Daysoft Contact Lens

nedmundo

It's interesting how many have commented on 'faulty batches' on this forum, relative to the number of actual posters on the subject.

Unity

nedmundo wrote: »

It's interesting how many have commented on 'faulty batches' on this forum, relative to the number of actual posters on the subject.

Staying with the topic of this thread though, which is Daysoft's customer service - even more interesting are the positive comments on the resolution of these problems. I haven't experienced any problems with their lenses unlike Acuvue and Frequency 55 :rolleyes:.

Auzelia

I worked in a call centre for a contact lens company (apollo optic) germany company.
and we where under NO CIRCUMSTANCES allowed to change customers contact lens type, rx, base curve, cylinder, (anything really) without the go ahead from their optician.

olly300

Auzelia wrote: »

I worked in a call centre for a contact lens company (apollo optic) germany company.
and we where under NO CIRCUMSTANCES allowed to change customers contact lens type, rx, base curve, cylinder, (anything really) without the go ahead from their optician.

You are not an optician so obviously you can't do that.

Auzelia

but even if I was an optician I still would not be allowed to change it without seeing the patient first.

It all fair in saying that there is only a slight adjustment.
But if you change one part of a lens, then you most likely have to make a slight adjustment else where.

esp. with toric lenses.

Unity

Auzelia wrote: »

but even if I was an optician I still would not be allowed to change it without seeing the patient first.

It all fair in saying that there is only a slight adjustment.
But if you change one part of a lens, then you most likely have to make a slight adjustment else where.

esp. with toric lenses.

Not however with water content - all my prescription fittings are the same, the change in water content just proves to be more comfortable in some cases and certainly in mine, because less moisture is being lost from the eyes. I didn't even need to pay to try them, I received a whole month's supply free of charge. Their customer service is second to none:T.

nedmundo

Changing water content can significantly affect the fitting characteristics of the lens. Check this out!



Daily disposable soft lens diameters
This article is best viewed in a PDF Format.

View PDF

All of the currently marketed daily disposable soft lenses are only available in a single diameter. However, diameter is an important parameter in relation to optimising lens fit.

