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Ma MML, Scheiman M. Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 1: prevalence, classification, risk factors, natural history and clinical characteristics. Strabismus 2023; 31:97-128. [PMID: 37489263 DOI: 10.1080/09273972.2023.2227681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
INTRODUCTION Intermittent exotropia (IXT) is a common form of strabismus. It is an outward deviation of one eye typically when viewing at distance. Symptoms include, but are not limited to double vision, eyes feeling tired, excessive blinking, and reduced quality of life. Its clinical characteristics are distinctive from other types of strabismus. This paper provides a comprehensive review of prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. METHODS Search strategies involving combination of keywords including intermittent exotropia, exotropia, divergences excess, basic exotropia, prevalence, incidence, classification, terminology, risk factor, natural history, observation, angle of deviation, control, control score, symptom, quality of life, suppression, anomalous retinal correspondence, AC/A, accommodative convergence/accommodation, accommodative convergence, convergence, accommodation, vergence, incomitance and vertical were used in Medline. All English articles from 1900/01/01 to 2020/09/01 were reviewed. The reference list of the identified article was also checked for additional relevant article. Studies focused on animal model or strabismus associated with neurologic disorder or injury were excluded. RESULTS The estimated prevalence of IXT in children ranges from 0.1% to 3.7%. Hypoxia at birth and being female are potential risk factors of IXT. Using validated measures of control, multicenter prospective studies showed that the rate of conversion from IXT to constant exotropia is low. The angle of deviation is the most reported outcome measure in studies of IXT. It is often used to represent the severity of the condition and has been suggested as one of the four core outcomes for studies of the surgical management of IXT. Control of exodeviation is one of the four suggested core outcomes for study of surgery of IXT and is considered the main parameter of disease severity. Several validated tools for quality of life score are available to evaluate the subjective severity of IXT. DISCUSSION We reviewed the prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. Further research into these areas, especially its clinical characteristics (e.g. suppression, dual retinal correspondence), will increase our understanding of this condition and potentially lead to better management of this common form of strabismus.
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Affiliation(s)
- Martin Ming-Leung Ma
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou
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Jeon H, Choi HY. Long-term surgical outcomes of basic-type exotropia in patients with hyperopia. BMC Ophthalmol 2023; 23:187. [PMID: 37106358 PMCID: PMC10134509 DOI: 10.1186/s12886-023-02909-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 04/05/2023] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND To investigate the surgical outcomes of basic-type exotropia in patients with hyperopia. METHODS The medical records of patients who underwent surgery for basic-type exotropia and had been followed up for ≥ 2 years were retrospectively recruited. Patients with myopia and spherical equivalent (SE) < -1.0 diopters (D) were excluded. The patients were classified according to the SE: group H had a SE ≥ + 1.0 D, and group E had -1.0 ≤ SE < + 1.0 D. The surgical success rate and sensory outcome were compared. Surgical success was defined as exodeviation ≤ 10 prism diopters (PD) and esodeviation ≤ 5 PD at 6 m fixation. Stereoacuity was measured using the Titmus Preschool Stereoacuity Test. RESULTS Seventy-five patients (24 males and 51 females, mean age 5.1 ± 2.6 years, range 2.7-14.8) were included. The SE ranged from -0.9 to 4.4 and 21 patients were classified into group H and 54 into group E. The success rates were higher in group H than in group E during the entire follow-up period, but the differences were significant only at the final examination. At the final follow-up, 11 of the 21 (52.4%) patients in group H and 15 of the 54 (27.7%) in group E maintained successful alignment, whereas 10 (47.6%) and 38 (70.4%) patients exhibited recurrence. Overcorrection was exhibited in one (1.9%) patient in group E. Sensory results were comparable between the groups. The follow-up period did not differ between the two groups. The survival analysis showed no difference in the surgical results between the two groups. CONCLUSIONS Surgery for basic-type intermittent exotropia resulted in superior outcomes in patients with hyperopia compared to those with emmetropia.
