The Optics of Aphakic and Pseudophakic Eyes in Childhood

Association Between Preoperative Ocular Parameters and Myopic Shift in Children Undergoing Primary Intraocular Lens Implantation

Purpose

To evaluate the association between preoperative ocular parameters and myopic shift following primary intraocular lens (IOL) implantation in pediatric cataracts.

Methods

Eyes from pediatric patients undergoing bilateral cataract surgery with primary IOL implantation were included. Eyes were grouped by age at surgery and subdivided into three axial length (AL) subgroups and three keratometry subgroups. Mixed-effects linear regression was utilized to assess the trend in myopic shift among subgroups. Multivariable analysis was performed to determine factors associated with myopic shift.

Results

A total of 222 eyes were included. The median age at surgery was 4.36 years (interquartile range [IQR], 3.16-6.00 years) and the median follow-up was 4.18 years (IQR, 3.48-4.64 years). As preoperative AL increased, a decreased trend was observed in myopic shift and rate of myopic shift (P = 0.008 and P = 0.003, respectively, in the 4 to <6 years old group; P = 0.002 and P < 0.001, respectively, in the ≥6 years old group). Greater myopic shift and rate of myopic shift were associated with younger age at surgery (P = 0.008 and P = 0.008, respectively). Both myopic shift and rate of myopic shift were negatively associated with AL.

Conclusions

Age at surgery and preoperative AL were associated with myopic shift in pediatric cataracts following primary IOL implantation. Adjusting the target refraction based on preoperative AL could potentially improve patients' long-term refractive outcome.

Translational Relevance

This study may help to guide the selection of postoperative target refraction according to age at surgery and preoperative ocular parameters for pediatric cataracts.

External Validation of a Model to Predict Postoperative Globe Axial Length in Children After Bilateral Cataract Surgery

PURPOSE

To perform the external validation of a model to predict postoperative axial length (AL) in children over 2 years of age who were undergoing bilateral cataract surgery with primary intraocular lens (IOL) implantation.

DESIGN

Validation study using a retrospective case series.

METHODS

Using a population different from the one that created the model, but with the same characteristics regarding age, bilateral cataract, primary IOL implantation, and follow-up assessment, AL was estimated. The AL values estimated by the model were compared with the AL measured in the follow-ups.

RESULTS

In all, 55 eyes of 30 children were selected for this study; in 5 children with bilateral cataracts, only 1 eye was included. The median age at the time of surgery was 5.01 years. Follow-up AL measurements were obtained for 179 visits. The median age at the final follow-up visit was 10.15 years. The median AL measured and estimated by the model in all visits were 22.37 mm and 22.16 mm, respectively (Pearson coefficient: 0.9534; Lin correlation: 0.9258). In the Bland-Altman analysis, the 95% limit of agreement between the 2 methods (measured and estimated AL) was 0.71 to -1.19. In 3 eyes (1.68%) with AL shorter than 21.2 mm, the difference was >0.71, and in 9 eyes with AL longer than 22.5 (5.03%), it was less than -1.19. The median AL measured and estimated at the final visit were 22.69 mm and 22.43 mm, respectively.

CONCLUSION

Our previously developed prediction model for globe AL growth demonstrated good external validity by accurately predicting measured AL changes with growth in the validation cohort.

Factors associated with progressive anisometropia after bilateral intraocular lens implantation in patients with pediatric cataract

OBJECTIVES

To identify factors associated with progressive anisometropia after bilateral intraocular lens (IOL) implantation in patients with pediatric cataract.

METHODS

Clinical and standardized questionnaire data were collected for Sixty-eight patients with pediatric cataract (136 eyes) who underwent bilateral IOL implantation and at least 1 year of follow-up. Univariate and multivariate linear regression models were used to identify factors associated with postoperative anisometropia.

RESULTS

The median age at IOL implantation was 3.2 years (range: 1-12.4 years), and median follow-up time was 5.7 years (range: 1.1-14 years). At 1 month postoperatively and at the last follow-up, there were 19 (27%) and 31 (46%) cases of anisometropia ≥1 D, 9 (13%) and 15 (22%) cases of anisometropia ≥2 D, and 2 (3%) and 9 (13%) cases of anisometropia ≥3 D, respectively. Compared with 1 month postoperatively, the amount of anisometropia increased in 45 (67%) patients. Greater anisometropia one year or more after bilateral IOL implantation was associated with larger intereye difference in IOL power (P = 0.032, 95%CI 0.013 to 0.285), intereye difference in preoperative axial length (P = 0.018, 95%CI -1.247 to -0.123), presence of strabismus (P = 0.017, 95%CI 0.063-0.601), anisometropia at 1 month postoperatively (P = 0.001, 95%CI 0.126-0.478), and intereye difference in axial length at the last follow-up (P = 0.047, 95%CI 0.005-0.627).

