Corneal oedema during reverse piggyback scleral lens wear

Purpose

One clinical approach to address poor front surface wettability during scleral lens wear is the use of a “reverse piggyback” system (a soft contact lens applied to the anterior surface of a scleral lens). The aim of this study was to compare the magnitude of corneal oedema induced following short-term reverse piggyback scleral lens wear and standard scleral lens wear.

Methods

Ten young (mean age 22 ± 6 years) healthy participants with normal corneas were recruited. On separate days, central corneal thickness and fluid reservoir thickness were measured using optical coherence tomography before and after 90 min of standard scleral lens wear (Kerectasia Alignment Tangent Torus diagnostic lenses, hexafocon A, Dk 100 × 10⁻¹¹ (cm²/s)(ml O₂/ml × mmHg), Capricornia Contact Lenses, capcl.com.au ) and reverse piggyback scleral lens wear (the same scleral lens with a Dailies Total 1®, delefilcon A, Dk 140 × 10⁻¹¹ (cm²/s)(ml O₂/ml × mmHg), Alcon, alcon.com , applied to the anterior scleral lens surface).

Results

After correcting for small variations in the initial central fluid reservoir thickness, central corneal oedema was similar between the reverse piggyback (2.32 ± 1.15%) and standard scleral lens conditions (2.02 ± 0.76%; p = 0.45).

Conclusions

Following 90 min of lens wear, the highly oxygen-permeable reverse piggyback system did not induce a clinically or statistically greater magnitude of central corneal oedema compared with standard scleral lens wear in young adults with healthy corneas. This approach may be suitable to address poor front surface scleral lens wettability or to correct residual refractive error during diagnostic scleral lens fitting.     

长期戴用软性接触镜后角膜内皮细胞的改变

目的：观察软性接触镜长期戴用后对角膜内皮细胞的影响,探讨如何提高ＳＣＬ使用的安全度。方法;利用非接触式角膜内皮显微镜（ＳＰ－５００,ＳＥＥＤ Ｃｏ．Ｌｔｄ）,观察长期戴用ＳＣＬ的４８只眼角与角膜内皮细胞的改变。分为日间戴镜组和连续过夜戴镜组,并分别探讨戴镜期间的长短与角膜内皮变化的关系。同年龄组正常非戴镜眼的角膜内皮细胞参数作为对照观察。     

Relationship between corneal tissue and shape in short-term soft contact lens wear

Purpose

To investigate which morphometric and ocular surface tissue parameters are affected by short-term soft contact lens (CL) wear and to assess whether they carry related or independent information.

Methods

Twenty-two healthy participants wore silicone hydrogel (SiHy; MyDay, CooperVision) soft CLs for 8 h in their left eye. Corneal tomography and corneoscleral topography were captured before and immediately after CL wear. Central corneal thickness (CCT), corneoscleral parameters (limbus position and corneoscleral junction [CSJ] angle) and corneal tissue parameters (corneal transparency and homogeneity) were evaluated.

Results

Corneoscleral parameters (limbus position and CSJ angle) were independent of corneal tissue parameters (transparency and homogeneity) at baseline and after CL wear. CCT was independent of all the other parameters examined at baseline, but baseline values of corneal tissue parameters were moderately correlated with CCT change (transparency: r = −0.51; p = 0.007), homogeneity: r = −0.46; p = 0.02).

Conclusions

A complete characterisation of ocular surface changes following CL wear should consider corneoscleral topography and corneal densitometry simultaneously, since they carry complementary information.     

巩膜镜的临床研究进展

巩膜镜是一种拱形覆盖角膜及角巩膜缘的大直径硬性透气性接触镜,用于日间配戴。随着对巩膜镜相关的研究逐步加深,巩膜镜治疗眼科疾病被更多的应用到临床。与常规硬性透氧性角膜接触镜相比,巩膜镜着落在巩膜上,在镜片后表面与角膜前表面之间形成一个液态穹窿,能够创造理想的眼表环境,并且具有不接触角膜表面及角巩膜缘,保护角膜组织,矫正角膜不规则散光,减少高阶相差,延缓或避免相关眼部疾病采用手术治疗,应用范围广,稳定性好及配戴舒适等优点。镜片材料、设计工艺、专业人员配镜技术及眼科成像技术的提高等推动了巩膜镜的临床应用。目前巩膜镜主要用于解决不规则角膜、眼表疾病及屈光不正等眼科疾病。本文旨在对巩膜镜的发展历史、适应证、验配及相关并发症等方面进行简要的综述。     

