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Takigawa R, Sasaki K, Hirota M, Nakagawa M, Sasaki K, Mihashi T, Mizuno Y, Mizota A, Matsuoka K. Evaluation of Aniseikonia in Patients with Successfully Treated Anisometropic Amblyopia Using Spatial Aniseikonia Test. J Clin Med 2023; 12:jcm12113766. [PMID: 37297961 DOI: 10.3390/jcm12113766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/18/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Anisometropic amblyopia is decreased visual acuity in one eye, and treatment consists of wearing complete corrective spectacles. Aniseikonia occurs with complete correction of anisometropia using spectacles. Aniseikonia has been ignored when treating pediatric anisometropic amblyopia because of the prevailing belief that anisometropic symptoms are suppressed by adaptation. However, the conventional direct comparison method for evaluating aniseikonia significantly underestimates the degree of aniseikonia. This study investigated whether the adaptation occurs due to long-term anisometropic amblyopia treatment in patients who have had successful amblyopia treatment using a spatial aniseikonia test with high accuracy and repeatability compared with the conventional direct comparison method. The amount of aniseikonia was not significantly different between the patients with successful amblyopia treatment and individuals with anisometropia without a history of amblyopia. In both groups, the aniseikonia per 1.00 D of anisometropia and the aniseikonia per 1.00 mm of aniso-axial length were comparable. The repeatability of the amount of aniseikonia using the spatial aniseikonia test did not differ significantly between the two groups, indicating a high degree of agreement. These findings suggest that aniseikonia is not adapted to amblyopia treatment and that aniseikonia increases as the difference between spherical equivalent and axial length increases.
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Affiliation(s)
- Ryusei Takigawa
- Division of Orthoptics, Graduate School of Medical Care and Technology, Teikyo University, Itabashi, Tokyo 173-8605, Japan
- Department of Orthoptics, Faculty of Medical Technology, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Kakeru Sasaki
- Department of Orthoptics, Faculty of Medical Technology, Teikyo University, Itabashi, Tokyo 173-8605, Japan
- Department of Ophthalmology, School of Medicine, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Masakazu Hirota
- Department of Orthoptics, Faculty of Medical Technology, Teikyo University, Itabashi, Tokyo 173-8605, Japan
- Department of Ophthalmology, School of Medicine, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Maki Nakagawa
- Department of Ophthalmology, School of Medicine, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Kozue Sasaki
- Department of Ophthalmology, School of Medicine, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Toshifumi Mihashi
- Department of Orthoptics, Faculty of Medical Technology, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Yoshinobu Mizuno
- Department of Ophthalmology, School of Medicine, Teikyo University, Itabashi, Tokyo 173-8605, Japan
| | - Atsushi Mizota
- Department of Ophthalmology, School of Medicine, Teikyo University, Itabashi, Tokyo 173-8605, Japan
- Nishikasai Inouye Eye Hospital, Edogawa-Ku, Tokyo 134-0088, Japan
| | - Kumiko Matsuoka
- Department of Orthoptics, Faculty of Medical Technology, Teikyo University, Itabashi, Tokyo 173-8605, Japan
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South J, Gao T, Calderwood M, Turuwhenua J, Roberts P, Lee A, Collins A, Black J. Measuring aniseikonia and investigating neuroplasticity and image factors in amblyopia (MAGNIFY): study protocol for a randomised clinical trial. Trials 2022; 23:358. [PMID: 35478070 PMCID: PMC9044861 DOI: 10.1186/s13063-022-06159-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/07/2022] [Indexed: 11/26/2022] Open
Abstract
Background Aniseikonia represents a potential barrier to neuroplasticity which may limit visual outcomes in children with anisometropic amblyopia. Full correction of refractive error is the first step in standard amblyopia treatment, which corrects for image focus but neglects image size differences. Methods The MAGNIFY study is a double-masked, randomised clinical trial investigating the effectiveness of aniseikonia correcting lenses in children at first diagnosis of significant anisometropia. We hypothesis that aniseikonia correction lenses will improve image clarity and reduce the retinal size differences producing better visual acuity and stereoacuity improvements after 15 weeks of optical treatment for children with anisometropia. Eligible children will be randomly allocated to the treatment group (aniseikonia-correcting spectacle lenses) or control group (standard spectacle lenses). Visual acuity and binocular functions will be assessed every 5 weeks during the 15-week optical treatment phase according to standard amblyopia treatment protocol. Discussion It is possible that correcting aniseikonia along with anisometropia at first diagnosis will promote binocularity as well as increase spectacle adherence by reducing visual discomfort, improving optical treatment outcomes. This could then reduce the need for additional amblyopia treatment such as patching or atropine, reducing the burden on hospital eye departments and potentially improving visual outcomes for children with amblyopia. Trial registration Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12620000061932. Registered on 24 January 2020. Protocol 15th November 2019, version one. Supplementary Information The online version contains supplementary material available at 10.1186/s13063-022-06159-2.
