Clinical practice patterns for assessing children with learning difficulties: survey of eye health care professionals.

CLINICAL RELEVANCE: Understanding what aspects of vision or binocular vision may affect learning, and how these are assessed, is important for the eye health care professional assessing children with learning difficulties. It is vital that visual dysfunction is identified or excluded in these patients to ensure targeted and timely intervention. BACKGROUND: The aim of this study was to investigate similarities and differences between eye care professionals in the knowledge, attitudes and practice patterns, when evaluating children with learning difficulties. METHODS: This study was a cross-occupational, cross-sectional, predominantly quantitative internet-based survey. Ophthalmologists, optometrists, and orthoptists working in Australia were eligible to participate. A questionnaire comprising of 31 multiple-choice questions with up to 19 additional branching questions was distributed using REDCap in September 2022. RESULTS: A total of 130 responses were analysed (6 ophthalmologists, 84 orthoptists and 40 optometrists of whom 9 were practicing behavioural vision care). Most respondents assessed distance visual acuity (95%), near stereoacuity (85%), presence of strabismus (88%) and ocular movements (91%). Near vision was assessed less often (65%). Optometrists were most likely to measure colour vision (p < 0.002), accommodation and undertake a subjective refraction (each p < 0.001). Ophthalmologists were least likely to measure convergence (p = 0.041) but more likely to undertake a cycloplegic refraction (p = 0.044). More optometrists practicing behavioural vision care reported testing binocular vision (p = 0.026), fusional vergence (p < 0.001), saccades (p = 0.066), and smooth pursuit (p = 0.050) than other professions. There was a positive correlation between frequency and confidence level when assessing children with learning difficulties (ρ = 0.64). Respondents referred to paediatricians (39%), speech pathologists (30%), educational psychologists (29%) and general practitioners (29%). CONCLUSION: Despite similarities across occupations, there were differences in testing the vision and binocular functions of children with learning difficulties. Future research should aim to establish minimum standards for assessing this patient cohort to ensure consistent and relevant assessment.

Effectiveness of visual and acoustic biofeedback eccentric viewing training in conjunction with home exercises on visual function: a retrospective observational review.

The aim of this study is to evaluate the effectiveness of an eccentric viewing training program that combines biofeedback training using micro-perimetry with home exercises on multiple visual function parameters and to explore potential relationships between post-treatment visual function parameters. A retrospective observational review of 27 participants who underwent the training program was performed. Eligible participants were diagnosed with bilateral central scotomas secondary to age-related macular degeneration. All participants undertook up to 15 visual and acoustic biofeedback training sessions and were required to partake in traditional home exercises between sessions. The biofeedback training was conducted in the better eye using the Macular Integrity Assessment microperimeter (MAIA). Distance and near acuity, contrast sensitivity and fixation stability quantified by the P1 and P2 values and the 63% and 95% bivariate contour ellipse area (BCEA) before and after the rehabilitation program were recorded. Significant improvement was noted post-training for distance visual acuity (t(26) = 4938 p = .000), near visual acuity (Z = -4.461 p = .000), contrast sensitivity (Z = -3.647 p = .000) and fixation stability for all measures, including P1 (t(26) = -9.490 p = .000), P2 (t(26) = -7.338 p = 0.000), 63% BCEA (Z = 3.569 p = .000) and 95% BCEA (t(26) = 4.687 p = .000). Significant medium-to-large correlations were also found between most visual function variables. Visual and acoustic biofeedback in conjunction with home exercises has the potential to improve visual function parameters in patients with age-related macular degeneration and irreversible central vision loss.

'Poppers Maculopathy' and the adverse ophthalmic outcomes from the recreational use of alkyl nitrate inhalants: a systematic review.

