The effect of variably tinted spectacle lenses on visual performance in cataract subjects

Photokeratitis induced by ultraviolet radiation in travelers: A major health problem

Ultraviolet (UV) irradiation is one of the several environmental hazards that may cause inflammatory reactions in ocular tissues, especially the cornea. One of the important factors that affect how much ultraviolet radiation (UVR) humans are exposed to is travel. Hence, traveling is considered to include a more acute UVR effect, and ophthalmologists frequently evaluate and manage the ocular manifestations of UV irradiation, including UV-induced keratitis. The purpose of this paper is to provide an evidence-based analysis of the clinical effect of UVR in ocular tissues. An extensive review of English literature was performed to gather all available articles from the National Library of Medicine PubMed database of the National Institute of Health, the Ovid MEDLINE database, Scopus, and ScienceDirect that had studied the effect of UVR on the eye and its complications, between January 1970 and June 2014. The results show that UVR at 300 nm causes apoptosis in all three layers of the cornea and induces keratitis. Apoptosis in all layers of the cornea occurs 5 h after exposure. The effect of UVR intensity on the eye can be linked to numerous factors, including solar elevation, time of day, season, hemisphere, clouds and haze, atmospheric scattering, atmospheric ozone, latitude, altitude, longitudinal changes, climate, ground reflection, and geographic directions. The most important factor affecting UVR reaching the earth's surface is solar elevation. Currently, people do not have great concern over eye protection. The methods of protection against UVR include avoiding direct sunlight exposure, using UVR-blocking eyewear (sunglasses or contact lenses), and wearing hats. Hence, by identifying UVR intensity factors, eye protection factors, and public education, especially in travelers, methods for safe traveling can be identified.

Effect on falls of providing single lens distance vision glasses to multifocal glasses wearers: VISIBLE randomised controlled trial

OBJECTIVE

To determine whether the provision of single lens distance glasses to older wearers of multifocal glasses reduces falls.

DESIGN

Parallel randomised controlled trial stratified by recruitment site and source of referral, with 13 months' follow-up and outcome assessors blinded to group allocation.

SETTING

Community recruitment and treatment room assessments in Sydney and Illawarra regions of NSW, Australia.

PARTICIPANTS

606 regular wearers of multifocal glasses (mean age 80 (SD 7) years). Inclusion criteria included increased risk of falls (fall in previous year or timed up and go test >15 seconds) and outdoor use of multifocal glasses at least three times a week.

INTERVENTIONS

Provision of single lens distance glasses with recommendations for wearing them for walking and outdoor activities compared with usual care.

MAIN OUTCOME MEASURES

Number of falls and injuries resulting from falls during follow-up.

RESULTS

Single lens glasses were provided to 275 (90%) of the 305 intervention group participants within two months; 162 (54%) of the intervention group reported satisfactory use of distance glasses for walking and outdoor activities for at least 7/12 months after dispensing. In the 299 intervention and 298 control participants available to follow-up, the intervention resulted in an 8% reduction in falls (incidence rate ratio 0.92, 95% confidence interval 0.73 to 1.16). Pre-planned sub-group analyses showed that the intervention was effective in significantly reducing all falls (incidence rate ratio 0.60, 0.42 to 0.87), outside falls, and injurious falls in people who regularly took part in outside activities. A significant increase in outside falls occurred in people in the intervention group who took part in little outside activity.

CONCLUSIONS

With appropriate counselling, provision of single lens glasses for older wearers of multifocal glasses who take part in regular outdoor activities is an effective falls prevention strategy. The intervention may be harmful, however, in multifocal glasses wearers with low levels of outdoor activity.

TRIAL REGISTRATION

Clinical trials NCT00350389.