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Affiliation(s)
- Hyeshin Jeon
- Department of Ophthalmology, School of Medicine, Pusan National University, Busan, South Korea
- Department of Ophthalmology and Medical Research Institute, Pusan National University Hospital, 1-10 Ami-Dong Seo-Gu, Busan, 47732, South Korea
| | - Hee-Young Choi
- Department of Ophthalmology, School of Medicine, Pusan National University, Busan, South Korea.
- Department of Ophthalmology and Medical Research Institute, Pusan National University Hospital, 1-10 Ami-Dong Seo-Gu, Busan, 47732, South Korea.
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Ucar F, Savas C, Ture H. Results of Unilateral Lateral Rectus Recession Surgery in 15 - 30 PD Intermittent Exotropia. Klin Monbl Augenheilkd 2023. [PMID: 37015253 DOI: 10.1055/a-2009-0564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
PURPOSE To evaluate the surgical outcomes of unilateral lateral rectus muscle recession (ULR) with low surgical dosage in patients with intermittent exotropia (IXT) of 15 - 30 prism dioptres (PD). METHODS We retrospectively analysed 92 eyes of 92 patients who underwent ULR surgery with the diagnosis of IXT of 15 - 30 PD at distance fixation between January 2017 and June 2019. ULR surgery of 6.5 mm was performed for exotropia of 15 - 20 PD, 7.5 mm for that of 20 - 25 PD, and 8.5 mm for that of 25 - 30 PD and postoperative results were evaluated at the 1st week, 1st month, 6th month, and the 2nd year. Orthophoria or IXT less than 10 PD was accepted as successful. RESULTS The mean preoperative deviation angle at distance was 22.3 ± 4.4 PD. Mean postoperative deviation angles at distance were 2.5 ± 1.7, 3.9 ± 2.4, 6.5 ± 3.0, and 8.7 ± 3.1 at 1 week, 1 month, 6 months, and 2 years, respectively. The surgical success rate of ULR was 100, 96.7, 84.7, and 77.1% at the 1st week, 1st month, 6th month, and the 2nd year, respectively. In the long-term results, there were no complications such as lateral gaze incomitance, overcorrection, or deterioration in stereopsis. CONCLUSION Using the ULR technique, we were able to obtain effective surgical results in IXT with less surgical dosage and without any serious complications. ULR surgery can be used as an effective method in patients with IXT of 15 - 30 PD.
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Affiliation(s)
- Fikret Ucar
- Ophthalmology, Private Konyagoz Hospital, Konya, Turkey
| | - Cemil Savas
- Ophthalmology, Private Konyagoz Hospital, Konya, Turkey
| | - Huseyin Ture
- Ophthalmology, Karaman Selcuklu Hospital, Karaman, Turkey
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Anand K, Krishnan A, Kumar P, Bharadwaj A, Dutta P, Rastogi A, Hariani A. Comparative Study of Bilateral Versus Unilateral Strabismus Surgery in the Management of Lateral Incomitance in Intermittent Exotropia. J Pediatr Ophthalmol Strabismus 2022:1-5. [PMID: 36102267 DOI: 10.3928/01913913-20220810-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate and compare bilateral asymmetric lateral rectus recession versus unilateral resection-recession surgery in the management of lateral incomitance in intermittent exotropia. METHODS A prospective randomized interventional comparative study was conducted consisting of 80 patients with intermittent exotropia (older than 7 years) having significant lateral incomitance. They were equally divided into two groups by a sealed envelope system. The bilateral group underwent bilateral asymmetric lateral rectus recession and the unilateral group underwent unilateral lateral rectus recession and medial rectus resection based on post-patch deviation. Parameters assessed were change in horizontal deviation, change in lateral incomitance, binocularity, motility limitation, and complications, if any. Surgical outcome was considered successful if the primary deviation was within ±8 prism diopters (PD) and lateral incomitance was less than 5 PD. RESULTS The mean lateral incomitance preoperatively and postoperatively was 8.3 ± 1.6 and 2.8 ± 2.4 PD in the bilateral group and 8.9 ± 1.4 and 3.7 ± 2.5 PD in the unilateral group, respectively. There was no statistically significant difference in the postoperative lateral incomitance between the two groups (P = .25), but a statistically significant difference was observed between preoperative and postoperative lateral incomitance in each group (P < .0001). CONCLUSIONS Both procedures are equally efficacious in achieving acceptable ocular alignment and improving significant lateral incomitance in patients with intermittent exotropia with deviations between 15 and 35 PD without causing significant motility limitation. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].
