Laser-assisted subepithelial keratectomy and photorefractive keratectomy versus conventional treatment of myopic anisometropic amblyopia in children

Pediatric refractive surgery: Review article

Refractive surgery is one of the most commonly performed elective procedures in ophthalmology; it is mostly performed in patients who are older than 18 years of age. This routine procedure has been time-tested and is proven to be both safe and effective in adults. However, little is known about the safety and efficacy of refractive surgery in pediatric patients. Granted, refractive surgery should not be used in kids merely for the purpose of avoiding spectacles wear, but it can be of valuable help is preserving vision in patients with amblyopia and accommodative esotropia who otherwise couldn't comply with traditional management options. Refractive surgery in pediatric patients is a complex and challenging field due to the unique characteristics of their developing eyes. This review article aims to provide an overview of the current literature on refractive surgery in pediatric patients, focusing on the different surgical options, the advantages and disadvantages of each procedure.

The Relationship Between Binocular Imbalance and Myopic Shift in Unoperated Eyes After Unilateral SMILE and tPRK

Purpose

The purpose of this study was to investigate the relationship between binocular imbalance and myopic shift in unoperated eyes after unilateral small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK) procedures.

Methods

This study included 51 participants who had undergone unilateral SMILE (n = 28) or tPRK (n = 23) for at least 3 months. The participants were categorized into stable and myopic shift groups based on the difference between preoperative and postoperative spherical equivalent refractive (SER) errors of unoperated eyes. Psychophysical tests were conducted only at the postoperative follow-up point. Spatial sensory eye dominance was determined by analyzing a binocular orientation combination task at spatial frequencies of 1 and 6 cycles per degree (c/d). A rotating cylinder generated a spontaneous Pulfrich phenomenon to determine the interocular delay at spatial frequencies of 0.95 and 2.95 c/d.

Results

The logrBP in the myopic shift group was significantly more negative than in the stable group at 1 c/d (P < 0.01) and 6 c/d (P < 0.01). And logrBP correlated with the difference between preoperative and postoperative SER of the unoperated eye at 1 c/d (rs = 0.513, P < 0.001) and 6 c/d (rs = 0.504, P < 0.001). In the myopic shift group, logrBP was more negative at 6 c/d than at 1 c/d (P = 0.013), but not in the stable group.

Conclusions

Patients who experience myopic shift in the unoperated eye after unilateral SMILE or tPRK tend to have stronger sensory eye dominance in that eye, with a more pronounced dominance at higher spatial frequencies.

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.

Techniques in pediatric refractive surgery

Pediatric refractive surgery treats refractive errors and their associated comorbidities such as amblyopia and strabismus in special needs children intolerant of spectacles or contact lenses. Children with neurobehavioral disorders undergoing refractive surgery have improvements in visual acuity, communication, socialization, motor skills, adaptive behaviors, visual perception, and cognitive function. Contrary to adults, amblyopia is frequently an indication for refractive surgery in special needs children. Pediatric refractive surgery techniques modify ametropia at the corneal, anterior chamber, posterior chamber, and lens planes. This article will discuss the most common modalities used today in pediatric refractive surgery, including laser keratorefractive surgery, phakic intraocular lenses, and refractive lens exchange. Practical pearls are discussed for the implementation of pediatric refractive surgery, reviewing preoperative diagnostics, surgical techniques, and postoperative care.

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.

A clinical trial on phakic intraocular lens for the treatment of refractive amblyopia in children and adolescents

PURPOSE

To analyze the demographics and clinical outcomes of posterior chamber phakic intraocular (IOL) implantation for refractive amblyopia in children and adolescents.

METHODS

A prospective interventional study was performed on children and adolescents with amblyopia at a tertiary eye care center from January 2021 to August 2022. Twenty-three eyes of 21 anisomyopic and isomyopic amblyopia patients operated for posterior chamber phakic IOL (Eyecryl phakic IOL) as a treatment for amblyopia were included in the study. Patient demographics, pre- and postoperative visual acuity, cycloplegic refraction, anterior and posterior segment examination, intraocular pressure, pachymetry, contrast sensitivity, endothelial count, and patient satisfaction scores were evaluated. Patients were followed up at day 1, 6 weeks, 3 months, and 1 year after surgery, and visual outcomes and complications were documented.

RESULTS

The mean age of patients was 14.16 ± 3.49 years (range: 10-19 years). The mean intraocular lens power was - 12.20 diopter spherical (DS) in 23 eyes and - 2.25 diopter cylindrical (DC) in four patients. The mean unaided distant visual acuity (UDVA) and best-corrected visual acuity (BCVA) were 1.39 ± 0.25 and 0.40 ± 0.21 preoperatively on the log of minimum angle of resolution (logMAR) chart. Postoperatively, the visual acuity improved by 2.6 lines in 3 months period and maintained till 1 year. Postsurgery, contrast sensitivity in the amblyopic eyes significantly improved, and the average endothelial loss recorded was 5.78% at 1 year, which was statistically insignificant. Patient satisfaction score was statistically significant, with 4.736/5 recorded on the Likert scale.

CONCLUSION

Posterior chamber phakic IOL is a safe, effective, and alternative method for treating amblyopia patients who are noncompliant with glasses, contact lenses, and keratorefractive procedures.

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.

[TransPRK in general anesthesia-An alternative for anxious patients]

OBJECTIVE

The aim was to analyze and compare the refractive results of anxious patients treated with transepithelial photorefractive keratectomy (TransPRK) while under general anesthesia (ITN) versus patients treated under local anesthesia (TRO).

MATERIAL AND METHODS

The TransPRK treatment was performed with the AMARIS 1050 RS laser (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany) in a group of patients with ITN and a group of patients, treated as usual with TRO. The method used an aspheric aberration neutral ablation profile, as well as SmartPulse technology and 7D eyetracking. In ITN propofol and rocuronium were injected intravenously. The artificial respiration was via a resuscitation bag after intubation with a laryngeal mask. To achieve pain insensitivity in the group of patients in TRO three drops of Conjucain Edo 0.4% were instilled at intervals of a few minutes. Follow-up examinations were performed after 1 and 4 days and after 1 and 3 months.

