Introduction
Daily disposable lenses are one of the two versions of true, single-use-only, contact lenses – the other being extended-wear lenses.
Daily disposable lenses first became available in 1994. The premier daily disposable lens was launched in the United Kingdom (later this was sold to Bausch & Lomb) and Johnson & Johnson released the 1-Day Acuvue daily disposable lens in western regions of the United States at around the same time ( ). Since their release in the mid-1990s, daily disposable lenses rapidly gained worldwide acceptance. This trend has continued into the 21st century, as indicated in Fig. 19.1 , which illustrates the extent of daily disposable lens prescribing as a percentage of all soft lenses fitted in 17 nations between 2000 and 2020 ( ).
Numerous brands of daily disposable hydrogel lenses have entered the market over the past two decades, and in 2021 the four major global contact lens companies produced 14 brands of spherical, 9 brands of toric, 6 brands of multifocal and 1 brand of cosmetic coloured daily disposable lenses, in both hydrogel and silicone hydrogel materials ( ).
Usage of daily disposable lenses varies widely among nations, as shown in Fig. 19.2 . Between 2015 and 2019 daily disposable lenses represented over 40% of all soft contact lenses prescribed in 17 out of 45 nations surveyed ( ).
The reasons for the discrepancy in the extent of daily disposable lens prescribing between countries may relate to a number of factors, such as differences in the retail cost to lens wearers, profit margins enjoyed by practitioners, extent and effectiveness of distribution and marketing, and the local influence of opinion leaders. Cost of product is perhaps the most significant factor. It has been demonstrated that in two markets – Australia ( ) and the United Kingdom ( ) – the annual cost of wearing daily disposable lenses on a full-time basis is greater than that for reusable lenses, irrespective of lens design (i.e. spherical, toric and multifocal). This cost analysis is still valid in 2021. Although daily disposable lenses are more cost-effective compared with reusable lenses when worn on a part-time basis, it is likely that the overall prescribing of daily disposable lenses is driven by the perceived costs incurred for full-time wear ( ).
reported that the proportion of daily disposable lens fits (as a function of all soft lens fits) was positively related to the gross domestic product at purchasing parity per capita for the year 2011 ( r 2 = 0.55, P < .0001). When this analysis was updated for 45 nations surveyed between the years 2015 and 2019 ( Fig. 19.3 ), another highly statistically significant correlation was found ( P <.0001), albeit with more variance (i.e. a lower r 2 value of 0.39). That is, between 2015 and 2019, 39% of the variance in daily disposable prescribing between nations can be explained by the gross domestic product at purchasing parity per capita.
The demonstration of a strong relationship between the extent of daily disposable lens fitting and the gross domestic product at purchasing parity per capita (essentially a measure of the average wealth of individuals in a nation) supports the hypothesis that the extent of daily disposable lens prescribing is driven to a large extent by cost considerations. However, the above analyses suggest that this ‘cost driver’ for purchases of daily disposable contact lenses has weakened over the past 4–8 years.
Patterns of Wear
The influence of contact lens type on wearing frequency was investigated by based upon data derived from 25,575 contact lens fits undertaken in the United Kingdom between 1996 and 2020. The wearing patterns of those fitted with the following three categories of lenses were analysed: rigid, soft daily disposable and soft monthly reusable. The proportion of all fits in relation to the number of days lenses are worn each week is shown in Fig. 19.4 for each of these three categories. For rigid and soft monthly reusable lenses, there is an increasing proportion of fits being used for a greater number of days each week; this distribution is more sharply skewed in respect of rigid lens wearers.
The distribution for daily disposable lens wearers appears to be bimodal, with peak wearing frequencies at 2 and 7 days per week. This indicates that patients wearing this lens type have a greater tendency to be ‘part-time’ wearers compared with patients wearing less frequently replaced lenses. If ‘part-time wear’ and ‘full-time wear’ are defined as lenses being worn 1–3 and 4–7 times per week, respectively, then this data shows that 54% of those wearing daily disposable lenses do so on a part-time basis.
surveyed lens-wearing patterns in Australia, Norway, the United Kingdom and the United States and reported that, overall, 59% of participants reported wearing their lenses for 7 days per week. A significantly higher proportion of participants reported wearing lenses 7 days per week in the United States and Norway (64% and 71%, respectively) than in Australia and the United Kingdom (35% and 41%, respectively; P < .001).