CONCLUSION

Anisometropia might progress after bilateral IOL implantation in patients with pediatric cataract. Greater intereye difference in IOL power, presence of strabismus might increase the potential of progressive anisometropia.

Axial length and corneal curvature of normal eyes in the first decade of life

BACKGROUND/AIMS

To establish normative curves for axial length and corneal curvature in the first decade of life.

METHODS

This is a cross-sectional study from a single institution in the United States. Children from 0- to 10-years of age with no underlying ocular pathology were prospectively enrolled to obtain ultrasound biometry and hand-held keratometry while under anaesthesia for an unrelated procedure. Older cooperative children had optical biometry obtained in-office. Logarithmic quantile regression models were used to determine the change in axial length and average keratometry as a function of age.

RESULTS

Single-eye measurements from 100 children were included. 75% of children were White and 49% female. Median axial length ranged from 20.6 mm (IQR, 20.2 to 21.1 mm) at age one year to 23.1 mm (IQR, 22.5 to 23.8 mm) at age ten years. Median average keratometry ranged from 44.1 D (IQR, 42.6 to 45.4 D) at age one year to 43.5 (IQR, 42.2 to 44.0 D) at age ten years. As age increased, there was a significant increase in axial length (0.74 mm per doubling of age; 95% CI, 0.62 to 0.82 mm), and a non-significant trend towards lower average keratometry (-0.21 D per doubling of age; 95% CI, -0.62 to 0.08 D).

CONCLUSIONS

We provide a set of normative charts for axial length and corneal curvature which may facilitate the identification of eyes outside the normal range and assist in the management of ocular conditions such as glaucoma or cataract.

Predicting axial length in patients with Marfan syndrome and ectopia lentis after modified capsular tension ring and intraocular lens implantation

PURPOSE

To predict the growth of axial length (AL) in patients with Marfan syndrome (MFS) and ectopia lentis (EL).

SETTING

Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN

Consecutive retrospective case series.

METHODS

Eyes were evaluated that had modified capsular tension ring and intraocular lens (IOL) implantation. The rate of AL growth (RALG) was calculated using AL divided by log10-transformed age. A multivariate linear regression model of RALG was developed after validation.

RESULTS

128 patients with MFS and EL were enrolled with a median follow-up duration of about 3 years. RALG was independent of age between 3 years and 15 years old ( P = .799) and decreased to 0 thereafter ( P = .878). Preoperative AL was associated with RALG in patients under 15 years old ( P = .003). Beta values for the final model of RALG were as below: intercept (-9.794) and preoperative AL (0.664). The postoperative AL was predicted as: postAL = preAL + RALG × log 10 ([postAge + 0.6]/[preAge + 0.6]). The mean prediction error was -0.003 (95% CI, -0.386 to 0.3791) mm and the mean absolute percentage error was 1.93% (95% CI, 0.73% to 3.14%). A Python-based calculator was developed to use the predicted AL in selecting IOL power and setting undercorrection.

CONCLUSIONS

The AL growth of patients with MFS followed a logarithmic pattern and ceased at about age 15. A prediction model of postoperative AL was established for individual MFS patients between 3 and 15 years old, which could potentially optimize the IOL power selection.

Pediatric cataract surgery: considerations and updates in diagnosis and management

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of updates in the diagnosis and management of pediatric cataracts, with an emphasis on recent discoveries in the last two years.

RECENT FINDINGS

Pediatric cataracts remain an infrequent but significant disease with vision threatening consequences. Although much of the management has not changed historically, more recent updates, particularly borrowed from adult cataract management, have influenced the field of cataract management in children. Even these studies emphasize that pediatric cataracts are a distinct clinical entity from adult-onset cataracts, and further research is needed to optimize the diagnosis and management of cataracts in childhood.

