Clinical Characteristics of Intermittent Esotropia

Purpose: To evaluate clinical findings and surgical outcomes of intermittent esotropia.Methods: We retrospectively reviewed the medical records of 23 patients (aged 9-42 years) who presented with intermittent esotropia between January 2007 and December 2020. We analyzed the age at onset, angle of deviation, presence of symptomatic diplopia, fusional state, near stereoacuity, and surgical results.Results: The mean age at onset was 19.9 ± 8.0 years and mean duration of esodeviation was 23.4 ± 27.1 months. Mean follow-up time was 13.0 ± 15.6 months. All patients except three had symptomatic diplopia, and 78.3% showed intermittent diplopia. Mean angles of deviation were 21.6 ± 10.3 prism diopters (PD) at distance and 20.2 ± 10.4 PD at near. Twenty-one patients (91.3%) were myopia. No patients had amblyopia and one had dissociated vertical deviation. On Worth’s four-dot test, five patients (21.7%) showed diplopia and four showed suppression at both distance and near. The other patients showed fusion at near or distance. Eleven patients underwent surgical correction. At the final examination, all patients achieved successful motor alignment and fusion with resolution of diplopia. Only two patients (18.2%) achieved normal 60 arcsec stereopsis, and six attained subnormal stereopsis.Conclusions: The main symptom of intermittent esotropia was diplopia. Surgical treatment was effective in achieving good postoperative motor alignment and fusion. However, successful motor alignment did not guarantee recovery of fine stereopsis.

Investigation of complex surfaces of propellers of vehicles by a mechatronic profilograph

Introduction. The technology of investigation of screw propellers complex surfaces, which include the marine and aircraft propellers of vehicles, mechatronic profilers for the implementation of reverse engineering, is considered. A review of the scientific literature shows that at present the problem of monitoring complex surfaces of products at various stages of its life cycle requires further research, since the use of available devices and methods does not always provide the necessary accuracy, technological effectiveness and sufficient information on measurements. The purpose of the work is to develop a new technology for studying complex surfaces of propellers, which include marine and aircraft propellers of vehicles by means of a mechatronic profilograph to implement reverse engineering. Methods. The paper considers the implementation of the innovative technology for studying complex surfaces of propellers using the developed mechatronic profilograph. This ingenious mechatronic profilograph is designed to measure the profile and study the shape of complex surfaces of various products, as well as to determine the geometric and morphological parameters of these surfaces. On the basis of theoretical studies the main design and technological parameters are found and the hyperbolic dependence of the angular rate of the laser sensor movement on the scanning radius is determined for the developed mechatronic profilograph. For example, if a constant pitch of the trajectory along the Archimedes spiral is 2 mm, the value of the sensor angular rate should gradually decrease from the maximum value of 2 rad/s to the minimum value of 0.574 rad/s, i.e. by 3.484 times. Results and discussion. It is revealed that the use of cylindrical coordinates for processing the obtained data by a profilograph is logical and has a number of advantages. An express analysis of the propeller surfaces with rotary symmetry is carried out and differences in the shapes of the surfaces of the propeller blades by deviation values in the longitudinal and transverse directions for different radii are established. On the basis of the experimental data, a two-factor power model describing deviations with a determination coefficient of 0.967 is obtained, according to its analysis, it is clear that on average the angle of deviation in the perpendicular direction to the radius  - increases from 0 to 0.3, and the angle of deviation along the radius  increases from 0 to 5.4.

The reliability of the angle of deviation measurement from the Photo-Hirschberg tests and Krimsky tests

Objective To compare the angle of deviation measured from Photo-Hirschberg testing and Krimsky testing, with that from an alternate prism cover test (APCT) in strabismus patients. Methods A cross-sectional study was conducted in Songklanagarind Hospital, Thailand. Thirty-three strabismus patients were photographed for analysis by Photo-Hirschberg testing using computer software. The corneal light reflex displacement, converted into prism diopter (PD), was compared to the angle of deviation measured with APCT. Twenty-eight strabismus patients were tested with the Krimsky test. Data were analyzed using Pearson correlation and paired t-tests. The study excluded 4 intermittent exotropia cases, 1 intermittent esotropia case and 2 which cases missing data for krimsky test. Results The mean±SD of the deviation angle, measured by APCT with a fixation target at 30 cm and 6 m; were 48.09±16.34PD and 47.82±15.73 PD, respectively. At 1 m, the difference in the angle of deviation measured from APCT and the Photo-Hirschberg test within 10 PD were 58.8% and 63.6%, for ET and XT, respectively. The difference in the angle of deviation measured from APCT and Krimsky tests within 10 PD in ET and XT were 86.7% and 80.0%, respectively. At 4 m, the difference in angle of deviation measured from APCT and Photo-Hirschberg tests within 10 PD in ET and XT were 58.8% and 54.5%, respectively; whereas, the difference in the angle of deviation measured from APCT and Krimsky tests within 10 PD in ET and XT were 80.0% and 70.0%, respectively. Conclusion The reliability of Krimsky test was better than Photo-Hirschberg test for measuring an angle of deviation.

