Molecular subtype and growth hormone effects on dysmorphology in Prader-Willi syndrome.

Prader-Willi syndrome (PWS) affects 1/15,000-1/30,000 live births and is characterized by lack of expression of paternally inherited genes on 15q11.2-15q13 caused by paternal deletions, maternal uniparental disomy (UPD), or imprinting defects. Affected individuals have distinct physical features, and growth hormone (GH) deficiency occurs in some individuals with PWS. The aim of this study is to test the hypotheses that (a) individuals with deletions and UPD have different physical and dysmorphic features, (b) individuals treated with GH have different physical and dysmorphic features than those not treated, and (c) GH treatment effects are different for individuals with UPD in comparison to those with deletions. Study participants included 30 individuals with deletions or UPD, who did or did not have GH treatment. Participants' molecular abnormalities were determined by molecular and cytogenetic analysis. Clinical data were obtained by a single dysmorphologist. Individuals with deletions were found to be heavier (p = .001), taller (p = .031), with smaller head circumferences (p = .042) and were more likely to have fair skin and hair than their family members (p = .031, .049, respectively) compared to UPD patients. Females with deletions more commonly had hypoplastic labia minora (p = .009) and clitoris (.030) in comparison to those with UPD. Individuals who received GH in both deletion and UPD groups were taller (p = .004), had larger hands (p = .011) and feet (p = .006) and a trend for a larger head circumference (p = .103). Interestingly, the GH-treated group also had a lower rate of strabismus (esotropia [p = .017] and exotropia [p = .039]). This study showed statistically significant correlations between phenotype and molecular subtypes and also between phenotype and GH treatment.

Normal Topography and Binocularity of the Superior Colliculus in Strabismus.

In subjects with alternating strabismus, either eye can be used to saccade to visual targets. The brain must calculate the correct vector for each saccade, which will depend on the eye chosen to make it. The superior colliculus, a major midbrain center for saccade generation, was examined to determine whether the maps serving each eye were shifted to compensate for strabismus. Alternating exotropia was induced in two male macaques at age 1 month by sectioning the tendons of the medial recti. Once the animals grew to maturity, they were trained to fixate targets with either eye. Receptive fields were mapped in the superior colliculus using a sparse noise stimulus while the monkeys alternated fixation. For some neurons, sparse noise was presented dichoptically to probe for anomalous retinal correspondence. After recordings, microstimulation was applied to compare sensory and motor maps. The data showed that receptive fields were offset in position by the ocular deviation, but otherwise remained aligned. In one animal, the left eye's coordinates were rotated ∼20° clockwise with respect to those of the right eye. This was explained by a corresponding cyclorotation of the ocular fundi, which produced an A-pattern deviation. Microstimulation drove the eyes accurately to the site of receptive fields, as in normal animals. Single-cell recordings uncovered no evidence for anomalous retinal correspondence. Despite strabismus, neurons remained responsive to stimulation of either eye. Misalignment of the eyes early in life does not alter the organization of topographic maps or disrupt binocular convergence in the superior colliculus.SIGNIFICANCE STATEMENT Patients with strabismus are able to make rapid eye movements, known as saccades, toward visual targets almost as gracefully as subjects with normal binocular alignment. They can even exercise the option of using the right eye or the left eye. It is unknown how the brain measures the degree of ocular misalignment and uses it to compute the appropriate saccade for either eye. The obvious place to investigate is the superior colliculus, a midbrain oculomotor center responsible for the generation of saccades. Here, we report the first experiments in the superior colliculus of awake primates with strabismus using a combination of single-cell recordings and microstimulation to explore the organization of its topographic maps.

Rectus Extraocular Muscle Size and Pulley Location in Concomitant and Pattern Exotropia.

