角膜接触镜配戴者眼部及系列用品微生物学调查

１９９１年～１９９３年期间，对软质角膜接触配戴者眼部及系列用品污染微生物进行调查。结膜囊带菌阳性率戴镜前为３３．６％，戴镜后为２２．５％。Ｐ〈０．００５。戴镜前结膜囊细菌以革兰氏阳性菌为主，戴镜后菌群发生了变化，革兰氏阴性菌所占比率与革兰氏阳性菌接近，戴镜者系列用品２８．２％～４０．６％，被微生物污染，戴镜前，后结膜囊菌群变化与接触镜系列用品污染密切相关，检查了３２例戴镜并发角膜感染病例，从眼病变     

抛弃型水凝胶接触镜的细菌定植

目的:确定抛弃型水凝胶接触镜及其护理液细菌定植的比率,并确定污染的病原体。方法:按目的抽样进行横断面研究。从马来西亚Sains大学健康校园的本科学生接触镜配戴者中收集100片水凝胶接触镜。所有的镜片和护理液均送微生物培养和革兰氏染色。结果:大多数的研究参与者为女性(98%)。平均年龄21.36±1.63岁。41片接触镜(82%)呈现阳性细菌定植,32%的护理液可见阳性细菌定植。最常见的病原体是凝固酶阴性葡萄球菌、金黄色葡萄球菌和链球菌,而在接触镜中能更频繁地分离出假单胞菌和沙雷氏菌。结论:配戴接触镜有导致镜片和护理液细菌定植的潜在危险。建议在镜片护理和配戴过程中采取最大程度的预防措施并严格遵守卫生做法。     

青少年角膜塑形镜配戴者结膜囊及镜盒菌群研究

目的研究配戴角膜塑形镜对青少年结膜囊菌群的影响,以及角膜塑形镜存储盒带菌情况。方法实验研究。分别对101名配戴角膜塑形镜（配戴组）和110名未配戴角膜塑形镜青少年（对照组）进行结膜囊细菌培养,并对158个角膜塑形镜存储盒进行细菌培养。所有标本置于37 ℃恒温箱中培养48 h后统计培养阳性率。数据比较采用卡方检验。结果对照组结膜囊培养菌株68株,阳性率为30.9%;配戴组结膜囊培养菌株59株,阳性率为29.4%;2组结膜囊细菌培养阳性率差异无统计学意义（χ²=0.12,P>0.05）。角膜塑形镜存储盒细菌培养菌株72株,阳性率为45.6%。2组研究对象结膜囊和镜盒菌群培养阳性率首位均为表皮葡萄球菌。结论配戴角膜塑形镜不会提高青少年结膜囊带菌率,镜片及镜盒的清洁可降低镜片污染率。     

配戴角膜接触镜后的角膜地形图分析

配戴角膜接触镜可引起角膜形态的改变,停戴接触镜后,角膜形态会逐渐恢复,其恢复时间还与配戴镜片的种类、配戴方式、配戴时间的长短、个体差异等均有相对的关系;配戴接触镜后还可以引起角膜厚度的改变.角膜地形图可以全面客观地评估接触镜配戴者的角膜形态改变,尤其是对接触镜配戴者进行屈光治疗时,可以适当掌握手术时机,同时,可用于鉴别早期圆锥角膜及指导接触镜的更佳验配.     

