Ophthalmic and Physiological Optics最新文献

Purpose: Smartphones are the most frequently used digital devices globally with ~6.80 billion users. Despite the ubiquitous use of smartphones, limited information is known on the preferred viewing distance and font size of smartphone users. This study investigated viewing distance, font size and symptoms of eyestrain in non-presbyopic and presbyopic smartphone users.

Methods: In this quantitative research study, viewing distance and font size were measured in a group of non-presbyopes (n = 107) and presbyopes (n = 53), whilst participants viewed a text message and a web page on their own smartphone. Subjects also responded to a verbal questionnaire related to the characteristics of their smartphone and the computer vision syndrome questionnaire to assess symptoms of eyestrain. Data were analysed using descriptive and inferential statistics.

Results: For the total sample, the mean viewing distance for a text message was 37.13 ± 8.82 cm (median 36.00 cm), and for a web page was 36.11 ± 7.98 cm (median 36.00 cm). Presbyopes had longer median viewing distances compared with non-presbyopes for a text message (41 cm vs. 34 cm, p < 0.001) and web page (40 cm vs. 34 cm, p < 0.001). The font size for non-presbyopes were <1.0 M whilst for presbyopes were >1.2 M. More than twice the percentage of non-presbyopes were classified with digital eyestrain (DES) compared with presbyopes.

Conclusions: Non-presbyopes used shorter viewing distances, smaller font sizes and were more predisposed to DES than presbyopes. The viewing distances adopted by presbyopes were similar to the conventional near-working distance of 40 cm. Eye care practitioners should consider viewing distances when assessing near-visual functions and prescribing a near refractive correction, particularly in non-presbyopes. There should be greater awareness of the importance of adopting appropriate viewing distances when using smartphones.

Aim: To develop an accommodating, wide-angle, schematic eye for emmetropia and myopia in which spectacle refraction and accommodation level are input parameters.

Method: The schematic eye is based on an earlier unaccommodated refraction-dependent eye for myopia developed by Atchison in 2006. This has a parabolic gradient index lens and parameters derived from biometric and optical measurements on young adults. Several parameters are linearly dependent upon spectacle refraction (anterior radius of curvature of the cornea, axial length and vertex radii of curvature and conic asphericities of a biconic retina). The new accommodated schematic eye incorporates accommodation-dependent changes in several lens-related parameters. These changes are based on literature values for anterior chamber depth, lens thickness, vitreous chamber depth, lens surface radii of curvature and lens front surface asphericity. A parabolic variation of refractive index with relative distance from the lens centre is retained, with the same edge and centre refractive indices as the earlier model, but the distribution has been manipulated to maintain focus near the retina for the emmetropic case at 0 and 4 D accommodation. The asphericity of the lens back surface is changed so that spherical aberration and peripheral refraction approximately match typical literature trends. The model is used to compare spherical aberration and peripheral refraction in eyes with up to 4 D of myopia and 4 D of accommodation.

Results: The levels of spherical aberration in the unaccommodated schematic eyes are similar to literature values for young adults, but the changes in spherical aberration with accommodation are approximately two-thirds of that found in an experimental study. As intended, peripheral refractions in the accommodated schematic eyes are similar to those of their unaccommodated counterparts.

Conclusion: The wide-angle model extends the range of schematic eyes to include both refraction and accommodation as variable input parameters. It may be useful in predicting aspects of retinal image quality.

Purpose: This study measured associations between ON and OFF functional indicators and structural optical coherence tomography (OCT) and OCT angiography (OCTA) markers in diabetic retinal disease.

Methods: Fifty-four participants with type 1 or type 2 diabetes (mean age = 34.1 years; range 18-60) and 48 age-matched controls (mean age = 35.4 years, range 18-59) underwent visual psychophysical testing, OCT and OCTA retinal imaging. Psychophysical tasks measuring (A) contrast increment and decrement sensitivity and (B) response times to increment and decrement targets were assessed as surrogate measures of ON and OFF retinal ganglion cell function.

Results: The group with diabetes had worse foveal contrast increment and decrement thresholds (p = 0.04) and were slower to search for increment and decrement targets relative to controls (p = 0.009). Individuals with diabetes had a less circular foveal avascular zone (FAZ) (p < 0.001) but did not differ from controls in foveal vessel density and FAZ area. Functional and structural outcome measures related to the peripheral retina were also comparable between those with and without diabetes. Functional responses to increments and decrements were not significantly correlated with FAZ circularity or vessel density in individuals with diabetes.

Conclusions: Diabetic retinal disease results in impaired performance on measures of inferred ON and OFF pathway function in addition to vascular deficits measurable with OCTA. Future longitudinal studies may determine the temporal relationship between these deficits, and whether they predict future diabetic retinopathy.

