Multifocal contact lenses can be broadly defined as contact lenses that correct more than one focal distance. They were launched initially in the late 1970s for patients who had presbyopia. More recently, however, multifocal contact lenses have been used increasingly for myopia management (Chamberlain et al, 2019; Walline et al, 2020). Today, many multifocal lens brands and designs are available (Remón et al, 2020), with most soft multifocal designs providing simultaneous vision (i.e., they correct both distance and near vision at the same time).
The quality and design of contact lenses have been continually improved to enhance the patient experience. Nonetheless, challenges with visual performance while using multifocal lenses have been a common cause of dropout (Sulley et al, 2018). Multifocal wearers have the highest rate of dropout compared to single-vision and toric lens wearers among new wearers (Sulley et al, 2018). Some common issues with multifocals are difficulty driving at night, halos, decreased vision, and decreased contrast sensitivity (Papas et al, 2009).
There are various questionnaires to specifically assess visual function for low vision (Mangione et al, 2001), post-laser-assisted in situ keratomileusis (LASIK) (Hays et al, 2017), refractive error corrections (Vitale et al, 2000), and multifocal intraocular lenses (IOLs) (Lévy et al, 2010). However, we lack one visual performance questionnaire that can be used to compare different multifocal lenses for a patient. Many studies focus on quantifying different visual outcomes such as visual acuity, contrast sensitivity, and stereopsis (Fernandes et al, 2013; Sha et al, 2016). But, there is little information on the qualitative experiences of visual comfort. Due to the lack of an established questionnaire in this area, it is challenging for practitioners to assess patients’ visual comfort. This article summarizes the available questionnaires for evaluating multifocal contact lens visual comfort. It then identifies the challenges associated with these generalized questionnaires, and it provides some suggestions to help with multifocal lens success.
Visual Performance Questionnaires
Contact Lens Impact on Quality of Life (CLIQ) Questionnaire (Pesudovs et al, 2006) CLIQ is a 28-item Rasch-validated questionnaire. It provides a relatively simple method to calculate the raw final score, which is then translated into person measures with Rasch analysis. CLIQ was developed to evaluate the quality of life among all types of contact lens wearers. The questionnaire was tested predominantly in a population of soft disposable lens wearers with ages ranging from 16 to 34 years (pre-presbyopia).
Orthokeratology and Contact Lens Quality of Life Questionnaire (OCL-QoL) (McAlinden and Lipson, 2018) OCL-QoL is a 23-item, Rasch-validated questionnaire that was developed primarily for orthokeratology lens wearers. Because it would not be valid to use this questionnaire before and after fitting orthokeratology lenses exclusively, the authors included other lens modalities. Hence, you can compare the outcomes of other contact lenses against orthokeratology. The OCL-QoL’s validation study did not include multifocal lenses.
Near Activity Visual Questionnaire (NAVQ) (Buckhurst et al, 2012) NAVQ is a 10-item, Rasch-validated questionnaire. It was developed to evaluate near visual function for different near vision corrections such as monofocal IOLs, accommodating IOLs, multifocal IOLs, varifocal spectacles, and multifocal contact lenses. NAVQ was tested predominantly in presbyopic subjects.
National Eye Institute – Refractive Error Quality of Life (NEI-RQL) (Hayes et al, 2003) The NEI-RQL is a 42-item questionnaire that has been validated to compare different types of refractive correction. When evaluated with Rasch analysis, it was deficient in all of the psychometric properties considered (McAlinden et al, 2011). Nevertheless, the NEI-RQL has been used to compare refractive error corrections including orthokeratology and soft contact lenses (Queirós et al, 2012).
Quality of Vision (QoV) (McAlinden et al, 2010) QoV is a 30-item, Rasch-validated questionnaire. It provides three separate scales, with scores for frequency, severity, and bothersomeness of symptoms. The symptoms include glare, halos, starbursts, hazy vision, blurred vision, distortion, double vision, fluctuation, focusing difficulties, and depth perception. The QoV questionnaire is suitable for patients who do and do not use vision correction (spectacles, contact lenses, refractive surgery, IOLs). Kang et al (2017) used the QoV to assess multifocal contact lenses worn for myopia management.
Other Questionnaires (Fedtke et al, 2016; Kollbaum et al, 2013; Sha et al, 2016; Sha et al, 2018) Some study authors have created their own questionnaires to evaluate multifocal contact lenses. These questionnaires typically include items related to common patient complaints. Most do not have any associated scoring system and are often used in conjunction with objective vision assessments. Kollbaum et al (2013) used a verbal numerical scale rating system (0 to 100). All other mentioned studies used a Likert scale to evaluate patient opinions.
All of the above questionnaires contribute to evaluating the visual performance of multifocal contact lenses to varying degrees. The inconsistency among studies regarding the questionnaire used makes it impossible to compare results from one study to another. Unfortunately, none of the studies compared the visual comfort across different multifocal lens designs or brands. This subsequently necessitates practitioners to use trial and error to determine a suitable lens for a patient. This issue, along with the likely associated contact lens dropout, could be mitigated by a standardized questionnaire aimed explicitly at evaluating multifocal lens visual performance.
Visual Performance Challenges
Inherent patient differences combined with the availability of multiple multifocal lens designs make it challenging to obtain an initial ideal fit. Also, some patients have expectations that may never be met with soft multifocals. The current literature regarding contact lens discomfort is strongly focused on lens material, environmental factors, and the ocular surface. There is limited data related to the impact of different multifocal lens designs on visual comfort. Hence, additional studies in this area are warranted.
Because multifocal contact lenses are used both for myopia management in children and for presbyopic adults, the assessment metrics should evaluate the full spectrum of characteristics of all potential wearers. To overcome these challenges, the community must work in unison to identify the effects of different multifocal designs and the full spectrum of patients’ visual needs. These data can then be used to establish a standardized questionnaire that can easily be employed in office.
It has been well established that the visual performance of multifocal contact lenses differs compared to that of single-vision contact lenses (Kollbaum et al, 2013). Current research suggests a few key points of difference between the two designs. Specifically, counsel patients from the start that multifocal lenses can have a longer adaptation time compared to single-vision lenses. Patients should likewise be made aware that low-contrast visual acuity may be affected by multifocal lenses more than by single-vision lenses (Gregory et al, 2021; Kang et al, 2017). Patients should be made aware that reading speed may also be affected by multifocal lenses; for patients who are sensitive to the reduced reading speed, other forms of correction such as spectacles may need to be considered during heavy reading sessions (Gregory et al, 2021). It is important to consider lens centration during the fitting process; decentration could alter the available viewing zones, which in turn may induce aberrations and affect vision (Fedtke et al, 2016). If any of these issues are noticed, it may be best to switch lens brands (Pucker and Tichenor, 2020). Furthermore, whenever possible, it is best to first prescribe multifocal lenses during early presbyopia, because this practice may allow for easier patient adaptation (Fedtke et al, 2016).
The literature overall indicates a significant loss of multifocal lens wearers due to visual discomfort (Sulley et al, 2018). While several well-established designs are available, new innovations and better diagnostic instruments are likely needed to dramatically improve the success of multifocal lens wearers. Other challenges such as fitting both children and presbyopic adults who have different pupils sizes and comprehension levels may make it even more difficult to develop multifocal designs and standard assessment tools. These problems will hopefully all be solved by a collaborative effort between eyecare practitioners and contact lens industry partners. CLS
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