RESULTS

A total of 35 consecutive TransPRK laser treatments under ITN were retrospectively compared with a group of 699 eyes treated with TransPRK under TRO in the period from February 2017 to December 2021. The preoperative sphere had a range of -5.50 to -1.0 dpt, the average cylinder was 1.19 dpt and cylinders were treated up to 4.75 dpt. The results after 3 months follow-up showed a predictability of 100% eyes within the target correction of less than 0.5 dpt in ITN and in TRO 97%. The astigmatic correction showed 91% of eyes in ITN with less than 0.5 dpt and an angle of error of 83% within ±5°. In TRO 96% of eyes showed astigmatic correction with less than 0.5 dpt and an angle of error of 77% within ±5°. After 3 months 83% of eyes treated in ITN reached a visual acuity of 1.0 or more and 84% of eyes treated in TRO.

CONCLUSION

The TransPRK performed in ITN led to equal refractive results than when treated as usual in TRO. For anxious patients there is the possibility of laser vision correction in ITN. Because of shorter treatment time and accordingly shorter time under general anesthesia, TransPRK is an advantage for LASIK surgery.

Ten-Year Outcomes of LASIK for Pediatric Myopic Anisometropia

Purpose

To evaluate long-term safety, effectiveness, and stability of unilateral LASIK in pediatric myopic anisometropic amblyopia.

Methods

This retrospective study included children who received unilateral LASIK for myopic anisometropia of >6 D, after mandatory 6-month occlusion/penalization therapy. They were evaluated at 6 months, 1 year, 2 years and biannually until 10 years. Outcome measures included visual acuity, refraction, ocular alignment, stereopsis, corneal clarity, and corneal topography.

Results

32 patients (16 girls) with mean age of 8.6 ± 2.3 years completed 10 years of follow up after unilateral LASIK. Mean preoperative spherical equivalent refraction (SER) was -10.3D ±2.0D in the affected eye, with anisometropic difference of -9.5D ±1.7D. Mean post-LASIK SER was -1.3D±0.8D (p<0.001). Anisometropia significantly decreased to 0.3D±0.8D, 0.4D±1.0D, and 1.0±2.5D at 6 months, 1 year and 10 years respectively (p<0.001). 11 patients (34%) who had preoperative intermittent exotropia (< 15°) regained orthophoria in all gazes, while 5 of 10 who had constant exotropia with large angle (>30°) required strabismus surgery for ocular alignment. BCVA improved from 0.04±0.6 Decimal at baseline to 0.6 ±0.2 after LASIK and occlusion therapy (p< 0.001). Despite insignificant refractive regression in both eyes, patients have maintained orthophoria, improved stereopsis, clear cornea, and the topography showed no evidence of post-LASIK ectasia.

Conclusion

LASIK appears safe, effective, and stable for correcting refractory pediatric myopic anisometropia, in which conventional measures fail or endanger normal visual development. Eliminating anisometropic aniseikonia consequently restores binocular vision and stereopsis which, along with amblyopia therapy, would reverse amblyopia and prevent recurrence.

Effectiveness of Laser Refractive Surgery to Address Anisometropic Amblyogenic Refractive Error in Children: A Report by the American Academy of Ophthalmology

PURPOSE

To review the published literature assessing the safety and effectiveness of laser refractive surgery to treat anisometropic amblyogenic refractive error in children aged ≤ 18 years.

METHODS

A literature search of the PubMed database was conducted in October 2021 with no date limitations and restricted to publications in English. The search yielded 137 articles, 69 of which were reviewed in full text. Eleven articles met the criteria for inclusion and were assigned a level of evidence rating.

RESULTS

The 11 included articles were all level III evidence and consisted of 1 case-control study and 10 case series. Six studies used laser-assisted in situ keratomileusis (LASIK), 1 used photorefractive keratectomy (PRK), 1 used refractive lenticule extraction/small incision lenticule extraction, and the rest used a combination of LASIK, PRK, laser epithelial keratomileusis (LASEK), or refractive lenticule extraction/small incision lenticule extraction. Five studies enrolled patients with anisometropic myopia, 2 studies enrolled patients with anisometropic hyperopia, and the remainder were mixed. Although all studies demonstrated an improvement in best-corrected visual acuity (BCVA), the magnitude of improvement varied widely. As study parameters varied, a successful outcome was defined as residual refractive error of 1 diopter (D) or less of the target refraction because this was the most commonly used metric. Successful outcomes ranged between 38% and 87%, with a mean follow-up ranging from 4 months to 7 years. Despite this wide range, all studies demonstrated an improvement in the magnitude of anisometropia. Regression in refractive error occurred more frequently and to a greater degree in myopic eyes and eyes with longer follow-up, and in younger patients. Although one study reported 2 free flaps, most studies reported no serious adverse events. The most common complications were corneal haze and striae.

CONCLUSIONS

Findings from included studies suggest that laser refractive surgery may address amblyogenic refractive error in children and that it appears to decrease anisometropia. However, the evidence for improvement in amblyopia is unclear and long-term safety data are lacking. Long-term data and well-designed clinical studies that use newer refractive technologies in standardized patient populations would help address the role of refractive surgery in children and its potential impact on amblyopia.

The Study of Short-Term Plastic Visual Perceptual Training Based on Virtual and Augmented Reality Technology in Amblyopia

Backgrounds. The treatment for amblyopia can have a substantial impact on quality of life. Conventional treatments for amblyopia have some limitations, then we try to explore a new and effective method to treat amblyopia. This study aimed to determine the potential effect of short-term plastic visual perceptual training based on VR and AR platforms in amblyopic patients. Methods. All observers were blinded to patient groupings. A total of 145 amblyopic children were randomly assigned into 2 groups: VR group (71 patients) and AR group (74 patients). In the VR group, each subject underwent a 20-min short-term plastic visual perceptual training based on a VR platform, and in the AR group, based on an AR platform. The best-corrected visual acuity (BCVA), fine stereopsis, and contrast sensitivity function (CSF) were measured before and after training. Results. The BCVA (P < 0.001) and fine stereopsis (P < 0.05) were improved significantly both in VR and AR group after training. Moreover, in the AR group, the CSF showed the value of all spatial frequencies had a statistically significant improvement after training (P < 0.05), while in the VR group, only the value of spatial frequency 12 improved significantly (P = 0.008). Conclusions. This study showed that the short-term plastic visual perceptual training based on VR and AR technology can improve BCVA, fine stereopsis and CSF of refractive amblyopia. It was suggested that the visual perceptual training based on the VR and AR platforms may be potentially applied in treatment for amblyopia and provided a high-immersing alternative.

Corneal morphological changes after small incision lenticule extraction for myopic anisometropia

Purpose

This research aims to study the corneal morphological changes in adult patients with myopic anisometropia after small incision lenticule extraction (SMILE) and the safety, efficacy, and predictability of clinical outcomes.

