Allele-specific antisense oligonucleotides for the treatment of BEST1-related dominantly inherited retinal diseases: An in vitro model.

Retinal dystrophies are a common health problem worldwide that are currently incurable due to the inability of retinal cells to regenerate. Inherited retinal diseases (IRDs) are a diverse group of disorders characterized by progressive vision loss caused by photoreceptor cell dysfunction. The eye has always been an attractive organ for the development of novel therapies due to its independent access to the systemic pathway. Moreover, anti-sense oligonucleotides (ASOs), which facilitate manipulation of unwanted mRNAs via degradation or splicing, are undergoing rapid development and have been clinically deployed for the treatment of several diseases. The primary aim of this study was to establish a reliable in vitro model utilizing induced photoreceptor-like cells (PRCs) for assessing the efficacy and safety of ASOs targeting the BEST1 gene. Despite advances in gene therapy, effective treatments for a broad range of IRDs remain limited. An additional aim was to develop an in vitro model for evaluating RNA-based therapeutics, specifically ASOs, for the treatment in IRDs. Firstly, a cell culture model was established by induction of PRCs from dermal fibroblasts via direct programming. The induced PRCs were characterized at both the transcriptomic and protein level. Then, a common single nucleotide polymorphism (SNP) was identified in the BEST1 gene (rs1800007) for targeting with ASOs. ASOs were designed using the GapmeR strategy to target multiple alleles of this SNP, which is potentially suitable for a large proportion of the population. The efficacy and possible off-target effects of these ASOs were also analyzed in the induced PRC model. The findings show that the selected ASOs achieved allele-specific mRNA degradation with virtually no off-target effects on the global transcriptome profile, indicating their potential as safe and effective therapeutic agents. The presented in vitro model is a valuable platform for testing personalized IRD treatments and should inspire further research on RNA-based therapeutics. To the best of our knowledge this study is the first to test RNA-based therapeutics involving the use of ASOs in an induced PRC model. Based on the present findings, it will be possible to establish an ex vivo disease model using dermal fibroblast samples from affected individuals. In other words, the disease model and the ASOs that were successfully designed in this study can serve as a useful platform for the testing of personalized treatments for IRDs.

Is the Pupil Involved in Duane Syndrome? Static and Dynamic Pupillometry Characteristics.

Objectives: Duane syndrome (DS) is typically characterized by abduction and/or adduction deficiency accompanied by eyelid and ocular motility disturbances. Maldevelopment or absence of the sixth nerve has been shown to be the causative factor. The aim of the present study was to investigate static and dynamic pupillary characteristics in patients with DS and compare the results with those of healthy eyes. Materials and Methods: Patients with unilateral isolated DS and no history of ocular surgery were enrolled in the study. Healthy subjects with a best corrected visual acuity (BCVA) of 1.0 or higher were assigned to the control group. All subjects underwent complete ophthalmological examination and pupillometry measurements (MonPack One, Vision Monitor System, Metrovision, Perenchies, France) including static and dynamic pupil evaluation. Results: A total of 74 patients (22 with DS and 52 healthy subjects) were included in the study. The mean age of the DS patients and healthy subjects was 11.05±5.19 and 12.54±4.05 years, respectively (p=0.188). There was no difference in sex distribution (p=0.502). Mean BCVA differed significantly between eyes with DS and healthy eyes, and between healthy eyes and the fellow eyes of DS patients (p<0.05). No significant difference was found in any static or dynamic pupillometry parameters (p>0.05 for all). Conclusion: In the light of the results of the present study, the pupil seems to be not involved in DS. Larger studies including more patients with different types of DS in different age groups or comprising patients with non-isolated DS may reveal different findings.

How to Manage a Strabismus Clinic During the COVID-19 Pandemic; What is Really Urgent, What is Not?: A Single-Center Case Series from Turkey

Objectives: To evaluate the management of the pediatric ophthalmology and strabismus clinic when strict quarantine conditions were adopted during the coronavirus disease 2019 (COVID-19) pandemic in Turkey. Materials and Methods: The study presents a review of the patients examined during the quarantine period. All patients were assessed with the highest possible level of personal protection. Results: Ten patients (6 girls, 4 boys) with a mean age of 9 years (range: 2-16) were evaluated. The patients presented 3-20 days after symptom onset. Ocular misalignment and diplopia were the main symptoms. Four of the 10 patients were diagnosed with sixth cranial nerve palsy and three patients were diagnosed with acute-onset comitant esotropia. Six patients had significant cranial magnetic resonance imaging findings. Conclusion: Acute-onset neurological conditions are more common during the COVID-19 pandemic. These reports will contribute to global experience and understanding of COVID-19.

