189 research outputs found
Oxygen in Corneal Collagen Crosslinking to Treat Keratoconus: A Systematic Review and Meta-Analysis
No full textPURPOSE: Keratoconus is a disorder that results in visual loss from increased corneal high-order aberrations and irregular astigmatism and reduces quality of life. The primary treatment for progressive keratoconus is crosslinking (CXL). Recently, it has been suggested that oxygen enhances the type II photodynamic reaction of CXL that is oxygen dependent. Our study investigated the effect of increased oxygen availability in epithelium-on CXL on visual acuity and corneal curvature. METHODS: We searched PubMed, EMBASE, Medline, Web of Science, and Scopus databases on November 3, 2021. We included studies that reported increased oxygen availability during CXL in patients with keratoconus published within the last 10 years. A meta-analysis on the primary outcomes, maximum keratometry, and corrected distance visual acuity, was conducted. RESULTS: The search yielded 108 publications which were screened and assessed for eligibility. Six studies were included in the systematic review and 5 studies were included in our meta-analysis of the outcomes of increased oxygen availability in accelerated CXL. The meta-analysis on data after 6 months of follow-up found a significant decrease in mean maximum keratometry of 1.2 diopter (95% confidence interval: 0.2-2.3; P =0.02) and an improvement in mean corrected distance visual acuity by 0.08 logMAR (95% confidence interval, 0.02-0.13; P =0.01). There were no serious adverse events reported. CONCLUSIONS: Increasing oxygen during epithelium-on CXL improved visual acuity and produced corneal flattening without any serious adverse events in patients with keratoconus. The demarcation line depth was significantly higher with oxygen compared to the control group. Further data are required with a control group and long-term follow-up across a range of CXL protocols for implementation into standard clinical practice.Full Tex
Understanding unmet need and addressing access to eye health services in Aotearoa New Zealand
No full textBackground
The leading causes of vision impairment have effective interventions, but differential access to eye health services mean some population groups experience worse eye health. Inequity in eye health has historically received little attention in New Zealand.
Aim
The overarching aim was to assess vision impairment and access to eye health services in New Zealand.
Methods
Four complementary mixed-methods studies were undertaken. First, a systematic scoping review summarised the extent of evidence on vision impairment and access to eye health services in New Zealand. The remaining studies were within a project that provided cost-subsidised eye examinations and treatment to adults from an underserved community. The second study explored eye health and previous eye health service use of this cohort. The third evaluated the impact of spectacle correction on vision related quality of life at three and 12-months after spectacle correction. Lastly, a qualitative study explored barriers and facilitators of accessing eye care.
Results
The scoping review highlighted that most evidence on access to eye health services in New Zealand focused on cataract or diabetic retinopathy, with Māori and Pacific people consistently underserved; few studies focused on uncorrected refractive error. A total of 242 adults (63% female, median age 64 years) participated in the community-based study (60% Pacific people, 25% Māori), most of whom had distance or near vision impairment and half of whom (53%) reported never previously accessing optometry care. Most vision impairment was caused by uncorrected refractive error (85%), yet three-quarters of participants reported never having had custom-made spectacles (73%). Among the 207 people dispensed spectacles, quality of life was significantly higher at three-months, and this was maintained at 12-months. Cost was a major barrier to accessing eye care, while patient-provider communication was an important facilitator.
Conclusion
Ethnic disparity in access to eye care is evident in New Zealand. This research uncovered considerable unmet need for refractive error correction in an underserved community, largely due to prohibitive cost of seeking care, while correcting this refractive error significantly improved quality of life. Equity-focused strategies are required to achieve universal health coverage for eye health, including financial protection for those unable to access eye care
Computational study for temperature distribution in ArF excimer laser corneal refractive surgeries using different beam delivery techniques
No full text4 figures.Refractive errors are the most common causes of vision impairment worldwide and laser refractive surgery is one of the most frequently performed ocular surgeries. Clinical studies have reported that approximately 10.5% of patients need an additional procedure after the surgery. The major complications of laser surgery are over/under correction and dry eye. An increase in temperature may be a cause for these complications. The purpose of this study was to estimate the increase in temperature during laser refractive surgery and its relationship with the complications observed for different surgical techniques. In this paper, a finite element model was applied to investigate the temperature distribution of the cornea when subjected to ArF excimer laser at a single spot using various beam delivery systems (broad beam, scanning slit, and flying spot). The Pennes bio-heat equation was used to predict the temperature values at different laser pulse energies and frequencies. The maximum temperature increase by ArF laser (500Hz frequency and 0.5J pulse energy) at a single spot was 33.94∘C,15.86∘C,12.48∘C for 6 diopter correction (65.4μm of ablation of corneal stroma) using broad beam, scanning slit, and flying spot beam delivery approaches respectively. The peak temperature due to a single pulse was estimated to be 234.14∘C. Although the peak temperature (sufficient energy to break intermolecular bonds) exists for a very short time (10−30ns) compared to the thermal relaxation time (2000−10,000μs), there is some thermal energy exchange between corneal tissues during a laser refractive surgery. Heating may cause collagen denaturation, collagen shrinkage, and more evaporation and hence proposed to be a risk factor for over/under correction and dry eye.Peer reviewe
The mitochondrial genome of Ophiostoma himal-ulmi and comparison with other Dutch elm disease causing fungi.
