Factors associated with corneal astigmatism change after ptosis surgery

INTRODUCTION

Blepharoptosis, an eyelid disorder, can cause visual disturbance at any age ranging from infants as congenital ptosis to aponeurotic ptosis in the elderly. Other types included mechanical, myogenic, and neurogenic ptosis

. Patients may experience a decreased vision as the covering lid constricts the superior visual field and/or causes refractive errors, mainly corneal astigmatism.

敦礼挣扎着坐起来，一阵眩晕差点把他击倒。他赶紧闭着眼向后靠在卧床的靠背上，一动不动，像睡着了一样。靠背上紫红色的金丝绒衬得他的脸卡白卡白的，胡茬子也更加分明，使得下巴看起来不是平常那种青灰色，而是深得近乎黑色了。他的上半身穿了一件浅灰色的棉质睡衣，腰部以下搭着被子，被子的一角翻转过来，露出比背面颜色略深的里子。被子不是很厚，比靠背略浅一些的紫色，上面点缀着几团花纹，花纹以浅绿色为主，夹杂着少许黄色，刺绣精美得让人止不住地浮想联翩。

Explanation have been proposed indicating the causation of corneal astigmatism in ptosis patients to be a result of eyelid pressure against the cornea, which alter the corneal shape toward with-the-rule (WTR) astigmatism

. The corneal astigmatism degree is changeable postoperatively based on several reports, some showed significant results

.Postoperative axis shift has also been reported. Wilson

demonstrated a trend of a decreased degree of WTR astigmatism in patients who underwent ptosis surgery. A similar result was reported in Savino

's study

. However,Merriam

found the opposite trend of an increased WTR astigmatism to also be possible.

“艺术人”身份是艺术家最本质的、区别于他人的基本特征。大众普遍意识中的艺术家通常意味着具有较高的审美能力和娴熟的创作技巧，从事艺术创作并取得了一定成就的人。其最基本的特征首先是具有艺术天赋的，这种天赋可能体现在笔触运用上、色彩调和上，也可能体现在音符流动中，诗词歌赋、琴棋书画，不一而足；其二是富有艺术感性，极强的移情通感能力，即对于美的事物的丰富的感受力和想象力，又因这种极度的感性而充满激情，将自我感受通过艺术手段表现在笔触、音符和语言等形态之中。正像黑格尔描述的，真正的艺术家都有一种天生自然的推动力即将自己的情感思想即刻表现为艺术形象的直接的需要。

Few studies have been conducted to identify factors associated with the degree of astigmatism change after ptosis surgery

. In this study, we evaluated corneal astigmatism value of patients who underwent ptosis surgical repair to find the association between patient factors and postoperative corneal astigmatism change. The changing pattern of corneal astigmatism axis after surgery was also identified.

SUBJECTS AND METHODS

All patients underwent levator resection procedure by the same experienced surgeon, with informed consent obtained preoperatively. This study was approved by the Human Research Ethics Committee of the Faculty of Medicine Naresuan University in accordance with the Declaration of Helsinki.

This is a retrospective study evaluated patients diagnosed with congenital or acquired ptosis who underwent ptosis surgical repair at Oculoplastic Service of the Department of Ophthalmology, Naresuan University Hospital,Phitsanulok, Thailand between September 2017 and August 2019.

A comprehensive ophthalmological examination was performed. Data recorded included visual acuity, refraction,anterior segment exam, fundus exam, eye motility, and levator function.

Patient factors were identified and recorded.The data included age at operation, sex, preoperative marginreflex distance (MRD) 1, and preoperative degree and axis of corneal astigmatism. Subgroups of each factor were classified to evaluate the associations with the degree of astigmatism change at 6-week postoperatively.

Several studies attempted to compare the degree of corneal astigmatism change among various eyelid surgery procedures.A retrospective study by Zinkernagel

found a significant change of postoperative corneal astigmatism in patients who underwent ptosis surgery and blepharoplasty with reduction of the entire fat pad, in contrast to insignificant value in the groups with skin-only blepharoplasty and blepharoplastywith reduction of the medial fat pad. This study reflects the correlation between the severity of eyelid abnormality and the significant astigmatism value change postoperatively. A similar result was reported by Kim

; patients underwent levator resection exhibited more corneal curvature change compared with those who underwent blepharoplasty.