Management of cataracts secondary to intravitreal chemotherapy injections for retinoblastoma seeding.

PURPOSE: To report our experience in the management of cataracts presumably due to intravitreal chemotherapy administration in eyes with vitreous disease associated with retinoblastoma. METHODS: This retrospective study consisted of a cohort of five eyes of five retinoblastoma patients who developed cataracts secondary to intravitreal chemotherapy administration and who then underwent cataract surgery. All patients underwent lensectomy and anterior vitrectomy with/without intraocular lens implantation via clear corneal approach. All cases were administered intraoperative intravitreal melphalan (35-40 mcg) and topotecan (10-20 mcg) at the end of cataract surgery as a preventive measure against retinoblastoma spread. Injections were repeated as needed in monthly follow-ups. Main outcome measures were enucleation rate and disease-free survival time. RESULTS: The age at surgery ranged between 5 and 10 years. Follow-up time varied from 12 to 16 months. Treatment-free period before surgery ranged between 3 and 20 months. Time from last injection to cataract detection was: 2, 2, 10, 6, and 7 months; and time from last injection to cataract surgery was: 8, 3, 20, 7, and 15 months in cases 1-5, respectively. None of the eyes required enucleation. Tumor control was achieved in all patients at the end of follow-up. CONCLUSIONS: Injection of melphalan and topotecan into anterior parts of the vitreous may lead to cataract formation. This can be safely managed with lensectomy and anterior vitrectomy and the use of intravitreal administration of melphalan and topotecan at the conclusion of the surgery as a precautionary measure against the potential risk of extraocular spread.

Is Fixation Preference a Potential Indicator of Macular Function in Children?

Objectives: Fixation preference testing is widely used to detect amblyopia, particularly in preverbal children. Pattern electroretinogram (pERG) is an electrophysiological test which is a sensitive indicator of macular function. The aim of this study was to investigate the relationship between fixation preference and macular function on pERG in children with strabismus. Materials and Methods: The study included 11 children with strabismus. All underwent ophthalmological examination including fixation preference by binocular fixation pattern test, best corrected visual acuity (BCVA) assessment, and pERG. Results: The mean age of the patients was 10.09±1.18 years. All patients had unilateral fixation. The mean BCVA was 0.85±0.17 in preferred and 0.48±0.19 in non-preferred eyes (p=0.003). The mean p50 amplitude was 6.07±2.06 µV in preferred and 5.29±2.20 µV in non-preferred eyes (p=0.203), and the mean N95 amplitude was 8.27±2.86 µV and 8.03±3.24 µV respectively (p=0.594). BCVA was correlated with p50 and N95 amplitudes in the non-preferred eyes (p=0.023 and p=0.014). Interocular BCVA difference was correlated with interocular P50 amplitude difference (r=0.688, p=0.019). Conclusion: Although amblyopia is typically considered a cortical phenomenon, future larger studies are needed to investigate the relationship between fixation preference and macular electrophysiological function.

Clinical and Radiological Findings in Patients with Newly Diagnosed Graves' Ophthalmopathy.

BACKGROUND: Graves' ophthalmopathy is the most common extrathyroidal manifestation of Graves' disease. The objective of this study was to investigate the clinical ophthalmological and MRI findings in newly diagnosed Graves' ophthalmopathy. METHODS: This study included 36 newly diagnosed Graves' disease patients and 23 control participants. Patients and control participants underwent detailed ophthalmologic examination. In addition, all subjects underwent orbital MRI examination; and sizes, cross-sectional areas, and signal intensities of extraocular muscles were also measured. RESULTS: Based on MRI measurements, the mean exophthalmos in the left eye was significantly higher in the patient group when compared to those of controls (2.04 ± 0.29 vs. 1.85 ± 0.15 cm, p = 0.003). The mean long diameter of inferior oblique muscle in both the right and left eyes were significantly shorter in patients when compared to those of controls (p = 0.001, p = 0.002, resp.); however, the mean long diameter of superior oblique in the left eye was longer in patients than those of controls (p = 0.001). Patients had significantly higher superior oblique muscle signal intensity than those of controls in the right eye (p = 0.01). There was no significant difference for the other parameters between the patient and control groups. CONCLUSION: Our findings suggest that there is no obvious change in MRI examination despite clinical ophthalmological findings in patients with newly diagnosed Graves' ophthalmopathy. Unnecessary MRI examination should be avoided in this patient group due to unsatisfactory cost-effectiveness.

