Spectacle non-tolerance in clinical practice - a systematic review with meta-analysis

How small changes to one eye's retinal image can transform the perceived shape of a very familiar object

Vision can provide useful cues about the geometric properties of an object, like its size, distance, pose, and shape. But how the brain merges these properties into a complete sensory representation of a three-dimensional object is poorly understood. To address this gap, we investigated a visual illusion in which humans misperceive the shape of an object due to a small change in one eye's retinal image. We first show that this illusion affects percepts of a highly familiar object under completely natural viewing conditions. Specifically, people perceived their own rectangular mobile phone to have a trapezoidal shape. We then investigate the perceptual underpinnings of this illusion by asking people to report both the perceived shape and pose of controlled stimuli. Our results suggest that the shape illusion results from distorted cues to object pose. In addition to yielding insights into object perception, this work informs our understanding of how the brain combines information from multiple visual cues in natural settings. The shape illusion can occur when people wear everyday prescription spectacles; thus, these findings also provide insight into the cue combination challenges that some spectacle wearers experience on a regular basis.

BCLA CLEAR Presbyopia: Management with contact lenses and spectacles

This paper seeks to outline the history, market situation, clinical management and product performance related to the correction of presbyopia with both contact lenses and spectacles. The history of the development of various optical forms of presbyopic correction are reviewed, and an overview is presented of the current market status of contact lenses and spectacles. Clinical considerations in the fitting and aftercare of presbyopic contact lens and spectacle lens wearers are presented, with general recommendations for best practice. Current options for contact lens correction of presbyopia include soft simultaneous, rigid translating and rigid simultaneous designs, in addition to monovision. Spectacle options include single vision lenses, bifocal lenses and a range of progressive addition lenses. The comparative performance of both contact lens and spectacle lens options is presented. With a significant proportion of the global population now being presbyopic, this overview is particularly timely and is designed to act as a guide for researchers, industry and eyecare practitioners alike.

Systematic Review of Myopia Progression after Cessation of Optical Interventions for Myopia Control

Despite high discontinuation rates for myopia optical interventions, limited attention has been given to the potential rebound effects post-discontinuation. This systematic review aims to assess the extent of the rebound effects following the cessation of common clinical optical myopia-control interventions in children. A comprehensive search of PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov was conducted from inception to October 2023. The rebound effects, defined as changes in the axial length or spherical equivalent during and after treatment cessation, were categorized into four levels. These studies encompassed 703 participants and spanned from 2019 to 2023, with durations of treatment and cessation ranging from 6 months to 3.5 years and from 2 weeks to 5 years, respectively. This review, encompassing 14 studies, revealed a predominant strong rebound effect in orthokeratology (8 studies), a weak rebound effect in multifocal soft contact lenses (4 studies), and a variable rebound effect in peripheral-plus spectacle lenses (2 studies). Notably, with the increasing cessation duration, the rebound effects diminished, potentially linked to the reversal of choroidal thickening and the disappearance of peripheral myopic defocus. In conclusion, a temporal trend of rebound effects exists in all three myopia optical interventions, possibly contributing to their myopia control mechanisms.

Quality of refractive error care in Pakistan: an unannounced standardised patient study

OBJECTIVE

Undercorrected refractive errors are the primary cause of vision impairment worldwide, including in Pakistan. However, limited data exist on the quality of refractive error care. Our study assessed the quality of refractive error care in Punjab, Pakistan by estimating the proportion of spectacles that were optimally prescribed.

METHODS AND ANALYSIS

In this cross-sectional study, 12 unannounced standardised patients (USPs) from Jhang, Khanewal and Sahiwal districts were recruited. USPs underwent baseline subjective refraction and were trained to attend optical services, observe consultations, request spectacles and obtain prescriptions. The spectacles received were compared with baseline refraction to determine quality. We also examined the associations between spectacle quality, service and patient characteristics.