角膜接触镜配戴者的戴镜行为及认知的调查分析

目的通过对角膜接触镜经验配戴者进行问卷调查,了解配戴者的戴镜行为、护理习惯以及对角膜接触镜医疗属性的认知程度,探讨提高配戴者戴镜舒适度和安全性的可行性对策。方法调查研究。在上海、北京、广州、深圳、成都和杭州6个城市42家大型眼镜店对角膜接触镜经验配戴者进行调查。调查问卷共28题（分6部分内容）,包括：①配戴者基本资料和戴镜史;②当前戴镜行为;③日常护理习惯;④眼科检查和随访复查;⑤对角膜接触镜的认知评估;⑥镜片验配和影响因素。对相关调查数据进行X^2检验。结果本调查共回收到504份有效问卷。①受访者中女性439名（87．1％）,男性65名（12．9％）,年龄为19—42岁,平均（27．8±7．3岁）;戴镜经验为6个月～12年,平均为（6-3±5．2）年。②6．2％（31／504）受访者戴日戴型镜片过夜,2周和1个月更换型配戴组比日抛组、3-6个月更换组以及〉6个月更换组更遵循更换周期．差异具有统计学意义（X^2=12．32、57．52、45．91,P〈O．01）。③73．O％（368／504）受访者在操作镜片前洗手,54．0％（272／504）受访者有揉搓清洁镜片,38．1％（192／504）受访者使用护理液冲洗镜片。④67．1％（338／504）受访者从未主动随访复查,50．1％（207／413）和37．8％（68／180）受访者对戴镜期间出现的不舒适和眼病曾采用不恰当的处理方法。⑤17．1％（86／504）受访者知晓角膜接触镜为医疗用品,超过6成受访者对角膜接触镜有不同程度的认知错误。⑥63．1％f318／504）受访者将接触镜的价格作为选择镜片的首要影响因素。结论很多配戴者在角膜接触镜使用中存在安全隐患．原因可能是对角膜接触镜医疗属性认知不足,眼保健意识匮乏等。应该普及角膜接触镜配戴护理相关的公众教育,提升验配人员的专业水平以及加强初戴者的安全、规范使用宣教,以提升角膜接触镜的配戴安全性。     

角膜接触镜的并发症及其对策

随着角膜接触镜的广泛应用,眼部并发症也日益增多.为了减少或避免此并发症,作者根据多年的临床实践及有关文献,就此问题综述于后,以引起同道及角膜接触镜配戴者的重视.(一)眼部并发症1.角膜溃疡:角膜溃疡是戴角膜接触镜引起的最严重的眼部并发症,如不及时治疗,有失明危险.角膜溃疡可由细菌、真菌、病毒、原虫等引起,其中以绿脓杆菌感染最常见.国外报道戴接触镜引起的角膜溃疡中,绿脓杆菌性者占75%,国内报道75例,其次为葡萄球菌、肺炎球菌及溶血性链球菌引起者,真菌所致者少见,同外报道仅占4%,病毒、棘阿米巴性者国内尚未见报道.     

共焦显微镜诊断双眼角膜塑型镜相关性阿米巴角膜炎1例

患者，男性，20岁，学生，因过夜配戴角膜塑型镜后出现双眼红、疼痛、视力下降半个月，于2006年12月5日来我院就诊。患者为华裔加拿大人，半年前来北京读书，配戴角膜塑型镜已4年，每天用护理液清洗镜片前均用自来水清洗。来我国后护理方式没有改变。     

新型长戴型角膜接触镜的临床观察

目的 :观察新型长戴型角膜接触镜———PureVi sion(PV)的临床效果及其安全性。方法 :33例 (6 6眼 )隐形眼镜配戴者平均屈光度为 (- 4 .36± 1.5 4 )D ,配戴PureVision连续配戴型隐形眼镜 (简称PV) ,共连续配戴 1个月后更换镜片 ,观察时间为 2个月。配戴前检查视力、屈光度 ,裂隙灯检查眼前段 ,做镜片配适评估并行问卷调查做主观评价。结果 :眼前段检查显示 ,第 1个月连续配戴后 ,角膜缘充血、角膜新生血管、球结膜充血、巨乳头结膜炎、角膜荧光素染色等程度与配戴前相同的患者所占的比例 ,分别是 88.9%、96 .3%、6 4 .8%、5 0 %及 5 7.4 %。第 2个月连续配戴后 ,以上指标观察显示 ,与配戴前相同的患者比例分别是 95 .8%、87.5 %、85 .4、70 .8%及 5 6 .3%。配戴前患者均无角膜水肿 ,而连续配戴 1个月后角膜轻度水肿者占 14 .8% ,第二个月连续配戴则无角膜水肿发生。配戴者的主观评价显示 ,PV镜片的舒适度、清晰度以及镜片的整体满意度方面均高于以往配戴的镜片。结论 :新型长戴型角膜接触镜———PureVision的配戴者对该镜片的主观评价满意度较高 ,连续配戴后未见严重并发症的出现     

