La présence du système endocannabinoïde (eCB), en particulier le récepteur CB1 (CB1R), dans la rétine, le corps genouillé latéral, et l’aire visuelle primaire (V1) du singe a récemment été mise en évidence. Cependant, aucune étude n’a démontré la présence de ce système dans l’aire visuelle secondaire V2, une région qui reçoit la plupart des efférences de V1. Comme V1 exprime ce récepteur, nous faisons l’hypothèse que l’aire V2 l’exprime également. Le but de notre étude est donc de caractériser l’expression et la localisation cellulaire de ce système dans l’aire V2 du singe vervet. Des cerveaux de cinq singes vervets (Chlorocebus sabeus) adultes ont été utilisés. Les marqueurs cellulaires NeuN, SMI-32, et PV ont été employés pour caractériser et identifier les différentes couches de V2. En localisant ces derniers, nous déterminons la distribution de CB1R et des enzymes de synthèse (NAPE-PLD) et de dégradation (FAAH) du système eCB en utilisant des techniques d’immunofluorescence. De plus, l’organisation laminaire en six couches de V2 a été mise en évidence par nos marqueurs cellulaires. Nos résultats démontrent la présence de CB1R dans les fibres axonales aux extrémités de V2, c’est-à-dire dans les couches superficielles (1-3) et profondes (5-6). CB1R est peu ou pas exprimé dans la couche 4. CB1R entoure, mais n’est pas exprimé par les cellules positives- NeuN, SMI-32 et PV. Cependant, les enzymes NAPE-PLD et FAAH sont présentes dans les cellules pyramidales SMI-32 et les cellules interneurones PV -positives. Ces données indiquent que CB1R, NAPE-PLD et FAAH sont présentes dans V2 et pourraient moduler l’information visuelle provenant de V1 et se dirigeant vers les aires V4 et V5, et probablement, influencer la perception visuelle. / The presence of the endocannabinoid system in the retina, the lateral geniculate body, and the primary visual area (V1) of the monkey has recently been established. However, no study has demonstrated the presence of this system in area V2, a region that receives most of the afferents from V1. As V1 expresses this system, we assume that the area V2 also expresses it. The aim of our study is to characterize the expression and cellular localization of this system in the visual cortex V2 of the vervet monkey. The brains of 5 adult monkeys were used in this project. Cellular markers NeuN, SMI-32, and PV were used to characterize and identify the layers of V2. Using immunofluorescence, these markers were also localized in order to study the distribution of CB1R, the enzyme of synthesis (NAPE-PLD) and of degradation (FAAH) of eCB ligands. The six-layer organization of V2 was also identified by our cellular markers. Our results show the presence of the eCB system in area V2. Furthermore, we found that CB1R immunoreactivity is present in the axonal fibers at the ends of V2; in the superficial (L1-3) and deep (L5-6) layers. CB1R expression was low to non-existence in layer 4. CB1R surrounds but does not co-localize with NeuN-, SMI-32-, and PV- positive cells. On the other hand, NAPE-PLD and FAAH enzymes were co-localized with SMI-32-positive pyramidal cells and PV-positive interneuron cells. These data, therefore, indicate that CB1R, NAPE-PLD and FAAH are present in V2 and their presence can modulate visual information coming from V1 and going to V4 and V5, and probably, influence visual perception.

Yes / Although urgent primary eye care schemes exist in some areas of England, their current safety is unknown. Accordingly, the aim of the present study was to quantify the clinical safety and effectiveness of a COVID-19 Urgent Eyecare Service (CUES) across Luton, Bedford, Hull, East Riding of Yorkshire and Harrogate. Consenting patients with acute onset eye problems who had accessed the service were contacted to ascertain what the optometrist's recommendation was, whether this worked, if they had to present elsewhere and how satisfied they were with the CUES. A total of 27% (170/629) and 6.3% (28/445) of patients managed virtually and in person, respectively, did not have their acute eye problem resolved. Regression analysis revealed that patients who attended a face-to-face consultation were 4.66 times more likely to be correctly managed [Exp (β) = 5.66], relative to those solely managed virtually. Optometrists' phone consultations failed to detect conditions such as stroke, intracranial hypertension, suspected space occupying lesions, orbital cellulitis, scleritis, corneal ulcer, wet macular degeneration, uveitis with macular oedema and retinal detachment. Of referrals to hospital ophthalmology departments, in total, 19% were false-positives. Patients, however, were typically very satisfied with the service. Uptake was associated with socioeconomic status. The present study found that a virtual assessment service providing optometrist tele-consultations was not effective at resolving patients' acute-onset eye problems. The range and number of pathologies missed by tele-consultations suggests that the service model in the present study was detrimental to patient safety. To improve this, optometrists should follow evidence based guidance when attempting to manage patients virtually, or in person. For example, patients presenting with acute-onset symptoms of flashing lights and/or floaters require an urgent dilated fundus examination. Robust data collection on service safety is required on an ongoing basis.

