Comparison of silicone and non-silicone hydrogel soft contact lenses used as a bandage after LASEK

PURPOSE: To evaluate two different soft contact lens materials for continuous-wear bandage contact lenses after laser epithelial keratomileusis (LASEK). METHODS: A prospective, observer-masked study was conducted of 32 eyes of 16 consecutive patients. Inclusion criteria were candidates for bilateral LASEK, myopia of < or = -6.00 diopters (D), astigmatism < -1.50 D, and bilateral best spectacle-corrected visual acuity of 20/20 or better. Patients were randomly selected for a balafilcon A (PureVision; Bausch & Lomb) bandage contact lens in one eye and a poly-2-hydroxyethylmethacrylate-co-methacrylate glycerol (EquiS 60; mark'ennovy) in the fellow eye. Corneal epithelial status, conjunctival and limbal hyperemia, lens movement, contact lens debris, and the responses to a subjective comfort questionnaire were assessed postoperatively. The parameters were evaluated preoperatively and 1 and 5 days postoperatively. Paired Student t test and chi-square tests were used when appropriate. RESULTS: Thirty-two eyes of 16 consecutive patients who underwent LASEK to correct low to moderate myopia were analyzed. The mean spherical equivalent refraction was -3.25 D. There was no difference in conjunctival or limbal hyperemia, contact lens debris, or subjective comfort between lenses at any postoperative visit. In contrast, the corneal epithelial status was statistically better in the eyes with a silicone bandage contact lens 5 days after LASEK (P = .01). CONCLUSIONS: The results suggest that the bandage contact lens material used after LASEK affects the corneal epithelial healing process.     

Clinical performance of microchannel contact lenses.

PURPOSE: It has been suggested that microchannels placed on the posterior surface of hydrogel contact lenses increase transverse lens movement and therefore increase tear mixing. Lens designs, which can improve tear exchange without adversely affecting lens performance, may play a significant role in improving the safety of contact lens wear. Our aim was to investigate the effect of posterior lens surface microchannels on contact lens performance. METHODS: A randomized, single masked pilot study was conducted. Fifteen experienced hydrogel lens wearers were randomly assigned to wear a microchannel lens (MC) in one eye and a standard hydrogel lens design (STD) in the fellow eye over a period of 6 hours. A range of objective and subjective clinical performance measures were assessed, including visual acuity, lens movement, comfort and patient preference. RESULTS: There were no significant differences between the MC and STD lenses with respect to vision measures, corneal staining, and bulbar and limbal redness (p > 0.05). The MC lenses produced significantly less conjunctival staining than the STD lenses and showed greater lens movement in primary gaze (p < 0.05). Lens distortion with blinking was evaluated through topographic assessment of the contact lenses on eye, and no significant differences were observed in central distortion levels between the two lens designs (p > 0.05). Subjective evaluation of the lenses with respect to comfort, vision, and overall satisfaction did not vary significantly between the two lens types (p > 0.05). CONCLUSIONS: The results of this study suggest that posterior lens surface microchannels do not adversely affect contact lens performance or subjective lens preference over a short-term wearing period. The MC lenses appear to produce less physiological impact on the conjunctival surface than STD lenses with less conjunctival staining observed with the MC lenses. Clinical investigation of the performance of this type of lens design in a larger group of subjects, over longer wearing periods, is warranted.     

硅水凝胶角膜接触镜senofilcon A和comfilcon A在LASEK术后应用的对比研究

目的 对比硅水凝胶角膜接触镜senofilcon A和comfilcon A在准分子激光上皮下角膜磨镶术(LASEK)术后应用的临床效果.方法 采用前瞻性随机双盲自身对照试验的方法,纳入行LASEK患者39例(78眼),术后同一患者一眼配戴senofilcon A角膜接触镜(A组),另一眼配戴comfilcon A角膜...     

