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Tuesday / August 16.
HomemipatientPrescribe the Lens to the Patient

Prescribe the Lens to the Patient

These days it is easy to fall into the trap of fitting the patient to the contact lens, rather than fitting the contact lens to the patient writes Jessica Chi.

We are lucky to be practising optometry in a time where lens options seem endless. Within soft contact lenses, we have sphere powers up to +/-20, cylinder powers up to -5.75, multifocal lenses with up to eight different near additions, and these are just the disposable options. We also have multitudes of options in single use lenses (just thinking about the number of SKUs the companies must have to keep inventory makes my head spin). To top it off, we have four major players each with their own portfolios, so if a patient doesn’t suit one design, there’ll almost definitely be another option.

I often get asked ‘which lens do I think is best,’ to which I always answer ‘for what’ or ‘it depends’. I don’t have a favourite lens; I don’t have a favourite company. I understand the benefits and downfalls of the lenses and I try my best to match the lens I think is best for the patient. Plus, making sure we use lenses across the companies creates competition, and competition is healthy.

Recently I refitted a 51-year-old female patient who wished to obtain single vision near spectacles to use in adjunct to her contact lenses. IM was wearing Alcon Night and Day contact lenses on a 30-day extended wear (EW) basis. For the most part she managed well with her contacts, however recently she had been noticing some lens awareness and had even lost a couple of lenses. Additionally, she had experienced occasional cloudiness in her vision, which she managed by using Blink n Clean lubricating drops. She reported that her vision seemed fine for distance, and was using +1.50DS magnifiers for near.

IM had been wearing soft contact lenses since age 45, and had been in extended wear from the beginning as she struggled with insertion and removal.

Examination and Assessment

Vision with IM’s present contact lenses of prescription R 8.4/13.8/+4.75 and L 8.4/13.8/+3.75 was R 6/12 and L 6/9. This could be corrected to R 6/7.5+ and L 6/6= with an over-refraction of R +0.50/-1.00×105 and L +0.75/-1.50×118. A near addition of +2.25DS enabled N5 at near.

Examination of the contact lenses revealed little to no lens movement on blink, with mild-moderate lipid deposition on the lenses.

Removal of the contact lenses revealed mild superior punctate keratitis and moderate contact lens papillary conjunctivitis L>R (refer figure 1).

Subjective refraction gave R +4.75/-0.50×96 (6/7.5) and L +3.50/-1.00×120 (6/6). A near addition of +2.25DS enabled N5 at near.

I explained that contact lens over-use had led to her papillary conjunctivitis, which was causing the excess deposition on her lenses, leading to reduced vision and comfort. Despite this, IM was keen to pursue continuous wear (CW) due to the freedom she experienced with this modality. She was adamant that she was ‘happy’ with her present situation.

While IM was ‘happy’ in her extended wear lenses, and ‘happy’ to wear spectacles on top, I was confident I could make her ‘happier’. Throughout the consultation, we discussed various contact lens options. She told me that she had tried mono-vision in the past unsuccessfully and was interested to hear of multifocal options. However, once I assessed her vision, finding contact lens acuity of only R 6/9 and L 6/12 with single vision lenses, I wasn’t sure she could tolerate further distance blur. There is only one multifocal toric disposable contact lens available on the market (CooperVision Proclear XR toric multifocal), but there are no monthly disposable silicone hydrogel options with both an astigmatic and presbyopic correction at the same time.

Presenting the Options

Given IM’s desire to remain in EW, and her difficulty handling soft contact lenses, I discussed the option of gas permeable (GP) contact lenses. GP lenses have the benefit of better visual optics, more oxygen permeability, more deposit resistance and better handling. They come with a much reduced risk profile in terms of adverse events, and are safer for extended wear compared to soft contact lenses.1

I recommended Menifocal Z contact lenses with a goal for the lenses to be worn on a CW up to 30 days. This concentric bifocal GP contact lens, with a centre distance optical zone transitioning to the near optical zone in the periphery (refer fig 3), is made of a hyper-Dk lens material with a Dk of 164 approved for up to 30 days of CW. It is available in 7.10 to 8.50 in 0.10 steps, with diameters of 9.6 or 9.8. The power range is +5.00DS to -13.00DS and near additions are available in +1.00, +1.50, +2.00 and +2.50. The lens has been shown clinically to function very well for vision at distance and near, with excellent comfort and low adverse reactions.2

After two weeks with no extended wear and twice daily Patanol to reduce the allergic conjunctivitis, IM was prescribed Menifocal Z contact lenses with the parameters R 8.4/9.6/+4.75, +2.00 near add; L 8.4/9.6/+3.75, +1.50 near add.

At delivery, she achieved contact lens acuity of R 6/9, L 6/6+ and N5 at near. The lens exhibited a well fitting fluorescein pattern with alignment fit, good edge clearance, and stable centration achieved by lid attachment (refer figure 2).

IM was taught to insert and remove the lens, advised of the adaptation period and reviewed the next morning. Upon review, there were no signs of any adverse events.

At her one-week review, IM was rapt with the vision. She found she was no longer squinting to see, and noted a marked improvement in distance and near vision. She could wear the lenses comfortably with few problems, except for the occasional foreign particle beneath the lens. She was also more confident in inserting and removing these lenses compared to soft contact lenses.

No Need for Compromise

Renowned optometrist, author and academic Professor Nathan Efron AC predicted the demise of GP contact lenses by 2010, and although they are still going strong in 2015, they are rarely first choice for most patients. Soft contact lens technology has become the preferred option, requiring less time and financial investment by the patient. However, there are patients that don’t sit exactly within the fitting parameters already out there, and these patients should not have to compromise.

I never decide for a patient whether they are motivated or not to try an alternative lens option. I offer them the options and let them tell me. Even if they choose not to proceed or if they are unsuccessful, they appreciate that I have given them the options, and they value my expertise and experience.

Jessica Chi is the director of Eyetech Optometrists, an independent speciality contact lens practice in Melbourne. She is the current Victorian and National President of the Cornea and Contact Lens Society, and an invited speaker at meetings throughout Australia and beyond. She is a clinical supervisor at the University of Melbourne, and has served on the continuing education committee for the Australian College of Optometry and the Therapeutics Advisory Board for the Optometry Association of Australia.

References

1. Stapleton F, Kaey L, Edwards K, et al. The incidence of contact lens-related microbial keratitis in Australia. Ophthalmology 2008; 115:1655-62

2. Lakkis, C., Goldenberg, S.A. and Woods, C.A. 2005, Clinical performance of the Menifocal Z bifocal contact lens during 30 day continuous wear, in BCLA 2005

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