Methods

This was a prospective cohort study. Patients with myopic anisometropia [refractive difference &gt;2.0 diopters (D)] were included in this study who underwent SMILE at our hospital from September 2019 to March 2021. For the two eyes of each patient, the one with higher myopia was defined as group A, and the fellow eye was group B. The follow-up time points were set as 1 week, 1 month, 3 months, and 6 months after the surgery. The data collected were uncorrected and best-corrected distance visual acuity (UDVA and CDVA), spherical equivalent (SE), efficacy and safety indexes, posterior corneal elevation (PCE), anterior and posterior corneal radius of curvature in the 3 mm area at the center of the thinnest point of the cornea (ARC and PRC), and higher-order aberrations (HOAs).

Results

The study included 36 patients (72 eyes), and the mean age was 25.2 ± 6.4 years. The preoperative SEs were −6.45 ± 1.25 D in group A and −3.76 ± 1.29 D in group B. Six months after surgery, the SEs in groups A and B were −0.09 ± 0.50 D and 0.07 ± 0.47 (P = 0.059), respectively. The efficacy indexes were 1.06 ± 0.16 in group A and 1.07 ± 0.14 in group B (P = 0.750). The safety indexes were 1.08 ± 0.14 in group A and 1.12 ± 0.15 in group B (P = 0.173). The PCE was significantly reduced at 6 months after surgery in pagebreak both groups (P &lt; 0.05). The ARC was significantly higher than before the surgery (P &lt; 0.05) in the two groups. The two groups showed significant increases in total HOAs, coma 90°, and spherical aberrations (P &lt; 0.05).

Conclusion

SMILE is predictable, effective, and safe in correcting myopic anisometropia. The postoperative changes in HOAs are characteristic.

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.

Developmental Improvement in Children With Intellectual Disability After Photorefractive Keratectomy for Severe Isoametropia

PURPOSE

To assess the impact of refractive error correction from photorefractive keratectomy on development in children with severe isoametropia, subnormal visual acuity, and intellectual disability unable to use refraction correction.

DESIGN

Prospective noncomparative interventional case series.

METHODS

Before and after photorefractive keratometry (PRK), subjects who had plateaued developmentally for 18 or more months were assessed using a battery of developmental tests. The primary outcome measure was the change in the developmental quotient (DQ) 6 months after PRK. Secondary outcomes were the change in the DQ, uncorrected visual acuity, cycloplegic refraction, and corneal status 12, 24, and 36 months after PRK.

RESULTS

Sixteen subjects aged 2 to 8 years were included. Twelve were highly myopic (mean, -9.69 ± 3.82 diopters [D]), 3 highly hyperopic (mean, +5.75 ± 0.59 D) and 1 highly astigmatic (mean, +3.50 D). Six months after PRK, the DQ significantly improved for expressive communication (mean, 4.51 ± 2.27 months; P = .04), interpersonal relationships (mean, 9.45 ± 4.18 months; P = .02) and coping (mean, 6.44 ± 2.10 months; P = .05). Twelve months after PRK, the DQ significantly improved for receptive communication (8.04 ± 1.80 months; P < .001), expressive communication (6.99 ± 2.27 months; P < .05), written communication (9.28 ± 3.72 months; P < .04), domestic skills (6.50 ± 2.43 months; P < .03), interpersonal relationships (10.57 ± 4.17 months; P < .02), and coping (8.41 ± 3.25 months; P < .5).

CONCLUSIONS

PRK significantly improves developmental abilities of children with intellectual disability, severe isoametropia, and previously plateaued development, in addition to improving visual acuity and refractive error.

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.

Visual acuity, refractive error, and regression outcomes in 169 children with high myopia who were implanted with Ophtec-Artisan or Visian phakic IOLs

PURPOSE

To analyze outcomes in a large cohort of spectacle-aversive children with high myopia who were treated by implantation of the Ophtec-Artisan or Visian phakic intraocular lens (pIOL).

METHODS

Outcome data were collated retrospectively in 78 children (115 eyes) implanted with the Ophtec-Artisan iris-enclaved anterior chamber pIOL and 91 children (154 eyes) implanted with the Visian ICL (intraocular collamer lens) sulcus pIOL. All children had difficulties with spectacle or contact lens wear. Mean age at surgery was 9.9 years; mean follow-up was 3.9 years (range, 0.6-14.1 years).

RESULTS

A total of 248 of 269 eyes (92%) were corrected to within ± 0.5 D of their target value. Spherical correction averaged 12.3 ± 1.0 D. Refractive spherical regression was -0.04 D/year at last follow-up. Uncorrected distance visual acuity improved from an average logMAR 1.8 to 0.4; corrected distance visual acuity improved an average 0.3 logMAR. Of the treated children, 68% had a gain in binocular fusion. Neurobehavioral and/or visuomotor comorbidities were present in 87% of children. Five eyes (2%) developed retinal detachment an average 6 years after implantation. Nine eyes (3%) implanted with the Ophtec-Artisan pIOL required repositioning after trauma.

CONCLUSIONS

Implantation of pIOLs in children is an effective method for correcting high myopia in spectacle noncompliant children. Rates of myopic regression after pIOL surgery are substantially lower than those reported for children treated by excimer laser photorefractive keratectomy (PRK). The prevalence of major complications was relatively low in this high-risk population.

The relationship between clinical measures of aniseikonia and stereoacuity before and after LASIK

PURPOSE

To determine the significance of changes and and inter-relationships between three markers of binocular function (aniseikonia, distance and near stereoacuity) following unremarkable LASIK at 3 and 6 months postoperatively.

METHODS

All patients underwent LASIK using the Schwind Amaris 750S and the flaps were created using Intralase 150 kHz. Patients were I, monocular myopes II, binocular myopes III, binocular hyperopes IV, binocular astigmats V, anisometropes and VI, matched age and gender control (n = 20 in each group except III where n = 18). Aniseikonia (Awaya test), distance and near stereoacuity (Randot tests) were measured before surgery, and at 3 and 6 months after surgery. At all times data were collected under constant conditions and analyzed using appropriate non-parametric statistical tests.

RESULTS

The following statistically significant changes were found after applying the Bonferroni correction (p ≤ 0.001); aniseikonia reduced (groups I, III, IV, V), stereoacuity improved at distance (groups I, III-V) and near (groups I, V). Inter-group differences in aniseikonia distance and near stereoacuity were significant preoperatively, but not postoperatively. In groups I, IV and V, the changes in aniseikonia and stereoacuity (near and distance) were significantly correlated with the preoperative value. Aniseikonia was significantly correlated with distance and near stereoacuity preoperatively but not postoperatively.