PURPOSE: To determine whether rectus extraocular muscle (EOM) sizes and pulley locations contribute to exotropia, we used magnetic resonance imaging (MRI) to measure these factors in normal control participants and in patients with concomitant and pattern exotropia. DESIGN: Prospective case-control study. PARTICIPANTS: Nine patients with concomitant exotropia, 6 patients with pattern exotropia, and 21 orthotropic normal control participants. METHODS: High-resolution surface-coil MRI scans were obtained in contiguous, quasicoronal planes. Rectus pulley locations were determined in oculocentric coordinates for central gaze, supraduction, and infraduction. Cross sections in 4 contiguous image planes were summed and multiplied by the 2-mm slice thickness to obtain horizontal rectus posterior partial volumes (PPVs). MAIN OUTCOME MEASURES: Rectus pulley locations and horizontal rectus PPVs. RESULTS: Rectus pulleys were located differently in patients with A-pattern, versus V- and Y-pattern, exotropia. The lateral rectus (LR) pulleys were displaced significantly superiorly, the medial rectus (MR) pulleys were displaced inferiorly, and the inferior rectus pulleys were displaced laterally in A-pattern exotropia. However, the array of all rectus pulleys was excyclorotated in V- and Y-pattern exotropia. The PPV of the medial rectus muscle was statistically subnormal by approximately 29% in concomitant, but not pattern, exotropia (P < 0.05). The ratio of the PPV of the LR relative to the MR muscles in concomitant exotropia was significantly greater than in control participants and those with pattern exotropia (P < 0.05). CONCLUSIONS: Abnormalities of EOMs and pulleys contribute differently in pattern versus concomitant exotropia. Abnormal rectus pulley locations derange EOM pulling directions that contribute to pattern exotropia, but in concomitant exotropia, pulley locations are normal, and relatively small medial rectus size reduces relative adducting force.

C596G mutation in FBN1 causes Marfan syndrome with exotropia in a Chinese family.

PURPOSE: To screen mutations in the fibrillin-1 (FBN1) gene in a Chinese family with autosomal dominant Marfan syndrome (MFS). METHODS: Patients and unaffected family members were given ophthalmic, cardiovascular, and physical examinations with a 5-year follow-up. Genomic DNA was extracted from the leukocytes of venous blood from all patients and their relatives. The entire coding region of the FBN1gene was screened with an ABI 9700 GeneAmp PCR System. The mutation identified was screened in 100 healthy and ethnically unrelated Chinese individuals. RESULTS: Mutation screening in FBN1 identified a T>G transition at position c.1786 in exon 14, leading to substitution of cysteine for glycine at codon 596 (C596G) in this four-generation Chinese family. The C596G mutation was associated with the disease phenotypes in all six patients but not found in 14 unaffected family members or the 100 ethnically unrelated and healthy controls. CONCLUSIONS: A C596G mutation in FBN1 was identified in a Chinese family with MFS. Our results expand the spectrum of FBN1 mutations and contribute to the understanding of the role of FBN1 in the pathogenesis of Marfan syndrome.

Cortical metabolic activity matches the pattern of visual suppression in strabismus.

When an eye becomes deviated in early childhood, a person does not experience double vision, although the globes are aimed at different targets. The extra image is prevented from reaching perception in subjects with alternating exotropia by suppression of each eye's peripheral temporal retina. To test the impact of visual suppression on neuronal activity in primary (striate) visual cortex, the pattern of cytochrome oxidase (CO) staining was examined in four macaques raised with exotropia by disinserting the medial rectus muscles shortly following birth. No ocular dominance columns were visible in opercular cortex, where the central visual field is represented, indicating that signals coming from the central retina in each eye were perceived. However, the border strips at the edges of ocular dominance columns appeared pale, reflecting a loss of activity in binocular cells from disruption of fusion. In calcarine cortex, where the peripheral visual field is represented, there were alternating pale and dark bands resembling ocular dominance columns. To interpret the CO staining pattern, [(3)H]proline was injected into the right eye in two monkeys. In the right calcarine cortex, the pale CO columns matched the labeled proline columns of the right eye. In the left calcarine cortex, the pale CO columns overlapped the unlabeled columns of the left eye in the autoradiograph. Therefore, metabolic activity was reduced in the ipsilateral eye's ocular dominance columns which serve peripheral temporal retina, in a fashion consistent with the topographic organization of suppression scotomas in humans with exotropia.

Structural and spontaneous functional brain changes in visual and oculomotor areas identified by functional localization task in intermittent exotropia children.