No full textThe mitochondrial genome of Ophiostoma himal-ulmi, a species endemic to the Western Himalayas and a member of the Dutch elm disease-causing fungi, has been sequenced and characterized. The mitochondrial genome was compared with other available genomes for members of the Ophiostomatales, including other agents of Dutch elm disease (Ophiostoma ulmi, Ophiostoma novo-ulmi subspecies novo-ulmi and Ophiostoma novo-ulmi subspecies americana) and it was noted that gene synteny is highly conserved and variability among members of the Dutch-elm disease-causing fungi is primarily due to the number of intron insertions. Among the Dutch elm disease-causing fungi examined, O. himal-ulmi has the largest mitochondrial genomes ranging from 94 934 bp to 111 712 bp due to the expansion of the number of introns.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Epithelium-on versus epithelium-off corneal collagen crosslinking for keratoconus: a systematic review and meta-analysis
No full textPurpose
Corneal collagen crosslinking (CXL) is the primary treatment for progressive keratoconus which has a significant impact on vision and quality of life. Our study aimed to compare the efficacy and safety of epithelium-on versus epithelium-off CXL to treat keratoconus.
Methods
We searched PubMed, Medline, Embase, Web of Science, and Scopus databases. We included studies that compared standard epithelium-off with epithelium-on CXL. The primary outcome measures were changes in corrected distance visual acuity (CDVA) and maximum keratometry (Kmax), and the secondary outcomes were uncorrected distance visual acuity (UDVA), central corneal thickness (CCT), and adverse events. A meta-analysis was performed on the primary and secondary outcomes based on the weighted mean differences between baseline to 12-month follow-up.
Results
The search retrieved 887 publications with 27 included in the systematic review. A total of 1622 eyes (1399 patients; age 25.51 ± 4.02 years) were included in comparisons of epithelium-off to epithelium-on CXL in keratoconus. Epithelium-off CXL treated 800 eyes and epithelium-on CXL for 822 eyes. At 12-month follow-up, CDVA and Kmax showed no significant difference between the epithelium-off and epithelium-on CXL. The secondary outcomes showed that UDVA was better in epithelium-off CXL (− 0.11D, 95% CI − 0.12, − 0.1; p < 0.001) and there was more thinning in CCT in epithelium-off CXL (− 3.23 μm, 95% CI − 4.64, − 1.81; p <0.001).
Conclusion
Epithelium-off and epithelium-on CXL were both effective to treat progressive keratoconus. Further research is needed to compare the long-term outcomes and safety of both CXL protocols for adaptation into clinical practice.Full Tex
Impact of refractive error on quality of life: a qualitative study
No full textData source: Supporting information, https://doi.org/10.1111/ceo.12954
Link to a related website: https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/ceo.12954, Open Access via UnpaywallImportance: This study qualitatively explores the impact of refractive error on adults, particularly after correction. Background: The study aimed to explore the impact of refractive error on quality of life. Design: Cross-sectional; in-depth telephone and face-to-face semistructured interviews; qualitative study with inductive and deductive processes. Participants: Forty-eight adults with refractive error (including presbyopia) were recruited from the Flinders Vision, the Ashford Advanced Eye Care and among Flinders University staff and students, in South Australia. Methods: The interviews were audio-recorded, transcribed verbatim, coded and analysed using thematic analysis. Main Outcome Measures: Themes and categories Results: The median age of the participants was 49 years (min: 22 years; max: 76 years). Most of them were female: (29; 59%). Most of them (36; 75.0%) had myopia followed by hyperopia (12; 25.0%). Twenty-two (45.8%) participants had astigmatism. Similarly, 23 (47.9%) of them were presbyopes. Most of the participants (39; 81.3%) wore glasses; 17 (35.4%) used contact lenses, and 17 (35.4%) had undergone refractive surgery. A total of 2367 comments were coded. Thematic analysis resulted into six themes that informed about quality of life issues in people with refractive error. Concerns about cosmetic appearance, personal health and safety, difficulties in day-to-day activities and inconveniences rendered in daily life were identified as the most important themes. Conclusions and Relevance: The findings of this study enrich the understanding on the issues important in people with refractive error. The quality of life issues identified will be used to develop a refractive error-specific item bank.Himal Kandel, Jyoti Khadka, Michael Goggin and Konrad Pesudov