Congenital Cataract and Its Genetics: The Era of Next-Generation Sequencing

Congenital cataract is a challenging ophthalmological disorder which can cause severe visual loss. It can be diagnosed at birth or during the first year of life. Early diagnosis and treatment are crucial for the visual prognosis. It can be associated with various ocular and systemic abnormalities. Determining whether congenital cataract is isolated or associated with other pathology is an indispensable step for the prediction of potential vision as well as early diagnosis and treatment of conditions that can cause morbidity or mortality. Many genes have been identified in the molecular etiology of congenital cataract. Most mutations have been reported in the crystallin genes. Determination of the genetic cause may not only enable individualized genetic counseling but also help to identify concomitant ocular and/or systemic disorders depending on the characteristics of the genetic test used. Recently, next-generation sequencing in particular has become an evolving technology for determining the molecular etiology of congenital cataract and furthering our knowledge of the disease.

Histopathological features and satellite cell population characteristics in human inferior oblique muscle biopsies: clinicopathological correlation.

PURPOSE: To investigate the correlation between clinical characteristics and histopathological and immunohistochemical features of inferior oblique muscles in patients with primary and secondary inferior oblique overaction. METHODS: Inferior oblique muscle specimens of patients who underwent inferior oblique-weakening procedures for primary or secondary inferior oblique overaction were recruited. Subjects were mainly divided into two groups, each of which was further divided into two subgroups: group 1 included patients with primary inferior oblique overaction (subgroups, infantile esotropia vs acquired V-pattern esotropia), and group 2 included patients with secondary inferior oblique overaction (subgroups, congenital vs acquired trochlear nerve palsy). Inferior oblique overaction was graded between 0-4. Histopathologic changes, such as angular fibers, endo- and perimysial fibrosis, and vacuolization were categorized from mild to severe. Immunohistochemical markers Pax7, NCAM, and MyoD1 were used to detect satellite cells, a unique stem cell population in muscles presumably responsible from myofiber regeneration and maintenance, and their activity. Results were reported as stained cells per cross-section ratio. RESULTS: A total of 51 patients were included: 36 in group 1 and 15 in group 2. Satellite cell distribution and activity was significantly higher in group 1 (P < 0.001). The angular fiber count and the degree of perimysial fibrosis was higher in the secondary group (P < 0.001 and P = 0.01, resp.). There was no correlation between clinical amount of inferior oblique muscle overaction and immunohistochemical markers. CONCLUSIONS: The differences in immunohistochemical parameters supported with histopathological changes between different strabismus etiologies imply that satellite cell population behavior varies among strabismus types.

Molecular Etiology of Isolated Congenital Cataract Using Next-Generation Sequencing: Single Center Exome Sequencing Data from Turkey.

Congenital cataract, which refers to lenticular opacity diagnosed at birth or more commonly during the first year of life, is one of the leading causes of childhood blindness. Molecular understanding of the disease pathogenesis has evolved thanks to many studies based on modern technologies. In this study, we aimed to identify and discuss the molecular etiology of nonsyndromic or nonmetabolic bilateral congenital cataract by whole-exome sequencing (WES). Patients with bilateral congenital cataract presumed to be isolated after metabolic and genetic evaluation were enrolled in the study. All patients underwent detailed ophthalmological examination and bilateral cataract surgery. DNA samples of the probands, parents, and available affected family members were analyzed by WES. Variants were validated and confirmed by Sanger sequencing in all probands and in available affected family members. A total of 4 patients (3 girls and 1 boy) were recruited. Two patients had nuclear, 1 patient had total, and 1 patient had combined lamellar and sutural cataract. One family had consanguinity. A heterozygous c.215+1G>A mutation in CRYBA1, heterozygous c.432C>G (p.Tyr144Ter) mutation in CRYGC, heterozygous c.70A>C (p.Pro24Thr) mutation in CRYGD, and a heterozygous c.466G>A (p.Gly156Arg) mutation in CRYBB3 were detected. All these mutations were confirmed by Sanger sequencing in selected affected individuals. The current study identified all causative mutations of congenital cataract in the crystalline genes. The results confirmed that WES is a very useful tool in the investigation of the diseases with heterogeneous genetic background.

