Clinical features and treatment of near-work-related acquired esotropia

INTRODUCTION

大部分應用型本科院校已根據自身的專業特色，建立了相對成熟的校企合作機制。而電子商務實踐的教學改革，正好可以利用這一優勢，搭建適合電子商務課程的實踐平臺，以企業的實踐工作和社會發展趨勢為導向，為學生提供更接地氣的學習環境。應用型本科院校還可以聘請創新創業培訓團隊的企業講師做學生的“場外指導”，將工作實踐第一線的內容搬到教學實踐中，幫助學生制訂工作計劃，擬訂工作任務，以小組為單位展開競賽，能夠極大地提高教學效果。

With the development of society and the widespread popularity of portable electronic devices, the number of ACE patients has increased. Most of these patients suffer from distant diplopia, with mild or asymptomatic near symptoms that can be relieved after rest. They spend long periods using mobile devices, which eventually results in constant diplopia. This kind of ACE is temporarily being called near-work-related esotropia

. There have been few reported studies on esotropia,and its mechanism remains unknown, including its relation with the duration of near vision, dioptre, accommodation and convergence as well as the difference in binocular visual function, accommodation and convergence amplitude between patients and normal people. This study intends to explore the causes of the occurrence and development of this kind of esotropia and evaluate the therapeutic efficacy of botulinum toxin extraocular muscle injections by analysing the differences in accommodation and convergence, binocular vision and other functions between these patients and normal people.

SUBJECTS AND METHODS

To assess the effect of the treatment from the standpoint of the patients, each participant needed to subjectively assess the severity of their symptoms at each visit before and after treatment on a scale from zero to four. With higher scores,the patients experienced more diplopia: 0 meant no diplopia,neither distant nor near; 1 indicated occasional diplopia only at a distance; 2 meant occasional diplopia, both distant and near;3 suggested diplopia most of the time; and 4 indicated diplopia in the distance and near all the time (diplopia score 0:4).

In this study, from April 2015 to November 2018,107 patients with near-work-related esotropia who were treated in Beijing Tongren Hospital affiliated with Capital Medical University were recruited as participants in the experimental group. Another 30 peers without near-work-related esotropia were included in the control group

A total of 107 patients were included in the experimental group: 52 males (48.6%) and 55 females (51.4%). The average age was 31.06±10.64 (range 15-57)y. There were 30 participants in the control group:17 females (56.67%) and 13 males (43.33%). The average age was 32.1±7.97 (range 16-53)y. There was no significant difference in age (

=0.825) or sex (

=0.61) between the two groups (Table 1).

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The general ophthalmological testing included refraction, best-corrected visual acuity, slit-lamp and fundus exams. The patients’ primary characteristics were collected,such as their age, sex, time of onset, main symptoms and occupation. At the same time, the patients’ medical history,daily duration of close distance (≤30 cm) eye use and habit of taking off glasses to see near objects.

This study was conducted following the Declaration of Helsinki and was approved by the Ethics Committee of Beijing Tongren Hospital affiliated with Capital Medical University. All participants signed their informed consent.

For the patients and normal participants over 18 years of age, manifest refraction was performed; for those under 18,cycloplegic refraction with 1% tropicamide was performed first, followed by post-cycloplegic refraction the next day to get the final endpoint. The following data were measured after completing the refractive correction: adjustment amplitude(negative lens method), positive and negative relative accommodation (PRA and NRA, respectively), accommodative convergence to accommodation ratio (AC/A; gradient method),distant and near-horizontal squint angle (prism alternating cover test and Von Graefe method), distant and near-horizontal imaging function, binocular vision function and stereopsis(Worth four-point lamp, Synoptophore and Titmus near stereopsis).

Acute acquired comitant esotropia (ACE) has a large impact on binocular visual functions of patients. It is common among juveniles and adults

. Diplopia develops suddenly in most patients who also show esotropia without symptoms of ophthalmoplegia or organic lesions. This kind of esotropia usually has a certain binocular visual function

.Diplopia refers to the abnormal phenomenon of two images appearing when two eyes look at one object, which is caused by deviation of the visual axis and projection of the object image onto the macular fovea of one eye and the area outside the fovea of the other eye

.