全角膜羊膜覆盖和绷带型角膜接触镜用于较大翼状胬肉切除术的疗效比较

目的：针对较大翼状胬肉,采用胬肉切除、角膜缘干细胞移植联合全角膜羊膜覆盖术,或胬肉切除和角膜缘干细胞移植术后配戴绷带型角膜接触镜进行治疗,观察两种方法的临床效果。

方法：将侵及瞳孔区的较大翼状胬肉40眼随机分成两组,一组行翼状胬肉切除、角膜缘干细胞移植术联合全角膜羊膜覆盖术(羊膜组),另一组行胬肉切除和角膜缘干细胞移植术后配戴绷带型角膜接触镜(绷带镜组),每组各20眼。比较两组患者手术时间,以及术后第1、3d,1、3wk眼部舒适程度和角膜愈合情况与随访复发情况等。

结果：平均手术时间：羊膜组为61.4±5.2min,绷带镜组为34.5±2.7min,绷带镜组手术时间明显缩短,两组差异有统计学意义(P<0.05)。两组患者的眼部舒适度在术后第1d无明显差异,但在术后第3d和术后1wk,绷带镜组患者的眼部舒适度明显优于羊膜组(P<0.01),至术后3wk时两组间差异无统计学意义(P>0.05)。术后3wk时两组患者的角膜愈合率评分分别为0.85±0.18分和1.15±0.18分,两组差异无统计学意义(P=0.25)。羊膜组有1眼胬肉复发。

结论：在侵及角膜的较大翼状胬肉治疗中,胬肉切除和角膜缘干细胞移植术后联合全角膜羊膜覆盖或术后配戴绷带型角膜接触镜均有助于缓解眼部不适症状和促进角膜创面修复,使用绷带型角膜接触镜患者更舒适,治疗更便捷。     

翼状胬肉切除联合自体角膜缘结膜移植术后绷带镜的应用

目的：探讨翼状胬肉切除联合自体角膜缘结膜移植术后应用角膜绷带镜的临床效果。

方法：随机对照临床试验。选取2017-11/2018-10在我院眼科接受手术治疗的原发性翼状胬肉患者92例92眼,按随机数字表法分为角膜绷带镜组和弹性绷带组,每组各46眼。两组患者均接受翼状胬肉切除联合自体角膜缘结膜移植术,术毕角膜绷带镜组患者配戴角膜接触镜,弹性绷带组患者在术毕结膜囊内涂红霉素眼膏,弹性绷带包眼。裂隙灯显微镜观察术后第1、4、7d角膜上皮创面,对角膜上皮愈合情况进行评分; 运用评价视觉模拟评分法评价术后7d疼痛情况; 运用问卷评分法评价术后7d舒适情况(包括异物感、流泪)。

结果：术后第1d和第7d两组患者角膜上皮愈合情况无明显差异,而术后第4d角膜绷带镜组患者角膜上皮愈合优于弹性绷带组(P<0.05)。此外,角膜绷带镜组患者术后7d疼痛感评分低于弹性绷带组,眼部舒适度评分高于弹性绷带组(P<0.05)。

结论：角膜绷带镜不仅可以有效促进角膜上皮愈合,还可以有效减轻疼痛,提高眼部舒适感。     

Comparative clinical performance of two silicone hydrogel contact lenses for continuous wear

Background Silicone hydrogel soft contact lenses are now available for use on a 3O‐day continuous wear basis. The aim of this study was to compare the clinical performance of two such lenses. Methods: In a single‐centre, randomised, subject‐masked, two‐period crossover study, 30 subjects wore a pair of Purevision lenses (Bausch & Lomb) and a pair of Focus Night & Day lenses (CIBA Vision), alternately, for successive eight‐week periods. Assessment was made of lens fit and surface characteristics, logh4AR visual acuity, ocular response and subjective reaction. Results: Lens fit, deposition and post‐lens debris were similar for the two lens types. High contrast visual acuity was statistically significantly better for the Purevision lens, as was the subject‐reported quality of vision, although these differences were not considered clinically significant. For both lenses, limbal and conjunctival redness reduced throughout the duration of the study, whereas there was a slight increase in the overall amount of corneal staining. The incidence of mucin balls peaked four weeks after commencing lens wear and began to decline thereafter; more mucin balls were noticed in subjects wearing Focus Night & Day lenses. No differences between the lenses were observed for any other biomicroscopic signs. Conclusions: This study demonstrates similar clinical performance with the two silicone hydrogel lenses evaluated. We believe that, with careful monitoring, both of these newgeneration lenses can be prescribed for continuous wear.     

