Continuous Wear of Hydrogel Contact Lenses for Therapeutic Use

Purpose: To investigate the efficacy and complications of continuous wear of etafilcon A for therapeutic use. Materials and Methods: The subjects were 228 eyes of 219 outpatients prescribed contact lens (CL) for one week of continuous therapeutic wear during 10 years. The reason for prescription of CLs, the primary disease, the duration of CL wear and the complications were assessed retrospectively. Results: The predominant reason for prescription of CLs was relief of pain or a foreign-body sensation (62.3%) and protection of the corneal epithelium (20.6%). The primary disease was post-penetrating keratoplasty (36.8%), followed by corneal epithelial erosion (14.5%), post-lamellar keratoplasty (14.0%) and bullous keratopathy (12.2%). The average duration of wearing single lens was 6.5 ± 3.2 days. The average duration of wearing CLs in total was 9.2 ± 10.7 months. The most frequent problem associated with continuous wear of CLs was their dropping out of CLs (12.3%). The complications associated with CLs included conjunctivitis with papillary hyperplasia, corneal erosion and superficial punctate keratitis, but corneal ulcer and corneal infiltrates were not found. Conclusion: Serious complications were not shown changing the lenses every week to keep to the prescribed time limit for continuous therapeutic wear, even if corneal epithelial barrier function is impaired.

A survey of corneal changes caused by daily wear silicone hydrogel contact lenses

The examination of the effects of second generation lotra filcon B silicone hydrogel(SiH)lenses on the cornea when worn for three years of daily wear.Material and Methods:55 healthy patients were divided into two groups:current hydrogel contact lens wearers refitted with lotrafilcon B lenses(Group 1;28 patients)and neophyte contact lens wearers(Group 2;27 patients).Each patient's subjective eye comfort was measured with a self-administered questionnaire.The corneas were analyzed using contact specular microscope to measure corneal thickness and the endothelium before the SiH lenses werefitted after four weeks,one month,six months,one year,two years,and three years of lens wear.Results:Subjective complaints of patients in Group 1 were reduced;however patients in Group 2 experienced discomfort during the first two to four weeks of use.In Group 1,objective examinations identified a decrease in endothelial cell density.In Group 2,the endothelial cell density increased slightly in the first two years but decreased after three years.The results indicate that lotra filcon B slows down the deleterious effects of contact lenses.The coe±cient of variation significantly decreased after six months in Group 1(0.47 vs 0.44;p?0:049),whereas,in Group 2,the hexagonal cells improved significantly after one month(27.78 vs 28.25;p=0.025).Conclusion:Based on the subjects involved and the period of time under examination,it can be concluded that high-Dk SiH lenses support the physiological metabolism and functions of the cornea by improving oxygen provision.

Cytotoxicity of Contact Lens Care Solution to Human Corneal Epithelium in Vitro

Purpose: To investigate the cytotoxicity of soft contact lens multi-purpose care solutions which are now in common use in China.Methods: The cell culture method was used. Cytotoxicity was indicated by significant increases in the number of dead cells relative to controls.Results: Cells were exposed to soft contact lens care solutions for 15 min. They were irregular in shape and variable in size. The intercellular space increased and variable in size.The in-tercelluar space increased and the cells became scrunken. With the time of exposure elongated , damage of cells became more severe.Conclusions: Four kinds of soft contact lens multi-purpose care solutions may have harmful effects on the culture of human corneal epithelial cells. Soaked lenses should be rinsed with saline before being placed in the eyes in order to reduce the potential toxicity of contact lens care solutions. Eye science 1998; 14 :45 - 47.

