Mental Health Conditions Associated With Strabismus in a Diverse Cohort of US Adults

Importance

Greater understanding of the association between strabismus and mental health conditions across sociodemographic backgrounds may inform strategies to improve mental well-being in this population.

Objective

To describe the association of strabismus with mental health conditions in a diverse cohort of US adults.

Design, Setting, and Participants

This cross-sectional study used data from the National Institutes of Health's All of Us Research Program, an ongoing program launched in 2015. The study included 3646 adults (aged ≥18 years) with strabismus and 3646 propensity score-matched controls. Statistical analysis was conducted from September 12, 2023, to January 29, 2024.

Main Outcomes and Measures

Adults with strabismus were propensity score matched on age, gender, race and ethnicity, income, educational level, and insurance status in a 1:1 ratio with adults without strabismus. The prevalences of anxiety, depression, substance use and addiction, bipolar disorder, and schizophrenia spectrum disorder among adults with strabismus were compared with controls. Logistic regression was used to evaluate the association of mental health conditions with sociodemographic factors in each group.

Results

This study included 3646 adults with strabismus (median age, 67 years [IQR, 53-76 years]; 2017 women [55%]) and 3646 propensity score-matched controls (median age, 67 years [IQR, 53-76 years]; 2017 women [55%]). Individuals with strabismus had higher prevalences of anxiety (1153 [32%] vs 519 [14%]; difference, 17%; 95% CI, 15%-19%; P < .001), depression (1189 [33%] vs 514 [14%]; difference, 19%; 95% CI, 17%-20%; P < .001), substance use and addiction (116 [3%] vs 51 [1%]; difference, 2%; 95% CI, 1%-3%; P < .001), bipolar disorder (253 [7%] vs 101 [3%]; difference, 4%; 95% CI, 3%-5%; P < .001), and schizophrenia spectrum disorder (103 [3%] vs 36 [1%]; difference, 2%; 95% CI, 1%-3%; P < .001) compared with individuals without strabismus. Among adults with strabismus, higher odds of mental health conditions were associated with younger age (odds ratio [OR], 1.11 per 10-year decrease; 95% CI, 1.06-1.16 per 10-year decrease), female gender (OR, 1.62; 95% CI, 1.41-1.85), Black or African American race and ethnicity (OR, 1.22; 95% CI, 1.01-1.48), low income (OR, 3.06; 95% CI, 2.56-3.67), and high school education or less (OR, 1.58; 95% CI, 1.34-1.85).

Conclusions and Relevance

In a diverse and nationwide cohort, adults with strabismus were more likely to have mental health conditions compared with adults without strabismus. Further investigation into the risk factors for poor mental health among adults with strabismus across sociodemographic backgrounds may offer novel opportunities for interventions to improve mental well-being in this population.

Impact of Vision Impairment and Ocular Morbidity and Their Treatment on Quality of Life in Children: A Systematic Review

TOPIC

This review summarizes existing evidence of the impact of vision impairment and ocular morbidity and their treatment on children's quality of life (QoL).

CLINICAL RELEVANCE

Myopia and strabismus are associated with reduced QoL among children. Surgical treatment of strabismus significantly improves affected children's QoL.

METHODS

We conducted a systematic review and meta-analysis by screening articles in any language in 9 databases published from inception through August 22, 2022, addressing the impact of vision impairment, ocular morbidity, and their treatment on QoL in children. We reported pooled standardized mean differences (SMDs) using random-effects meta-analysis models. Quality appraisal was performed using Joanna Briggs Institute and National Institutes of Health tools. This study was registered with the International Prospective Register of Systematic Reviews (identifier, CRD42021233323).

RESULTS

Our search identified 29 118 articles, 44 studies (0.15%) of which were included for analysis that included 32 318 participants from 14 countries between 2005 and 2022. Seventeen observational and 4 interventional studies concerned vision impairment, whereas 10 observational and 13 interventional studies described strabismus and other ocular morbidities. Twenty-one studies were included in the meta-analysis. The QoL scores did not differ between children with and without vision impairment (SMD, -1.04; 95% confidence interval [CI], -2.11 to 0.03; P = 0.06; 9 studies). Myopic children demonstrated significantly lower QoL scores than those with normal vision (SMD, -0.60; 95% CI, -1.09 to -0.11; P = 0.02; 7 studies). Children with strabismus showed a significantly lower QoL score compared with those without (SMD, -1.19; 95% CI, -1.66 to -0.73; P < 0.001; 7 studies). Strabismus surgery significantly improved QoL in children (SMD, 1.36; 95% CI, 0.48-2.23; P < 0.001; 7 studies). No randomized controlled trials (RCTs) concerning refractive error and QoL were identified. Among all included studies, 35 (79.5%) were scored as low to moderate quality; the remaining met all quality appraisal tools criteria.

DISCUSSION

Reduced QoL was identified in children with myopia and strabismus. Surgical correction of strabismus improves the QoL of affected children, which supports insurance coverage of strabismus surgery. Further studies, especially RCTs, investigating the impact of correction of myopia on QoL are needed.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Associations of Eye-Related Quality of Life With Vision, Visuomotor Function, and Self-Perception in Children With Strabismus and Anisometropia

Purpose

To evaluate associations between eye-related quality of life (ER-QOL) assessed by the Child Pediatric Eye Questionnaire (Child PedEyeQ) and functional measures (vision, visuomotor function, self-perception) in children with strabismus, anisometropia, or both. Our hypothesis was that children with functional deficits would have lower ER-QOL, and if so, these associations would support the convergent construct validity of the Child PedEyeQ.

Methods

We evaluated 114 children (ages 5-11 years) with strabismus, anisometropia, or both. Each child completed the Child PedEyeQ to assess four Rasch-scored domains of ER-QOL: Functional Vision, Bothered by Eyes/Vision, Social, and Frustration/Worry. In addition, children completed one or more functional tests: visual acuity (n = 114), Randot Preschool Stereoacuity (n = 92), contrast balance index (suppression; n = 91), Readalyzer reading (n = 44), vergence instability (n = 50), Movement Assessment Battery for Children-2 manual dexterity (n = 57), and Pictorial Scale of Perceived Competence and Social Acceptance for Young Children (n = 44).

Results

Child PedEyeQ Functional Vision domain scores were correlated with self-perception of physical competence (rs = 0.65; 95% confidence interval [CI], 0.35-0.96) and reading speed (rs = 0.47; 95% CI, 0.16-0.77). Bothered by Eyes/Vision domain scores were correlated with self-perception of physical competence (rs = 0.52; 95% CI, 0.21-0.83). Moderate correlations were observed between Social domain scores and vergence instability (rs = -0.46; 95% CI, -0.76 to -0.15) and self-perception of physical competence (rs = 0.43; 95% CI, 0.12-0.73) and peer acceptance (rs = 0.49; 95% CI, 0.18-0.80). Frustration/Worry domain scores were moderately correlated with self-perception of physical competence (rs = 0.41; 95% CI, 0.10-0.71) and peer acceptance (rs = 0.47; 95% CI, 0.16-0.77).