武汉市大学生对角膜接触镜认知程度和使用效果的调查

目的 了解武汉市大学生群体对角膜接触镜的认知程度和使用效果.方法 在武汉市高校采用随机抽样法进行问卷调查,共762例,分为未使用角膜接触镜组(A组652例)和使用过角膜接触镜组(B组110例).对A组仅调查其认知程度,对B组调查认知程度和使用效果.结果 B组对角膜接触镜基本知识的正确认知率(64例,58.18%)高于A组(82例,12.58%),差异有统计学意义(X2=126.38,P＜0.05).在所有调查群体中79.09%未发生严重不适感,88.18%每天清洗镜片,80.91%按时更换镜片,44.55%按期更换镜盒.结论 大学生对角膜接触镜正确认知程度普遍不高,但已使用者的使用效果较满意.     

彩色角膜接触镜规范验配白皮书

软性接触镜自问世以来,以其良好的视觉质 量与舒适度,于20世纪70年代开始在临床上大规 模应用,至2011年全球有超过1.4亿人口配戴接触 镜[1-2],且呈逐年递增趋势。《2018—2023 年中国 隐形眼镜市场分析与投资前景研究报告》[3]显示, 2010—2017年期间,中国接触镜消费额平均增长率 为17.6%,而彩色角膜接触镜的复合年均增长率远 高于这一数值,在整个接触镜行业中占据的份额逐 年增高。《天猫隐形眼镜行业人群洞察白皮书》[4]显 示,彩色隐形眼镜于2019年、2020年、2021上半 年的商品交易总额市场增速分别达到20%、45%、 83%。 彩色隐形眼镜或彩色角膜接触镜简称“彩 片”,在提高视觉效果的同时,还满足了爱美人士 的需求。随着材料、设计和生产工艺的不断革新, 彩片有各种样式、设计、更换周期和配戴方式,也 受到了越来越多近视人群与美妆用户的青睐。彩 片是软性接触镜中的一种特殊类型,也被国家食品 药品监督管理总局归类为要求管理最严格的三类 医疗器械。由于购买渠道方便、市场上彩色接触镜 质量参差不齐,各机构验配流程不同、配戴人群护 理意识参差不齐,与彩片相关的眼健康问题屡见不 鲜[5-6]。不规范、不卫生的操作有着巨大的潜在风险,因此彩片的配戴及护理的规范化亟需引起重视。 为了增强彩片配戴者爱眼护眼的眼健康意识,提高配戴者的依从性,规范彩片配戴和护理流程,保障彩片配戴者的眼健康,通过对配戴者、视光医生及视光从业人员的访谈,充分了解国内彩片的销售和配戴者使用现状的基础上,查阅文献,中国眼谷&moody角膜接触镜技术创新研究院邀请国内部分眼视光学专家、角膜病学专家及材料学专家共同商讨、起草和编写了《彩色角膜接触镜规范验配白皮书》初稿,经过数次讨论和修改后定稿,达成以下共识。 1  配戴者的眼健康标准定义 2  彩片健康配戴的基本要求 2.1 矫正视力清晰 2.2 配戴周期合理 2.3 配戴舒适 2.4 具有防紫外线功能为佳 2.5 材质优良 2.6 安全无毒 3  彩色接触镜验配流程 3.1 病史采集 3.2 配戴前检查 3.2.1 视力和屈光度检查 3.2.2 裂隙灯显微镜眼前节检查 3.2.3 角膜曲率 3.3 镜片选择 3.3.1 镜片透氧量 3.3.2 配戴舒适度 3.3.3 对干眼者的建议 3.3.4 对散光者的建议 3.4 配戴和评估 3.5 确定处方 3.6 配戴者教育 3.6.1 软镜摘戴指导 3.6.2 软镜护理指导 3.6.3 镜片护理的注意事项 3.6.4 强调镜片使用注意事项 3.7 定期随访     