Clinic study on silicone hydrogel contact lenses used as bandage contact lenses after LASEK surgery

AIM: To compare the clinical performance of two types of silicon hydrogel contact lenses used as bandage lenses after LASEK surgery. METHODS: A prospective, double-masked study was conducted on 42 eyes of 21 patients who received binocular LASEK surgeries. The interocular difference in spherical equivalent power was less than -1.50D. Patients were randomly assigned to wear Galyfilcon A (Lens A) bandage contact lens in one eye and Balafilcon A (Lens B) in the fellow eye after the surgery. The responses to a subjective questionnaire on comfort of wearing, corneal epithelial status, conjunctival hyperemia, limbal neovascularization, lens fitting and contact lens debris were assessed 1 and 5 days postoperatively. Corneal endothelium was assessed before and 5 days after the surgery upon bandage lens removal. RESULTS: There was no difference between the two groups in terms of conjunctival hyperemia, limbal neovascularization, contact lens fitting, corneal epithelial status, corneal endothelium cell density (CD) and endothelium cell size (CS) at any postoperative visit. Complaints of discomfort, including foreign body sensation, pain and intolerance were statistically more among Lens B wearers at any postoperative visit (P < 0.05). Lens B appeared to attract much more debris than Lens A at the 5-day post-operative follow-up visit (P < 0.01). CONCLUSION: The two types of silicon hydrogel lenses investigated in this study demonstrated similar clinical performance in terms of corneal responses and lens fitting. However, Lens A showed a better performance in terms of comfort of wearing and deposit resistance.

Effects of rigid gas permeable contact lens on morphological parameters and vision-related quality of life in keratoconus patients

AIM: To evaluate the effect of rigid gas permeable contact lens(RGP-CL) on corneal morphological parameters and vision-related quality of life in keratoconus(KC) patients.METHODS: Totally 57 eyes of 30 KC patients who were followed-up for more than two years, including 17 RGP wearers(32 eyes) and 13 non-wearers(25 eyes) were retrospectively analyzed. Initial medical history and corneal topography were collected at baseline. Corneal topography, corneal aberration, optical coherence tomography, and vision-related quality of life questionnaires were performed at the last follow-up.RESULTS: According to corneal topography, increase of the flattest keratometric values was higher in RGP wearers than in non-wearers(P=0.038). The morphological parameters, including symmetry index of front corneal curvature(P=0.004) and Baiocchi-Calossi-Versaci index front(P=0.047), were lower in RGP wearers than in nonwearers. Vertical coma was smaller in RGP wearers than non-wearers in 3.0, 5.0, 6.0, and 7.0 mm pupil diameters, respectively(P<0.05). The environmental triggering domain of ocular surface disease index was worse in RGP wearers as compared to non-wearers(P=0.003). At the last followup, there were no significant differences in constituent ratios of KC progression, corneal thickness topography, epithelial thickness topography, morphological parameters of corneal topography, and other questionnaire scores between the two groups(all P>0.05).CONCLUSION: Long-term use of RGP does not worsen KC but may cause corneal epithelial remodeling to increase symmetry of corneal anterior surface, reduce corneal vertical coma and improve visual quality. However, RGP wearing causes a slight decrease in vision-related quality of life. The occurrence of ocular surface symptoms is mainly associated with environmental triggering factors.

EFFECT OF SHORT-TERM SOFT CONTACT LENS WEAR ON HUMAN OCULAR ABERRATIONS

Objective To evaluate the effect of short-term soft contact lens (SCLs) wearing on human ocular aberrations (HOA). Methods This prospective study included 50 eyes of 50 young volunteers wearing SCLs for 1 month. The ocular aberrations were measured by Allegretto Wavefront Analyzer. The root-mean-square (RMS) values of the general (RMSG), higher-order (RMSH), first to sixth order (RMS1 to RMS6) and aberration coefficients were analyzed. Results There were no significant differences in the mean values of RMSG, RMSH, RMS1 to RMS6 (P>0.05) and changes of absolute values of aberration coefficients between baseline and various visits after SCLs discontinuation. However, at d 1 after the discontinuation of SCLs, changes in coefficient values of the third-order aberrations (C6 to C9) were slightly higher than others, and C7 was the highest. The increase factors of RMS values were higher at 1 week and lower at the 2 week visit after SCLs discontinuation. The uniformity of dominating type in HOA and the corneal topography form was both about 60% after discontinuation of SCLs. The corneal thickness increased after SCLs wear and gradually decreased to baseline until 1 month discontinuation of SCLs. Conclusion The effect of short-term SCLs wear on human ocular aberrations is slight but profound. A month or more wait should be allowed before the short-term SCLs wearers are scheduled for wavefronted-guided LASIK.

