Pediatric Anisometropia: tacles, vision therapy, and occlusion. Case two Case Series and Review is anisometropia caused by organic vision loss from optic neuritis early in life. Case three is John D. Tassinari OD, FAAO, FCOVD an infant with hyperopic anisometropia and Diplomate Binocular Vision esotropia. The esotropia did not respond to Perception and Pediatric Optometry, spectacles and home based vision therapy. American Academy of Optometry Neonatal high bilateral hyperopia that Associate Professor Western converted to anisometropia because of early University of Health Sciences onset cosmetically invisible unilateral esotropia College of Optometry is speculated. Case four describes a boy Pomona, California diagnosed with hyperopic anisometropia at age 11 months coincident with a diagnosis of pseudoesotropia. His compliance with ARTICLE prescribed spectacles was spotty until age three years. An outstanding visual outcome ABSTRACT was achieved by age five years with spectacles Background only (no occlusion therapy). Case five concerns The etiology and natural course and history a boy who acquired hyperopic anisometropia of pediatric anisometropia are incompletely because one eye experienced increasing understood. This article reviews the literature hyperopia during his toddler years. His regarding pediatric anisometropia with much response to treatment, spectacles and part of the review integrated into a case series. time occlusion with home vision therapy, was The review and case reports are intended to outstanding. Case six is an infant diagnosed elevate clinical understanding of pediatric with 2.50 diopters of hyperopic anisometropia anisometropia including and especially at age six months. Monocular home based treatment outcomes. vison developmental activities, not glasses, were prescribed. Her anisometropia vanished Case Reports three months later. Case one is anisomyopia with amblyopia that resulted in a poor treatment outcome despite Conclusions outstanding compliance with prescribed spec- Pediatric anisometropia presents and responds to treatment in a variety of ways that challenge Correspondence regarding this article should be emailed to John D. Tassinari, OD, FAAO, FCOVD, at clinical care. Etiology and age of onset, which [email protected]. All statements are the author’s usually elude clinicians, can explain this variety. personal opinions and may not reflect the opinions of Additional research is required to improve the College of Optometrists in Vision Development, Vision Development & Rehabilitation or any institu tion clinical outcomes. or organization to which the authors may be affiliated. Permission to use reprints of this article must be obtained from the editor. Copyright 2020 College of Optometrists Pediatric anisometropia may be causative of, in Vision Development. VDR is indexed in the Directory or at the very least associated with, monocular of Open Access Journals. Online access is available at and binocular visual impairment. If anisometropia covd.org. https://doi.org/10.31707/VDR2020.6.1.p32. occurs during the sensitive period of visual Tassinari JD. Pediatric Anisometropia: Case Series and development, is of significant magnitude, Review. Vision Dev & Rehab 2020;6(1):32-56. chronic, and not treated in time, the visual abnormalities are lifelong. The natural course Keywords: Anisometropia, amblyopia, and history of anisometropia and its etiology vision therapy, occlusion are incompletely understood. One important 32 Vision Development & Rehabilitation Volume 6, Issue 1 • March 2020 but elusive consideration in the longitudinal shifted to anisometropia by age 3-years. course of pediatric anisometropia is age of Another longitudinal study showed that onset. Clinically, it is impossible to document anisometropia in infancy does not correlate age of onset because anisometropia, unlike with anisometropia at age 12-15 years, but age many forms of another amblyogenic condition, 5 year anisometropia correlates with adolescent strabismus, is invisible. Epidemiological anisometropia.6 evidence against neonatal onset persistent Age of onset is of particular interest in cases anisometropia comes from studies showing of non-transient anisometropia with abnormal an anisometropia prevalence among infants vision because of its link to severity of amblyopia and young children near 1%1-4-2%5,6 in and treatment prognosis.14-17 In broad terms, contradistinction to older pediatric populations persistent pediatric anisometropia appears to with an anisometropia prevalence ranging from be a largely acquired condition sometime after 6%6-9%.7,8 Atkinson et. al. acquired refractive age 1 year. For cases of persistent anisometropia data from over 8,000 infants age 6-8 months. that are an exception to this