for SRK II group and another 11 patients for Pediatric IOL Calculator group. For SRK II group, the predicted postoperative refraction is based on the patient's axial length and is aimed for emmetropic at the time of surgery. However for Pediatric IOL Calculator group, the predicted postoperative refraction is aimed for emmetropic spherical equivalent at age 2 years old. The postoperative refractive outcome was taken as the spherical equivalent of the refraction at 3 month postoperative follow-up. The data were analysed to compare the mean prediction error and the accuracy of predictability of intraocular lens power calculation between SRK II and Pediatric IOL Calculator.

Results

There were 16 eyes in SRK II group and 15 eyes in Pediatric IOL Calculator group. The mean prediction error in the SRK II group was 1.03 D (SD, 0.69 D) while in Pediatric IOL Calculator group was 1.14 D (SD, 1.19 D). The SRK II group showed lower prediction error of 0.11 D compared to Pediatric IOL Calculator group, but this was not statistically significant (p = 0.74). There were 3 eyes (18.75%) in SRK II group achieved acccurate predictability where the refraction postoperatively was within ± 0.5 D from predicted refraction compared to 7 eyes (46.67%) in the Pediatric IOL Calculator group. However the difference of the accuracy of predictability of postoperative refraction between the two formulas was also not statistically significant (p = 0.097).

Conclusions

The prediction error and the accuracy of predictability of postoperative refraction in pediatric cataract surgery are comparable between SRK II and Pediatric IOL Calculator. The existence of the Pediatric IOL Calculator provides an alternative to the ophthalmologist for intraocular lens calculation in pediatric patients. Relatively small sample size and unequal distribution of patients especially the younger children (less than 3 years) with a short time follow-up (3 months), considering spherical equivalent only.

Theoretical strategy for choosing piggyback intraocular lens powers in young children

INTRODUCTION

The normal growth of a young child's pseudophakic eye can result in a large myopic shift. Temporary polypseudophakia using piggyback intraocular lenses (IOLs) has been proposed as a means to reduce the amount of myopic shift by removing the anterior IOL when the eye becomes sufficiently myopic. Since the rate of refractive growth can be used to predict the refractive curve over time in pseudophakic children, we used this knowledge to develop a theoretical strategy for choosing IOL power combinations for temporary polypseudophakia.

METHODS

We used a novel Pediatric Piggyback IOL Calculator to develop a strategy for choosing the powers of the anterior and posterior IOLs. We graphed the predicted results for several combinations of piggyback IOL powers and chose the combination of IOL powers that appeared to give the best results, based on the known rate of refractive growth (5.4 D) and its standard deviation (2.4 D). We aimed for a combination to minimize the hyperopic or myopic refractive error during the first 6 years of life to facilitate amblyopia management and minimize the refractive error at age 20 years.

RESULTS

We found optimal results when the initial postoperative goal refraction with polypseudophakia was moderate hyperopia and the anterior IOL had approximately 20% of the total required IOL power.

CONCLUSIONS

This theoretical strategy can be used to determine piggyback IOL powers to use in children.

Accuracy of biometry in pediatric cataract extraction with primary intraocular lens implantation

PURPOSE

To determine the accuracy of predicted postoperative refractive outcomes in pediatric patients having cataract surgery with intraocular lens (IOL) implantation and to compare them with other variables historically considered important in cataract surgery.

SETTING

Tertiary care referral hospital.

METHODS

This retrospective review comprised 203 eyes of 153 consecutive pediatric patients (< or = 18 years old) having cataract extraction with primary posterior chamber IOL implantation in the capsular bag. All cases were performed by 1 of 2 surgeons, and all refractions were performed manually by an experienced pediatric ophthalmologist using a retinoscope.

RESULTS

In all patients, the mean absolute value (MAE) of the prediction error was 1.08 diopters (D) +/- 0.93 (SD). Age at time of surgery and corneal (K) mean curvature were significantly correlated with the absolute value of the prediction error (P = .0006 and P = .0088, respectively). A multiple regression model showed that age at time of surgery and K mean curvature were the only 2 variables significantly associated with MAE; axial length, formula, surgeon, and A-scan type were not significantly associated with prediction error.