Orthokeratology lens related infections

Orthokeratology is a reversible technique that temporarily changes the curvature of the cornea with the aim of addressing refractive errors. The United States Food and Drug Administration(FDA) granted approval for using reverse geometry contact lenses to correct myopia without any age restriction. Information from the pre-market applications to the FDA was rated as level Ⅱ evidence. Another unapproved use of overnight orthokeratology is for the prevention of myopic progression. Although orthokeratology is advocated to reduce myopic progression, there are limited long-term studies with substantial evidence of its benefits. Much of this evidence comes from non-robust experimental studies using historical or self-selected controls with relative high dropout rates. Although some positive results have been published in temporarily reducing the myopic refractive error and its progression, the use of these lenses can be associated with serious complications such as microbial keratitis. Microbial keratitis is a potentially vision-threatening adverse response associated with contact lens wear. In fact, contact lens wearhas been shown to be the predominant risk factor of microbial keratitis in some developed countries. Most of the published cases on overnight orthokeratology related microbial keratitis occurred in children or adolescents. Parents considering orthokeratology must make an informed decision about its temporary benefit and its potential for permanent loss of vision. The ophthalmic community should be reminded of the potential complications of orthokeratology.

接触镜在圆锥角膜中的临床应用及并发症研究进展

圆锥角膜是一种不断进展的致盲性眼病,其特征是角膜变薄和突起,伴有不规则散光和视力下降。早期圆锥角膜的不规则散光可通过框架眼镜矫正,对于中重度圆锥角膜的不规则散光,框架眼镜不再适用,接触镜成为患者矫正视力的最佳选择。接触镜种类繁多,在接触镜的选择上难以抉择,如长时间试戴镜片会增加患者的不适,影响整体感受,也大大增加了医生的工作量。因此,本文对接触镜的分类、接触镜在不同圆锥角膜类型中的应用、接触镜配戴中的并发症及其未来展望等方面予以汇总和讨论,以期了解接触镜在圆锥角膜中的临床应用与管理,有助于进一步发挥接触镜在圆锥角膜中的应用价值。

ICL植入术治疗高度近视术后早期眼前节形态的变化分析

目的探讨有晶体状眼后房型人工晶状体(ICL)植入术治疗高度近视术后早期眼前节形态的变化情况。方法选取60例(113眼)高度近视患者,均接受ICL植入术治疗。对比患者治疗前后裸眼视力、最佳矫正视力变化情况,眼前节形态变化情况[角膜厚度(CCT)、角膜曲率(K值)、中央前房深度(ACD)],角膜像差变化情况[角膜高阶像差(CHOA)、角膜低阶像差(CLOA)、角膜总像差(CTA)]。结果治疗后30 d、90 d、半年的裸眼视力、最佳矫正视力均优于治疗前(P<0.05)。治疗前及治疗后30 d、90 d、半年,角膜厚度分别为(532.50±25.40)、(532.54±23.17)、(534.64±22.55)、(532.97±24.10)μm,角膜曲率分别为(43.80±0.89)、(43.55±0.92)、(43.55±0.97)、(43.43±1.03)D,中央前房深度分别为(3.22±0.14)、(3.06±0.17)、(3.06±0.14)、(3.09±0.11)mm。与治疗前对比,治疗后30 d、90 d、半年的角膜曲率、中央前房深度均有所减小(P<0.05);治疗前后各个阶段,角膜厚度对比均无明显差异(P>0.05)。治疗后30 d、90 d、半年的CHOA均大于治疗前(P<0.05);治疗后30 d、90 d、半年的CLOA、CTA与治疗前对比均无明显差异(P>0.05)。结论高度近视患者应用ICL植入术治疗,患者的最佳矫正视力、裸眼视力均有所改善,角膜曲率变小、中央前房深度变浅、前房角变窄,患者术后早期眼前节形态良好,且较小影响角膜,安全性较高,可促进患者术后早日康复。