从图2可以看出，施钾明显促进了钾素积累量的增加，与NP处理相比，施钾处理的钾积累量增加了35.87%～68.97%， 等施钾量条件下，100%OF 处理的钾积累量最小，为 156.71 kg／hm2，30%OF＋70%CF 处理的干物质积累量最大，达到 194.89 kg／hm2，其他处理的钾积累量处于两者之间，且无明显差异。

Astigmatism value was obtained from an average of 3 consecutive values measured using Nidek Tonoref II Autorefractor Keratometer. Exclusion criteria were previous corneal surgery, presence of pterygium, keratoconus, severe ocular surface disease, neurological/mechanical/traumatic ptosis, or preoperative MRD1 of ＞3.

A range of means astigmatism change in our study was 0.25 to 0.65 D, corresponding to a previous finding by Brown

which reported an average of 0.6 D in corneal astigmatism change in patient underwent reposition lid ptosis.

All congenital ptosis patients underwent supramaximal levator resection and all acquired cases underwent a levator resection procedure. Skin crease was marked at the desired height. The 2% lidocaine with 1:100 000 adrenaline was injected subcutaneously along the eyelid crease. Skin incision was done with a scalpel blade no.15.Dissection was made deeper through orbicularis muscle, orbital septum and preaponeurotic fat with Westcott scissors and electrocautery to identify the underlying levator aponeurosis.The levator aponeurosis was then dissected off the tarsal plate and extend superiorly off the müller's muscle to the desired level. In case of supramaximal levator resection, the dissection was continued superiorly to a level above Whitnall's ligament.Partial-thickness 6-0 silk sutured was placed from upper one third of tarsal plate in horizontal mattress fashion to the levator muscle at a desired level and tied with a temporary bowtie for intraoperative level adjustment. Additional suture was placed nasally and temporally. Eyelid crease was made with prolene 7-0 suture between inferior cut edge of pretarsal aponeurosis and levator aponeurosis. Skin was closed with interrupted sutures nylon 6/0.

A Shapiro-Wilk test was used to evaluate the normality of the data. Variables were reported in mean value±SD. The analysis comparing preoperative and postoperative astigmatism values was done using Wilcoxon signed ranks test. A

-value of ＜0.05 was considered statistically significant. The prevalence of axis pattern was reported in percentage. The analysis was performed with SPSS version 17.0.

专栏小编：接下来我们谈谈经济方面的内容。2018年11月中国制造业P MI为50.0，环比小幅回落0.2个百分点，处于临界点；欧元区11月制造业P MI终值51.8，创2016年8月以来低点；美国11月I S M制造业指数59.3，好于预期的57.5。对此，三位专家怎样看这些数据？

RESULTS

Forty-two eyes of 28 patients were included in the study. Of the 42 eyes, 8 eyes of 7 patients were congenital ptosis with mean age of 16.75y (range, 4-53y) and 34 eyes of 21 patients were acquired ptosis with mean age of 63.71y (range, 38-76y).Data representing the means of pre- and post-operative corneal astigmatism were summarized in Table 1. Overall, the means of postoperative astigmatism showed a reduction value compared to means of preoperative astigmatism in all subgroups, except for the subgroups of eyes with astigmatism of ＜1.5 D and eyes with oblique astigmatism. The means of astigmatism change at 6-week postoperatively of each subgroup ranged from 0.25 to 0.65 D.

The analysis of different astigmatism values between preand postoperative by the Wilcoxon signed ranks test showed a significant value in only one subgroup which is eyes with preoperative astigmatism of ≥1.5 D (

=0.006; Figure 1).Thirteen of 18 eyes (72.2%) with preoperative astigmatism of ≥1.5 D showed a reduction degree of astigmatism after eyelid surgery, with the mean astigmatic change of 0.65±0.52(0-1.75) D.

Refractive surgery is one of the most popular elective ophthalmic procedures performed in the world. Denisova and Barmettler

suggested that patients electing to have ptosis repair, should be fully healed prior to any refractive surgery to allow both refractive changes and eyelid positions to stabilize prior to the refractive surgery. We agree with this suggestion, especially in patients with either high preoperative astigmatism or dry eye syndrome.

After a surgical repair, the WTR group showed a predominant reduction of WTR astigmatism in 57.9% (11/19). Other patterns of changes were also observed, including an increased degree of WTR astigmatism in 26.3% (5/19), a change to oblique axis in 10.5% (2/19) and one eye with no astigmatism change (5.3%). Meanwhile, the eyes with preoperative ATR astigmatism exhibited a rising degree of ATR in 37.5% (6/16),a reduction in 50% (8/16), no change in one eye, and one eye with a change to oblique axis. Also, most of the eyes with preoperative oblique astigmatism experienced a shift of the axis towards ATR astigmatism (5/7; 71.4%).

