Evaluation of the safety of anterior capsule staining with trypan blue under air: a retrospective analysis

INTRODUCTION

Trypan blue group After performing the limbal stab incisions, an air bubble was injected into the anterior chamber using a 27-gauge cannula, followed by the application of 0.03% trypan blue on the anterior lens capsule. Ⅰmmediately afterwards, the anterior chamber was irrigated with balanced salt solution, in order to wash out the trypan blue. After irrigation, the fluid in the anterior chamber was exchanged with DisCoVisc (hyaluronic acid 1.6%, chondroitin sulfate 4.0%,Alcon laboratories, Fort Worth, TX, USA). A 2.8-mm superior clear corneal incision was made, and CCC was performed without assisted illumination (Figure 1A).

Trypan blue has been used by many surgeons over the years and no toxic effects have been reported in literature

.Recently, prospective studies performed by van Dooren

and Nagashima

demonstrated the safety of trypan blue in staining in cataract surgery. However, the two studies differed in the staining methods employed and the rate of endothelial cell density (ECD) loss. The elucidation of these disparities requires further research.

There were postoperative changes in the mean percentage of HC in the trypan blue group (5.62% loss,

=0.100 at one month; 6.55% loss,

=0.304 at three months), but the differences were not statistically significant. Ⅰn the illuminator group, the mean percentage of HC was observed to decrease significantly, one month after the surgery (

=0.028) and subsequently, continued to improve and increased to the preoperative levels by the third postoperative month (Table 2).There was no significant change in the mean CV in either group at three months postoperatively (Table 2).

SUBJECTS AND METHODS

Ethical Approval The current study was approved by theⅠnstitutional Review Βoard of the Pusan National University Hospital (2004-004-089) and was performed in accordance with the principles of the Declaration of Helsinki.

IPF是一種下呼吸道慢性炎癥類疾病，以侵犯肺間質及肺泡壁為主要特征，而中性粒細胞與吞噬細胞則參與機體炎癥反應，并破壞病患肺泡結構，使其胸膜纖維及小葉間隔明顯增厚，肺泡間隔的纖維化成分明顯增多，繼而融合、擴張為囊狀陰影[1]。為此我院將近段時間確診的98例IPF病患作為研究對象，旨在觀察HRCT運用于IPF中的診斷價值，作報道如下。

渦輪流量計安裝時應確保流量計的上游前、下游后具有一定長度的直管段，一般要求上游直管段長度不低于20D，D為管道公稱直徑，下游直管段不低于5D，以消除旋渦流等流體流速分布不均產生的測量誤差。流量計應工作在儀表系數曲線線性區域內，瞬時流量應在分界流量以上，以保證其測量的準確性。要特別注意脈沖放大器的選型和配置，其選用和正常運行直接關系著工況流量數據傳輸的準確性。

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The present study included 86 patients, who were categorized into two groups: the trypan blue group and the control group.Patients who underwent anterior capsule staining with 0.03% trypan blue under an air bubble were assigned to the trypan blue group (

=45), and those who underwent surgical procedures, which were performed using an intracameral illuminator were assigned to the control group (illuminator group;

=41).

Patients aged<40y, those with advanced nuclear cataract of grades >ⅠⅠⅠ, a history of ocular trauma or surgery,corneal disease with a preoperative ECD <2000 cells/mm

,pseudoexfoliation syndrome, ocular inflammatory diseases,and glaucoma; those who presented with intraoperative or postoperative complications that required additional surgery within three months after the primary procedure, and those whose vascular arcades were observed during the preoperative examinations despite the vitreous hemorrhage were excluded from the study.

Surgical Procedures All surgical procedures were performed by a single surgeon (Park SW). Considering the fact that vitrectomy induces nuclear sclerotic cataracts

,simultaneous cataract surgery was performed with vitrectomy in all the patients aged >50y after obtaining informed consent.Ⅰn the patients aged <50y, cataract surgery was performed selectively on the basis of individual counseling.

Οne hour before surgery, the pupils were dilated using tropicamide 0.5%, phenylephrine 0.5% (Tropherine; Hanmi,Seoul, Republic of Korea), and cyclopentolate HCl 1%(Οcucyclo; Samil, Seoul, Republic of Korea), applied five times at 10-minute intervals. Retrobulbar anesthesia was performed in all the patients.

