Choosing IOL power in pediatric cataract surgery

Myopic shift, refractive, and visual outcomes after 5 years of infantile cataract surgery: Our experience and review of literature

PURPOSE

After infantile cataract surgery, axial elongation, induces a myopic shift that cannot be fully compensated by corneal flattening and the rate is unpredictable owing to the non-linear growth of the eye. The current prospective study assesses the myopic shift and visual outcomes in children undergoing cataract surgery in infancy over a follow-up period of 5 years.

MATERIALS AND METHODS

A prospective study conducted at a tertiary eye care center to evaluate the five-year myopic shift, refractive and visual outcomes in infants, who underwent surgery for congenital cataract in infancy. The visual acuity, myopic shift and biometric changes are compared between the aphakia and pseudophakia group.

RESULTS

The mean best-corrected visual acuity (BCVA) recorded in logMAR at 5 years for aphakia group was 0.92±0.44 and for pseudophakia group was 0.66±0.42. (pvalue: 0.002102). The myopic shift was noted to be -5.9+/-5.16 in the aphakia group whereas it was -9.01+/- 3.11 in the pseudophakia group (P value= 0.002101) at 5 years after surgery for infantile cataract.

CONCLUSION

IOL implantation in eyes of infants undergoing cataract surgery is feasible in eyes that strictly satisfy the pre-operative inclusion criteria and the visual outcomes in these eyes are better compared to aphakia group at 5 years follow up. Eyes with primary IOL implantation had a higher myopic shift compared to ones without primary IOL implantation. Eyes undergoing primary IOL implantation, need higher under correction compared to the current available formulae.

A new strategy to calculate the intraocular lens power in congenital cataracts according to age and axial length at implantation

PURPOSE

The purpose of the study was to suggest a new method to calculate the intraocular lens (IOL) power in paediatric cataracts targeting emmetropia at the age of 15 years.

METHODS

Data of children younger than 15 years who underwent cataract surgery with IOL implantation between 2005 and 2020 in the ophthalmological department of Marseille (South of France) was collected retrospectively. A logarithmic regression model was used to predict the axial length growth of the included eyes between implantation and 15 years. The predicted myopic shift served as target refraction to calculate a theoretical IOL power aiming for emmetropia at 15 years. Refractive error with the theoretical lens power was estimated as the spherical equivalent at the last follow-up minus the difference of target refractions between the implanted IOL and the theoretical one. Refractive errors using Dahan, Enyedi and Trivedi guidelines were also estimated and compared to the logarithmic model.

RESULTS

Thirty-five eyes of 26 children were analysed. At the last follow-up, the median age of children was 10 years old and the median spherical equivalent was -1.88 dioptres (D) (IQR -3.81, -0.75). The estimated median refractive errors were 0.18 D (IQR -1.11, 1.42) with the logarithmic formula, -1.47 D (IQR -3.84, -0.65) with Dahan formula, -0.63 D (IQR -2.15, 0.32) with Enyedi formula and 0.38 D (IQR -1.58, 1.07) with Trivedi formula.

CONCLUSION

The estimated refractive error with the new logarithmic formula is the closest to emmetropia at the last follow-up.

Congenital Cataracts in Preterm Infants: A Review

A congenital cataract is one of the most treatable causes of visual impairment during infancy. Preterm infants who are born alive before 37 weeks of pregnancy need special care, including proper age documentation, preoperative assessment, and monitoring postoperatively for at least 24 hours. Management of cataracts in preterm infants is critical as regards the timing of cataract surgery and the challenges associated with cataract surgery and posterior segment management for retinopathy of prematurity (ROP). This narrative review aims to provide comprehensive insight and up-to-date clinical research findings regarding the pathophysiology and management of congenital cataracts in preterm infants.

Accuracy of the SRK/T Formula in Pediatric Cataract Surgery

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.].

Biometric changes in Indian pediatric cataract and postoperative refractive status

Purpose:

To prospectively evaluate the biometric changes in Indian pediatric cataract and postoperative refractive status.