Is macular pigment optical density really involved in fixation preference?

PURPOSE: To evaluate macular pigment optical density in healthy children and to compare the values with those of strabismic children with respect to fixation preference. METHODS: The study recruited 54 healthy and 41 strabismic children. Two groups were matched in terms of gestational age, birth weight, and body mass index. All participants underwent complete ophthalmological evaluation and macular pigment optical density measurement and filled a self-reported food frequency questionnaire. Strabismic children were categorized according to fixation preference. RESULTS: The mean age was 9.87 ± 2.39 years in healthy children and 9.07 ± 2.07 years in children with strabismus (p = 0.091). Mean macular pigment optical density was 0.23 ± 0.25 in healthy eyes and 0.25 ± 0.27 in non-preferred eyes of strabismic children (p = 0.964). Macular pigment optical density was significantly higher in preferred eyes of strabismic children (0.43 ± 0.34) compared to non-preferred eyes (p = 0.004) and healthy eyes (p = 0.001). There was a difference of macular pigment optical density between both eyes in patients with grades 1, 2, and 3 fixation preference, whereas patients with grade 4 preference had similar macular pigment optical density in both eyes (p = 0.008). There was a statistically significant positive correlation between macular pigment optical density in preferred eyes and body mass index (r = 0.354, p = 0.023). CONCLUSION: Preferred eyes of children with strabismus seem to have higher macular pigment optical density readings. This difference may emerge from the higher tendency of recognizing the flicker stimulus while preferred eye is under testing. Similar macular pigment optical density in healthy and non-preferred eyes and the fact that both lower than preferred eyes remain unexplained. It should be kept in mind that macular pigment optical density results should be carefully interpreted and macular pigment optical density in cases with strabismus should be further investigated.

Are we overlooking masked bilateral congenital superior oblique palsy in children: is it possible to diagnose before surgery?

PURPOSE: To describe the characteristics of children who had subsequent contralateral superior oblique underaction (SOUA) and inferior oblique overaction (IOOA) after unilateral inferior oblique weakening surgery and to identify suggestive clinical features for masked bilateral fourth nerve palsy. METHODS: The medical records of children who underwent unilateral inferior oblique tenotomy as a single procedure for unilateral superior oblique palsy were all reviewed. Diagnosis was based on evaluation of ocular misalignment in nine diagnostic gaze positions and presence of SOUA, IOOA, and abnormal head position. RESULTS: The study was conducted with 29 children. All children had preoperative unilateral IOOA and SOUA. Eleven children (37.9%) had hyperesodeviation in the affected eye, while others (62.1%) had hyperexodeviation. The mean age at surgery was 6.66 ± 1.87 (4-10) years. The mean vertical deviation, exodeviation, and the amount of IOOA were decreased postoperatively (p < 0.001 for all). Among the 29 children, 22 had no residual ipsilateral IOOA, 2 had ipsilateral IOOA, and 5 had ipsilateral inferior oblique underaction (IOUA) at last visit. Three children had contralateral SOUA, IOOA, and hyperdeviation at follow-up visits, one of whom had IOUA on the operated eye. There was no difference of preoperative features between children with or without subsequent contralateral superior oblique palsy. CONCLUSION: Bilateral congenital superior oblique palsy may be overlooked in children in spite of detailed preoperative evaluation. Masked bilaterality should always be kept in mind in cases with unilateral pathology. Patients should be informed about the possibility of bilaterality.

Bilateral optic disc pathologies as an accompanying feature of comitant strabismus in children.