Microbial contamination of contact lenses and lens care accessories of soft contact lens wearers (university students) in Hong Kong

PURPOSE: This study aimed to examine the rates of microbial contamination, and identify contaminants associated with contact lenses and lens care accessories used by a group of young contact lens wearers. METHODS: Collected contact lenses, lens cases, and lens care solutions were studied by bacterial culture. Contamination rates of these samples were recorded and compared with those reported in previous studies. RESULTS: Of the samples tested, 9% of lens extracts, 34% of case extracts and 11% of solution samples were contaminated with ocular pathogenic microorganisms. Serratia spp., Staphylococcus aureus and coagulase-negative staphylococci were the most common microorganisms isolated. Lens cases were the most frequently contaminated item. Lens cases also yielded the widest range of bacterial isolates. Contact lenses used by occasional wearers were associated with a higher contamination rate. Using either saline or multipurpose solution to rinse lenses before use appeared to be effective in reducing incidence of contamination. CONCLUSION: Our findings demonstrate that contact lenses and lens care accessories are not well maintained by contact lens wearers. Regular reviews and reinforcement of lens care procedures for the usage and care of contact lenses and lens care accessories is therefore important and essential.     

Acute keratitis and contamination of contact lens care systems with Bacillus cereus

Two patients, both contact lens wearers, were treated for acute keratitis in both eyes. Routine microbiologic tests done for all four eyes confirmed merely the presence of Staphylococcus epidermidis in the conjunctival flora; neither fungi nor any viruses were detected on the patients' corneas. However, the contact lens soaking solutions were contaminated with a large number of microorganisms, including above all--or solely--Bacillus cereus. Two of the contact lenses used were also colonized by fungi of the genus Rhodotorula, Cryptococcus albicans and Wangiella dermatidis. The acute inflammation was treated quickly and effectively in all cases by specific antimicrobial therapy. Bacterial contamination of lens care systems is well known as a potential cause of keratitis in contact lens wearers. Although the clinical importance of Bacillus cereus in ocular surface pathology is still unknown, the cases reported here indicate that this microorganism may be of pathological significance in lens care systems. The authors therefore recommend including the lens care systems in routine bacteriologic tests in all cases of corneal infection where the patient wears contact lenses.     

Ocular bacterial flora in contact lens wearers

In this study, ocular bacterial flora was determined for 126 healthy subjects before and after wearing soft contact lenses for 3, 6, and 9 months. The lenses were polyhydroxyethyl methacrylate with a water content of 55%. The care system used polyaminopropyl biguinide as the preservative.Our results indicate the presence of microorganisms such as Staphylococcus epidermidis (40.03%), Corynebacterium xerosis (2.78%), Corynebacterium acne (0.79%), and Bacillus subtilis (3.17%), before the wearing of contact lenses. A statistically insignificant decrease (p > 0.05) was recorded in conjunctival flora at 3, 6, and 9 months after wearing the contact lenses. In addition, we demonstrated the presence of pathogens in the conjunctival flora of contact lens wearers at 9 months, such as Staphylococcus aureus (2.38%) and Streptococcus viridans (0.79%). We believe that these microorganisms may come from the contamination of the contact lenses, lens cases, and maintenance liquids.     

Microbial colonization of soft contact lenses over time.

PURPOSE: To compare the bacterial colonization of soft contact lenses in subjects for successively increasing periods, up to 13 nights of wear. The aim of this study was to determine whether increasing the length of lens wear predisposed subjects to high levels of microbial colonization of lenses. METHODS: Subjects (N = 20) were divided into those with a prior history of adverse events (N = 6), gram-negative bacterial carriers (N = 6), and those with no previous history (N = 8). RESULTS: There were no temporal changes in microbial colonization of lenses. Lenses from all wearers were colonized at least once during the study by gram-positive bacteria at low numbers (<10 cfu/ml). Gram-negative bacteria colonized lenses at least once in 80% of all wearers. Lenses from gram-negative bacterial carriers were more frequently colonized by Staphylococcus aureus and Pseudomonas sp. compared with subjects with no previous history and subjects with a prior history of adverse events, respectively. Lenses from gram-negative bacterial carriers were less frequently colonized by a range of gram-positive bacteria compared with subjects with a prior history of adverse events. CONCLUSIONS: Increasing the length of lens wear up to 13 nights did not result in a predictable increase in bacterial colonization of contact lenses. Gram-positive bacteria were isolated frequently but in low numbers, whereas gram-negative bacteria were present sporadically.     