CONCLUSIONS

Data from 203 consecutive primary pediatric IOL implantations showed the heterogeneous nature of the variables involved in predictions of refractive outcomes in this population. The complexities of this issue support the need for specific methods of measurement and an IOL calculation formula for the pediatric population.

Intraocular lens power calculation in children

With improving surgical technique and equipment, the acceptable age for placing an intraocular lens in infants and children is becoming younger. The tools for predicting intraocular lens power have not necessarily kept up, as current theoretical and regression intraocular lens power prediction formulas are largely based on adult eyes at axial lengths, anterior chamber depth, and keratometric values much different than those seen in infants. In addition, the adult eye has matured and is no longer growing, whereas the eyes of infants and children may continue to note changes in axial length, keratometric values, and possibly optical characteristics. Another source of error in intraocular lens power selection that is more likely to occur in pediatric patients than in adult patients is inaccuracy in measurement of axial length or keratometric power. A review of current tools and considerations for intraocular lens power prediction in infants and children is presented.

Paediatric pseudophakia: analysis of intraocular lens power and myopic shift

BACKGROUND

At the Alberta Children's Hospital, the authors have been performing paediatric cataract extraction with intraocular lens (IOL) implant for over 10 years. The authors examined the amount of myopic shift that occurs in various age groups and cataract types, in order to evaluate the success of predicting the appropriate power of IOL to implant.

METHODS

This study is a retrospective review children undergoing small incision posterior chamber foldable IOL implantation between age 1 month and 18 years, from 1995 to 2005. 163 eyes of 126 patients underwent surgery. All patients were followed for a minimum of 6 months postoperatively. The children were divided into four groups at time of surgery: Group A: 1-24 months, Group B: 25-48 months, Group C: 49-84 months, Group D: 85 months-18 years.

RESULTS

The mean target refraction for the groups were: Group A: +6.37 D, Group B: +4.66 D, Group C: +1.95 D, and Group D: +0.97 D. Children under 4 years experienced the most myopic shift and the largest mean rate of refractive change per year. Mean change Group A: -5.43 D, Group B: -4.16 D, Group C: -1.58 D, Group D: -0.71 D. Eighty-nine per cent of patients with unilateral cataracts had a postoperative refraction within 3.00 D of the fellow eye at last follow-up visit (mean=3.16 years).

CONCLUSIONS

The rate of myopic shift is high in children under age 4 years at time of surgery, shifting as much as -12.00 D. The mean postoperative target refraction should probably be increased from previous literature recommendations. The patient's age at time of cataract surgery and the refractive power of fellow eye are all factors to consider when deciding what power IOL to surgically implant in a paediatric patient.

Amblyopia in the phakic eye after unilateral congenital cataract extraction

The treatment of unilateral congenital cataract remains a challenge because form deprivation early in life leads to amblyopia. Visual outcomes after congenital cataract extraction have improved dramatically with earlier surgery, greater attention to optical correction of the aphakia, and part-time occlusion therapy of the phakic eye. A published review of unilateral congenital cataract studies between 1988 and 2004 found that 88% of patients with primary intraocular lens implantation achieved 20/200 or better visual acuity and a mean of 20% achieved 20/40 or better visual acuity. Improved outcomes are attributable, in part, to surgical intervention at an earlier age. It has been shown that surgical intervention during the first 6 weeks of age is associated with a better visual prognosis than surgery at a later age. In this report, we describe a patient with unilateral congenital cataract treated with cataract extraction and intraocular lens implantation at 8 weeks of age who had a better visual outcome in his operative eye than in his phakic eye.

Long-term refractive change after intraocular lens implantation in childhood

BACKGROUND

To determine refractive change occurring with age in children who had cataract removal with intraocular lens implantation and in whom the immediate postoperative refraction was targeted either to match the refractive error of the opposite eye in unilateral cases, or for only a small refractive error when surgery was bilateral.

