Refractive surgery in children: treatment options, outcomes, and controversies

Refractive Surgery in Myopic Children

In this paper, we summarize the current knowledge on refractive surgery performed in the myopic pediatric population. We describe the main concerns about refractive surgery in myopic children and the indications for refractive surgery in this age group. We present a range of surgical procedures that are being used for the management of unilateral/bilateral myopia in children: corneal refractive surgery (PRK, LASEK, LASIK, FS-LASIK and SMILE) and intraocular refractive surgery (phakic intraocular lens implantation, refractive lens exchange or clear lens extraction), with both their advantages and drawbacks. We also describe the various complications and measures to prevent them.

Pediatric refractive surgery: current opinion in ophthalmology

PURPOSE OF REVIEW

Pediatric refractive surgery has been growing at a steady pace since its introduction in the early 1980 s. This article will review common laser refractive surgeries performed on pediatric patients along with controversies regarding the practice.

RECENT FINDINGS

Pediatric refractive surgery is reserved for a small population of children who fail amblyopic treatment due to high anisometropic refractive errors. Publications over the years have treated these children with various types of laser refractive surgery.

SUMMARY

Laser pediatric refractive surgery appears to be well tolerated and effective for the population of children that need it. It provides an alternative for anisometropic amblyopia treatment for children who would have otherwise not been able to improve their vision.

National estimate and associated factors of myopia among schoolchildren in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Myopia is a global public health concern that has a significant socioeconomic and psychological impact on schoolchildren. If Myopic patients are not detected early, they are exposed to retinal detachment, cataracts, and glaucoma. There have been previous studies conducted in Ethiopia, but there is significant inconsistency among studies. Hence, the aim of this study was to provide a single figure as well as associated factors for Myopia among Ethiopian schoolchildren.

METHOD

The national and international databases and gray literature were searched for important research articles. This review included school-based cross-sectional studies that were reported in English. The data were extracted using Microsoft word and exported to Stata™ Version 17.0 statistical software for further management and analysis .The presence of heterogeneity was checked using Cochrane Q test via fixed effects model and presented by forest plots with 95% CI. Due to the presence of substantial heterogeneity, I2 test using random effects model was computed to estimate the effect size. The existing heterogeneity among studies was explained by regional difference. To identify factors associated with myopia, meta regression was computed and significant factors was reported using OR with 95% CI.

RESULTS

In this systematic review and meta-analysis, 12 studies with a total of 9688 schoolchildren were included. The national estimate of myopia among schoolchildren in Ethiopia was 6.49% (95%CI: 4.86, 8.12). Having family history of myopia (OR: 9.18, 95%CI: 3.5,24.02) and being female (OR: 0.94, 95% CI: 0.50, 0.98) were the identified factors associated with myopia.

CONCLUSION

Myopia is one of the most prevalent childhood health condition in Ethiopia, which affects about one in every fourteen schoolchildren. Schoolchildren who had family history of myopia and being female were the identified risk factors of myopia among schoolchildren. Clinical and public engagement activities are needed to address the burden of myopia.

Refractive surgery as a treatment tool for strabismus: systematic review

The impact refractive surgery has on preoperative horizontal strabismus is rapidly evolving, and this knowledge can provide valuable clinical context when considering refractive surgery as a treatment for strabismus. 515 studies were identified, of which 26 met the inclusion criteria. Analysis indicated that refractive surgery resulted in an overall decrease in the mean uncorrected postoperative angle of deviation caused partially or fully due to refractive error and highlighted the varied outcome of refractive surgery on nonaccommodative horizontal strabismus with limited evidence to suggest refractive surgery for this type of strabismus. Efficacy of refractive surgery in reducing concomitant horizontal strabismus depends on several factors: type of horizontal ocular deviation, patient age, and extent of refractive error. Refractive surgery can be an effective treatment for refractive accommodative horizontal strabismus in patients with stable, mild to moderate myopia or hyperopia and should be considered with careful patient selection for optimum outcome.

IMI-Management and Investigation of High Myopia in Infants and Young Children

Purpose

The purpose of this study was to evaluate the epidemiology, etiology, clinical assessment, investigation, management, and visual consequences of high myopia (≤-6 diopters [D]) in infants and young children.

Findings

High myopia is rare in pre-school children with a prevalence less than 1%. The etiology of myopia in such children is different than in older children, with a high rate of secondary myopia associated with prematurity or genetic causes. The priority following the diagnosis of high myopia in childhood is to determine whether there is an associated medical diagnosis that may be of greater overall importance to the health of the child through a clinical evaluation that targets the commonest features associated with syndromic forms of myopia. Biometric evaluation (including axial length and corneal curvature) is important to distinguishing axial myopia from refractive myopia associated with abnormal development of the anterior segment. Additional investigation includes ocular imaging, electrophysiological tests, genetic testing, and involvement of pediatricians and clinical geneticists is often warranted. Following investigation, optical correction is essential, but this may be more challenging and complex than in older children. Application of myopia control interventions in this group of children requires a case-by-case approach due to the lack of evidence of efficacy and clinical heterogeneity of high myopia in young children.

Conclusions

High myopia in infants and young children is a rare condition with a different pattern of etiology to that seen in older children. The clinical management of such children, in terms of investigation, optical correction, and use of myopia control treatments, is a complex and often multidisciplinary process.

Impact of Ocular Conditions and Improvements After Refractive Surgery in Quality of Life for Children With Neurodevelopmental Disorders

PURPOSE

This study aims to characterize the eye-related quality of life of children with neurodevelopmental and ocular disorders at baseline and after refractive surgery.

DESIGN

Prospective interventional case series.