The conjunctival and contact lens bacterial flora during lens wear

The conjunctival bacterial flora in wearers of hydrophilic, hard and silicone lenses and in a non-lens control group has been studied. Cultures were also taken from the posterior surface of the various contact lenses. Coagulase negative staphylococci were the most commonly occurring microorganisms both on the conjunctiva and on the lenses. Further identification of these bacteria showed Staph. epidermidis to be the predominant species. Compared with control group a significantly increased frequency of negative conjunctival cultures was found among the lens wearers (P = 0.020). The occurrence of coagulase negative staphylococci was reduced, but the difference was not statistically significant (P = 0.08). Gram-negative bacilli were more frequently found during lens wear (P = 0.012), but were mainly species which are traditionally regarded as apathogenic. The possible influence of lens disinfection, duration of lens wear and eye/lid hygiene on the conjunctival bacterial flora is discussed.     

A market survey of contact lens practice in Hong Kong

Purpose : The aim of this survey was to evaluate the use of contact lenses, current prescribing habits of practitioners and the development of the contact lens market in Hong Kong. Methods : Questionnaires were sent to all registered contact lens practitioners in Hong Kong. This questionnaire sought information about their choices on prescribing contact lenses and lens care products and their opinions on continuing education and future trends of contact lens development. Results : A total of 286 responses (22 per cent) were returned. On average, the respondents reported that 36 per cent of their patients were contact lens wearers and most were myopes. The ratio of new fittings to refittings was 1:3. Of the contact lens wearers, 66 per cent were fitted with planned replacement lenses, mostly daily disposable lenses. Multipurpose solution was the most popular lens care regimen prescribed. Only 48 per cent of astigmatic patients were fitted with toric lenses and the use of overnight orthokeratology and silicone hydrogel lenses was limited. Single vision contact lenses with over‐spectacles and monovision contact lenses were the most popular management for presbyopes. Dryness was the major problem reported by contact lens wearers. Practitioners look forward to further development of custom‐made toric, multifocal and silicone hydrogel lenses. The major source of new contact lens information was communication with contact lens suppliers. Conclusion : Compared to previous reports, there was no significant change in the prescribing habits of practitioners. The major complaint of contact lens wearers is still ocular dryness. The contact lens market is driven by younger contact lens wearers, and planned replacement soft contact lenses together with multipurpose solutions dominate. The use of bifocal/multifocal lenses remained low and practitioners want low cost bifocal/multifocal contact lenses with better visual performance and toric lenses with a wider range in parameters. The use of overnight wear lenses such as silicone hydrogel and ortho‐k lenses is limited and 30 days continuous wear silicone hydrogel lenses are prescribed mainly for daily wear.     

The frequency of ocular symptoms during spectacle and daily soft and rigid contact lens wear.