METHODS

Retrospective review of the refractive error over time in 36 eyes of 25 children who underwent cataract removal (11 bilateral) with insertion of an intraocular lens from 1987 to 1998 and who had at least 4 years follow-up, but no glaucoma.

RESULTS

Mean age at surgery was 5.5 years (median 5.7 y, range 1.3-12 y), with a mean follow-up of 8 years (median 6 y, range 4-16 y). The average refraction followed a logarithmic decline with age. Although eyes with unilateral surgery had a slightly faster rate of change and lower final refraction than did eyes with bilateral surgery, this difference was not statistically significant. Variation from this trend was also observed in 3 patients. When the hyperopic refractive error created immediately after surgery was small, children usually became significantly myopic when older, often creating anisometropic myopia in unilateral cases.

INTERPRETATION

When implanting intraocular lenses bilaterally one should aim for a significant but balanced hyperopic correction immediately postoperatively in young patients, anticipating that there will be emmetropization with aging. Parents should be warned that variations can occur.

Visual acuity development after the implantation of unilateral intraocular lenses in infants and young children

PURPOSE

Intraocular lenses (IOLs) are now being implanted in infants and children with unilateral cataracts. However, there are no prospective data on the development of visual acuity after implantation. The aim of the present study was to prospectively assess the development of acuity in infants and preschool children who received IOLs or aphakic contacts lenses (CLs) after the extraction of a unilateral cataract.

METHODS

Visual acuity was assessed using Teller Acuity Cards and/or crowded HOTV tests at target ages of 6 months, 1, 2, 3, and 4 years.

RESULTS

Infants who received a primary IOL after extraction of dense congenital unilateral cataract (n = 5) showed improvement from an initially low mean visual acuity of 20/170 at 6 months to 20/85 at 12 months and 20/54 at 4 years. Visual acuity in the IOL group was similar to that of children who had good-to-excellent compliance with CL wear (n = 36; 4-year visual acuity 20/50) and better than that of children who had moderate-to-poor compliance (n = 11; 4-year visual acuity 20/135). Children who received IOLs after extraction of developmental unilateral cataracts by 6 months (n = 4; 4-year visual acuity 20/55) had visual acuity development similar to those treated with CLs (n = 5; 4-year visual acuity 20/55). Children who received IOLs after extraction of developmental unilateral cataracts after 1 year of age (n = 18) had better visual acuity than children those treated with CLs (n = 4) at 4 years of age (20/40 vs. 20/135).

CONCLUSION

IOLs and aphakic CLs support similar visual acuity development after surgery for a unilateral cataract. IOLs may support better visual acuity development when compliance with CL wear is moderate to poor or when a cataract is extracted after 1 year of age.

Frequency and predictors of retinal detachment after pediatric cataract surgery without primary intraocular lens implantation

PURPOSE

To determine the frequency and to identify predictors of retinal detachment after pediatric cataract surgery without primary intraocular lens implantation.

METHODS

Retrospective review at an eye hospital identified 1017 eyes among 579 patients who underwent limbal-approach surgery without primary IOL implantation at age < or =16 years for cataract unassociated with other ocular abnormalities aside from microcornea. Patients had a minimum of 2 years postoperative follow-up. The outcome measure was the presence or absence of postcataract surgery retinal detachment, and analyses were performed on patients' eyes with adjustment for intrasubject correlation.

RESULTS

Mean postcataract surgery follow-up was 6.8 +/- 3.6 years (range, 2.0 to 18.3 years). Retinal detachment developed in 33 (3.2%) of the 1017 patients' eyes and was diagnosed at a mean of 6.8 +/- 4.4 years postcataract surgery (range, 0.4 to 14.8 years). Multivariable Cox proportional hazards regression analysis with adjustment for intrasubject correlation identified an aphakic refractive error more myopic than the age-adjusted aphakic norm [hazard ratio (HR), 5.9; 95% confidence interval (CI), 1.9 to 18.0; P = 0.002] and postcataract surgery wound dehiscence (HR, 15.4; 95% CI, 2.2 to 108.5; P = 0.006) as predictors of retinal detachment; a primary posterior capsulotomy/anterior vitrectomy procedure was not predictive of retinal detachment.

