The fundamental purpose of excimer laser refractive surgery is to reduce refractive error. However, in some cases, excimer laser correction can be a primary indication for children with anisometropia due to hyperopia, high astigmatism, or both, when conventional therapy such as glasses or contact lenses cannot be used. In such cases, excimer laser refractive surgery can be used to decrease the chances of amblyopia or strabismus.1,2 The anatomic and functional development of the eye is completed by age 7 or 8 years, hence the use of excimer laser in children and adolescents is a clinically viable option to effectively treat amblyopia and strabismus.34 In this study, we report the results of excimer laser refractive surgery in children and adolescents with accommodative strabismus and refractive amblyopia.
PATIENTS AND METHODS
Sixty-three eyes of 46 patients underwent excimer laser refractive surgery over a 6-year period. Mean patient age was 12.65?2.1 years (range: 8 to 16 years). Spherical equivalent refraction (SE) ranged from +1.0 to +6.0 diopters (D) and astigmatism ranged from 1.0 to 5.5 D. Mild to moderate (I-II degrees, respectively) amblyopia was present in 44 eyes, the angle of deviation ranged from 10? to 45? in 30 patients, and disruption of binoculari ty was seen in 24 cases.
Patients underwent a complete ophthalmic examination including systemic work-up. Pre- and postoperative ophthalmic examinations included uncorrected visual acuity (UCVA), manifest and cycloplegic refractions, keratometry, slit-lamp microscopy, and corneal topography using the OPD-Scan (NIDEK, Gamagori, Japan). Postoperative examinations were performed at 1, 3, 6, and 12 months. Laser correction was based on the full cycloplegic refraction to avoid residual hyperopia postoperatively. LASIK was performed in all cases.5
Preoperative UCVA ranged from 0.04 to 1.0. Preoperative best spectacle-corrected visual acuity (BSCVA) ranged from 0.1 to 1.0. Postoperative UCVA ranged from 0.3 to 1.0. In this patient population, vision stabilized 3 to 6 months postoperatively. Postoperative UCVA was better that preoperative BSCVA in 44 (70%) of 63 eyes. In this group of eyes, the degree of amblyopia decreased in 24 cases and disappeared in 20 cases (Fig 1). It should be noted that no other form of amblyopia therapy was initiated on any patient during this study. For patients with strabismus, the angle of deviation was significantly reduced or eliminated by 3 to 6 months postoperatively (Fig 2). Twenty-one patients achieved binocularity 3 to 6 months postoperatively (Fig 3).
The results of this study show that the indications of excimer laser correction of hyperopia and hyperopic astigmatism can be expanded to include children with refractive amblyopia and strabismus. In some cases, excimer laser surgery is a viable and perhaps warranted intervention for children and adolescents at risk for amblyopia.67
The human eye is formed by early school age. We recommend observing this patient group for 6 to 12 months prior to any intervention to monitor refraction changes. Additionally, preteens' psycho-emotional status and intellectual abilities must also be taken into consideration when performing LASIK. We recommend LASIK to prevent the development of amblyopia in cases with severe anisometropia with high astigmatism, where refraction cannot be properly corrected with glasses (due to anisometropia) or contact lenses (due to high astigmatism).
In the patients with amblyopia treated in this study, a significant increase in UCVA was noted. We believe the use of excimer laser sculpting directly onto the cornea creates an integrated optical system that cannot be replicated with glasses or contact lenses, resulting in an improved optical image on the retina to realize the full visual potential in this patient population.
The angle of deviation was significantly decreased after treatment in many cases, leading to a resolution in strabismus and amblyopia. Prior to treatment, many patients included in this study had simultaneous or monocular vision, severe amblyopia, and a large angle of deviation even with glasses. Postoperatively, the majority of cases reverted to binocularity.8
Excimer laser correction of hyperopia and hyperopic astigmatism in children and adolescents has the potential to correct refractive errors, improve visual function in amblyopic eyes, correct accommodative strabismus, and improve binocular vision.
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