SUMMARY

This is an overview of the recent advancements in the diagnosis of management of pediatric cataracts, with advancements that originate from the adult cataract surgery field in addition to studies that challenge classical surgical techniques to make cataract surgery safer and to promote amblyopia therapy.

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.

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.

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.

The accuracy of intraocular lens calculation varies by age in the Infant Aphakia Treatment Study

Refraction predictions from intraocular lens (IOL) calculation formulae are inaccurate in children. We sought to quantify the relationship between age and prediction error using a model derived from the biometry measurements of children enrolled in the Infant Aphakia Treatment Study (IATS) when they were ≤7 months of age. We calculated theoretical predicted refractions in diopters (D) using axial length, average keratometry, and IOL powers at each measurement time point using the Holladay 1 formula. We compared the predicted refraction to the actual refraction and calculated the absolute prediction error (APE). We found that the median APE was 1.60 D (IQR, 0.73-3.11 D) at a mean age (corrected for estimated gestational age) of 0.20 ± 0.14 years and decreased to 1.11 D (IQR, 0.42-2.20 D) at 10.60 ± 0.27 years. We analyzed the association of age with APE using linear mixed-effects models adjusting for axial length, average keratometry, and IOL power and found that as age doubled, APE decreased by 0.25 D (95% CI, 0.09-0.40 D). The accuracy of IOL calculations increases with age, independent of biometry measurements and IOL power.

Broadening the Mutation Spectrum in GJA8 and CHMP4B: Novel Missense Variants and the Associated Phenotypes in Six Chinese Han Congenital Cataracts Families

Purpose: To broaden the mutation and phenotype spectrum of the GJA8 and CHMP4B genes and to reveal genotype-phenotype correlations in a cohort of Chinese patients with congenital cataracts (CCs).

Methods: Six Chinese Han families with CCs inherited in an autosomal dominant (AD) pattern were recruited for this study. All patients underwent full ocular examinations. Genomic DNA was extracted from the leukocytes of peripheral blood collected from all available patients and their unaffected family members. Whole-exome sequencing (WES) was performed on all probands and at least one of their parents. Candidate variants were further confirmed by Sanger sequencing. Bioinformatic analysis with several computational predictive programs was performed to assess the impacts of the candidate variants on the structure and function of the proteins.

Results: Four heterozygous candidate variants in three different genes (CRYBB2, GJA8, and CHMP4B) were identified in affected individuals from the six families, including two novel missense variants (GJA8: c.64G > C/p. G22R, and CHMP4B: c.587C > G/p. S196C), one missense mutation (CRYBB2: c.562C > T/p. R188C), and one small deletion (GJA8: c.426_440delGCTGGAGGGGACCCT/p.143_147delLEGTL). The three missense mutations were predicted as deleterious in all four computational prediction programs. In the homologous model, the GJA8: p.143_147delLEGTL mutation showed a sequence deletion of five amino acids at the cytoplasmic loop of the Cx50 protein, close to the third transmembrane domain. Patients carrying mutations in the same gene showed similar cataract phenotypes at a young age, including total cataracts, Y-sutural with fetal nuclear cataracts, and subcapsular cataracts.

Conclusion: This study further expands the mutation spectrum and genotype-phenotype correlation of CRYBB2, GJA8, and CHMP4B underlying CCs. This study sheds light on the importance of comparing congenital cataract phenotypes in patients at the same age stage. It offers clues for the pathogenesis of CCs and allows for an early prenatal diagnosis for families carrying these genetic variants.

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.

Predicting future axial length in patients with paediatric cataract and primary intraocular lens implantation

OBJECTIVE

Creating a model to predict Axial Length (AL) growth in paediatric cataract and evaluating influence factors.

MATERIAL AND METHODS

Eyes with AL measured at surgery and at least one measurement after a 6-month period, from children with unilateral or bilateral cataract and primary IOL implantation, were evaluated. A "rate of axial length growth" (RALG) was calculated for every single eye using these AL measurements and log₁₀ age. One average RALG was calculated for All Eyes and for the groups of Bilateral and Unilateral, Gender, Age at the Surgery, different Visual Acuity, Bilateral Excluded and Not-excluded eye, and Affected and Not-affected eye in unilateral, for comparisons.