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Ismail AA, Abdelkader MF, Mohamed AA, Abdelaziz ST. Evaluation of Efficacy and Lateral Gaze Incomitance in Symmetrical and Asymmetrical Surgery for Concomitant Esotropia and Exotropia. Clin Ophthalmol 2021; 15:3613-3621. [PMID: 34471346 PMCID: PMC8405227 DOI: 10.2147/opth.s326659] [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: 06/30/2021] [Accepted: 08/13/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose Evaluation of asymmetrical and symmetrical horizontal strabismus surgery as regards efficacy and postoperative lateral gaze incomitance. Patients and Methods This prospective comparative interventional case series study included 40 patients of age more than 3 years with alternating horizontal strabismus. Patients were divided according to the type of horizontal deviation into esotropia and exotropia groups, which were further subdivided into asymmetrical and symmetrical subgroups in each type. The surgery was defined as symmetrical procedure if the surgery was done on the same muscle in the two eyes and it was defined as asymmetric in recess-resect procedures in one eye, and three horizontal muscles surgery. Preoperative and postoperative measurements were done in primary position, right, and left gaze using alternate prism cover test and hand-held orthopedic goniometer. Results At the end of follow-up period, a statistically insignificant difference (P value = 0.8057) was present in the success rate between the asymmetrical and symmetrical subgroups of esotropia (90 and 86.67%, respectively) and it was 100% in both exotropia subgroups. Lateral gaze incomitance results were different between esotropia and exotropia subgroups. In esotropia, a statistically significant difference was reported at 1 month (0.009), which became insignificant at 6 months (0.077) and 12 months (0.077) between asymmetrical and symmetrical subgroups. In exotropia subgroups, there was a statistically insignificant difference in lateral gaze incomitance at 1, 6, and 12 months (P = 1). Conclusion Asymmetrical procedure had the same efficacy and success rate of symmetrical procedure for the correction of concomitant horizontal deviations in primary gaze without persistent postoperative lateral gaze incomitance, especially in exotropia. Clinical Trial Registration NCT04199286.
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Affiliation(s)
| | | | - Asmaa Anwar Mohamed
- Ophthalmology Department, Faculty of Medicine, Minia University, Minia, Egypt
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Moon Y, Shin SH, Lee JY, Lee WJ, Kim YJ, Yang JJ, Lee SJ, Lim HW. Quantitative Analysis of Eyeball Rotation During Lateral Gaze in Intermittent Exotropia: A Magnetic Resonance Imaging Study. Transl Vis Sci Technol 2021; 10:20. [PMID: 34570191 PMCID: PMC8479570 DOI: 10.1167/tvst.10.11.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the eyeball rotation during lateral gaze in patients with intermittent exotropia (IXT) using three-dimensional magnetic resonance imaging (MRI). Methods In this prospective observational study, patients with IXT (n = 29) underwent orbital MRI during central, right, and left gazes. Fixation targets were placed at a 40° angle for lateral gaze. After acquisition of MR images, the position of the static tissues other than the eyeball in the MR images were matched three-dimensionally. The optical axis was defined as the perpendicular line to its lens passing through the corneal vertex. The rotation angle was measured as the angle between optical axes in central gaze and lateral gaze using ImageJ. A difference of 3° or more in the rotational angle between both eyes was considered a significant difference. Results Eight patients (26.7%) had a larger adduction angle than the abduction angle of the fellow eye and six patients (20.0%) showed a smaller adduction angle during lateral gaze on at least one side. There was no significant factor associated with the pattern of rotation. Conclusions Almost one-half of the patients with IXT had significant difference in the rotation angle between both eyes during lateral gaze. Measurement of the rotation angle during lateral gaze using MRI showed that IXT is not a perfectly comitant disturbance of gaze in some subjects. Translational Relevance Quantitative analysis for eye movements using MRI can provide useful information for physiologic mechanism and proper surgical planning in patients with IXT.