Purpose: To investigate the potential improvement in visual acuity and subjective perception of image quality in patients with keratoconus using non-orthogonal correction (NOC) cylinder trial lenses where the steep and flat power meridians are set at angles less or greater than 90°.

Methods: A set of NOC plano/cylindrical trial lenses, where the axes between the power meridians were set at a range of non-orthogonal angles, were used to refract 18 participants with keratoconus in whom 23 eyes were used for testing. Corneal elevation data were processed by bespoke MATLAB code from Pentacam Scheimpflug tomographer scans. Each participant first underwent subjective refraction using standard orthogonal cylinder trial lenses, and the monocular best-corrected visual acuity (BCVA, logMAR) was recorded for each eye. They then underwent a second subjective refraction using NOC cylinder trial lenses created for the study and completed a questionnaire to elicit their subjective appraisal of letter clarity and ghosting.

Results: Fourteen (61%) eyes demonstrated an increase in objective BCVA with the NOC versus the orthogonal correction; seven (30%) eyes showed no change and in two (9%) eyes, the BCVA was slightly worse. Further, 87% and 79% experienced an increase in letter clarity and a reduction in ghosting, respectively, independent of changes in BCVA. The majority of non-orthogonal angles were in the range of 80°-85°, and it was possible to refine the cylinder and axis of the NOC further compared with the orthogonal correction. All but one of the participants said they would be interested in trying non-orthogonal spectacles if the opportunity arose.

Conclusions: Correcting irregular astigmatism in keratoconic individuals with non-orthogonal spectacle correction may provide benefit in terms of increased visual acuity, improvements in letter clarity and a reduction of ghosting effects. This type of correction has the potential to improve the overall quality of life for patients with keratoconus.

Background: Active vision therapy for amblyopia shows good results, but there is no standard vision therapy protocol. This study compared the results of three treatments, two combining patching with active therapy and one with patching alone, in a sample of children with amblyopia.

Methods: Two protocols have been developed: (a) perceptual learning with a computer game designed to favour the medium-to-high spatial frequency-tuned achromatic mechanisms of parvocellular origin and (b) vision therapy with a specific protocol and 2-h patching. The third treatment group used patching only. Fifty-two amblyopic children (aged 4-12 years), were randomly assigned to three monocular treatment groups: 2-h patching (n = 18), monocular perceptual learning (n = 17) and 2-h patching plus vision therapy (n = 17). Visual outcomes were analysed after 3 months and compared with a control group (n = 36) of subjects with normal vision.

Results: Visual acuity (VA) and stereoacuity (STA) improved significantly after treatment for the three groups with the best results for patching plus vision therapy, followed by monocular perceptual learning, with patching only least effective. Change in the interocular difference in VA was significant for monocular perceptual learning, followed by patching. Differences in STA between groups were not significant. For VA and interocular differences, the final outcomes were influenced by the baseline VA and interocular difference, respectively, with greater improvements in subjects with poorer initial values.

Conclusions: Visual acuity and STA improved with the two most active treatments, that is, vision therapy followed by perceptual learning. Patching alone showed the worst outcome. These results suggest that vision therapy should include monocular accommodative exercises, ocular motility and central fixation exercises where the fovea is more active.

Purpose: To evaluate the value of enhanced optometric services for managing neovascular age-related macular degeneration (nAMD) and glaucoma in primary care optometry services, instead of hospital eye services (HES).

Methods: Seven enhanced optometric service pathways in primary care in Wales were assessed with a mixed-methods approach: three for nAMD and four for glaucoma. The methods were a patient-related experience measure (PREM), a Realist Review and Evaluation involving both patients and staff, a discrete event simulation model estimating the economic impact of the pathways and a workforce survey of optometrists to gauge capability and capacity.

Results: Patient-related experience measure responses (802) indicated that primary care experience was comparable to that of HES. Utilising enhanced optometric services in primary care resulted in reduced wait times compared with HES, with suspected nAMD shortened to 4-5 days and glaucoma monitoring to 5 days. Waiting lists were dramatically reduced with primary care-based services to just three people waiting for nAMD and five for glaucoma, compared with 216 and 5691 people, respectively, in HES. Consultant ophthalmologist time was reduced from 57% to 15%-16% for nAMD services and from 48% to 22%-23% for glaucoma services. Integrating enhanced optometric services into primary care incurred a similar cost. The workforce survey confirms that optometrists possess the skills and qualifications and are willing to deliver these enhanced optometric services. The Realist Review and Evaluation revealed that clear patient communication, effective coordination and strong interprofessional communication between optometrists and ophthalmologists along with a shared electronic record are crucial to the success of this change.

