Disposable contact lenses in penetrating keratoplasty.

PURPOSE: To evaluate the therapeutic efficacy of disposable contact lenses in management of complications after keratoplasty. METHODS: Twenty-eight patients with various post keratoplasty complications were fit with disposable contact lenses (45% Vifilcon A and 55% water content). Indications for lens use included persistent epithelial defects, wound leak, graft edema, dry eye and protection of normal corneal epithelium. RESULTS: Success was obtained with the therapeutic use of disposable lenses in 20 of the 28 cases. The best results were seen in maintenance and restoration of healthy ocular surface and small wound leaks. Stromal graft edema with no epithelial involvement was the major area of therapeutic failure. CONCLUSIONS: Disposable contact lenses are an attractive low cost option in the management of complications after keratoplasty. They are particularly useful in maintaining a healthy ocular surface, providing symptomatic relief and avoiding resurgery in patients with small wound leaks.     

Ultraviolet transmittance of monthly replacement lenses on the Scandinavian market

Ultraviolet (UV) radiation is reported to be harmful to the human retina even at relatively low levels of daily exposure. Advertising for UV-blocking contact lenses in the media suggests that these materials offer good protection of the eye from UV radiation. The protective effect of such lenses will be dependent on the absorption characteristics and the stability of the UV filter incorporated in the contact lens matrix. The transmittance characteristics of a selection of UV-protecting lenses on the market were evaluated by spectrophotometry. It was demonstrated that the transmittance characteristics were strongly dependent on the lens material. An increase in UV transmittance was observed for some of the lens materials after exposure to light corresponding to approximately 1 hour of sunlight per day through the period of use. None of the lenses offer complete protection from exposure to UV radiation.     

Ultraviolet absorption by contact lenses and the significance on the ocular anterior segment

It is well established that both acute and chronic ultraviolet (UV) exposure can lead to various ophthalmic pathologic conditions in the anterior segment. Several scientific studies have demonstrated that after UV exposure, the unprotected cornea is vulnerable to damage in the epithelial, stromal, and endothelial cellular layers. DNA damage, apoptosis, and altered protease expression are all examples of harmful changes that can occur within the cornea after irradiation. Beyond the cornea, damage associated with UV exposure, such as decreased antioxidant levels and increased reactive oxygen species production, has been noted in the aqueous humor and crystalline lens. Ultraviolet-blocking contact lenses have the potential to provide protection against such exposure to harmful UV radiation. Experimental use of UV-absorbing contact lenses prevented detrimental cellular changes to the cornea and maintained corneal clarity after UV exposure. Additionally, studies suggest that shielding the aqueous humor and crystalline lens from irradiation with UV-absorbing contact lenses aids in protection against precataractous changes. Despite ongoing research, to date, neither chronic nor clinical studies have been performed in humans to demonstrate that wearing UV-blocking contact lenses reduces the risk of developing cataracts or other ocular disorders within the anterior segment. This article will discuss the impact of UV exposure on ocular tissue and the need for adequate UV protection, with particular emphasis on UV-blocking contact lenses.     

Ultraviolet-absorbing spectacle lenses, contact lenses, and intraocular lenses

Optical materials that are available to the practitioner for protection of the eye against hazardous exposure to ultraviolet radiation (UVR) are discussed. Principles of protection, procedures for calculating safe ocular exposure duration, and transmittance curves of commonly prescribed spectacle lenses, contact lenses, and intraocular lenses are discussed. Suggestions are made to assist the practitioner in providing adequate protection for the patient.     

Glassblowers' ocular health and safety: optical radiation hazards and eye protection assessment

The arms of this study were to investigate the levels of optical radiation exposure in glassblowing and to determine type(s) of protective eyewear commonly used. Radiometric measurements of radiant emissions from different molten glass materials and heating systems were carried out in six installations. Spectral transmittance curves of available protective lenses used at the locations were obtained. Significant variation ( P = 0.0001) in ocular irradiation was obtained. All operations produced irradiances higher than the threshold limit values (TLVs for the visible spectrum (400 to 700 nm). In craft glassblowing which employs furnace systems, irradiance levels exceeding the TLVs for near infrared (760 to 1100nm) were obtained. Molten soda-lime and quartz glasses emitted substantial subthreshold near UV radiation. This study shows that variation exists in glassblowing ocular radiation exposure due to different glass materials and heating systems, therefore selection of appropriate eye protector should be on an individual basis.     