PURPOSE: To describe and report accompanying bilateral optic disc pathologies in children with comitant strabismus. METHODS: Twenty-eight patients (16 female, 12 male) aged between 1 and 12 years who had comitant strabismus and bilateral optic disc pathologies were included in the study. Visual acuity, refractive errors, amount of deviation and types of optic disc pathologies were all recorded. Each patient underwent complete neurological and ophthalmological examination. RESULTS: Of the 28 patients, 14 (50.0%) had esotropia and 14 (50.0%) had exotropia. The mean age was 4.18 ± 3.03 years. The mean deviation angle was 35.30 ± 13.26 prism diopters (PD) (20-70 PD). Optic atrophy as being the most common pathology was found in nine (32.1%) patients. Six (21.4%) patients had temporal disc pallor, six (21.4%) patients had optic nerve hypoplasia, and seven (25%) patients had other optic disc anomalies (tilted disc, megalodisc, disc coloboma, peripapillary staphyloma). Optic disc pathologies were found to be isolated in 12 patients. Nine of 13 patients with congenital optic disc pathologies had esotropia, whereas 10 of 15 patients with optic atrophy or optic disc pallor had exotropia. CONCLUSION: Comitant strabismus in children can be associated with congenital or acquired optic disc pathologies. It is worthy of note that esotropia was more common in patients with congenital optic disc pathologies, whereas exotropia was more frequent in patients with optic atrophy or optic disc pallor. The findings of the present study show that complete ophthalmological examination including fundus evaluation should be carried out in all patients with strabismus even though the cause of ocular misalignment is obvious.

Homozygous indel mutation in CDH11 as the probable cause of Elsahy-Waters syndrome.

Two sisters from a consanguineous couple were seen in genetics department for facial dysmorphic features and glaucoma. They both had broad foreheads, hypertelorism, megalocorneas, thick eyebrows with synophrys, flat malar regions, broad and bulbous noses, and mild prognathism. Both had glaucoma, younger one also had cataracts and phthisis bulbi. Other findings included bilateral partial cutaneous syndactyly of 2nd and 3rd fingers, history of impacted teeth with dentigerous cyst in the elder one, and intellectual disability (mild and borderline). The sisters were considered to have Elsahy-Waters syndrome. In order to elucidate the underlying molecular cause, sisters and their healthy parents were genotyped by SNP arrays, followed by homozygosity mapping. Homozygous regions were further analyzed by exome sequencing in one affected individual. A homozygous indel variant segregating with the condition was detected in CDH11 (c.1116_1117delinsGATCATCAG, p.(Ile372MetfsTer9)), which was then validated by using Sanger sequencing. CDH11 encodes cadherin 11 (osteo-cadherin) that regulates cell-cell adhesion, cell polarization and migration, as well as osteogenic differentiation. Further experiments revealed that CDH11 expression was decreased in patient-derived fibroblasts as compared to the heterozygous parent and another healthy donor. Immunostaining showed absence of the protein expression in patient fibroblasts. In addition, cell proliferation rate was slow and osteogenic differentiation potential was delayed. We consider that this study reveals loss-of-function mutations in CDH11 as a probable cause of this phenotype. Next generation sequencing in further patients would both prove this gene as causative, and finely delineate this clinical spectrum further contributing in identification of other possibly involved gene(s).

Ocular Causes of Abnormal Head Position: Strabismus Clinic Data.

OBJECTIVES: To determine the most common ocular causes and types of abnormal head position (AHP) and describe their clinical features. MATERIALS AND METHODS: Patients with AHP who had been followed in the strabismus unit were retrospectively reviewed. Demographic features and orthoptic characteristics were recorded. RESULTS: A total of 163 patients including 61 women (37.4%) and 102 men (62.6%), with a mean age of 19.9±18.3 were recruited. The most common causes of AHP were determined as fourth cranial nerve palsy (33.7%), Duane retraction syndrome (21.5%), sixth cranial nerve palsy (11%), nystagmus blockage syndrome (9.8%) and Brown syndrome (6.7%). Other less frequent causes were A-V pattern strabismus, comitant strabismus, thyroid orbitopathy and third cranial nerve palsy. The most common types of AHP were head tilt (45.4%) and face turn (36.8%). Out of 142 patients whose visual acuity could be evaluated, 28.2% had amblyopia. The frequency of amblyopia varied depending on the diagnosis (p<0.001), while there was no relation between amblyopia and different types of AHP (p=0.497). Stereopsis and fusion could be tested in 128 patients and 43.8% of them had stereopsis and fusion. The presence of stereopsis and fusion was found to be related with the diagnosis (p=0.001), whereas it was not related with the types of AHP (p=0.580). The presence of amblyopia was not significantly associated with fusion (p=1.000) or stereopsis (p=0.602). CONCLUSION: There are many ocular pathologies that cause AHP. Patients with similar diagnoses may have different types of AHP. Patients may have amblyopia and impaired binocularity despite AHP. Therefore, all patients with AHP should be examined in detail and these points should be considered in the treatment plan.

