The latest medical research on Optometry
The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about optometry gathered by our medical AI research bot.
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Request AccessRefractive development II: Modelling normal and myopic eye growth.
Ophthalmic and Physiological OpticsDuring refractive development, eye growth is controlled by a combination of genetically pre-programmed processes and retinal feedback to minimise the refractive error. This work presents a basic differential model of how this process may take place.
The description starts from two bi-exponential descriptions of the axial power Pax (or dioptric distance) and total refractive power Peye, the difference between which corresponds with the spherical refractive error S. This description is rewritten as an ordinary differential equation and supplemented by a retinal feedback function that combines retinal blur (closed loop) with a term describing excessive axial growth (open loop). This model is controlled by a total of 18 parameters that allow for a wide variety of developmental behaviours.
The proposed model reproduces refractive development growth curves found in the literature for both healthy and myopic eyes. An early onset of myopisation, a large growth term and a high minimum for the crystalline lens power all lead to higher degrees of myopia. Assigning more importance to the feedback than to the pre-programmed growth makes the model more sensitive to myopogenic influences. Applying refractive corrections to the model, undercorrection is found to produce more myopia. The model compensates for a low-powered imposed lens and can return to (near) emmetropia if that imposed lens is removed quickly thereafter. Finally, simulating the effect of a diffuser leads to high myopia.
Using a series of basic assumptions, the proposed model recreates many well-known experimental and clinical results about refractive development from the literature while placing them in a standardised context. This contributes to a broader understanding of the origins of refractive errors, and future versions may help in the development of solutions for myopia control.
Exploring cognitive overload in adults with visual impairment: The association between concentration and fatigue.
Optometry and Vision ScienceThis study contributes to understanding the cognitive overload as experienced by adults with VI and highlights the importance of the association of concentration problems, as a reflection of the cognitive burden and perceived fatigue. It is recommended to identify and address concentration difficulties through suitable awareness and treatment strategies to prevent and reduce severe fatigue in this population.
Individuals with VI need to use additional cognitive resources to compensate for their loss of vision. These cognitive demands include increased concentration, which may put an extra burden on energy levels. This study aimed to expand upon previous research on the concept of cognitive overload by exploring the relationship between concentration and fatigue severity in individuals with VI.
A cross-sectional study was conducted based on data from the eligibility screening of the E-nergEYEze trial (n = 213). Concentration problems were measured with the Checklist of Individual Strengths subscale Concentration, and fatigue severity was measured with the Checklist of Individual Strengths subscale Fatigue Severity. Linear regression analyses were performed to investigate the association between concentration problems and fatigue severity. Potential effect modifiers (i.e., sociodemographic and vision-related characteristics) were considered, and associations were corrected for confounding.
Concentration problems were directly and positively associated with fatigue severity (β = 0.47; R2 = 0.10; 95% confidence interval, 0.28 to 0.66; adjusted model: β = 0.52; R2 = 0.16; 95% confidence interval, 0.32 to 0.72). No relevant effect modifiers were identified. However, other factors that were not included in this study were involved in this association.
Spotlight on Amniotic Membrane Extract Eye Drops: A Review of the Literature.
Eye Contact LensTo review the literature focusing on the effectiveness of amniotic membrane extract eye drops (AMEDs) in the treatment of ocular surface diseases.
PubMed/MEDLINE, Scopus, and CENTRAL databases were searched until March 4, 2024. Overall, we identified 1,121 studies, 26 of which were selected for a full-text review. Twelve studies met the inclusion criteria and were analyzed for clinical improvements, time to resolution of corneal staining, adverse events, and preparation methods. Strength of clinical data was graded according to the Oxford Center for Evidence-Based Medicine.
Overall, AMED compounds were used in 296 eyes of 205 patients. Fifty-nine percent of eyes were treated for dry eye disease, 23% for an epithelial defect, and the rest (18%) for other corneal wound healing disorders. Three main types of eye drops preparation were described, that is, lyophilized, homogenized, and fresh AMED. Although the methods of outcome reporting were heterogeneous, all included studies showed various grades of improvement in both signs and symptoms. The overall incidence of ocular side effects was 2.3%.
Despite the suboptimal quality of evidence, overall, the available literature suggests that AMED is a valuable tool in the treatment of ocular surface disorders.
What intrinsic factors affect the central corneal thickness?
Ophthalmic and Physiological OpticsThe cornea is one of the tissues responsible for covering and protecting the inner structures of the eye. Central corneal thickness (CCT) is define...
Systemic and Ocular Associations of Keratoconus.
Expert Review of VaccinesKeratoconus (KC) is the most prevalent corneal ectasia in the world and its pathogenesis is influenced by both ocular and systemic factors. This review explores the multifaceted associations between keratoconus and systemic health conditions, ocular characteristics, and various other environmental/exogenous factors, aiming to illuminate how these relationships influence the pathophysiology of the disease.