儿童配戴角膜塑形镜后早期角膜生物力学变化特征

目的：探讨近视儿童配戴角膜塑形镜后早期角膜生物力学变化特征及相关因素。方法：前瞻性临床 研究。收集山东第一医科大学附属眼科医院2018年6月至2019年12月配戴角膜塑形镜的中低度近 视患者55例（109眼）,男28例,女27例,年龄（12.1±3.7）岁,等效球镜度（SE）为（-2.97±1.56）D。 在配戴前及戴镜后1 d、1周、1个月,采用可视化角膜生物力学分析仪（Corvis ST）检查患者角膜生 物力学相关参数,如变形幅度比（DAR）、综合半径（IR）、水平方向Ambrosio相关厚度（ARTh）、硬 度参数（SP-A1）以及Corvis生物力学指数（CBI）;Pentacam检查角膜曲率;角膜光学相干断层扫描 （OCT）检查中央角膜厚度（CCT）和中央角膜上皮厚度（CET）。采用单因素方差分析比较不同时间 点角膜生物力学指标、屈光度和角膜形态的变化;采用Pearson检验进行各生物力学指标间的相关分 析。结果：所有患者在配戴角膜塑形镜后裸眼视力（UCVA）明显提高,1个月时均达到0 LogMAR。 CBI在配戴后1个月内逐渐上升,1个月时最高,配戴后1 d、1周、1个月较配戴前差异有统计学意义 （F=11.52, P<0.001）。IR在配戴后上升,1周时处于最高值,配戴前后比较差异有统计学意义（F=3.11, P=0.027）。ARTh在配戴后下降,1周时最低,配戴前后差异有统计学意义（F=29.82, P<0.001）。CBI 与SE呈正相关（r=0.21, P=0.003）,与CET呈负相关（r=-0.16,P=0.041）;与CCT无明显相关性。结论： 儿童配戴角膜塑形镜后1个月内,角膜生物力学特性有下降趋势,主要的变化指标为CBI。SE越低, CET越厚;CBI改变越小,角膜的安全性越高。     

Corneal conjunctivalisation in long‐standing contact lens wearers

Background: There are many contact lens‐related ocular surface disorders. Some can damage the limbal region where stem cells are thought to be located in its basal cell layer. This damage can result in destruction and a deficiency of corneal stem cells. One important sign of this complication is corneal conjunctivalisation. The purpose of this study is to describe clinical characteristics of a series of long‐standing contact lens (CL) wearers with corneal conjunctivalisation (CC). Methods: In a one‐year (March 2004 to March 2005) retrospective unmasked study, 591 CL clinical histories (195 new patients and 396 review patients) were analysed. Results: There were 24 eyes of 14 myopic patients (93 per cent women) with CC without a specific disease entity known to cause limbal stem cell deficiency (LSCD). Conjunctivalisation occurred in the inferior limbus of three eyes (12 per cent). Only four patients (28.6 per cent) reported previous ocular symptoms. All were myopic with a mean spherical equivalent of ‐8.80 ± 5.00 (SD) dioptres (range from ‐1.75 to ‐21.50 D) and mean visual acuity 0.9 ± 0.2 (range from 0.4 to 1.2). The mean years of CL wear was 17.6 ± 8.5 (CI 95% 13.2 to 22; range six to 30). All were daily‐wear patients with a mean daily‐wear time of 12.5 ± 1.8 hours per day (CI 95% 11.6 to 13.4). Conclusion: Corneal conjunctivalisation is a contact lens‐related complication in asymptomatic patients. Optometrists can play an important role in early diagnosis, education and management of these patients.     

