Refractive surgery for children: excimer laser, phakic intraocular lens, and clear lens extraction

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.

Clear lens extraction and refractive lens exchange for the treatment of amblyopia

Treatment of amblyopia typically involves spectacles or penalization of the nonamblyopic eye with occlusive patching or pharmacological penalization. However, these methods can be ineffective or difficult in certain children who may be unable to tolerate or are poorly compliant with such therapies. Untreated high refractive error can result in dense amblyopia, and thus, other treatment methods are necessary in this subset of children. With technological advances in ocular surgery, clear lens extraction (CLE) and refractive lens exchange (RLE) have emerged as popular alternative treatments for amblyopia, as they may avoid some of the challenges surrounding traditional methods. CLE involves lensectomy for refractive purposes in patients without cataracts, while RLE involves lensectomy followed by intraocular lens implantation. The purpose of this review was to summarize the use of CLE and RLE for the treatment of amblyopia in the pediatric population, discussing indications, techniques, treatment outcomes, safety, and potential complications.

Anterior Chamber Iris-Fixated Phakic Intraocular Lens Implantation for Treatment of High Anisometropia in Children: Long-term Results

PURPOSE

To evaluate the long-term efficacy of anterior chamber iris-fixated phakic intraocular lens (PIOL) implantation in the treatment of high myopic (> -9.00 diopters [D]) or hyperopic (> +6.00 D) anisometropia in children with intolerance to spectacles or contact lenses.

METHODS

A total of 58 children with anisometropic myopia (range: -9.25 to -18.50 diopters [D]) and 13 children with anisometropic hyperopia (range: +6.00 to +8.50 D) underwent unilateral iris-claw PIOL implantation from 2008 to 2018. The mean age was 6.7 years. The mean follow-up was 38.5 months. Target refraction was emmetropia.

RESULTS

The cycloplegic refraction (mean spherical equivalent) improved from -12.47 D (range: -9.25 to -18.50 D) to -0.73 D (range: +0.75 to -1.50 D) in myopic eyes and reduced from +7.15 D (range: +6.00 to +8.50 D) to +0.94 D (range: -0.50 to + 1.75 D) in hyperopic eyes. Eighty-four percent of eyes were corrected to within ±1.00 D of emmetropia. The mean uncorrected distance visual acuity (UDVA) improved from 1.74 ± 0.36 to 0.45 ± 0.28 logarithm of the minimum angle of resolution (logMAR) (P = .0014). The mean corrected distance visual acuity (CDVA) changed from 0.68 ± 0.32 to 0.27 ± 0.15 logMAR (P = .02179). The safety index was 2.18 and the efficacy index was 1.51. The mean pre-operative endothelial cell count of 2,874.7 cells/mm² changed to 2,685.3 cells/mm² at 2 to 6 years postoperatively. Binocular vision quality was improved in 55 patients. No patient had serious complications or lost any Snellen lines of CDVA.

CONCLUSIONS

Iris-fixated PIOL implantation is an effective and safe method in the treatment of high anisome-tropic myopia and hyperopia and amblyopia in pediatric patients who are noncompliant with spectacles or contact lenses. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

The Influence of 0.5% Tropicamide on Anterior Segment Parameters With CASIA2 in Emmetropic, Myopic, and Hyperopic Eyes

Aim: To evaluate the effects of 0.5% tropicamide on anterior segment parameters with the CASIA2 imaging device in emmetropic, myopic, and hyperopic eyes.

Methods: In this prospective study, a total of 125 subjects (34 emmetropic subjects, 57 myopic subjects, and 34 hyperopic subjects) at the Shanghai Eye and ENT Hospital of Fudan University were recruited from June 2021 to September 2021. The 0.5% tropicamide solution was used once every 5 min a total of 5 times for cycloplegia. The anterior segment parameters were recorded by CASIA2 before and after cycloplegia. Changes in anterior segment parameters were compared among the three refractive groups.

