Enhancing automated strabismus classification with limited data: Data augmentation using StyleGAN2-ADA.

In this study, we propose a generative data augmentation technique to overcome the challenges of severely limited data when designing a deep learning-based automated strabismus diagnosis system. We implement a generative model based on the StyleGAN2-ADA model for system design and assess strabismus classification performance using two classifiers. We evaluate the capability of our proposed method against traditional data augmentation techniques and confirm a substantial enhancement in performance. Furthermore, we conduct experiments to explore the relationship between the diagnosis agreement among ophthalmologists and the generation performance of the generative model. Beyond FID, we validate the generative samples on the classifier to establish their practicality. Through these experiments, we demonstrate that the generative model-based data augmentation improves overall quantitative performance in scenarios of extreme data scarcity and effectively mitigates overfitting issues during deep learning model training.

Michael Constantine Psellus (1020-1105 AD) and his definition of strabismus.

Strabismus was a known eye misalignment since the Hippocratic era (ca 5th century BC). Hippocrates and his followers were the first to introduce the hypothesis of a hereditary condition. Many ancient Greek physicians like Galen (ca 2nd AD) provided several definitions, while Paul of Aegina (625-690 AD) was the scholar who introduced a method to treat it. Paul used a full face mask and an oil lamb to guide the eyeballs toward the desired direction. It seems that this approach endured for centuries to come. During 11th century AD in Constantinople, the Byzantine scholar and politician Michael Constantine Psellus (ca 1020-1105 AD) composed a series of philosophical, religious, political and scientific treatises. Among his work stands a medical iambic didactic poem of 1732 lines, in which he had mentioned strabismus. Although he was not an oculist, he had managed to define strabismus. His definition was noted as such, "Strabismus is caused by a spasm of the bodies which move (the eye balls) and the oblique tendency of the muscles". Psellus was aware of the knowledge of the past and recorded what was still valid at that era, presenting a memorable definition. As his reference was completely neglected from the medical bibliography, our study aims to add him in the scientific chain of those who understood this disorder. This study aims to compose Psellus biography, present ancient Greek and Byzantine ophthalmology's opinion concerning strabismus and note Psellus' definition. The TLG and MedLine/PubMed databases were searched and the terms "strabismus" and "Psellus" were used as key words.

Epidemiology of strabismus surgery in a public hospital of the Brazilian Federal District / Epidemiologia da cirurgia de estrabismo em um hospital público de Brasília, Distrito Federal

Abstract Purpose: to determine the prevalence of different types of strabismus submitted to a surgical procedure in a public hospital in the Brazilian Federal District. Methods: Retrospective cross-sectional review of medical records of patients who underwent strabismus surgery performed by the same surgeon from 2004 to 2014. Incomplete records were excluded from the study. Variables included sex, age, type of strabismus, type of surgery, and re-surgeries. Strabismus was classified into three main types (esotropia, exotropia, and pure vertical deviation), and their subtypes. The type of surgery was determined by the number of muscles operated on (up to two, or more than two), the involvement of oblique and vertical rectus muscles, and muscle displacement. Results: 563 patients were reviewed and 531 were included in the study. The average age was 12.7 years, and females accounted for 54.4% of total patients. Esotropia was the most frequent type of strabismus (74%), followed by exotropia (23.7%) and pure vertical deviation (2.3%). The most frequent subtype of esotropia was infantile (49.1%), with 16.1% of these surgeries performed before the age of 2. Constant exotropia was the most frequent subtype of exotropia (27.8%). The prevalence of esotropia decreased with age, whereas that of exotropia increased. 52.3% of surgeries involved more than two muscles. An association between different types of deviation was found in 58.9% of patients. In cases of paralytic strabismus, the sixth nerve was the most affected (46%). Re-surgeries accounted for 10.7% of total surgeries. Conclusion s: Esotropias were the most common types of strabismus, especially infantile esotropia. Most cases were associated with other types of deviation, and needed more complex surgeries, involving more than two muscles. This study expects to contribute to the planning of health measures that may effectively improve the assistance provided to the population.