Is it necessary to enzyme-clean programmed-replacement soft contact lenses for daily wear?

Twelve subjects were fitted with Bausch & Lomb Medalist programmed-replacement contact lenses. The lenses were worn on a daily wear basis for a period of 3 months, during which subjects cleaned their lenses each night, rinsing and storing them in a disinfecting solution. One of each subject's lenses was enzyme-cleaned weekly by an optometric technician. Neither the subjects nor the clinicians knew which lens (right or left) was being enzyme-cleaned. At biweekly follow-up visits, subjects were questioned concerning lens comfort, ocular health was evaluated, and the lenses were inspected for the presence of deposits. Differences between enzyme-cleaned and non-enzyme-cleaned lenses were absent or minimal for lens awareness, ocular health, and the severity and extent of deposits. It was concluded that when Bausch & Lomb Medalist lenses are worn for a period of 3 months and are cleaned daily the use of an enzyme cleaner is not necessary for patient comfort and physiological tolerance to the lenses.     

Meibomian gland dysfunction and ocular discomfort in video display terminal workers

PURPOSE: Meibomian gland dysfunction (MGD) is one of the most common ocular disorders encountered in clinical practice. The clinical manifestations of MGD are related to the changes in the tear film and ocular surface with symptoms of ocular discomfort. In recent years, many surveys have evaluated symptoms associated with the use of Video Display Terminals (VDT), and VDT use is recognized as a risk factor for eye discomfort.The aim of the present study was to determine if the presence of MGD contributes to the signs and symptoms of ocular discomfort during the use of VDT. METHODS: In course of a routine health surveillance programme, a group of 70 subjects fulfilled the inclusion criteria and responded to a questionnaire about symptoms of ocular discomfort. The following ocular tests were performed: tear break-up time, fluorescein corneal stain, and basal tear secretion test. RESULTS: A total of 52 subjects out of 70 (74.3%) had MGD. A statistically significant correlation between the symptoms of ocular discomfort and hours spent on VDT work was observed in the total population (r=0.358; P=0.002; 95% CI 0.13-0.54) and in the group of subjects with MGD (r=0.365; P=0.009; 95% CI 0.103-0.58). Such correlation was not shown in subjects without MGD. CONCLUSIONS: The high prevalence of MGD among the subjects with symptoms of ocular discomfort suggests that this diagnosis should be considered when occupational health practitioners encounter ocular complaints among VDT operators. It appears that MGD can contribute to the development of ocular discomfort in VDT operators.     

Ocular manifestations in bidi industry workers: possible consequences of occupational exposure to tobacco dust

Tobacco consumption is the leading preventable cause of disease, disability, and premature death but little is known about its deleterious effect on the ocular health of workers handling tobacco. The goal of this study was to identify probable effects of occupational tobacco exposure among south Indian bidi-industry workers. This study included 310 females (mean age, 34.8 +/- 10.9 years) actively involved in bidi-rolling presenting with eye symptoms to a tertiary eye care hospital. Results suggested that a wide spectrum of ocular complications exist among these workers. Common ocular symptoms were defective vision, dull-aching headache and eye irritation. The main ocular findings were papillary conjunctival hyperplasia, hyperpigmentation of ocular surface, punctate epithelial erosion or superficial punctate keratitis, cataract or pseudophakia and segmental optic atrophy. Abstaining from work, supplementation of Vitamin B complex rich in B 12 and appropriate surgical or medical management reversed visual loss due to corneal disease or cataract but was not effective in optic neuropathy.     