The frequency and causes of abnormal head position based on an ophthalmology clinic's findings: is it overlooked?

PURPOSE: To determine the frequency of abnormal head position (AHP) and identify the underlying causes in patients who presented to an ophthalmology clinic due to any ophthalmologic complaint. METHODS: The medical records of patients who presented with any ophthalmologic symptoms during a 6-month period were prospectively evaluated. In all, 2,710 patients (1,492 female and 1,218 male) aged 6 months-91 years were included in the study. Each patient underwent complete ophthalmologic evaluation. RESULTS: Among the 2,710 patients, 30 (1.1%) (7 female and 23 male) with a mean age of 14.62 ± 17.45 years (range 6 months-60 years) had AHP. In total, 24 (80%) of the patients with AHP were aged ≤16 years. The initial complaint in the patients with AHP was ocular misalignment in 18 (60%) patients, AHP in 4 (13.3%), abnormal ocular movements in 4 (13.3%), double vision in 3 (10%), and droopy eyelid in 1 (3.3%). Comitant strabismus, nystagmus, and Duane syndrome were the most common causes of AHP. Other diagnoses included fourth nerve palsy, sixth nerve palsy, Brown syndrome, congenital muscular torticollis, ptosis, and blowout orbital fracture. CONCLUSIONS: The leading underlying causes of AHP in patients who presented to an ophthalmology clinic were ocular and treatable. Of note, in only a minority of these patients AHP was the initial presenting complaint. Clinicians must be aware that observation of any head position that is not normal should prompt additional investigation, as the underlying pathology can cause treatable morbidity or in rare instances mortality, such as in cases of acute cranial nerve palsy.

Reliability and interexaminer agreement for induced tropia test: is normal always normal?

The purpose of this study was to evaluate the reliability of the fixation preference testing with 10 and 20 diopter prisms (Δ) in children without strabismus in order to extrapolate its utility to preverbal children and to determine interexaminer agreement. Fourty children (24 girls, 16 boys) aged between 5 and 16 years with normal ophthalmological examination except refractive errors were included in the study. The visual acuity, refractive errors, and orthoptic findings were recorded. The base-down prism fixation test was performed by two experienced examiners with 10Δ and 20Δ. The presence of corrective movement was recorded as positive result separately for each eye. Best-corrected visual acuity was 1.0 bilaterally for all patients. All patients had binocular single vision and stereopsis. First examiner noted bilateral fixation movement in 65 % patients with 10Δ and in 57.5 % with 20Δ, second examiner in 50 % with 10Δ, and in 37.5 % with 20Δ. Interexaminer agreement was 42.5 % for 10Δ and 54.5 % for 20Δ (p < 0.01). Both examiners observed the fixation movement to be less frequent in older children. The fixation movement can be absent or seen asymmetrically even in children with equal visual acuity and binocular vision. The rate of fixation movement seemed to be reduced with age possibly due to increased concentration and cooperation of the child. In addition, there was a remarkable interexaminer variability in both tests. It should be borne in mind that the findings of prism-guided fixation preference tests may be misleading in preverbal children.

Fixation preference test: reliability for the detection of amblyopia in patients with strabismus and interexaminer agreement.