METHODS

We enrolled children and adolescents 5 to 18 of age with neurodevelopmental disorders undergoing refractive surgery (6 for pre-/postsurgical assessment and 14 for baseline analysis). Eye-related quality of life was measured using the Pediatric Eye Questionnaire (PedEyeQ). Baseline levels of adaptive functioning and social behaviors were measured using the Adaptive Behavioral Assessment System (ABAS-3) and Social Responsiveness Scale (SRS-2). We assessed the correlation between baseline PedEyeQ scores, number of ocular comorbidities, magnitude of refractive error, and ABAS-3 and SRS-2 scores.

RESULTS

At baseline, 14 patients demonstrated decreased median eye-related quality of life (<60/100) in 5 of 9 PedEyeQ domains, moderate deficiencies in social behaviors (SRS-2 median 71, range 49-90), and low adaptive functioning (ABAS-3 median percentile for age of 0.100). Baseline PedEyeQ scores did not correlate with magnitude of refractive error or adaptive functioning scores but did correlate with number of ocular comorbidities and social behavior scores. Six patients have undergone refractive surgery without complication. Postoperatively, 11 of 11 eyes were within ±1.5 diopters spherical equivalent. Four of 6 patients exhibited clinically significant improvements in PedEyeQ scores after surgery.

CONCLUSIONS

Even in the presence of significant social and adaptive impairments, quality of life in children with neurodevelopmental disorders is decreased by ocular disorders. Refractive surgery is associated with clinically significant improvements in eye-related quality of life.

Update on contraindications in laser corneal refractive surgery

More than 25 years of experience with refractive surgery techniques (since the FDA [Food and Drug Administration] of the United States approved the use of the excimer laser in the remodeling of the cornea in 1995), added to the technological advances in ophthalmology (femtosecond laser, topography-guided ablation, anterior segment imaging systems) and increased understanding of refractive errors, higher order aberrations, and corneal biomechanics make corneal laser refractive surgery a safe method and effective for the correction of these defects. However, to date, there are still certain circumstances that represent a contraindication for its application, in addition to others that could be associated with complications, and that must be carefully analyzed. This review analyzes the current contraindications for laser corneal refractive surgery listed in the Preferred Practice Protocols (PPPs) of the American Academy of Ophthalmology and the Spanish Ophthalmology Society. These protocols are based on the best scientific evidence currently available and allow clear recommendations to be drawn, improving the safety profile of these techniques. Contraindications can be differentiated into relative or absolute; among the latter are: age less than 18 years, the absence of refractive stability and the existence of certain ocular pathologies (including certain corneal dystrophies, keratoconus, poorly controlled dry eye) or systemic pathologies (active autoimmune processes or poorly controlled diabetes mellitus). Other circumstances such as the use of certain drugs (amiodarone, isotretinoin), extreme values of mean central keratometry and pachymetry, history of previous uveitis or glaucoma, pregnancy and lactation, are considered relative contraindications according to the PPPs. However, there are studies that demonstrate the safety of refractive surgery in some of these cases.

Myopia: Mechanisms and Strategies to Slow Down Its Progression

This topical review aimed to update and clarify the behavioral, pharmacological, surgical, and optical strategies that are currently available to prevent and reduce myopia progression. Myopia is the commonest ocular abnormality; reinstated interest is associated with high and increasing prevalence, especially but not, in the Asian population and progressive nature in children. The growing global prevalence seems to be associated with both genetic and environmental factors such as spending more time indoor and using digital devices, particularly during the coronavirus disease 2019 pandemic. Various options have been assessed to prevent or reduce myopia progression in children. In this review, we assess the effects of several types of measures, including spending more time outdoor, optical interventions such as the bifocal/progressive spectacle lenses, soft bifocal/multifocal/extended depth of focus/orthokeratology contact lenses, refractive surgery, and pharmacological treatments. All these options for controlling myopia progression in children have various degrees of efficacy. Atropine, orthokeratology/peripheral defocus contact and spectacle lenses, bifocal or progressive addition spectacles, and increased outdoor activities have been associated with the highest, moderate, and lower efficacies, respectively.

Visual outcomes of photorefractive keratectomy in non-children with anisometropic amblyopia: One-year Follow-up Outcomes

OBJECTIVE

To evaluate the safety, efficiency, short term stability, and sensory results of photorefractive keratectomy (PRK) in anisometropic in non-compliant children with correction.

METHODS

Twelve eyes of 12 children with an age range: 6-17 years and anisometropic amblyopia who underwent PRK under general anesthesia to correct the dioptric difference between the eyes were included in this study. A complete ophthalmic assessment including refractive status, uncorrected and corrected distance visual acuity (UDVA & CDVA), and binocular vision status using the Worth 4-dot test and stereopsis were performed before and 1, 3, 6, and 12 months after PRK.

RESULTS

The mean preoperative CDVA was 0.34 ± 0.24 LogMAR which showed a statistically significant improvement at 12 months (0.20 ± 0.19, p = 0.024) after surgery compared to the preoperative assessment. (p = 0.003) The mean preoperative UDVA was 0.63 ± 0.24 LogMAR that increased to 0.44 ± 0.24, 0.32 ± 0.16, 0.25 ± 0.19, and 0.25 ± 0.19 LogMAR at 1, 3, 6, and 12 months after PRK, respectively. One to three lines improvement in UDVA and CDVA was seen in 10 (83.4%) and 8 eyes (66.7%); while one line UDVA and CDVA loss was seen in one (8.3%) and one (8.3%) eye and unchanged UDVA and CDVA was seen in 1 (8.3%) and 3 eyes (25%), respectively. The mean preoperative stereoacuity was 341.9 ± 245.7 s of arc, which significantly improved to 166.6 ± 87.5 s of arc 12 months after PRK. (p = 0.012).

CONCLUSION

PRK was an effective surgical alternative to improve visual acuity and stereopsis in anisometropic children who did not cooperate with conventional methods of amblyopia therapy.

Stereopsis after corneal refractive surgeries: a systematic review and meta-analysis

PURPOSE

To systematically review the published manuscripts on stereopsis after corneal refractive surgery.