RESULTS

Average age at surgery from 76 children was 2.83 ± 2.74 (0.11-12.21) years with follow up of 2.84 ± 1.84 (0.52-8.17) years, 29 (37.66%) had unilateral cataract. A total of 357 AL measurements were used, average of 4.70 ± 2.13 (2-10) measurements per eye. The average RALG for all eyes was 4.51 ± 3.06. There were no RALG significant differences comparing Unilateral and Bilateral eyes (p = 0.51), Male and Female (p = 0.26), Age at Surgery <0.5 and >0.5 years old (p = 0.21), both eyes in Bilateral cases (p = 0.70) and Unilateral Affected and Not-affected eyes (p = 0.18). The equation Al = initial AL + slope ×  Log₁₀ ((age + 0.6)⁄(initial age + 0.6)) estimates ALs in different ages.

CONCLUSIONS

A model to predict AL growth in paediatric cataract was developed. Different studied factors did not significantly influence AL growth.

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.].

Visual Acuity and Ophthalmic Outcomes in the Year After Cataract Surgery Among Children Younger Than 13 Years

Importance

Cataract is an important cause of visual impairment in children. Outcomes reported from a large clinical disease-specific registry can provide real-world estimates of visual outcomes and rates of adverse events in clinical practice.

Objective

To describe visual acuity and refractive error outcomes, as well as rates of amblyopia, glaucoma, and additional eye surgery, during the first year after lensectomy in children.

Design, Setting, and Participants

A prospective observational study was conducted from June 18, 2012, to July 8, 2015, at 61 pediatric eye care practices among 880 children younger than 13 years at the time of lensectomy in at least 1 eye with follow-up within 15 months after surgery. Statistical analysis was performed from December 12, 2016, to December 14, 2018.

Exposures

Lensectomy with or without implantation of an intraocular lens.

Main Outcomes and Measures

Visual acuity as well as rates of amblyopia, glaucoma, suspected glaucoma, and other intraocular surgery.

Results

Among the 880 children (432 girls and 448 boys; mean [SD] age at annual follow-up, 4.9 [3.8] years) in the study, lens surgery was bilateral in 362 (41.1%; 95% CI, 37.9%-44.4%) children and unilateral in 518 (58.9%; 95% CI, 55.6%-62.1%). An intraocular lens was implanted in 654 of 1132 eyes (60.2%; 95% CI, 57.0%-63.4% [proportions reported for eye-level outcomes account for the potential correlation induced by enrolling both eyes of some individuals; for participants who received bilateral surgery, these numbers will differ from the quotient of the number of cases divided by the total sample size]). Amblyopia was identified in 449 children (51.0%; 95% CI, 47.7%-54.3%). In children age 3 years or older, mean visual acuity was 0.30 logMAR (about 20/40) in 153 bilateral pseudophakic eyes, 0.49 logMAR (about 20/63) in 141 unilateral pseudophakic eyes, 0.47 logMAR (about 20/63) in 21 bilateral aphakic eyes, and 0.61 logMAR (about 20/80) in 17 unilateral aphakic eyes. Mean visual acuity improved with older age at surgery in eyes with bilateral pseudophakia by 0.2 logMAR line (99% CI, 0.02-0.4; P = .005) and by 0.3 logMAR line (99% CI, 0.04-0.60; P = .004) in eyes with unilateral pseudophakia. A new diagnosis of glaucoma or suspected glaucoma was made in 67 of 1064 eyes that did not have glaucoma prior to lensectomy (5.9%; 95% CI, 4.6%-7.7%); 36 of 273 eyes with bilateral aphakia (13.2%; 95% CI, 9.0%-19.0%), 5 of 308 eyes with bilateral pseudophakia (1.5%; 95% CI, 0.6%-4.2%), 14 of 178 eyes with unilateral aphakia (7.9%; 95% CI, 4.7%-12.8%), and 12 of 305 eyes with unilateral pseudophakia (3.9%; 95% CI, 2.2%-6.8%). Additional intraocular surgery, most commonly vitrectomy or membranectomy to clear the visual axis, was performed in 189 of 1132 eyes (17.0%; 95% CI, 14.8%-19.6%).

Conclusions and Relevance

Amblyopia was frequently observed during the first year after lensectomy in this cohort of children younger than 13 years. For children age 2 years or older at surgery visual acuity was typically less than normal for age and was worse with unilateral cataract. Management of visual axis obscuration was the most common complication requiring surgical intervention during the first year after surgery.