Conclusions

Strong and moderate correlations were observed between functional measures and Child PedEyeQ domain scores. These associations provide supporting evidence that the Child PedEyeQ has convergent construct validity.

Patient-derived questionnaire items for patient-reported outcome measures in adults with strabismus

In a previous study we performed individual interviews of adults with strabismus and identified specific health-related quality of life concerns. In this present report we provide the entire list of specific questionnaire items that were created, one for each concern articulated in the interviews. Our aim in reporting this full list of 181 individual, patient-derived questionnaire items is to provide a resource to clinicians and researchers interested in developing patient-reported outcome measures for adults with strabismus.

Psychosocial interventions for improving quality of life outcomes in adults undergoing strabismus surgery

BACKGROUND

Strabismus, also known as squint, can have a debilitating effect on a person's self-esteem, quality of life and mood, as well as increase their feelings of social anxiety and avoidance behaviour. Strabismus surgery can improve both the alignment of a person's eyes and, in appropriate cases, relieve symptoms such as double vision. However, evidence indicates that not all patients experience a meaningful improvement in their quality of life postsurgery. Pre-surgical psychosocial interventions have been found to improve patient reported outcomes in other long-term conditions.

OBJECTIVES

To assess the effects of psychosocial interventions versus no intervention on quality of life and psychosocial outcomes in adults undergoing strabismus surgery.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision group Trials Register) (2016, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to February 2016), EMBASE (January 1980 to February 2016), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to February 2016), PsycINFO (January 1967 to February 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 February 2016.We also manually searched the British Orthoptic Journal, proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA) and published transactions from the meetings of European Strabismus Association (ESA) and American Association for Pediatric Ophthalmology and Strabismus (AAPOS). These were searched from 1980 to present. We also carried out handsearches of Psychology and Health, British Journal of Health Psychology, Health Psychology and Annals of Behavioral Medicine.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs), including cluster-RCTs, in which effectiveness of a psychosocial intervention had been evaluated in patients due to undergo strabismus surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the search results for eligibility.

MAIN RESULTS

None of the 88 studies we identified met the inclusion criteria of this Cochrane review.

AUTHORS' CONCLUSIONS

We found no evidence that evaluated the impact of psychosocial interventions on patients undergoing squint surgery. We believe future research should focus on developing and evaluating the use of targeted psychosocial interventions to improve a patient's quality of life after strabismus surgery.

drawMD APP-aided preoperative anesthesia education reduce parents anxiety and improve satisfaction

OBJECTIVE

There is no existing standard format for preoperative anesthesia education. The drawMD APP is an visible preoperative education tool. The aim of this study was to evaluate the effects of drawMD APP on pre-operative anesthesia education.

METHODS

The parents were randomized to receive drawMD APP-aided pre-operative anesthesia education or standard verbal education. Parental anxiety was measured before education (T0) and immediately after education (T1), and after operation (T4). Children's anxiety was assessed before education (T0) and at the operation room (T2). Children's emergence behavior and Parents' satisfaction were assessed after operation (T4).

RESULTS

The parents' anxiety levels at T1 and T4 were significantly lower than that of the control. The satisfaction scores in the drawMD group were significantly higher than that in the control group. There were no differences in children's anxiety and the incidence of emergence delirium between the two groups.

CONCLUSIONS

The drawMD APP-aided pre-operative education is effective in the reduction of parental pre-operative anxiety and in improvement of parents' satisfaction, but has no influence on children.

PRACTICE IMPLICATIONS

Anesthesiologists can consider using drawMD APP to conduct pre-operative education in parents whose children are scheduled for surgery.

Rasch Analysis of the Adult Strabismus Quality of Life Questionnaire (AS-20) among Chinese Adult Patients with Strabismus

Background

The impact of strabismus on visual function, self-image, self-esteem, and social interactions decrease health-related quality of life (HRQoL).The purpose of this study was to evaluate and refine the adult strabismus quality of life questionnaire (AS-20) by using Rasch analysis among Chinese adult patients with strabismus.

Methods

We evaluated the fitness of the AS-20 with Rasch model in Chinese population by assessing unidimensionality, infit and outfit, person and item separation index and reliability, response ordering, targeting and differential item functioning (DIF).

Results

The overall AS-20 did not demonstrate unidimensional; however, it was achieved separately in the two Rasch-revised subscales: the psychosocial subscale (11 items) and the function subscale (9 items). The features of good targeting, optimal item infit and outfit, and no notable local dependence were found for each of the subscales. The rating scale was appropriate for the psychosocial subscale but a reduction to four response categories was required for the function subscale. No significant DIF were revealed for any demographic and clinical factors (e.g., age, gender, and strabismus types).

Conclusion

The AS-20 was demonstrated by Rasch analysis to be a rigorous instrument for measuring health-related quality of life in Chinese strabismus patents if some revisions were made regarding the subscale construct and response options.

Quality of life in adults with strabismus

PURPOSE

To assess relative quality of life in patients with strabismus.

DESIGN

Retrospective cohort study.

METHODS

The 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) was performed in 42 strabismic adults over the age of 50 years at a single institution. Subscale scores were compared with those of patients with other ocular diseases, including diabetic retinopathy, age-related macular degeneration (AMD), glaucoma, cataract, cytomegalovirus (CMV) retinitis, and low vision.

RESULTS

Median visual acuity was 20/20 (range 20/12.5-20/50), and 34 patients (81%) reported diplopia. Strabismic patients performed the same or worse on nearly all vision-related subscales than did patients with diabetic retinopathy, age-related macular degeneration, glaucoma, cataract, and CMV retinitis. Additionally, strabismic patients reported significantly worse ocular pain than all comparison groups before any surgery was performed.

CONCLUSIONS

Strabismus impacts quality of life through both functional and psychosocial factors. Physicians treating strabismic patients should recognize these quality-of-life issues and address them accordingly.

Effects of corrective surgery on social phobia, psychological distress, disease-related disability and quality of life in adult strabismus patients

BACKGROUND

Corrective surgery is done for ocular alignment and disrupted facial expression in some cases of adult strabismus patients. The effects of corrective surgery on the presence of social phobia (SP) diagnosis, the severity of social anxiety symptoms, the disease-related disability and the quality of life (QoL) among strabismus patients have not been thoroughly studied yet.

METHODS

The study sample was composed of patients who had undergone corrective surgery for strabismus. Preoperative and postoperative evaluations made by using standardised measures of social phobia diagnosis (DSM-IV-TR) and severity (Liebowitz Social Anxiety Scale (LSAS)), anxiety and depression (Hospital Anxiety and Depression Scale (HADS)), disability (Sheehan Disability Scale) and quality of life (short form-36).