This review will summarize the fundamental attributes of KC, review and discuss the systemic and ocular association of KC including molecular biomarkers, and provide an organized overview of the parallel alterations occurring within various biological pathways in KC.
Despite the substantial volume of research on keratoconus, the precise etiology of the disease remains elusive. Further studies are necessary to deepen our understanding of this intricate disorder and improve its management.
Intrastromal Corneal Ring Segments and Keratoconus Progression: A Case Series Study.
Eye Contact LensTo assess keratoconus (KC) progression following the implant of intrastromal corneal ring segments (ICRSs) in young patients.
Retrospective, longitudinal, observational, controlled nonrandomized case series study. Keratoconus patients aged 25 years or younger who underwent uneventful ICRS surgery and completed at least 3 years of follow-up were enrolled. Controls were of similar age and treatment-naive patients with KC. The following Pentacam imaging (Oculus, Wetzlar, Germany) data were analyzed: keratometric (maximum, in-flattest meridian, in-steepest meridian, and mean), aberrometric (higher-order aberrations and coma), pachymetric (thinnest corneal thickness), and elevation (maximum posterior elevation). The main outcome measure was KC progression.
The study sample comprised 20 eyes of 18 cases (age 20.20 ± 3.70 years, nine right eyes, 14 male patients) and 30 eyes of 24 controls (age 20.80 ± 3.20 years, 15 right eyes, 21 male patients). The mean follow-up duration was 4.90 ± 1.70 years (range 3-8 years) for cases and 4.50 ± 1.40 years (range 3-8 years) for controls. Four cases and two controls met criteria for KC progression.
Intrastromal corneal ring segments did not have significant impact on KC progression in the cohort.
Evaluation of the Microbiology of Removed Punctal Plugs and Intracanalicular Devices.
Eye Contact LensThe purpose of this observational study was to characterize the microorganisms colonizing punctal plugs and intracanalicular stents.
Devices were removed from participants who previously underwent placement of punctal plugs for tear insufficiency and lacrimal stents for dacryocystorhinostomy and canalicular reconstruction procedures. After removal of the devices, they were cultured for organisms both with and without sonication to loosen any biofilms or adherent microorganisms. Primary outcome measures included culture positivity, identification of isolated microorganisms, recovery of microorganisms from culture after sonication, and clinical evidence of ocular infection.
There were no cases of clinical infection. A total of 181 specimens were processed (174 punctal plugs, seven intracanalicular stents), of which 98 (54%) were culture positive. Of the punctal plugs, 92 (52.9%) were culture positive, including 42 with a single organism isolated, whereas 22 yielded two organisms, 7 yielded three organisms, and the remaining 21 yielded a polymicrobial culture with four or more organisms. The most common isolates from punctal plugs were coagulase negative staphylococci (27.6%), diphtheroids (16.4%), and streptococcus viridans (10.2%). Those plugs with polymicrobial culture results grew a mixture of organisms most consistent with skin or upper respiratory flora. Of the intracanalicular stents, 6 (85.6%) were culture positive.
Punctal plugs and intracanalicular devices can become colonized with bacteria composed of oropharyngeal flora, skin flora, and other rare but potentially significant pathogens.
Efficacy comparison of repeated low-level red-light therapy and orthokeratology lenses for myopia control.
Optometry and Vision ScienceThis study aimed to compare and analyze the efficacy of repeated low-level red-light therapy and orthokeratology lenses for myopia control in children.
Exactly 138 participants were enrolled in this retrospective study. Comprehensive eye examinations were performed prior to treatment. The repeated low-level red-light therapy and orthokeratology lenses groups comprised 67 and 71 patients, respectively. The age range was between 6 and 14 years, with myopia of ≤-0.50 D and astigmatism of ≤2.50 D after cycloplegia. Follow-up data were collected during the initial visit and the treatment period. Changes in axial length over a 2-year period and associated factors were analyzed.
Over the 2-year period, the repeated low-level red-light therapy group exhibited significantly less axial length growth compared with the orthokeratology lenses group (0.17 ± 0.40 vs. 0.50 ± 0.27 mm, p<0.001). In the first year, the axial length growth in the repeated low-level red-light therapy group was significantly less than that in the orthokeratology lenses group (0.03 ± 0.22 vs. 0.28 ± 0.18 mm, p<0.001), with no significant difference observed in the second year (0.14 ± 0.29 vs. 0.21 ± 0.14 mm, p=0.06). The repeated low-level red-light therapy group showed a 55% reduction in axial length after 1 month and a 42% reduction after 1 year, compared with 4% and 3% reductions in the orthokeratology lenses group, respectively. Linear mixed-effects model analysis indicated that the annual axial length change rate in the repeated low-level red-light therapy group was 0.10 mm (95% confidence interval [CI], 0.07 to 0.14), compared with 0.25 mm in the orthokeratology lenses group (95% CI, 0.24 to 0.27), with an average difference of 0.15 mm (95% CI, -0.17 to -0.12, p<0.001).