OBJECTIVE: The aim of this systematic review and meta-analysis was to provide an overview of reported cases of poppers maculopathy and a statistical analysis of the clinical presentations, anatomical changes and treatment and follow-up of the rare disease. METHODS: A systematic search of CINAHL, Embase and PubMed databases was conducted, including a search of the grey literature. Data were pooled to provide a summary of the clinical characteristics and outcomes of poppers maculopathy. Studies were critically appraised using the Joanna Briggs Institute or the Authority, Accuracy, Coverage, Objectivity, Date, Significance checklists. RESULTS: Of the 493 articles obtained, 32 were included, consisting of 113 participants with a mean age of 40.2. Most patients were male with bilateral maculopathy and presented with either vision loss or a visual disturbance. Cessation of popper use was the most common form of management prescribed. The mean VA at baseline was 0.22 (logMAR units). For those followed-up, the mean VA significantly improved from 0.24 to 0.11 (Z = -5.800, p = <0.001). Bilateral yellow foveal spots were viewed on fundoscopy in 53 patients, and a sub-foveal disturbance of the ellipsoid layer was reported on spectral domain optical coherence tomography in 89 patients. By 6 months, SD-OCT anatomical changes mostly improved or resolved. CONCLUSION: Recreational users of poppers who develop maculopathy generally present with vision loss or a visual disturbance secondary to foveal disruption. Patients have a good visual prognosis, with cessation of poppers potentially having a role in improved outcomes. With the high prevalence of use among gay and bisexual men, awareness of related maculopathy and presenting symptoms by clinicians is important to mitigate side effects.

Adherence of patients with diabetic macular oedema to intravitreal injections: A systematic review.

The purpose of this study was to review adherence rates to intravitreal injections in the treatment of diabetic macula oedema and to identify factors associated with adherence. A systematic search of Embase, Medline, PsycINFO and CINAHL was conducted up to May 2020. Two authors independently screened, selected and appraised the studies. Seven articles on anti-VEGF treatment were found to meet the inclusion criteria. No studies were found on intravitreal corticosteroids or dexamethasone implants. Attendance rates varied between studies from 35% to 85%. The rate of missed or delayed attendance ranged from 14% to 51%, whereas 25% of patients were lost to follow-up at 12 months. Non-adherence was found to be multifactorial and included patient related reasons, demographic characteristics and clinical factors. Enablers to adherence included patient understanding of the disease and treatment. Further research in this area is warranted in order to better understand adherence in these patients and to improve patient outcomes.

A Randomized Trial to Increase the Assessment Accuracy of Glaucoma and Optic Disc Characteristics by Orthoptists.

INTRODUCTION: The aim of this study was to determine the accuracy of orthoptists when examining the optic disc for signs of glaucoma, and to explore the impact of targeted clinical education on accuracy. METHODS: In this randomized controlled trial, 42 monoscopic color optic disc images were presented to 46 orthoptists who assessed the likelihood of glaucoma as well as optic disc size, shape, tilting, vertical cup-to-disc ratio, cup shape, depth, presence of hemorrhage, peripapillary atrophy, and retinal nerve fiber layer. The level of agreement with specialist ophthalmologists was assessed. Participants were then randomly assigned to an experimental group (targeted postgraduate education on optic disc assessment) or to no intervention. The educational program was designed to increase knowledge of the characteristic features associated with glaucomatous optic neuropathy. All participants re-examined the included optic disc images after a period of 6 to 8 weeks. The primary outcome measure was a change in agreement between attempts. RESULTS: The education group showed significant improvements between attempts for identifying hemorrhages (P = .013), retinal nerve fiber layer defects (0.035), disc size (P = .001), peripapillary atrophy (P = .030), and glaucoma likelihood (P = .023). The control group did not show any statistically significant improvement. The intervention group showed significantly more improvement when identifying hemorrhages (P = .013), disc size (P = .001), disc shape (P = .033), and cup shape (P = .020) compared with the control group. DISCUSSION: Orthoptists who received additional postgraduate online education based on principles of adult learning were more accurate at assessing the optic disc for glaucoma. These results highlight the value of continuing education to optimize clinical practice in allied health professionals.

Experiences and perceptions of patients undergoing treatment and quality of life impact of diabetic macular edema: a systematic review.

Diabetic macular edema (DME) is a common cause of visual impairment. Current treatments for DME include laser photocoagulation, corticosteroids and Vascular Endothelial Growth Factor (VEGF) antagonists, which are administered via intravitreal injection. The purpose of this systematic review is to explore the experiences and perceptions of patients undergoing laser, corticosteroid implants and intravitreal injection treatment for DME and the impact on Quality of Life (QoL). A systematic search of the Embase, Medline, PsycINFO and Cinahl electronic databases was conducted to identify all studies with an unlimited date range, published in the English language, full text and incorporating human participants. Hand searching identified two articles. Following the application of the Critical Appraisal Skills Programme (CASP) Quantitative and Qualitative Research Checklist 21 articles were selected for inclusion, as they were deemed pertinent for the purpose of this review. Limited studies have examined DME patients' experiences and perceptions of treatment and QoL. The outcomes of these studies lack agreement on the effectiveness of treatment, treatment preferences and impact of QoL in patients with DME. Future research which enhances current knowledge will therefore serve to improve treatment outcomes and QoL in these patients.