The vision of welders in France

PURPOSE: A study was conducted to measure the impact of welding on the vision of welders. Methodology:This study was conducted in France by the occupational medicine staff of large companies on 1.131 people, namely 850 welders and 281 control subjects. This investigation included two examinations at the beginning and the end of a year. The investigative procedure examined the different welding processes, the percentage of working time spent on welding activity, the length of exposure in years, as well as the medical variables: the optical correction type and history of ocular traumatology. The Visiotest or the Ergovision were used for the visual examination, equipment in common use by occupational medicine departments. RESULTS: The welders were comparatively young (59.53% of them were less than 45 years old). Moreover, for 69.75% of the welders, more than 75% of their activity was devoted to welding. All currently used welding processes were represented, including the modern PLASMA-TIG welding process. No excessive blood alcohol levels were observed in all subjects, but welders did smoke slightly more than the control subjects (40% vs 33%). Self-medication was rather less frequent among the welders, except as regards the use of eye drops, where the proportions were clearly inverted. Optical correction for hyperopia was similar between the two groups; however, as regards myopia, the welders were corrected less often. Lastly, contact lens use was exceptional among the welders. Nearsightedness varied logically with age, but also, inexplicably, with the welding processes. Vision recovery time after exposure to glare was much longer among the welders, except for the PLASMA-TIG processes. No difference was observed in the other parameters of the study. No change in the visual functions studied was noted between the two examinations. DISCUSSION: The examination techniques used showed no impairment of the studied visual functions, probably because companies use protective and preventive eye care methods. Moreover this study is the first to examine the type of welding used by workers and particularly the modern PLASMA-TIG process. The vision recovery time after exposure to glare seems better for the PLASMA-TIG process may be the result of the lower luminous intensity of this process. CONCLUSION: This study was conducted for preventive purposes to contribute to better monitoring of safety and comfort for welding workers and has shown no alteration of the visual function among welders in general.     

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.     

An impression cytology based study of ocular surface in an urban population

To assess the health of ocular surface in a defined urban population, conjunctival goblet cell density and degree of surface squamous metaplasia were utilized as study tools. Two thousand names of those aged between 20 and 79 years from the 2006 electoral register in ward number 63 of Kolkata Corporation area were initially selected. Normal healthy human volunteers without any history of ocular surface disorder were recruited and divided into five age-groups. Impression cytology samples were obtained from interpalpebral part of bulbar conjunctiva from all the participants fixated and stained by a single observer. A stratified, clustered, disproportionate, random sampling method was used. The software used in the statistical analysis was EPI Info. The tests applied were t test and ANOVA. A variation in the number of goblet cells according to gender (women having less cells) and age (20–30 years group having the highest number of cells) was found. Those working outdoors were found to have fewer goblet cells compared to those who stay indoors. The majority of the people had grade 1 cytological appearance in both males and females. There was no statistically significant difference in Nelson’s grading with age. People using coal and kerosene to cook were found to have a smaller goblet cell density than those who cooked on LPG or those who did not cook at all. Besides age and sex, environmental factors like the method of cooking and occupational variables (like outdoor activity, prolonged period of computer use, etc.) modify the health of the ocular surface. The results of this study will help put these findings into perspective as public health problems.     

大学生视屏终端暴露时间与视屏终端相关眼病相关性分析

目的:探讨大学生视屏终端(visual display terminal,VDT)暴露时间与视屏终端相关眼病的相关性。方法:对珠海市3所高校1218名在校本科生进行问卷调查,了解视屏终端暴露时间、眼部症状评分,对不同年级学生视屏终端暴露时间及不同暴露强度人群眼部症状评分进行比较,并对视屏终端暴露时间与眼部症状评分进行相关性分析。结果:3所高校本科生视屏终端暴露时间平均为3.72±2.17h,随着年级的增长,视屏终端暴露时间延长,暴露时间越长,眼部症状越明显,视屏终端相关眼病与视屏终端暴露时间具有正相关性。结论:长时间视屏终端暴露不利于眼健康。应加强对大学生的眼保健教育,避免或减少视屏终端暴露带来的健康损失。     