CONCLUSION

Binocular function improved in all groups after LASIK except in binocular myopes. In general, binocular function was still low compared with the control group at six months postoperatively. It is unclear why binocular function improved in the binocular astigmats.

Threshold Values of Myopic Anisometropia Causing Loss of Stereopsis

Purpose

The aim of the study was to determine the threshold values of myopic anisometropia that lead to the loss of stereoacuity in most of patients.

Materials and Methods

Forty healthy subjects were included in the study. The inclusion criteria were as follows: lack of any functional or morphological ophthalmological disorders, or detectable damage to the visual system, anisometropia equal or less than 0.25 D in a spherical equivalent, and full stereoscopic vision for near and for distance. Myopic anisometropia was evoked by placing different focusing lenses in front of the right eye of the subject in the trial frame. Stereoscopic vision was assessed with the use of the Titmus test (dots) (Stereo Fly Test Stereo Optical Co. Inc.) for near and the Randot test for distance (Distance Randot Stereotest Stereo Optical Co. Inc.).

Results

The threshold values for different types of myopic anisometropia for the loss of stereopsis in more than 50% of patients were determined. For near, this value was 3 D for sphere and “against the rule astigmatism” and 4 D for “with the rule astigmatism”. For distance, the values were 2 D for sphere and “against the rule astigmatism” and 3 D for “with the rule astigmatism.” Conclusions. Myopic anisometropia of more than 2 D can cause a significant impairment of binocular vision. Stereoacuity at distance is more sensitive to myopic anisometropia than stereoacuity at near. Myopic anisometropia involving “against the rule” astigmatism potentially affects binocularity more than anisometropia with regular astigmatism. A prompt correction of anisometropia of more than 2 D is needed in children to prevent the development of amblyopia.

Posterior chamber phakic intraocular lens for the correction of high myopic anisometropic amblyopia in adults

This study aims to evaluate the clinical results of posterior chamber implantable collamer lens (ICL) implantation in adults with high myopic anisometropic amblyopia. Thirteen patients aged 27.04±7.24y (range 19.2 to 42.5) were studied. ICL implantation was performed in 13 amblyopic eyes. The mean myopic anisometropia was significantly dropped from -10.70±3.02 D preoperatively to +0.09±1.67 D at 1mo postoperatively. The logMAR CDVA at 3d, 1, 3 and mean 9mo postoperatively improved by a mean of 1.69, 2.50, 3.01 and 3.00 lines and gained more than 2 lines accounted for 23.08% (3 eyes), 41.67% (5 eyes), 63.63% (7 eyes) and 55.56% (5 eyes), respectively. The contrast sensitivity of amblyopic eyes was significantly increased after surgery. Four patients partially recovered near stereopsis (400″ to 100″). There was no severe complications were observed. ICL implantation alone can improve vision, contrast sensitivity, and partial restoration of binocular vision in adult patients with high myopic anisometropia.

Photorefractive Keratectomy for Myopic Anisometropia: A Retrospective Study on 18 Children

Purpose

To evaluate the safety and efficacy of photorefractive keratectomy (PRK) performed under topical anesthesia in children with myopic anisometropia.

Methods

Medium to high unilateral myopia was corrected in 18 patients by PRK. At the time of surgery patients were between 7 and 17 years of age (mean 10 years). All the surgical procedures were performed under topical anesthesia. Pre- and postoperative data regarding visual acuity, eye alignment, and binocular vision were analyzed.

Results

The mean correction (SE) obtained with excimer laser was −8.21 D (range: −2.25 to −14.50, SD 3.90). The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 20/70, and the postoperative mean BSCVA was 20/50. A significant difference was observed between the arithmetic mean of the preoperative and postoperative BSCVA (p=0.001). Two of 18 patients improved stereopsis; furthermore, surgery variation strabismus was registered in 33.3% of the patients, following PRK. Patients were followed up for a mean of 39 months.

Conclusions

The treatment of medium to high unilateral myopia with PRK under local anesthesia was found effective and safe in pediatric and adolescent patients. This procedure may improve ocular alignment and stereopsis. Further studies are needed to increase the patient experience and extend follow-up time in order to assess the long-term stability of the results.

Femtosecond laser corneal refractive surgery for the correction of high myopic anisometropic amblyopia in juveniles

AIM

To evaluate the effects of femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small-incision lenticule extraction (SMILE) to correct high myopic anisometropic amblyopia in juvenile patients.

METHODS

From November 2013 to January 2015, 33 amblyopic patients with high myopic anisometropic amblyopia were studied. FS-LASIK (30 eyes) or SMILE (3 eyes) was performed in the amblyopic eyes. Visual acuity, refraction, contrast sensitivity, stereoacuity and complications were evaluated. Patients completed follow-up examinations at 3d, 1mo, 3mo and the last follow-up time (mean 8.17±3.23mo) after surgery.

RESULTS

The mean age at surgery was 9.04±3.04y (range 6-16y). The mean spherical equivalent in the amblyopic eyes was significantly decreased from -10.00±2.39 D preoperatively to -0.06±1.06 D at 1mo, -0.19±1.33 D at 3mo and -0.60±1.43 D at approximately 8mo postoperatively (P<0.05 for all). The mean myopic anisometropia was significantly decreased from -9.45±2.33 D preoperatively to +0.37±1.48 D at 1mo, -0.46±1.47 D at 3mo and -0.09±1.83 D at approximately 8mo (P<0.05 for all). The logarithm of the minimum angle of resolution (logMAR) for uncorrected and corrected distance visual acuity (UDVA and CDVA, respectively) of the amblyopic eye improved from 1.74±0.35 and 0.98±0.63 preoperatively to 0.45±0.31 and 0.41±0.33 at approximately 8mo after surgery, respectively. The logMAR CDVA at 3d, 1, 3 and 8mo postoperatively improved by means of 1.42, 2.22, 2.96, and 4.39 lines, and a gain of more than two lines accounted for 45%, 50%, 74% and 86% of all patients, respectively. The contrast sensitivity of both amblyopic eyes and dominant eyes at 0.5, 2, 8 cycles per degree was significantly improved postoperatively (P<0.05 for all). Of the 33 pediatric patients, no patients had near stereopsis preoperatively and seven patients (21.2%) recovered near stereopsis (400″ to 60″) at approximately 8mo after surgery. No intraoperative or postoperative complications occurred in any patient.