METHODS

The Web of Science, PubMed, Scopus, ProQuest, Clinical Key, Embase, and Cochrane Library were searched for relevant articles published until August 2020. The fixed- or random-effects models were used to estimate the Weighted mean difference (WMD) or Relative risk (RR) and 95% Confidence interval (CI) for postoperative stereopsis changes and incidence when applicable. Meta-regression was conducted for adjusting the effects of potential confounders.

RESULTS

Seven studies (1266 eyes) in adults and ten studies in pediatrics (259 eyes) were included. In adults, stereopsis improved significantly compared to the preoperative state (WMD = - 27.4, 95% CI = - 40.0, - 14.7; I² = 97.8%; P < 0.001). In pediatrics, proportion of patients with stereoacuity postoperatively was 2.18 times compared to preoperative evaluation. (RR = 2.18, 95% CI = 1.2, 3.9; I² = 68.6%, P < 0.001).

CONCLUSIONS

Stereopsis improves after corneal refractive surgery in adults and pediatrics.

Overcoming myopic shift by the initial inductive hypermetropia in pediatric cataract surgery

Purpose:

To assess the outcome of under-correction of intraocular lens (IOL) power in pediatric cataract surgery.

Methods:

We collected clinical data of 103 patients (181 eyes), all aged ≤15 years, who had undergone cataract surgery by a surgeon during 2006–2016. The mean duration of follow-up was 73 ± 38 months (range: 24–108). IOL power was calculated by Hoffer Q formula in axial length (AL) <21 mm and SRKT formula in AL ≥21 mm and then modified based on this approach: 7D initial inductive hypermetropization in children ≤1-year-old, 5D in 1–3, 3.5D in 3–5, 2.5D in 5–7, 1.5D in 7–9, 1D in 9–10, and 0 in children >10 years old.

Results:

The mean age of all children at surgery time was 5.85 ± 4.56 years (range: 1–178 months). There was a mean myopic shift of −6.379 D in the ≤1 year, −5.532 in the 1–3, −3.194 in the 3–5, −2.301 in the 5–7, −1.06 in the 7–9, −1.567 in the 9–10, and 0.114 in the >10-year-old age group. In 125 eyes (69.1%) of 181, the final SE was between −2 and +2 D, and 21 eyes (11.6%) achieved the goal of emmetropization. Mean best-corrected visual acuity logarithm of the minimum angle of the resolution was 0.30 in children ≤1 year, 0.39 in 1–3, 0.21 in 3–5, 0.18 in 5–7, 0.14 in 7–9, 0.16 in 9–10, and 0.11 in children >10 years old.

Conclusion:

This study shows a larger myopic shift in younger children. Using our approach, all age groups could finally achieve acceptable final refraction.

Effect of ancillary drugs on sevoflurane related emergence agitation in children undergoing ophthalmic surgery: a Bayesian network meta-analysis

BACKGROUND

The comparative efficacy of ancillary drugs on sevoflurane related emergence agitation (EA) in children undergoing ophthalmic surgery remains controversial.

METHODS

The databases were retrieved in an orderly manner from the dates of their establishment to October, 2018, including PubMed, The Cochrane Library and Web of Science, to collect randomized controlled trials (RCT) of different anesthetic drugs combined with sevoflurane for ophthalmic surgery. Then a network meta-analysis was conducted using R and Stata 12.0 softwares.

RESULTS

The meta-analysis showed that, in reducing sevoflurane related EA, dexmedetomidine, ketamine, propofol, fentanyl, midazolam, sufentanil, remifentanil and clonidine were superior to placebo (P < 0.05). The network meta-analysis showed that the effects of ancillary drugs combine with sevoflurane in reducing risk of EA in children undergoing ophthalmic surgery was superior to placebo: dexmedetomidine (OR = 0.17, 95% CrI 0.12-0.22), ketamine (OR = 0.30, 95% CrI 0.11-0.49), propofol (OR = 0.24, 95% CrI 0.09-0.63), fentanyl (OR = 0.16, 95% CrI 0.08-0.56), midazolam (OR = 0.20, 95% CrI 0.09-0.40), sufentanil (OR = 0.27, 95% CrI 0.14-0.41), remifentanil (OR = 0.18, 95% CrI 0.08-0.54) and clonidine (OR = 0.14, 95% CrI 0.07-0.41). The SUCRA of placebo, dexmedetomidine, ketamine, propofol, fentanyl, midazolam, sufentanil, remifentanil, clonidine were respectively 0.26, 77.93, 27.71, 42.8, 69.43, 52.89, 59.83, 57.62 and 61.53%.

CONCLUSIONS

The effects of dexmedetomidine combine with sevoflurane in reducing risk of emergence agitation in children undergoing ophthalmic surgery was superior to other drugs.

Corneal indices following photorefractive keratectomy in children at least 5 years after surgery

PURPOSE

To evaluate long-term corneal outcomes in pediatric patients who underwent photorefractive keratotomy (PRK) for the treatment of refractive amblyopia.

METHODS

In this prospective interventional case series, children with refractive amblyopia underwent PRK between January 1, 2007, and December 31, 2011, at Texas Children's Hospital's Department of Ophthalmology, a single tertiary eye center, and were followed for at least 5 years after surgery. Main outcome measures were 5+ years postoperative indices of corneal thickness, keratometry, degree of corneal haze, and presence or absence of keratectasia.

RESULTS

Twelve eyes of 8 subjects aged 3-9 years who underwent PRK and were followed for at least 5 years were included. The mean PRK treatment dose was 8.46 D for the myopic cohort and 4.49 D for the hyperopic cohort, which removed an average of 72 μm of corneal stromal tissue in addition to the 50 μm of corneal epithelium that was removed prior to laser ablation. The mean corneal thickness was 563 μm preoperatively, which decreased to 441 μm immediately following the PRK. The mean corneal thickness 5+ years after PRK was stable, at 498 μm, because of epithelial regrowth. None of the subjects developed visually significant corneal haze or topographic evidence of keratectasia.