The bimodal distribution of daily disposable lens-wearing frequency shown in Fig. 19.4 may reflect two distinct approaches to lens wear. The peak around 1–3 days per week self-evidently represents those using daily disposable lenses on a part-time basis. Indeed, daily disposable lenses are a logical choice for part-time wear because of increased convenience and enhanced safety, as discussed below. Full-time wear of daily disposable lenses is an expensive option compared with full-time wear of 2-weekly or monthly disposable lenses, and those who wear daily disposable lenses full time (wearing lenses 4–7 days per week) have presumably determined that the enhanced safety and convenience of this approach are worth the higher cost.
Clinical Performance
If the clinical benefits of planned replacement are accepted, then it would seem logical to change lenses as often as possible. Soon after daily disposable lenses entered the market in the mid-1990s, the benefits of this replacement modality compared with the reusable and nonplanned replacement lenses prescribed prior to this time were stark. For example, reported that daily disposable lens wearers had fewer symptoms, fewer deposits, better vision, fewer tarsal abnormalities, fewer ocular complications and better overall satisfaction than patients using conventional lenses. found that lens comfort, subjective symptoms (i.e. dryness, soreness, scratchiness) and vision were significantly better with daily disposable lenses compared with the previously used lens replacement modality (42% of patients were previously using monthly or fortnightly replacement). observed a 4.9% incidence of complications for daily disposable lens wearers compared with 8.5% for conventional daily-wear soft lens wearers. In a comparison of 2-weekly replacement lenses with daily disposability lenses, noted that, at the very least, patients wearing single-use lenses benefitted from greater convenience and comfort.
Subsequent studies showed similar benefits ( ). An extensive evaluation of the ocular response to neophyte patients fitted with one brand of silicone hydrogel daily disposable lenses (Acuvue TruEye, Johnson & Johnson Vision Care) demonstrated excellent comfort and vision with minimal alterations to ocular physiology ( ). also noted good subjective and objective responses to daily disposable lenses, but observed that different contact lens materials and designs elicited different ocular and patient responses. reported that comfort and vision with some contemporary daily disposable contact lenses are indistinguishable from nonwearing emmetropes.
demonstrated that when patients switched to daily disposable lenses after having used 2-weekly replacement lenses there was a reduction in subjective complaints of dryness, and objectively a significant reduction of superficial punctate keratitis was observed at follow-up examinations.
assessed the influence of end-of-day silicone hydrogel daily disposable contact lens fit on ocular comfort, physiology and lens wettability. Among the three lenses tested, objective lens fit changed between 8 and 12 hours of lens wear. The authors suggested that the weak correlation in individual lens fit between brands indicates that fit is dependent on more than ocular shape. Consequently, substitution of a different lens brand with similar parameters will not necessarily provide a comparable lens fit.
compared the clinical performance of three silicone hydrogel daily disposable lenses and found that they all performed well, with only slight differences in physiological responses between lenses. They found no difference between asymptomatic and symptomatic wearers with regard to ocular response and contact lens-related parameters and concluded that silicone hydrogel daily disposable lenses are an excellent contact lens modality for the symptomatic patient.
The obvious advantage offered by daily lens disposal is a fresh, sterile pair of lenses for wearing each day. If cost was not a limiting factor, then it could be argued that all daily-wear soft lens patients should be using this modality.
Advantages From the Perspective of Practitioners
Specific advantages of daily disposable lenses from the standpoint of the practitioner include the following:
- •
Less patient education time is required (virtually no advice needs to be given about lens care).
- •
The absence of a lens storage case from the regimen is beneficial, given the role that a lens case can play in the development of corneal infiltrative events (CIEs) and ocular infection ( ).
- •
Less professional ‘chair time’ is required because there are no problems relating to lens care solutions (e.g. toxicity or sensitivity reactions) ( ) and fewer ocular complications of lens wear compared with that experienced with reusable lenses ( ).
- •
Less ancillary staff time is required because there is no need for discussions and sales relating to lens care products.
- •
There are no disputes concerning wearing frequency (e.g. some patients might argue that a lens designed for monthly replacement but only worn once a week can last for 3 months).
- •
Daily disposability is more hygienic for intermittent wearers, as long-term storage problems are eliminated, making daily disposability the replacement modality of choice for such patients.
- •
The regular supply of large numbers of lenses required for daily lens disposal can be leveraged from a practice management standpoint by introducing strategies such as monthly payment plans ( ) and subscriber membership systems ( ), which are considered to be attractive business models and practice builders ( ).
Advantages From the Perspective of Lens Wearers
Advantages of daily disposable lenses from the perspective of lens wearers include:
- •
There is no need to be concerned with lens care systems, although it is desirable for daily disposable lens wearers to have a supply of sterile saline or multipurpose solution for lens rinsing if there is discomfort during, or soon after, lens insertion.