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Yes / Purpose: To identify a minimum list of metrics of international relevance to public health, research and service development which can be extracted from practice management systems and electronic patient records in primary optometric practice. Methods: A two stage modified Delphi technique was used. Stage 1 categorised metrics that may be recorded as being part of a primary eye examination by their importance to research using the results from a previous survey of 40 vision science and public health academics. Delphi stage 2 then gauged the opinion of a panel of 7 vision science academics and achieved consensus on contentious metrics and methods of grading/classification. Results: A consensus regarding inclusion and response categories was achieved for nearly all metrics. A recommendation was made of 53 metrics which would be appropriate in a minimum data set. Conclusions: This minimum data set should be easily integrated into clinical practice yet allow vital data to be collected internationally from primary care optometry. It should not be mistaken for a clinical guideline and should not add workload to the optometrist. A pilot study incorporating an additional Delphi stage prior to implementation is advisable to refine some response categories. / This work was supported by the College of Optometrists.

Yes / Purpose: Although urgent primary eye care schemes exist in some areas of England, their current safety is unknown. Accordingly, the aim of the present study was to quantify the clinical safety and effectiveness of a COVID-19 Urgent Eyecare Service (CUES) across Luton, Bedford, Hull, East Riding of Yorkshire and Harrogate. Methods: Consenting patients with acute onset eye problems who had accessed the service were contacted to ascertain what the optometrist’s recommendation was, whether this worked, if they had to present elsewhere and how satisfied they were with the CUES. Results: 27% (170/629) and 6.3% (28/445) of patients managed virtually and in person, respectively, did not have their acute eye problem resolved. Regression analysis revealed that patients who attended a face-to-face consultation were 4.66 times more likely to be correctly managed (Exp (β) = 5.66), relative to those managed solely virtually. Optometrists phone consultations failed to detect conditions such as stroke, intracranial hypertension, suspected space occupying lesions, orbital cellulitis, scleritis, corneal ulcer, wet macular degeneration, uveitis with macular oedema and retinal detachment. Of referrals to hospital ophthalmology departments, in total, 19% were false-positives. Patients, however, were typically very satisfied with the service. Uptake was associated with socio-economic status. Conclusion: The present study found that a virtual assessment service providing optometrist teleconsultations was not effective at resolving patient’s acute-onset eye problems. The range and number of pathologies missed by teleconsultations suggests that the service model in the present study was detrimental to patient safety. To improve this, optometrists should follow evidence based guidance when attempting to manage patients virtually, or in person. For example, patients presenting with acute-onset symptoms of flashing lights and/or floaters require an urgent dilated fundus examination. Robust data collection on service safety is required on an ongoing basis. / The full-text of this article will be released for public view at the end of the publisher embargo on 10 Nov 2022.