CONCLUSIONS

Retinal detachment is infrequent following pediatric cataract surgery without primary IOL implantation, at least with short-term follow-up. A postoperative aphakic refractive error more myopic (less hyperopic) than the age-adjusted aphakic norm is predictive of this complication.

Long-term follow-up of eye growth in pediatric patients after unilateral cataract surgery with intraocular lens implantation

PURPOSE

To evaluate the refractive status, axial length, and refractive power of the cornea in pediatric patients after unilateral cataract surgery and intraocular lens implantation.

METHODS

Refractive state, refractive power of cornea, and axial length were measured both in the operated and nonoperated eyes in 15 patients (age at surgery = 5 to 15 years; mean, 10.3) before and 4 to 15 years (mean, 9.7) after unilateral cataract surgery.

RESULTS

After surgery, visual acuity was 20/40 or better in 79% of operated eyes. Myopic changes, representing the difference between postoperative refraction at last follow-up and postoperative refraction at 1 year after surgery, were noted in the operated eyes at the end of study (mean, -5.02 D), but there were no significant differences in axial length (Wilcoxon signed rank test P >.05) or refractive power of the cornea between operated and nonoperated eyes (paired Student t test P >.05).

CONCLUSION

Myopic shift after cataract surgery with intraocular lens implantation may occur even in older children.

Development of primary axial myopic anisometropia

Assessment of refractive errors is an integral part of the treatment of ophthalmic problems. This is especially important in pediatric patients for early diagnosis of strabismus and amblyopia. In anisometropic amblyopia, careful monitoring of the refractive error is necessary. The following case history describes a patient who developed myopic axial anisometropia at age one. It suggests that the development of myopic axial anisometropia may be different than our present understanding. We reviewed the literature and found no description of the onset of myopic axial anisometropia.

Minimal myopic shift in pseudophakic versus aphakic pediatric cataract patients

PURPOSE

To evaluate postoperative refractive changes in aphakic and pseudophakic children in a comparative case series.

METHODS

The medical records of pediatric patients with aphakia and pseudophakia were reviewed retrospectively. The mean change in refractive error from one postoperative examination to the next was calculated at each age to give aggregate curves of postoperative refractive change for each group.

RESULTS

A total of 233 aphakic and 92 pseudophakic eyes were studied. The median age at the time of surgery was 0.8 years (range, 0.0-16 years) for patients with aphakia and 7.3 years (range, 1.5-19.9 years) for patients with pseudophakia (P <.0001). The postoperative refraction curves at comparable ages of 2 to 20 years showed a total mean myopic shift of 1.5 D for patients with pseudophakia and 7.8 D for patients with aphakia. An age-matched subset of patients with aphakia also showed more myopic shift than those with pseudophakia.

CONCLUSIONS

Pseudophakic eyes show less postoperative myopic shift than aphakic eyes. Selecting intraocular lens powers aimed at producing initial emmetropic refractions has been a good strategy in our cohort of patients with pseudophakia. However, our data are insufficient for conclusions regarding children with pseudophakia younger than 2 years, in whom larger myopic shifts may occur.

Prospective analysis of pediatric pseudophakia: myopic shift and postoperative outcomes

PURPOSE

Limited data exist about long-term refractive changes in eyes of children with intraocular lens (IOL) implantation. Information of postoperative results should allow more accurate predictions for IOL power implantation in children. Data regarding IOL complications, including secondary membranes, myopic shift, stereopsis, and pseudophakic glaucoma should also be reported.

METHODS

In a prospective study, the refractive errors of all pediatric patients between 12 months and 18 years who had cataract surgery and IOL implantation were evaluated at 4 weeks, 3 months, 6 months, 1 year, and every 6 months thereafter. All patients were followed for a minimum of 3 years.