Comparison of effectiveness of silicone hydrogel contact lens and hydrogel contact lens in patients after LASEK

AIM: To conduct a comparative study of effectiveness of silicone hydrogel contact lens and hydrogel contact lens, which are used in patients after laser-assisted subepithelial keratomileusis (LASEK). METHODS: Sixty-three patients (121 eyes) with a spherical equivalent ≤-5.0 D were chosen after undergoing LASEK in 2012 at Guangdong General Hospital. They were randomly divided into 2 groups. The silicone hydrogel group included 32 cases (61 eyes) that wore silicone hydrogel contact lenses for 4-6d after the operation, while the hydrogel group included 31 cases (60 eyes) who wore hydrogel contact lenses for 4-6d after the operation. Patients’ self-reported postoperative symptoms (including pain, photophobia, tears, and foreign body sensation) were evaluated. The healing time of the corneal epithelium, the visual acuity of patients without contact lens after epithelial healing, and the incidence of delayed corneal epithelial shedding were also assessed. The follow-up time was 1mo. RESULTS: Postoperative symptoms were milder in the silicone hydrogel group than in the hydrogel group. There were significant differences in pain, foreign body sensation, and photophobia between the 2 groups (P<0.05), although there was no significant difference in postoperative tearing (P>0.05). The healing time of the corneal epithelium in the silicone hydrogel lens group was markedly shorter than that in the hydrogel group (4.07±0.25 vs 4.33±0.82d, t=2.43, P=0.02). Visual acuity without contact lenses after healing of the corneal epithelium was better in the silicone hydrogel group compared with the hydrogel group (χ2=7.76, P=0.02). There was no significant difference in the occurrence of delayed corneal epithelial shedding between the 2 groups (P>0.05). CONCLUSION: Patients with LASEK using silicon hydrogel contact lenses had less discomfort and shorter corneal epithelial healing time compared with those using hydrogel contact lenses, suggesting that silicon hydrogel contact lenses may be considered to be a better choice of bandage contact lens after LASEK.     

Comparison of efficacy of two different silicone hydrogel bandage contact lenses after T-PRK

AIM:To compare the efficacy between two different silicone hydrogel bandage contact lenses after transepithelial photorefractive keratectomy(T-PRK).METHODS:In this randomized controlled trial,a total of 89 patients(178 eyes) who underwent T-PRK at the Qingdao Eye Hospital from October to December 2019 were selected.One random eye wore a Senofilcon A bandage contact lens after surgery,and the other eye a Balafilcon A bandage contact lens.Pain scores,uncorrected visual acuity(UCVA),spherical equivalent(SE),corneal epithelial healing status,epithelial thickness,bandage lenses deposits,lenses movement,and ocular surface conditions were measured and compared.RESULTS:There were no differences between the two groups in UCVA,SE,corneal epithelial healing status,corneal epithelial thickness,tear river heights and tear film rupture time at each follow-up visit.However,postoperative pain scores in the Senofilcon A group were significantly lower than those of the Balafilcon A group(F_intergroups=67.833,P<0.001;F_time=383.773,P<0.001;F_interaction=57.344,P<0.001).The duration of pain in eyes in the Senofilcon A group was shorter than that of the Balafilcon A group(t=-3.326,P=0.001).The surface deposition scores and movement scores of Senofilcon A bandage lenses on the first and fourth days after surgery were lower than those of Balafilcon A bandage lenses(Z=-5.385,-6.782,P<0.001;Z=-8.336,-8.906,P<0.001).CONCLUSION:Both Senofilcon A and Balafilcon A bandage lenses have good efficacy after T-PRK.Senofilcon A lenses are associated with less pain and more comfort compared to Balafilcon A.     

硅水凝胶角膜接触镜在乙醇法-和机械法-激光上皮下角膜磨镶术术后的应用

目的评价Galyfilcon A硅水凝胶软性角膜接触镜(acuve advance)作为乙醇法-准分子激光上皮下角膜磨镶术(laser subepithelial keratomileusis,LASEK)和机械法-激光上皮下角膜磨镶术(epi-laser in situ keratomileusis,epi-LASIK)术后绷带式接触镜应用的临床安全性和有效性。方法31例(58眼)行LASEK或epi-LASIK的患者参与了本前瞻性临床研究,其中9例双眼行LASEK手术者作acuve advance和月抛型镜片的对照研究,其余22例均使用acuve advance镜片。根据角膜上皮愈合的情况,镜片连续配戴3 d或7 d。在术后第1天、第3天和第7天,观察镜片的中心位置、移动度、湿润度和沉淀物,在裂隙灯下对角膜缘充血和角膜上皮水肿情况进行评分,并由患者对其不适感(疼痛和异物感)行主观量化评分。结果Acuve advance的镜片中心位置、移动度、湿润度均良好,常见散在沉淀物。大部分患者疼痛感无或很轻,而异物感是主要症状。与月抛型镜片相比,术后第1天和第3天的戴acuve advance者异物感更轻(Z=2.72,P=0.007;Z=2.37,P=0.018);戴acuve advance者术后第1天的疼痛感更轻(Z=2.60,P=0.009);戴acuve advance者术后角膜缘充血与角膜上皮水肿也略轻,但差异无显著性。未发生严重并发症。结论Galyfilcon A硅水凝胶软性角膜接触镜作为LASEK和epi-LASIK术后绷带式接触镜应用是安全有效的,与月抛型镜片相比,更适合于长期配戴。     