RESULTS

Preoperatively, SP diagnosis was detected in 17 of 31 (54.8%) patients, whereas postoperatively 6 of 31 (19.4%) patients had SP (p=0.001). Participants showed a significant decrease in all subscale scores and total score of both LSAS and HADS compared with their preoperative scores. Significant improvements were observed in QoL and disability scores as well.

CONCLUSIONS

Adult strabismus patients seem to gain benefits from corrective surgery not only for their ocular misalignment but also for social anxiety levels that may be associated with improvements in their QoL and disability levels.

[Psychosocial aspects of strabismus]

Binocular vision is characterized by a harmonious relation between sensory and motor systems of both eyes. This relation enables directing visual axes toward the observed object simultaneously, fusing images from two eyes, and the sense of three-dimensionality. Motility and binocular vision disorders occur in manifest and latent strabismus. The irregular position of eyes in strabismus is perceived by most people as an esthetic defect. Also, psychosocial consequences and the importance of treating strabismus are very superficially explained in this context. Bearing in mind the results of recent researches, which indicate that individuals of all ages with strabismus face different difficulties in psychosocial functioning, we believe that this issue in our surroundings should be dealt with. Strabismus leads to forming prejudices which usually have a negative impact on socialization and employment opportunities.Timely treatment of strabismus has a positive influence on the functionality of binocular vision, building self-esteem and self-satisfaction, being accepted by typically developing population, the quality and quantity of social interaction. The aim of this paper is to present the relation between strabismus and psychosocial reactions with regard to the available literature.

Successful treatment of diplopia with prism improves health-related quality of life

PURPOSE

To report change in strabismus-specific health-related quality of life (HRQOL) following treatment with prism.

DESIGN

Retrospective cross-sectional study.

METHODS

Thirty-four patients with diplopia (median age 63, range 14-84 years) completed the Adult Strabismus-20 questionnaire (100-0, best to worst HRQOL) and a diplopia questionnaire in a clinical practice before prism and in prism correction. Before prism, diplopia was "sometimes" or worse for reading and/or straight-ahead distance. Prism treatment success was defined as diplopia rated "never" or "rarely" on the diplopia questionnaire for reading and straight-ahead distance. Failure was defined as worsening or no change in diplopia. For both successes and failures, mean Adult Strabismus-20 scores were compared before prism and in prism correction. Each of the 4 Adult Strabismus-20 domains (self-perception, interactions, reading function, and general function) was analyzed separately.

RESULTS

Twenty-three of 34 (68%) were successes and 11 (32%) were failures. For successes, reading function improved from 57 ± 27 (SD) before prism to 69 ± 27 in-prism correction (difference 12 ± 20, 95% CI 3.2-20.8, P = .02) and general function improved from 66 ± 25 to 80 ± 18 (difference 14 ± 22, 95% CI 5.0-23.6, P = .003). Self-perception and interaction domains remained unchanged (P > .2). For failures there was no significant change in Adult Strabismus-20 score on any domain (P > .4).

CONCLUSIONS

Successful correction of diplopia with prism is associated with improvement in strabismus-specific HRQOL, specifically reading function and general function.

Improvement in specific function-related quality-of-life concerns after strabismus surgery in nondiplopic adults

BACKGROUND

We have previously reported improvement in psychosocial scores after strabismus surgery on the patient-derived health-related quality of life (HRQOL) Adult Strabismus 20 (AS-20) questionnaire in adults with nondiplopic strabismus. Unexpectedly, we also found improvement in the function domain. The aim of the present study was to identify which specific aspects of function-related quality of life improved postoperatively.

METHODS

We retrospectively identified non diplopic adult patients with a history of childhood onset strabismus who underwent surgery and who had preoperative and 1-year postoperative AS-20 questionnaires (scored from 0 [worst] to 100 [best]). Change in scores for each item was evaluated using signed-rank tests.

RESULTS

A total of 20 patients were included. Of the 10 function-related AS-20 items, 9 showed significant mean improvement postoperatively (improvement ranged from 12.5 to 32.5 points, all P < 0.05). Rasch-derived mean scores improved in both reading function and general function domains (71.0 to 86.5 and 66.4 to 87.5, respectively; both P < 0.0001). Specific areas of function-related benefit were concentration, depth perception, hobbies, strain, reading, stress, and worry.

CONCLUSIONS

We found specific function-related quality of life benefits after strabismus surgery in nondiplopic adult patients, particularly those with childhood onset strabismus.

When the body is time: spatial and temporal deixis in children with visual impairments and sighted children

While there is mounting evidence explaining how concrete concepts are processed, the evidence demonstrating how abstract concepts are processed is rather scant. Most research illustrating how concrete and abstract concepts are processed has been obtained from adult populations. Consequently, not much is known about how these concepts are processed by children, especially those with sensorimotor impairments. This paper reports a study in which groups of children who were either visual-motor impaired (VMG), blind (BG), or sighted (CG) were requested to perform deictic gestures for temporal and spatial concepts. The results showed that: (i) spatial pointing was performed faster than temporal pointing across all groups of children; (ii) such difference in pointing times occurred also within groups; and (iii) the slowest pointing times were those of the blind children followed by the VMG and the CG children, respectively. Additionally, while CG children correctly performed the pointing tasks, VMG and, particularly, BG children relied on a form of deixis known as autotopological (or personal) deixis. The results thus suggest that deprivation or lack of sensorimotor experience with the environment affects the processing of abstract concepts and that a compensatory mechanism may be to rely on the body as a reference frame.

[The psychological consequences of amblyopia]

This is the review of references about problem of amblyopia and its psychosocial effects on children being cured. The study emphasies the need for psychological approach to problems that trouble children wearing glasses, suffering from strabismus and being cured by occlusion.

Strabismus and employment: the opinion of headhunters

PURPOSE

 The aim of this study was to determine the influence of strabismus on an individual's ability to find employment based on the opinion of Swiss headhunters.

METHODS

Forty Swiss headhunters retrieved from a Swiss online telephone directory were interviewed using a validated questionnaire in order to determine if strabismus would have an impact on a person's ability to find employment. Photographs of a strabismic man and woman as well as of other computer-generated facial anomalies could be downloaded from the Internet during the interview.

RESULTS

72.5% of headhunters judged that strabismic individuals would have more difficulties in finding a job than orthotropic persons. These difficulties were judged to be stronger in women than in men (P = 0.006), and in exotropic compared to esotropic persons (P = 0.01). Asked about seven facial anomalies, exotropia was found to have the third and esotropia the fourth (women) or fifth (men) most strongly negative impact on finding employment, after having strong acne and a visible missing tooth. Headhunters judged that persons with strabismus are significantly perceived as less attractive and less intelligent by potential employers.

CONCLUSION

Visible strabismus negatively influences individuals' ability to find a job and therefore has an impact on their economic status. Successful strabismus surgery realigns the visual axes, producing a normal facial appearance and therefore eliminating the negative impact of strabismus on employability.