RESULTS

Fifty-two eyes of 42 patients met inclusion criteria. Forty-two eyes had developmental cataracts. There were 10 bilateral cases. Of the 52 eyes, 85% had 20/40 vision or better. Visual acuity of 20/30 or better was achieved in 95% of bilateral eyes. In unilateral cataracts, visual acuity was 20/50 or better in 74% of eyes. Mean follow-up time was 5.45 years with a range of 3 to 10.5 years. Mean follow-up by age group ranged between 4.38 and 6.35 years. Children operated on at 12 months to 2 years of age had a mean myopic shift of -5.96 D; children operated on at 3 and 4 years of age had a -3.66 D shift; children operated on at 5 and 6 years of age had a shift of -3.40 D; children operated on at 7 and 8 years of age had a shift of -2.03 D; children operated on at 9 and 10 years of age had a mean shift of -1.88 D; children operated on at 11 to 14 years of age had a shift of -0.97 D; children operated on at 15 to 18 years of age had -0.38 D shift. No cases of pediatric pseudophakic glaucoma were observed. Secondary membrane occurred in 72% of eyes when the capsule was left intact. The operated eye showed a greater mean myopic shift than the nonoperated eye. No statistically significant difference in refractive change was found comparing amblyopic to nonamblyopic eyes or traumatic to nontraumatic cataracts.

CONCLUSIONS

The greatest rate of refractive growth or change occurred between 1 and 3 years of age. After age 3 years, the rate of refractive growth followed a more linear trend. Based on this study, we have provided a guide for selecting IOL power in pediatric cataract cases using current formulas with the understanding that new formulas will need to be devised to better predict IOL power in children.

Case series of 12 children with progressive axial myopia following unilateral cataract extraction

PURPOSE

We report the occurrence of unilateral progressive axial myopia ipsilaterally in a retrospective analysis of 12 children following uniocular cataract surgery.

METHODS

A retrospective analysis of the case records of children who had developed progressive ipsilateral axial myopia following unilateral cataract surgery was done. Follow-up ranged from 4 years to 14 years.

RESULTS

Twelve children, 7 male and 5 female, were eligible for the study. Mean age at the time of cataract surgery was 6.7 +/- 2.5 years (range, 4-11 years) and follow-up period was 7.8 +/- 3.1 years (range, 4-14 years). Ten children (83.3%) had traumatic cataracts of which 8 had undergone repair of penetrating eye injuries and 2 had suffered blunt trauma. Two patients (16.7%)had been operated for unilateral developmental cataracts. Three children had aphakia and nine had pseudophakia. Degree of myopic shift ranged from -4.75 D to -15 D (mean, -7.35 +/- 3.51 D). Axial length difference between the 2 eyes ranged from 1 mm to 3.5 mm (mean, 2.2 +/- 0.9 mm). Mean increase of axial length from preoperative recording to final follow-up was 2.53 +/- 0.90 mm (range, 1.6-4 mm). Three children had to undergo IOL explantation and 1 had posterior chamber intraocular lens exchange due to high unilateral myopia. The rest were visually rehabilitated with either spectacles or contact lenses.

CONCLUSION

Following cataract surgery pediatric eyes may suffer from progressive axial myopia. Trauma or multiple ocular surgeries may be predisposing factors.

Refractive change in pediatric pseudophakia: 6-year follow-up

PURPOSE

To evaluate the long-term evolution of refractive error changes in eyes of children who have primary intraocular lens (IOL) implantation to allow more accurate prediction of what IOL power should be implanted at a given age.

SETTING

Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.

METHODS

This study comprised all children between 2 and 15 years of age who had posterior chamber IOL implantation and who were followed for a minimum of 4 years postoperatively. Thirty-eight eyes of 27 patients with a mean follow-up of 6.1 years were evaluated. All refractions were performed manually by an experienced pediatric ophthalmologist.