Experiences of patients undergoing repeated intravitreal anti-vascular endothelial growth factor injections for neovascular age-related macular degeneration.

Current therapy to slow disease progression in patients with neovascular age-related macular degeneration (AMD) entails regular intravitreal anti-vascular endothelial growth factor (VEGF) injections, often indefinitely. Little is known about the burden imposed on patients by this repetitive treatment schedule and how this can be best managed. The aim of this study was to explore the psychosocial impact of repeated intravitreal injections on patients with neovascular AMD. Forty patients (16 males, 24 females) with neovascular AMD undergoing anti-VEGF treatment were recruited using purposive sampling from a private ophthalmology practice and public hospital in Melbourne. Patients were surveyed using the Macular Disease Treatment Satisfaction Questionnaire (MacTSQ; Bradley, Health Psychology Research Unit, Surrey, England) and underwent semi-structured, one-on-one interviews. Interview topics were: treatment burden and satisfaction; tolerability; barriers to adherence; treatment motivation; and patient education. Interviews were audio recorded and thematic analysis performed using NVivo 10 (QSR International, Doncaster, Australia). Patients recognised the importance of treatment to preserve eyesight, yet experienced significant psychosocial and practical burden from the treatment schedule. Important issues included treatment-related anxiety, financial considerations and transport burden placed on relatives or carers. Many patients were restricted to sedentary activities post-injection owing to treatment side effects. Patients prioritised treatment, often sacrificing family, travel and social commitments owing to a fear of losing eyesight if treatment was not received. Whilst anti-VEGF injections represent the current mainstay of treatment for neovascular AMD, the ongoing treatment protocol imposes significant burden on patients. An understanding of the factors that contribute to the burden of treatment may help inform strategies to lessen its impact and assist patients to better manage the challenges of treatment.

Retinal Vascular Caliber and Kidney Function in Children and Adolescents with Type 1 Diabetes.

PURPOSE: To evaluate the relationship between retinal vascular caliber and kidney function in a cohort of Australian children and adolescents with type 1 diabetes. METHODS: This was a cross-sectional study of 483 children and adolescents with type 1 diabetes, aged 7-18 years. An audit of medical files of participants who attended the Royal Children's Hospital, Melbourne, between January 2009 and March 2014 was performed. Albumin to creatinine ratio (ACR) was acquired through spot urine samples and microalbuminuria was classified as ACR >3.5 mg/mmol in females and >2.5 mg/mmol in males. Retinal vascular caliber was measured using a standardized protocol and later summarized as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE). RESULTS: CRAE was significantly narrower in participants with microalbuminuria compared to those with normo-albuminuria in crude analysis (mean ± standard deviation 159.07 ± 9.90µm vs 164.49 ± 12.45 µm; p = 0.006). After adjustment for key confounders and known or potential mediators of microalbuminuria (age, sex, ethnicity, hemoglobin A1c, systolic blood pressure, total cholesterol, body mass index, duration of diabetes and CRVE) the association between narrower CRAE and microalbuminuria was attenuated and was no longer significant (95% confidence interval 0.94-1.02, p = 0.222). No significant associations between CRVE or arteriole-to-venule ratio and microalbuminuria were observed in univariate or multivariate models. CONCLUSIONS: After adjustment for potential confounding variables, retinal vascular caliber was not significantly associated with microalbuminuria in this sample of children and adolescents with type 1 diabetes. Future prospective longitudinal research is warranted to further evaluate these findings.

Vascular risk factors are associated with retinal arteriolar narrowing and venular widening in children and adolescents with type 1 diabetes.