CONCLUSION

FS-LASIK or SMILE can be promising alternative methods to correct high myopic anisometropic amblyopia in juvenile patients who have failed with traditional approaches.

Phakic Intraocular Collamer Lens (Visian ICL) Implantation for Correction of Myopia in Spectacle-Aversive Special Needs Children

PURPOSE

A subset of children with high anisometropia or isoametropia and neurobehavioral disorders have chronic difficulties with spectacle or contact lens wear. We report the results of refractive surgery in a series of these children treated using bilateral or unilateral intraocular collamer lens (Visian ICL) implantation for moderate to high myopia.

DESIGN

Prospective nonrandomized cohort study.

METHODS

Clinical course and outcome data were collated prospectively for 40 implanted eyes in 23 children (mean age 10.2 ± 5.3 years, range, 1.8-17 years). Myopia ranged from -3.0 to -14.5 diopters (D), mean -9.2 ± 3.5 D. Goal refraction was plano to +1 D. Correction was achieved by sulcus implantation of a Visian ICL (STAAR Surgical, Monrovia, California, USA) under general anesthesia. Mean follow-up was 15.1 months (range, 6-22 months).

RESULTS

Thirty-five eyes (88%) were corrected to within ±1.0 D of goal refraction; the other 5 (12%) were corrected to within 1.5 D. Uncorrected distance visual acuity improved substantially in all eyes (from mean 20/1050 [logMAR 1.72] to mean 20/42 [logMAR 0.48]). Spherical regression at last follow-up was an average of +0.59 D. Visuomotor comorbidities (eg, amblyopia, nystagmus, foveopathy, optic neuropathy) accounted for residual postoperative subnormal visual acuity. Thirteen of the 23 children (57%) had a neurobehavioral disorder (eg, developmental delay/intellectual disability/mental retardation, Down syndrome, cerebral palsy, autism spectrum disorder). Eighty-five percent (11/13) of those children were reported to have enhanced visual awareness, attentiveness, or social interactions. Endothelial cell density was measureable in 6 cooperative children (10 eyes), showing an average 1% decline. Central corneal thickness, measured in all children, increased an average of 8 μm. Two children (8%) required unplanned return to the operating room on the first postoperative day to alleviate pupillary block caused by a nonpatent iridotomy. No other complications were encounterd.

CONCLUSION

Visian ICL implantation improves visual function in special needs children who have moderate to high myopia and difficulties wearing glasses or contact lenses.

Phakic posterior chamber intraocular lens for unilateral high myopic amblyopia in Chinese pediatric patients

AIM

To assess the outcomes of posterior chamber implantable collamer lens (ICL) implantation in Chinese pediatric patients with unilateral high myopic amblyopia.

METHODS

Eleven eyes of 11 amblyopic patients aged 11.02±3.34y underwent ICL (model V4, Staar Surgical Inc.) implantation to treat unilateral anisometropia were studied. Visual acuity, cycloplegic refraction, contrast sensitivity, stereopsis, intraocular pressure (IOP), vaulting, corneal endothelial cell count and complications were evaluated. Patients completed follow-up at 3d, 1, 3mo and the last follow-up time (mean 8.18±2.82mo) after surgery.

RESULTS

The mean myopic anisometropia was -13.70±3.25 D preoperatively and +0.69±2.63 D at 8mo postoperatively. The logMAR corrected distance visual acuity (CDVA) of the amblyopic eye was 1.51±0.72 preoperatively and 0.75±0.40 at 8mo postoperatively. The logMAR CDVA at 3d, 1, 3 and 8mo postoperatively improved by a mean of 0.64, 1.55, 1.82 and 2.64 lines and gained more than 2 lines accounted for 18%, 45%, 45%, 64%, respectively. The contrast sensitivity of 0.5, 1 and 2 cpd in amblyopic eyes was significantly increased after surgery. No patient had near stereopsis recovery. The vaulting at 3 and 8mo was significantly lower than that at 1mo postoperatively. No other intraoperative or postoperative complications were observed, except an acute pupillary block glaucoma happened in a patient at two weeks postoperatively.

CONCLUSION

This short-term results indicate that ICL implantation can be a promising alternative therapy for high myopic anisometropic amblyopia in pediatric patients who have failed with conventional treatments and not suitable to corneal refraction surgery.

Effect of Anisometropia on the Predictability and Accuracy of Refractive Surgery

PURPOSE

To evaluate the predictability and accuracy of refractive surgery among adults with myopic anisometropia.

METHODS

Consecutive cases of myopic eyes that underwent bilateral laser-assisted in situ keratomileusis (LASIK) or bilateral photorefractive keratectomy (PRK) during a 12-year period in a single center were included. Myopic anisometropia was defined as a difference greater than 1.5 D in spherical equivalent between eyes preoperative.

RESULTS

A total of 10,046 paired, operated nonamblyopic eyes of 5023 patients were analyzed. Of these, 472 eyes of 236 (4.7%) patients had myopic anisometropia without amblyopia, and 9574 eyes of 4787 patients served as isometropic controls. After refractive surgery, in the anisometropic group the more myopic eye was corrected by +0.47 ± 0.78 (D) more than the contralateral eye (P < 0.0001). Relative to the target refraction, the more myopic eye was overcorrected by 0.21 ± 0.79 D compared with an undercorrection of 0.16 ± 0.60 D in the less myopic contralateral eye (P < 0.0001) and compared with an undercorrection of 0.15 ± 0.62 D in the isometropic controls (P < 0.0001). Additionally, the variability in the correction of the more myopic eyes was significantly higher compared with the less myopic contralateral eyes and isometropic controls (P < 0.0001). These trends were evident both in PRK and LASIK treatments. The effect of anisometropia was found to be independent of the magnitude of preoperative myopia or surgeon identity.

CONCLUSIONS

The more myopic eye of anisometropes undergoing refractive surgery has lower predictability and accuracy and tends to be overcorrected, whereas the less myopic eye has outcome similar to isometropic controls. These results suggest that refractive surgery nomograms should take into account anisometropia.

Laser-assisted subepithelial keratectomy (LASEK) versus photorefractive keratectomy (PRK) for correction of myopia

BACKGROUND

Myopia (near-sightedness or short-sightedness) is a condition in which the refractive power of the eye is greater than required. The most frequent complaint of people with myopia is blurred distance vision, which can be eliminated by conventional optical aids such as spectacles or contact lenses, or by refractive surgery procedures such as photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK). PRK uses laser to remove the corneal stroma. Similar to PRK, LASEK first creates an epithelial flap and then replaces it after ablating the corneal stroma. The relative benefits and harms of LASEK and PRK, as shown in different trials, warrant a systematic review.