RESULTS

Children operated on at age 2 or 3 years had a mean myopic shift of 4.60 diopters (D) (range 0.50 to 10.75 D) over a mean of 5.8 years postoperatively. Children operated on at age 6 or 7 years had a mean myopic shift of 2.68 D (range 0.50 to 6.60 D) over a mean of 5.3 years. Children operated on at age 8 or 9 years had a mean myopic shift of 1.25 D (range -0.75 to 2.60 D) over a mean of 6.8 years. Patients operated on between ages 10 and 15 years had a mean shift of 0.61 D (range 0 to 1.90 D) over a mean of 5.7 years.

CONCLUSIONS

The mean rate of myopic shift decreased throughout childhood, and the range of shift among individuals narrowed as patient age increased. However, the ability to predict future myopic shift for a given individual remains difficult, especially in younger patients.

A comparison of the rate of refractive growth in pediatric aphakic and pseudophakic eyes

OBJECTIVE

To compare the rate of refractive growth in pseudophakic children's eyes to that of aphakic eyes.

DESIGN

Multicenter, retrospective observational case series.

PARTICIPANTS

83 patients with pseudophakic eyes (100 eyes) and 74 patients with aphakic eyes (106 eyes), with an age of surgery between 3 months and 10 years and a minimum follow-up time of 3 years or more, depending on the age at surgery.

METHODS

A logarithmic model was used to analyze the rate of refractive growth for each eye.

MAIN OUTCOME MEASURES

Age at surgery, intraocular lens power, intraocular lens A-constant, initial postoperative refraction, final refraction, and final age.

RESULTS

Overall, pseudophakic eyes showed a lesser rate of refractive growth than aphakic eyes (-4.6 diopter vs. -5.7 diopter, P = 0.03). This trend was also present but less significant when the eyes were grouped into those less than 6 months of age at surgery (-3.3 diopter vs. -4.6 diopter, P = 0.09) and older patients (-5.0 diopter vs. -6.1 diopter, P = 0.07). However, the mean quantity of myopic shift was greater in pseudophakic eyes than in aphakic eyes (-5.26 diopter vs. -4.54 diopter), despite shorter follow-up times in the pseudophakic eyes. This is due to the optical effects of a constant intraocular lens power in a growing eye.

CONCLUSIONS

Pediatric pseudophakic eyes have a slightly lesser rate of refractive growth than aphakic eyes. The new rate values should be used for predicting future refractions in these eyes.

Effect of age at time of cataract surgery on subsequent axial length growth in infant eyes

PURPOSE

To determine whether removal of the crystalline lens and placement of an intraocular lens (IOL) in human infant eyes retard the growth of the pseudophakic eye.

METHODS

A unilateral lensectomy with placement of a posterior chamber IOL in the sulcus was performed in 11 infants between 2 and 4 months of age. Axial length measurements of both eyes were obtained preoperatively and postoperatively.

RESULTS

Patients were followed for a mean of 5.6 years. In 7 patients, the mean axial growth was 0.46 mm less in the pseudophakic eye than in the fellow eye (range 0.15 to 0.70 mm). In 1 patient, there was no interocular axial length difference and in 3, the pseudophakic eye was longer. When measurements from the only patient with microphthalmia were excluded, the interocular difference in axial growth was highly significant (signed rank test, P = .006). Median visual acuity of the pseudophakic eyes at the last follow-up was 20/60 (range 20/30 to 20/200). The final visual acuity in the pseudophakic eyes did not correlate with the degree of interocular axial length difference (P > .05).

CONCLUSIONS

Our study suggests there may be a reduction in axial growth in infantile eyes following cataract extraction and IOL implantation. This effect probably reduces the magnitude of the myopic shift in these eyes.

Refractive changes after pediatric intraocular lens implantation

PURPOSE

To report refractive changes after cataract surgery and intraocular lens implantation in infants and children.

METHODS

In an ongoing prospective study, the refractive errors of all patients younger than 18 years undergoing intraocular lens implantation were determined at 6 weeks, 3 months, 6 months, and 1 year, and at least yearly thereafter. All patients with greater than 6 months of follow-up were included in the study.