角巩膜镜对圆锥角膜患者视力和角膜参数的影响

目的:探讨配戴角巩膜接触镜对圆锥角膜患者视力和角膜参数的影响。方法:前瞻性研究。共纳入43例(83眼)圆锥角膜患者。配戴角巩膜接触镜,并分别在戴镜前、戴镜3、6 mo后行裂隙灯检查、客观验光和主观验光、裸眼视力(UCVA)和最佳矫正视力(BCVA)、角膜曲率(Kmax、K1和K2)、中央角膜厚度和内皮细胞计数检查。结果:配戴6 mo框架眼镜后平均BCVA(LogMAR)为0.34±0.23,角巩膜接触镜为0.03±0.05(P<0.001)。戴镜6 mo后,Kmax由52.80±5.93 D变为51.51±5.64 D(P<0.001),角膜中央厚度由483.84±34.69μm变为476.28±35.38μm(P<0.001),角膜中央细胞计数由2559.18±275.7 cells/mm^(2)变为2572.73±274.3 cells/mm^(2)(P<0.001)。结论:临床中角膜参数未发生明显变化,角巩膜镜可显著提高视力,且可安全用于圆锥角膜患者。

角膜接触镜在翼状胬肉切除手术后应用对视觉质量的影响

目的探讨与分析角膜接触镜在翼状胬肉切除手术后应用对视觉质量的影响。方法选择2019年9月—2022年12月在岐山县中医医院进行诊治的翼状胬肉患者88例作为研究对象,根据随机数表法将其分为角膜接触镜组与对照组,每组44例。两组都给予翼状胬肉切除手术治疗,对照组给予术后常规治疗,角膜接触镜组给予佩戴角膜接触镜治疗,观察与记录患者的视觉质量变化情况。结果两组患者术后4周的最佳裸眼视力明显高于术前1 d,且角膜接触镜组术后4周的最佳裸眼视力也明显高于对照组,差异有统计学意义(P<0.05)。角膜接触镜组术后4周的角膜水肿、结膜下出血、延迟性出血、高眼压等并发症发生率明显低于对照组,差异有统计学意义(P<0.05)。两组术后4周的角膜散光值均低于术前1 d,且角膜接触镜组术后4周的角膜散光值与对照组相比也显著降低,差异有统计学意义(P<0.05)。两组术后4周的眼部症状评分明显低于术前1 d,且角膜接触镜组术后4周的眼部症状评分也明显低于对照组,差异有统计学意义(P<0.05)。结论角膜接触镜在翼状胬肉切除手术后的应用能改善患者的最佳裸眼视力,降低患者的并发症发生率,降低患者的角膜散光值,改善患者的眼部症状。

Reversible grafting of antibiotics onto contact lens mediated by labile chemical bonds for smart prevention and treatment of corneal bacterial infections

Eye trauma, decreased immunity, and contact lens wear often cause serious bacterial infections and irreversible corneal damage. To realize the responsive release of antibiotics such as gentamicin sulfate(GS), a novel antibacterial contact lens was constructed through self-assembly of antibiotics loaded ADAGS/PEI(polyethyleneimine) multilayer films on the surface. Both in vitro and in vivo antibacterial tests demonstrated high efficient and fast antibacterial property based on the smart responsive to bacterial infections and reversible drug loading and release.

Management of corneal ulceration with a moisture chamber due to temporary lagophthalmos in a brain injury patient:A case report

BACKGROUND This study describes the use of a moisture chamber to treat corneal ulceration due to temporary lagophthalmos in a critically ill patient.CASE SUMMARY A 46-year-old woman was admitted to the intensive care unit after a car accident.She suffered multiple injuries that included brain injury and presented with moderately decreased consciousness and lagophthalmos in her right eye.Within 6 d,her consciousness improved considerably;at which time,exposure keratopathy occurred and worsened to corneal ulceration.Lubricating gel,antibiotic ointment,and bandage contact lens were all ineffective in preventing or treating the exposure keratopathy.Instead of tarsorrhaphy,a moisture chamber was applied which successfully controlled the corneal ulceration.The moisture chamber was discontinued when complete eyelid closure recovered a week later.CONCLUSION A moisture chamber may be an effective,noninvasive alternative to tarsorrhaphy for treating severe exposure keratopathy due to temporary lagophthalmos.