A 6-month follow-up of successful refits from daily disposable soft contact lenses to continuous wear of high-Dk silicone-hydrogel lenses

PURPOSE: To compare, in routine optometric practice, the outcome of keeping successful soft contact lens (SCL) wearers in their lenses to re-fitting them with continuous wear of silicone hydrogel (SiH) lenses. METHODS: Forty-nine successful daily disposable lens wearers were recruited; 19 continued to wear daily SCLs and 30 were refitted with high-Dk SiH lenses on a 30-day/night schedule. Patients were assessed at baseline, 3 and 6 months by slit lamp examination along with the Efron grading scales, and central corneal thickness (CCT) and the corneal endothelium were assessed by non-contact specular microscopy. RESULTS: No substantial changes in subjective vision, refraction, visual acuity or overall lens comfort occurred for those completing the study, although five SiH lens wearers did discontinue due to reduced comfort, eyelid problems or seasonal allergy. Contact lens induced peripheral ulcers (CLPU) were observed in three patients in the first 3 months in the SiH lens group and these were also discontinued. Over the 6 month period, a complete set of records was obtained for 16 in each group. For those completing the study, lens dryness scores were variable, but there was a slight improvement in favour of SiH lenses. Small, but statistically significant, reductions in corneal staining, bulbar hyperaemia, and limbal neovascularisation in favour of the SiH lenses were also evident but mainly because of further increases in the daily lens wearers. Contact lens induced papillary conjunctivitis (CLPC) and corneal endothelial polymegethism were mild to moderate and showed slight increases in the daily lens wearers at 6 months. CONCLUSIONS: The present studies confirm that the continuous wear of SiH lenses for up to 30 days can be considered as an alternative to daily disposable soft lens wear, but is not suitable for everyone.     

The comparative clinical performance of a new polyhexamethylene biguanide- vs a polyquad-based contact lens care regime with two silicone hydrogel contact lenses

PURPOSE: To compare the clinical performance of a new polyhexamethylene-biguanide (PHMB)- vs a polyquad-based contact lens care regime with two silicone hydrogel contact lenses. METHODS: This study was a randomised, controlled and investigator-masked (to the lens regimen) clinical study where the clinical performance of two multipurpose contact lens solutions was compared at a single site. Forty-one existing contact lens wearers were recruited and fitted randomly with either galyfilcon A or lotrafilcon A contact lenses. Subjects wore the same lens type for a period of 2 months but used a different care regime (PHMB- and polyquad-based) in a crossover manner, each for a period of 1 month. The primary outcome measure was the difference in corneal staining. Corneal staining was graded in five different locations: central, superior, inferior, temporal and nasal. Measurements of conjunctival redness, limbal redness, conjunctival staining and papillary conjunctivitis were also carried out throughout the study. Biomicroscopic measures were graded using the Efron grading scales. A variety of symptoms were also measured using a visual analogue scale. RESULTS: There was no statistically significant difference in overall corneal staining between lens types (p = 0.16) or care regimens (p = 0.60). Central corneal staining was significantly greater for the polyquad-based care regimen when compared with the PHMB-based care regimen (p = 0.04). Lotrafilcon A lenses showed greater superior corneal staining (p = 0.0004) and papillary conjunctivitis (p = 0.02), and lower comfort on insertion (p = 0.03) when compared with galyfilcon A lenses regardless of the care regime used. There were no statistically significant differences in the other biomicrosopic signs and symptoms between the lens types and the care regimes. CONCLUSIONS: Both care regimes performed in a similar clinical manner and are valid for use with the two silicone hydrogel contact lenses used in this study.     