Resumo Objetivo: Determinar a prevalência dos diferentes tipos de estrabismo submetidos a intervenção cirúrgica em um hospital público de Brasília, Brasil. Métodos: Estudo retrospectivo de corte transversal de prontuários médicos dos pacientes submetidos a cirurgias de estrabismo por um mesmo cirurgião, de 2004 e 2014. Foram excluídos prontuários incompletos. Variáveis pesquisadas incluíram sexo, idade, classificação do estrabismo, tipo da cirurgia e reoperações. Os estrabismos foram classificados em três tipos principais (esotropia, exotropia e desvio vertical puro) e seus subtipos. Avaliação do tipo da cirurgia considerou o número de músculos operados (intervenção em até 2 ou em mais músculos), o envolvimento de músculos oblíquos, retos verticais e transposição muscular. Resultados: Foram avaliadas 563 pacientes e 531 foram incluídas na análise. A média de idade foi 12,7 anos e o sexo feminino respondeu por 54,4%. A esotropia foi o tipo de estrabismo mais frequente (74%), seguido pela exotropia (23,7%) e desvio vertical puro (2,3%). O subtipo de esotropia mais frequente foi o infantil (49,1%), com 16,1% destas cirurgias realizadas antes dos 2 anos de vida. A exotropia constante foi o subtipo mais observado (27,8%) de exotropia. A proporção de esotropia diminuiu com a idade, enquanto a de exotropia aumentou. 52,3% das cirurgias envolveram mais de dois músculos. Associação de diferentes tipos de desvio foi observada em 58,9% dos pacientes. Dentre os estrabismos paralíticos, o VI nervo foi o mais acometido (46%). Reoperações corresponderam a 10,7% do total. Conclusão: As esotropias foram os estrabismos cirúrgicos mais comuns, especialmente a esotropia infantil. A maioria dos casos estava associada a outras formas de desvio e necessitaram de cirurgias mais complexas, envolvendo mais de 2 músculos. Espera-se que dados do estudo possam contribuir no planejamento de ações de saúde efetivas para melhorar a assistência à população.

Choroidal Thickness in Strabismus and Amblyopia Cases.

PURPOSE: The aim of our study was to examine the effect of hypermetropia and anisometropic, exotropic, and esotropic amblyopia on choroidal thickness. METHODS: A prospective, cross-sectional, comparative study of 120 children under the age of 16 years was conducted. Choroidal thickness was measured in patients with hypermetropia, anisometropia, esotropia, exotropia, and controls. RESULTS: The mean subfoveal choroidal thickness in the control and hypermetropia groups was 323.9±69.0 µm and 348.9±64.5 µm, respectively. Mean choroidal thickness in amblyopic and fellow eyes was 387.4 and 351.9 µm in anisometropic, 353.8 and 338.7 µm in exotropic, 347.5 and 336.5 µm in esotropic, and 389.3 and 359.3 µm in esotropic+anisometropic groups, respectively. Choroid was significantly thicker in amblyopic eyes of anisometropic group compared to fellow (P=0.004) and control (P=0.03) eyes. The difference of choroidal thickness was not significant between both eyes and when compared to control eyes in the other groups. CONCLUSIONS: Anisometropic amblyopic eyes had thicker choroids compared to controls and fellow eyes. However the choroidal thickness was not significantly different between amblyopic and fellow eyes of esotropic or exotropic patients.

Strabismus.

Defining the type of strabismus creates a framework for work-up and management. Comitant esotropia is most commonly a childhood condition treated with glasses and surgery. Comitant exotropia is often a childhood condition that may require surgical correction. Microvascular disease is the most common cause of ocular cranial nerve palsies in adult patients.

[Interpretation the consensus of strabismus classification].

Strabismus is a deviation of the visual axes relative to each other and is a very common eye disease. Strabismus is not only a cosmetic disease but more importantly damage to visual acuity, binocular vision and stereopsis. There are many different strabismus forms. It is very difficult to accommodate all the different clinical forms with only one classification. Different author has different classification because of different concerns. In order to avoid clinical confusion and provide references for clinicians, literatures from mainstream domestic and international journals and new revised classification by Chinese Association for Strabismus and Pediatric Ophthalmology were reviewed in this paper.

Recent advances clarifying the etiologies of strabismus.

