A comparison of spectacle and contact lens wearing times in the ACHIEVE study

Purpose: The aim was to compare vision correction wearing time between myopic children and teenagers in a clinical trial of contact lenses and spectacles. Methods: Parents of subjects in the Adolescent and Child Health Initiative for Vision Empowerment (ACHIEVE) study provided wearing times for spectacle and contact lens wear. Hours wearing primary correction and total correction were compared between the two treatment groups. Other factors hypothesised to be associated with wearing time were analysed. Results: The average wearing time of the primary correction differed significantly with the wearing time for the spectacles group being 91.5 hours per week compared to 80.3 hours per week for the contact lens wearers (p < 0.0001). Total correction time was slightly higher for the contact lens wearers, 97.5 hours per week, after accounting for time wearing spectacles. Higher refractive error was strongly related to longer wearing times (p < 0.0002). Age and treatment group were associated with wearing time (p = 0.005). Young contact lens wearers wore their lenses less than young spectacle wearers and older contact lens wearers. Low scores on an appearance quality‐of‐life scale were associated with longer wearing time in spectacle wearers compared to the low‐ and high‐scoring contact lens wearers. Gender, spectacle satisfaction and activities were not related to wearing time. Conclusions: While contact lens wearers, on average, wear their contact lenses less than spectacle wearers, they spend roughly the same amount of time wearing a refractive correction. Higher refractive error resulted in longer wearing times for both spectacle and contact lens wearers. Younger contact lens wearers wore their contact lenses for shorter periods than the spectacle wearers, but still wore them, on average, 74.4 hours per week (about 10 hours per day), suggesting that contact lenses are a viable alternative mode of correction for children.     

Visual acuity in contact lens wearers.

PURPOSE: The difference between high- and low-contrast visual acuity provides a sensitive indicator of vision loss in ocular disease; however, the effect of refractive error correction on this difference is still debated. METHODS: High- and low-contrast visual acuity was measured in 116 rigid gas permeable contact lens wearers, 51 spectacle wearers, and 50 soft contact lens wearers with habitual and best correction. Twenty-nine of the soft contact lens wearers reported that they wore disposable contact lenses (discarded on a monthly or more frequent basis), whereas the other 21 soft contact lens wearers wore traditional soft contact lenses. RESULTS: Rigid gas permeable contact lens wearers had statistically worse high-contrast habitual visual acuity than spectacle wearers (Tukey-Kramer, p = 0.0075). Traditional soft contact lens wearers had significantly worse low-contrast visual acuity compared with all other groups (Tukey-Kramer, p < 0.02 for each comparison). Traditional soft contact lens wearers had a significantly larger difference between high- and low-contrast visual acuity with best correction compared with rigid gas permeable wearers (Tukey-Kramer, p = 0.0099). CONCLUSIONS: Rigid gas permeable contact lens wearers had statistically worse habitual high-contrast visual acuity compared with spectacle wearers, but no difference was present under best-corrected conditions. We hypothesize that rigid gas permeable contact lens wearers were not wearing their optimal correction habitually. Traditional soft contact lens wearers had significantly worse low-contrast visual acuity. They also had a larger difference between their best-corrected high- and low-contrast visual acuity scores compared with rigid gas permeable contact lens wearers.     

Visual performance of subjects wearing presbyopic contact lenses.

PURPOSE: The purpose of this study is to assess the visual performance of subjects wearing gas-permeable (GP) multifocal contact lenses, soft bifocal contact lenses, GP monovision lenses and spectacles. METHODS: The study included 32 subjects between the ages of 42 and 65 years wearing GP monovision, the Acuvue Bifocal (Vistakon), the Essentials GP Multifocal (Blanchard), and progressive addition lenses (PAL; spectacles group). There were eight subjects in each of these groups who were already wearing these modalities. Binocular low (18%) and high (95%) contrast acuities were recorded using the Bailey-Lovie chart; binocular contrast sensitivity from 1.5 to 18 cycles per degree (cpd) measured with the Vistech VCTS 6500 system, and monocular glare sensitivity at three luminance settings (400, 100, and 12 foot lamberts) was measured using the brightness acuity tester (BAT). Binocular near visual task performance (a modified version of letter counting method used in previous presbyopic studies) was also assessed. RESULTS: For the contact lens-wearing groups, subjects wearing GP multifocals provided the best binocular high and low contrast acuity followed by soft bifocal wearers. There was relative parity between the binocular high and low contrast acuity with PAL and GP multifocal wearers. Monovision acuity, measured binocularly, was determined to be lower than the other three groups with this difference being most significant with high contrast acuity. Among contact lens-wearing groups, it was observed that GP multifocal lens wearers experienced the lowest amount of monocular disability glare followed by soft bifocal wearers and monovision wearers. Subjects wearing soft bifocal lenses and monovision demonstrated slightly reduced binocular contrast sensitivity at all spatial frequencies. In the contact lens groups, GP multifocal lens wearers had the highest binocular contrast sensitivity at all spatial frequencies, on parity with PAL wearers, except at the highest spatial frequency (18 cpd) at which PAL wearers had better vision. Error scores for the binocular near visual task performance between the four groups revealed subjects with GP multifocal lenses and PAL wearers to have the least errors, followed by monovision users and then soft bifocal wearers with the most errors. CONCLUSION: Subjects wearing GP multifocals, soft bifocals, monovision, and PAL spectacles have good binocular contrast sensitivity, satisfactory binocular low and high contrast acuity, and increased sensitivity to glare. Presbyopic subjects requiring the use of contact lenses under dim light levels could benefit from GP multifocal lenses. Contrast and glare sensitivity evaluations provide significant information regarding the visual performance of the presbyopic contact lenses and should be included in regular presbyopic contact lens fitting.     