Effects of Contact Lens Wear on the Corneal Endotnelium and Sensitivity

The corneal endothelium of 38 contact lens wearers(74 eyes) and 74 normal eyes for control was photographed and analyzed with specular microscopy and the graphic processing system.The central corneal sensitivity and thickness were also measured.The results showed that the frequency

配戴离焦RGPCL对高度近视儿童角膜屈光力及散光量的影响

目的:对比观察高度近视儿童配戴离焦硬性透气性角膜接触镜(RGPCL)前后角膜屈光力改变,并分析配戴后镜片对角膜屈光力及散光量的影响。方法:自身前后对照研究。收集2019-06/2020-06在西安市第一医院眼视光中心就诊并验配离焦RGPCL的8~12岁高度近视儿童30例60眼。使用TMS-4N角膜地形图仪测量基线及戴镜0.5、1a时戴镜状态下角膜切向屈光力,分析角膜鼻侧(N)、颞侧(T)、上方(S)和下方(I)角膜最大屈光力值及中央顶点处角膜屈光力改变情况,同时以1mm为间隔采集前述4个方位角膜屈光力以及角膜顶点处屈光力,采集范围为1~4mm,分析戴镜前后各点位屈光力变化情况。戴镜0.5,1a时后要求停戴1wk后复测眼轴、屈光度和角膜地形图,分析戴镜后较基线时眼轴、等效球镜度、散光和角膜屈光力等改变情况。结果:配戴离焦RGPCL时鼻侧(N)、颞侧(T)、上方(S)和下方(I)的角膜最大屈光力在0.5、1a时较戴镜前均显著增加,与角膜顶点处屈光力相比均表现为正相对屈光力,与戴镜前的负相对屈光力相比具有显著差异。在戴镜0.5、1a时复诊时戴镜状态下角膜相对周边屈光力朝正屈光力方向改变,除T1点位周边负屈光力增加外,其余各轴向各点位周边屈光力均显著增加。配戴0.5a后角膜陡K值变平0.11±0.10D,simK值减少0.20±0.18D,1a后角膜陡K值变平0.10±0.12D,平均K值变平0.02±0.05D,simK值减少0.16±0.13D。戴镜0.5、1a时后角膜平K较基线变化无差异。结论:配戴离焦RGPCL状态下角膜最大屈光力较角膜顶点处均表现为正相对屈光力,且4条轴向上各点位角膜相对周边负屈光力均由负值转变为正值。戴镜1a内眼轴和等效球镜度均较基线时增加,而散光量减少,角膜屈光力呈陡K变平趋势。

β-环糊精-透明质酸改性pHEMA角膜接触镜水凝胶的制备与性能

利用β-环糊精-透明质酸(β-CD-crHA)对聚甲基丙烯酸羟乙酯(pHEMA)水凝胶进行改性研究。借助核磁共振波谱仪、红外光谱仪、原子力显微镜、接触角仪、紫外-可见分光光度计、电子万能试验机等对水凝胶的组成、表面形貌、水接触角、透光率、拉伸性能、泪液蛋白吸附、双氯芬酸负载与释放等性能进行表征。结果表明,β-CD-crHA含量的增加显著提高了pHEMA水凝胶的表面亲水性,有效抑制了溶菌酶和牛血清白蛋白的吸附,同时增加了pHEMA水凝胶对双氯芬酸的负载量并减缓其释放速率,但不降低其透光率、拉伸应变等基本性能,是一种有前景的角膜接触镜材料。