Pentacam Scheimpflug成像测量晶状体密度与torsional超声乳化参数间的关系

目的：评价运用Pentacam Scheimpflug成像测量晶状体核密度与torsinal超声乳化动力学参数(如：运用于老年核性白内障患者的超声能量水平、液体留存时间及液体量)间的关系。方法：此研究为前瞻性双盲研究。瞳孔扩大后运用Pentacam Scheimpflug 成像进行测量。白内障的等级由pentacam核密度测定法[ pentacam nucleus densitometry, PND;又名Pentacam核分段( Pentacam nucleus staging, PNS)软件]自主分为1到5个等级。超声乳化术后,自动在Infiniti Ozil IP超声乳化系统监视器上计算并显示总超声( U/S)时间、累计耗散能、Torsional U/S时间以及估算液体的使用情况。组间差异运用单因素方差分析( ANOVA )进行评定,多组分析运用Tamhane测试法,PND测量的晶状体密度与torsinal超声乳化动力学参数间的关系运用Spearman相关分析进行评定。界定P<0.05时具有统计学意义。
　　结果：此项研究包括125例患者(125眼),平均年龄为69.7±9.4岁(范围：48~88岁),其中61例男性、64例女性。 U/S总时间、torsional U/S时间、CDE及估算液体使用情况的范围分别为0.70~158.9s,0.70~158.5s,0.11~42.65和21~98mL. PND组间数据有统计学差异。评估超声乳化动力学参数与PND数据间关系后得出PND数据与总超声时间( r=0.767; P<0.01)、torsional超声时间(r=0.767;P<0.01)、CDE(r=0.758; P<0.01)及液体使用量(r=0.602;P<0.01)均有显著相关性。
　　结论：白内障手术前运用PND评分法获得核密度的客观程度可为超声乳化术中的参数提供可靠的预见性。因此,对每一位患者进行每一单项超声乳化参数的评估,有助于降低超声乳化能量的使用量,减少内皮细胞丢失和类固醇的使用,加速视力的恢复。     

短期配戴角膜接触镜对角膜形态和厚度的影响

目的探讨短期配戴软性角膜接触镜对角膜形态和厚度的影响。方法对25名青壮年近视志愿者(50眼)(等值球镜:-0.50~-7.25 D)统一配戴软性角膜接触镜1个月,测定摘镜后1个月内不同时间的角膜形态和厚度变化,并与戴镜前比较。结果戴镜前和摘镜后不同时间,角膜地形图形态构成、角膜地形图散光轴向的变化构成及一些角膜前表面形态相关指数无显著性差异(P>0.05)。戴镜前与摘镜后角膜地形图形态完全一致者占62.5%,且均以不对称领结形为著;在摘镜后1 d、1周、2周,角膜地形图散光轴向变化在16°以上及31°以上均超过30%和20%,直到1个月后仍有24%的眼角膜地形图散光轴向的变化在16°以上;角膜厚度在摘镜后1 d、2周均明显高于戴镜前(P<0.05),直到1个月后才与戴镜前接近,且受日均戴镜时间的影响。结论短期配戴软性角膜接触镜对角膜形态和厚度的影响虽轻微但复杂,摘镜后1 d变化最显著,随着时间的延长逐渐恢复,直到1个月后才与戴镜前基本一致。日均戴镜时间对摘镜后角膜厚度变化有影响。     

Corneal imaging with slit‐scanning and Scheimpflug imaging techniques

Modern anterior segment imaging techniques, such as slit‐scanning and Scheimpflug imaging, greatly improved the field of corneal imaging. Devices such as the Orbscan (Bausch & Lomb Surgical, Inc) and, more recently, the Pentacam (Oculus, Inc) and the Galilei (Ziemer Ophthalmic Systems AG) have brought a whole new range of clinical possibilities and sparked interest in the academic community. These new tomographers create three‐dimensional models of the cornea and enable the direct measurement of both the anterior and posterior surface elevations. In this paper, we present a review of some available literature on those systems, regarding their optical principles and their performance in current clinical applications.     

巩膜阶梯状切口人工晶状体植入术后角膜散光

目的：探讨巩膜阶梯状切口对人工晶体植入术后角膜散光的影响。方法：对43眼采用巩膜阶梯状切口白内障囊外摘出及人工晶状体植入术,术后早期以角膜曲率计测量及验光观察角膜散光的变化,并随机与常规的角膜缘切口对照。结果：巩膜阶梯状切口,对于减少术后角膜散光,提高视力优于常规的角膜缘切口。     

人工晶状体植入术后角膜散光

目的探讨人工晶状体植入术后角膜散光的规律与程度。方法随机对５１例５３眼人工晶状体植入术者进行了术前、术后０．５ｍｏ及术后６ｍｏ的角膜曲率计检查。结果术后均出现不同程度的逆规性角膜散光。结论多缝线的这种人工晶状体植入术后角膜散光在较低水平,且这种散光在６ｍｏ内趋向稳定。     

软性角膜接触镜相关性表层点状角膜上皮病变临床分析与防治探讨

目的：对于软性角膜接触镜相关性表层点卷入 角膜上皮病变（ＳＣＬＩ－Ｒ－ＳＰＫ）进行临床分析,探讨防治措施。方法：对于２０２８例ＳＣＬ配戴者的验配进行回顾性研究,对于１６８例ＳＣＬ－Ｒ－ＳＰＫ患者进行临床分析,探讨防治措施。结果：ＳＣＬ－Ｒ－ＳＰＫ发生率为８．２８％。位于睑裂部者占８０．９５％,发生率为６．７１％。弥漫型者占１５．４８％,发生率为１．２８％。４．１７％配适偏紧,但有５５．２０％未再复     