两种绷带镜在糖尿病患者玻璃体视网膜手术中应用后对角膜的影响

目的:观察不同类型的角膜绷带镜在玻璃体视网膜手术中应用后对糖尿病患者角膜的影响.方法:前瞻性非随机对照研究.将符合增殖性糖尿病视网膜病变、拟行玻璃体视网膜手术的患者69例69眼按照患者意愿分为两组.A组36例36眼,术中使用直径为13.8 mm角膜绷带镜覆盖于角膜表面,非接触广角镜下实施玻璃体切割联合眼内填充术,手术结束后去除绷带镜;B组33例33眼,同法使用直径为14.0 mm角膜绷带镜,以相同方式实施手术.术前和术后1、2、3、7d进行裂隙灯显微镜、角膜荧光素钠染色检查.术前和术后7d行角膜内皮细胞计数、角膜厚度测量.结果:术前两组患者角膜荧光素钠染色阳性检出率分别为42%和42%(x2=0.004,P=0.949).术后第1、2、3、7d两组患者角膜染色阳性率分别为47%和45%(x2=0.022,P=0.883),44%和45%(x2=0.007,P=0.933),44%和42%(x2=0.029,P=0.886),42%和39%(x2=0.037,P=0.848);两组患者间各时间点角膜上皮阳性检出率比较,差异无统计学意义(P>0.05).术前和术后7d时,A组角膜内皮细胞计数分别为2779.25±329.55、2777.14±331.17个/mm2,差异无统计学意义(t=0.551,P=0.585);B组角膜内皮细胞计数分别为2678.61±335.64、2672.45±336.25个/mm2,差异无统计学意义(t=1.774,P=0.086).术前和术后7 d时A组角膜厚度分别为519.25±23.42、542.03±25.94μm,差异有统计学意义(t=-6.854,P<0.001);B组为525.64±20.97、551.33±27.87μm,差异有统计学意义(t=-7.204,P<0.001).结论:糖尿病患者玻璃体视网膜手术中使用不同类型角膜绷带镜,手术前后角膜上皮完整性无差异.不同类型的绷带镜均可有效保护角膜上皮,术中可保持良好的角膜透明性.     

Evaluation of the safety and efficacy of therapeutic bandage contact lenses on post-cataract surgery patients

AIM: To evaluate the safety of therapeutic bandage contact lens for post-cataract surgery patients and to illustrate its efficacy on post-operative comfort and tear-film stability. METHODS: A total of 40 participants were recruited and randomly divided into two groups. Group one was instructed to wear bandage contact lenses for a week and use antibiotic eye drops for a month since the first day after surgery. Group two received sub-conjunctival injection of tobramycin and was asked to wear eye pads on the first day after surgery and then were instructed to use antibiotic eye drops as the first group did. Ocular surface disease index (OSDI) questionnaire, slit-lamp microscope examination of tear break-up time (TBUT), corneal fluorescein score (CFS), tear meniscus height (TMH) together with anterior segment optical coherence tomography (AS-OCT) and corneal topography were evaluated preoperatively and postoperatively. RESULTS: The subjective feeling (P=0.004), TBUT (P<0.001) and TMH (P=0.02) post-surgery had improved in patients who used bandage contact lenses compared with those who did not at 1wk post-surgery. Until three month postoperatively, the comfort degree (P=0.004) and TMH (P=0.01) of group two were still worse than group one. Moreover, TBUT (P<0.001) and CFS (P=0.004) of the group with eye pads got worse than the results before, whereas the group with bandage contact lenses recovered to normal. None of these patients had infections or other complications. CONCLUSION: Wearing therapeutic bandage contact lens after cataract surgery, compared with traditional eye-pads, is a safe method to improve tear-film stability and reduce post-operative discomfort without hindering corneal incision recovery.     