Development of a quality-of-life questionnaire for adults with strabismus

PURPOSE

We report the development of a patient-derived, health-related quality-of-life (HRQOL) questionnaire for adults with strabismus.

DESIGN

Cross-sectional study.

PARTICIPANTS

Twenty-nine patients with strabismus in a first phase, and 32 patients with strabismus, 18 patients with other eye diseases, and 13 visually normal adults in a second phase.

METHODS

Individual patient interviews generated 181 questionnaire items. For item reduction, we asked 29 patients with strabismus to complete the 181-item questionnaire, analyzed responses, and performed factor analysis. Two prominent factors were identified, and the 10 items with the highest correlation with each factor were selected. The final 20-item questionnaire (10 psychosocial items and 10 function items) was administered to an additional 32 patients with strabismus (22 with diplopia, 10 without diplopia), 13 visually normal adults, and 18 patients with other eye diseases. A 5-point Likert-type scale was used for responses (never = 100, rarely = 75, sometimes = 50, often = 25, and always = 0). Median overall questionnaire scores and psychosocial and function subscale scores, ranging from 0 (worst HRQOL) to 100 (best HRQOL), were compared across groups.

MAIN OUTCOME MEASURES

The HRQOL questionnaire response scores.

RESULTS

Median overall scores were statistically significantly lower (worse quality of life) for patients with strabismus (56) compared with visually normal adults (95; P<0.001) and patients with other eye diseases (86; P<0.001). Median scores on the psychosocial subscale were significantly lower for strabismus patients (69) compared with visually normal adults (99; P<0.001) and patients with other eye diseases (94; P<0.001). For the function subscale, median scores were again significantly lower for strabismus patients (43) compared with visually normal adults (91; P<0.001) and patients with other eye diseases (78; P<0.001).

CONCLUSIONS

We have developed a 20-item, patient-derived, HRQOL questionnaire specific for adults with strabismus, with subscales to assess psychosocial and function concerns. This 20-item, condition-specific questionnaire will be useful for assessing HRQOL in individual strabismus patients and also as an outcome measure for clinical trials.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Contrast masking in strabismic amblyopia: attenuation, noise, interocular suppression and binocular summation

To investigate amblyopic contrast vision at threshold and above we performed pedestal-masking (contrast discrimination) experiments with a group of eight strabismic amblyopes using horizontal sinusoidal gratings (mainly 3c/deg) in monocular, binocular and dichoptic configurations balanced across eye (i.e. five conditions). With some exceptions in some observers, the four main results were as follows. (1) For the monocular and dichoptic conditions, sensitivity was less in the amblyopic eye than in the good eye at all mask contrasts. (2) Binocular and monocular dipper functions superimposed in the good eye. (3) Monocular masking functions had a normal dipper shape in the good eye, but facilitation was diminished in the amblyopic eye. (4) A less consistent result was normal facilitation in dichoptic masking when testing the good eye, but a loss of this when testing the amblyopic eye. This pattern of amblyopic results was replicated in a normal observer by placing a neutral density filter in front of one eye. The two-stage model of binocular contrast gain control [Meese, T.S., Georgeson, M.A. & Baker, D.H. (2006). Binocular contrast vision at and above threshold. Journal of Vision 6, 1224-1243.] was 'lesioned' in several ways to assess the form of the amblyopic deficit. The most successful model involves attenuation of signal and an increase in noise in the amblyopic eye, and intact stages of interocular suppression and binocular summation. This implies a behavioural influence from monocular noise in the amblyopic visual system as well as in normal observers with an ND filter over one eye.

The effects of strabismus on quality of life in adults

PURPOSE

As a first step in the development of a health-related quality of life (HRQOL) instrument, we conducted in-depth interviews to identify the specific concerns of adults with strabismus.

DESIGN

Prospective cross-sectional study.

METHODS

Thirty adults with strabismus, 17 with diplopia, and 13 without were recruited. Individual interviews, using 11 open-ended questions, were audiotaped, transcribed, and transcripts reviewed independently by three investigators. Phrases regarding how strabismus affected everyday life were grouped into topic areas and the frequency of each topic analyzed for subjects with and without diplopia.

RESULTS

A total of 1,508 phrases were extracted: 207 (14%) of 1,508 were excluded because they did not pertain to HRQOL. From the remaining 1,301 phrases, 48 topic areas were apparent. For patients with diplopia, the most frequently occurring topics were: nonspecific negative feeling (15/17; 88%) ("really hard"); general disability (15/17; 88%) ("affects everything"); and driving (14/17; 82%). In those without diplopia, the most frequently mentioned topics were appearance to others (12/13; 92%) ("people notice my eyes") followed by problems with eye contact (10/13; 77%) and interpersonal relationships (10/13; 77%). Of the topics that were common to both groups (n = 42), two of the most frequent were driving and nonspecific negative feeling.

CONCLUSIONS

Multiple individual interviews revealed many topics that negatively affect quality of life in patients with strabismus. The frequency and type of concerns confirm the importance of HRQOL assessment as an important aspect of strabismus management.

Stereopsis-dependent deficits in maximum motion displacement in strabismic and anisometropic amblyopia

Direction discrimination thresholds for maximum motion displacement (D(max)) have been previously reported to be abnormal in amblyopic children [Ho, C. S., Giaschi, D. E., Boden, C., Dougherty, R., Cline, R., & Lyons, C. (2005). Deficient motion perception in the fellow eye of amblyopic children. Vision Research, 45, 1615-1627; Ho, C. S., & Giaschi, D. E. (2006). Deficient maximum motion displacement in amblyopia. Vision Research, 46, 4595-4603]. We looked at D(max) thresholds for random dot kinematograms (RDKs) biased toward low- or high-level motion mechanisms. D(max) is thought to be limited, for high-level motion mechanisms, by the efficiency of object feature tracking and probability of false matches. To reduce the influence of low-level mechanisms, we determined thresholds also for a high-pass filtered version of the RDKs. Performance did not significantly differ between strabismic and anisometropic groups with amblyopia, although both groups performed significantly worse than the age-matched control group. D(max) thresholds were higher for children with poor stereoacuity. This was significant in both anisometropic and strabismic groups, and more robust for high-pass filtered RDKs than for unfiltered RDKs. The results imply that impairment of the extra-striate dorsal stream is a likely part of the neural deficit underlying both strabismic and anisometropic amblyopia. This deficit appears to be more dependent on extent of binocularity than etiology. Our findings suggest a possible relationship between fine stereopsis, coarse stereopsis, and motion correspondence mechanisms.

A new method for assessing motion-in-depth perception in strabismic patients

AIM

In strabismus clinics, stereoscopic depth perception is usually examined using static stimuli, but these stimuli do not necessarily allow assessment of the ability to perceive motion in depth. We assessed the ability to perceive motion-in-depth perception using a novel stereo motion test that we developed and compared with that to perceive static depth perception using a conventional stereo test in strabismic patients.