BACKGROUND: Strabismus is commonly encountered in neuro-ophthalmology practice. Adult patients may present with symptoms including disabling diplopia and decreased quality of life. Although presentation to the neuro-ophthalmologist often prompts a thorough workup for a neurologic basis of ocular misalignment, advances in orbital imaging and understanding of orbital mechanics have revealed novel mechanical causes. A goal of this review is to clarify mechanical mechanisms of strabismus that were formerly assumed be neurologic in origin. EVIDENCE ACQUISITION: The authors combine their own research and clinical experience with a literature review using PubMed. RESULTS: Aberrant paths of the extraocular muscles can lead to strabismus. The extraocular muscles have connective tissue pulleys that control muscle paths and are, in turn, influenced by the extraocular muscle orbital layers. Orbital connective tissues, including the pulleys, constrain extraocular muscle paths. Abnormalities of these tissues may lead to strabismus that is not due to neurologic pathology. Some extraocular muscles are divided into independent neuromuscular compartments, so that partial motor nerve lesions may manifest as selective denervation of only 1 compartment, complicating the presentation of neuropathic strabismus. CONCLUSIONS: Strabismus in adults due to nonneurologic causes can result from recently described abnormalities of the orbital connective tissue pulley system. Advances in understanding of compartmental extraocular muscle anatomy and innervation can explain cyclovertical strabismus in partial nerve palsies. Recognition of the underlying pathogenesis of the strabismus can lead to improved treatments.

Incidence, types, and lifetime risk of adult-onset strabismus.

OBJECTIVE: To describe the incidence and types of adult-onset strabismus in a geographically defined population. DESIGN: Retrospectively reviewed population-based cohort. PARTICIPANTS: All adult (≥19 years of age) residents of Olmsted County, Minnesota, diagnosed with new-onset adult strabismus from January 1, 1985, through December 31, 2004. METHODS: The medical records of all potential cases identified by the resources of the Rochester Epidemiology Project were reviewed. MAIN OUTCOME MEASURES: Incidence rates for adult-onset strabismus and its types. RESULTS: Seven hundred fifty-three cases of new-onset adult strabismus were identified during the 20-year period, yielding an annual age- and gender-adjusted incidence rate of 54.1 cases (95% confidence interval, 50.2-58.0) per 100 000 individuals 19 years of age and older. The 4 most common types of new-onset strabismus were paralytic (44.2% of cases), convergence insufficiency (15.7%), small-angle hypertropia (13.3%), and divergence insufficiency (10.6%). The incidence of adult-onset strabismus overall and its 4 most common forms significantly increased with age (P <0.001 for all), with a peak incidence in the eighth decade of life. The lifetime risk of being diagnosed with adult-onset strabismus was 4.0% in women and 3.9% in men. CONCLUSIONS: Paralytic strabismus was the most common subtype of new-onset adult strabismus in this population-based cohort. All of the most common forms of adult-onset strabismus increased with age, especially after the sixth decade of life. Further characterization of strabismus types found in this study is warranted to better define this disorder.

Adjustment versus no adjustment when using adjustable sutures in strabismus surgery.

PURPOSE: To compare long-term postoperative outcomes when performing an adjustment to achieve a desired immediate postoperative alignment versus simply tying off at the desired immediate postoperative alignment, when using adjustable sutures for strabismus surgery. METHODS: We retrospectively identified 89 consecutive patients who underwent a reoperation for horizontal strabismus with the use of adjustable sutures and also had a 6-week and 1-year outcome examination. In each case, the intent of the surgeon was to tie off and only to adjust if the patient was not within the intended immediate postoperative range. Postoperative success was predefined on the basis of the angle of misalignment and diplopia at distance and near. RESULTS: Of the 89 patients, 53 (60%) were adjusted and 36 (40%) were tied off. Success rates were similar between patients who were simply tied off immediately after surgery and those who were adjusted. At 6 weeks, the success rate was 64% for the nonadjusted group versus 81% for the adjusted group (P = 0.09; difference of 17%; 95% CI, -2% to 36%). At 1 year, the success rate was 67% for the nonadjusted group versus 77% for the adjusted group (P = 0.3; difference of 11%; 95% CI, -8% to 30%). CONCLUSIONS: Performing an adjustment to obtain a desired immediate postoperative alignment did not yield inferior long-term outcomes compared with tying off to obtain that initial alignment. If patients who were outside the desired immediate postoperative range had not been adjusted, it is possible that their long-term outcomes would have been worse. Therefore, overall, an adjustable approach may be superior to a nonadjustable approach.