接触镜致角膜病变的临床研究

目的 分析研究长期戴矫正近视的接触镜引起的角膜病变。方法 对32例(64眼)曾长期戴软性角膜接触镜(观察组)和38例(76眼)戴框架眼镜(对照组)要求行LASIK手术的近视者进行术前的角膜形态学检查、裂隙灯检查及泪液检查。结果 长期配戴接触镜所致角膜新生血管18例36眼,占56.25％,眼干燥症10例20眼,占31.25％。对角膜中央内皮测量进行两组间t检验,P<0.05,差异有显著意义。结论 戴角膜接触镜致角膜病变的发病率高于戴框架眼镜(对照组)者,角膜中央内皮细胞密度明显低于对照组者。     

硅水凝胶镜片作为绷带型角膜接触镜的应用前景

角膜接触镜除了能够矫正屈光不正外,还能够作为绷带型角膜接触镜（绷带镜片）用于眼表疾病的治疗,大多数绷带镜片需要连续过夜配戴以实现良好的治疗效果,而传统的水凝胶镜片由于透氧性能的不足可能导致角膜缺氧,因此有高透氧性能的硅水凝胶镜片是更为理想的绷带镜片选择。了解硅水凝胶镜片作为绷带镜片在角膜病变、角膜屈光手术后以及作为药物载体的应用情况,将有助于制定绷带镜片治疗措施的个性化方案。     

The influence of lens conditioning on signs and symptoms with new hydrogel contact lenses

Background: Daily disposable contact lenses are considered to be the pinnacle of safe contact lens wear, yet it has been suggested that it takes some period of wear for the lens surface to reach optimal compatibility with the ocular surface. This study assesses the influence of brief treatment with a conditioning drop on the ocular response to new contact lenses over a single day of wear. Methods: The study was a single‐masked, paired (contralateral) comparison of the signs and symptoms with wear of new Acuvue 2 contact lenses pretreated with a conditioning agent containing carboxymethylcellulose (carmellose, CMC) against new lenses inserted directly from the blister pack. Sixty‐one subjects participated in the study, of whom 59 were considered eligible for data analysis. Subjects were also divided into symptomatic and asymptomatic lens wearers based on their overall comfort level in lens wear. Symptoms and signs were recorded at lens delivery and following eight hours of wear. Results: A set of slitlamp signs, comprising corneal staining (p < 0.05), limbal redness (p < 0.05), bulbar conjunctival hyperaemia (p < 0.05), bulbar conjunctival staining (p < 0.01) and palpebral conjunctival redness (p < 0.05) showed small but statistically significant (p < 0.05) end‐ofday mean values in favour of the lens that was conditioned with the rewetting agent. These data were supported by the proportion of subjects showing lower gradings with conditioned lenses versus unconditioned lenses, as follows: corneal staining (35 per cent versus 12 per cent, p <0.05), limbal redness (43 per cent versus 22 per cent, p < 0.05), bulbar conjunctival hyperaemia (50 per cent versus 15 per cent, p < 0.05), bulbar conjunctival staining (46 per cent versus 30 per cent, p < 0.1) and palpebral conjunctival hyperaemia (28 per cent versus 17 per cent, NS). For those subjects reporting symptoms with lens wear (n = 12), there was a statistically significant (p < 0.05) preference in terms of comfort as a result of preconditioning. Conclusions: The results of the investigation suggest that use of a conditioning agent can provide a more physiologically suitable environment for a new lens, thereby reducing the clinical signs associated with lens discomfort. The protocol used here, which is based on a statistical paradigm using standard pictorial grading scales, allows high sensitivity in detecting small changes in ocular parameters.     

纤维蛋白胶联合绷带型角膜接触镜在复发性翼状胬肉手术中应用

目的探讨纤维蛋白胶联合绷带型角膜接触镜应用于复发性翼状胬肉手术的临床效果。方法对2013～2015年期间我院复发性翼状胬肉60例（63只眼）行翼状胬肉切除联合带自体角膜缘干细胞的结膜移植术,随机分为试验组（ A）应用纤维蛋白胶联合绷带型角膜接触镜、对照组（ B）应用缝线法联合绷带型角膜接触镜,观察手术时间、术后眼部症状、愈合、复发率、不良反应,评价其临床疗效。结果2组间比较手术时间、术后眼部症状、愈合、复发率及不良反应A组均优于B组。结论对于复发性翼状胬肉,应用纤维蛋白胶联合绷带型角膜接触镜手术时间、术后症状、愈合、复发率、不良反应更优,具有广泛的临床实用价值。     

A comparative study of biweekly disposable contact lenses: silicone hydrogel versus hydrogel