Dynamic profile of ocular refraction in pediatric cataract patients after lens surgeries

AIM

To study the change in ocular refraction in patients with pediatric cataracts (PCs) after lens extraction.

METHODS

A total of 1258 patients who were undergoing cataract extraction with/without intraocular lens (IOL) implantation were recruited during preoperative examinations between Jan 2010 and Oct 2013. Patient ages ranged from 1.5mo to 14y. Follow-ups were conducted at 1wk, 1, and 3mo postoperatively and every 3mo in the first year, then 6mo thereafter. Ocular refraction [evaluated as spherical equivalent (SE)] and yearly myopic shift (YMS) were recorded and statistically analyzed among patients with age at surgery, baseline ocular refraction, gender, postoperative time and laterality (bilateral vs unilateral).

RESULTS

By Dec 31^st 2015, 1172 participants had been followed for more than 2y. The median follow-up period was 3y. The critical factors affecting the ocular refraction of PC patients were baseline ocular refraction, postoperative time for both aphakic and pseudophakic eyes. YMS grew most rapidly in young childhood and early adolescence.

CONCLUSION

After lens surgeries, ocular refraction in PC patients shows an individual difference of change. Further concerns should be raising to monitor the rapid myopic shift at early adolescence of these patients.

Interocular difference associated with myopic progression following unilateral lateral rectus recession in early school-aged children

PURPOSE

To compare refractive changes in operated eyes and fellow unoperated eyes following unilateral lateral rectus recession in early school-aged children.

STUDY DESIGN

A retrospective case control study.

METHODS

The medical records of children under ten years of age with intermittent exotropia who underwent unilateral lateral recession surgery were reviewed. The operated eyes were reviewed and the fellow unoperated eyes were used as control. The rate of myopic progression was calculated by spherical equivalent (SE) changes per year, and by the rate of refractive growth (RRG) equation.

RESULTS

SE showed a myopic shift one week after surgery and in the following months, from -1.43 ± 1.84 diopters (D) at 1 week post operation to -1.57 ± 2.22 D at one year and, finally -2.95 ± 2.97 D at the average 4.62 years following surgery. However, the SE shift was not significantly different from the unoperated eye. The low myopia group (under -3.0 D) showed a significantly higher myopic change in the operated eye until one year post operation (p = 0.022). The average myopic shift ratio was -0.53 ± 0.46 D yearly in the operated eye.

CONCLUSIONS

This study presents data of a large series of refractive changes secondary to lateral rectus recession, and of long-term myopia progression in Korean population.

Rigid Gas-Permeable Contact Lenses Fitting Philosophy for Unilateral Aphakic Infants

PURPOSE

To provide fitting guidelines with suggested powers and base curves (BCs) and diameters for initial rigid gas-permeable (RGP) contact lenses (CLs) selection for unilateral aphakic infants based on age.

METHODS

Records of 52 children (52 eyes) with RGP CLs to unilateral aphakia between 2014 and 2019 were evaluated. Refractive status was assessed by standard retinoscopy. The original BC and diameter were determined by keratometric readings and fluorescein pattern under sedation. Correlation analysis was performed between age and CLs parameters. Linear regression analysis was used to develop a model for estimating power with the help of infant's age. Subgroup analysis was performed by grouping the eyes into four groups according to age. Lens adjustments and adverse events were also evaluated.

RESULTS

The median age was 9.0 months (interquartile range [IQR], 5.25-13.0 months). The mean power and BC and diameter of the initial RGP CLs were 25.46±4.83 diopters, 7.57±0.40 mm, and 9.48±0.23 mm, respectively. All these parameters showed correlations with infant's age (Pearson r=-0.676, 0.367, and 0.497, respectively; P=0.000, 0.008, and 0.000, respectively). Regression analysis revealed that CL power =31.66 to 0.62×age (P<0.001). The median follow-up was 7.50 months (IQR, 3.0-11.0 months). Lens adjustments took about every 3 months before 1 year of age and every 5 months afterward (F=3.442; P=0.024). The RGP CLs provided ideal fit characteristics, and no severe lens-related adverse event occurred except only one patient had mild conjunctivitis.

CONCLUSIONS

Our empirical RGP CLs fitting philosophy presented that aphakic infant's age can be used to determine the initial lens if accurate biometry cannot be obtained initially.