PURPOSE: The purpose of this study was to analyze the reliability of the fixation preference test (FPT) in the detection of amblyopia, and to determine interexaminer agreement. METHODS: Eighty patients whose visual acuity could be tested objectively and had a horizontal misalignment of more than 10 prism diopters were enrolled. The best corrected visual acuity (BCVA) and orthoptic findings were all recorded. Non-preferred eye in primary position and fixation preference grade were assessed independently by two masked experienced examiners. The primary outcome measures were reliability of FPT in terms of its correlation with BCVA and interexaminer agreement. RESULTS: There was no significant correlation between fixation preference grades and interocular visual acuity difference as well as the type and amount of deviation, the presence of fusion, stereopsis, anisometropia, and previous strabismus surgery for none of the examiners (p > 0.05 for all). Sensitivity was 52.0% for examiner 1 and 54.0% for examiner 2 while specificity was 50.0 and 46.7%, respectively. Interexaminer agreement was 76.7% (p < 0.001) for all patients. CONCLUSIONS: FPT is widely used in children particularly when the visual acuity cannot be determined in an objective manner. The test may not be accurate and reliable in the detection of amblyopia and also in predicting the visual acuity difference between both eyes, even though it was found to show a high degree of agreement between examiners. In conclusion, it should be kept in mind that the reliability of FPT may be limited and the results should be interpreted with caution and be supported by other tests.

Why and when to prefer botulinum toxin injection in childhood strabismus?

Erkan-Turan K, Taylan-Sekeroglu H, Agin A, Sanaç AS. Why and when to prefer botulinum toxin injection in childhood strabismus? Turk J Pediatr 2017; 59: 684-687. The aim of this study was to investigate the indications and outcomes of botulinum toxin injection in children with strabismus. The medical records of children who underwent botulinum toxin injection were reviewed. Eighteen patients (13 boys, 5 girls) with a mean age of 9.08±5.93 (6 months to 17 years) years were enrolled in the study. The main indication and diagnosis, initial and final deviation at primary position and the presence of abnormal head position were all evaluated. The most common diagnosis was sixth nerve palsy (7 patients) followed by Duane`s syndrome (4 patients), acquired esotropia (2 patients), acquired exotropia (2 patients), consecutive exotropia (2 patients) and sensory strabismus (1 patient). The leading indications for botulinum toxin injections were the presence of abnormal head position, diplopia and ocular misalignment at primary position. All patients received monocular injection. Fourteen patients had one, 4 patients had more than one injection. The mean follow-up period was 2.78±0.94 months for the first post-injection visit and 21.64±15.23 months for the last visit. Five patients underwent strabismus surgery due to inadequate response to injection. No complication related to injection was observed. Botulinum toxin injection may be preferred in pediatric age group particularly in case of extraocular muscle palsy, diplopia and concomitant deviation either to provide ocular alignment prior to surgery or to prevent the detrimental effect of diplopia on binocularity. The intervention seems to be safe and repeatable in children even though surgery is still inevitable in particular cases.

Clinical risk factors for the development of consecutive exotropia: a comparative clinical study.

AIM: To compare a group of patients with consecutive exotropia with patients who had ≤10 prism diopters (PD) esotropia or no deviation postoperatively in terms of probable clinical risk factors for the development of consecutive exotropia. METHODS: The study recruited fourteen patients who developed consecutive exodeviation during follow-up period after the correction of esotropia who were categorized as group 1 and thirty-one patients who had still ≤10 PD esotropia or no deviation at the final visit that were considered as group 2. Clinical risk factors leading the development of consecutive deviation were analyzed as the main outcome measures. RESULTS: The mean age of patients was 4.57±3.11y in group 1 and 5.10±3.52y in group 2 (P=0.634). There was no significant difference of preoperative near and distant deviations among two groups (P=0.835, 0.928 respectively). The mean amount of medial rectus recession and lateral rectus resection was similar in both groups (P=0.412, 0.648 respectively). Convergence insufficiency and neurological diseases were more frequent in group 1 (P=0.007, 0.045). Accompanying neurological disease was found to be as a significant factor increasing the risk of the development of consecutive exotropia significantly [odds ratios (OR): 5.75 (1.04-31.93)]. CONCLUSION: Accompanying neurological disease appears to be a significant clinical risk factor for the development of consecutive exodeviation during postoperative follow-up after the correction of esotropia. However, larger studies are needed in order to interpret the results to the clinical practice and to ascertain other concurrent risk factors.