Lenses which are too small fail to give complete corneal coverage and result in discomfort and peripheral corneal staining. However, lenses which are too large exert more pressure at the periphery - due to greater bending forces - which can lead to discomfort and indentation of the bulbar conjunctiva.
In a typical population, corneal diameters vary by about 1.5mm,1 whereas the range of diameters on offer with daily disposable lenses is relatively narrow - 13.8 to 14.3mm. In fact, all but a few designs are labelled as 14.2mm. However, previous work has shown that measured diameter does not always correspond to labelled diameter because of the effects of pH, osmolarity and temperature. In particular, raising the temperature of the lens from room to eye temperature can have a significant effect.2-3
It has been suggested that daily disposable lenses are 'commodity products' and readily interchangeable. At least one internet supplier of daily disposable lenses encourages the switching of patients from their existing soft lenses to an alternative daily disposable lens without the need for a contact lens check.4 For this to be feasible there would need to be close consistency of on-eye diameter between the two products to ensure the same corneal coverage.
The purpose of this study was to evaluate the actual diameter of currently available daily disposable lenses and their change in diameter when raised to eye temperature.
Methods
The diameters of 13 daily disposable lens brands currently available in the UK (Table 1) were measured at two different temperatures: room temperature and eye temperature.5 Eighteen of each type of lens were measured: six lenses in three powers (-1.00, -3.00 and -6.00D). The measurements were taken using a temperature-controlled Chiltern Lens Analyser (Optimec, Malvern, UK). Two sets of measurements were recorded: at room temperature (20°C) and at eye temperature (34°C). Buffered unpreserved saline was circulated in the measurement cell. In both cases the temperature of the cell was regularly checked and appropriate action taken to avoid taking measurements outside of a narrow range of temperature (±1°C).
Prior to measurement, the lenses were allowed to settle in the wet cell for approximately two minutes. After the settling period, a diameter measurement was taken, the lens was then agitated, allowed to resettle and the measurement repeated. The diameter measurements were taken at the two and eight o'clock positions and an average of these two reading taken. The instrument incorporates a graduated display in steps of 0.1mm. However, it was possible to carry out measurements to the nearest 0.05mm. All measurements were repeated three times and the mean calculated.
Results
Eight of the 13 lenses in this study had a labelled diameter of 14.2mm one lens (New Day) was labelled larger and four smaller than this. All of the lens diameters measured at room temperature were within 0.2mm of labelled diameter, ie within ISO tolerance 6 (Table 1). The range of measurements at room temperature for a given lens varied from the labelled diameter by 0.05mm with Focus Dailies to 0.20mm for New Day. When re-measured at eye temperature, each of the lenses showed a mean reduction in overall diameter (Fig 1). This shrinkage ranged from 0.12mm with Clearlab 1Day to 0.83mm with Daysoft 72.
Discussion
The results confirm that comparing labelled diameters is unhelpful, and in some cases misleading, for predicting the on-eye performance of current daily disposable soft lenses. This is highlighted by the fact that lenses labelled 14.2mm ranged in diameter from 13.5mm to 14.1mm when measured at eye temperature. Paradoxically, the lens that showed the largest diameter at room temperature (Daysoft 72) was the smallest lens at eye temperature (14.4 vs 13.5mm). Soft lens diameter is arguably a more critical parameter than BOZR since typical variations in the latter have little effect on lens fit.7 This lack of clarity in the parameter of lens diameter is therefore particularly regrettable.
When comparing the lenses in this study, the eye temperature diameters fall roughly into three categories which can be described as 'small' (13.5-13.7mm), 'medium' (13.9mm) and 'large' (14.1-14.2 mm). It is helpful for practitioners to be aware of this categorisation, particularly when selecting lenses for corneas at either end of the size range. Given that the actual cornea is approximately 1.3mm larger than the visible iris diameter, small diameter lenses are rarely suitable for larger corneas.1 A cornea with horizontal visible diameter of 12.0 mm, therefore, might be expected to have an actual diameter of about 13.3mm which is close to the diameter of the smallest lens measured here, thus, leaving little scope for lens movement.
The three lenses showing the greatest shrinkage when raised to eye temperature were all FDA Group 4 lenses (SofLens, Daysoft 58 & 72). This is consistent with previous work investigating the temperature sensitivity of non-ionic lenses.8-10
The three lens types showing the least shrinkage (Bioclear, Clear 1-day and Proclear) use materials which are claimed to be biomimetic and, as a result, dehydration resistant. The differences in shrinkage between materials can be explained by differences in the fraction of bound (or non-freezing) water. Those materials, such as omafilcon A, with relatively strong interaction with water have a relatively high fraction of bound water.
Two of the lenses in this study (Daysoft 58 and 72) are marketed direct to the public and are claimed to be interchangeable with most other disposable lenses without recourse to refitting. However, the fact that, at eye temperature, these are significantly smaller than several of the other lenses casts some doubt on this claim. For example, only a limited number of large corneas successfully fitted with Proclear (14.2mm) are likely to achieve full corneal coverage with Daysoft 72 (13.5mm). Clearly, other variables such as lens design and material modulus also affect lens fit and further complicate the interchangability of lenses.
Two lens brands (Dailies, 1 Day Acuvue) are available with and without wetting agents. In both cases, the amount of shrinkage was similar between lenses with and without the wetting agents.
Conventionally, soft lens diameter is measured at room temperature (20°C) during manufacture, as it is easier to maintain wet cells at this rather than eye temperature. A preferable approach with total diameter might be for manufacturers to specify soft lens diameter based on eye temperature as this is more easily related to the on-eye performance. This would not prevent routine checking at room temperature as a simple conversion factor could be used between the two measurements. However, as with oxygen permeability, it would be necessary to indicate the measurement temperature so as to avoid confusion.
This evaluation did not take into account differences between lenses with respect to sagittal depth which can vary widely in lenses of similar diameter. Burki noted a difference in sagittal depth of nearly 1.0mm for lenses of similar labelled diameter and BOZR.11 Due to lens wrapping, these differences are a potential further source of variation in on-eye diameter.12 Further work in this area would be useful in relating clinical performance more closely to soft lens parameters. Similar information on other categories of lens would also be useful (eg silicone hydrogels) and this will be the subject of future reports.
In conclusion, total diameter is an important parameter in relation to successful soft lens fit. However, because of temperature induced changes, on-eye diameter is not easily predictable from the labelled diameter. More information is needed to help practitioners select the appropriate lens type.
Acknowledgements
This study was funded by Visioncare Research which has, at various times, received sponsorship from: Bausch & Lomb, Ciba, Clearlab, Johnson & Johnson Visioncare, and Sauflon. I am grateful to Shaun Peters for undertaking the measurements.
References