Continuous curvilinear capsulorhexis (CCC) is considered as a critical step in the procedure of phacoemulsification:an incorrect CCC increases the risk of intraoperative complications

. Adequate red reflex is essential for performing CCC; hence, inadequate red reflex can impede the successful completion of the procedure. Consequently, several methods have been proposed to facilitate the visualization of the anterior capsule during the procedure of CCC in such cases

. Among the aforementioned methods, the only method approved by the US Food and Drug Administration (FDA) is the use of trypan blue; this technique has been extensively used as an adjunct staining agent in cataract surgery. Furthermore, a few authors have recommended the use of trypan blue in cataract surgeries performed by inexperienced surgeons, even in the patients with good red reflex

.

Patient Selection The present study involved a retrospective analysis of the medical records of patients presented with vitreous hemorrhage who underwent the procedures of pars plana vitrectomy, phacoemulsification and intraocular lens(ⅠΟL) implantation, during the time period from January 2014 to July 2017 at Pusan National University Hospital.Patients with poor or inadequate red reflex caused by vitreous hemorrhage, which impeded the clear identification of the anterior capsule, were included in the study. Prior to December 2015, owing to the limited domestic supply of trypan blue,an intracameral illuminator was used as an ancillary method to visualize the anterior capsule during CCC. The use of 0.03% trypan blue commenced in January 2016 after the reestablishment of the domestic supply.

Control group (Illuminator group) After performing the limbal stab incisions, the anterior chamber was directly filled with DisCoVisc (Alcon laboratories). Subsequently, a 2.8-mm superior clear corneal incision was made, and an intracameral endoilluminator was used to perform CCC, as described by a previous study (Figure 1Β)

.

Cataract surgery was performed using a Constellation machine(Alcon Laboratories, Ⅰnc., Fort Worth, TX, USA). Standard phacoemulsification, including nuclear fracturing (divide and conquer), cortical clean-up, and the implantation of a foldable three-piece acrylic ⅠΟL (Hoya PC60AD, Hoya, Tokyo, Japan),was performed in all the patients in both the groups. Sutureless pars plana vitrectomy was performed using 25-gauge instrumentation using the Constellation machine and a noncontact viewing system (Resight 700, Carl Zeiss Meditec AG,Jena, Germany). Postoperatively, all the patients received 0.5%moxifloxacin (Vigamox; Alcon, Fort Worth, TX, USA) and 1% dexamethasone (Maxidex; Alcon, Fort Worth, TX, USA),instilled as eye drops, four times daily for a maximum time duration of one week.

Clinical Data Collection and Corneal Endothelial Status Assessment Preoperative and postoperative assessments included the following investigations: best corrected visual acuity (ΒCVA), slit-lamp examination, and intraocular pressure(ⅠΟP) assessment. The investigations were performed at the baseline and one month and three months after the surgery.The etiologic factors related to vitreous hemorrhage were compared in both the groups. Ⅰn addition, systemic diseases such as diabetes, hypertension and chronic renal insufficiency were also reviewed.

奇巧生來到河邊，伸長機械臂，打算撈起那些黑色的木頭。誰知木頭竟然活了，主動躲開了機械手，這讓奇巧生十分詫異。正在此時，黑火兒朝黑木頭吐出一道火焰，大喊：“危險！”

Ⅰnitially, trypan blue at high concentration of 0.3% was used as an exclusion dye to determine the viability of the endothelial cell layer in donor corneas

. Trypan blue 0.06% was first used for anterior capsule staining in cataract surgery by Melles

. Yetik

reported that trypan blue can effectively stain the anterior capsule at concentrations as low as 0.0125%.The authors considered that 0.0125% trypan blue was too weak to stain the anterior capsule and hence, 0.03% trypan blue was used in cataract surgery.

應用所提出的ACMLGD結合文本挖掘和情感分析技術，提取在線評論中正面評價、反面評價及綜合評分等信息開發了自動一致性系統，該一致性系統可集成到現有的ERP系統中，用于支持企業的大型群決策活動，也可用于集結互聯網產品用戶偏好、挖掘發現客戶總的一致性意見。現……