Intermittent exotropia (IXT) is characterizedby an intermittent outward deviation of the eyes. Yet, the neural substrates associated with IXT are not fully understood. This study investigated brain structure and spontaneous functional activity changes in children with IXT. All participants underwent detailed ophthalmological examinations and multimodal magnetic resonance imaging (MRI) scanning. During functional scanning, binocular visual stimuli were presented to subjects to determine brain areas involved in visual and oculomotor processing. Regions of interest(ROI) were subsequently selected based on functional activation to investigate brain structural and spontaneous functional differences between IXT children and healthy controls (HCs) using small volume correction (SVC). Reduced gray matter density (GMD) was found in the right frontal eye field (FEF) and bilateral inferior parietal lobe (IPL) in IXT children compared with HCs. Besides, reduced fractional amplitude of low-frequency fluctuations (fALFF) values were observed in the left lingual gyrus, right inferior occipital gyrus (IOG), bilateral IPL, and bilateral cerebellum in the IXT children compared to the HCs. IXT children with worse eye position control ability exhibited lower GMD and fALFF values in these areas. Finally, resting state functional connectivity (RSFC) was reduced in frontoparietal oculomotor processing areas in IXT children compared to HCs. In addition, increased cortical thickness was found in the right visual areas and bilateral IPL. These results showed that IXT-related structural and functional brain abnormalities occurred in childhood and may be related to underlying neuropathological mechanisms.

[Study on the changes of fibronectin in the resected medial rectus of patients with concomitant exotropia].

OBJECTIVE: To study the changes of fibronectin in the resected medial rectus muscles in patients with concomitant exotropia and to have a better understanding about the pathomorphological changes of extraocular muscles in the genesis and development of concomitant exotropia. METHODS: Thirty-five concomitant exotropic patients were chosen as exotropic group and 20 normals were selected as control group. In the exotropic group, the age range 2 to 46 years old (mean, 20.9 ys), deviation range -45(Δ) to -90(Δ) (mean, -67.5(Δ)), 19 males, 16 females, and 8 cases have the family history. Exotropic patients were divided into intermittent exotropic group 16 cases and constant exotropic group 19 cases. In the control group, the age range 15 - 28 years old (mean, 18.8 years), 12 males and 8 females. All the resected tissues of the medial rectus muscles were obtained from patients with concomitant exotropia during resection surgery and cornea donators. Fibronectin was measured its mean average optical by Sp method of immunohistochemistry using image analyzer. The amounts of fibronectin in the resected muscle of patients were compared with normals, as well as correlated clinical data of patients such as different types of exotropia, age, degree of deviation, gender and positive family history. RESULTS: The amounts of fibronectin in the resected medial rectus muscle of patients with constant exotropia (0.4729 ± 0.0872) were significantly lower than those of normals (0.5914 ± 0.0547) and intermittent exotropic group (0.5821 ± 0.0792) respectively (q = 7.0314, 6.1177, P < 0.01), while patients with intermittent exotropia did not show significantly lower amounts of fibronectin than those with normals (q = 0.5271, P > 0.05). Neither gender nor positive family was correlated with the amounts of fibronectin (t = 1.1317, 1.6327, P > 0.05) and the amounts of fibronectin had no correlation with age and degree of deviation. CONCLUSION: The amounts of fibronectin were correlated with the course of development of concomitant exotropia. Some of these changes may play a role in the pathogenesis of exotropia from intermittence to constancy, which indicates a further clue to the nature of this disease.

[A family of congenital fibrosis of extraocular muscles associated with naso-sinusitis].

OBJECTIVE: To clinically characterize a collected family of congenital fibrosis of extraocular muscles associated with naso-sinusitis, then determine the genetic location of the disease gene by linkage analysis to approach the etiopathogenesis of CFEOM on gene. METHODS: A CFEOM family (fifteen cases suffering from congenital general fibrosis syndrome in four generations of 41 members) was collected. All the suffers were correlated with clinical ophthalmic and thin-sectioned magnetic resonance imaging across the orbit and the brain-stem level to determine its clinical classification and genetic characteristics. The family was tested for linkage analysis to two known autosomal dominant CFEOM loci on chromosome 12p11. 2-q12 (FEOM1 ) and 16q24 (FEOM3). RESULTS: All the suffers had congenital unilateral or bilateral blepharoptosis, head tilt, chin lift, primary gaze fixed in a hypo-and exotropic position, forced duction testing positive. But vertical and horizontal positions of the eye and restriction of eye movement were different among affected individuals. Furthermore, MRI examinations showed that all the incidence of those families associated with naso-sinusitis and hypertrophic inferior turbinate, and the juveniles with hypertrophic adenoid. Pedigree shows that the family were in line with the characteristics of autosomal dominant inheritance. According to the genetic characteristics and clinical manifestations, the genetic family should be referred as CFEOM3. The lod scores for D12S331, D12S59 and D12S1668 were between 1 and 3, and the maximum lod score was 2. 19 for D12S1048, but the lod scores for D16S520, D16S498 and D16S2621 were both < 1.0. CONCLUSION: This family is best classified as CFEOM3 and linkage with D12S331, D12S59 and D12S1668.