Methods:

A total of 147 patients were recruited into three groups: age <6 months, age between 7 months and 18 months, and age between 19 and 60 months and prospectively observed for 6 months. Exclusion criteria were preterm birth, microphthalmia, microcornea, megalocornea, uveitis, glaucoma, and traumatic or complicated cataract. Axial length and keratometry, the primary outcome measures, were taken preoperatively under general anesthesia before surgery. These children were followed up for 6 months to look for refractive and biometric changes. T-test and linear regression with the logarithm of independent variables were done.

Results:

All unilateral cataractous eyes (n = 25) and randomly selected bilateral cases (n = 122) were included in the analysis, for a total of 147 eyes. Mean age was 17.163 ± 13.024 months; axial length growth was 0.21, 0.18, 0.06 mm/month, and keratometry decline was 0.083, 0.035, 0.001 D/month in age groups 0–6, 7–18, and 19–60 months, respectively. The visual acuity improved in log MAR from 1.020 to 0.745 at 6 months postoperatively. There was statistically significant (Spearman's correlation coefficient = –0.575, P < 0.001) between age and postoperative refraction. There were no intraocular lens (IOL)-related complications seen in the immediate postoperative period. Peripheral opacification was seen in 102 eyes and central opacification in 1 eye at a 6-month follow-up.

Conclusion:

Indian eyes have a lower rate of axial length growth and keratometry change in comparison with western eyes implying smaller undercorrection in emmetropic IOL power for Indian pediatric eyes to achieve a moderate amount of hyperopia.

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.

Myopic Shift 5 Years after Intraocular Lens Implantation in the Infant Aphakia Treatment Study

PURPOSE

To report the myopic shift at 5 years of age after cataract surgery with intraocular lens (IOL) implantation for infants enrolled in the Infant Aphakia Treatment Study (IATS).

METHODS

Refractions were performed at 1 month and every 3 months postoperatively until age 4 years and then at ages 4.25, 4.5, and 5 years. The change in refraction over time was estimated by linear mixed model analysis.

RESULTS

Intraocular lens implantation was completed in 56 eyes; 43 were analyzed (median age, 2.4 months; range, 1.0-6.8 months). Exclusions included 11 patients with glaucoma, 1 patient with Stickler syndrome, and 1 patient with an IOL exchange at 8 months postoperatively. The mean rate of change in a myopic direction from 1 month after cataract surgery to age 1.5 years was 0.35 diopters (D)/month (95% confidence interval [CI], 0.29-0.40 D/month); after age 1.5 years, the mean rate of change in a myopic direction was 0.97 D/year (95% CI, 0.66-1.28 D/year). The mean refractive change was 8.97 D (95% CI, 7.25-10.68 D) at age 5 years for children 1 month of age at surgery and 7.22 D (95% CI, 5.54-8.91 D) for children 6 months of age at surgery. The mean refractive error at age 5 years was -2.53 D (95% CI, -4.05 to -1.02).

CONCLUSIONS

After IOL implantation during infancy, the rate of myopic shift occurs most rapidly during the first 1.5 years of life. Myopic shift varies substantially among patients. If the goal is emmetropia at age 5 years, then the immediate postoperative hypermetropic targets should be +10.5 D at 4 to 6 weeks and +8.50 D from 7 weeks to 6 months. However, even using these targets, it is likely that many children will require additional refractive correction given the high variability of refractive outcomes.

Cataract

Cataract is the leading cause of reversible blindness and visual impairment globally. Blindness from cataract is more common in populations with low socioeconomic status and in developing countries than in developed countries. The only treatment for cataract is surgery. Phacoemulsification is the gold standard for cataract surgery in the developed world, whereas manual small incision cataract surgery is used frequently in developing countries. In general, the outcomes of surgery are good and complications, such as endophthalmitis, often can be prevented or have good ouctomes if properly managed. Femtosecond laser-assisted cataract surgery, an advanced technology, can automate several steps; initial data show no superiority of this approach over current techniques, but the results of many large clinical trials are pending. The greatest challenge remains the growing 'backlog' of patients with cataract blindness in the developing world because of lack of access to affordable surgery. Efforts aimed at training additional cataract surgeons in these countries do not keep pace with the increasing demand associated with ageing population demographics. In the absence of strategie that can prevent or delay cataract formation, it is important to focus efforts and resources on developing models for efficient delivery of cataract surgical services in underserved regions. For an illustrated summary of this Primer, visit: http://go.nature.com/eQkKll.