Letter: Pervasive Blindness and ocular morbidity in the Chepang people of Nepal
No full textThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
Oculo-visual disorders in albinism
No full textOculo-visual disorders in Albinism Safal Khanal OD, Amrit Pokharel BOptom, Himal Kandel Msc.PHEC Background and aim: Albinism poses a significant threat to visual functions and causes remarkable ocular morbidity often resulting in visual disabilities. The study aimed at describing the visual status in patients with diagnosed cases of complete oculocutaneous albinism attending a tertiary eye hospital in Nepal. Methods: This was a cross-sectional descriptive hospital-based study of all diagnosed oculocutaneous albinotic cases (16 males and 9 females; mean age, 16 years) who visited Department of Ophthalmology at the Institute of Medicine, for ocular consultation between September 1, 2011 and December 1, 2013. Results: Twenty-five cases (50 eyes) with oculocutaneous albinism were enrolled in the study. All the participants had maximally reduced visual acuity (mean: 1.24±0.50 logMAR). Myopic astigmatism was the most common refractive error (n=17; 34%). 58% of all participants had with-the-rule astigmatism. Considering the spherical equivalent power, most of the eyes (n=30; 60%) had myopia, with overall mean SE refractive error of -1.59 ± 5.39 D. Visual acuity improved significantly with refractive correction in place (paired sample t-test, p<0.05). Horizontal pendular nystagmus was the most common nystagmus (n= 34 eyes; 68%). Alternating esotropia and alternating exotropia each were observed in 16% of participants who had strabismus (40% of all cases). The diaphanous iris, foveal hypoplasia and poliosis were the most consistent clinical features. Conclusion: Oculocutaneous albinos present with a broad spectrum of visual deficits that impair visual functions. Significant improvement in visual acuity following optical correction serves as an impetus to the reduction of visual disabilities in individuals with albinism. Keywords: albinism; esotropia; Nepal; nystagmus; refractive error; visual acuityhttp://www.asiapacificoptometry.org/doc/20apoc/20th_APOC_Conference_Tentative%20Programme_final.pd
Teacher Education Admission Test Result in Mathematics: Basis for Pedagogical Enchancement
No full textCollege admission test is not an uncommon occurrence in an incoming freshman’s journey. It is a measure of his/her aptitude and a guage whether he/she will be admitted in a higher education institution. Guimaras State College (GSC) conducts admission test yearly to all its incoming freshmen. This study looked into the admission test performance of all the 90 incoming freshmen to the College of Teacher Education of the GSC-Salvador campus, specifically looking into the mathematics outcome. It is aimed to determine whether pedagogical enhancement in mathematics is necessary. The study employed a descriptive methodology and utilized mean, percentage and rank as its statistical tool. The 90 incoming freshmen was composed of all the test-takers from 2015 to 2019 which is inclusive of four academic years. The office of the Guidance Counselor provided the data which was used in this study. It was found out in these data that the takers performed as “average” in their mathematics questions, which was composed of basic mathematics, algebra, geometry, trigonometry and statistics. It also showed that the students performed best in trigonometry and poor in basic mathematics. There were salient topics identified in each mathematics area where the students performed either good or poor. The author recommended, based on the outcome, that pedagogical enhancement be employed to improve student learning and performance.
Optometry in Nepalese Context: The Profession Beyond Providing Refraction Services
No full textOptometry is an independent profession which is specialised for providing comprehensive eye care including refraction and dispensing services, diagnosis and management of eye diseases and visual rehabilitation. In clinical settings of Nepal, optometrists are primarily recognised as refractionists and are provided with working opportunities in the same area. This report highlights other optomet- ric services such as binocular vision, multifocal lenses, contact lenses and occupational lens design which can be provided by optometrists besides performing refraction and prescribing spectacles. Considering large proportion of optometrists with further education and being working outside the country, new specialised services can be introduced through training and workshop to the fellow optometrists so that specialised services can reach up to the public level.
Keywords: Nepal; optometry; refraction services
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