Background: Our aim was to compare the clinical performance of a biweekly (second generation) silicone hydrogel lens and a biweekly hydrogel lens worn for daily wear modality. Methods: We used a double‐masked study, in which non‐presbyopic, asymptomatic and adapted soft lens wearers were recruited. Subjects wore a silicone hydrogel lens in one eye and a hydrogel lens in the other (lens types and eyes were randomly assigned) for one month. Lenses were replaced every two weeks. Contact lens fitting, pre‐lens tear film thinning time, vision, corneal integrity and lens deposits were assessed before and every fortnight after delivery of new lenses. A questionnaire was used to compare the subjective performance of the two lens types. Results: Thirty of the 33 subjects completed the study. There were no significant differences in lens fitting (centration and movement), pre‐lens tear film thinning time, vision or corneal integrity between the two lens types. Statistically, there was no significant difference in lens deposits between the two lens types but silicone hydrogel lenses tended to have more Grade 3 to 4 lipid deposits than hydrogel lenses. Subjects found no significant differences between the two lens types in terms of vision and comfort. Preference for silicone hydrogel lenses increased from 33 at the first after‐care visit to 50 per cent at the second after‐care visit. Conclusion: This short‐term study demonstrates that the performance of silicone hydrogel and hydrogel lenses is comparable but the former tends to build up more lipid deposits than the latter. We did not find better performance in terms of ocular integrity of silicone hydrogel lenses compared to the hydrogel lenses, probably because the subjects were adapted asymptomatic contact lens wearers before commencing the study. Contact lens wearers having hypoxia‐related problems are likely to benefit from using silicone hydrogel lenses, as these lenses provide at least three times more oxygen than conventional hydrogel lenses.     

Poorly fitting soft lenses affect ocular integrity.

PURPOSE: The purpose of this study was to determine whether borderline fitting soft lenses have a greater effect on ocular physiology than well fitting lenses. METHOD: The study was a retrospective analysis of data from seven soft lens clinical studies. The results of 63 eyes wearing borderline fitting lenses (31 tight and 32 loose fittings) were evaluated and compared with control eyes wearing optimally fitting lenses. Tight and loose lens fittings were defined as those showing tightness on push-up of > or =65% and < or =35%, respectively. An optimally fitting lens was defined as one showing tightness on push-up in the range 45-50% and decentration less than 0.7 mm. Slit lamp findings at the 1-month follow-up visit were compared. RESULTS: There was a significantly greater level of corneal staining among the tight lens wearing group than the controls (P=0.001); 68% of eyes wearing tight lenses showed staining as compared with 42% of eyes wearing well fitting lenses. There was also a greater level of conjunctival staining among tight lens wearing eyes but no significant difference in bulbar or limbal hyperemia. The loose lens wearing eyes showed a higher level of corneal staining: 69% vs 39% (P=0.04). In addition, the loose lens wearing eyes showed a higher level of bulbar (P=0.03) and limbal hyperemia (P=0.006). From supplementary analysis of 408 lens fittings, the incidence of corneal staining was found to increase with increasing tightness or looseness of fit. CONCLUSION: The results show that corneal staining and other physiological effects of soft lens wear vary with the quality of lens fit suggesting that practitioners should be less tolerant of sub-optimal fitting soft lenses.     

软性角膜接触镜与透气性硬性角膜接触镜对像差的影响

目的 分析配戴软性角膜接触镜、透气性硬性角膜接触镜（rigid gas-permeable contact lens,RGP）患者波前像差及角膜地形图在配戴前后的变化,探讨角膜接触镜对人眼屈光系统成像质量的影响.设计前瞻性随机对照临床研究.研究对象近视眼患者41例（80眼）.方法 软镜组20例（40眼）配戴软性角膜接触镜,RGP组21例（40眼）配戴RGP镜片,患者治疗前后作角膜地形图及波前像差检查,随访观察12个月.主要指标观察配戴接触镜治疗前后角膜地形图及波前像差的变化.结果 软镜组患者治疗后角膜表面规则指数（surface regularityindex,SRI）及角膜表面非对称指数（surface asymne-tryindex,SAI）有所增加,而RGP组SRI及SAI轻度下降;戴镜条件下,两组的整体波前像差（软镜组：0.58;RGP组：0.91）均低于治疗前裸眼的整体波前像差（软镜组：0.71;RGP组：1.21）;配戴后裸眼条件下,RGP组整体像差低于治疗前,且以低阶像差下降为主,而软镜组整体像差高于治疗前,各阶像差呈均匀上升趋势.结论 良好配适状态下的角膜接触镜均可使像差减小,使患者获得优质的光学矫正.