Botulinum toxin type A (BTXA; Hengli, Lanzhou Institute of Biological Products) injection is a freeze-dried crystalline product; there are 100 units per bottle, where one unit is a 50% lethal dose in a mouse, which is equivalent to 0.04 ng

.All patients were injected with BTXA in the medial rectus of both eyes. Alcaine surface anaesthetic (0.5%) was used before injection. Under the guidance of an EMG magnifier, a monopole needle-like electrode was used for the medial rectus of both eye injections. The dose of each injection was recorded.All patients were reexamined ten months after treatment.

The software program SPSS 22.0(IBM, Chicago, USA) was used to conduct the statistical analysis. The continuous variables of normal distribution were expressed as the mean±standard deviation, the continuous variables of non-normal distribution were expressed as the median (interquartile range), and the categorical variables were expressed as the frequency (%). For two comparisons,each value was compared by a

-test when the data conformed to the normal distribution, while the non-normally distributed continuous data were compared using non-parametric tests.The counting data were tested by the Chi-square test. A value of

<0.05 was considered statistically significant.

Normally, accommodation of 1 D could cause a set of 3-5 prism dioptors of convergence (AC/A: 3-5)

. The data of the two groups were in the normal range. There was no significant difference between the two groups, but the AC/A of the experimental group was slightly higher than that of the control group. Although some studies have shown that the AC/A is constant over one’s lifetime

, it is still worthy of long-term observation.

RESULTS

Inclusion criteria: 1) bestcorrected visual acuity ≥1.0; 2) no history of prior esotropia or systemic disease; 3) seeing distant complexes was the first symptom, diplopia is horizontal ipsilateral, and the distance between objects in all directions is equal; and 4) near vision≥4h per day (distance between the eyes and the object ≤30 cm).Exclusion criteria: 1) patients with other systemic diseases; 2)patients with incomplete data.

According to the measurements, the recruited patients did not have presbyopia, and the influence of refractive error was excluded in the patients with glasses. So,both factors could be excluded. After the examination, only 2 of the 107 patients in the experimental group had remarkable overcorrection of myopia, while no remarkable overcorrection of myopia was observed in the control group.

The results of this study showed that the refraction of the two groups conformed to a normal distribution. In the experimental group, the refractive error was -3.63±2.56 D in the right eye and -3.61±2.39 D in the left eye. There was no significant difference in the refraction between the left and right eyes.In the control group, the refractive error was -2.80±2.56 D in the right eye and -2.61±2.39 D in the left eye. There was no significant difference between the two eyes. There was also no significant difference in the refraction between the two groups(Table 2).

In this study, 79.5% of the patients in the experimental group had a habit of taking off their glasses to see near objects, and 3.2% of the patients in the control group had the same habit. The rate of this habit in the experimental group was significantly higher than that in the control group (

=0.00; Table 3).

The results exhibited that the AC/A was (3.97±1.66)

/D in the experimental group and (3.20±1.15)

/D in the control group(

=0.089; Table 4). In the experimental group, the NRA was 2.18±0.61 D in the right eye and 2.25±0.64 D in the left eye;the NRA of both eyes was 2.37±0.73 D. In the control group,the NRA was 2.21±0.44 D in the right eye and 2.18±0.43 D in the left eye; the NRA of both eyes was 2.28±0.40 D (Table 5). It is worth noting that there was a significant difference in the PRA between the two groups (Table 6). In the experimental group,the PRA was -2.59±2.15 D in the right eye and -2.53±2.19 D in the left eye; the PRA of both eyes was -2.27±2.17 D. In the control group, the PRA was -4.21±1.93 D in the right eye and -4.37±1.87 D in the left eye; the PRA of binoculus was-3.73±1.45 D.