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Affiliation(s)
- Yeji Moon
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, Korea
| | - Seung Hak Shin
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea
| | - Ji Young Lee
- Hanyang Vision Research Center, Hanyang University, Seoul, Korea.,Department of Radiology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea
| | - Won June Lee
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, Korea
| | - Yu Jeong Kim
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, Korea
| | - Jin-Ju Yang
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, Korea
| | - Su-Jae Lee
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Korea
| | - Han Woong Lim
- Department of Ophthalmology, Hanyang University Hospital, Hanyang University College of Medicine, Seoul, Korea.,Hanyang Vision Research Center, Hanyang University, Seoul, Korea
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Chougule P, Jain M, Sachdeva V, Kekunnaya R. Consecutive Esotropia with and without Abduction Limitation - Risk Factors and Surgical Outcomes of Lateral Rectus Advancement. J Binocul Vis Ocul Motil 2021; 71:62-70. [PMID: 33783332 DOI: 10.1080/2576117x.2021.1880311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
Purpose: To identify risk factors for abduction limitation in consecutive esotropia following surgical correction of exotropia. To study outcomes of lateral rectus advancement for consecutive esotropia correction.Methods: Patients with consecutive esotropia (>10PD) operated between 2007 and 2019 with a minimum follow-up of 2 months were reviewed retrospectively. Preoperative and postoperative alignment and ocular motility were recorded. Patients were classified into those with full abduction (group-A) and with abduction limitation (group-B). Success was defined as deviation ≤10 PD of esotropia or exotropia in the primary position.Results: Forty-cases fulfilled the inclusion criteria (group-A = 28 and group-B = 12). Median age at surgery was five years, median consecutive esotropia was 20PD and follow-up was 29.18 months. Abduction limitation (group-B) was associated with constant exotropia (p = .01) and larger bilateral lateral rectus recession (group-A = 13 mm, group-B = 15 mm; p = .04). Nineteen patients underwent lateral rectus advancement (group-A = 12, group-B = 7), one underwent medial-rectus recession and two were excluded due to lack of postoperative follow-up. Five patients had spontaneous resolution with good alignment (group-A = 3, group-B = 2), two refused surgery, three were observed and eight were lost to follow-up. Success following second surgery was similar in both groups (group-A = 86%, group-B = 77%)(p = 1).Conclusion: Constant exotropia and larger lateral rectus recession were associated with abduction limitation in consecutive esotropia. Lateral rectus advancement produced good outcomes irrespective of abduction limitation.
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Affiliation(s)
- Pratik Chougule
- The David Brown Children's Eye Care Center, Child Sight Institute, L V Prasad Eye Institute, Vijayawada, India
| | - Mayank Jain
- Jasti V Ramanamma Children's Eye Care Centre, Child Sight Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Virender Sachdeva
- Nimmagadda Prasad Children's Eye Care Centre, Child Sight Institute, L. V. Prasad Eye Institute, Visakhapatnam, India
| | - Ramesh Kekunnaya
- Jasti V Ramanamma Children's Eye Care Centre, Child Sight Institute, L V Prasad Eye Institute, Hyderabad, India
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Chougule P, Kekunnaya R. Surgical management of intermittent exotropia: do we have an answer for all? BMJ Open Ophthalmol 2019; 4:e000243. [PMID: 30997406 PMCID: PMC6440598 DOI: 10.1136/bmjophth-2018-000243] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 12/20/2018] [Accepted: 12/28/2018] [Indexed: 12/11/2022] Open
Abstract
Intermittent exotropia (X(T)) is one of the most common form of strabismus with surgery being the mainstay of treatment. The main goal of surgery is to preserve binocular vision and stereopsis and to prevent its further loss. The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance and quality of life. Bilateral lateral rectus muscle recession and unilateral lateral rectus recession with medial rectus resection, are the two most common surgical procedures performed and have been studied extensively in basic, divergence excess and convergence insufficiency types of X(T). However, there is no consensus over the relative efficacy of the two procedures in terms of postoperative alignment, residual or recurrent exotropia and consecutive esotropia with widely variable results, which can be attributed to poor understanding of the natural course of the disease. Multiple demographic, clinical and anatomic features that may influence the surgical outcomes have been studied to explain this variability. Moreover, most of the evidence regarding surgical outcomes of X(T) is from retrospective studies and the ongoing randomised prospective trials can shed light on long-term efficacy of these procedures. The goal of this review is to give a comprehensive overview of the outcomes of various surgical techniques in the management of different types of X(T), the preoperative and postoperative factors that may affect the surgical outcomes and to discuss the dilemmas faced by the treating surgeons including the effective management of overcorrection and undercorrection.