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Affiliation(s)
- Jayshree South
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand.
| | - Tina Gao
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Melinda Calderwood
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Jason Turuwhenua
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Paul Roberts
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Medlink Innovation Limited, Auckland, New Zealand
| | - Arier Lee
- Section of Epidemiology and Biostatistics, The University of Auckland, Auckland, New Zealand
| | - Andrew Collins
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Joanna Black
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
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Abdelzaher HA, Sidky MK, Awadein A, Hosny M. Aniseikonia and visual functions with optical correction and after refractive surgery in axial anisometropia. Int Ophthalmol 2022; 42:1669-1677. [DOI: 10.1007/s10792-021-02161-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 12/18/2021] [Indexed: 11/29/2022]
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Krarup T, Nisted I, Kjærbo H, Christensen U, Kiilgaard JF, Cour M. Measuring aniseikonia tolerance range for stereoacuity - a tool for the refractive surgeon. Acta Ophthalmol 2021; 99:e43-e53. [PMID: 32558241 PMCID: PMC7891617 DOI: 10.1111/aos.14507] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 12/13/2022]
Abstract
Objective No method exists to measure aniseikonia tolerance in stereoacuity. The brain can compensate for 2%–3% aniseikonia (i.e. 2–3 dioptres of anisometropia) without impairing stereoacuity; however, a substantial proportion of anisometropic patients experience problems caused by disruptions of sensory fusion due to surgically induced aniseikonia. We hypothesized that individual differences in tolerance to aniseikonia exist and sought to develop a method to measure aniseikonia tolerance. Methods A total of 21 eye‐healthy phakic individuals older than 50 years of age and 11 patients awaiting clear lens extraction were included. Patients were tested with best corrected near and distance visual acuity, cover/uncover test, eye dominance test, stereoacuity threshold (TNO test), slit lamp examination and ocular coherence tomography. The stereoacuity threshold was determined with aniseikonia induced by different size lenses ranging from 1% to 9% magnification of both eyes in increments of 1%. The aniseikonia tolerance range (ATR) was defined as the percentage aniseikonia in which the stereoacuity threshold was maintained. Results We examined 32 patients with a median age of 65 (95% CI: 62–66 years), CDVA better than 6/7.5 (0.1 logMAR), and median near visual acuity better than 6/6 (0.0 logMAR). The median stereoacuity threshold was 60 arcsec (maximum 30, minimum 120). We observed large inter‐individual differences in ATR: 6/31 (19%) participants had an ATR of ≤1%, 1/31 (3%) had an ATR of 1‐5%, 7/31 (22%) had an ATR of 5‐10%, and 17/31 (54%) had an ATR of >10%. Conclusion We present a reliable method for measuring the amount of aniseikonia that a person can tolerate without impairing stereopsis. We report large inter‐individual differences in tolerance of aniseikonia.
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Affiliation(s)
- Therese Krarup
- Department of Ophthalmology Rigshospitalet‐Glostrup Glostrup Denmark
| | - Ivan Nisted
- Faculty of Health Institute of Clinical Medicine Aarhus N Denmark
| | | | - Ulrik Christensen
- Department of Ophthalmology Rigshospitalet‐Glostrup Glostrup Denmark
| | | | - Morten Cour
- Department of Ophthalmology Rigshospitalet‐Glostrup Glostrup Denmark
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South J, Gao T, Collins A, Lee A, Turuwhenua J, Black J. Clinical Aniseikonia in Anisometropia and Amblyopia. Br Ir Orthopt J 2020; 16:44-54. [PMID: 34278210 PMCID: PMC8269785 DOI: 10.22599/bioj.154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/02/2020] [Indexed: 11/30/2022] Open
Abstract
Purpose: Clinically, aniseikonia (a perceived difference in shape and image size between the eyes) is often neglected in anisometropic amblyopia due to assumed measurement difficulties. Therefore, we currently lack evidence on whether correction of aniseikonia is beneficial. This study aimed to determine whether subjective aniseikonia is measurable in anisometropia with or without amblyopia. Methods: Participants (15–52 years) with Anisometropic Amblyopia (n = 7), Anisometropia without amblyopia (n = 6) and Isometropic Controls (n = 6) were recruited. Subjective aniseikonia was measured using three clinical techniques: Robertson Technique (RT) (penlight and Maddox rod), Aniseikonia Inspector Version 3 (AI3), and the New Aniseikonia Test booklet (NAT), and a psychophysical adaptive method, the Contrast-balanced Aniseikonia Test (CAT), where dichoptic contrast adjustments compensate for any suppression. Results: Eighteen participants completed all tests, one Anisometropic Amblyopia participant could only complete the CAT and NAT due to fusion loss. The Anisometropic Amblyopia group exhibited the most aniseikonia (range –1.50–+10.50%) followed by Anisometropic Controls (range –3.30–+4.50%) and Isometropic Controls (range –1.50–+3.28%). There was a significant trend of more subjective aniseikonia with increasing amounts of anisometropia across all four tests (AI3 r = 0.630, p = 0.005; NAT r = 0.542, p = 0.017; RT r = 0.499, p = 0.035; CAT r = 0.440, p = 0.059. Bland Altman analysis demonstrated clinically significant levels of variability between the tests. Conclusions: Subjective aniseikonia can be reliably measured in patients with anisometropia and suppression. Subjective aniseikonia measurement is recommended as four of the most commonly used clinical tests did not support the 1% per dioptre rule of thumb.