METHODS

To investigate motion-in-depth perception in patients with strabismus, we developed a stereo motion test using four types of computer-generated dynamic visual stimuli. Three of them are random dot stereograms of two parallel planes moving in depth. The patient is asked to indicate the planes' direction of rotation in depth (in the first and second types) or the presence/absence of motion-in-depth signal (in the third type). The fourth type of stimulus was a random dot stereogram of a rotating cylinder. The upper and lower parts of the cylinder rotate in opposite directions, and the patient is asked to indicate the position of the border between the two parts. Threshold disparity was defined as the disparity (relative disparity between the nearest and farthest points of the planes or the cylinder) that gives a critical level of performance with the method of limit. The conventional Titmus stereo test using static visual stimuli was used to assess static depth perception. The measurements were performed in 52 strabismic patients, aged between 4 and 38 years old, who visited Tokyo Medical University Hospital between January 2003 and July 2004.

RESULTS

The results showed a poor correlation in the threshold of individual patients between the stereo motion test and conventional Titmus stereo test. For example, the ability to perceive motion in depth (disparity threshold <500 sec of arc) was demonstrated in three of seven patients who were not able to perceive depth using static stimuli (0/9 for Titmus circle). These results suggest that the process of the dynamic element of binocular depth perception is preserved in some of the strabismic patients who lack static stereopsis.

CONCLUSION

This study indicates the importance of testing motion-in-depth perception as well as static depth perception in assessing stereopsis in strabismic patients.

Amblyopia and Strabismus Questionnaire (A&SQ): clinical validation in a historic cohort

BACKGROUND

We recently developed the Amblyopia & Strabismus Questionnaire (A&SQ) to assess the quality of life in amblyopia and/or strabismus patients, and evaluated its content and criterion validity. The A&SQ was now validated clinically by correlating its outcome with past and current orthoptic parameters in a historic cohort of amblyopia and/or strabismus patients.

METHODS

The cohort was derived from all 471 patients who were treated by occlusion therapy in the Waterland Hospital in Purmerend between 1968 and 1974 and born between 1962 and 1972. All children with insufficient visual acuity from the Waterland area had been referred to a single ophthalmologist and orthoptist. Of these, 203 were traced, and 174 filled out the A&SQ. In 137 of these, binocular vision, visual acuity, and angle of strabismus were reassessed 30-35 years after occlusion therapy. These clinical parameters were correlated with the five A&SQ domains: "distance estimation", "visual disorientation", "fear of losing the better eye", "diplopia", and "social contact and cosmetic problems".

RESULTS

The current acuity at distance of the amblyopic eye and reading acuity of the amblyopic eye correlated significantly with all five A&SQ domains (significance level P = 0.01-P = 0.05). Weaker correlations were found for binocularity. In spite of the expectation that stereopsis should strongly correlate with the domain "distance estimation", and angle of strabismus with the domain "social contact and cosmetic problems", the acuity of the amblyopic eye was the overall dominant parameter.

CONCLUSIONS

The adult acuity of the amblyopic eye seems the most important clinical determinant for quality of life in amblyopia and/or strabismus patients, even in domains of distance estimation, visual disorientation, and social contact and cosmetic problems, although intermediate determinants cannot be excluded.

Maturation of the sensitivity for luminance and contrast modulated patterns during development of normal and pathological human children

Any object may contain at least two spatio-temporal components referred to as first- and second-order, respectively, defined by spatial-temporal luminance modulation or by contrast, texture or depth modulation. This study investigates form sensitivity of infants, normals, premature or strabismic. A two-alternative forced-choice preferential looking procedure was used in monocular and binocular condition. Maturation profile for both stimuli was similar in the control group. Strabismic infants showed a vertical offset in maturation, which affected the second-order more severely. The pre-term group showed a lag of second-order sensitivity. Our results underline differences between first- and second-order processing.

Image segregation in strabismic amblyopia

Humans with naturally occurring amblyopia show deficits thought to involve mechanisms downstream of V1. These include excessive crowding, abnormal global image processing, spatial sampling and symmetry detection and undercounting. Several recent studies suggest that humans with naturally occurring amblyopia show deficits in global image segregation. The current experiments were designed to study figure-ground segregation in amblyopic observers with documented deficits in crowding, symmetry detection, spatial sampling and counting, using similar stimuli. Observers had to discriminate the orientation of a figure (an "E"-like pattern made up of 17 horizontal Gabor patches), embedded in a 7x7 array of Gabor patches. When the 32 "background" patches are vertical, the "E" pops-out, due to segregation by orientation and performance is perfect; however, if the background patches are all, or mostly horizontal, the "E" is camouflaged, and performance is random. Using a method of constant stimuli, we varied the number of "background" patches that were vertical and measured the probability of correct discrimination of the global orientation of the E (up/down/left/right). Surprisingly, amblyopes who showed strong crowding and deficits in symmetry detection and counting, perform normally or very nearly so in this segregation task. I therefore conclude that these deficits are not a consequence of abnormal segregation of figure from background.

The Amblyopia and Strabismus Questionnaire: English translation, validation, and subscales

PURPOSE

To establish the English-language version of the Amblyopia and Strabismus Questionnaire (ASQE).

DESIGN

Prospective cohort study.

METHODS

A structured translation process was followed to generate the ASQE, a 26-item instrument (originally in Dutch) containing five subscales for fear of losing the better eye, distance estimation, visual disorientation, double vision, and social contact and appearance. The ASQE was administered to 150 adults in a private practice setting. All had strabismus with or without amblyopia and visual acuity of 20/50 or better in at least one eye. Subjects also completed a brief disability questionnaire, and they were further characterized by levels of unilateral vision loss, diplopia, and asthenopia.

RESULTS

ASQE scores were highly correlated with the disability questionnaire outcomes (r = -.76, P < .0001). Internal consistency reliability (Cronbach alpha) of the subscales ranged from 0.80 to 0.92. Strong correlations were found between clinical characteristics and the ASQE (total score and subscale scores).

CONCLUSIONS

The ASQE showed good psychometric properties that are in line with those of the original instrument. This, combined with strong correlations between ASQE scores and clinical characterization of the participants, establishes the ASQE as a useful tool for use in populations with strabismus and/or amblyopia.

The VF-14 and Psychological Impact of Amblyopia and Strabismus

PURPOSE

To assess the impact of amblyopia, strabismus and glasses on subjective visual and psychological function among amblyopes.

METHODS

Questionnaires were administered to 120 teenagers with amblyopia (cases), with residual amblyopia after treatment, or with or without strabismus and 120 control subjects (controls) Cases underwent ophthalmic examination including cycloplegic refraction. Two questionnaires (visual function 14 [VF-14] and a newly designed eight-item questionnaire) were administered to assess the psychological impact score of general daily life, having a weaker eye, glasses wear, and current noticeable strabismus. Questionnaires were validated in 60 subjects in each group by a second administration of the questionnaire. The VF-14 scores, psychological impact scores, and clinical data were compared.