Alterations of lower- and higher-order aberrations after unilateral horizontal rectus muscle surgery in children with intermittent exotropia: A retrospective cross-sectional study.

BACKGROUND: This retrospective, cross-sectional study investigated changes in corneal lower- and higher-order aberrations that cause visual disturbance after lateral rectus recession and medial rectus resection in children. METHODS: Eighty-five eyes of 85 patients (44 boys; 8.64±2.88 years) who underwent lateral rectus recession and medial rectus resection to correct intermittent exotropia were assessed. The Galilei G4 Dual Scheimpflug Analyzer was used for wavefront analysis. Risk factors (age, sex, amount of surgery, preoperative axial length, preoperative intraocular pressure) were determined. Outcome measures included simulated and ray-tracing mode keratometry with secondary defocus, oblique, and vertical astigmatism (for lower-order aberrations) and the root mean square, 3rd-order vertical and horizontal coma, oblique and horizontal trefoil, 4th-order spherical aberration, oblique and vertical secondary astigmatism, and oblique and vertical quadrafoil (2nd‒8th sums) (for higher-order aberrations). RESULTS: Myopic with-the-rule changes in low-order aberrations and increases in simulated and ray-tracing mode keratometry during the 3 months following lateral rectus recession and medial rectus resection were attributed to muscle healing and stability changes. High-order aberrations altered in the week following surgery almost returned to normal within 3 months. Axial length, the amount of surgery, age, and sex affected astigmatism due to differences in patients' scleral states. CONCLUSIONS: Clinicians should consider changes in high-order aberrations of young individuals who underwent lateral rectus recession and medial rectus resection and may not be able to verbalize changes in vision.

Influence of the direction of eye turn on the appearance of strabismus.

PURPOSE: The purpose of this study was to determine whether an equal amount of exotropia (XT) or esotropia (ET) produces a more noticeable eye turn, which gives the better impression of eye contact, and how a positive angle kappa (K) affects this judgment. METHODS: Images from a white male model were manipulated to simulate 0, 5, 10, and 15° of ET and XT for both 0 and +5° K. A series of image pairs was then created that juxtaposed XT and ET of equal angles for both 0 and +5° K. Forty-five optometry students then judged which image in each pair appeared to have the greater tropia and which gave the greater impression of eye contact. RESULTS: When angle kappa was 0, there was no significant difference in whether XT or ET appeared to be more noticeable. However, when angle kappa was +5°, an XT of 5° or greater became more apparent than an equal ET (p < 0.001). However, when the criterion was eye contact, ET gave the greater impression that eye contact was being made when the deviation was 10° or more, and this was true for both 0 and +5° K (p < 0.001). CONCLUSIONS: When a strabismus is to be evaluated or corrected purely for cosmetic reasons, the results may differ depending on the value of angle kappa and whether the criterion for good cosmesis is ocular deviation or eye contact.

[The progress of intermittent exotropia].

Intermittent exotropia is a type of strabismus between exophoria and constant exotropia. The onset age is usually one to four years old. Different from other types of strabismus, intermittent exotropia patient can maintain normal binocular vision in a long period of time. So how to choose the optimal timing and effective treatment is a challenge for clinicians. The objective of this article is to review the recent research progress of intermittent exotropia, including the severity classification, non-surgical treatment, timing of surgery and surgical methods, overcorrection and under correction treatment etc., and give some recommendations for the treatment of intermittent exotropia.

Effects of prolonged use of virtual reality smartphone-based head-mounted display on visual parameters: a randomised controlled trial.