Multi-component adjustable intraocular lenses: a new concept in pediatric cataract surgery

PURPOSE

The multi-component intraocular lens (IOL) (IVO; SAS, Strasbourg, France) is a novel approach to the treatment of pediatric cataract. Because the refractive requirements for pediatric eyes often change over time, current IOL technology does not easily allow refractive adjustments after the primary surgical intervention. The multi-component IOL concept allows easy, surgical refractive adjustments to the initial surgical implantation at any postoperative time period. Thus, both surgical implantation and enhancement surgery have been successfully accomplished in adult patients.

METHODS

A novel surgical approach to pediatric cataract surgery is described. At the time of the primary surgery, a two component IOL was implanted. At any postoperative time period, the front lens component, located in front of the capsular bag, could be easily surgically exchanged because the dioptric power requirements of the pediatric eye changed over time.

RESULTS

Both primary and enhancement surgeries have been done in adult patients with good results. Implantations have occurred uneventfully in all cases with no intraoperative or postoperative complications. There was no statistically significant difference in the endothelial cell density, anterior chamber depth, and pachymetry readings preoperatively and 2 years postoperatively. There was no interlenticular fibrosis present.

CONCLUSION

The multi-component IOL should provide a unique and greatly needed surgically adjustable approach to the treatment of pediatric cataract.

Visual outcome of cataract in pediatric age group: does etiology have a role

PURPOSE

To compare visual outcome results among traumatic and nontraumatic groups of eyes with cataract in the pediatric age group.

METHOD

This is a retrospective cohort study. This study comprised a consecutive series of pediatric patients under 5 years of age with unilateral congenital, developing, or traumatic cataract who underwent surgery between January 1999 and April 2012 at Drashti Netralaya, Dahod. Records were retrieved from the medical record department. Patients were grouped as traumatic or nontraumatic and their demographics, cataract type, presenting symptoms, surgical intervention, and postoperative visual acuity follow-up refractive changes were recorded and compared.

RESULTS

A total of 128 eyes of 128 children under 5 years of age were included with unilateral cataract. A total of 85 (66.4%) were traumatic and 43 (33.3%) nontraumatic. The age at surgery ranged from 1 to 60 months. Eyes were grouped by etiology: group 1- traumatic 85 (66.4%) eyes that had traumatic cataracts. Group 2 non-traumatic 43 (33.3%) eyes that had congenital, developmental or complicated cataracts. The mean follow-up time was 117 days. Finally, 22 (51.1%) group 1 patients and 40 (47.1%) group 2 patients achieved visual acuity better than 20/200 (p = 0.000).

CONCLUSIONS

Surgical treatment with intraocular lens implantation for children with congenital, developmental, or traumatic cataract is an effective treatment for visual rehabilitation. Visual outcome is significantly better (p = 0.005) in case of nontraumatic cataracts than traumatic cataracts.

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 accuracy after intraocular lens implantation in pediatric cataract

AIM

To analyze the factors that influence the prediction error (PE) after intraocular lens (IOL) implantation in pediatric cataract.

METHODS

The medical records of cataract patients of no more than 14 years old who had primary IOL implantation were reviewed from 2006 to 2010. The PE, absolute value of PE (APE), and predictability between in different axial length, mean corneal curvature, corneal astigmatism, and age at the surgery were analyzed.

RESULTS

Seventy-five children (119 eyes) were included, with a mean age of (5.09±2.54) years. At the follow-up of (1.19±0.69) months, the mean postoperative PE was (-0.22±1.12) D, and APE was (0.87±0.73)D. The PE in eyes with an axial length >20mm but ≤22mm were significantly under-corrected than that in eyes with longer axis, and the APE in eyes with an axial length ≤20mm was more obvious compared with the others. The correlations between PE and axial length, as well as corneal astigmatism, and between APE and axial length were significant. The predictability was significantly poorer in the eyes with an axial length ≤20mm than the others.

CONCLUSION

The axial length is closely related with the PE after IOL implantation in pediatric cataract patients, especially when it is ≤20mm, PE is more significant. The formula that is more suitable to very short axial length should be explored.

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.