RESULTS

The VF-14 and psychological impact scores were highly reproducible. The mean VF-14 score for the control group was 95.5 and for the cases was 78.9 (P < 0.0001), but the scores did not correlate with the severity of amblyopia. The psychological impact score in general daily life was sensitive in discriminating between mild (median score 31) and moderate to severe (median score 56) amblyopes (P < 0.02). The cases segregated into two clear groups; those who scored high (large detrimental psychological impact) on psychological impact, with subjectively noticeable manifest strabismus, and those who scored low (low detrimental psychological impact), without noticeable strabismus. The subjective experience of patching treatment differentiated the two groups best of all.

CONCLUSIONS

Subjective visual and psychological functions are altered compared with normal subjects due to amblyopia, strabismus, and a previous unpleasant patching experience. The mean VF-14 score was similar to that previously published for patients with glaucoma. The study underlines that amblyopia and/or strabismus have an impact on teenagers' subjective visual function and well-being.

Effect of refractive surgery on binocular vision and ocular alignment in patients with manifest or intermittent strabismus

OBJECTIVE

To evaluate the effect of refractive surgery on binocular vision and ocular alignment in patients with manifest or intermittent strabismus, with or without vertical component.

SETTING

University Hospital Antwerp, Edegem, Belgium.

PATIENTS AND METHODS

13 patients (22 eyes) with strabismus underwent refractive surgery. Five of these patients presented with an esotropia and four of them with a small vertical deviation. Five patients had a manifest exotropia, of whom two presented with a small vertical deviation. Two patients had an intermittent exotropia with binocular vision, of whom one patient had a vertical deviation. One patient had a hypertropia with a dissociated vertical deviation.

RESULTS

Ocular alignment and binocular function remained unchanged postoperatively in all except two patients with high anisometropia who experienced an improvement in binocular function. In these patients, the preoperative manifest deviation became intermittent or latent after surgery, allowing fusion and stereopsis. Vertical deviation was found preoperatively in 8 of the 13 patients. This vertical deviation remained unchanged postoperatively, but improved in one patient with anisometropia.

CONCLUSION

Preoperative intermittent or manifest strabismus is not a contraindication for refractive surgery provided some specific recommendations are taken into account, such as an adequate preoperative orthoptic examination and aiming at emmetropia for both eyes.

The psychosocial benefits of corrective surgery for adults with strabismus

BACKGROUND

Few papers have addressed the psychological impact of strabismus in adults, with none comparing preoperative and postoperative data using standardised questionnaires relating surgical results and psychosocial outcomes.

METHODS

46 participants were seen at their 6 week preoperative and 3 month postoperative appointments. Standardised measures of anxiety and depression (Hospital Anxiety and Depression Scale), social anxiety (Derriford Appearance Scale), and quality of life (WHOQoLBref) were completed.

RESULTS

Preoperatively, levels of depression were comparable to relevant population norms; however, levels of general anxiety were slightly raised and levels of social anxiety and social avoidance were significantly poorer than population norms. Surgery resulted in significant improvements in psychosocial adjustment with improvements on all study variables for the participant group as a whole. The non-diplopic group made more significant gains than the diplopic group. Approximately one third of study measures were significantly correlated with the objective measure of eye misalignment preoperatively dropping to only one variable postoperatively. Calculations involving the subjective measure of eye misalignment and study variables showed the opposite pattern with five variables achieving significance postoperatively. There were no clear sex or age effects apparent in the data.

CONCLUSION

Strabismus surgery offers significant improvements to psychological and physical functioning.

Cerebral correlates of impaired grating perception in individual, psychophysically assessed human amblyopes

We investigated neuronal correlates of amblyopic deficits resulting from early onset strabismus or anisometropia by monitoring individual responses in retinotopically mapped cortical visual areas with functional magnetic resonance imaging (fMRI) in eight psychophysically assessed adult amblyopes. In lower visual areas (V1/V2), grating stimuli presented to the normal and the amblyopic eye evoked strong cortical responses, while responses to the amblyopic eye were progressively reduced in higher areas on the central visual pathway (V3a/VP; V4/V8; lateral occipital complex, LOC). Selective reduction for high spatial frequency gratings was especially obvious in LOC. This suggests that transmission of activity from the amblyopic eye is increasingly impaired while it is relayed towards higher processing levels. Elevated responses in parts of areas V1 and V2 to monocular stimulation of the amblyopic eye might be related to the spatial and temporal distortions experienced by some amblyopic subjects.

Investigation of metamemory dysfunctions in first-episode schizophrenia

A number of recent studies have suggested that schizophrenia patients share metamemory deficits, particularly, a decreased ability to distinguish between errors and correct responses in terms of response confidence (i.e., decreased confidence gap): patients are over-confident in errors while at the same time being under-confident in responses that are in fact correct. This, along with increased error rates, leads to an inflation of inaccurate but confidently held memories, which has been termed knowledge corruption. Previous studies on metamemory in schizophrenia patients predominantly tested chronic patients, leaving open the possibility that metamemory deficits stem partly from increased chronicity and long-term treatment. The primary aim of the current study was to establish whether a decreased confidence gap is also detectable in first-episode schizophrenia. For this purpose, a source memory task was administered to 30 first-episode patients with a diagnosis of schizophrenia or schizophreniform disorder, and 15 healthy control subjects. During encoding, items were read aloud by the experimenter and the participant in alternating order. For the recognition phase, participants were required to state the source of the item, and their confidence in their response. In agreement with previous studies, the patients displayed a decreased confidence gap, and increased knowledge corruption relative to controls. A reduced distinction between correct and incorrect information in metacognition is proposed to be a vulnerability factor for the development of delusions in schizophrenia.

Premorbid childhood ocular alignment abnormalities and adult schizophrenia-spectrum disorder

This study examined the relation between childhood ocular alignment deficits and adult psychiatric outcomes among children at high-risk for schizophrenia and controls. A sample of 265 Danish children was administered a standardized eye exam assessing strabismus and related ocular alignment deficits. All children whose mothers or fathers had a psychiatric diagnosis of schizophrenia comprised the first group (N=90). Children who had at least one parent with a diagnosis other than schizophrenia comprised the first matched control group (N=93). The second control group consisted of children with no parental diagnoses (N=82). In 1992, adult psychiatric outcome data were obtained for 242 of the original subjects. It was found that children who later developed a schizophrenia-spectrum disorder had significantly higher eye exam scale and strabismus scale scores compared to children who developed other non-psychotic psychopathology and children who did not develop a mental illness. The mean rank for children in the high-risk group (offspring of parents with schizophrenia) on the eye scale and the strabismus scale was greater than the mean rank for children in the matched control groups (both offspring of parents with other non-psychotic disorder and no mental illness), although the results failed to reach statistical significance. Results from this study suggest a premorbid relation between ocular deficits and schizophrenia-spectrum disorders in childhood prior to onset of psychopathology in adulthood. Strabismus may serve as a premorbid marker for spectrum disorders and may have implications for the understanding of early aberrant neurological development related to later schizophrenia-spectrum disorders.