Football players' contrast sensitivity comparison when wearing amber sport-tinted or clear contact lenses

BACKGROUND

Many experiments are conducted each year in the sporting world to try and improve the existing technology and equipment in an effort to positively influence athletic outcomes. These studies, at times, are concerned about vision and how athletes can improve their visual inputs to respond most advantageously. Sports vision aids are becoming a more integral part of an athlete's equipment. Recently, sport-tinted contact lenses have become available to athletes of various sports. The purpose of this study was to compare football players' contrast sensitivity when wearing specially designed sport-tinted contact lenses to that when wearing clear contact lenses or no contact lenses in the case of an emmetropic athlete.

METHODS

Participants were fitted with either clear contact lenses or sport-tinted contact lenses. Spherical equivalent refractions were used because sport-tinted contact lenses are not currently available for astigmatic prescriptions. Contrast sensitivity was measured monocularly on a sine-wave grating chart of 4 spatial frequencies, each with decreasing contrast. Testing then was repeated with the other contact lens. Comparison was made to determine if statistically or clinically significant data would support the claim of increased contrast enhancement for the athletes while wearing the sport-tinted contact lenses.

RESULTS

Thirty-five subjects participated (35 left eyes), ranging in age from 18 to 32 years. All subjects were professional or collegiate football players. Testing done at 3, 6, 12, and 18 cycles per degree (cpd) of spatial frequency found statistically significant improvement with the sport-tinted contact lenses where P < 0.05. With an examination of the emmetropic-only subgroup, these same results were confirmed at 3 and 6 cpd. Although most of the results were statistically significant, it is questionable whether there is any clinically significant improvement in contrast enhancement while wearing these lenses.

CONCLUSION

Sport-tinted contact lenses appear to have a statistically significant effect on contrast sensitivity when worn by a relatively low astigmatic or spherically refracted patient. These results also hold true for enhancing sensitivity in the emmetropic athlete. This information is dampened, however, when considering clinical significance. Overall, there does not appear to be overwhelming evidence that the sport-tinted lenses provide any clinically significant difference when considering contrast enhancement. There are always exceptions to any study; therefore, each case would have to be evaluated by the individual practitioner and the athlete.

Sunglasses- and photochromic lens-wearing patterns in spectacle and/or contact lens-wearing individuals

PURPOSE

To determine differences in wearing patterns of sunglasses and/or photochromic lenses in spectacle and contact lens wearers, to assess patient awareness of the indications for the use of tinted lenses, and to identify wearers' lens tint preferences.

METHODS

A total of 100 individuals wearing some combination of contact lenses and spectacles participated in a survey questionnaire composed of 14 questions. Participants were asked if they used sunglasses/photochromic lenses, why they used them, their preferred lens tints, and temporal and seasonal patterns of use. They were also queried on their awareness of the potential adverse effects of ultraviolet radiation (UVR) exposure on the health of the eye and appropriate protective measures. Participants were categorized based on their use of spectacles and/or contact lenses. Demographic characteristics of sex and age were taken into account for the analysis. The data were imported and analyzed using commercial statistical analysis software.

RESULTS

A total of 52% of the participants wore spectacles exclusively, while 48% wore some combination of spectacles and contact lenses. In the spectacle group, 36% and 20% wore sunglasses and photochromic lenses, respectively. In the contact lens group, 20% and 10% wore sunglasses and photochromic lenses, respectively. Overall gray was the preferred lens tint, especially in the younger age groups. Summer was the primary season for use of tinted lenses. Approximately one-third of the sample were not aware of the UVR protective properties of their eyewear. A total of 77% believed that UVR could be harmful to the eyes, but only a small percentage of the participants wore sunglasses or photochromic lenses specifically for UVR protection.

CONCLUSION

There was no statistically significant difference (P = 0.07) for preference between sunglasses versus photochromic lenses and in seasonal patterns for tinted lens use among spectacles and contact lens wearers. Spectacle wearers (as well as contact lens wearers) used sunglasses more than photochromic lenses (P = 0.004). Most of the participants wore sunglasses in the summer and to protect their eyes from bright light. Overall gray was the preferred lens tint. Potentially adverse effects of UVR exposure to the eye and the importance of proper UVR eye protection were not generally appreciated by the subjects queried.