硬性高透气性角膜接触镜对圆锥角膜患者角膜光密度的影响

目的探讨硬性高透气性角膜接触镜(RGP)对圆锥角膜患者角膜光密度的影响。方法选取2020年1月至6月于甘肃省人民医院眼视光学中心就诊的圆锥角膜患者45例(45眼)作为研究对象。根据Amsler-Krumeich圆锥角膜分级方法对患者进行分级和分组。45例圆锥角膜患者中轻度(Ⅰ级)组15例(15眼)、中度(Ⅱ级)组15例(15眼)、重度(Ⅲ/Ⅳ级)组15例(15眼)。三组患者戴镜前及戴镜后3个月、6个月和12个月行常规视力、裂隙灯检查。采用Pentacam三维眼前节分析系统检测患者角膜最大曲率(K m)、最薄点角膜厚度(TCT)、角膜后表面高度(PCE)以及角膜光密度。角膜光密度主要分析角膜12 mm直径范围内的数值,以角膜顶点为中心,分别测量0~2 mm、>2~6 mm、>6~12 mm和整体0~12 mm范围内的角膜光密度。并根据角膜厚度将角膜分为3层,记录角膜前层(120μm)、后层(60μm)、中层(前后层之间厚度)和全层的角膜光密度。对比三组患者戴镜前后角膜光密度的差异,分析其变化与K m、TCT、PCE的相关性。结果戴镜前三组患者之间K m、TCT和PCE差异均有统计学意义(均为P<0.05),中度组和重度组患者K m和PCE大于轻度组,TCT小于轻度组(均为P<0.05)。轻度组和中度组圆锥角膜患者不同直径范围内前层、中层、后层和全层的角膜光密度在戴镜后与戴镜前相比差异均无统计学意义(均为P>0.05)。重度组圆锥角膜患者在戴镜后6个月0~2 mm、>2~6 mm直径范围内前层、中层和全层角膜光密度较戴镜前有升高的趋势,但差异均无统计学意义(均为P>0.05)。圆锥角膜患者0~2 mm前层角膜光密度变化(戴镜后12个月与戴镜前的差值)与戴镜前K m呈正相关(r=0.405,P=0.03)。0~2 mm、>2~6 mm前层角膜光密度变化与戴镜前PCE呈正相关(r=0.323,P=0.02;r=0.203,P=0.01)。0~2 mm、>2~6 mm前层角膜光密度变化与戴镜前TCT呈负相关(r=-0.168,P=0.03;r=-0.207,P=0.04)。其余不同深度直径范围内角膜光密度的变化与K m、PCE和TCT之间无显著相关性(均为P>0.05)。结论圆锥角膜患者长期配戴RGP后角膜光密度相对稳定,角膜透明度未有明显下降,RGP是矫治圆锥角膜患者安全且有效的手段。

软性接触镜和重组牛碱性成纤维生长因子滴眼液对自体角膜缘干细胞移植胬肉术后疗效对比

目的比较软性接触镜(SCL)和重组牛碱性成纤维生长因子(rb-bFGF)滴眼液对自体角膜缘干细胞移植(LSCT)胬肉术后疗效的影响。方法通过前瞻性对照研究,收集行手术治疗的翼状胬肉患者150例共150眼,按照随机数字表法分为3组,除每例术后予左氧氟沙星滴眼液、氟米龙滴眼液和典必殊眼膏(妥布霉素地塞米松眼膏)外,A组术后予佩戴SCL、B组术后予加滴rb-bFGF滴眼液、C组为对照组,比较3组患者术后疼痛、异物感、畏光症状的视觉模拟量表(VAS)评分、泪膜破裂时间(BUT)、泪液分泌试验(SIt)、最佳矫正视力(BCVA)、角膜上皮修复时间及复发率情况。结果观察3组患者术后1、7和30 d疼痛、异物感、畏光症状的VAS评分,术后不适症状明显好转,且A、B组患者的VAS评分低于C组,进一步比较A、B组,差别也有统计学意义(P<0.05)。3组患者术前的BUT和SIt比较,差别均无统计学意义(P>0.05);术后3个月,3组患者的BUT和SIt比较,差别有统计学意义(P<0.05),且A、B组患者的BUT和SIt值高于C组,但A、B组间差别无统计学意义(P>0.05)。术后3个月,3组患者的BCVA均较术前明显改善,差别有统计学意义(P<0.05),且A、B组患者的BCVA高于C组,但A、B组间差别无统计学意义(P>0.05)。3组患者角膜上皮修复时间比较,差别有统计学意义(F=55.115,P<0.05),且A、B组患者角膜上皮修复快于C组,但A、B组间差别无统计学意义(P>0.05)。术后6个月,3组患者的术后复发率比较,差别均无统计学意义(χ2=1.288,P>0.05)。结论SCL在早期可有效缓解LSCT胬肉术后的不适症状,rb-bFGF滴眼液和SCL治疗LSCT胬肉术后的疗效确切、安全可靠,均可以改善眼表的状态,维持泪膜的稳定性,促进术后角膜修复。