The effect of strabismus on a young child's selection of a playmate

PURPOSE

This study investigated the effect of strabismus on a child's playmate selection.

METHODS

Photographs of orthotropic children aged 3-6 years were altered to simulate various magnitudes of strabismus. The pictures were arranged in pairs, one orthotropic child and one with strabismus. One hundred children aged 3-8 years viewed the photographs and were asked to select a playmate from each pair.

RESULTS

Chi-squared analysis found 23 children showed evidence that strabismus influenced their choices (p < 0.07). Of these 23, 12 preferred playmates with strabismus and 11 preferred orthotropic playmates. Chi-squared analysis of all subjects combined found decisions were not based on the magnitude or direction of strabismus.

CONCLUSIONS

As only 11% of the children consistently selected against playmates with strabismus, and about the same percentage preferred playmates with strabismus (12%), the presence of strabismus does not appear to be a significant factor in peer acceptance in this age group.

Location coding by the human visual system: multiple topological adaptations in a case of strabismic amblyopia

Amblyopia, a major cause of vision loss, is a developmental disorder of visual perception commonly associated with strabismus (squint). Although defined by a reduction in visual acuity, severe distortions of perceived visual location are common in strabismic amblyopia. These distortions can help us understand the cortical coding of visual location and its development in normal vision, as well as in amblyopia. The history of retinotopic mapping in the visual cortex highlights the potential impact of amblyopia. Theories of amblyopia include topological disarray of receptors in primary visual cortex, undersampling from the amblyopic eye compared with normal eyes, and the presence of anomalous retinal correspondence or multiple cortical representations of the strabismic fovea. We examined the distortions in a strabismic amblyope, using a pop-out localization task, in which normal observers made errors dependent on the visual context of the stimulus. The localization errors of the strabismic amblyope were abnormal. We found that none of the available theories could fully explain this one patient's localization performance. Instead, the observed behavior suggests that multiple adaptations of the underlying cortical topology are possible simultaneously in different parts of the visual field.

“Phase capture” in amblyopia: The influence function for sampled shape

This study was concerned with what stimulus information humans with amblyopia use to judge the shape of simple objects. We used a string of four Gabor patches to define a contour. A fifth, center patch served as the test pattern. The observers' task was to judge the location of the test pattern relative to the contour. The contour was either a straight line, or an arc with positive or negative curvature. We asked whether phase shifts in the inner or outer pairs of patches distributed along the contour influence the perceived shape. That is, we measured the phase shift influence function. Our results, consistent with previous studies, show that amblyopes are imprecise in shape discrimination, showing elevated thresholds for both lines and curves. We found that amblyopes often make much larger perceptual errors (biases) than do normal observers in the absence of phase shifts. These errors tend to be largest for curved shapes and at large separations. In normal observers, shifting the phase of inner patches of the string by 0.25 cycle results in almost complete phase capture (attraction) at the smallest separation (2 lambda), and the capture effect falls off rapidly with separation. A 0.25 cycle shift of the outer pair of patches has a much smaller effect, in the opposite direction (repulsion). While several amblyopic observers showed reduced capture by the phase of the inner patches, to our surprise, several of the amblyopes were sensitive to the phase of the outer patches. We used linear multiple regression to determine the weights of all cues to the task: the carrier phase of the inner patches, carrier phase of the outer patches and the envelope of the outer patches. Compared to normal observers, some amblyopes show a weaker influence of the phase of the inner patches, and a stronger influence of both the phase and envelope of the outer patches. We speculate that this may be a consequence of abnormal "crowding" of the inner patches by the outer ones.

The spatial localization deficit in visually deprived kittens

We measured the spatial localization abilities (alignment accuracy) of visually deprived kittens by use of similar spatially bandpass stimuli (Gaussian blobs) to those employed for the assessment of human amblyopes. The tests of vision were conducted on kittens reared with either strabismus or following different periods of monocular deprivation. As with amblyopic humans, the deficits in alignment accuracy were scaled in proportion to blob size and were not only considerably larger than those of grating acuity but also were not correlated with either the acuity or contrast sensitivity losses. Tests with stimuli of various contrast revealed that the deficits could not be explained in terms of the contrast sensitivity loss in this eye. The positional deficits that arise from anomalous visual development are independent of the contrast sensitivity loss and profound.

The management of strabismus in adults--II. Patient and provider perspectives on the severity of adult strabismus and on outcome contributors

PURPOSE

As part of a larger study intended to evaluate the management of strabismus in adults, we documented and compared patient and provider perspectives on the various factors that may contribute to treatment outcome and value of strabismus care.

METHODS

By completing a questionnaire, 170 patients with strabismus (ages 19 to 87 years) and 11 strabismus specialists who performed surgery on these patients each indicated the relative weight of several disease- and treatment-related contributors to the outcome and value of care. In addition, each respondent rated the severity of the strabismus before and after surgery.

RESULTS

Overall severity ratings improved as a result of surgery. The improvement perceived by the physicians was 5.1 +/- 1.7 on a 10-point scale and was larger than the 2.6 +/- 3.6 points improvement perceived by the patients ( P < 0.001). Patients and physicians expressed different views on the relative contributions to outcome and value (overall P < 0.001). Both groups indicated "the condition," "the physician," and "the procedures" as the largest contributors, but "condition" was perceived as more important by the physicians than by the patients ( P < 0.001), and "physician" was more important to the patients than to the physicians ( P < 0.001).

CONCLUSION

Although in approximate agreement on the main contributors to outcome and value, discrepancies exist between perspectives of patients and physicians on the relative weights of those contributors. Public information, education, and counseling may bring these perspectives better in line and ultimately improve both quality and patient satisfaction.

Social and emotional impact of strabismus surgery on quality of life in children

PURPOSE

Improved quality of life after strabismus surgery has been demonstrated in adults, but has not been extensively studied in children. The purpose of this study was to evaluate the psychosocial effects of childhood strabismus surgery.

METHODS

This was a prospective interventional study. A modified version of the RAND Health Insurance Study quality of life instrument was administered to parents or guardians of children with strabismus. The questionnaire was administered by telephone interviews conducted by trained staff before and 2 months after corrective surgery.

RESULTS

Ninety-eight children with a mean age of 4.5 (+/-3.3) years were studied. Reliability measures (Cronbach's alpha coefficients) indicate that the questionnaire has good internal consistency (alpha > 0.7 in most subscales). Compared with before surgery, significant improvements were noted after surgery, especially within the functional limitations (paired Student's t -test, P = 0.01), social relations ( P < 0.01), general health perceptions ( P < 0.01), and developmental satisfaction ( P < 0.01) subscales.

