Congenital ocular counter-roll:a review of cases treated exclusively by ophthalmologists

AIM:To review the demographics,clinical manifestations,and surgical experiences of patients with congenital ocular counter-roll,whose treatments were performed exclusively by ophthalmologists.METHODS:A retrospective review was conducted consisting of patients who received strabismus surgery between 2017 to 2019.Patients with obvious ocular counter-roll were included.RESULTS:A total of 7008 patients who received strabismus surgery,28(12 males,16 females)were diagnosed as congenital ocular counter-roll,accounting for 0.40%.All patients were initially misdiagnosed:21 patients were misdiagnosed as superior oblique palsy(SOP),3 as inferior oblique overaction,2 as dissociated vertical deviation(DVD),1 as superior oblique overaction with A-pattern exotropia,and 1 as medial rectus palsy.The mean±SD age was 12.4±9.4 y(range 2.5-36 y).The most common clinical findings included ocular counter-roll,vertical deviation or vertical deviation combined with outward deviation and head tilt.At follow-up,an excellent surgical result was achieved in 20 patients.Preoperative horizontal deviation of 26±24 prism diopter(PD)and vertical deviation of 18±12 PD were reduced to 0±12 PD(P=0.0001)and 3±4 PD(P=0.001),respectively.CONCLUSION:Congenital ocular counter-roll is a rare supranuclear vertical strabismus caused by congenital abnormalities involving vestibule-ocular reflex pathways.In addition to ocular counter-roll,the most salient clinical features included,but are not limited to,hyperdeviation,outward deviation,overelevation in adduction and head tilt.

New extrusion process of Mg alloy automobile wheels

The recent research and development of forged magnesium road wheel were reviewed.Methods of flow-forming,spin forging of manufacturing a forged magnesium alloy wheel were introduced.A new extrusion method was investigated especially. Extrusion from hollow billet was proposed in order to enhance the strength of spoke portion and reduce the maximum forming load. By means of the developed technique,the one-piece Mg wheels were produced successfully by extrusion from AZ80+alloy.At the same time,the existing problems on the research and development of forged magnesium road wheel were analyzed.The impact testing,radial fatigue testing and bending fatigue testing results show that AZ80+wheel can meet application requirement in automobile industry.

Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts

Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because of multi-axis rotation, multi-local loading along the circumference, and radial-axial compound deformation. Analytical or experimental methods cannot fully understand CRS. Meanwhile, numerical simulation is an adequate approach to investigate CRS with comprehensive understanding and a low cost. Thus, a finite element (FE) model of CRS was developed with the FORGE code via meshing technology, material modeling, determining the friction condition, and so on. The local fine mesh moving with the roller is one of highlights of the model. The developed 3D-FE model was validated through a CRS experiment by using a tubular blank with a 720 mm outer diameter. The developed 3D-FE model of CRS can provide a basis for parameter optimization, process control, die design, and so on. The data on force and energy predicted by the 3D-FE model can offer reasonable suggestions for determining the main mechanical parameters of CRS machines and selecting the motors. With the predicted data, an all-electric servo-drive system/machine with distributed power was designed in this work for CRS with four pairs of rollers to manufacture a large-sized, thinwalled, cylindrical part with 6000 mm diameter.

Affected-Ear-Up 90°Maneuver Proves That Nystagmus Does Not Occur by the Stimulation to the Macula of the Utricle

Background: The utricular macula is located on the floor of the utricle, approximately in the plane of the lateral semicircular canal, and is oriented to respond best to lateral tilts and side-to-side or fore-and-aft translations of the head. However, the details of the otolith ocular reflex are unknown. Pathophysiology of transient direction-changing geotropic positional nystagmus is a canalolithiasis in the lateral semicircular canal. The principle of affected-ear-up 90° maneuver is moving debris from a long arm to the utricle, therefore debris stimulates the utricular macula in the sitting position after the treatment. Objective: To clarify whether nystagmus occurs by the stimulation to the macula of the utricle. Methods: The subjects were 10 patients with lateral semicircular canal canalolithiasis. After the diagnosis, we performed affected-ear-up 90° maneuver immediately. We observed eye movements in the sitting position (chin-down 30°) just after the treatment. Results: No one showed nystagmus in the sitting position after the treatment. In all patients, positional nystagmus disappeared within 7 days after the treatment. Conclusion: Nystagmus does not occur by the stimulation to the macula of the utricle. Hence, we cannot assess the function of the utricle by the analysis of eye movements, and ocular counter-rolling is considered to be a semicircular canal ocular reflex.

Eye Movements Induced by Stimulation to the Otolith Organs

Background: We have been performing a canalith repositioning procedure for benign paroxysmal positional vertigo. When we adopted the Epley maneuver for posterior semicircular canal type, and affected-ear-up 90° maneuver for lateral semicircular canal type, we noticed that no nystagmus occurred in the sitting position just after treatment. Despite direct excitation to the utricle by the pathological debris, none of the subjects complained of dizziness. Thus, we hypothesized that nystagmus and dizziness do not occur by stimulation of the otolith organs. Objective: The aim of the study was to observe and record the eye movements induced by the otolith organs to confirm our hypothesis. Materials and Methods: Twelve healthy humans were tested. In the sitting position, the head was tilted to the right ear by 45° and vice versa. Afterward, the head was bent forward by 90° (nose-down), and the subject’s seat was reclined to the head-hanging position. Each position was kept for five seconds. We interviewed the subjects to assess their dizziness. Results: None of the subjects showed nystagmus and complained of dizziness in every position. Conclusions: Nystagmus does not occur by the stimulation to the otolith organs;therefore, ocular counter-rolling is a semicircular canal ocular reflex.