The diluted atropine for inhibition of myopia progression in Korean children

AIM

To evaluate the efficacy and safety of three different concentrations of diluted atropine for the control of myopia in Korean children, and to assess the risk factors associated with rapid myopia progression.

METHODS

A total of 285 children, with refractive errors within the range of -6 diopters (D) between 5 and 14 years of age were included. After using 0.01%, or 0.025%, or 0.05% atropine, for about 1y, changes in refraction, axial lengths and frequency of adverse events were analyzed. Logistic regression analyses were performed to evaluate the risk factors associated with rapid myopia progression.

RESULTS

The changes in the mean spherical equivalent values were -0.134 D/mo in the before atropine group, -0.070 D/mo in the 0.01% atropine group, -0.047 D/mo in the 0.025% atropine group, and -0.019 D/mo in the 0.05% atropine group, with significant differences between the groups (P<0.001). The axial elongation was 0.046 mm/mo, 0.037 mm/mo, 0.025 mm/mo, and 0.019 mm/mo respectively, with significant differences between the groups (P=0.003). The incidence of photophobia and near vision difficulty was not different among the three atropine groups (P=0.425 and P=0.356, respectively). Multivariate logistic regression analyses showed that only highly myopic parents were a significant predictive factor of rapid myopia progression in Korean children (odds ratio, 8.155; 95% confidence interval, 3.626-18.342; P<0.001).

CONCLUSION

Treatment with 0.01%, 0.025% and 0.05% atropine solution inhibits myopia progression in Korean children in a dose-dependent manner. Children with highly myopic parents preferentially shows a rapid myopia progression rate.

Anisometropia at Age 5 Years After Unilateral Intraocular Lens Implantation During Infancy in the Infant Aphakia Treatment Study

PURPOSE

To report the prevalence of anisometropia at age 5 years after unilateral intraocular lens (IOL) implantation in infants.

DESIGN

Prospective randomized clinical trial.

METHODS

Fifty-seven infants in the Infant Aphakia Treatment Study (IATS) with a unilateral cataract were randomized to IOL implantation with an initial targeted postoperative refractive error of either +8 diopters (D) (infants 28 to <48 days of age) or +6 D (infants 48-210 days of age). Anisometropia was calculated at age 5 years. Six patients were excluded from the analyses.

RESULTS

Median age at cataract surgery was 2.2 months (interquartile range [IQR], 1.2, 3.5 months). The mean age at the age 5 years follow-up visit was 5.0 ± 0.1 years (range, 4.9-5.4 years). The median refractive error at the age 5 years visit of the treated eyes was -2.25 D (IQR -5.13, +0.88 D) and of the fellow eyes +1.50 D (IQR +0.88, +2.25). Median anisometropia was -3.50 D (IQR -8.25, -0.88 D); range -19.63 to +2.75 D. Patients with glaucoma in the treated eye (n = 9) had greater anisometropia (glaucoma, median -8.25 D; IQR -11.38, -5.25 D vs no glaucoma median -2.75; IQR -6.38, -0.75 D; P = .005).

CONCLUSIONS

The majority of pseudophakic eyes had significant anisometropia at age 5 years. Anisometropia was greater in patients that developed glaucoma. Variability in eye growth and myopic shift continue to make refractive outcomes challenging for IOL implantation during infancy.

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.

Human parallels to experimental myopia? A literature review on visual deprivation

Raviola and Wiesel's monkey eyelid suture studies of the 1970s laid the cornerstone for the experimental myopia science undertaken since then. The aim has been to clarify the basic humoral and neuronal mechanisms behind induced myopization, its eye tissue transmitters in particular. Besides acquiring new and basic knowledge, the practical object of the research is to reduce the burden of human myopia around the world. Acquisition and cost of optical correction is one issue, but associated morbidity counts more, with its global load of myopia-associated visual loss and blindness. The object of the present PubMed literature-based review is to evaluate apparent similarities between experience from disturbed imaging in experimental laboratory science and varieties within the spectrum of childhood human myopia. So far, the main impression is that macroscopical optical deprivation appears absent in the prevalent types of human myopia, nor is myopia a regular sequel where early eye pathology has led to poor imaging and optical deprivation. Optical aberrations of a higher order are a relatively new issue in myopia research, and microstructural deprivation is only marginally dealt within the survey. Links between experimental and human myopia appear mainly occasional, and with only few examples in humans where factual parallels appear credible. Clinical and epidemiological data on refraction remain important, in particular with a view to life style and environmental factors. Such knowledge may further serve as inspiration to the laboratory research, which aims at solving the basic enigmas on a tissue level.