DISCUSSION

Previous studies reported that ptosis lid can generate pressure onto superior cornea which leads to the change of cornealcurvature, resulting in corneal astigmatism, particularly a WTR astigmatism

. Several reports established the modifiability of this condition as observed in the change of corneal astigmatism,either in the degree or axis, after surgical correction

.Wilson

evaluated the effect of eyelid lifting, using eyelid speculum, and found a reduction of WTR astigmatism in cornea with more than 1.00 D of WTR astigmatism. Savino

also found a significant reduction of WTR astigmatism in patients who underwent ptosis surgical repair.

Cataract and ptosis may co-exist in the same patient. The change of corneal astigmatism of at least 0.5 D might cause a visual problem in patients with high demand visual function

.Also, in our study, significant postoperative astigmatism change was found in a subgroup of eyes with astigmatism of≥1.5 D with a mean change of 0.65±0.52 (0.00-1.75) D. Regarding findings above, this might put patients who underwent cataract surgery prior to lid correction, at risk of unsatisfied visual outcome from a refractive change after ptosis surgery, despite a precise initial intraocular lens (IOL) calculation. Although the majority of patients in a subgroup of preoperative corneal astigmatism of ≥1.5 D showed a decreased degree of astigmatism postoperatively (72.2%), the direction was unpredictable and other patterns were observed, including the increase in the degree of astigmatism value and axis change.The latter might substantially affect patients requesting for toric-IOL implantation.

Age was categorized into ≥50y and ＜50y; MRD1 values was divided into -2 to 0 and 1 to 3. The degree of preoperative corneal astigmatism was divided into ＜1.5 diopters (D) and≥1.5 D, and axis of corneal astigmatism was classified as WTR(steep axis within 90°±30°), against-the-rule (ATR; steep axis within 0° to 30° or 150° to 180°), and the axis which falls beyond these ranges is classified as oblique astigmatism.

To our knowledge, there are limited studies attempting to identify predictive factors for a corneal astigmatism change in patient who underwent ptosis repair surgery

. Our study,therefore, analyzed postoperative corneal astigmatism change based on patient factors. The results showed a significant postoperative astigmatism change in a subgroup of eyes with more severe baseline preoperative astigmatism value, in other words, eyes with preoperative astigmatism of ≥1.5 D (

=0.006).

Unlike two previous mentioned studies which exhibited the correlation between high severity of lid pathology and high value change of astigmatism postoperatively

, our study showed no significant result in group with severe ptosis as indicated by MRD1. Further investigation should be done to assess the association between severity of ptosis and amount of preoperative astigmatism.

The primary outcome was the degree of corneal astigmatism change at 6-week postoperatively. The secondary outcome was the corneal astigmatic axis pattern, pre- and post-operative.

一杭暗自笑了一下，继续往前走。雪萤磨磨蹭蹭地跟在后面，不时停下来要求休息一下。一杭说：“是不是累了？来，把包给我，我帮你拿。”说着伸过手来，雪萤一把将提包藏到身后，慌忙说：“不用！我自己能拿。”

The majority of preoperative eyes demonstrated WTR astigmatism pattern (45.2%), compared with 38.1% of ATR and 16.7% of oblique pattern (Table 2) with a mean age of 42.15±24.14, 67.25±7.20, and 60.42±10.72y respectively.

WTR astigmatic pattern is found predominantly in children and will gradually transform to ATR astigmatism with increasing age

. We also know that the ptosis lid can have a pressure effect on peripheral cornea which leads to a WTR astigmatism

. Our patients revealed a similar trend as the majority of ptosis patients showed a WTR astigmatism (45.2%)preoperatively. For patients with ATR astigmatism (38.1%),an older mean age (67.25±7.20y) was found, compared with 42.15±24.14y in WTR group. This might reflect the substantial effect of ATR patterns found in aging cornea overcoming the effect of lid pressure. Another confounding effect, such as the duration from onset of ptosis to date of surgery, which may or may not influence the reversibility of the cornea astigmatism value, has not been included in this study.

According to axis patterns, most of the previous studies reported that corneal astigmatism tend to decrease the degree of WTR (or increase the degree of ATR) astigmatism after eyelid surgery

. In our study, the changing of axis after ptosis correction was non-uniform. Although many cases with preoperative WTR and oblique astigmatism showed a decreased degree of WTR astigmatism after surgery, this was not revealed in the preoperative ATR group. Moreover, the preoperative axis was a statistically insignificant factor in our study. Therefore, it cannot be used as the predictive factor for postoperative corneal change.