We investigated the effects of using a virtual reality smartphone-based head-mounted display (VR SHMD) device for 2 h on visual parameters. Fifty-eight healthy volunteers were recruited. The participants played games using VR SHMD or smartphones for 2 h on different days. Visual parameters including refraction, accommodation, convergence, stereopsis, and ocular alignment and measured choroidal thickness before and after the use of VR SHMD or smartphones were investigated. Subjective symptoms were assessed using questionnaires. We analyzed the differences in visual parameters before and after the use of VR SHMD or smartphones and correlations between baseline visual parameters and those after the use of the devices. Significant changes were observed in near-point convergence and accommodation, exophoric deviation, stereopsis, and accommodative lag after the use of VR SHMD but not after that of smartphones. The subjective discomfort associated with dry eye and neurologic symptoms were more severe in the VR group than in the smartphone group. There were no significant changes in refraction and choroidal thickness after the use of either of the two devices. The poorer the participants' accommodation and convergence ability the greater the resistance to changes in these visual parameters, and participants with a large exophoria were more prone to worsening of exophoria than those with a small exophoria.

Prevalence of strabismus and its risk factors among school aged children: The Hong Kong Children Eye Study.

The study aims to determine the prevalence of strabismus and its risk factors among school children in Hong Kong. This is a cross-sectional study involving 6-8 year old children from different districts in Hong Kong. 4273 children received comprehensive ophthalmological examination, cycloplegic auto-refraction, best corrected visual acuity (BCVA), anterior segment examination, cover/uncover test, ocular motility, and fundus examination. Demographic information, pre- and post- natal background, parental smoking status, and family history of strabismus were obtained through questionnaires. Strabismus was found among 133 children (3.11%, 95% CI 2.59-3.63%), including 117 (2.74%) exotropia and 12 (0.28%) esotropia cases (exotropia-esotropia ratio: 9.75:1). There was no significant difference in prevalence across age (6-8 years) and gender. Multivariate analysis revealed associations of strabismus with myopia (≤ - 1.00D; OR 1.61; 95% CI 1.03-2.52; P = 0.037) hyperopia (≥ + 2.00D; OR 2.49; 95% CI 1.42-4.39; P = 0.002), astigmatism (≥ + 2.00D; OR 2.32; 95% CI 1.36-3.94; P = 0.002), and anisometropia (≥ 2.00D; OR 3.21; 95% CI 1.36-7.55; P = 0.008). Other risk factors for strabismus included maternal smoking during pregnancy (OR 4.21; 95% CI 1.80-9.81; P = 0.001), family history of strabismus (OR 6.36; 95% CI 2.78-14.50, P < 0.0001) and advanced maternal age at childbirth (> 35 years; OR 1.65; CI 1.09-2.49, P = 0.018). The prevalence of strabismus among children aged 6-8 years in Hong Kong is 3.11%. Refractive errors, family history of strabismus and maternal smoking history during pregnancy are risk factors. Early correction of refractive errors and avoidance of maternal smoking during pregnancy are potentially helpful in preventing strabismus.

[Dynamic nuclear magnetic resonance in strabismus]. / Rezonanta magnetica nucleara dinamic în evaluarea pacientului cu strabism.

PURPOSE: To demonstrate that dynamic MRI is a useful tool in complex strabismus patients. SUBJECTS AND METHODS: 16 patients were referred to us with suspicion of slipped or '"lost" medial rectus (MR), 15 after strabismus surgery. 1 case with lost MR after trauma. One patient had "A" pattern exotropia with over depression in adduction. 8 underwent dynamic MRI examination. RESULTS: The dynamic MRI showed the precise muscle location and the contractility of the muscle. All patients underwent surgery, according to deviation and ocular motility changes. All slipped muscles were found and re-attached to the globe. In the "A" pattern exotropia MRI showed superior displacement of the LR pulleys. The inferior rectus did not demonstrate contractility and a transfer procedure was made. CONCLUSIONS: MRI is an index of functional muscle contractility and precise muscle location. It should be considered in complex cases of strabismus as an important argument in choosing the surgical technique.

Consanguineous-derived homozygous WNT1 mutation results in osteogenesis imperfect with congenital ptosis and exotropia.