The impact of intermittent exotropia and surgery for intermittent exotropia on myopic progression among early school-aged children with myopia

AIM

To investigate the relationship between myopic progression and intermittent exotropia, and the impact of surgery for exotropia on myopic progression in early school-aged children (from 7 years to 12 years of age).

METHODS

Medical records of early school-aged patients with myopia were reviewed. Patients were divided into three groups; (A) Patients with intermittent exotropia and myopia at presentation and who underwent bilateral lateral rectus muscle recession for exotropia when 7-12 years old; (B) Patients with intermittent exotropia and myopia at presentation and who were merely observed for exotropia; and (C) Patients with myopia and straight ocular alignment. Main outcome measurements were the simple rate of myopic progression per year, the preoperative and postoperative rates of refractive growth with regards to the logarithmic age model in Group A, and the rate of high myopia development at the end of the early school period.

RESULTS

The rates of myopic progression were -0.43±0.14 dioptre (D) per year in Group A, -0.49±0.17 D/year in Group B and -0.42±0.24 D/year in Group C. There was no significant difference in the rate of myopic progression among three groups. There was no significant intergroup difference in the preoperative and postoperative rates of refractive growth in Group A. There were no significant intergroup differences in the rates of high myopia development among three groups.

CONCLUSIONS

Whether patients with intermittent exotropia underwent surgical correction for intermittent exotropia did not influence the rate of myopic progression. There was no significant difference in the rate of myopic progression between patients with accompanying intermittent exotropia and myopia and those with myopia alone.

Solutions in pediatric cataracts

PURPOSE OF REVIEW

Modern pediatric cataract surgical techniques combined with a greater understanding of the natural history of aphakia and pseudophakia have changed the approach to the surgery of pediatric cataracts.

RECENT FINDINGS

Advanced surgical techniques, new pharmacologic options and long-term refractive planning have improved surgical success.

SUMMARY

It is essential that the ophthalmic surgeon who cares for children with cataracts is aware of these issues.

Predictability of intraocular lens power calculation formulae in infantile eyes with unilateral congenital cataract: results from the Infant Aphakia Treatment Study

PURPOSE

To compare accuracy of intraocular lens (IOL) power calculation formulae in infantile eyes with primary IOL implantation.

DESIGN

Comparative case series.

METHODS

The Hoffer Q, Holladay 1, Holladay 2, Sanders-Retzlaff-Kraff (SRK) II, and Sanders-Retzlaff-Kraff theoretic (SRK/T) formulae were used to calculate predicted postoperative refraction for eyes that received primary IOL implantation in the Infant Aphakia Treatment Study. The protocol targeted postoperative hyperopia of +6.0 or +8.0 diopters (D). Eyes were excluded for invalid biometry, lack of refractive data at the specified postoperative visit, diagnosis of glaucoma or suspected glaucoma, or sulcus IOL placement. Actual refraction 1 month after surgery was converted to spherical equivalent and prediction error (predicted refraction - actual refraction) was calculated. Baseline characteristics were analyzed for effect on prediction error for each formula. The main outcome measure was absolute prediction error.

RESULTS

Forty-three eyes were studied; mean axial length was 18.1 ± 1.1 mm (in 23 eyes, it was <18.0 mm). Average age at surgery was 2.5 ± 1.5 months. Holladay 1 showed the lowest median absolute prediction error (1.2 D); a paired comparison of medians showed clinically similar results using the Holladay 1 and SRK/T formulae (median difference, 0.3 D). Comparison of the mean absolute prediction error showed the lowest values using the SRK/T formula (1.4 ± 1.1 D), followed by the Holladay 1 formula (1.7 ± 1.3 D). Calculations with an optimized constant showed the lowest values and no significant difference between the Holladay 1 and SRK/T formulae (median difference, 0.3 D). Eyes with globe AL of less than 18 mm had the largest mean and median prediction error and absolute prediction error, regardless of the formula used.