Conclusion: Providing enhanced optometric services in primary care for nAMD and glaucoma brings substantial benefits for the UK National Health Service and patients, including reduced waiting times, waiting lists and released HES capacity. The success of this transition hinges on clear patient communication, administrative co-ordination and effective interprofessional communication.

Purpose: Socioeconomic deprivation is associated with an increased incidence of sight-loss. To inform potential developments in eyecare, General Ophthalmic Service (GOS) sight-testing activity was explored in relation to deprivation for GOS contractors submitting National Health Service (NHS) claims in England.

Methods: Data on NHS sight-test claims for the financial year 2022-2023 were sought from NHS England (NHSE), including number of sight-tests by GOS contractors, their unique Organisation Data Service codes and postcodes and age-bands of patients accessing sight-testing. Deprivation scores were assigned to contractor practices using the Index of Multiple Deprivation (IMD) and the average number of sight-tests for all contractors within each IMD decile calculated, allowing rate of sight-testing per 1000 population per decile of deprivation to be estimated using Office of National Statistics (ONS) Lower Layer Super Output Area mid-year population estimates. Inequality was examined using the Odds Ratio (OR) and slope and relative index of inequality measures (SSI and RII).

Results: Overall, 12.94 million NHS sight-tests were provided by 5622 GOS contractors in England in 2022-2023. Most affluent decile GOS contractors undertook an average ~2200 NHS sight-tests, while in the most deprived decile, average NHS sight-tests per contractor was ~1100. Rate of sight-testing per 1000 population in the most deprived decile was one quarter of that in the most affluent, with an OR of 5.29 (95% CI 5.27-5.30), indicating those in the most affluent areas were ~five times more likely to access NHS sight-tests. Overall, SII and RII were 333.5 (95% CI 333.52-333.53) and 6.4 (95% CI 6.39-6.40), respectively, findings reflective of substantial inequality in uptake.

Conclusion: There remains substantial unwarranted variation in uptake of NHS sight-testing, with those in more affluent areas accessing sight-testing substantially more than those in more deprived areas. Strategies are required to facilitate primary care optometry to provide more equitable access to eyecare.

Purpose: When myopia control treatment is discontinued, progression will increase, but does it revert to expected values based on the age and race of the child or does it accelerate further? The latter scenario is considered a rebound.

Methods: A PubMed search was conducted with the words 'rebound' and 'myopia control', identifying further papers from reviews. Inclusion was limited to prospective studies with ≥6 months of treatment, ≥3 months of data following cessation and with axial length data, which allowed calculation of rebound. Nineteen studies were identified, comprising 24 treatment groups. In 10 studies, untreated control children were followed both throughout the treatment and cessation periods, allowing for a concurrent comparison group. In three studies, a control group was followed for 1 or 2 years and thereafter received the treatment under evaluation. Later, treatment ceased in the originally treated children. Finally, six studies were cross-over designs. For these latter two study designs, initial axial elongation and myopia progression in the control group were extrapolated to the cessation period, accounting for annual slowing. Values from durations of <1 year were annualised.

Results: The mean annualised rebound was +0.05 ± 0.10 mm and -0.09 ± 0.24 D for axial length and myopia progression, respectively, and these were correlated (r² = 0.59, p < 0.001). Rebound was associated with 1-year treatment efficacy (r² = 0.43, p < 0.001). The mean annualised rebound with optical corrections was -0.01 ± 0.03 mm. Five of the six highest rebound values (≥0.14 mm) were from red light therapy and atropine studies. Rebound ranged from +0.03 to +0.14 mm for overnight orthokeratology.

Conclusions: Consistent with previous statements, no evidence for rebound was found for myopia control spectacles and soft contact lenses. Future research should explore the influence of age and magnitude of treatment efficacy on rebound.

Purpose: To introduce a novel methodology for subjective refraction based on power vectors with a conventional phoropter.

Methods: A conventional phoropter was used to measure power vector components of refraction (M, J₀ and J₄₅) directly by using the sphere power (for M measurement) and the cylinder power combined with the Jackson cross-cylinders (for J₀ and J₄₅ measurements). Conventional subjective refraction was also performed, and this result was mathematically transformed into power vector notation for comparison purposes. Visual acuities with the conventional prescription and the quasi-vector-based prescription were compared.

Results: Refractive error from 40 healthy participants was measured by conventional and quasi-vector-based subjective refraction. No differences were found between methods for any of the power vector components of refraction (p > 0.21 in all cases). The visual acuity achieved with the prescriptions yielded similar values (p = 0.85).

Conclusions: Subjective refraction can be measured directly in power vector notation using a conventional phoropter without any additional adaptation and computation.