RESULTS

Out of 276 attempted visits to 69 optical services, 241 pairs of spectacles were dispensed. A population size-weighted percentage of 42.7% (95% CI 36.4% to 49.3%) of spectacles were optimal quality, with the range varying from 13.8% in Jhang to 67.0% in Khanewal. Half the suboptimal quality spectacles had horizontal prism deviations outside of tolerance limits. Optimal spectacles were associated with performing focimetry (unadjusted OR=7.15, 95% CI (3.02 to 16.94), p<0.001) and good communication (OR=2.23, 95% CI (1.06 to 4.67), p=0.03). Hyperopic USPs were less likely to receive optimal spectacles (OR=0.01 95% CI (0.00 to 0.11), p<0.001).

CONCLUSION

The quality of refractive error care in Pakistan requires improvement, particularly in the Jhang district. Key areas for enhancing refractive error care in Pakistan include refining dispensing and refraction skills for hyperopic prescriptions, providing training on the risks of using previous spectacles, and emphasising the importance of effective communication skills.

Visual satisfaction with progressive addition lenses prescribed with novel foveal fixation axis measurements

Progressive addition lens (PAL) prescription is usually conducted using the pupillary centre as a reference, which in general does not coincide with the visual axis (kappa distance), and this difference could induce undesired prismatic effects in far and near vision distances and adaptation problems. This study aimed to assess the impact on subjects' visual satisfaction with PALs prescribed based on foveal fixation axis (FFA) measurements. Two different PALs (LifeStyle 3i, Hoya Lens Iberia) were randomly prescribed [one with a customized inset (the difference between the FFA measurements (Ergofocus®, Lentitech, Spain) at far and near distances and the second with a standard inset (2.5 mm)] to be used by 71 healthy presbyopic volunteers in a prospective double-masked crossover clinical study involving one month of use of each PAL. Patients were self-classified into four groups according to their previous experience with PALs: neophyte, PAL users, PAL drop-out, and uncomfortable PAL users. Visual function and overall satisfaction with each PAL were collected and compared. Ninety-seven percent (95% CI 93-100%) of participants successfully adapted to PALs prescribed with FFA without significant differences (P = 0.26) among the study groups (100% neophyte and uncomfortable PAL users (95% CI 100% in both groups), 89% (95% CI 67-100%) PAL users and 94% (95% CI 82-100%) PAL drop-out group). There were no statistically significant differences in visual function (P > 0.05) between customized and standard inset PALs. Customized and standard inset lenses showed similar satisfaction (P > 0.42) that increased significantly (P < 0.01 without any carry-over effect) after 30 days of wear. PALs prescribed with FFA measurements showed high visual satisfaction, suggesting that these measurements are suitable for prescribing PAL adaptation processes. Additional research is necessary to assess differences in PAL users' performance with different prescription methods and lens designs.

Beyond traditional subjective refraction

PURPOSE OF REVIEW

The evaluation of refractive error is probably the most important and common procedure in eye care. The gold standard method for evaluating refractive error is subjective refraction, a process that has not significantly changed in 200years. This article aims to review recent technologies and novel approaches attempting to improve this traditional procedure.

RECENT FINDINGS

From laboratory prototypes to commercial instruments, the proposed methods aim to perform reliable and fast subjective refractions, following different approaches: using motorized phoropters in combination with automatic algorithms or even self-refraction, hybridizing objective and subjective measurements within the same instruments, or using new visual tasks beyond letter identification of blur estimation to obtain the refractive error subjectively.

SUMMARY

The current trend in subjective refraction is to overcome the traditional manual blur reduction method, using automatic and self-refraction instruments, which can provide faster measurements with lower variability. Many of the technologies reported here are already in the market, and some have the potential of becoming the new standard in subjective refraction.

What are the causes of non‐tolerance to new spectacles and how can they be avoided?

Purpose

To investigate non‐tolerance cases from several UK practices to determine their likely causes and how they might have been avoided.

Methods

Patient complaint and refraction data were collected from non‐tolerance recheck examinations. For one practice, clinical data were also collected retrospectively to investigate the quality of the eye examinations.

Results

Data for 279 rechecks were gathered from 10 practices and a recheck frequency of 2.3% was found. The mean patient age was 60 (SD 16) years, with cylinder changes responsible for 38% of prescription‐related causes of rechecks, overplusing or underminusing 26%, and underplusing or overminusing just 11%. An assessment of 242 recheck corrections found that 40% were unsatisfactory (e.g., failed to address initial or recheck symptoms, N = 45) and retrospective analysis of 217 case records showed many limitations (e.g., 61% or 28% recorded no uncorrected or habitual visual acuity (VA) at either initial examination or recheck).