Improving the safety of train lighting devices in curves

The article presents a system for correcting the direction of the light beam of a rolling stock searchlight in curved sections of the track. The dependence of the angle of deviation of the axis of the light beam of the searchlight on the angle of inclination of the trolley is determined. The principle of correction of the light beam of a rolling stock searchlight using a matrix LED searchlight is described.

Infranuclear Eye Movement Disorders

Infranuclear motility disorders are such of the cranial nerves, the extraocular muscles or changes in the orbit but definitely peripheral to the nuclei of the cranial nerves. Characteristic are movement deficits, a compensatory head posture and the pattern of incomitancy. The secondary angle of deviation is usually larger than the primary. Combined pareses suggest a lesion in the cavernous sinus, orbital apex or a multilocular event. It is essential to rule out supranuclear disorders, especially if the motility deficit is atypical. For clarification, an individual risk assessment is recommended, paying particular attention to risk factors.

Initial overcorrection after surgery for intermittent exotropia in children less than 4 years old: Comparison with older children

Purpose While initial overcorrection after exotropia-correcting surgery is widely accepted for a favorable long-term outcome, some have not advocated such overcorrection in younger children owing to concerns regarding rapid deterioration of bifixation ability. This study aimed to evaluate the relationship between initial overcorrection after intermittent exotropia surgery and the surgical outcome in patients aged <4 years. Methods In this retrospective study, 391 patients who had undergone surgery for intermittent exotropia were classified into two groups according to the age at surgery: <4 years old (group Y [young], 130 patients) and 4–16 years old (group O [old], 261). The patients were subdivided into three groups according to the angle of deviation at postoperative 1 week: esophoria-tropia (ET) ≥10 prism diopters (PD) (subgroup I), ET 1–9 PD (II), and orthotropia or exophoria-tropia (XT) (III). We compared the surgical outcomes between the two groups and among subgroups; then, we analyzed consecutive esotropia patients. Results The mean exodeviation was smaller in the order of subgroup I, II, and III at every postoperative visit (p<0.05) in group Y but showed no difference among subgroups after 2 years in group O. Consecutive esotropia occurred at 1 month, postoperatively, in 6.9% and 2.6% of the patients in groups Y and O (p = 0.133), respectively. However, it persisted in two and one patient in groups Y and O, respectively, until the last visit. Conclusion Early overcorrection after intermittent exotropia surgery was a safe and desirable result in terms of motor outcome in children aged under 4 years, as well as for children aged between 4–16 years.

The Results of Modified Hang Back Recession Surgery in Infantile Esotropia

PURPOSE:Bimedial rectus recession is one of the surgical treatment options for infantile esotropia. It is mainly performed with the Hang-Back technique, which has undesirable side effects. In this study, this technique has been modified, and its results are discussed.METHODS:The files of 120 patients followed with the diagnosis of infantile esotropia and treated bimedial rectus muscle recession using the modified Hang-Back technique were reviewed retrospectively. Cases were evaluated by the time of surgery, coexistence with inferior oblique muscle weakening surgery, and presence of refractive error. The factors investigated on the results of surgical treatment were determined as age, gender, amount of hyperopic refractive error, application age, amount of horizontal deviation, amount of recession, stereopsis, fusion, age of surgery.RESULTS:When the cases were divided into subgroups which were the time of surgery, the operation performed with inferior oblique weakening surgery and presence of refractive error; the difference between preoperative and postoperative 1st month, 6th month, and 1st-year angle of deviation was statistically significant in all three groups (p < 0.001).CONCLUSION:This novel technique aims to prevent unwanted movement of the muscle in the horizontal and vertical axis and a gap in the middle of the recessed muscle, seen in the classical Hang-Back technique. The difference between the preoperative and postoperative angle of deviation was statistically significant. Also, over and under-correction and the development of alphabetic pattern deviation were less common in our modified technique.

Combined Recession–Resection of The Superior Rectus Muscle in the Treatment of Dissociated Vertical Deviation.