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Affiliation(s)
- Pratik Chougule
- Child Sight Institute, Jasti V Ramanamma Children's Eye Care Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Ramesh Kekunnaya
- Child Sight Institute, Jasti V Ramanamma Children's Eye Care Centre, L V Prasad Eye Institute, Hyderabad, India
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Jung EH, Yu YS, Kim SJ. A comparison of surgical outcomes between pre-and full-term patients with exotropia. PLoS One 2018; 13:e0208848. [PMID: 30532279 PMCID: PMC6286133 DOI: 10.1371/journal.pone.0208848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/24/2018] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To compare the surgical outcomes between pre- and full-term patients with exotropia and to examine the factors associated with surgical outcomes. METHODS This retrospective study included 48 pre- and 432 full-term patients with basic-type exotropia who underwent unilateral or bilateral lateral rectus muscle (ULR or BLR) recession. Preoperative characteristics and surgical outcomes were compared between the pre- and full-term infants. Additionally, factors affecting the surgical outcomes were evaluated in all patients. RESULTS The preoperative characteristics were significantly different between the pre- and full-term groups in terms of neurodevelopmental disabilities (p = 0.020). There were no significant differences between the pre- and full-term groups in terms of the success, overcorrection, and recurrence rates after the mean follow-up period of 34.6 ± 13.9 months (p = 0.697). The major cause of surgical failure was recurrence in both groups. Pre-term birth was not a risk factor for overcorrection and recurrence. However, regardless of the pre- or full-term birth status, the presence of neurodevelopmental disabilities significantly affected final overcorrection (p = 0.004). CONCLUSIONS Pre-term patients with exotropia showed similar surgical outcomes to full-term controls. The presence of neurodevelopmental disabilities was a risk factor for final overcorrection.
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Affiliation(s)
- Eun Hye Jung
- Department of Ophthalmology, Chuncheon Sacred Heart Hospital, Chuncheon, Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
| | - Young Suk Yu
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
| | - Seong-Joon Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
- * E-mail:
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Adams DL, Economides JR, Horton JC. Incomitance and Eye Dominance in Intermittent Exotropia. Invest Ophthalmol Vis Sci 2017; 58:4049-4055. [PMID: 28813578 PMCID: PMC5559177 DOI: 10.1167/iovs.17-22155] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine if the deviation angle changes in subjects with intermittent exotropia as they alternate fixation between the right and left eye in primary gaze. Methods In this prospective observational cohort study, 37 subjects with intermittent exotropia were tested for evidence of incomitance. The position of each eye was recorded with a video tracker during fixation on a small central target. A cover-uncover test was performed by occluding one eye with a shutter that passed infrared light, allowing continuous tracking of both eyes. The deviation angle was measured during periods of right eye and left eye fixation. Incomitance was assessed as a function of eye preference, fixation stability, and exotropia variability. Results The mean exotropia was 18.2° ± 8.1°. A difference between right exotropia and left exotropia was detectable in 16/37 subjects. Allowing for potential tracking error, the incomitance had a mean amplitude of 1.7°. It was not related to a difference in accommodative effort, eye preference, fixation stability, or variability in deviation. Conclusions Comitance is regarded as a feature that distinguishes strabismus from paralytic or restrictive processes. Unexpectedly, eye tracking during the cover-uncover test showed that incomitance is present in approximately 40% of subjects with intermittent exotropia. It averages 10% of the exotropia, and can equal up to 5°. When substantial, it may be worth considering when planning surgical correction.
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Affiliation(s)
- Daniel L Adams
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States.,Center for Mind/Brain Sciences, The University of Trento, Trento, Italy
| | - John R Economides
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Jonathan C Horton
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
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