CONCLUSIONS

In this study cohort, there were no topographic signs of keratectasia or corneal haze in children treated with PRK for high refractive error 5 years or more after surgery.

Long-term Effects After Pediatric LASIK for Anisometropic Amblyopia in Two Patients

PURPOSE

To report long-term follow-up of two pediatric patients who underwent laser in situ keratomileusis (LASIK) for myopic anisometropic amblyopia.

METHODS

Case series.

RESULTS

Two patients who underwent unilateral LASIK in 1999 for anisometropic amblyopia were clinically assessed 16 years after their initial procedure with visual acuity testing, refraction, stereopsis, axial length, corneal topography, slit-lamp examination, and quality of life assessment. Patients had stable corrected distance visual acuity, balanced refraction, improved stereopsis, and good visual quality of life. Corneal topography showed a mildly decentered ablation bed with no evidence of ectasia.

CONCLUSIONS

LASIK in the pediatric population requires special considerations, including fixation and centration issues, microkeratome selection, and refractive endpoint. The two patients were found to have stable corneal topography, visual acuity, and stereopsis 16 years after initial treatment. [J Refract Surg. 2019;35(6):391-396.].

New advances in amblyopia therapy II:

The treatment of anisometropic or ametropic amblyopia has traditionally enjoyed a high treatment success rate. Early initiation and consistent use of spectacle correction can completely resolve amblyopia in a majority of patients. For those with anisometropic amblyopia that fail to improve with glasses wear alone, patching or atropine penalisation can lead to equalisation of visual acuity. However, successful treatment requires full-time compliance with refractive correction and this can be a challenge for a patient population that often has one eye with good acuity without correction. Other barriers for a select population with high anisometropic  or ametropic amblyopia include rejection of glasses for various reasons including discomfort, behavioural or sensory problems, postural issues and visually significant aniseikonia. When consistent wear of optical correction proves difficult and patching/atropine remains a major obstacle, surgical correction of refractive error has proven success in achieving vision improvement. Acting as a means to achieve spectacle independence or reducing the overall needed refractive correction, refractive surgery can offer a unique treatment option for this patient population. Laser surgery, phakic intraocular lenses and clear lens exchange are three approaches to altering the refractive state of the eye. Each has documented success in improving vision, particularly in populations where glasses wear has not been possible. Surgical correction of refractive error has a risk profile greater than that of more traditional therapies. However, its use in a specific population offers the opportunity for improving visual acuity in children who otherwise have poor outcomes with glasses and patching/atropine alone.

Relative peripheral refraction across 4 meridians after orthokeratology and LASIK surgery

Background

To characterize the axial and off-axis refraction across four meridians of the retina in myopic eyes before and after Orthokeratology (OK) and LASIK surgery.

Methods

Sixty right eyes with a spherical equivalent (M) between − 0.75 to − 5.25 D (cylinder <− 1.00 D) underwent LASIK (n = 26) or OK (n = 34) to treat myopia. Axial and off-axis refraction were measured with an open-field autorefractometer before and after stabilized treatments. Off-axis measurements were obtained for the horizontal (35° nasal and temporal retina) and vertical (15° superior and inferior retina) meridians, and for two oblique directions (45–225° and 135–315°) up to 20° of eccentricity. The refractive profile was addressed as relative peripheral refractive error (RPRE).

Results

OK and LASIK post-treatment results showed an increase of myopic relative refraction at several eccentric locations. At the four meridians evaluated, the M component of the pre-treatment RPRE values was not statistically different (p > 0.05) from the post-treatment RPRE within 30° and 20° of the central visual field after LASIK and OK, respectively. These results demonstrated that the treatment zone warrants an optimal central field of vision.

Conclusions

The present study gives an overview of RPRE after refractive corneal reshaping treatments (OK and LASIK) across vertical, horizontal and two oblique meridians together. This allows a 3D representation of RPRE at the retina and shows that the myopic shift induced by both treatments is more relevant in horizontal directions.

Analysis of Macular and Retinal Nerve Fiber Layer Thickness in Children with Refractory Amblyopia after Femtosecond Laser-assisted Laser In situ Keratomileusis: A Retrospective Study

Background:

Localized macular edema and retinal nerve fiber layer (RNFL) thinning have been reported shortly after laser in situ keratomileusis (LASIK) in adults. However, it is still unclear how LASIK affects the retina of children. This study aimed to investigate the macular retina and RNFL thickness in children with refractive amblyopia who underwent femtosecond laser-assisted LASIK (FS-LASIK).

Methods:

In this study, we included 56 eyes of 32 patients with refractive amblyopia who underwent FS-LASIK in our hospital from January 2012 to December 2016. Foveal (foveal center retinal, parafoveal retinal, and perifoveal), macular inner retinal (superior and inferior), and peripapillary RNFL thicknesses (superior, inferior, temporal, and nasal) were measured using Fourier-domain optical coherence tomography before surgery and 1 day, 3 days, and 1 week after surgery. We divided these patients into three groups based on their refractive error: High myopic group with 22 eyes (equivalent sphere, >6.00 D), mild myopic group with 19 eyes (equivalent sphere, 0–6.00 D), and hyperopic group with 15 eyes (equivalent sphere, >+0.50 D). We compared the macular retina and RNFL thickness before and after LASIK. A paired simple t-test was used for data analysis.