The evidence of SARS-CoV-2 infection on ocular surface

This is a cross-sectional study of patients who received a COVID-19 diagnosis between December 30, 2019 and February 7, 2020 at Tongji Hospital. A total of 102 patients (48 Male [47%] and 54 Female [53%]) with clinical symptoms, Rt, and chest Computed Tomography (CT) abnormalities were identified with a clinical diagnosis of COVID-19. Patients had a mean [SD] gestational age of 57.63 [14.90] years. Of a total of 102 patients identified, 72 patients (36 men [50%] and 36 women [50%]; mean [SD] age, 58.68 [14.81] years) were confirmed to have COVID-19 by laboratory diagnosis with a SARS-CoV-2 RT-PCR assay. Only two patients (2.78%) with conjunctivitis were identified from 72 patients with a laboratory confirmed COVID-19. Of those two patients, SARS-CoV-2 RNA fragments were found in ocular discharges by SARS-CoV-2 RT-PCR in only one patient. Our findings suspect the incidence of SARS-CoV-2 infection through the ocular surface is extremely low, while the nosocomial infection of SARS-CoV-2 through the eyes after occupational exposure is a potential route. To lower the SARS-CoV-2 nosocomial infection, all health care professionals should wear protective goggles. The inefficient diagnostic method and the sampling time lag may contribute to the lower positive rate of conjunctival swab samples of SARS-CoV-2.     

Overwear of contact lenses: increased severity of clinical signs as a function of protein adsorption.

This study compared the clinical behavior of disposable and frequent replacement Acuvue and 1-Day contact lenses. Each type of lens was worn on one eye according to the schedule recommended by the manufacturer, and on the other eye for a longer period of time, up to 30 days in length. Both type of lenses were prescribed on a daily-wear basis. The amount of protein collected from the lenses was measured using two spectrophotometric protein assays. Visual acuity and comfort, along with several other clinical signs, were classified according to Cornea and Contact Lens Research Unit (CCLRU) scales, and possible associations between each of these signs and the amount of protein extracted from the lenses was tested. A comparison between the lens worn on the compliant eye with the lens worn on the noncompliant eye allowed us to measure the impact of overwear on ocular health and subjective clinical findings. After four months of study, the overwear of Acuvue and 1-Day lenses significantly increased the amount of protein bound on the contact lenses, as well as the severity of upper conjunctival papillae, upper lid conjunctival hyperemia, and limbal congestion. Even if reduced values for visual acuity and noninvasive break-up time (NIBUT) were identified, these variations were not found to be statistically significant. The clinical implications of this study would allow a practitioner to identify, according to the variations in several clinical signs, a patient who overwears contact lenses, so that action may be taken to reduce possible deleterious effects on ocular health.     

Sun exposure and pterygium of the eye: a dose-response curve.

PURPOSE: To present a quantitative analysis of pterygium and ocular sun exposure, a dose-response curve, and a discussion of the health-promotion implications of the findings. METHODS: A hospital-based, case-control study was conducted in Perth, Western Australia. Case subjects had surgical removal of a pterygium; control subjects had an ear, nose, or throat procedure. A lifetime history of residence, sun exposure patterns, and use of hats, spectacles, and sunglasses was obtained at interview. Measures of potential sun exposure included latitude, daily sunshine hours, and daily global solar radiant energy. The most complex estimate of actual sun exposure was the daily ocular solar radiation dose, calculated from climatic data, time spent outdoors not under shade, and the use of hats and spectacles. RESULTS: There were strong positive associations between pterygium and measures of potential and actual sun exposure. Associations were as strong for whole-life measures as for those in any specific age range. Pterygium odds ratios increased with exposure level; the odds ratio was 4.0 (95% confidence interval, 1.6 to 10.9) for the highest quarter of the daily sun exposure. The strongest associations were seen for the estimated daily ocular solar radiation dose, with an odds ratio of 6.8 (95% confidence interval, 2.6 to 19.7) for the highest quarter of exposure. CONCLUSIONS: Pterygium is strongly related to ocular sun exposure, with little evidence that exposure during any particular period of life is more important than in other periods; the implication for prevention of pterygium is that ocular protection is beneficial at all ages.     

Do tinted spectacle lens wearers have a different personality?