Glare and halo with refractive correction

Background: The aim of this investigation was to compare glare and halo with various methods of refractive correction. Methods: Ninety‐eight eyes of healthy pre‐presbyopes were analysed for the presence of glare and halo using computer‐generated stimuli. Subjects were divided into three groups: emmetropes without correction, single vision plastic lens spectacle wearers (with clean and dirty lenses) or single‐vision soft contact lens wearers. Results: No significant difference in glare was found among groups. Significant differences were noted in halos between emmetropes and both contact lens (p < 0.001) and uncleaned spectacle groups (p < 0.05) but not with cleaned spectacles. The reduction in halo size after cleaning the lenses was significant (p < 0.0187). Conclusions: Contact lens and unclean spectacle wearers both have significantly larger halos than emmetropes and those wearing cleaned spectacle lenses. Unclean spectacles may affect the accuracy of results in psychophysical and clinical testing.     

Myopia progression in adolescent wearers of soft contact lenses and spectacles.

The purpose of this 3-year, randomized clinical trial was to determine the difference in myopia progression in adolescents wearing soft contact lenses over a control group wearing spectacles. A total of 175 adolescents between the ages of 11 and 14 years were randomized into 2 groups, spectacle wearers and soft contact lens wearers. The main result was that the spherical equivalent change between the groups showed no clinical or statistically significant difference. However, when a power vector analysis was used, which uses all the refractive error data, a small but statistically significant (F test = 4.24, T2 = 17.35, p < 0.01) difference between the groups was found (i.e., the refractive error of the spectacle wearers had a slight increase in astigmatism). It can be concluded that soft contact lens wear does not lead to additional myopia progression in adolescents.     

Vision-specific quality of life and modes of refractive error correction.

PURPOSE: Many studies currently use surveys to assess patients' reports of vision-specific quality of life to determine the impact of the disease or the most appropriate mode of treatment. One such instrument, the National Eye Institute Visual Function Questionnaire (NEI-VFQ), was developed to assess vision-related quality of life with respect to emotional well-being and social function as well as difficulty with tasks and symptoms. We administered the NEI-VFQ to 218 subjects free of eye disease to see if the survey was sensitive enough to detect differences in three modes of refractive error correction: spectacles, soft contact lenses, and rigid contact lenses. METHODS: Surveys were administered to 117 rigid contact lens wearers, 51 spectacle wearers, and 50 soft contact lens wearers. Kruskal-Wallis one-way analysis of variance was conducted to determine significant differences in each of the subscales. RESULTS: The Peripheral Vision subscale score (mean +/- SD) was 92.6 +/- 15.2 for the spectacle wearers, 100.0 +/- 0.0 for the soft contact lens wearers, and 98.3 +/- 7.1 for the rigid gas-permeable contact lens wearers; the spectacle wearers' Peripheral Vision score was significantly lower than the other two groups (Wilcoxon rank sum, p < 0.003 for both). The spectacle wearers (96.6 +/- 9.2) also had a significantly lower Dependency subscale score than the rigid contact lens group (99.7 +/- 1.5) (Wilcoxon rank sum, p = 0.001). There were no significant differences between the three groups detected in the mean of any of the other subscale scores. At least 50% of the subjects reported the maximum score for 6 of the 11 subscales. Given our sample size, we have 100% power to detect a difference of 10 points with a SD of 10 at the alpha = 0.05 level. CONCLUSION: The NEI-VFQ is not appropriate for detecting significant differences in vision-related quality of life among spectacle, soft contact lens, and rigid gas-permeable contact lens wearers, primarily due to maximum ratings by many of the subjects.     