1. Martin DK, Holden BA. A new method for measuring the diameter of the in vivo human cornea. Am J Optom Physiol Opt, 1982 59:436-441.
2. Martin DK, Holden BA. Variations in tear fluid osmolality, chord diameter and movement during wear of high water content hydrogel contact lenses. Int Cont Lens Clin, 10: 332-41 1983.
3. McNamara NA, Polse KA, Brand RJ, Graham AD, Chan JS, McKenney CD. Tear mixing under a soft contact lens: Effects of lens diameter. Am J Ophthal, 1999 127: 659-665.
4. Bennett C. Taking a bet on the net. Optician, 2007 234(6113):14-15.
5. Efron N, Young G, Brennan N. Ocular surface temperature. Current Eye Res, 1989 8:901-906.
6. ISO 18369-2 2006 Optics and optical instruments - Contact lenses - Part 2: Tolerances.
7. Young G, Holden B, Cooke G. The influence of soft contact lens design on clinical performance. Optom Vis Sci, 1993 70:394-403.
8. McCarey BE, Wilson LA. pH, osmolarity and temperature effects of the water content of hydrogel lenses. Cont lens Intra Lens J, 1982 8: 158-67.
9. Kohler JE, Flanagan GW. Clinical dehydration of extended wear lenses. Int Cont Lens Clin, 1985 12:152-160.
10. Gundel RE, Cohen HI. Dehydration induced parameter changes. Int Cont Lens Clin, 1986 2:3114.
11. Burki E. Erweiterte anpassm oglichkeiten von austauschlinsen. Contactologia, 1997 19:108-112.
12. Young G, Grewel I. How relevant are the labelled diameters of soft lenses? Optom Vis Sci, 1999 76(12S):171.
13. Graeme Young is managing director of Visioncare research, an independent clinical research organisation specialising in eye care research

Unity

nedmundo wrote: »

Changing water content can significantly affect the fitting characteristics of the lens. Check this out!

Results
Eight of the 13 lenses in this study had a labelled diameter of 14.2mm one lens (New Day) was labelled larger and four smaller than this. All of the lens diameters measured at room temperature were within 0.2mm of labelled diameter, ie within ISO tolerance 6 (Table 1). The range of measurements at room temperature for a given lens varied from the labelled diameter by 0.05mm with Focus Dailies to 0.20mm for New Day. When re-measured at eye temperature, each of the lenses showed a mean reduction in overall diameter (Fig 1). This shrinkage ranged from 0.12mm with Clearlab 1Day to 0.83mm with Daysoft 72.

Acknowledgements
This study was funded by Visioncare Research which has, at various times, received sponsorship from: Bausch & Lomb, Ciba, Clearlab, Johnson & Johnson Visioncare, and Sauflon. I am grateful to Shaun Peters for undertaking the measurements.

Whilst I can see that this may have some relevance to someone changing between brands of contact lenses, it doesn't apply here. I had, as previously stated, already been fitted with Daysoft lenses by a qualified optometrist, with measurements checked prior to - and at the end of an extended period of wear. The optometrist was happy with the fitting of the lenses and I was happy with the visual acuity and comfort. Result! :T

The quoted research is limited as it only shows comparisons between Daysoft and other makes, but fails to make any direct comparison between Daysoft 72 and Daysoft 58, therefore it is irrelevant here. I am quite happy to rely on the previously quoted assurance of the qualified optometrist at Daysoft who confirmed the following: -

"I am very happy to give you the reassurance you need as simply changing from daysoft 72 to daysoft 58 is not going to give a problem – the two are interchangeable with some wearers finding no difference whichever they use but others such as yourself finding they prefer either 58 or 72.
I think from what you say your original daysoft lenses may have been prescribed before daysoft 58 was introduced and as daysoft lenses are generally available via Independent opticians and some websites rather than the Optical chain practices perhaps that was why your latest Optician was not aware of them – although even if an outlet does not sell a particular brand usually practitioners will keep themselves aware of the various lenses that are on the market."

It is of course worthwhile noting the named sponsors of the quoted research, since they are hardly impartial , or acting out of altruism,:rolleyes: they are in fact, correct me if I am wrong - makers of contact lenses with a vested interest in denouncing competition?

Keeping on topic, it is interesting however, to note the number of people who comment on these forums regarding the excellent customer service by Daysoft, since they are always prompt in despatching the lenses and always very efficient in dealing with queries. If customers were unhappy with the corrective properties of their lenses, or they were uncomfortable to wear, they would undoubtedly vote with their feet. Perhaps these are among the reasons, including of course 'cost' why people are changing to Daysoft .

Jennip37

Just placed my first order with Daysoft. Have just been prescribed Air optix night and day and came across the Daysoft website whilst I was surfing for the best price for Air optix. Sounds too good to be true but for a tenner thought I'd give it a go. Daysofts website recommended 72% but I suffer from dry eye so I'll give them a go and see how I get on.

Sam-Barr

Have just ordered, will let you know how I get on :-)

Judging by their phone number, their contact centre is not far from my home lol