The wearing of tinted spectacle lenses is considered by some health care workers to be a marker of psychopathology or a hypochondriacal personality type. The purpose of this study was to determine whether there is a relationship between the wearing of tinted spectacle lenses and personality type in physically healthy subjects. The Sixteen Personality Factor Questionnaire 5th Edition, a multidimensional standardized self‐report inventory, was used to determine the personality type of 98 participants. Twenty currently wore tinted spectacle lenses for reasons other than ocular disease, sun protection, outdoor or indoor glare reduction, pattern sensitive epilepsy, migraines, reading difficulties or fashion. The remainder did not wear tinted spectacle lenses for any purpose other than sun protection. Tinted lens wear and no tinted lens wear groups were age and gender matched. There was no statistically significant difference in five global personality factors between the no‐tint and tint groups: extraversion (p = 0.31), anxiety (p = 0.75), tough‐mindedness (p = 0.96), independence (p = 0.63), and self‐control (p = 0.87). This suggests that the use of tinted lenses by physically healthy people is unlikely to be an indicator of personality type.     

角膜塑型接触镜配戴的微生物研究

目的了解角膜塑型接触镜配戴者眼部、镜片及护理用品的微生物状况,了解角膜塑型接触镜配戴者眼部感染的可能原因,为临床治疗提供依据.方法从配戴角膜塑型镜者结膜囊、常规清洗消毒前后镜片、镜盒及护理液取材进行细菌、真菌及阿米巴培养,并按常规方法进行鉴定.结果细菌检查阳性率结膜囊为66.3%;清洗消毒前后镜片分别为72.4%和11.2%(P＜0.01);镜盒同清洗消毒前镜片;多功能护理液为8%(4/50).眼部感染者均检出有细菌生长.结论角膜塑型接触镜配戴者镜片及护理用品有微生物污染,常规的护理操作可明显减少镜片上污染的微生物.     

Silicone hydrogel contact lenses and the ocular surface

For 30 years, contact lens research focused on the need for highly oxygen-permeable (Dk) soft lens materials. High Dk silicone hydrogel contact lenses, made available in 1999, met this need. The purpose of this review is to examine how silicone hydrogel lens wear affects the ocular surfaces and to highlight areas in which further research is needed to improve biocompatibility. Silicone hydrogel lenses have eliminated lens-induced hypoxia for the majority of wearers and have a less pronounced effect on corneal homeostasis compared to other lens types; however, mechanical interaction with ocular tissue and the effects on tear film structure and physiology are similar to that found with soft lens wear in general. Although the ocular health benefits of silicone hydrogel lenses have increased the length of time lenses can be worn overnight, the risk of infection is similar to that found with other soft lens types, and overnight wear remains a higher risk factor for infection than daily wear, regardless of lens material. Future contact lens research will focus on gaining a better understanding of the way in which contact lenses interact with the corneal surface, upper eyelid, and the tear film, and the lens-related factors contributing to infection and inflammatory responses.     

Association between Exposure to Smartphones and Ocular Health in Adolescents

Purpose: Smartphone use has dramatically increased in recent years. Smartphones may have adverse health effects, particularly on the eyes, because users stare at the screen for a much longer time than they do with ordinary mobile phones. The objective of this study was to elucidate the relationship between smartphone use and ocular symptoms among adolescents.

Methods: Information on smartphone use and ocular symptoms (blurring, redness, visual disturbance, secretion, inflammation, lacrimation and dryness) related to eye fatigue and strain from 715 adolescent subjects from three cities in Korea was obtained using a structured questionnaire. Ocular health was scored using number of ocular symptoms. Odds ratios (ORs), 95% confidence intervals (95% CIs) and p-values for ocular symptoms were calculated with binomial and multinomial logistic regression models.

Results: Higher prevalence rates for ocular symptoms were observed in groups with greater exposure to smartphones (p < 0.05). Longer daily smartphone use was associated with a higher likelihood of having multiple ocular symptoms (5–7 symptoms out of 7 symptoms; p = 0.005). Excessive/intermittent use (>2 hours daily and ≤2 hours continuously) and excessive/persistent use (>2 hours daily and >2 hours continuously) compared to shorter use (<2 hours daily) were associated with multiple ocular symptoms (OR 2.18, 95% CI 1.09–4.39; OR 2.26, 95% CI 1.11–4.57, respectively). A higher lifetime exposure to smartphones was associated with a higher likelihood of having multiple ocular symptoms (OR 3.05, 95% CI 1.51–6.19; p = 0.001).

Conclusion: Increasing exposure to smartphones can have a negative impact on ocular health in adolescents.