不同矫正方式对近视患者双眼视功能的影响

目前常用的近视矫正方式有框架眼镜、角膜接触镜以及屈光手术三种.框架眼镜安全廉价,可作为中低度近视且无屈光参差患者的首选,而高度近视或屈光参差近视患者配戴角膜接触镜(包括角膜塑形镜、硬性透气性角膜接触镜、软性角膜接触镜等)更易获得良好的双眼视功能.在减少屈光参差对近视者双眼视功能损害方面,屈光手术也能获得良好的效果.     

Comparison of multifocal and monovision soft contact lens corrections in patients with low-astigmatic presbyopia.

PURPOSE: The purpose of this study was to assess visual performance and patient satisfaction with two presbyopic soft contact lens modalities. METHODS: A crossover study of 38 patients with presbyopia was conducted. Patients were randomized first into either multifocal (Bausch & Lomb SofLens Multifocal) or monovision (SofLens 59) for 1 month. Visual performance was measured with high- and low-contrast visual acuity at distance and near and near stereoacuity. Patients' satisfaction was measured by the National Eye Institute Refractive Error Quality of Life Instrument questionnaire and by recording the patient's final lens preference. RESULTS: Patients maintained at least 20/20 binocular vision with both multifocal (MF) and monovision (MV) contact lenses under high-contrast conditions at distance and near. Under low-contrast conditions, patients lost less than a line of vision from the best spectacle correction to either multifocal or monovision contact lens correction at distance (pMF = 0.001, pMV = 0.006). Under low-contrast conditions at near, multifocal wearers lost five to six letters and monovision wearers lost two letters of vision (pMF < 0.001, pMV = 0.03, pMF/MV = 0.005). The average stereoacuity decreased by 79 s arc with monovision vs. multifocal contact lenses (p = 0.002). On the NEI-RQL, patients reported worse clarity of vision (pMF = 0.01, pMV < 0.001), more symptoms (pMF = 0.09, pMV = 0.01), and an improvement in their appearance with contact lens wear (pMF < 0.001, pMV < 0.001). Seventy-six percent of patients reported that they preferred multifocal contact lenses, and 24% preferred monovision contact lenses (p = 0.001). CONCLUSION: The majority of our patients preferred multifocals to monovision, most likely because the Bausch & Lomb SofLens Multifocal provides excellent visual acuity without compromising stereoacuity to the same degree as monovision.     

Interest of presbyopes in contact lens correction and their success with monovision.

The presbyopic population is seen as a large potential source of contact lens wearers. The aims of this study were: (1) to estimate the percentage of presbyopes interested in contact lenses, (2) to ascertain the success of interested presbyopes with monovision correction, and (3) to determine the percentage willing to continue wearing monovision lenses after 1 month's trial. Seven practitioners in Sydney surveyed consecutive presbyopes attending their practices about their interest in contact lenses. Of the 1133 presbyopes surveyed, 314 (28%) were interested in trying monovision lenses. A total of 72 patients were subsequently fitted with monovision in high water content hydrogel form. After 1 month, 46 of these patients (64%) were still wearing the lenses, and 39 (54%) expressed willingness to continue with monovision correction. The major reasons for discontinuation from lens wear during the 1-month trial were inadequate vision and difficulty in lens handling.     

Contact lenses in the military service

This paper discusses contact lenses in a military environment and reports the results of a literature survey, an extensive questionnaire sent to 1400 spectacle and contact lens wearers, and a short questionnaire given to soldiers taking part in a large scale and long military maneuver. Only a small number of publications were found concerning the relation between adverse environmental conditions and contact lens wearing. In Vietnam dust and poor hygiene often led to eye irritations that precluded the wearing of contact lenses by soldiers. Nevertheless, persons in the army are often in favor of contact lenses. In the air force and navy, wearing contact lenses seems compatible with nearly all military duties. A questionnaire was sent to all known contact lens wearers in the Dutch army and air force and to about an equal number of spectacle wearers. The responses indicate that the proportion of contact lens wearers is 1.8%. The distribution of hard vs. soft lenses was 60 and 40%, respectively. Military personnel wore their lenses during nearly all daily activities. Most contact lens wearers were of the opinion that in military conditions contact lenses have advantages over spectacles. To obtain more information on field exercises, a second questionnaire was handed out immediately after a large-scale NATO field maneuver. Twenty percent of the contact lens wearers had decided in advance not to wear their lenses, but another 30% ceased wearing their lenses during the exercise. It was recommended that for nearly all functions and/or conditions, wearing of contact lenses should be allowed, but that during extended field exercises wearing of hard contact lenses should be discouraged.     