OBJECTIVES

The objective of this review is to compare LASEK versus PRK for correction of myopia by evaluating their efficacy and safety in terms of postoperative uncorrected visual acuity, residual refractive error, and associated complications.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision group Trials Register) (2015 Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to December 2015), EMBASE (January 1980 to December 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to December 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 December 2015. We used the Science Citation Index and searched the reference lists of the included trials to identify relevant trials for this review.

SELECTION CRITERIA

We included in this review randomized controlled trials (RCTs) comparing LASEK versus PRK for correction of myopia. Trial participants were 18 years of age or older and had no co-existing ocular or systemic diseases that might affect refractive status or wound healing.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all reports and assessed the risk of bias of trials included in this review. We extracted data and summarized findings using risk ratios and mean differences. We used a random-effects model when we identified at least three trials, and we used a fixed-effect model when we found fewer than three trials.

MAIN RESULTS

We included 11 RCTs with a total of 428 participants 18 years of age or older with low to moderate myopia. These trials were conducted in the Czech Republic, Brazil, Italy, Iran, China, Korea, Mexico, Turkey, USA, and UK. Investigators of 10 out of 11 trials randomly assigned one eye of each participant to be treated with LASEK and the other with PRK, but did not perform paired-eye (matched) analysis. Because of differences in outcome measures and follow-up times among the included trials, few trials contributed data for many of the outcomes we analyzed for this review. Overall, we judged RCTs to be at unclear risk of bias due to poor reporting; however, because of imprecision, inconsistency, and potential reporting bias, we graded the quality of the evidence from very low to moderate for outcomes assessed in this review.The proportion of eyes with uncorrected visual acuity of 20/20 or better at 12-month follow-up was comparable in LASEK and PRK groups (risk ratio (RR) 0.98, 95% confidence interval (95% CI) 0.92 to 1.05). Although the 95% CI suggests little to no difference in effect between groups, we judged the quality of the evidence to be low because only one trial reported this outcome (102 eyes). At 12 months post treatment, data from two trials suggest no difference or a possibly small effect in favor of PRK over LASEK for the proportion of eyes achieving ± 0.50 D of target refraction (RR 0.93, 95% CI 00.84 to 1.03; 152 eyes; low-quality evidence). At 12 months post treatment, one trial reported that one of 51 eyes in the LASEK group lost one line or more best-spectacle corrected visual acuity compared with none of 51 eyes in the PRK group (RR 3.00, 95% CI 0.13 to 71.96; very low-quality evidence).Three trials reported adverse outcomes at 12 months of follow-up or longer. At 12 months post treatment, three trials reported corneal haze score; however, data were insufficient and were inconsistent among the trials, precluding meta-analysis. One trial reported little or no difference in corneal haze scores between groups; another trial reported that corneal haze scores were lower in the LASEK group than in the PRK group; and one trial did not report analyzable data to estimate a treatment effect. At 24 months post treatment, one trial reported a lower, but clinically unimportant, difference in corneal haze score for LASEK compared with PRK (MD -0.22, 95% CI -0.30 to -0.14; 184 eyes; low-quality evidence).

AUTHORS' CONCLUSIONS

Uncertainty surrounds differences in efficacy, accuracy, safety, and adverse effects between LASEK and PRK for eyes with low to moderate myopia. Future trials comparing LASEK versus PRK should follow reporting standards and follow correct analysis. Trial investigators should expand enrollment criteria to include participants with high myopia and should evaluate visual acuity, refraction, epithelial healing time, pain scores, and adverse events.

Refractive Surgery in Children

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

Pediatric refractive surgery: corneal and intraocular techniques and beyond

Refractive surgery has now been used successfully to treat severe anisometropia and isoametropia associated with amblyopia in children who cannot wear standard spectacles or contact lenses. Extraocular techniques include photorefractive keratectomy, laser-assisted subepithelial keratomileusis, and laser-assisted in situ keratomileusis. Intraocular techniques include refractive lensectomy and phakic intraocular lenses and are still being investigated in children for refractive errors outside the treatment dose capabilities of the excimer laser. This workshop discusses the various techniques, how and when to use each, and their risks and benefits. Newer techniques currently being used in adults that may someday be used in children are also introduced.

Pediatric refractive surgery in evolution

With the advent of corneal refractive surgery using excimer laser technology, treatment for corneal and refractive disorders have advanced tremendously and become very precise and predictable. The use of these techniques in the treatment of corneal and refractive disorders in children, especially during the amblyogenic ages, would be invaluable. Numerous reports on refractive surgery in children have demonstrated that it can be performed safely and efficaciously in the pediatric population. However, controversy still exists whether it should be done in this population. We explore the available published data to address this controversy.

Laser refractive correction of myopia in visually impaired patients improves visual acuity

PURPOSE

To retrospectively evaluate the visual and refractive outcome of visually impaired adults treated with refractive surgery (photorefractive keratectomy or laser-assisted in situ keratomileusis).

METHODS

We searched a refractive surgery database comprising 1716 mildly visually impaired patients [best spectacle-corrected visual acuity (BSCVA) on a logMAR scale ≤ -0.1 (Snellen ≤ 0.8)] who had undergone either PRK or LASIK (n = 96). PRK patients who had visits at 5-7, 8-13 and 14-24 months postoperatively were selected. Eleven patients and nine PRK control myopic patients were found (cohort 1). From the same database, 41 visually impaired patients and 54 controls who had a postoperative control at 14-24 months postoperatively were chosen. These patients formed cohort 2.

RESULTS

Preoperatively, in cohort 1, the mean BSCVA on a logMAR scale was -0.15 ± 0.13 (Snellen 0.73 ± 0.16) in visually impaired patients and 0.04 ± 0.02 (Snellen 1.11 ± 0.17) in myopic controls. At 14-24 months postoperatively, the mean BSCVA improved to 0.05 ± 0.04 (Snellen 1.13 ± 0.10) in visually impaired patients and 0.05 ± 0.08 (Snellen 1.13 ± 0.21) in control patients. In cohort 2, preoperatively the mean BSCVA on a logMAR scale was -0.15 ± 0.12 (Snellen 0.74 ± 0.14) in visually impaired patients and 0.01 ± 0.03 (Snellen 1.04 ± 0.10) in myopic controls. At 14-24 months postoperatively, the mean BSCVA improved to 0.02 ± 0.07 (Snellen 1.06 ± 0.16) in visually impaired patients and 0.06 ± 0.06 (Snellen 1.15 ± 0.16) in control patients.