低中度近视患者睫状沟直径与角膜直径的相关性

目的:研究低中度近视患者在不同前房深度分组下水平睫状沟直径(HCS)、垂直睫状沟直径(VCS)与角膜直径的相关性。方法:回顾性研究。纳入2021-04/2022-04于上海普瑞眼科医院行有晶状体眼后房型人工晶状体(ICL)植入术前检查的低中度近视患者78例129眼,测量HCS、VCS、角膜水平直径(WTW)并进行比较。根据Pentacam测量所得中央前房深度(ACD)分为浅前房组(2.8mm≤ACD≤3.2mm)、中前房组(3.2mm<ACD≤3.4mm)、深前房组(ACD>3.4mm)3组,对各组组内及组间HCS、VCS、WTW进行比较,采用Pearson积矩直线相关分析及线性回归方程分析各组内WTW、HCS、VCS间的相关性。结果:总体及各前房深度组内,WTW与HCS间均无差异(P>0.05),而VCS与HCS、WTW均有差异(P<0.01)。各组内WTW与HCS、VCS均有相关性,但深前房组WTW与VCS间线性回归相关性较弱(r=0.470,R^(2)=0.221,P<0.01);浅前房WTW、HCS、VCS与中前房组、深前房比较均有差异(P<0.01)。结论:低中度近视患者行ICL手术,WTW不能完全替代HCS,但可使用WTW预测HCS;且因随前房深度增加WTW对VCS的预测性降低,而不能预测VCS。

Influence of overnight orthokeratology lens fitting decentration on corneal topography reshaping

Background:This retrospective study was designed to investigate the sole influence of orthokeratology(OK)lens fitting decentration on the Zernike coefficients of the reshaped anterior corneal surface.Methods:This study comprised a review of 106 right eyes and measurements of corneal topography both before OK and at 1-month follow-up visit.A routine was designed to calculate local corneal surface astigmatism and assist the determination of OK lens fitting decentration from pupil center.The pupil-centered corneal Zernike coefficients of baseline(PCCB)and post-treatment(PCCP)were calculated.Meanwhile,the OK-lens-centered corneal Zernike coefficients of post-treatment(OCCP)were also calculated and considered as the presumptive ideal fitting group without decentration.Relationships between lens fitting decentration and the change of Zernike coefficients including(PCCP−PCCB)and(PCCP−OCCP)were analyzed.Results:Patients with a mean age of 11±2.36 years old had an average spherical equivalent refractive error of−3.52±1.06 D before OK.One month after treatment,OK lens fitting decentration from pupil center was 0.68±0.35 mm.RMS of 3rd-order(P<0.05),RMS of 4th-order(P<0.001)and RMS of total high order(P<0.001)corneal Zernike coefficients were increased in PCCP by comparing with OCCP,which was solely caused by lens fitting decentration.Nevertheless,no significant difference was observed in C^(0)_(2)(P>0.05).For the high order corneal Zernike coefficients in(PCCP–OCCP),radial distance of decentration was correlated with C^(−1)_(3)(r=−0.296,P<0.05),C^(1)_(3)(r=−0.396,P<0.001),and C^(0)_(4)(r=0.449,P<0.001),horizontal decentration was significantly correlated with C^(1)_(3)(r=0.901,P<0.001)and C^(1)_(5)(r=0.340,P<0.001),and vertical decentration was significantly correlated with C^(−1)_(3)(r=0.904,P<0.001).Conclusions:OK lens fitting decentration within 1.5 mm hardly influenced the change of corneal spherical power for myopia correction,but significantly induced additional corneal high order Zernike coefficients including C^(−1)_(3),C^(1)_(3),C^(0)_(4),and C^(1)_(5).