Results: Crystalline lens rise (CLR) and crystalline lens thickness (CLT) significantly decreased in all three refractive groups after cycloplegia (all p < 0.01). The anterior radius of lens (ARL) and anterior chamber depth (ACD) significantly increased in all three refractive groups after cycloplegia (all p < 0.01). Posterior radius of lens (PRL) significantly increased in hyperopic eyes after cycloplegia (p < 0.01) while it remained unchanged in emmetropic eyes and myopic eyes. Central corneal thickness (CCT), anterior chamber width (ACW), lens decentration (LD), and lens tilt (LT) remained unchanged after cycloplegia in all three refractive groups (all p > 0.05). Changes in CLR, CLT, ARL, PRL, and ACD in hyperopic eyes were greater than those in emmetropic eyes and myopic eyes (all p < 0.05).

Conclusion: Apart from various changes in anterior segment parameters after application by 0.5% tropicamide in all three refractive groups, significant changes in CLR, CLT, ARL, PRL, and ACD in hyperopic eyes should be noted for proper clinical interpretation.

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.

Ophthalmologic findings in the Cornelia de Lange syndrome

BACKGROUND

Cornelia de Lange syndrome (CdLS) is a congenital disorder characterized by multisystem abnormalities, including distinct ophthalmologic findings. In recent years, advances in molecular genetics have begun to provide new insight into the characterization of these clinical features and the genetic basis of the syndrome.

MATERIALS AND METHODS

We included 37 articles that were identified through an electronic search in PubMed and through the reference lists of previously conducted reviews. Studies of 30 or more patients were used to report frequencies of common and less common findings. Genotype-phenotype studies were used to provide additional information when available.

RESULTS

Ocular anomalies are present in most patients with CdLS. Common findings include long eyelashes, synophrys, hirsutism of the eyebrows, peripapillary pigment ring, and myopia. Less common findings include hyperopia, ptosis, blepharitis, short palpebral fissure length, down-slanting palpebral fissures, mild microcornea, strabismus, nystagmus, and optic nerve abnormalities.

CONCLUSIONS

This review provides a comprehensive summary of the ophthalmologic findings in CdLS. Mutations in certain genes may be associated with specific ocular abnormalities, although future genotype studies are needed to further characterize these relationships.

Influences of topical cyclopentolate on anterior chamber parameters with a dual-Scheimpflug analyzer in healthy children

PURPOSE

To evaluate the changes of anterior segment parameters following the topical instillation of cyclopentolate hydrochloride 1% with the Galilei dual-Scheimpflug analyzer (GSA) (Ziemer Ophthalmology Co., Port, Switzerland) in healthy children.

METHODS

Fifty children (29 boys, 21 girls) were evaluated before and 60 minutes after instillation of three drops of 1% cyclopentolate hydrochloride using the GSA. The measurements before and after cycloplegia, including anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), central corneal thickness (CCT), and pupil size, were evaluated using the paired t test.

RESULTS

The mean age of the patients was 10.27 ± 3.32 years (range: 5 to 15 years). Measurements between the two sessions were significantly different for all parameters (P < .05), except for CCT (P > .05).

CONCLUSIONS

The GSA demonstrated a statistically significant increase in ACD, ACV, ACA, and pupil size following the topical application of cyclopentolate hydrochloride 1%. These results should be considered during biometric measurement and refractive surgery planning.

Laser in situ keratomileusis in 2012: a review

Laser in situ keratomileusis (LASIK) is a safe and effective treatment for refractive error. A combination of technological advances and increasing surgeon experience has served to further refine refractive outcomes and reduce complication rates. In this article, we review LASIK as it stands in late 2012: the procedure, indications, technology, complications and refractive outcomes.

Foldable iris-fixated intraocular lens implantation in children

PURPOSE

  To describe the results of foldable iris-fixated intraocular lens (IOL) implantation in children.

METHODS

  Children with high bilateral or unilateral myopia who were intolerant of spectacle or contact lens correction were implanted with an iris-fixated foldable IOL and prospectively followed. We measured pre- and postoperative visual acuity, refraction, endothelial cell density (ECD) and National Eye Institute Visual Functioning Questionnaire-25.

RESULTS

  Eleven eyes of six children were implanted. Indications were high bilateral myopia in children with comorbid neurobehavioural disorders, high anisometropia and high myopic astigmatism. Mean preoperative spherical equivalent (SE) refraction was -14.6 dioptres (D)±4.2 SD. Mean follow-up was 15 months. Postoperative SE refraction was -2.40 D±2.40 SD. Corrected distance visual acuity (CDVA) improved from mean logMAR 0.84±0.4 SD to postoperative 0.67±0.34 SD (p=0.005). CDVA was reduced because of coexistent ocular disorders and amblyopia. Vision-related quality of life (QOL) measures improved significantly. There were no intraoperative or postoperative serious complications.