Results:

One week after surgery, the visual acuity for all 56 eyes of the 32 patients reached their preoperative best-corrected vision. Visual acuity improved two lines or better for 31% of the patients. The residual refractive errors in 89% of the patients were within ±0.5 D. In the high myopic group, the foveal center retinal and parafoveal retinal thicknesses were thicker 1 day and 3 days after surgery than before surgery (t = 2.689, P = 0.012; t = 2.383, P = 0.018, respectively); no significant difference was found 1 week after surgery (P > 0.05). The foveal center retinal and parafoveal retinal thicknesses were greater 1 day after surgery than they were before surgery (P = 0.000 and P = 0.005, respectively) in the mild myopic and hyperopic groups. No significant difference was found 3 days or 1 week after surgery (P > 0.05). In all three groups, no significant difference was found in the macular inner retinal or peripapillary RNFL thickness 1 day, 3 days, or 1 week after surgery (P > 0.05).

Conclusions:

The foveal center retinal edema after FS-LASIK is mild and reversible in children, that mostly occurred in the high myopic group with no effect on the visual acuity, and is always relieved within 1 week.

[Axial ametropias of very high degree]

To characterize a complex of disorders developing in patients with extreme values of anteroposterior axis of the eye, it is necessary to create an appropriate nomenclature. As a topic for discussion, authors suggest to supplement the existing classifications of myopia and hyperopia with 'character of ametropia' section (axial, refractive, mixed) and the definition of ametropias of very high (ultra-high/extreme) degree (a criterion for myopia is: <-10 D). In prospect, classification of such ametropias should be based on the length of the anteroposterior axis of the eye.

V4B implantable collamer lens versus Intacs corneal rings to manage anisometropic myopic amblyopia in children

OBJECTIVE

To compare the safety and efficacy of phakic intraocular lens (PIOL) versus intrastromal corneal ring segments (Intacs), for correcting high myopic anisometropia in amblyopic children.

DESIGN

Nonrandomized prospective multi-center study.

PARTICIPANTS

Thirty children, aged between 4 and 12 years, with unilateral high myopic anisometropic amblyopia were included in this study.

METHODS

Patients who were prospectively subdivided into group A, with mean preoperative manifest refraction spherical equivalent (MRSE) of -12.96 ± 4.17 D, underwent unilateral phakic posterior chamber intraocular lens implantation. Patients with mean preoperative MRSE of -8.60 ± 1.16 D in group B were treated by Intacs corneal rings. Pre- and postoperative visual acuity, ocular examination, stereoacuity, axial biometry measurements, cycloplegic refraction, and endothelial cell counts were performed in all patients.

RESULTS

Group A revealed prevention of amblyopia with improvement in spectacle-corrected distance visual acuity, where 4-6 lines were achieved in 77% of children, 2-3 lines in 4%, and just 0-1 lines restricted to 19% of children. Improvement in stereoacuity was noted in 93.33% of group A cases, whereas group B showed fewer cases of successfully improved vision, with 4-6 lines in 70% of children, 2-3 lines in 3%, and just 0-1 lines restricted to 27% of children. Improvement in stereoacuity was noted in 86.66% of cases. Two cases of cataract and 1 case of glaucoma with 1 case of uveitis were noted in the implantable contact lens (ICL) group.

CONCLUSIONS

Posterior chamber PIOLs or Intacs may provide a safe alternative in treating anisometropic myopic patients. Intacs implantation is safer with fewer complications than ICL. However, ICL implantation is advantageous over the corneal ring segment procedure owing to the wide range of errors to correct.

Management of pseudophakic myopic anisometropic amblyopia with piggyback Visian® implantable collamer lens

PURPOSE

To assess the outcomes of sulcus implantation of the Visian^® implantable collamer lens (ICL) to correct pseudophakic myopic anisometropic amblyopia with myopic shift and/or primary refractive overcorrection.

METHODS

Prospective case series enrolled 14 pseudophakic eyes of 14 patients, 5-9 years old, with history of cataract surgery and primary in the bag-intraocular lenses (IOL) implantation, followed by myopic shift and/or refractive overcorrection and anisometropic amblyopia of variable degrees. All cases had implantation of a piggyback ICL/toric ICL, to correct the myopia/myopic astigmatism. Preoperatively, we evaluated the uncorrected distance visual acuity (UCVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), intraocular pressure (IOP) and endothelial cell density (ECD). We assessed the position and vaulting of the ICLs on slit lamp examination and confirmed by Scheimpflug tomography. Postoperative follow-up was at 1st week and 1, 3, 6, 9, 12, 18 and 24 months.

RESULTS

Uncorrected distance visual acuity improved in all cases, and CDVA improved in 11 amblyopic eyes (2-4 lines). There was no evidence of interlenticular opacification (ILO) throughout the 2-year follow-up. Two cases were complicated with early postoperative acute elevation of IOP and were controlled with topical beta-blockers. Postoperative acute anterior uveitis occurred in six eyes and controlled by topical steroids. Implantable collamer lens (ICL) vault was measured using Pentacam, with mean value of 470 ± 238 μm.

CONCLUSION

Sulcus implantation of the secondary piggyback ICL to correct unilateral pseudophakic myopic refractive error in children was safe, efficient, predictable and well tolerated in management of anisometropic amblyopia in all eyes.

Acute hydrops with secondary bacterial keratitis: sequelae of paediatric refractive surgery

A 24-year-old male patient with bilateral high myopia presented to our outpatient department with sudden onset of pain and diminution of vision in his right eye. He had sequentially undergone bilateral trabeculectomy and photorefractive keratectomy at the age of 6 years in both eyes. This was followed by radial keratotomy in right eye at the age of 8 years. The slit lamp examination demonstrated the presence of infiltrates in central cornea with an underlying fluid cleft, along with 14 radial keratotomy scars. Anterior segment optical coherence tomography confirmed the presence of intrastromal cleft in communication with anterior chamber. Bacterial culture revealed coagulase-negative Staphylococcus. The patient was successfully treated with fortified antibiotics in conjunction with the sensitivity report. This case underlines the need for a cautious approach towards refractive surgery in paediatric age group and highlights the long-term sequelae of retreatments in these cases.