The Quest for Spectacle Independence: A Comparison of Multifocal Intraocular Lens Implants and Pseudophakic Monovision for Patients with Presbyopia

ABSTRACT

We performed a literature review comparing multifocal intraocular lens (IOL) implantation with pseudophakic monovision to treat presbyopia. Multifocal IOLs utilize refractive or diffractive principles to treat both distance and near vision, with a single lens implant. Monovision uses traditional monofocal lens implants to treat the dominant eye for emmotropia, and the non-dominant eye for myopia. This planned anisometropia is designed to enhance intermediate or near vision. Generally, distance vision was similar with both types of lens implantation, near vision was better with multifocal IOLs, and intermediate vision appeared to be better in the monovision group. For patients requiring cataract surgery, both multifocal IOLs and monovision appear to address presbyopia with a high level of patient satisfaction. More patients reported complete spectacle independence with multifocal IOLs, but more glare and halos were reported by multifocal IOL patients as well.     

少年儿童眼外伤术后无晶体眼的接触镜矫正

目的探讨少年儿童单眼外伤术后无晶状体眼的接触镜(CL)矫正方法和临床效果.方法观察81名少年儿童眼外伤术后患者的眼部改变,并根据其屈光状态的变化、对侧眼的状态及其生活的实际需要,选择验配了软性接触镜(SCL)、托力克软性接触镜(TSCL)、透气性硬性接触镜(RGPCL)、加虹膜色彩的非透气性硬性接触镜(PMMA虹彩片)和软、硬组合型镜片系统(Piggyback CL),并比较视力矫正效果.结果与对侧健眼比较,外伤术后眼角膜曲率半径值显著改变,角膜散光度明显增加.52眼选用SCL和TSCL,矫正视力与框架眼镜比较无明显差异;22眼选用RGPCL,4眼选用PMMA虹彩镜,3眼选用Piggyback CL,三种镜片矫正视力比框架眼镜明显提高.PMMA虹彩镜和Piggyback CL用于外伤后角膜白斑、术后无晶状体、虹膜严重损伤眼,除显著提高视力外,还明显改善了羞明症状和眼外观.结论在严格的医疗化管理下,利用CL矫正少儿眼外伤术后无晶状体眼的高度屈光不正、屈光参差,恢复双眼视觉是安全、有效的.硬性接触镜(HCL)的视力矫正效果明显优于SCL.     

Patterns of binocular suppression and accommodation in monovision

The binocular depth of focus of monovision wearers was compared to the sum of the two monocularly determined depths of focus. Observers fell into three groups based upon ocular sighting dominance. Complete binocular summation of the monocular depths of focus was observed in subjects without a preferred fixating eye. Subjects who preferred to fixate with one eye had difficulty suppressing blur of that eye while the binocular target was within the depth of focus of the nonpreferred eye. A third group showed partial summation of the two monocular depths of focus. Similar patterns of accommodative response, measured objectively with the SRI optometer, were observed in subjects wearing monovision corrections. Accommodative response to sinusoidal variations in blur was controlled primarily by the dominant sighting eye. These results demonstrate the effectiveness of interocular suppression of anisometropic blur in monovision correction and the influence of ocular dominance upon this suppression process.     

Ocular dominance and the interocular suppression of blur in monovision

Presbyopic contact lens patients with monocular corrections (monovision) see clearly at all distances by virtue of an interocular suppression of anisometropic blur that occurs regionally between corresponding retinal areas. This suppression fails to occur with small high-contrast targets viewed under low luminance conditions. The effect of target size and contrast upon interocular suppression of blur was quantified by reducing contrast of a bright test spot, viewed binocularly while wearing various plus lenses monocularly, until the out-of-focus image was suppressed. The strength of interocular suppression was equivalent when the plus lens was before either eye. However, after subjects wore a plus lens over their nonsighting eye for one day, interocular suppression of blur became enhanced when the nonsighting eye was blurred, and it became reduced when the sighting eye was blurred. Successful monovision subjects suppressed blur at higher contrast levels than did unsuccessful subjects. These results suggest a possible clinical test for quantifying adaptation to monovision.     

The cornea swells in the posterior direction under hydrogel contact lenses

Two mathematical models were developed to describe the topographical corneal swelling response to hydrogel contact lenses and the effect of these changes on refractive error. In one, corneal thickness changes resulted in deformation of the anterior corneal surface. In the other, the posterior surface only was deformed. Refractive error, corneal thickness and corneal shape were monitored in a sample of adapted contact lens wearers with one eye patched for 4 h while wearing a soft contact lens. The experimental data were most consistent with the model in which the posterior surface only was deformed.     