BACKGROUND: Wnt signaling pathway plays an important role in promoting ostergenesis. WNT1 mutations have been considered as a major cause of ostergenesis imperfect (OI). We identified an OI patient with pathogenic consanguineous-derived homozygous WNT1 missense mutation. METHODS: We designed and applied a panel of known 261 genes associated with hereditary bone diseases for targeted next-generation sequencing to examine clinically diagnosed OI patients. Detected mutations were confirmed by Sanger sequencing. RESULTS: The female proband presented with severe OI with low bone density, multiple long bone fractures, short stature, and absence of dentinogenesis imperfect and brain malformation. She had congenital ptosis and exotropia with her left eye, and absence of blue sclera. The proband came from a consanguineous family and had a homozygous WNT1 missense mutation (c.677C>T, (p.S226L)). In addition, three other compound heterozygous mutations (c.1729C>T in FKBP10, c.1958A>C in FGFR3, c.760G>C in TRPV4) were also detected in her family members. CONCLUSION: We report the first identified case of consanguineous derived homozygous WNT1 mutation leading to severe osteogenesis imperfecta with congenital ptosis and exotropia.

Increased myofiber size and reduced satellite cell numbers in medial rectus muscle of patients with intermittent exotropia.

PURPOSE: To elucidate the differences in muscle bundle and satellite cells in medial rectus muscle through histological and Immunofluorescence studies of intermittent exotropia patients and normal controls. Materials and Methods: From January 2015 to December 2017, 15 patients who underwent medial rectus resection surgery at Kosin University Gospel Hospital were enrolled. Four medial recti muscles collected from two brain-dead men without strabismus were used as controls and compared with the intermittent exotropia group. Hematoxylin and eosin (HE) staining were performed, and all muscle bundle diameters were measured with the Image J program and compared to the mean value. Immunological staining for MyoHC (Myosin Heavy Chain), PAX7 (Transcription Factor), and PCNA (Proliferating Cell Nuclear Antigen) were performed to analyze the distribution of myocytes and PAX7-positive and PCNA-positive cells. Results: The mean ages of the strabismus and control groups were 17.33 ± 13.05 and 22.0 ± 5.85 years, respectively, and the male to female ratio was 7:2 and 2:0. The average angle of deviation in the exotropia patients was 36.0 ± 16.83 prism diopters. The mean muscle bundle diameter under light microscopy was 60.21 ± 1.48 in the exotropia group and 52.27 ± 0.74 in the control group. The exotropia group showed significantly greater mean muscle bundle diameter (p < .001) and diameter regularity than the control group. The PAX7(+)/muscle bundle number ratio was 0.016 ± 0.014 and 0.056 ± 0.015 in the exotropia group and control group, respectively (p < .001), and the PCNA(+)/muscular bundle number ratio was 0.015 ± 0.017 and 0.182 ± 0.102 (p < .001). Both were significantly higher in the control group compared to that in the exotropia patients. Conclusion: In the exotropia group, mean diameter of medial rectus muscle bundle was significantly larger than that of control group. The ratios of PAX7 and PCNA to muscle bundle number were significantly higher in the control group than intermittent extropia group. We found the negative relationship between activation of satellite cells and muscle bundle diameter, and it might take one step forward to elucidate the pathogenesis of intermittent extropia.

Analysis of astigmatism outcomes after horizontal rectus muscle surgery in patients with intermittent exotropia.

This study examined the factors affecting corneal curvature change after lateral rectus recession and medial rectus resection surgery in patients with intermittent exotropia. This was a retrospective cross-sectional study in intermittent exotropia patients who underwent rectus resection surgery. The study involved 41 male and 42 female patients (mean age: 9.55 ± 5.03 years, range: 3-28 years). Corneal astigmatism analysis was performed using the Galilei G4 Dual Scheimpflug Analyzer. The values of simulated and ray tracing corneal keratometry (K) of astigmatism, including axis changes, were determined preoperatively and at 1 week and 3 months postoperatively. The factors found to affect corneal curvature change were sex, extent of surgery, and axial length. Simulated and ray tracing changes were significant preoperatively and at 1 week and 3 months after rectus resection surgery (p < 0.05); however, there were no differences in astigmatism (D) at any time. The spherical equivalent had a myopic change after rectus resection surgery with cycloplegic refraction, and in ray tracing mode, flat K was decreased at 1 week from baseline and increased 3 months later. Steep, mean K, and axis increased continuously from baseline to 1 week and 3 months. Astigmatism, in contrast, was increased at 1 week, but decreased at 3 months, with no return to baseline. Univariable linear regression analyses showed that the extent of surgery had an effect on flat K change and that sex had an effect on steep K and axis. Additionally, axial length affected steep K and astigmatism, while age had no effect on any variable. Ray tracing values were significantly different from simulated values. In ray tracing mode, rectus resection surgery may result in astigmatism shifted toward with-the-rule, and myopic changes may be caused by differences in thickness and flexibility of the sclera. Notably, age did not affect any variable.