Comparison of corneal measurements in keratoconic eyes using rotating Scheimpflug camera and scanning-slit topography

AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera (Pentacam) and Scanning-slit topography (Orbscan IIz) in keratoconic eyes. METHODS: A total of 121 patients, 71 males (58.7%) and 50 females (41.3%) (214 eyes) with the diagnosis of keratoconus (KC) were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness (CCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), and pupil diameter (PD) were measured by a single examiner using successive instrumentation by Pentacam and Orbscan. RESULTS: There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD (3.46±0.40 mm vs. 3.38±0.33 mm, P=0.019) and PD (4.97±1.26 mm vs 4.08±1.19 mm, P<0.001) significantly larger than rotating Scheimpflug camera. The two devices made similar measurements for CCT (95% CI: -2.94 to 5.06, P=0.602). However, the mean difference for TCT was -6.28 (95% CI: -10.51 to -2.06, P=0.004) showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm (95% CI: 0.04 to 0.12, P<0.001) with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam (95% CI: 0.68 to 1.08, P<0.001). CONCLUSION: A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotating Scheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.     

Corneal biomechanics after rigid gas permeable contact lens wear in keratoconus eyes

Background:Evaluation of corneal biomechanical properties 3 months after using rigid gas permeable (RGP) contact lenses in keratoconus. Methods: In this prospective trial study, cases were 32 keratoconic eyes with no history of RGP lens wear. All eyes were examined with the Ocular Response Analyzer (ORA) and the Corneal Visualization Scheimpflug Technology (CORVIS-ST) to measure corneal hysteresis (CH), corneal resistance factor (CRF), deformation amplitude (DA), applanation velocity (AV) 1 and 2, applanation length (AL) 1 and 2, and peak distance before and 3 months after iftting aspheric RGP lenses. The effect of the correlation between contralateral eyes and maximum keratometry were controlled for in the analysis. Results were compared using repeated measures analysis of covariance. Results:At 3 months, neither the increases in mean CH (0.14±2.77 mmHg, P=0.789), CRF (0.41±4.35 mmHg, P=0.612), AV1 (0.03±0.17 m/s, P=0.301), AV2 (0.11±0.59 m/s, P=0.299), AL1 (0.44±1.56 m/s, P=0.118), AL2 (1.16±5.06 m/s, P=0.211), and peak distance (0.19±1.29 m/s, P=0.409), nor the decrease in mean DA (0.03±0.17 mm, P=0.402) was statistically signiifcant. Conclusions: Results in our series of patients indicated that 3 months of RGP lens wear had no signiifcant impact on corneal biomechanics, and perhaps non progression of keratoconus. Therefore, RGP lenses can be regarded safe and appropriate in keratoconic patients.     

The effect of different thickness scleral lens on corneal parameters in eyes with keratoconus

Purpose:To investigate the impact of different-thickness scleral lenses (SLs) on corneal thickness, curvature, and fluid reservoir thickness in keratoconic eyes.Methods:Schiempflug imaging and AS-OCT was captured before and immediately following 6 h of SL wear. Different-thickness lenses were used while keeping the other parameters the same. The timing of the measurement for day 1 and day 2 was matched to allow for the control of the confounding influence of diurnal variation.Results:Immediately after 6 h of lens wear, no statistically significant difference (P > 0.05) was noted in corneal edema in any region and quadrants between thin- and thick-lens wearers. The calculated percentage of corneal edema was also within the range of overnight closed eye physiological swelling. Pentacam measured higher central corneal thickness compared to AS-OCT in both baselines and after 6 h of lens wear. The current investigation reported minimal but not statistically significant (P > 0.05) flattening in anterior and steepening in posterior curvature parameters in both thin and thick SLs. The mean reduction in the fluid reservoir thickness was 80.00 ± 3.99 and 79.36 ± 3.84 microns after 6 h of thin- and thick-lens wear, respectively, which was not statistically significant (P > 0.05). A statistically significant positive correlation (r = 0.67, P = 0.02) was found between lens thickness and change in anterior steep k with thick-lens wear.Conclusion:Central lens thickness of 200–400 mm did not cause any significant change in corneal curvature and fluid reservoir thickness and did not induce clinically significant corneal edema after short-term SL wear.