框架镜与接触镜配戴者在近视激光手术前后的生活质量比较

目的:研究配戴框架镜与配戴角膜接触镜的近视患者接受准分子激光手术后生活质量的变化。方法:选取72例接受准分子激光近视手术的患者按术前矫正方式不同分为两组,配戴框架镜组50例,配戴角膜接触镜组22例,应用2007年中文版屈光矫正者生活质量量表(the quality of life impact of refractive correction,QIRC)在术前和术后3mo进行问卷调查。结果:(1)准分子激光近视手术后配戴框架镜组的生活质量(术后42.29±4.90,术前39.30±5.16)和满意度评分(术后86.51±9.14,术前71.58±13.24)均高于术前,差异均有统计学意义(P<0.01)。增加显著的模块是视功能与身体机能(P<0.01);增加显著的条目包括夜间驾驶(P<0.01)、夜间户外活动(P<0.05)、强光下不戴太阳镜生活或工作(P<0.05)、游泳(P<0.01)、担心花费(P<0.01)、自我感觉(P<0.05)及自信(P<0.01)方面。晨起视物(P<0.05)方面评分则较术前显著减少。(2)准分子激光近视手术后配戴接触镜组的生活质量(术后42.32±5.95,术前41.26±5.21)评分与术前比较无显著差异(P>0.05),但满意度评分(术后87.14±10.64,术前73.77±21.26)较术前显著增加(P<0.01)。在社会活动模块(P<0.05)及游泳(P<0.01)、担心并发症(P<0.05)方面的评分显著高于术前。结论:配戴框架镜的近视患者在接受准分子激光术后生活质量和对矫正方式的满意度明显提高,在视功能、身体机能、运动等方面提高显著。配戴接触镜的近视患者在接受准分子激光术后生活质量与术前相比没有明显差别,但对矫正方式的满意度增加,在运动、对眼部健康和花费的担忧方面明显改善。     

Binocular vision impairment after refractive surgery

PURPOSE: To illustrate the need for an accurate preoperative orthoptic examination to prevent postoperative changes in binocular vision. SETTING: Department of Ophthalmology, University Hospital Antwerp, Edegem, Belgium. METHODS: Five patients presenting major subjective complaints after refractive surgery were analyzed. RESULTS: In 1 patient, a latent N IV palsy decompensated after laser in situ keratomileusis (LASIK) in the more myopic eye to achieve monovision. A second patient, operated on for N IV palsy 10 years earlier, presented a recurrence of the palsy after bilateral LASIK for myopia. The third patient complained of discomfort in binocular vision caused by aggravation of a preexisting intermittent esotropia that worsened after LASIK for hyperopia. The fourth patient complained of diplopia after LASIK in the highly anisometropic and exotropic eye. The fifth patient experienced a decrease in fusion and stereopsis at the time he became anisometropic after bilateral LASIK. CONCLUSIONS: Special care should be taken of patients who have a preoperative history of strabismus surgery, an overcorrection or undercorrection in 1 or both eyes, or anisometropia and of those who are unhappy with contact lenses. An orthoptic examination should be done with and without spectacle correction to detect underlying vertical phorias. Intended monovision should be examined initially using contact lenses.     

Contact lens status in ametropia correction:a prospective study

Background : Optical devices such as spectacles and contact lenses have been used to correct ametropia for many years. Recently, surgical means of correction such as photorefractive keratectomy have been introduced. All of these forms of correction are readily available in Saudi Arabia. The purpose of this study was to determine the proportion of contact lens use in ametropia correction. This survey also presents an insight into patient satisfaction with their correction and their willingness to change to another form of correction in the future. This will serve as a guide for eye care practitioners and manufacturers. Method : Five hundred and seventy four subjects responded to questionnaires randomly distributed among hospital patients, students and staff of King Saud University. Results : Data revealed that spectacle wearers constituted 74.5 per cent of the sample population, followed by contact lens wearers (21.8 per cent) and those who had undergone photorefractive keratectomy (3.7 per cent). On the whole, 50 per cent of the population sample would change to another form of correction. Among contact lens wearers, 9.5 per cent would prefer to change to PRK and 0.4 per cent to spectacles, while 17.9 per cent of spectacle wearers would consider changing to contact lenses. Conclusion : Contact lenses constitute a minor proportion of ametropia corrections. Spectacles remain the most popular form of ametropia correction at the moment, but for the future, there is greater tendency towards contact lenses and PRK.