CONCLUSIONS

The Holladay 1 and SRK/T formulae gave equally good results and had the best predictive value for infant eyes.

[Evaluation of predictability and refractive changes in pediatric pseudophakia]

OBJECTIVE

Evaluate the predictability of the postoperative refraction and refractive changes in pediatric pseudophakia.

METHODS

Prospective, longitudinal follow-up on patients under the age of 15 years operated on for a cataract with intraocular lens, with 5 continuous years of follow-up. The patients were divided into 4 groups according to age at the time of the surgery: group from 0 to 2 years old, from 3 to 5 years old, from 6 to 8 years old, and 9 years and over. Error prediction and refractive change were studied. Statistical analysis was performed using the Student t and ANOVA test.

RESULTS

A total of 60 eyes were included (44 patients). No significant differences were found between the unilateral and bilateral group. The prediction error in the 0 to 2 years group was 1.5±1.8 D, significantly higher than in the other groups (ANOVA P=.01). Refractive change in 5 years of the group of 0 to 2 years was -4.7±3.4 D (ANOVA P=.0002), while in the other groups it was significantly lower, with no differences between them.

CONCLUSIONS

The 0 to 2 years group was less hyperopic than expected, 100% within the accepted of 2 standard deviations, but with a high variability. The refractive change observed in this group coincides with previous reports that the largest growth and increase in axial length occurs during the first 2 years. The calculation and use of an IOL in children has a better immediate refractive prediction, and at long term in those older than 2 years of age.

Pediatric intraocular lens power calculations

PURPOSE OF REVIEW

To implant an appropriate intraocular lens (IOL) in a child, we must measure the eye well, calculate the IOL power accurately and predict the refractive change of the pseudophakic eye to maturity. The present review will concentrate on recent studies dealing with these issues.

RECENT FINDINGS

Immersion A-scan biometry is superior in measuring the axial length of children. Current IOL power calculation formulas are very accurate in adults, but significantly less accurate in children. Several studies point to the high prediction errors encountered particularly in shorter eyes with all available IOL formulas. Postoperative refraction target remains controversial, but low degrees of overcorrection (i.e. hyperopia) may not adversely affect eventual best-corrected visual acuity.

SUMMARY

Although pediatric IOL power calculations suffer from significant prediction error, these errors can be decreased by careful preoperative measurements. IOL power calculation formulas are most accurate in the older, more 'adult'-sized eye. The smallest eyes have the most prediction error with all available formulas. Individual circumstances and parental concerns must be factored into the choice of a postoperative refractive target.

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.

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.

Predictability of intraocular lens calculation and early refractive status: the Infant Aphakia Treatment Study

OBJECTIVE

To report the accuracy of intraocular lens (IOL) power calculations and the early refractive status in pseudophakic eyes of infants in the Infant Aphakia Treatment Study.

METHODS

Eyes randomized to receive primary IOL implantation were targeted for a postoperative refraction of +8.0 diopters (D) for infants 28 to 48 days old at surgery and +6.0 D for those 49 days or older to younger than 7 months at surgery using the Holladay 1 formula. Refraction 1 month after surgery was converted to spherical equivalent, and prediction error (PE; defined as the calculated refraction minus the actual refraction) and absolute PE were calculated. Baseline eye and surgery characteristics and A-scan quality were analyzed to compare their effect on PE.

MAIN OUTCOME MEASURES

Prediction error.

RESULTS

Fifty-six eyes underwent primary IOL implantation; 7 were excluded for lack of postoperative refraction (n = 5) or incorrect technique in refraction (n = 1) or biometry (n = 1). Overall mean (SD) absolute PE was 1.8 (1.3) D and mean (SD) PE was +1.0 (2.0) D. Absolute PE was less than 1 D in 41% of eyes but greater than 2 D in 41% of eyes. Mean IOL power implanted was 29.9 D (range, 11.5-40.0 D); most eyes (88%) implanted with an IOL of 30.0 D or greater had less postoperative hyperopia than planned. Multivariate analysis revealed that only short axial length (<18 mm) was significant for higher PE.

CONCLUSIONS

Short axial length correlates with higher PE after IOL placement in infants. Less hyperopia than anticipated occurs with axial lengths of less than 18 mm or high-power IOLs. Application to Clinical Practice Quality A-scans are essential and higher PE is common, with a tendency for less hyperopia than expected.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00212134.

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.