Interocular Axial Length Difference and Treatment Outcomes of Anisometropic Amblyopia
Purpose: To evaluate the effect of interocular axial length (AL) difference on outcomes of treatment for anisometropic amblyopia in comparison with normal participants.
Methods: In this historical cohort study, 83 patients with anisometropic amblyopia were divided into two age groups, 70 children (mean, 7.86 ± 1.56 and range, 5–15 years) and 13 adults (mean, 26.46 ± 10.87 and range, 16–45 years). The control group consisted of 43 non-amblyopic children and 17 non-amblyopic adults. Treatment outcomes after a period of one year were defined as successful or unsuccessful when posttreatment amblyopic corrected distance visual acuity (CDVA) was reported as ≤0.9 versus CDVA ≤ 0.8, respectively. AL was measured using a Lenstar LS900 (Haag-Streit AG, Switzerland).
Results: Fifty-nine patients showed satisfactory treatment outcomes (55 children and 4 adults), while unsuccessful treatment outcomes were observed in 24 patients (15 children and 9 adults). The mean of amblyopia treatment duration was 1.24 ± 0.76 years. The mean of interocular AL difference in all patients, control, successful and unsuccessful treatment outcome groups were 0.49 ± 0.70mm (range, 0.00–3.89 mm), 0.12 ± 0.07 mm (range, 0.02–0.41), 0.33 ± 0.23 mm (range, 0.00–0.99 mm), and 1.81 ± 0.80 mm (range, 1.14–3.89 mm), respectively. In both age groups, the mean of interocular AL difference in patients with unsuccessful treatment outcomes was greater than those with successful treatment outcomes and that of the control group (P < 0.001).
Conclusion: The results of this study suggest that the outcome of anisometropic amblyopia treatment may depend on the interocular AL difference.
Anisometropic Amblyopia, Axial Length, Refractive Error
1. Aldebasi YH. Prevalence of amblyopia in primary school children in Qassim province, Kingdom of Saudi Arabia. Middle East Afr J Ophthalmol 2015;22:86–91.
2. Khorrami-Nejad M, Akbari MR, Khosravi B. The prevalence of strabismus types in strabismic Iranian patients. Clin Optom 2018;10:19–24.
3. Min FC, Ophthal MS, Thavaratnam LK, Ophthal MS, Shukor IN, Rahmat J, et al. Visual impairment and amblyopia in Malaysian pre-school children-The SEGPAEDS study. Med J Malaysia 2018;73:25–30.
4. Park SH. Current management of childhood amblyopia. Korean J Ophthalmol 2019;33:557–568.
5. Toor SS, Horwood AM, Riddell PM. Anisometropic amblyopia: factors influencing the success or failure of its treatment. Br Ir Orthopt J 2015;2:9–16.
6. Duman R, Atilla H, Çatak E. Characteristics of anisometropic patients with and without strabismus. Turk J Ophthalmol 2018;48:23–26.
7. Roberts CJ, Adams GG. Contact lenses in the management of high anisometropic amblyopia. Eye 2002;16:577–579.
8. Van Leeuwen R, Eijkemans MJ, Vingerling JR, Hofman A, de Jong PT, Simonsz HJ. Risk of bilateral visual impairment in individuals with amblyopia: the Rotterdam study. Br J Ophthalmol 2007;91:1450–1451.
9. Carlton J, Karnon J, Czoski-Murray C, Smith KJ, Marr J. The clinical effectiveness and cost-effectiveness of screening programmes for amblyopia and strabismus in children up to the age of 4–5 years: a systematic review and economic evaluation. Health Technol Assess 2008;12:194.
10. Tommila V, Tarkkanen A. Incidence of loss of vision in the healthy eye in amblyopia. Br J Ophthalmol 1981;65:575– 577.
11. Lee CE, Lee YC, Lee SY. Factors influencing the prevalence of amblyopia in children with anisometropia. Korean J Ophthalmol 2010;24:225–229.
12. Weakley Jr DR. The association between nonstrabismic anisometropia, amblyopia, and subnormal binocularity. Ophthalmology 2001;108:163–171.
13. Zaka-ur-Rab S. Evaluation of relationship of ocular parameters and depth of anisometropic amblyopia with the degree of anisometropia. Indian J Ophthalmol 2006;54:99–103.
14. Donahue SP. The relationship between anisometropia, patient age, and the development of amblyopia. Trans Am Ophthalmol Soc 2005;103:313–316.
15. Ghasempour M, Khorrami-Nejad M, Akbari MR, Amiri MA. The effect of different amblyopia treatment protocols on axial length of non-amblyopic eyes in anisohyperopic patients. J Curr Ophthalmol 2019;31:201–205.
16. Burtolo C, Ciurlo C, Polizzi A, Lantieri PB, Calabria G. Echobiometric study of ocular growth in patients with amblyopia. J Pediatr Ophthalmol Strabismus 2002;39:209–214.
17. Singh N, Rohatgi J, Kumar V. A prospective study of anterior segment ocular parameters in anisometropia. Korean J Ophthalmol 2017;31:165–171.
18. Caputo R, Frosini R, De Libero C, Campa L, Del Magro EF, Secci J. Factors influencing severity of and recovery from anisometropic amblyopia. Strabismus 2007;15:209–214.
19. Hussein MA, Coats DK, Muthialu A, Cohen E, Paysse EA. Risk factors for treatment failure of anisometropic amblyopia. J AAPOS 2004;8:429–434.
20. Cotter SA, Pediatric Eye Disease Investigator Group. Treatment of anisometropic amblyopia in children with refractive correction. Ophthalmology 2006;113:895–903.
21. Demircan S, Gokce G, Yuvaci I, Atas M, Baskan B, Zararsiz G. The assessment of anterior and posterior ocular structures in hyperopic anisometropic amblyopia. Med Sci Monit 2015;21:1181–1188.
22. Hoshikawa R, Ito M, Yano T, Tsutsui K, Sato T, Shimizu K. Association between ocular dominance and anisometropic hyperopia. Am Orthopt J 2016;66:107–113.
23. Bonaccorsi J, Berardi N, Sale A. Treatment of amblyopia in the adult: insights from a new rodent model of visual perceptual learning. Front Neural Circuit 2014;8:82.
24. Lai XJ, Alexander J, He M, Yang Z, Suttle C. Visual functions and interocular interactions in anisometropic children with and without amblyopia. Invest Ophthalmol Vis Sci 2011;52:6849–6859.
25. Lempert P. The axial length/disc area ratio in anisometropic hyperopic amblyopia: a hypothesis for decreased unilateral vision associated with hyperopic anisometropia. Ophthalmology 2004;111:304–308.
26. Swadlow HA, Waxman SG. Axonal conduction delays. Scholarpedia 2012;7:1451.