BACKGROUND: The aim of the study was to describe the relationship of retinal arteriolar and venular calibre with vascular risk factors in children and adolescents with type 1 diabetes. METHODS: In this hospital-based cross-sectional study, the medical files of 483 children and adolescents with type 1 diabetes were audited to collect retinal images and relevant clinical data. Retinal vascular calibre was measured using standardised protocols. RESULTS: After multivariable adjustments, a vascular risk profile that included: older age, higher serum creatinine, higher systolic blood pressure (SBP), higher body mass index (BMI), abnormal estimated glomerular filtration rate (eGFR), lower high-density lipoproteins (HDL) cholesterol, longer duration of diabetes and higher serum sodium was associated with narrower central retinal artery equivalent (CRAE) (95% CI=-4.10/-0.76, p=0.004). A specific risk profile, including higher total cholesterol level, higher BMI, lower physical activity level, higher HbA1c, higher triglyceride levels, female gender and lower socio-economic status, was associated with wider central retinal vein equivalent (CRVE) (95% CI=1.14/5.62, p=0.003). CONCLUSIONS: In summary, these findings support evidence that cardiovascular disease may have its origins early in life. Prospective and/or intervention studies are required to confirm whether the observed associations are involved in the causal pathway for retinal vascular calibre.

Accuracy and Efficiency of Orthoptists in Comprehensive Pediatric Eye Examinations.

INTRODUCTION AND PURPOSE: To investigate the level of agreement between orthoptists and medical practitioners in the comprehensive eye examination of children seen in an orthoptist-led triage clinic. PATIENTS AND METHODS: Patient records over a 6-month period were retrospectively reviewed. Those with a presenting complaint related to vision or ocular motility were triaged into the orthoptist-led clinic and included in the study. Patients who did not meet the triage protocol and those who were not assessed by a medical practitioner at a subsequent appointment were excluded from analysis. The clinical findings from the orthoptist and medical practitioner were collected and compared. RESULTS: In total, sixty-three patients were reviewed during the 6-month period and met the inclusion criteria. After the initial comprehensive eye examination with an orthoptist, thirty-two were discharged from hospital and thirty-one were asked to return for a review appointment with a medical practitioner. Agreement between the orthoptists and medical practitioners for the diagnosis of strabismus and/or amblyopia was 84.6% (κ = 0.649, P < 0.001). There was strong agreement between orthoptists and medical practitioners for refractive error of the right eye [τ (19) = 0.352, P = 0.729] and left eye [τ (19) = 1.785, P = 0.090]. Fundus examination comparisons between the orthoptists and medical practitioners showed very high agreement (95.7%). CONCLUSIONS: Orthoptists have the skills necessary to provide comprehensive care of children referred for ocular motility and/or vision related disorders. There was close agreement between orthoptists and medical practitioners when performing comprehensive eye examinations.

Prevalence and risk factors for diabetic retinopathy in a hospital-based population of Australian children and adolescents with type 1 diabetes.

BACKGROUND: The aim of this study was to investigate the prevalence of, and traditional and emerging risk factors associated with, retinopathy in a hospital-based population of Australian children and adolescents with type 1 diabetes. METHODS: This was a cross-sectional study of 483 children and adolescents with type 1 diabetes. Medical files were audited to collect all relevant clinical data. Diabetic retinopathy was assessed from colour retinal images by an ophthalmologist. RESULTS: Diabetic retinopathy was observed in 11 (2.3%) participants. Logistic regression revealed that the principal components analysis derived risk profile of: higher serum creatinine, older age, higher systolic blood pressures, higher body mass index, abnormal estimated glomerular filtration rate (eGFR) (<59 mL/min), lower high density lipoproteins (HDL) cholesterol, higher serum sodium, longer duration of diabetes and narrower retinal arteriolar calibre was associated with diabetic retinopathy (ExpB=2.60, 95% CI 1.36/4.96, p=0.004). CONCLUSIONS: These results support the concept that the pathogenesis of diabetic retinopathy is likely due to the combined influence of various risk factors, many already identified.

Physical Activity, Sedentary Behaviors, and Retinal Vascular Caliber in Children and Adolescents With Type 1 Diabetes.