[Clinical classification of incomitant strabismus].

Based on study of etiology, pathogenesis, clinical course, results of treatment of 489 patients aged from 1 till 73 years old with incomitant strabismus and integration of literature data clinical classification of incomitant strabismus was developed. Classification considers type and degree of extraocular muscle impairment (paralysis, palsy, pseudoparalysis, atypical forms), localization of damage (III, IV, VI cranial nerves, concurrent nerve damage), level of damage (cranial, orbital, combined), etiology and pathogenesis (local or systemic disease), age of manifestation (congenital, early and lately acquired), clinical manifestations (direction of globe deviation, forced head position, amblyopia, orbital fractures and soft tissue entrapment), presence of binocular diplopia (in primary or all gaze directions, in secondary gaze directions, without diplopia).

Vertical rectus surgery for Knapp class II superior oblique muscle paresis.

OBJECTIVE: To evaluate the efficacy of treating Knapp class II superior oblique muscle palsy with 7-mm nasal transposition of the ipsilateral inferior rectus muscle combined with recession of the contralateral inferior rectus muscle when the primary position hypertropia is 10 prism diopters (PD) or less. METHOD: A retrospective review of 8 consecutive patients with superior oblique muscle paresis who had nasal transposition of the inferior rectus muscle in the paretic eye and recession of the inferior rectus muscle in the nonparetic eye. Ocular motility, including objective and subjective torsion, were evaluated before and after surgery. RESULTS: The mean (SD) preoperative hypertropia was 5 PD (1.5) and 13.1 (3.6) PD in the primary position and downgaze, respectively. After surgery the mean (SD) hypertropia was 1.25 (1.0) and 3.25 (1.3) PD in the primary position and downgaze, respectively. The mean (SD) subjective excyclotropia decreased from 6.6 degrees (1.3 degrees) preoperatively to 0.5 degrees (0.9 degrees) after surgery, and there was a mean (SD) objective decrease in the excyclotorsion of the paretic eye by 7.8 degrees (1.4 degrees). All patients were diplopic before surgery and asymptomatic after surgery. CONCLUSION: Treatment with 7-mm nasal transposition of the ipsilateral inferior rectus muscle combined with recession of the contralateral inferior rectus muscle can effectively treat Knapp class II superior oblique muscle palsy when the primary position hypertropia is 10 PD or less.

In-utero exposure to smoking, alcohol, coffee, and tea and risk of strabismus.

In a prospective, population-based cohort study, the authors investigated the effect of in-utero exposure to maternal smoking and consumption of alcohol, coffee, and tea on the risk of strabismus. They reviewed medical records for children in the Danish National Birth Cohort identified through national registers as possibly having strabismus. Relative risk estimates were adjusted for year of birth, social class, maternal smoking, maternal age at birth, and maternal coffee and tea consumption. The authors identified 1,321 cases of strabismus in a cohort of 96,842 Danish children born between 1996 and 2003. Maternal smoking was associated with a significantly elevated risk of strabismus in the child, increasing with number of cigarettes smoked per day (<5 cigarettes/day: relative risk (RR) = 0.95, 95% confidence interval (CI): 0.80, 1.14; 5-<10 cigarettes/day: RR = 1.38, 95% CI: 1.12, 1.70; > or =10 cigarettes/day: RR = 1.90, 95% CI: 1.57, 2.30). Nicotine replacement therapy was not associated with strabismus risk (RR = 1.22, 95% CI: 0.92, 1.61). Light maternal alcohol consumption was inversely associated with strabismus risk, whereas maternal coffee and tea drinking were not associated with strabismus risk. In conclusion, smoking during pregnancy is associated with an increased risk of strabismus in the offspring. Conversely, light alcohol consumption is associated with decreased risk.