CONCLUSION

Refractive surgery improves BSCVA in visually impaired patients, possibly through plastic changes in the visual cortex. Consequently, refractive surgery may be used successfully for the treatment of visually impaired adults to enhance their visual acuity.

Surface ablation techniques

The ongoing quest for a safe, simple, effective, minimally invasive, and stable refractive surgical procedure to correct refractive errors has stimulated the development of surface ablation techniques and laser in situ keratomileusis. In this review, we describe the history, patient assessment, techniques, outcomes, and complications of surface ablation (photorefractive keratectomy, laser-assisted sub-epithelial keratectomy, epithelial laser-assisted in situ keratomileusis) and compare the results of various surface techniques. Surface ablation procedures will continue to evolve, with potential improvements in outcomes accompanying future sophisticated ablation profiles and laser technology.

Meta-analysis: clinical outcomes of laser-assisted subepithelial keratectomy and photorefractive keratectomy in myopia

PURPOSE

To examine possible differences in clinical outcomes between laser-assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) for myopia.

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

Patients from previously reported randomized controlled trials (RCTs) and comparative studies of LASEK and PRK with clinical outcomes.

METHODS

A comprehensive literature search was performed using the Cochrane Collaboration methodology to identify RCTs and comparative studies comparing LASEK and PRK for myopia.

MAIN OUTCOME MEASURES

Primary outcome parameters included uncorrected visual acuity (UCVA) of 20/20 or better, manifest refractive spherical equivalent (SE) within ± 0.50 diopters (D), final refractive SE, and final UCVA of 20/40 or worse. Secondary outcome parameters included healing time of corneal epithelium, postoperative pain, and corneal haze.

RESULTS

Twelve studies were identified and used for comparing PRK (499 eyes) with LASEK (512 eyes) for myopia. There were no significant differences in odds ratio (OR), weighted mean difference (WMD), and standardized mean difference (SMD) in the primary and secondary outcome measures. The final mean refractive SE (WMD, 0.00; 95% confidence interval [CI], -0.08 to 0.07; P = 0.95), manifest refractive SE within ± 0.50 D of the target (OR, 0.90; 95% CI, 0.63-1.29; P = 0.56), patients achieving UCVA of 20/20 or better (OR, 0.86; 95% CI, 0.61-1.20; P = 0.37), final UCVA of 20/40 or worse (OR, 1.26; 95% CI, 0.63-2.51; P = 0.52), re-epithelialization time (WMD, 0.08; 95% CI, -0.44 to 0.59; P = 0.77), and postoperative pain (SMD, 0.26; 95% CI, -0.20 to 0.72; P = 0.27) were analyzed. However, LASEK-treated eyes showed less corneal haze at 1 month after surgery (WMD, 0.25; 95% CI, 0.10-0.39; P = 0.0007) and 3 months after surgery (WMD, 0.14; 95% CI, 0.01-0.26; P = 0.03) compared with PRK. No statistically significant difference was observed between the 2 groups at 6 months after surgery (WMD, 0.14; 95% CI, -0.02 to 0.30; P = 0.08).

CONCLUSIONS

In this meta-analysis, LASEK-treated eyes had no significant benefits over PRK-treated ones with regard to clinical outcomes. Less corneal haze was observed in LASEK-treated eyes at 1 to 3 months after surgery.

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.

LASIK correction of vision in adults with unilateral amblyopia

PURPOSE

to evaluate the effects of laser refractive surgery in adult patients with mild to moderate amblyopia due to anisometropic myopia.

METHODS

a retrospective review of 30 patients (60 eyes) with unilateral amblyopia (corrected distance visual acuity [CDVA] 0.6 or worse) who underwent simultaneous bilateral laser vision correction using the Technolas 217z excimer laser (Bausch & Lomb) was performed. Mean patient age was 31.03 ± 10.05 years (range: 18 to 53 years). Visual outcomes in the amblyopic eye were compared with those in the fellow nonamblyopic control eye of the same patient.

RESULTS

mean preoperative CDVA improved in amblyopic eyes from 0.50 ± 0.13 to 0.57 ± 0.20 postoperatively (average gain of 0.075 ± 0.14; P=.007) and improved from 0.92 ± 0.12 preoperatively to 0.93±0.15 after surgery (mean gain of 0.013 ± 0.14; P=.603) in the fellow nonamblyopic eyes. The safety index was significantly greater in the amblyopic eyes compared with the nonamblyopic fellow eyes (1.15 ± 0.30 vs 1.02 ± 0.15, P=.035), therefore, no difference was noted in efficacy (P=.913). Five of 30 eyes with mild to moderate amblyopia gained 2 to 4 lines of CDVA.

CONCLUSIONS

laser refractive surgery for myopic correction was found to be safe and effective in eyes with mild to moderate amblyopia.

Laser in situ keratomileusis for treated myopic anisometropic amblyopia in children

PURPOSE

To evaluate the effects of laser in situ keratomileusis (LASIK) in decreasing myopic anisometropia in children with spectacles or contact lens intolerance and its validity in facilitating treatment of resultant myopic anisometropic amblyopia.

PATIENTS AND METHODS

LASIK was performed in 18 eyes of 18 children having myopic anisometropic amblyopia not successfully treated with the standard amblyopia treatment for 6 months. Children were followed up at 1 week, 1, 2, 6, 12, 18 and 24 months. Postoperative amblyopia therapy was continued with occlusion of the dominant eye for 6 h daily for the first 3 months and then for 4 h per day as long as possible.

RESULTS

The mean spherical equivalent refraction in the operated eye had reduced significantly from -9.08 ± 1.86D preoperatively to -0.97 ± 1.16D at 2 years postoperatively. The mean spherical equivalent in the non-operated fellow eye was -1.0 ± 1.15D preoperatively and -2.50 ± 1.15D at 2 years. The mean spherical equivalent myopic anisometropia was -7.75 ± 2.25D preoperatively and -0.50 ± 0.31D at 2 years, representing a 93.5% reduction in myopic anisometropia. The mean regression value was -2.28 ± 1.62D, however, 18 eyes (72%) were within 3.0D of the fellow eye. The mean BCVA was significantly improved from 0.72 ± 0.13 preoperatively to 0.47 ± 0.17 by 2 years after LASIK with amblyopia treatment.

CONCLUSION

LASIK is a safe and effective alternative method for correcting myopic anisometropic amblyopia, especially in children with spectacles or contact lens intolerance, with more better visual acuity and binocular vision.