rule, and onset Per a criterion of > 1.50D, the anisometropia early in the first year of life, deep amblyopia prevalence was approximately 1%.1 Another and recalcitrant suppression of binocular vision definitive study of early in life ametropia (see Cases 1 and 3 below) is expected. found four anisometropes > 1.00D among 514 For cases of acquired non-transient ped- children age 1-48 months.2 The STARS cross ia tric anisometropia, how does the shift sectional population based study found one to anisometropia occur? Does the lesser child with anisometropia per a definition of ametropic eye begin with high ametropia equal > 2.00D among 615 children age 6-23 months.3 to the fellow eye then shift toward emmetropia Regarding older children, Hu et al’s recent study leaving the more ametropic eye behind (Case of over 6,000 children age 4-18 years found 7% 4 below)? This sequence seems most plausible anisometropia (≥1 diopter).8 given the proclivity for infant/toddler ametropia Another confounding age-of-onset variable to migrate toward emmetropia.1,2,5,13,18 Alter - is that transient and reducing anisometropia natively, the shift from isometropia to aniso- occurs during the first few years of life5,6,9-13 metropia occurs because the ametropia in one (see Case 6 below). Wood, Hodi, and Morgan’s eye worsens while the fellow eye does not. No longitudinal study found that all cases of doubt a 3rd chronological route for acquired anisometropia in infants younger than age 6 pediatric anisometropia is a combination. One months disappeared before age 12 months.5 eye shifts towards emmetropia while the fellow Similarly, Almeder et. al. found that among the shifts away (see Case 5 below). identified non-strabismic anisometropic infant Onset age and antecedent refractive subjects none had persistent anisometropia.11 changes aside, etiology of acquired pediatric Another longitudinal study showed 10% anisometropia remains a quandary. In basic terms, anisometropia prevalence at all age levels pediatric anisometropia is due to mismatched one through four years.10 This prevalence optical eye growth. If each eye functions in the carried through the ages because there same environment and participates in the same were anisometropic children who converted visual experiences, why does one eye stray to isometropia during the study time frame further from the emmetropization path than supplanted by children who acquired its fellow? It may be as simple as the optical anisometropia. Ingram and Barr’s longitudinal elements of the worse eye deviating further study found a similar result.9 Seven of their away from emmetropization per random twelve 1-year old anisometropes converted to biological and genetic variation. The eye and isometropia and eight of their 136 isometropes its attached neurology are structurally sound 33 Vision Development & Rehabilitation Volume 6, Issue 1 • March 2020 but the individual optical elements of the worse meridian, not the spherical equivalent, registers eye, for benign and idiopathic reasons, comply as the signal for axial elongation.28 Thus, an eye poorly with the rules of emmetropization. saddled with higher astigmatism than its fellow Support for a genetic contribution to eye concludes emmetropization with higher anisometropia etiology can be found in a hyperopia (Case 6 below). Bilateral and equal Vision in Preschoolers (VIP) study showing astigmatism that results in anisometropia may differences in the prevalence of anisometropia be understood as one eye possessing better among different racial/ethnic groups.19 Two emmetropization responsiveness in the face of known causes of faulty emmetropization in one astigmatic blur (Case 5 below). eye and therefore anisometropia are visual- This article presents a retrospective chart input depriving eye diseases18,20 (Case 2 below) review series of six pediatric anisometropia and unilateral strabismus, particularly unilateral cases that raise questions and discussions esotropia (Case 3 below).11,20-26 It is tempting, points regarding anisometropia. In each case, therefore, to view cases of apparently non- the patient has visual abnormalities associated strabismic disease-free anisometropia in this with their anisometropia. The literature review light. Almeder et. al. were among the early continues in the discussion section of each adopters of the hypothesis that “… most adult case. It emphasizes speculations regarding the anisometropia is the result, rather than the natural course and etiology of the anisometropia cause of amblyopia”.11 Barrett, Bradley, and as a backward look to understand clinical Candy provide a recent extensive review of the findings and treatment outcomes in these cases hypothesis that seemingly pure anisometropia and other cases of pediatric