CONCLUSION

  Foldable iris-fixated IOL insertion can give a significant improvement in vision and in vision-related QOL in a subset of paediatric patients with special refractive needs who are intolerant to conventional treatment. Long-term follow-up is required for monitoring of ECD.

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.

Influences of cyclopentolate hydrochloride on anterior segment parameters with Pentacam in children

PURPOSE

To investigate the effects of cyclopentolate hydrochloride 1% on the main numerical parameters of anterior segment with Pentacam rotating Scheimpflug camera in children.

SETTING

Ege University Faculty of Medicine, Department of Ophthalmology.

METHODS

Pentacam measurements of 50 (23 boys and 27 girls) children before and after 45 min of cyclopentolate hydrochloride 1% instillation were performed and compared with 31 (17 boys and 14 girls) no medication instilled control group. Measurements of the control group (cycloplegia-free) were taken at two separate sessions with 45-min intervals. For comparison of the test parameters, paired t-test in the groups and unpaired t-test in between the groups were used.

RESULTS

Mean ages in the study and control groups were 10.06 ± 2.87 (range 6 and 16 years) and 9.87 ± 2.72 (range 6 and 16 years), respectively, and the difference was statistically insignificant (p > 0.05). In the study group, measurements between two sessions were significantly different for the parameters of anterior chamber depth (ACD), anterior chamber volume (ACV) and central corneal thickness (CCT) (p < 0.05), whereas none of the parameters was different between two sessions for control group.

CONCLUSIONS

Cyclopentolate hydrochloride 1% instillation leads to significant decrement in CCT. ACD and ACV are the other important refractive parameters that increase significantly after cycloplegia. Effects of cycloplegia on these parameters for Pentacam measurements should be regarded for proper clinical interpretation in children.

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.

Phakic anterior chamber intraocular lens (Verisyse) implantation in children for treatment of severe ansiometropia myopia and amblyopia: Six-month pilot clincial trial and review of literature

Purpose:

The current study aims to evaluate both safety and efficacy of Verisyse^™ (AMO, Irvine, CA) phakic anterior chamber intraocular lens (IOL) in the reduction of clinically significant (>−8 D) myopic anisometropia in children who are noncompliant to traditional medical treatment including spectacle correction or contact lenses.

Design:

Retrospective interventional case series.

Methods:

Six anisometropic myopic pediatric patients in one practice were identified through chart-review. None of the patients were compliant with specatacle correction or contact lens wear and as a result had dense amblyopia of less than 20/400 by Snellen or Allen visual acuity (mean <20/400). All patients underwent Verisyse^™ phakic IOL implantation in the more myopic eye by one surgeon (AP). Pre- and post-operative visual acuity, anterior/posterior segment examination, stereoacuity, axial biometry measurements, cycloplegic refraction, and endothelial cell counts were performed in all patients whenever feasible.

Results:

The age of patients ranged from 5–11 years. The mean post-operative follow-up time was six months from the time of IOL insertion. Improvement in visual acuity >6 lines was achieved in four patients (mean visual acuity of 20/70 at six months). Improvement in stereoacuity was noted in all six patients (from total mean zero seconds-arc to six-months post-operative mean of 500 seconds-arc by randot stereoacuity testing). Improvement of >2 lines of visual acuity lines was achieved in the other two patients. No patient lost any lines of visual acuity. Enhanced physical activity, coordination, and improved social interaction were noted in patients and were reported by the parents. No intra/post-operative complications were noted.

Discussion:

Irreversible or intractable amblyopia secondary to severe anisometropic myopia is a serious medical concern in the pediatric population. Failure of compliance with contact lens therapy consistently leads to visual loss. Anterior chamber phakic IOLs may provide a safe alternative in treatment of noncompliant anisometropic myopic patients who do not accept spectacle wear or contact lens therapy.

Conclusion:

To reduce or eliminate highly significant anisometropic myopia in children who are noncompliant with traditional medical treatment, phakic anterior chamber IOL implantation may be considered as an alternative modality of treatment.