Posterior sclera reinforcement and phakic intraocular lens implantation for highly myopic amblyopia in children: a 3-year follow-up

PURPOSE

To study the safety and efficacy of posterior scleral reinforcement (PSR) combined with phakic intraocular lens (PIOLs) implantation for highly myopic amblyopia in children.

METHODS

This study included eight highly myopic children (11 eyes) who failed in conventional therapy for amblyopia using various combination of spectacles, contact lenses, and intensive patching before enrollment into this study. They were treated sequentially with PSR and PIOL implantation, and were followed up for 3 years after surgery. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) in LogMAR, spherical equivalent power (SE), and complications were evaluated.

RESULTS

Before surgery, the mean UCVA was 1.59±0.33, BCVA, 0.74±0.37, SE, -17.57±5.56D, the axial length (AL), 30.09±2.18 mm. After PSR, BCVA improved one line in three patients, the rest were unchanged, and AL was unchanged among all cases. Six eyes of three patients were implanted with an iris-claw PIOL and five eyes of five patients were implanted with a posterior PIOL. After completion of treatment, the mean UCVA was 0.44±0.21, BCVA 0.38±0.24, SE -0.54±0.74 D, and AL 30.35±2.29 mm. No patient experienced complications.

CONCLUSION

Combined PSR and PIOL implantation treatment for highly myopic amblyopia in children is safe and effective.

Severe anisometropic myopia in identical twins

High anisometropic myopia is a rare condition in twins. Genetic factors have been implicated in its development and there may be an association with vision-threatening complications. A pair of 11-year-old twins presented with poor distance vision in both eyes. Detailed ocular examination was performed including slit lamp examination, dilated funduscopy, cycloplegic refraction, keratometry and axial length measurement. The objective refraction was -6.50DS -2.00DC × 180 (right eye), -1.00DS (left eye) for the first twin; -13.75DS -2.25DC × 180 (right eye), -0.50DS -0.75DC × 04 (left eye) for the second twin. This case suggests an underlying genetic defect in the development of myopia.

Myopic regression after phakic intraocular lens implantation and LASIK

PURPOSE

In myopia, biometry including the axial length is important, along with the refractive data. We compared the rates of myopic regression 3 years after phakic intraocular lens (pIOL) implantation and laser in situ keratomileusis (LASIK) after matching the preoperative axial length in highly myopic eyes of Japanese patients.

METHODS

This retrospective nonrandomized study included 133 eyes of 84 patients with myopia exceeding -6.00 diopters (D) who underwent implantation of two iris-fixated pIOLs (pIOL group, 66 eyes/46 patients) or myopic LASIK (LASIK group, 67 eyes/38 patients) who were followed for more than 3 years postoperatively. The patient age, preoperative refraction, and preoperative axial length were matched between the study groups.

RESULTS

There were no significant differences preoperatively between the groups in age, intraocular pressure, refraction, keratometry, or axial length. The mean regression values after 3 years compared with the 1-month postoperative refractions were -0.12 ± 0.47 (SD) D in the pIOL group and -0.82 ± 0.69 D in the LASIK group (p < 0.001). The differences in the mean regression rates between 1 and 12 months, 12 and 24 months, and 24 and 36 months of follow-up were, respectively, 0.09 ± 0.38 D, -0.11 ± 0.35 D, and -0.11 ± 0.30 D in the pIOL group and -0.57 ± 0.84 D, -0.24 ± 0.47 D, and 0.00 ± 0.53 D in the LASIK group (p < 0.001, p = 0.07, p = 0.15, respectively).

CONCLUSIONS

There was a significant difference in myopic regression 3 years postoperatively between the groups matched for preoperative axial length in Japanese patients. This result has the potential to elucidate myopia in the future.

Myopia onset and progression: can it be prevented?

Myopia is the commonest ocular abnormality and the high and growing prevalence of myopia, especially but not only in Asian populations, as well as its progressive nature in children, has contributed to a recent surge in interest. Such worldwide growing prevalence seems to be associated with increasing educational pressures, combined with life-style changes, which have reduced the time that children spend outdoors. Highly nearsighted people are at greater risk for several vision-threatening problems such as retinal detachments, choroidal neovascularization, cataracts and glaucoma, thus the potential benefits of interventions that can limit or prevent myopia progression would be of remarkable social impact. Our understanding of the regulatory processes that lead an eye to refractive errors is undoubtedly incomplete but has grown enormously in the last decades thanks to the animal studies, observational clinical studies, and randomized clinical trials recently published. In this review we assess the effects of several types of life-style and interventions, including outdoor activities, eye drops, undercorrection of myopia, multifocal spectacles, contact lenses, and refractive surgery on the onset and progression of nearsightedness.

Ocular aberrations in amblyopic children

PURPOSE

To study the pattern of ocular aberrations in amblyopic children, and evaluate a possible relation to etiology and treatment outcomes of amblyopia.

METHODS

The WaveScan Wavefront System (AMO, Santa Ana, CA, USA) aberrometer was used to assess 75 eyes (60 children) after instillation of 1% cyclopentolate eyedrops. There were 29 males and 31 females with a mean age of 9.23 ± 2.55 years (range, 5-14 years). The study sample was subdivided into four groups; 16 emmetropic non-amblyopic eyes (control group); 24 pre-treatment newly diagnosed amblyopic eyes; 16 eyes of treated amblyopes and; 19 eyes with refractory amblyopia.