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

PURPOSE

To summarize the evolution of the treatment of pediatric refractive errors, with an emphasis on recent advancements in the use of refractive surgery to treat children.

DESIGN

Literature review.

METHODS

We searched MEDLINE (1950 through October 2007), the Cochrane library (December through October 2007), and the Cumulative Index for Nursing and Allied Health Literature (December 1982 through October 2007) for English language articles using the following search strategy with MeSH terms and key words: pediatric refractive errors and amblyopia, anisometropia, hyperopia, myopia, laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), laser epithelial keratomileusis (LASEK), excimer laser, refractive intraocular lens (IOL). We also searched the bibliographies of all identified articles.

RESULTS

No multicenter, long-term, controlled trial has been published on the use of refractive surgery in children. The current literature shows that LASIK, PRK, and LASEK show promising results in children with refractive amblyopia over the intermediate follow-up period. Corneal haze and myopic regression are the main complications, especially in very high myopia (> 12 diopters). In such patients with extremely high myopia, small studies have reported phakic IOLs or clear lens extraction with or without IOL implantation to be a useful alternative.

CONCLUSIONS

Refractive surgery is appropriate in children with severe anisometropia or bilateral high ametropia that is resistant to conventional therapy. More information is needed before pediatric refractive surgery can be widely adopted by the ophthalmic community. This could be achieved with a large, prospective, multicenter, randomized, controlled clinical trial.

Phakic intraocular lens correction of high ametropia in children with neurobehavioral disorders

PURPOSE

A subset of children with high ametropia and neurobehavioral disorders have chronic difficulties with spectacle or contact lens wear. We report the results of refractive surgery in a series of these children treated using bilateral or unilateral phakic intraocular lenses (IOLs) for ametropia >10 D.

METHODS

Clinical course and outcome data were collated prospectively in a group of 12 children (mean age, 10.1 years; range, 4-17 years) with neurobehavioral disorders exacerbated by poor compliance with spectacles. Myopia in 18 eyes ranged from -10.0 to -22.75 D (mean, -15.2 D) and in 2 hyperopic eyes from +10.25 to +10.75 (mean, +10.5 D). Goal refraction was approximately 0 to +1 D. Correction was achieved by implantation of an iris-enclaved phakic IOL under general anesthesia. Mean follow-up was 9.1 months (range, 3-15 months).

RESULTS

Myopia correction averaged 14.5 D and hyperopia correction 9.4 D. Eighty-six percent of eyes (17/20 eyes) were corrected to within +/- 1 D of emmetropia and the remaining 14% (3 eyes) to within +/- 2 D. Uncorrected visual acuity improved substantially in all 20 eyes (60-fold; from a mean of 20/3400 to a mean of 20/57). Ocular comorbidities in each child accounted for residual postoperative, subnormal visual acuity (eg, amblyopia, nystagmus, albinism, regressed retinopathy of prematurity). Visual functions (measured using a 23-item validated survey) improved. One eye required IOL exchange; no other clinically significant complications have been encountered.

CONCLUSIONS

Phakic IOL implantation improves visual function substantially in neurobehaviorally impaired children who have high ametropia and difficulties wearing glasses.

Outcomes of 6 hour part-time occlusion treatment combined with near activities for unilateral amblyopia

PURPOSE

To evaluate the outcome of the part-time occlusion therapy with near activities in monocular amblyopic patients according to gender, age, severity of amblyopia, and the cause of amblyopia.

METHODS

Fifty eight patients who were prescribed part-time occlusion therapy with near activity from July 1998 to October 2004, were included in this retrospective study. All patients were divided into groups by gender, age, severity of amblyopia, and the cause of amblyopia. Main outcome measures were best corrected visual acuity, line improvement, and success rate.

RESULTS

At the end of patch therapy, visual acuity improved from baseline by an average of 3.2+/-2.5 lines (0.33+/-0.26 log MAR), and follow-up period was 19.71+/-14.61 months (1.62+/-1.20 years). At the last follow-up, visual acuity improved from baseline by an average of 3.7+/-2.4 lines (0.38+/-0.26 log MAR), and follow-up period was 37.41+/-25.83 months (3.08+/-2.12 years). The success rate was 86% (50 patients) at the end of patch therapy. In 44 patients out of 50 patients (88%), the visual acuity was maintained. While 43 patients out of 47 patients who were less than 7 years old (91%) achieved success, 7 patients out of 11 patients 7 years or older (64%) achieved success (p=0.035).

CONCLUSIONS

Six-hour part-time occlusion treatment combined with near activities appears to be favorable in treating 58 children during follow-up of mean 3.08 years. The significant factor was the age at initial treatment.

Facilitation of amblyopia management by laser in situ keratomileusis in high anisometropic hyperopic and myopic children

PURPOSE

To assess the efficacy of laser in situ keratomileusis (LASIK) in facilitating amblyopia management of children from 6 to 14 years old, with high hyperopic and myopic anisometropia.

PATIENTS AND METHODS

Between 2000 and 2005, 42 children with high hyperopic anisometropic amblyopia and 32 children with high myopic anisometropic amblyopia underwent LASIK to reduce their anisometropia. LASIK was performed under topical or general anesthesia. Pre- and postoperative best-corrected visual acuity, cycloplegic refraction, and binocular vision were recorded. Follow-up ranged from 6 months to 3 years, the averages of which were 17.45 months in the hyperopic group and 18.31 months in myopic group.

RESULTS

Hyperopic anisometropia correction ranged from +3.50 D to +7.75 D, and the mean postoperative anisometropia was +0.56 +/- 0.75 D at 3 years. Myopic anisometropia correction ranged from -15.75 to -5.00 D and the mean postoperative anisometropia at 3 years was -2.20 +/- 1.05 D. The best-corrected visual acuity for distance and reading in the myopic group improved from 0.4 +/- 0.25 and 0.58 +/- 0.27, respectively, before surgery to 0.59 +/- 0.28 and 0.96 +/- 0.35, respectively, 3 years after surgery. In the hyperopic group, best-corrected visual acuity for distance and reading improved from 0.23 +/- 0.21 and 0.34 +/- 0.32, respectively, before surgery to 0.53 +/- 0.31 and 0.80 +/- 0.33, respectively, 3 years after surgery. The proportion of patients who had stereopsis increased from 19.1% preoperatively to 46.7% postoperatively in the hyperopic group and from 19% to 89% in the myopic group.

CONCLUSIONS

LASIK reduced high hyperopic and myopic anisometropia in children, thus facilitating amblyopia management and improving their visual acuity and stereopsis.