Surgical outcomes of intermittent exotropia according to exotropia type based on distance/near differences.

We compare the surgical outcomes of intermittent exotropia of the basic, pseudo-divergence excess (pseudo-DE) and true divergence excess (true DE) types. A study was performed with 342 patients who had undergone surgery for intermittent exotropia of the basic, pseudo-DE or true DE type with a postoperative follow-up period of 6 months or more. The main outcome measures were postoperative angles of deviation at distance and near, and surgical success rates. Surgical success was defined as alignment between exodeviation of 10 PD and esodeviation of 5 PD at distance and near. Additionally, survival curves of recurrence were analyzed by the Kaplan-Meier method. The postoperative angles of deviation at both distance and near in pseudo-DE type were significantly smaller than those in basic type at the final examination (p = 0.003, <0.001). The final surgical success rate in pseudo-DE (70.2%) was better than in basic (46.3%) or true DE (28.6%) (p = 0.003, 0.01). Reoperation for recurrent exotropia was performed in 27% of the basic, 17% of the pseudo-DE, and 35.7% of the true DE cases. According to a survival analysis for recurrence, patients with pseudo-DE showed lower incidence of recurrence than did patients with basic and true DE (p = 0.003, 0.02). In conclusion, the patients with intermittent exotropia of the pseudo-DE type showed better surgical outcomes than those with the basic or true DE type. Pseudo-DE also showed a lower recurrence rate than did the other 2 groups.

Quantitative measurement of horizontal strabismus with digital photography.

PURPOSE: To develop a method to calculate the gaze angle in photographs and to determine its validity and reliability in real strabismus patients. METHODS: Photographs of eyes from 15 orthophoric subjects (n = 1,022) with known gaze angle and imaging distance were investigated with the help of a smartphone application developed by the authors. The application provided measurements of the distance from the geometrical center of the cornea to the light reflex (RD) and corneal diameter (CD). The RD/CD ratio of each gaze angle was recorded. To estimate the eyes' gaze angle, an equation to determine the best-fit line for the gaze angle data according to each RD/CD ratio was created. In a second clinical analysis, this equation was applied to photographs of real strabismus patients (n = 72), and the results were compared with measurements taken by a double-masked strabismus specialist. Separately, an equation was created to calculate the imaging distance using the given interpupillary distance. RESULTS: There was a high correlation between the real and estimated gaze angles (r = 0.990, P < 0.001). The mean error of the estimated gaze angle was found to be 0.03Δ ± 4.60Δ. There was a high correlation between the real and estimated imaging distance (r = 0.997, P < 0.001) and a high correlation between the measurements of the application and the specialist (r = 0.966, P < 0.001). The average error was -0.68 Δ ± 6.1Δ, and the reliability was high (Cronbach's α = 0.983). CONCLUSIONS: The application measured horizontal strabismus in photographs with high reliability.

Orbital heterotopic glial tissue presenting as exotropia.

A 5-month-old female infant was noted to have difficulty in fixating with the left eye with accompanying progressive exo-deviation and axial proptosis. She also had optic disc hypoplasia with the double ring sign. Computed tomography showed left superomedial orbital mass without any orbital bony defect. Incisional biopsy through a medial orbitotomy allowed significant reduction in tumor burden except for the most apical portion. The affected eye resumed normal alignment and full motility. Histopathologically, the tumor was composed of glial tissue intermixed with muscle fibers. Immunohistochemically, desmin and glial fibrillary acidic protein were strongly expressed. Minimal proptosis of the left eye heralded the recurrence of the tumor 4 years later, also confirmed by magnetic resonance imaging studies. This patient embodies the rare occurrence of isolated heterotopic glial tissue in the orbit with skeletal muscle as one of its components and optic disc hypoplasia as the associated ocular anomaly. Late recurrence may occur following incomplete tumor removal.