Purpose This is retrospective study that evaluates the use of combined recession-resection of the superior rectus muscle in the treatment of dissociated vertical deviation (DVD) Methods The medical records of 21 patients with bilateral DVD were retrospectively reviewed. Preoperative data were extracted for age, gender, BCVA (logMAR), amblyopia, angle of stereopsis, previous strabismus surgeries and angle of deviation. All included patients received resection of 2.5 mm of the superior rectus muscle prior to its recession in an amount determined by the maximum DVD angle. The main outcome measure was postoperative angle of DVD at the end of six postoperative months and success was identified as absence of manifest DVD . Results The mean angle of preoperative DVD was 18.09 PD in the right eye and 16.76 PD in the left ‎eye‎. The mean amount of SR recession was 8.9 ‎±1.4 ‎mm in the right e‎‎ye and 8.7 ‎±1.5 in the left ‎eye with symmetrical surgery performed in only 7 patients. Mean postoperative angle of DVD was ‎5.96‎ in the right eye and ‎5.86 ‎in the left eye. Surgical success was achieved in 15 patients (71%). Conclusions Combined recession-resection of the superior rectus muscle seems to be an effective technique in the management of DVD and could represent a good alternative to other surgical procedures.

Acute Diplopia of Non-neurological/restrictive Etiology: a Retrospective Comparative Study.

PurposeTo describe and compare the clinical features and management of different types of acute diplopia of non-neurological/restrictive etiology.MethodsRetrospective comparative study carried out reviewing medical records of forty-eight patients referred to one tertiary referral center between January 2016 and June 2020.Thirty-two were classified as Acute Acquired Comitant Esotropia (AACE), 3 cases as type I (group A), 12 cases as type II (group B) and 17 cases as type III (group C). Four cases were classified as Decompensated MonoFixation Syndrome (DMFS) (group D), 6 cases as High Myopia-Comitant Esotropia (HMCE) (group E) and 6 cases as Sagging Eye Syndrome (SES) (group F). Patients with diplopia of neurological or restrictive etiology were excluded.All patients underwent a complete orthoptic and ophthalmologic assessment with a postoperative follow-up of 11.4 ± 4.1 months (ranging from 5 to 20 months).ResultsType 3 AACE (Group C) was the most frequent cause of diplopia among the groups (35.4%). High Myopia-Comitant Esotropia (Group E) and Sagging Eye Syndrome (Group F) were significantly older at onset and baseline examination (both P= .001). Constant acute onset was significantly more represented in Group C (P= .026) while all patients in Group F showed an intermittent onset. Near angle of deviation was significantly lower in Group E and Group F compared to Group C (P= .030). A significantly higher near divergence fusion amplitude was detected in Group C (P= .017). Compensation (angle of deviation increasing) at Prism Adaptation Test (PAT) was observed in 75% of total study population, without significant differences among group. Fifty-four % of the total sample underwent surgery as first or secondary treatment choice with good functional results regardless of pathogenesis.ConclusionDemographic characteristics and clinical features (refraction, type of diplopia at onset, angle deviation, fusion amplitudes, response to prismatic correction) can differentiate different types of acute or subacute onset diplopia of not neurological/restrictive etiology.

Efficacies of preoperative prism adaptation test and monocular occlusion for detecting the maximum angle of deviation in intermittent exotropia

Background The efficacies of prism adaptation test (PAT) and monocular occlusion (MO) and their optimal test durations to detect the maximum angles of deviation at near and distance in eyes with intermittent exotropia (IXT) were assessed and compared. Methods We retrospectively reviewed the medical records of 72 patients with IXT. All the patients had undergone the initial strabismus surgery between April 2015 and October 2018 and had been preoperatively tested by both PAT and MO performed on different days for 30 and 60 min. Near and distance deviations after 30 and 60 min of PAT and MO were compared to their baseline measurements obtained immediately after prism wear and before occlusion by alternate prism cover test. The near/distance measurements and required test duration to reveal the maximum deviation angle were also compared between PAT and MO. Results Compared with the baseline, the near deviation by PAT significantly increased after 30 (P < 0.05) and 60 (P < 0.01) minutes but not the distance deviation. However, the increase after 30 min was not significant. By MO, neither near nor distance deviation showed a significant difference from the baseline after 30 and 60 min. PAT showed a significantly larger near deviation than MO at 30 and 60 min, but a larger distance deviation by PAT was only observed at 30 min. Conclusions In patients with basic and convergence insufficiency types of IXT, a 30-minute PAT appears to be more effective than MO in revealing the maximum angle of deviation before strabismus surgery.