RESULTS

Amblyopes had statistically significant greater root mean square (RMS) values for whole eye aberrations, 2nd order aberrations, defocus ([Formula: see text]) and astigmatism ([Formula: see text]) compared to emmetropes (P < 0.0001). The refractory amblyopic group showed statistically significant differences in whole eye RMS, 2nd order- aberrations, defocus ([Formula: see text]) and astigmatism ([Formula: see text]) when compared to treated amblyopic groups (P < 0.0001). Apart from a statistically significant difference in 5th order RMS of pre-treated amblyopes versus the control group, no other significant differences were found in higher order aberrations (HOAs: coma, spherical, higher-order astigmatism, trefoil, or 3rd, 4th, 5th or 6th order terms) between emmetropes and any of the amblyopic groups.

CONCLUSION

Lower order aberrations remain the major factor that affect retinal image quality and hence amblyopia development especially in ametropic eyes. This can be corrected optically. Studying HOA profile in amblyopic eyes failed to explain why refractory amblyopia does not respond to orthoptic treatments. This outcome indicates that theories of central problems in image processing and binocular interaction are likely the main cause of refractory amblyopia.

The influence of compliance with the use of refractive correction in hyperopic children on accommodation

PURPOSE

To indicate the relationship between constant, correct use of hyperopic spectacles and relaxation of accommodation in children.

METHODS

After thorough ophthalmic examination (cycloplegia included), 52 children 2.5 to 9 years old were detected with hyperopia >3 D, out of all examined within a year. These children were fully or partially corrected, with hyperopic glasses, depending on whether accommodative esotropia was or was not present. Constant and correct use of spectacles was strongly suggested to all children. During follow-up 3 and 6 months later, the amount of manifest hyperopia was measured in each case by an autorefractometer (without the use of cycloplegic factor).

RESULTS

Out of the 52 children, 37 who participated in our study fully complied with hyperopic spectacle treatment, wearing their glasses constantly and correctly. The 15 others wore their glasses partially or not at all or made incorrect use of them. During follow-up 3 and 6 months later, refractive measurements of manifest hyperopia in the first group of children were identical or similar to the refractive power of their glasses. On the contrary, in the second group of children, strong accommodation did not allow the expression of hyperopia, and in a few cases myopic refractive measurements appeared (similar to those on the first examination, before spectacle treatment was prescribed).

CONCLUSIONS

Constant and correct use of hyperopic spectacles leads to relaxation of accommodation in children and is thus an accurate indicator of compliance.

Posterior chamber toric phakic IOL implantation for the management of pediatric anisometropic amblyopia

PURPOSE

To report the outcomes of toric posterior chamber phakic intraocular lens (PIOL) implantation in children for the treatment of amblyopia due to anisometropia with astigmatism.

METHODS

Six eyes of 6 amblyopic patients aged 5 to 15 years underwent toric PIOL (Visian Toric ICL; STAAR Surgical Company, Monrovia, CA) implantation for refractory anisometropic amblyopia. Preoperative and postoperative clinical evaluation included slit-lamp microscopy, visual acuity, anterior/posterior segment examination, and cycloplegic refraction.

RESULTS

After a mean follow-up of 23 months (range: 15 to 34 months), mean spherical equivalent cycloplegic refraction improved from -10.21 ± 4.62 diopters (D) (range -7.5 to -19.5 D) preoperatively to -0.42 ± 0.39 D (range: -0.625 to +0.125 D) postoperatively. Corrected distance visual acuity ranged from 20/40 to 20/200 preoperatively and 20/20 to 20/60 postoperatively. Five of the 6 eyes gained more than 3 lines of corrected distance visual acuity with a maximum gain of 8 lines in one eye. One eye showed an improvement of more than 2 lines (change in preoperative visual acuity of 20/100 to 20/60 postoperatively). No patients lost any lines of visual acuity. All eyes remained quiet. All PIOLs remained well centered throughout the follow-up period.

CONCLUSION

Toric PIOL implantation may be a viable therapeutic modality in children with clinically significant anisometropic ametropia and astigmatism with secondary amblyopia who have been refractory to medical treatment including spectacles or contact lenses. Longer follow-up visits with larger sample populations will evaluate more effectively the long-term efficacy and late-onset of complications.

Intraobserver reliability of contact pachymetry in children

BACKGROUND

Central corneal thickness (CCT) is an important measurement in the treatment and management of pediatric glaucoma and potentially of refractive error, but data regarding reliability of CCT measurement in children are limited. The purpose of this study was to evaluate the reliability of CCT measurement with the use of handheld contact pachymetry in children.

METHODS

We conducted a multicenter intraobserver test-retest reliability study of more than 3,400 healthy eyes in children aged from newborn to 17 years by using a handheld contact pachymeter (Pachmate DGH55; DGH Technology Inc, Exton, PA) in 2 clinical settings--with the use of topical anesthesia in the office and with the patient under general anesthesia in a surgical facility.

RESULTS

The overall standard error of measurement, including only measurements with standard deviation ≤5 μm, was 8 μm; the corresponding coefficient of repeatability, or limits within which 95% of test-retest differences fell, was ±22.3 μm. However, standard error of measurement increased as CCT increased, from 6.8 μm for CCT less than 525 μm, to 12.9 μm for CCT 625 μm and greater. The standard error of measurement including measurements with standard deviation >5 μm was 10.5 μm. Age, sex, race/ethnicity group, and examination setting did not influence the magnitude of test-retest differences.

CONCLUSIONS

CCT measurement reliability in children via the Pachmate DGH55 handheld contact pachymeter is similar to that reported for adults. Because thicker CCT measurements are less reliable than thinner measurements, a second measure may be helpful when the first exceeds 575 μm. Reliability is also improved by disregarding measurements with instrument-reported standard deviations >5 μm.

Refractive surgery for accommodative esotropia: past, present, and future

INTRODUCTION

Refractive surgery has the potential to be a definitive treatment for accommodative esotropia, yet it has not been widely embraced. This article reviews the current literature on refractive surgery to treat accommodative esotropia.

METHODS

A literature search was performed using the following terms: refractive surgery, photorefractive keratectomy, laser-assisted keratomileusis, intraocular lens, hyperopia, accommodative esotropia, children, pediatric.