PURPOSE: The aim of this study was to investigate associations of physical activity and sedentary behaviors with retinal vascular caliber in children and adolescents with type 1 diabetes. DESIGN: This was a hospital-based cross-sectional study. METHODS: A study of 122 children and adolescents with type 1 diabetes was conducted over an 8-month period. Self-reported physical activity time and time spent watching TV or playing computer or video games were obtained using interviewer-administered questionnaires. Retinal vascular caliber was measured by a trained grader using a standardized protocol and later summarized as central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) using a semiautomated computer program. RESULTS: After adjusting for confounders (age, sex, ethnicity, body mass index, systolic blood pressure, HbA1c, maternal smoking status, age at which cow's milk was introduced, and CRVE/CRAE, respectively), narrower CRAE was independently related to more time spent playing computer/video games [ExpB = -3.85; 95% confidence interval (CI), -6.41 to -1.29; P = 0.004], whereas wider CRVE was independently related to lower physical activity level (ExpB = -1.08; 95% CI, -2.01 to -0.15; P = 0.03) and more time spent playing computer/video games (ExpB = 4.72; 95% CI, 0.52-8.92; P = 0.02). Television viewing time was not associated with retinal vascular caliber after adjustment. CONCLUSIONS: The results of this study suggest that physical activity and sedentary behaviors in the form of "screen viewing time" are associated with retinal vessel caliber early in life. These results suggest that retinal vascular caliber may provide prognostic information beyond current traditional cardiovascular risk factors. Future longitudinal and interventional studies are warranted to evaluate the relevance of these observations.

Dietary patterns and retinal vascular calibre in children and adolescents with type 1 diabetes.

PURPOSE: To examine the association between dietary patterns and retinal vascular calibre in children and adolescents with type 1 diabetes. METHODS: A hospital-based cross-sectional study of 83 children and adolescents with type 1 diabetes was conducted over an 8-month period. Dietary patterns were extracted using principal components analysis from completed food frequency questionnaires. Retinal vascular calibre was measured by a trained grader using a standardized protocol and later summarized as central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE) using a semi-automated computer program. RESULTS: Three major dietary patterns were identified as follows: (1) processed foods, (2) plant-based foods and (3) vegetable/fish avoidance pattern. The processed pattern had high component loadings for processed meats and high fat takeaway foods. The plant-based pattern had high component loadings for a number of fruits including, but not limited to, pineapple, grapes oranges and mangos as well as a smaller number of vegetables, including beans and leeks. The vegetable and fish avoidance pattern had high inverse component loadings for canned and fresh fish as well as a number of vegetables including, but not limited to, pumpkin, green beans, broccoli, sweet potato and cabbage. Adjusted regression analysis revealed the 'vegetable/fish avoidance' dietary pattern was associated with a wider CRVE (ExpB = 3.67, 95% CI = 0.11/7.24, p = 0.039). After multivariable adjustments, a vascular risk profile that included: older age, higher BMI, higher systolic blood pressure, greater gestational age, longer screen viewing time, lower maternal education level, lower physical activity levels and lower high-density lipoproteins concentrations were more likely to display narrower CRAE (ExpB = -2.43, 95% CI = -4.92/0.06, p = 0.041). CONCLUSIONS: This study provides the first evidence for a diet-calibre relationship in children and adolescents with type 1 diabetes. This outcome has potential public health implications, as promotion of healthy eating patterns in children and adolescents might attenuate changes in microvasculature that have been related to an increased risk of microvascular disease, such as retinopathy, in adulthood. Additional studies are warranted to explore and validate this novel finding.

Experiences of patients undergoing anti-VEGF treatment for neovascular age-related macular degeneration: a systematic review.

Current therapy to slow disease progression in patients with neovascular age-related macular degeneration (AMD) often entails intra-vitreal injection of an anti-vascular endothelial growth factor (VEGF) agent, that begins with a three-month loading phase of four weekly injections followed by regular monthly visits with clinician-determined re-treatment. The effects of AMD on quality of life and visual function have been extensively reported in the literature, however, less is known about the burden imposed on patients by the arduous and often indefinite treatment schedule which habitually follows a diagnosis of wet AMD. To date, no systematic review has been conducted of research investigating patients' experiences of anti-VEGF treatment for AMD. A systematic search of the Embase, Medline, PsycINFO and PubMed electronic databases was undertaken to identify all studies between January 2004 and December 2013, published in the English language and involving human participants. A hand-search of an additional four journals was conducted. Ten articles were identified for inclusion in this review. A critical appraisal was undertaken using the Critical Appraisal Skills Programme Qualitative Research Checklist and the results synthesised to form a narrative review. Few studies to date have investigated patients' experiences of treatment for AMD. These studies have focused primarily on patients' experiences of the injection procedure with respect to pain and anxiety. Anticipated discomfort is often greater than actual discomfort experienced during intra-vitreal injection. However, different stages of the treatment procedure produce varying levels of patient discomfort. No one method of anaesthesia has consistently been shown to be more effective in reducing discomfort associated with treatment. Common reasons underlying patient apprehension surrounding treatment include the thought of having an injection, fear of losing eyesight and fear of the unknown. Whilst these studies have not been without their methodological limitations, they provide a platform for further exploration of the patient experience.