- •
There are no anxieties about lost or damaged lenses.
- •
Daily disposable lenses are convenient and compact for travel; there is no need to carry bulky lens care solutions.
- •
Daily disposable lenses are highly cost effective in that lens wear is directly linked to lens cost (unlike, say, monthly disposable lenses that may be worn only a few times during the month).
- •
Daily disposable lenses are excellent for monovision correction of presbyopia, as it is easy to alternate between various lens combinations (e.g. two distance lenses versus monovision, depending on the need; see Chapter 22 ).
- •
Daily disposable lenses are easy to discard (‘any time, any place, without a case’).
- •
Visual performance remains good throughout the day ( ).
- •
Compliance is easier because there are fewer instructions to remember ( ).
Since daily disposable contact lenses eliminate the need for cleaning and disinfection, they should be strongly considered as a contact lens treatment option for children. demonstrated that 8- to 11-year-old children are able to care for daily disposable contact lenses independently and wear them successfully. reported similar findings for children aged 13–19, and observed no contact lens-related serious adverse events or significant biomicroscopy changes among 69 children aged 8–12 who wore daily disposable lenses over a 6-year period. Certainly, observed that children aged 6–12 years are fitted with the highest proportion of daily disposable lenses and have the highest rate of fits for part-time wear, compared with infants, teenagers and adults ( ).
Disadvantages
Potential disadvantages of daily disposable lenses include the following:
- •
Patients may be noncompliant by way of reusing lenses. reported that, of patients who were given correct instructions, 12% and 13% reused their daily disposable lenses in the United States and Canada, respectively. Reuse of lenses poses an important risk for daily disposable lens users because they are unlikely to have received proper training in cleaning and disinfection of lenses and do not use a lens case or disinfecting solutions ( ).
- •
Practitioners have been known to sanction patients to reuse daily disposable lenses. According to , 4% and 6% of practitioners in the United States and Canada, respectively, recommended that their patients reuse daily disposable lenses.
- •
New daily disposable lens wearers who have not previously worn other lens types – and have thus never been instructed in lens care – may adopt unwise practices through ignorance (e.g. storing a lens overnight in tap water).
- •
Because of the low unit cost of lenses, patients may think it is all right to give lenses to friends to try.
Comfort Enhancement Strategies
A number of strategies have been adopted by different manufacturers to enhance the comfort of daily disposable lenses. For example, Alcon has modified Dailies All Day Comfort lenses to include additional, nonfunctional, polyvinyl alcohol (PVA). PVA is a successful tear film stabilizer and is widely used in comfort drops. According to , release of additional nonfunctionalized PVA appears to enhance comfortable contact lens wear. Dailies AquaComfort Plus lenses contain hypromellose (short for hydroxypropyl methylcellulose), polyethylene glycol and dual-molecular-weight PVA, as comfort-enhancing agents; such strategies have been shown to be clinically effective in enhancing comfort ( ).
Vistakon have incorporated proprietary wetting agents into their daily disposable lenses. 1-Day Acuvue Moist contains Lacreon, and Acuvue TruEye contains Hydraclear, although the detailed chemical formulations of these agents are not in the public domain.
The use of daily disposable lenses has been shown to be an effective strategy for managing allergy-suffering contact lens wearers. monitored subjective comfort and slit-lamp findings with daily disposable contact lenses in a population of allergy sufferers during periods when allergen levels were elevated. Sixty-seven per cent of subjects agreed that the daily disposable lenses provided improved comfort when compared with the lenses they wore prior to the study, versus 18% agreeing that the new pair of habitual lenses provided improved comfort. The daily disposable lenses also resulted in a greater improvement in slit-lamp findings from baseline than new habitual lenses.
As an additional strategy for alleviating troublesome allergy-related symptoms, daily disposable lenses are now available that contain slow-release anti-allergy drugs. demonstrated the clinical efficacy of a daily disposable contact lens-based drug delivery system for therapeutic delivery of the antihistamine ketotifen (Acuvue Theravision, Johnson & Johnson Vision) (see [CR] ).
Manufacturing Reliability
examined 150 −3.00-D lenses of each of the first three brands of daily disposable lenses on the market and reported an overall high degree of accuracy and reproducibility ( Fig. 19.5 ). They found that, with one inconsequential exception, all measured parameters of all three lens types examined fell well within clinically acceptable limits for providing wearers of these lenses with consistent vision and fit.