RESULTS

Fifteen series of patients treated with refractive surgery for accommodative esotropia were identified and summarized.

CONCLUSIONS

Refractive surgery holds promise for the treatment of accommodative esotropia, although treatment risks are present and additional investigation is needed.

Visual acuity after laser in situ keratomileusis to correct high astigmatism in adults with meridional amblyopia

PURPOSE

To analyze the effect of laser in situ keratomileusis to correct high myopic astigmatism in patients with suboptimal best spectacle-corrected visual acuity (BSCVA).

DESIGN

Retrospective, interventional series of consecutive cases.

METHODS

SETTING

Vissum Madrid, Madrid, Spain.

PATIENTS

Two hundred five eyes of consecutive patients with suboptimal BSCVA and high myopic astigmatism of -3 diopters or more.

INTERVENTION

Laser in situ keratomileusis surgery.

MAIN OUTCOME MEASURES

BSCVA.

RESULTS

The BSCVA (decimal Snellen fraction notation) improved significantly (P = .0001) from a mean preoperative 0.77 ± 0.18 (range, 0.05 to 0.90) to 0.81 ± 0.19 (range, 0.05 to 1.25) 3 months after surgery. The mean change in lines of BSCVA (decimal Snellen fraction notation) was 0.04 ± 0.11 (range, -0.25 to 0.4). A significant inverse relationship (P = .001) was found between the preoperative BSCVA and the improvement in BSCVA.

CONCLUSIONS

In eyes with high myopic astigmatism and suboptimal preoperative BSCVA, laser in situ keratomileusis may result in a significant improvement in BSCVA.

Photorefractive keratectomy in treatment of refractive amblyopia in the adult population

PURPOSE

To evaluate changes in corrected distance visual acuity (CDVA) after photorefractive keratectomy (PRK) in amblyopic cases.

SETTING

Ankara Ataturk Training and Research Hospital 1st Ophthalmology Clinic, Ankara, Turkey.

DESIGN

Retrospective case series.

METHODS

The medical records of cases of anisometropic amblyopia treated by excimer laser PRK were reviewed. Inclusion criteria were no previous refractive correction, occlusion treatment, or chemical penalization before age 15 years. Anisometropic amblyopia was defined as a more than 2-line difference in CDVA and a refractive error difference greater than 3.00 diopters (D) between 2 eyes of the same patient. Final visual acuity measurements were performed at the end of the sixth postoperative month.

RESULTS

The study enrolled 16 hyperopic patients and 34 myopic patients with a mean age of 33.3 years. The mean preoperative spherical equivalent was -7.46 D ± 2.90 (SD) in myopic eyes and +4.15 ± 2.56 D in hyperopic eyes. The differences between the preoperative and postoperative uncorrected distance visual acuity and CDVA were statistically significant (P=.001). The mean CDVA was 0.47 ± 0.17 preoperatively and 0.61 ± 0.19 postoperatively. The CDVA decreased in 3 cases (6%), stayed the same in 12 cases (24%), and increased in 35 cases (70%). There was no statistically significant correlation between the severity of amblyopia and the increase in CDVA (r = 0.20, P=.165).

CONCLUSION

After PRK to eliminate and correct refractive errors in anisometropic amblyopia, visual acuity improved significantly in 70% of adult patients with no previous occlusion or chemical penalization treatment.

Pediatric phakic intraocular lens surgery: review of clinical studies

PURPOSE OF REVIEW

To report on the accumulating peer-reviewed data of phakic intraocular lens (pIOL) implantation in the pediatric population. I evaluate and compare the published peer-reviewed articles for the reported efficacy and complications of phakic intraocular lens implantations in children for correction of clinically significant high refractive errors.

RECENT FINDINGS

Multiple studies have shown the relevancy and effectiveness of pIOL implantation as an alternative surgical management for highly significant pediatric ametropia in selective patients who are noncompliant with medical treatment.

SUMMARY

In the management of clinically significant severe pediatric ametropic and/or anisometropic myopia or hyperopia and in the event of nonadherence to traditional medical treatment, phakic anterior chamber IOL implantation is currently considered an effective modality of treatment. Long-term follow-up of pediatric patients following pIOL implantation is necessary. Future clinical trials should focus on children of various age groups to assess the variables of visual acuity gain or loss, stereopsis, contrast sensitivity, high-order aberrations, corneal physiology, and long-term complications to accurately and properly address the safety and efficacy of the type of and the best time for pIOL implantation in treatment and/or prevention of amblyopia in children.

Refractive lens exchange with intraocular lens implantation in hyperopic eyes of a patient with Angelman syndrome

We describe a patient with Angelman syndrome with severe developmental delay who was visually impaired by uncorrected high hyperopia and poor control of accommodation. Refractive lens exchange with intraocular lens implantation was performed in both eyes when the patient was 22 years of age. Satisfactory anatomical and functional outcomes were achieved and maintained during 3 years of follow-up. Refractive lens exchange can be useful in patients with severe neurobehavioral disorders in the presence of high refractive error and poor accommodative control.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Refractive surgery in children

PURPOSE OF REVIEW

To evaluate recent literature regarding indications and outcomes for refractive surgery in children, including laser in-situ keratomileusis, laser epithelial keratomileusis, photorefractive keratectomy, and refractive intraocular lens placement.

RECENT FINDINGS

Refractive surgery in children is controversial. Recent publications have reported refractive surgery to treat strabismus and both ametropic and anisometropic amblyopia. Questions remain as to the age at which to perform the surgery, and which specific procedure to perform. Choice of technique depends on the clinical situation.

SUMMARY

Refractive surgery is an option for children with amblyopia and strabismus who fail treatment with spectacles or contact lenses. Prospective controlled studies are needed, and longer follow-up will answer questions about the utility and safety of refractive surgery in children.