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South J, Gao T, Collins A, Turuwhenua J, Robertson K, Black J. Aniseikonia and anisometropia: implications for suppression and amblyopia. Clin Exp Optom 2019; 102:556-565. [PMID: 30791133 DOI: 10.1111/cxo.12881] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 12/20/2018] [Accepted: 01/13/2019] [Indexed: 11/28/2022] Open
Abstract
Aniseikonia is a difference in the perceived size or shape of images between eyes, and can arise from a variety of physiological, neurological, retinal, and optical causes. Aniseikonia is associated with anisometropia, as both anisometropia itself and the optical correction for anisometropia can cause aniseikonia. Image size differences above one to three per cent can be clinically symptomatic. Common symptoms include asthenopia, headache and diplopia in vertical gaze. Size differences of three and more impair binocular visual functions such as binocular summation and stereopsis. Above five per cent of aniseikonia, binocular inhibition or suppression tend to occur to prevent diplopia and confusion. Aniseikonia can be measured using a range of techniques and can be corrected or reduced by prescribing contact lenses or specially designed spectacle lenses. Subjective testing of aniseikonia is the only way to accurately measure the overall perceived amount of aniseikonia. However, currently it is not routinely assessed in most clinical settings. At least two-thirds of patients with amblyopia have anisometropia, thus we may expect aniseikonia to be common in patients with anisometropic amblyopia. However, aniseikonia may not be experienced by the patient under normal binocular viewing conditions if the image from the amblyopic eye is of poor quality or is too strongly suppressed for image size differences to be recognised. This lack of binocular simultaneous perception in amblyopia may also prevent the measurement of aniseikonia, as most common techniques require direct comparisons of images seen by each eye. Current guidelines for the treatment of amblyopia advocate full correction of anisometropia to equalise image clarity, but do not address aniseikonia. Significant image size differences between eyes may lead to suppression and abnormal binocular adaptations. It is possible that correcting anisometropia and aniseikonia simultaneously, particularly at the initial diagnosis of anisometropia, would reduce the need to develop suppression and improve treatment outcomes for anisometropic amblyopia.
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Affiliation(s)
- Jayshree South
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Tina Gao
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Andrew Collins
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Jason Turuwhenua
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Kenneth Robertson
- School of Optometry, University of Waterloo, Waterloo, Ontario, Canada
| | - Joanna Black
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
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García-Pérez MA, Peli E. Aniseikonia Tests: The Role of Viewing Mode, Response Bias, and Size-Color Illusions. Transl Vis Sci Technol 2015; 4:9. [PMID: 26101722 DOI: 10.1167/tvst.4.3.9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 04/23/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify the factors responsible for the poor validity of the most common aniseikonia tests, which involve size comparisons of red-green stimuli presented haploscopically. METHODS Aniseikonia was induced by afocal size lenses placed before one eye. Observers compared the sizes of semicircles presented haploscopically via color filters. The main factor under study was viewing mode (free viewing versus short presentations under central fixation). To eliminate response bias, a three-response format allowed observers to respond if the left, the right, or neither semicircle appeared larger than the other. To control decisional (criterion) bias, measurements were taken with the lens-magnified stimulus placed on the left and on the right. To control for size-color illusions, measurements were made with color filters in both arrangements before the eyes and under binocular vision (without color filters). RESULTS Free viewing resulted in a systematic underestimation of lens-induced aniseikonia that was absent with short presentations. Significant size-color illusions and decisional biases were found that would be mistaken for aniseikonia unless appropriate action is taken. CONCLUSIONS To improve their validity, aniseikonia tests should use short presentations and include control conditions to prevent contamination from decisional/response biases. If anaglyphs are used, presence of size-color illusions must be checked for. TRANSLATIONAL RELEVANCE We identified optimal conditions for administration of aniseikonia tests and appropriate action for differential diagnosis of aniseikonia in the presence of response biases or size-color illusions. Our study has clinical implications for aniseikonia management.
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Affiliation(s)
- Miguel A García-Pérez
- Departamento de Metodología, Facultad de Psicología, Universidad Complutense, Campus de Somosaguas, Madrid, Spain
| | - Eli Peli
- The Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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