Yes / Background: There are a number of limitations to the present primary eye care system in the UK. Patients with minor eye conditions typically either have to present to their local hospital or GP, or face a charge when visiting eye care professionals (optometrists). Some areas of the UK have commissioned enhanced community services to alleviate this problem; however, many areas have not. The present study is a needs assessment of three areas (Leeds, Airedale and Bradford) without a Minor Eye Conditions Service (MECS), with the aim of determining whether such a service is clinically or economically viable. Method: A pro forma was developed for optometrists and practice staff to complete when a patient presented whose reason for attending was due to symptoms indicative of a problem that could not be optically corrected. This form captured the reason for visit, whether the patient was seen, the consultation funding, the outcome and where the patient would have presented to if the optometrists could not have seen them. Optometrists were invited to participate via Local Optical Committees. Results were submitted via a Google form or a Microsoft Excel document and were analysed in Microsoft Excel. Results: Seventy-five percent of patients were managed in optometric practice. Nine and 16% of patients required subsequent referral to their General Practitioner or hospital ophthalmology department, respectively. Should they not have been seen, 34% of patients would have presented to accident and emergency departments and 59% to their general practitioner. 53% of patients paid privately for the optometrist appointment, 28% of patients received a free examination either through use of General Ophthalmic Service sight tests (9%) or optometrist good will (19%) and 19% of patients did not receive a consultation and were redirected to other providers (e.g. pharmacy, accident and emergency or General Practitioner). 88% of patients were satisfied with the level of service. Cost-analyses revealed a theoretical cost saving of £3198 to the NHS across our sample for the study period, indicating cost effectiveness. Conclusions: This assessment demonstrates that a minor eye condition service in the local areas would be economically and clinically viable and well received by patients.

Although experiential prescribing maxims are quoted in some optometric textbooks their content varies significantly and no direct research evidence was available to support their use. Accordingly in chapters 2 and 3, the uses of several potential prescribing rules were investigated in the UK optometric profession. Our results indicated that the subjective refraction result exerted a strong hold on the prescribing outcome with 40-85% of optometrists prescribing the subjective result in a variety of scenarios. The finding that after 40 years qualified, experienced optometrists were three times more likely to suggest a partial prescription was an important discovery that provides significant support for the prescribing rules suggested by various authors. It would also appear from the results of the retrospective evaluation of the ¿if it ain¿t broke, don¿t fix it¿ clinical maxim in Chapter 4 that spectacle dissatisfaction rates could be reduced by between 22 to 42% depending on how strictly the maxim is interpreted by the practitioner. Certainly an ¿if it ain¿t broke, don¿t fix it much¿ maxim was suggested as being particularly appropriate. Chapter 5 included a reanalysis of previously published data that found no change in falls rate after cataract surgery to investigate any influence of refractive correction change and /or visual acuity change on falls rate. Unfortunately these data were not sufficiently powered to provide significant results. In chapter 6, a spectacle adaptation questionnaire (SAQ) was developed and validated using Rasch analysis. Initial studies found no differences in SAQ with gender or age. / College of Optometrists

Accommodation is the change in the dioptric power of the eye altering the focus from distance to near. Presbyopia is the loss of accommodative function that occurs with age. There are many techniques used to measure accommodation, however, there is little consensus as to how clinical data should be collected and analysed. The overarching theme of this thesis is the in vivo examination of accommodation and how lifestyle can affect the onset of presbyopia. An open-field autorefractor with badal adaption was used to examine accommodative dynamic profiles under varying demands of vergence. From this data a new metric for assessing the time for accommodative change was derived. Furthermore this thesis describes a bespoke automated accommodative facility instrument that was developed to provide further assessment of accommodative speeds. Defocus curves are used for assessing accommodation and depth-of-focus; the work presented explores the use of non-linear regression models to define the most appropriate method of assessing defocus curves in phakic subjects, and pseudophakic subjects implanted with an extended depth-of-focus intraocular lens. Using an absolute cut-off criteria of +0.30logMAR improved the repeatability and reliability of the depth-of-focus metrics over a cut-off criteria relative to the best corrected visual acuity. A swept-source anterior segment optical coherence tomographer (AS-OCT) was used to image the morphology of the ciliary muscle during accommodation. The accuracy of ciliary muscle measurements was improved when using reference points on the sclera to align the AS-OCT scan. The use of a ciliary muscle area metric demonstrated poor repeatability and reliability when compared to the traditional assessment of muscle morphology via thickness measurements. Physiological ageing in the crystalline lens occurs in line with ageing in other structures in the body. The methods for assessing accommodative function examined in previous chapters, were used to examine whether lifestyle factors which affect the rate of systemic ageing, such as smoking, also affect accommodative function. Although being a current smoker and having greater central adiposity was associated with a slower time for accommodative change, further research is required before these findings can be applied to the target population.