Repeated low-level red-light therapy demonstrated slightly superior efficacy in controlling myopia progression in children compared with orthokeratology lenses.
The unmet need for certification of vision impairment for people accessing a national primary care-based low vision rehabilitation service.
Ophthalmic and Physiological OpticsThe certificate of vision impairment has an important role in enabling access to support for people with vision impairment (VI) and the provision of epidemiological data regarding sight loss. However, the rates of certification may not accurately reflect the number of people living with certifiable VI.
Observational data from a national primary care low vision rehabilitation service between 1 April 2021 and 31 March 2022 were analysed. Descriptive statistics were used to describe the certification status of patients with certifiable VI. For patients with age-related macular degeneration (AMD) and best-corrected visual acuity of 6/60 or worse, logistic regression was undertaken to assess the effects of patient characteristics on certification status.
For patients with AMD and certifiable levels of visual acuity, 41.00% (n = 426) were not certified. The reported certification was 60.09% (n = 256) and 58.24% (n = 357) for neovascular AMD and atrophic AMD, respectively. Existing patients of the service were 3.87 times more likely to be certified than new patients (OR 3.87, 95% CI 2.7-5.4). Increasing age (OR 1.02, 95% CI 1.004-1.038) and decreasing visual acuity (OR 0.62, 95% CI 0.50-0.78) were associated with an increased likelihood of certification.
A significant number of patients live with certifiable vision impairment but do not access certification. Policy changes in Wales now enable patients with bilateral atrophic AMD to access certification within the primary care setting. Given the unmet need, consideration should be given to primary care certification in the rest of the UK, and in Wales, the potential to expand the scope of conditions.
Baseline factors associated with myopia progression and axial elongation over 30 months in children 5 to 12 years of age.
Optometry and Vision ScienceThis study aimed to identify baseline factors associated with greater myopia progression and axial elongation in children with myopia.
This study performed a post hoc analysis of data from a 30-month randomized trial of atropine 0.01% versus placebo in children 5 to <13 years old with baseline spherical equivalent refractive error (SER) of -1.00 to -6.00 D, astigmatism of ≤1.50 D, and anisometropia of <1.00 D SER. Data from atropine 0.01% and placebo groups were pooled given outcomes were similar. Baseline factors of age, SER, axial length, race, sex, parental myopia, and iris color were evaluated for association with changes in SER and with changes in axial length at 30 months (24 months on treatment and then 6 months off) using backward model selection.
Among 187 randomized participants, 175 (94%) completed 30 months of follow-up. The mean change in SER was greater among younger children (-0.19 D per 1 year younger; 95% confidence interval [CI], -0.25 to -0.14 D; p<0.001) and children with higher myopia (-0.14 D per 1 D more myopia at baseline; 95% CI, -0.23 to -0.05 D; p=0.002). The mean change in axial length was also greater among younger children (0.13 mm per 1 year younger; 95% CI, 0.10 to 0.15 mm; p<0.001) and children with higher baseline myopia (0.04 mm per 1 D more myopia; 95% CI, 0.002 to 0.08; p=0.04).
Younger children with higher myopia had greater myopic progression and axial elongation over 30 months than older children with lower myopia. Developing effective treatments to slow the faster myopic progression in younger children should be a target of further research.
Experiences of life and intersectionality of people with low vision: A qualitative approach.
Optometry and Vision ScienceThe results of the study show that people experience discrimination, exclusion, and stigmatization in their daily activities, which vary according to the traditionally assigned roles of gender, social class, age, and educational level, among others. Given the complexity of the experience, it is important for health and visual rehabilitation professionals to broaden their perspective and transition toward vision rehabilitation models that address the various dimensions affected by this condition.
This study aimed to describe the life experience of people with low vision from an intersectional perspective in Medellín, Colombia.
A qualitative ethnographic case study was conducted, considering the intersectional perspective as an analytical element to comprehend the everyday experience of people with low vision. Twenty-nine interviews were conducted with 10 participants, along with 16 participant observation exercises in their daily lives, with prior informed consent.
Participants experienced discrimination due to their visual condition, which had negative implications for the development of their life projects. Three categories emerged: Discrimination in everyday contexts: ocularcentrism, gender challenges in the lives of people with low vision, and challenges in seeking vision rehabilitation services.
Piggyback Scleral Contact Lens to Enhance Cosmesis and Comfort in Uniocular Stevens-Johnson Syndrome.
Eye Contact LensStevens-Johnson syndrome often results in a significant reduction in vision, dryness, and photophobia based on severity. Scleral lenses are well-co...