Management of intermittent exotropia strabismus of the divergence excess type.

A number of surgical and non-surgical options are available for patients with intermittent exotropia. This paper provides a review of this strabismus condition, particularly divergence excess type, with a particular emphasis on treatment. We highlight that there is a lack of evidence for best practice and a need for not only high-quality clinical studies but also a better understanding of current practice patterns among clinicians so as to inform future research.

The base-to-base induced-tropia prism test for detection of amblyopia: a pilot study.

PURPOSE: To investigate the accuracy of the base-to-base prism test (BBPT), which entails inducing an esotropia with the use of base-in prisms before each eye, in the diagnosis of amblyopia. METHODS: Participants were consecutive patients recruited from a pediatric ophthalmology practice who were able to perform logMAR acuity testing. All participants underwent an orthoptic examination, including logMAR visual acuity testing, and a sensorimotor evaluation. Patients with an interocular difference of 2 or more lines were considered to have amblyopia. Fixation preference was assessed by use of both the vertical fixation test and the BBPT. The agreement between the BBPT and visual acuity was analyzed and compared with the agreement between the vertical fixation test and visual acuity. RESULTS: Fifty-one consecutive patients aged 4 to 17 (mean, 9.8 years; SD ± 3.4) were included, of whom 11 were diagnosed with amblyopia. Kappa analysis showed moderate but significant agreement between the BBPT and logMAR (κ = 0.453, p = 0.001), whereas the vertical fixation test demonstrated only a fair agreement (κ = 0.254, p = 0.061). The overall sensitivity for the BBPT was 72.7% (95% confidence interval [95% CI], 43.4%-90.3%) but only 40% for the vertical fixation test (95% CI, 16.8%-69.7%). For the BBPT, specificity was 80% (95% CI, 65.2%-89.5%); for the vertical fixation test, 78% (95% CI, 63.3%-88.0%). CONCLUSIONS: The BBPT appears to be more sensitive than the vertical fixation test for detecting amblyopia in our patient population. The 2 tests had similar specificity.

The use of distance stereoacuity assessment in determining the effectiveness of minus lenses in intermittent exotropia.

PURPOSE: Minus lens treatment has been advocated for intermittent exotropia to prevent progression and has been found to be effective in improving the control of the deviation in the distance. However, the effectiveness of this treatment is difficult to ascertain because of the lack of standardized outcome measures. Distance stereoacuity has been reported to be a reliable assessment of control of intermittent exotropia. In this study, its role as an outcome measure in the efficacy of minus lens treatment was examined by the use of the Frisby-Davis Distance stereotest. METHODS: Patients (n = 24) with intermittent exotropia participated. Their distance stereoacuity was tested with the Frisby-Davis Distance stereotest at baseline and with varying minus lens powers (of -1, -2 and -3 D) that were tested randomly, as were the distance binocular visual acuity and angle of deviation. RESULTS: Varying minus lens powers had a significant effect on the angle of deviation and binocular visual acuity but not distance stereoacuity. However, both measures of binocularity, distance stereoacuity, and binocular visual acuity tended to diminish with the stronger minus lens power of -3 D. Participants actually demonstrated difficulty in accommodating through the stronger lenses. CONCLUSIONS: Distance stereoacuity (and binocular visual acuity) cannot reliably be used to determine the optimum minus lens strength that could be used in these patients to reduce the angle of deviation and regain binocularity in the distance. An additional observation was made that stronger lenses should perhaps be avoided to prevent binocular and visual discomfort.

The fixation target influences the near deviation and AC/A ratio in intermittent exotropia.