PURPOSE: Ocular discomfort is the primary reason for discontinuation of contact lens wear. The purpose of the study was to quantify and compare the frequency of ocular symptoms experienced by spectacle wearers and wearers of soft and rigid daily contact lenses. METHODS: We analyzed the results of an ocular symptom survey of prospective volunteers for contact lens clinical trials during the period 1989 to 1995. Questions pertaining to lens-wear experience and ocular symptoms were answered by 883 untrained individuals without active ocular disease. The sample included 664 spectacle wearers, 171 soft contact lens (SCL) wearers, and 48 rigid gas-permeable (RGP) lens wearers. The frequencies of 10 ocular symptoms were compared for each group. Spearman's Rank Correlation was used to test for correlations between symptoms. The chi2 test was used to determine differences between subject groups, adjusted for multiple comparisons. RESULTS: There were no significant differences in the frequency of ocular symptoms between the soft contact lens (SCL) and RGP wearers. The most common symptom was ocular tiredness (27%). None of the symptoms were highly correlated, indicating that they are somewhat different "sensations." Despite ocular discomfort being the primary reason for discontinuation of lens wear, contact lens wearers experienced the same type and severity of symptoms as spectacle wearers. Thus (in order of frequency of occurrence), tiredness, itchiness, watering, pain, aching, excessive blinking, and burning had similar rates of occurrence for all three groups. The two major distinguishing symptoms were dryness and redness, which were reported far more frequently and with greater severity in both contact lens groups (p < 0.001). Grittiness was also reported more with RGP wearers than with spectacle wearers (p < 0.001). CONCLUSIONS: Contact lenses disturb the ocular environment, as evidenced by responses of increased ocular dryness, redness, and grittiness. Despite fundamental differences in SCL's and RGP contact lenses, both groups of contact lens wearers surveyed experienced a similar type and frequency of ocular symptoms.     

Rules and regulations concerning contact lens-related infection

Contact lens-related infectious keratitis is a potentially sight-threatening complication. Bacterial keratitis, mostly due to Gram-negative bacteria, is associated with poor lens hygiene, overnight wear, and contaminated lens care solutions. Contamination of the lens storage case may cause fungal keratitis. Acanthamoeba infection is related to the use of tap water or swimming while wearing soft lenses. Viruses are of less concern among contact lens wearers. Possible transmission of Creutzfeldt-Jakob disease by multi-patient trial lenses must be taken in account. To minimize these risk factors, regulations are applied at various levels: CE marking of contact lenses and care products as they are medical devices; contact lens fitting only by health care professionals; distribution of contact lenses by opticians and lens care solutions by opticians and pharmacists; hygienic management of trial lenses following official recommendations. Contact lens-related keratitis must be reported to health care Authorities.     

In vivo confocal microscopy: increased conjunctival or episcleral leukocyte adhesion in patients who wear contact lenses with lower oxygen permeability (Dk) values

PURPOSE: Contact lens wear is known to threaten the health of the ocular surface. In vivo confocal microscopy (IVCM) to visualize leukocyte rolling and extravasation in inflammation was recently described. We tested the hypothesis that contact lens wear is associated with measurable inflammation in superficial vessels. METHODS: Leukocyte rolling and sticking (hallmarks of the inflammatory process) were recorded by IVCM. IVCM was performed on conjunctival or episcleral blood vessels bilaterally on 55 contact lens wearers (15 male, 40 female) and 22 non-contact lens wearers (8 male, 14 female). Data were analyzed in 2 ways. Considering each vessel as an independent variable resulted in 132 analyzable vessel segments (13 daily disposable contact lenses, 67 traditional contact lenses, 14 rigid gas-permeable lenses, and 38 controls). Considering each subject as an independent variable resulted in analyzable data for 47 subjects (5 daily disposable contact lens wearers, 22 traditional contact lens wearers, 5 rigid contact lens wearers, and 15 control patients). Free-flowing, sticking, and rolling cells were counted in the vessels. Multiple parameters including mean flow velocity, shear rate, rolling cells/mm/min, and sticking cells/mm were calculated. RESULTS: We found no significant difference in leukocyte adhesion between control patients and patients wearing daily disposable, traditional disposable, or rigid gas-permeable lenses in both types of statistical analyses. However, the data regarding vessel segments as an independent variable show that there were more rolling cells in patients who wore contact lenses with oxygen permeability values (Dk) less than 10 as compared to those who wore contact lenses with oxygen permeability values greater than 16 (P < 0.01) or compared to controls (P < 0.01). CONCLUSION: IVCM is a novel, powerful technique to recognize a critical but subclinical component of inflammation. Although our data indicate that contact lens wear does not markedly increase rolling and sticking of leukocytes in conjunctival or episcleral vessels, there may be subclinical inflammation in association with lenses with the lowest oxygen permeability.     

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.