RESULTS

Eighty-three eyes of 81 patients were identified. Cataracts were traumatic in 32 eyes (38%) and developmental in 42 eyes (50%). At implantation, the mean (+/-SD) age was 6.3 +/- 4.6 years (range, 9 months to 17 years). The mean follow-up was 26.6 months (range, 6 months to 6.6 years). Patients 0 to 2 years old at the time of implantation demonstrated a mean myopic shift of -3.00 diopters during a mean follow-up period of 2.5 years. Patients 2 to 6 years old at the time of implantation demonstrated a mean myopic shift of -1.50 diopters in a similar follow-up period. Children aged 6 to 8 years experienced a mean myopic shift of -1.80 diopters during a mean follow-up period of 3.0 years, while children older than 8 years at the time of intraocular lens implantation experienced a mean myopic shift of -0.38 diopters during a mean follow-up period of 1.8 years. On average, the operated-on eye showed a greater mean myopic shift than the fellow eye. No statistically significant differences in refractive change were found in comparing amblyopic to nonamblyopic eyes, traumatic to nontraumatic cataracts, or primary to secondary intraocular lenses.

CONCLUSIONS

Our data demonstrate a trend toward increasing postoperative myopia in pediatric patients undergoing intraocular lens implantation. This myopic shift is greatest in the younger age groups and persists until at least 8 years of age. There is much variability in the postoperative refractive changes, and predicting exactly when and where the refraction will stabilize for an individual patient is difficult.

Intraocular lens calculator for childhood cataract

PURPOSE

To evaluate a computer program to predict the pseudophakic refraction of a child at any age.

SETTING

A pediatric ophthalmology practice.

METHODS

A computer program was written for Windows 95 that calculates the initial postoperative pseudophakic refraction of a child using Holladay's formula, given the axial length and keratometry readings. The logarithmic model was used to predict the ultimate refraction at age 20 years and chart the predicted curve of refractive error with standard deviations.

RESULTS

The program provided a graph of a child's predicted pseudophakic refraction versus age that would allow the surgeon to dynamically view the effects of changing the intraocular lens (IOL) power.

CONCLUSIONS

If pseudophakia and aphakia have the same effect on the growth of the eye, this program should accurately predict the myopic shift of a pseudophakic child. This could help guide the surgeon's choice of IOL power.

Theoretic refractive changes after lens implantation in childhood

OBJECTIVE

Children with aphakia tend to have decreasing hyperopia as they grow older. No large study of the long-term refractive changes in children with pseudophakia has been published, although myopic shifts of greater than 10 diopters (D) have been reported. The authors used the refractions of children with aphakia and long follow-up to calculate the theoretic long-term refractive effects of pseudophakia.

DESIGN

The study design was a chart review of eyes that underwent cataract surgery before age 10 with documented refractions for more than 7 years.

PARTICIPANTS

Ninety-three eyes were studied.

INTERVENTION

The initial aphakic refractions of the study eyes were used to calculate the intraocular lens (IOL) powers that would have been required to give emmetropia at cataract removal. The aphakic refractions at last follow-up were used to calculate the final pseudophakic refractions, and these were compared with the predictions of a logarithmic model of myopic shift.

RESULTS

The mean follow-up time was 11 years. The median calculated pseudophakic refraction at last follow-up was -6.6 D with a range of -36.3 to +2.9 D. Children who underwent surgery in the first 2 years of life had a substantially greater myopic shift than older children (P < 0.001) and a larger variance in this myopic shift (P < 0.001). The logarithmic model accurately predicted the final refraction within 3 D in 24% of eyes undergoing surgery before 2 years of age and in 77% of eyes undergoing surgery after this age.

CONCLUSIONS

Pseudophakia in children is predicted to result in a large quantity of myopic shift, particularly in very young children. An IOL power chosen to leave a child initially hyperopic should lessen both the quantity of myopic shift and the extreme myopia that can result with growth. The surgeon who implants IOLs in young children must be prepared for a wide variation in long-term myopic shift.