综上所述，螺内酯对神经母细胞瘤细胞具有诱导凋亡的作用，其机制可能与调节Bcl-2和Bax表达平衡有关。由于螺内酯体外诱导SK-N-SH细胞凋亡的剂量比较低，提示该药有一定的抑瘤作用，对于寻求神经母细胞瘤更好的生物和化学疗法具有潜在的价值。

Although numbers of reports have revealed a similar trend of significant corneal astigmatism change after ptosis surgery,follow-up periods were varied, ranging between 6wk and 4mo

. Long term change was evaluated in a recent study from Yamamoto

which showed a significant astigmatism change at 6mo postoperatively. While all of the suggested durations to perform cataract surgery after ptosis repair were proposed according to the results of follow-up periods being reported, there was an uncertainty on stability of astigmatism value postoperative and a longitudinal study should be done to assess a definite timing at which steady astigmatism value was achieved

.

全新林肯飞行家Aviator量产车型于2018洛杉矶车展正式全球上首发。作为首款充分诠释“静谧之旅”品牌理念的车型，全新飞行家Aviator定位大型豪华SUV，代表着林肯最新家族设计思路。新车的一些外形创意灵感源自飞行器，林肯星辉式前格栅造型勇毅，三排座椅布局的第二排支持独立座椅。全新林肯飞行家Aviator拥有两种动力系统，并提供四驱系统和自适应悬架系统。其中，汽油动力车型的排量适合中国市场，搭载3.0升V6双涡轮增压发动机和10速自动变速箱；插电混合动力车型同样搭载双涡轮增压发动机，新增纯电和储能两种驾驶模式。

纵观资本发展的历史，总是伴随着野蛮，总是会表现出其最丑陋的一面，往往是货币成了人们追求的唯一目标。同时，货币把所有东西都降低为某种抽象的观念，在自己的运动中把自己降低为某种量化的存在。马克思在分析了资本主义异化劳动的历史暂时性之后指出，只有这样的条件，才能为每个人的自由全面发展建立现实基础，而这又是社会长期发展的自然产物。

Some studies found an astigmatism pattern correlated with corneal ectasia in ptosis patient. However, ptosis alone was insufficient to cause corneal ectatic disease which was known to be a multifactorial condition

. A prospective study found tomographic value of subclinical keratoconus in severe congenital blepharoptosis

. Another study from Kim

also reported ptosis inducing superior keratoconus. In our study, we excluded overt keratoconus cases as its natural history may confound with the effect of lid pressure to normal cornea. However, as we do not perform tomography in routine practice, it might be possible to falsely recruit subclinical keratoconus case into the study. Limitations were expected,given that this study was a single-center retrospective study.Also, the astigmatism values obtained from autokeratometer,may result in less comprehensive data in comparison to corneal topography values in which data was not available in this study since the method was not performed routinely in our center.The attempt at a long-term data analysis was incapable due to the relatively high rate of loss follow up.

Nevertheless, in patients undergoing ptosis surgery, the data demonstrated for first time the association between postoperative corneal astigmatism change and a preoperative corneal astigmatism of ≥1.5 D. Thus, in patients with such predictive factor, surgery sequence should be considered, as conducting ptosis surgery prior to cataract or refractive surgery might provide a better refractive outcome, especially with toric-IOL implantation.

采用如图所示的传统模型标定模板时，由于椭圆柱体与圆柱体的投影相互重叠，对其进行投影数据的分离困难。另一方面，若原模板的旋转中心与椭圆和圆的中心共线，特别是如果旋转中心靠近椭圆或圆的中心时，相当于在所有投影角度或部分投影角度产生了模板旋转角度信息的缺失，形成了确定投影角度的盲区。在这种情况下，为求解所有的投影角度序列，需要对模板进行建模，采用解析方法或者数值方法求得。但无论采用哪一种方法，都比较复杂，而且无法体现这种模板的优势。

Mongkolareepong N initiated the project, designed the data collection tools, monitored the data collection for the whole trial, wrote the statistical analysis plan, cleaned and analyzed the data, as well as drafted and revised the manuscript. Mekhasingharak N initiated the project, designed the data collection tools, monitored the data collection for the whole trial, revised the manuscript,approved the final manuscript prior to journal submission, and supervised the study. Pimpha O designed the data collection tools, and revised the manuscript.

None;

None;

None.

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