Conclusions

Given that overplus‐underminus was a much bigger proportion of prescription‐related cases than overminus‐underplus (26% vs. 11%), the refraction mantra of “maximum plus for maximum VA” should be balanced by increased teaching of the problems of overplusing and underminusing, and the use of prescribing guidelines. In addition, continuing professional development regarding the basics of the recheck examination, refraction, visual acuity and prism determination is needed. Changes of oblique cylinders should be carefully considered in older patients as this is a common cause of non‐tolerance. In addition, if the “if it ain't broke, don't fix it” and related maxims had been applied to all patients who were asymptomatic at the original examination, one third of all non‐tolerance cases could have been avoided. Finally, it would seem appropriate for practices to develop a system to deal better with non‐tolerance cases. Perhaps an experienced clinician should examine all patients with non‐tolerance and provide feedback to the original clinician.

Quality-of-life outcomes of long-term contact lens wear: A systematic review

PURPOSE

The aim of this review was to evaluate the evidence on quality-of-life outcomes of long-term contact lens wear.

METHODS

A search for original articles that used validated measures to evaluate patient-reported outcomes (PROs) in long-term (≥2 years) contact lens wearers was conducted in Medline Ovid, PubMed, Scopus, Web of Science, Cochrane, CINAHL, and PsycInfo databases. The information including PRO measure (name, type, content) and key quality-of-life outcomes findings were extracted.

RESULTS

Seven articles that used 4 PRO measures to evaluate quality of life outcomes of long-term contact lens wear met the inclusion criteria. The median (range) number of contact lens wearers in these studies was 116 (31-247). The studies were conducted in 4 countries: USA, Spain, China, and Russia. All studies were conducted in myopic populations. None of the studies provided information on psychometric properties, validity and reliability of the PRO measures used. Five studies were conducted in children of which 3 studies evaluated PROs of myopia control contact lens wear. The studies reported that contact lens wear, including myopia control lens wear, was an effective method of refractive correction in children and adults in the long term in PRO-perspective, and resulted in a better quality of life status than with glasses. However, long-term dry eye and discomfort related symptoms were reported.

CONCLUSION

Overall, contact lens use improved quality of life status in children and adults. More research is required to better understand the long-term quality-of-life outcomes of contact lens wear.

What are patients' beliefs about, and experiences of, adaptation to glasses and how does this affect their wearing habits?

PURPOSE

It is well known that some patients experience difficulties adapting to new glasses. However, little is known about what patients themselves understand of the adaptation process, and how this influences their attitudes and the decisions they make when adapting to a new pair of glasses. Nor is it understood whether these factors affect their wearing habits.

METHODS

We conducted four focus groups. Participants were 22 glasses wearers (mean ± SD age 43 ± 14 years, range 21-71 years) who reported they: (1) wore spectacle correction for distance vision (single vision, bifocal or progressive lenses); (2) had struggled to get used to a new pair of glasses and (3) sometimes chose not to wear their distance correction. Focus groups were audio recorded, transcribed verbatim and analysed thematically.

RESULTS

We identified three themes. Trust is about how participants' trust in their optometrist and themselves influences the likelihood of them adapting successfully to new glasses. Conflict describes how the advice patients have received about adapting to glasses can conflict with what they have experienced and how this conflict influences their expectations. Part of Me explores how participants' experiences and feelings about their glasses are important to adaptation and this includes physical, visual, emotional and behavioural aspects.

CONCLUSIONS

The traditional optometric perspective of adaptation to glasses is much narrower than that held by patients, and significantly underestimates the physical, behavioural and emotional adaptation that patients must go through in order to feel fully comfortable wearing their glasses. Patients should receive significantly more information about adaptation, including symptoms that may be experienced and why these happen, practical tips to aid adaptation, and when and how to raise concerns. Patients should also receive information about the day-to-day effects of blur adaptation to avoid them not wearing their glasses, including for vision-critical tasks such as driving.