Ophthalmic and Physiological Optics最新文献

Purpose: To provide a more sophisticated explanation of the optics involved when retinal 'shadows' are seen in scanning laser ophthalmoscopic images during the wear of multisegment and diffusion optic spectacle lenses.

Methods: Images were recorded with a system that uses a scanning broad line fundus imaging principle in participants with undilated pupils wearing a multisegment spectacle lens. The live infra-red preview display of the system was also acquired during image recording. Ray-tracing and image simulations were performed, assuming a Maxwellian illumination system in which a source was refracted first through a lens and then through a model of a multisegment spectacle lens focused onto the pupil of an eye model and hence to the retina. A detector surface was positioned slightly in front of the retina to record the irradiation distribution. The light source was varied from 0.1 μm to 1.8 mm in diameter to investigate the effect of light source size on retinal irradiation distribution.

Results: The retinal shadow pattern was visible on the live infra-red preview display, as reported previously. However, the recorded images of the retina do not exhibit the same shadow pattern. The simulations predict that the circular shadows corresponding to lenslet positions become progressively less discernible with increasing light source size.

Conclusion: An explanation is provided for the shadows on retinal images due to multisegment lenses, which may be observable under certain illumination conditions.

Purpose: To investigate the methods of subjective refraction and prescribing used by UK optometrists in routine eye examinations.

Methods: Following a pilot study of 12 observed refractions conducted by nine optometrists, a questionnaire consisting of simple questions regarding methods used together with conditional response clinical vignettes was constructed. Paper copies were distributed to UK optometrists attending continuing professional development (CPD) courses, in addition to an online version.

Results: Two hundred and four completed questionnaires were gathered from respondents with a mean experience of 16 years (SD, 12 years). Poor technique was defined as likely to contribute to or cause a recheck according to a previous study. Poor techniques seen included visual acuity (VA) not being measured to a full threshold level by 93% of respondents, 37% (55/149) prescribing a small oblique cylinder to an asymptomatic patient and 39% (71/183) making just one subjective change to the axis of a -1.00 D cylinder from their starting prescription before prescribing that axis change to a mildly symptomatic patient. The risk of over-plusing was identified, with 28% (N = 46) of respondents happy to prescribe a full objective +0.50 DS change to a patient with no distance-related symptoms. Symptoms, prescription change and VAs are often not reconciled, with 43% (82/189) of respondents reporting being happy to prescribe a full subjective change of -2.00 DS together with -0.75 DC for a 72-year-old patient for a relatively small VA improvement of 6/15 to 6/7.5.

Conclusions: Poor subjective refraction and prescribing techniques were identified; limited measurement of VA to full threshold, risk of over-plusing/under-minusing, limited cylinder power and axis techniques and symptoms often not reconciling with changes in prescription and improvements in VA were observed. The objective prescription, particularly as determined by autorefractors, holds an exaggerated influence over some optometrists. These are elements of everyday optometry, yet require greater emphasis in CPD.

Purpose: The chronic capacity crisis in secondary care glaucoma services has resulted in calls to expand contributions by primary care optometrists. This study aims to map the current geographic spread of optometrists with post-graduate higher qualifications in glaucoma and independent prescribing (IP) within the UK, providing insight into the potential for expansion of capacity in glaucoma care.

Methods: Data on glaucoma-related and IP higher qualifications accredited by the College of Optometrists, as of April and August 2024, respectively, were analysed. The geographic distribution was mapped at both regional and local district levels using Quantum Geographic Information System software, geolocation application programming interface (postcodes.io) and programming languages JavaScript and Structured Query Language. Results for 2024 were compared with those previously published to determine change over time.

Results: From 2021 to 2024, the number of optometrists with higher qualifications in glaucoma has increased: Professional Certificate holders rose by 48% to 1986, Higher Certificate holders by 29% to 223, Diploma holders by 49% to 145, those with both Diploma and IP qualifications by 57% to 127 and IP alone holders by 88% to 1952. Regional variations appear to persist.

Conclusion: The number of optometrists holding postgraduate higher qualifications in glaucoma and IP in the UK has increased substantially. These data suggest that primary care optometrists are willing to upskill to gain the necessary glaucoma accreditations required to provide glaucoma care, potentially affording significant primary care capacity expansion to existing glaucoma services.

Aims: To evaluate the efficacy of CARE spectacle lenses in slowing myopia progression among European children.

Methods: In a 2-year randomised, parallel-group, double-masked, multicentre clinical trial, 234 European children aged 6-13 years were enrolled. All participants were myopic, with a cycloplegic spherical equivalent refractive error (SE) between -0.75 D and -5.00 D, astigmatism ≤1.50 D, anisometropia ≤1.00 D and myopia progression of at least 0.50 D in the previous year. The treatment group received MyoCare spectacle lenses with cylinder annular refractive elements (CARE), the control group single-vision lenses (SVL). Axial length (AL) and SE were measured at baseline, 6 and 12 months. Wearability questionnaires were administered at 1 week and 3 months. Central and peripheral visual acuity (VA) was recorded at dispensing and after 3 months. Generalised linear models estimated changes in SE and AL, adjusting for lens type, age and baseline measurements.

Results: After 12 months, children wearing CARE lenses showed less myopia progression, with a difference in SE and AL progression (compared to SVL) of -0.21 D (CI: 0.10 to 0.32 D) and 0.14 mm (CI: -0.17 to -0.10 mm), respectively. Central VA did not decrease with CARE lenses. Peripheral VA decreased by 0.10 and 0.09 logMAR in the nasal and temporal zones, respectively. Analysis of fast progressors indicated that 39.7% of SVL wearing eyes progressed by ≤-0.50 D/year compared to 21.1% with CARE (p < 0.01). For AL, 56.0% of SVL children had an elongation ≥0.20 mm compared to 21.3% with CARE (p < 0.01).

Conclusions: In European children, myopia progression was significantly slower with CARE lenses compared with SVL after 1 year of lens wear. Further monitoring will provide a comprehensive evaluation of long-term efficacy.

Purpose: To investigate the influence of light modulation conferred by current designs of myopia control spectacles on retinal sensitivity.

Methods: Retinal sensitivity and scanning laser ophthalmoscopy (SLO) fundus images were obtained from nine healthy subjects using a Macular Integrity Assessment microperimeter with current myopia control spectacle lenses: MyoCare, Stellest, MiYOSMART and DOT. Respectively powered single vision lenses and a 0.8-grade Bangerter occlusion foil (BF) served as comparative controls.

Results: Using the SLO image, one can visualise the areas of light modulation of the various myopia control lens designs at the level of the retina. Clear zone sizes differ between lens designs, with the DOT lens having the smallest area. Retinal sensitivity in areas of local light modulation was not reduced for the Stellest and MyoCare lenses, but declined with the MiYOSMART lens, suggesting a more prominent local light modulation. The DOT lenses produced a significant reduction in overall retinal sensitivity, although the reduction with the BF was greater. In all instances, retinal sensitivity remained well above the range considered normal for a healthy retina.

Conclusions: None of the lenses tested produced a clinically relevant reduction in retinal sensitivity and all scored significantly better than the lowest (that is, 0.8) grade BF. Given that current myopia control spectacles do not show consistent treatment effects as required to slow progression effectively over extended periods, there appears to be a subtle, yet crucial difference in spatial light modulation among these myopia control spectacle lenses. Seemingly similar lens designs cannot be assumed to have equivalent treatment effects; a thorough assessment of these nuances is essential to ensure accurate claims regarding their long-term efficacy.