In the near-work-related esotropia group, 84.9% of the patients had far stereoscopic vision, 15.1% had no distant stereoscopic vision, 77.5% had near stereoscopic vision, and 22.5% had no near stereoscopic vision. In the control group, the number of people with far and near stereopsis was 100%, and there was a significant difference. Distant stereopsis was found in 84.9% of patients in the experimental group; 15.1% of the patients had no distant stereopsis. Additionally, 77.5% of patients had near stereopsis and 22.5% had no near stereopsis in the experimental group. In the control group, all patients had distant and near stereopsis. Based on the above data, the difference between the two groups was statistically significant.

The range of ex-fusion was (-6.49±4.22)° in the experimental group and (-6.77±1.81)° in the control group (

>0.05). The infusion range was (9.84±5.72)° in the experimental group and(22.04±8.71)° in the control group (

=0.000). The fusion range in the experimental group was smaller than that in the control group (Figure 1).

The follow-up results showed that in the near-work-related esotropia group, the duration of looking closely was (9.26±2.97)h, the onset time was (21.13±20.68)mo,the near esotropia angle was (17.08±11.98)

, and the distant esotropia angle was (19.07±11.68)

, demonstrating the significant difference between the distant and near squint angles (

<0.05).Twenty-seven patients received the BTXA injection treatment.The diplopia score was 3.57±0.39 before treatment and 0.47±0.64 after treatment, which evidenced that the diplopia symptoms of most patients improved. Ten months after treatment, the squint angles of distant and near vision were(4.07±3.86)

and (1.93±2.86)

, respectively. The difference between the pre-treatment and post-treatment values was statistically significant (

<0.05).

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After 10mo of treatment, the diplopia and esotropia of most patients had improved after treatment (

<0.05).

DISCUSSION

In the clinical trial, we noticed that the patients were able to describe their symptoms very clearly and precisely; some even listed the specific dates when they were or were not symptomatic. They were well educated and generally anxious.Additionally, convergence spasm, which is often provoked by fixation at near, is associated with certain psychiatric conditions

. This made us believe that there might be some predisposing psychological factors to near-work-related esotropia. We then attempted to qualify the personality trait of perfectionism in this group using a scale from 0 to 4, with higher scores tending toward perfectionism (self-serious level score 0:4).

The results of this study revealed that 84.9% of patients in the experimental group had distant stereopsis. Additionally,77.5% of patients had near stereopsis in the experimental group. In the control group, all patients had distant and near stereopsis. The results showed that there were significant differences. Of the patients with near-work-related esotropia,89.72% had ametropia of more than -1.0 D. These patients needed little or no accommodation when looking closely at something, but more convergence was still needed to achieve better proximal binocular vision that led to the occurrence of tonic convergence, visual proximity convergence and fusional convergence

. This made the patients unable to relax when adjusting their vision, resulting in distant-look diplopia. In this study, 79.5% of the patients with near-work-related esotropia had a habit of taking off their glasses to see nearby objects, as did 3.2% of the participants in the control group. There was a significant difference between the two groups. Therefore, it was speculated that taking off glasses to see nearby objects is one of the determinants inducing the onset of this kind of esotropia

. Most of the patients with ACE suffered acute onset, especially young people and adults

. Most patients had good binocular vision before the onset of esotropia and abnormal binocular retinas after the esotropia affected their stereoscopic vision

. Therefore, this examination demonstrated that the visual function of the patients was affected by esotropia. However, several studies have shown that there is no significant correlation between the time of onset and the prognosis of stereoscopic function.

近年來，在“健康中國”戰略下，受益技術驅動，響應分級診療政策，各大型公立醫院紛紛加大智慧醫療與全民健康事業的深度融合力度，旨在進一步改善患者就醫體驗，促進服務效率提升的智慧化項目相繼落地。

在教師對學生的評價方面，要采用平時性評價及終結性評價各占一定比例的方式。對于平時性評價，教師要根據學生的課堂表現、在線學習的登錄次數、在線學習時間及閱讀量、在線提交的作業完成情況、討論發言的總體表現、網絡無紙化測試成績等方面進行綜合評估。學