CONCLUSIONS

Parental proxies can provide meaningful measures of children's response to strabismus surgery. Statistically significant improvements were observed in social, emotional, and functional measures of the children's health status. As previously documented for adults, this study shows that psychosocial benefits afforded by strabismus surgery also contribute to an improvement in quality of life for children.

Local and non-local deficits in amblyopia: acuity and spatial interactions

Amblyopic vision is thought to be limited by abnormal long-range spatial interactions, but their exact mode of action and relationship to the main amblyopic deficit in visual acuity is largely unknown. We studied this relationship in a group (N=59) of anisometropic (N=21) and strabismic (or combined, N=38) subjects, using (1) a single and multi-pattern (crowded) computerized static Tumbling-E test with scaled spacing of two pattern widths (TeVA), in addition to an optotype (ETDRS chart) acuity test (VA) and (2) contrast detection of Gabor patches with lateral flankers (lateral masking) along the horizontal and vertical axes as well as in collinear and parallel configurations. By correlating the different measures of visual acuity and contrast suppression, we found that (1) the VA of the strabismic subjects could be decomposed into two uncorrelated components measured in TeVA: acuity for isolated patterns and acuity reduction due to flanking patterns. The latter comprised over 60% of the VA magnitude, on the average and accounted for over 50% of its variance. In contrast, a slight reduction in acuity was found in the anisometropic subjects, and the acuity for a single pattern could account for 70% of the VA variance. (2) The lateral suppression (contrast threshold elevation) in a parallel configuration along the horizontal axis was correlated with the VA (R2=0.7), as well as with the crowding effect (TeVA elevation, R2=0.5) for the strabismic group. Some correlation with the VA was also found for the collinear configuration in the anisometropic group, but less suppression and no correlation were found for all the vertical configurations in all the groups. The results indicate the existence of a specific non-local component of the strabismic deficit, in addition to the local acuity deficit in all amblyopia types. This deficit might reflect long-range lateral inhibition, or alternatively, an inaccurate and scattered top-down attentional selection mechanism.

Subnormal visual perception in school-aged ex-preterm patients in a paediatric eye clinic

PURPOSE

The aim of this study was to assess visual perception at school age of children born preterm with known lesions to the posterior visual pathways or with ophthalmologic signs that might indicate such lesions.

METHODS

The study group consisted of 91 patients born before the 37th gestational week. Visual perception was assessed using the TVPS-R (Test of Visual Perceptual Skills - Revised) and a structured interview. In addition, ophthalmologic and orthoptic examinations were performed.

RESULTS

On the test of visual perception, 67% of the patients had results below the third percentile of the American reference group. This is to be compared with 10% of Swedish full-term controls. Scores below the third percentile were observed in 87% of the patients with known brain lesions, 48% of those with strabismus without known brain lesion, and 86% of those with reduced visual acuity in the absence of strabismus and known brain lesion.

CONCLUSIONS

Reduced visual perception is common among children born preterm who have strabismus and/or reduced visual acuity, as well as in those with known brain lesions. This study emphasises the need to find tools to identify and assess those patients who have visual perceptual problems that may restrict their ability to meet the demands of daily life.

[Effect of strabismus on the quality of life in adults]

The aim of this paper was to prove by help of questionnaire the psychosocial problems in 26 adult patients operated for strabismus. We stated that the biggest difficulties of patients occurred by work and sport activities. The patients with diplopia also complained of difficulties with uncertain orientation, walking on steps and by locating the objects. The uncertainty by communication was also a great problem. The surgery fulfilled the expectations by 18 patients (69%), 8 patients (31%) were disappointed.

Deficits to global motion processing in human amblyopia

We investigated global motion processing in a group of adult amblyopes using a method that allows us to factor out any influence of the known contrast sensitivity deficit. We show that there are independent global motion processing deficits in human amblyopia that are unrelated to the contrast sensitivity deficit, and that are more extensive for contrast-defined than for luminance-defined stimuli. We speculate that the site of these deficits must include the extra-striate cortex and in particular the dorsal pathway.

Lateral interactions in amblyopia

We studied lateral neural interactions in strabismic (n=6) and anisometropic amblyopes (n=3) by measuring reductions in the perceived contrast of a foveally viewed Gabor centred in a horizontal array of closely neighboring Gabors. Strabismic amblyopes, but not anisometropic amblyopes, failed to show the reduction in perceived contrast typical of normal vision [J. Opt. Soc. Amer. A 15 (1998) 1733] when lateral contrast information is available at the same orientation and spatial frequency. The strabismic amblyopes also severely misperceive the regularity of the array of Gabors flanking the test stimulus. A normal eye could model the anomalous contrast perception of the amblyopic eye, by adding an equivalent amount of spatial distortion to the stimulus. The relationship between the observed anomalies for local contrast gain control and positional sensitivity is discussed.

Apparent motion processing in strabismic observers with varying levels of stereo vision

Deficits of motion processing have been reported in individuals with infantile strabismus. Here we examined motion perception in early and late onset strabismic individuals with varying levels of stereo acuity using the Fine Grain Motion Illusion (FGMI). The FGMI is an illusion of motion, where under some conditions, observers report exaggerated motion. It has been speculated that this illusion is due to the spatial range of cortical cells stimulated. We used this illusion to compare this motion exaggeration in the central vision of both the deviating and non-deviating eye of strabismic observers with control eyes. While individuals with early onset strabismus showed some mild exaggeration of motion, those with low stereo acuity, regardless of age at onset, showed significantly larger exaggeration of this motion illusion in both the deviating and non-deviating eyes as compared with control observers. These results might indicate that this illusion and stereopsis involve common mechanisms.

Study of the psychosocial aspects of strabismus

PURPOSE

To systematically evaluate the perception of psychosocial difficulties due to strabismus and the impact of corrective surgery in adolescents and young adults in India.

METHODS

Patients 15 to 25 years of age with childhood onset (< or = 5 years of age) of constant concomitant squint (> or = 30 prism diopters of deviation for distance) were included in the study. After a detailed orthoptic evaluation, demographic data of the patients and their parents were recorded. Postgraduate Institute Health Questionnaire N-2 (standardized in India) was administered to rule out neuroticism in the patients. Psychosocial problems faced by the patients were evaluated with a semistructured interview schedule. Patients were evaluated 3 months after surgery using a similar interview schedule to assess the psychological impact of surgery.

RESULTS

Eighty percent of both male and female patients had problems in their social life; 85% of the males and 75% of the females had personal problems due to squint. After surgery, a positive change in appearance was noticed by 97.5% and 95% noticed a change in self-esteem and self-confidence.

CONCLUSION

These patients had difficulties with self-image and interpersonal relationships, faced ridicule at school and work, and generally avoided activities that brought attention to their defect. Substantial changes were noticed in them after corrective surgery, and the differences in their scores before and after surgery were statistically significant.