PURPOSE: Divergence excess intermittent exotropia is thought to comprise 2 types of deviation, simulated and true. It is believed that simulated divergence excess is akin to a basic deviation but is controlled at near through accommodative and adaptive fusional vergences. While fixation target detail is known to influence accommodation and subsequently deviation size, no previous study has investigated the effect of the fixation target on the AC/A ratio in intermittent exotropia and its influence on the deviation's classification. METHOD: Twenty-five participants with intermittent exotropia underwent near and distance measurement before and after 45 minutes of occlusion. The near angle was also measured through +3.00 D lenses, and using 2 different sized targets, an N60-equivalent "butterfly" picture and N5 print. The gradient AC/A ratio was calculated for each target. RESULTS: There was a significant difference between the measurements using the 2 targets, t(24) = 8.3, p < or = <0.001. On average, the near angle was 8.8(Delta) greater using the N5 print. This also resulted in a significant difference for the AC/A ratio, t(24) = -8.4, p < 0.001, the mean with the target being 3.6(Delta):1D, as compared to 6.6(Delta):1D with the N5 print. CONCLUSIONS: Through careful control of accommodation by ensuring relaxation with plus lenses to clear N5 print, we revealed increases in the AC/A ratio and unmasked deviations that would otherwise have been considered to be characteristic of true divergence excess. Simulated and true deviations are possibly part of a continuum and clinical delineation may be influenced by testing artefact.

Atropine treatment of amblyopia: is a swap in fixation necessary?

PURPOSE: To investigate the impact of fixation on vision outcomes in patients with amblyopia undergoing atropine treatment and the validity of the "cyclo-swap test" (CST) as a method of predicting atropine efficacy. METHOD: Sixteen children with amblyopia were included. The initial examination included a vision assessment and CST, in which fixation was assessed at 1/3 m, 6 m, and at distances less than 1/3 m. Children were treated for 10 weeks and reviewed at 5-week intervals with cessation of atropine 4 days prior. Vision and fixation were assessed at the follow-up visits. Children demonstrating no fixation swap initially were additionally observed after 1 week of atropine treatment under maximum cycloplegia. RESULTS: Eight children demonstrated a fixation swap (FS group) to the amblyopic eye during the CST at either 1/3 or 6 m, and 8 demonstrated no fixation swap (NFS group). By the end of the 10-week treatment period, both groups demonstrated a mean visual acuity improvement of between 2 and 3 lines (FS = 0.22 log units; NFS = 0.27 log units). Six of the 8 children in the NFS group demonstrated improvement in vision, all of whom also demonstrated a fixation swap at some stage. CONCLUSION: Vision improvement in patients using atropine is likely to be attributable to a fixation swap that occurs during the treatment phase. The CST performed at 1/3 and 6 m has little value in predicting improvements in vision; however, when performed at distances of less than 1/3 m, it may provide valuable clinical information about atropine efficacy.

Recurrence of intermittent exotropia: factors associated with surgical outcomes.

INTRODUCTION: The surgery of choice for intermittent exotropia (XT) continues to be debated, with little evidence that one procedure provides a more successful outcome than the other in the longer term. Many factors, however, may potentially influence the outcome of strabismus surgery for intermittent XT. This study aimed to investigate factors associated with the recurrence of an exo-deviation following horizontal muscle surgery for intermittent XT of the divergence excess type. METHODS: We retrospectively reviewed the medical histories of patients who underwent surgery for the correction of intermittent XT between January 1998 and June 2005. The factors analyzed were as follows: sex, age of onset, age at initial surgery, family history, size of preoperative deviation, near binocular single vision, amblyopia, oblique dysfunction, refractive error, type of surgery, and postoperative alignment. RESULTS: Eighty-nine patients were included in the final analysis. Of these, 19 demonstrated recurrence of their deviation. The mean follow-up period was 2 years. None of the factors analysed appeared to influence the outcome of intermittent XT surgery. CONCLUSION: We found that no single factor influenced patients' responses to the surgical treatment of intermittent XT. To address controversies and improve the evidence base regarding surgical intervention of this condition, randomized controlled trials are needed and justified because the results indicate that it would be relatively safe to randomly allocate patients to groups who could receive differing treatments so as to determine optimum management strategies.