scholarly journals Comparison of Two Wavefront Autorefractors: Binocular Open-Field versus Monocular Closed-Field

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Gonzalo Carracedo ◽  
Carlos Carpena-Torres ◽  
Laura Batres ◽  
Maria Serramito ◽  
Anahí Gonzalez-Bergaz
Keyword(s):  
Visual Acuity ◽  
Open Field ◽  
Age Groups ◽  
Closed Field ◽  
Refractive Errors ◽  
Spherical Equivalent ◽  
Cross Sectional ◽  
Field Versus ◽  
Corrected Distance Visual Acuity ◽  
Healthy Participants

Purpose. To evaluate the agreement and repeatability between a new commercially available binocular open-field wavefront autorefractor, as part of the Eye Refract system, and a monocular closed-field wavefront autorefractor (VX110). Methods. A cross-sectional, randomized, and single-masked study was performed. Ninety-nine eyes of 99 healthy participants (37.22 ± 18.04 years, range 8 to 69 years) were randomly analyzed. Three measurements with the Eye Refract and the VX110 were taken on three different days, under noncycloplegic conditions. Mean spherical equivalent (MSE), cylindrical vectors (J0 and J45), and binocular corrected distance visual acuity (BCDVA) were compared between both autorefractors. An intersession repeatability analysis was done considering the values of repeatability (Sr) and its 95% limit (r). Results. The VX110 showed more negative values (P<0.001) in terms of MSE in comparison with the Eye Refract (0.20 D). Regarding cylindrical vectors, J45 showed statistically significant differences (P=0.001) between both wavefront autorefractors, but they were not clinically relevant (<0.05 D). In BCDVA, there were no statistically significant differences (P=0.667) between both wavefront autorefractors. Additionally, the Eye Refract was more repeatable than the VX110 in terms of both MSE (SrEYE REFRACT = 0.21 D, SrVX110 = 0.53 D) and J0 (SrEYE REFRACT = 0.12 D, SrVX110 = 0.35 D). Conclusions. The Eye Refract provided enough accuracy and reliability to estimate refractive errors in different age groups, achieving better results than the VX110. Therefore, the Eye Refract proved to be a useful autorefractor to be incorporated into clinical practice.

scholarly journals Association of range of accommodation with fully corrected refractive errors

2021 ◽  
Vol 5 ◽  
pp. 96-100
Author(s):  
Adnan Afsar ◽  
Rashid Asghar Khan ◽  
Muhammad Imshad Khan
Keyword(s):  
Visual Acuity ◽  
Social Scientist ◽  
Normal Population ◽  
Age Groups ◽  
Cross Sectional Study ◽  
Posterior Chamber ◽  
P Value ◽  
Refractive Errors ◽  
Cross Sectional ◽  
Near Vision

Background: To study whether the range of accommodation differs in myopes and hypermetropes than normal population. Purpose: To study the range of accommodation in myopes and hypermetropes in comparison to normal population in different age groups. Materials and methods: A comparative cross-sectional study was conducted at MHL from January 2018 to October 2018. Total 99 patients were enrolled in this study who had refractive errors. All patients were included who had 10 – 55 years age. Both genders were included. Both myopic and hypermetropic patients were included having fully corrected myopia and hypermetropia. Patients with any ocular pathologies were excluded. All patients who were included in this study had complete ocular and posterior chamber examination from ophthalmologist. There visual acuity was recorded using Snellen`s visual acuity chart and recorded in Snellen notation. Near vision was assessed on near vision chart. Then range of accommodation will be measured by RAF meter. All data entered and analyzed by SPSS 20 (Statically package for social scientist). Bar charts and Pie charts were used to describe qualitative data and range, mean, S.Dwere used to express quantitative data. For data normality Kolmogorov-Smirnov and Shapiro Wilktest used and showed that all parameters are non-parametric as p value is ≤ 0.05 (p = 0.000). Results: Total 99individuals were analyzed who had refractive errors. There were 60 female and 39male individuals. Avg age of individuals was 21 with standard deviation ±3. Association of rang of accommodation between hypermetropes and emmetropes during point break, Rec point and Rang D the p value is 0.001 in all points. Association of rang of accommodation between emmetropes and myopes during point break, Rec point and Rang D the p value is 0.142, 0.224 and 0.315 accordingly. Conclusion: Association of rang of accommodation is significant between emmetropes and hypermetropes (p=0.001). But there is no significant association of rang of accommodation between Myopes and emmetropes (p=0.224).

scholarly journals Refractive errors and visual impairment among children and adolescents in southernmost China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Li Peng ◽  
Ling Gao ◽  
Yunyan Zheng ◽  
Yanan Dai ◽  
Qing Xie
Keyword(s):  
Visual Acuity ◽  
Visual Impairment ◽  
High Myopia ◽  
Large Population ◽  
Population Based ◽  
Cross Sectional Study ◽  
Refractive Errors ◽  
Spherical Equivalent ◽  
Sectional Study ◽  
Cross Sectional

Abstract Background Refractive errors and visual impairment in southernmost China have not been reported previously. We aim to investigate and determine the age-specific prevalence of myopia, hyperopia, astigmatism, and visual impairment based on a large population cross-sectional study in Hainan area of southernmost tropical province in China. Methods A population-based sample of 31,524 children aged 6–15 years from Hainan was assessed. Non-cycloplegic autorefraction and visual acuity (VA) analyses were performed on all participants and a subgroup of participants undergoing cycloplegia. Results Of all participants, 23.0% presented uncorrected VA (UCVA) was worse than 20/40 in worse eye, 6.0% presented mild presenting visual acuity impairment (PVAI), 7.0% presented moderate PVAI, 0.2% presented severe PVAI in the better eye, and 46.9% presented abnormal UCVA [worse than 20/25 (≥ 6, < 8 years old) and worse than 20/20 (≥ 8 years and older)] at least in one eye. The overall prevalence of myopia [spherical equivalent (SE) ≤  − 0.50 D] and high myopia (SE ≤  − 6.00 D) were 46.0%, 1.0% respectively. Hyperopia [SE ≥  + 1.00 D (≥ 7 years old) and SE ≥  + 2.00 D (≥ 6, < 7 years old)] and significant hyperopia (SE ≥  + 3.00 D) were 4.2 and 0.6%, respectively. Astigmatism [cylinder ≥ 1.00 D (≥ 7 years old) and ≥ 1.75 D (≥ 6, < 7 years old)] was found in 31.9%. Conclusions Myopia was the most common refractive error in southernmost province in China (Hainan). Its prevalence increased with age, while hyperopia prevalence showed a decreasing trend. However, myopia, especially high myopia prevalence was much lower than in other urban regions across China.

scholarly journals Changes in Corneal Asphericity after MyoRing Implantation in Moderate and Severe Keratoconus

2019 ◽  
Author(s):  
Masoud Khorrami-Nejad ◽  
Ozra Aghili ◽  
Hesam Hashemian ◽  
Mohamad Aghazadeh-Amiri ◽  
Bahram Khosravi
Keyword(s):  
Visual Acuity ◽  
Outcome Measures ◽  
Secondary Outcome ◽  
Refractive Errors ◽  
Cross Sectional ◽  
Distance Visual Acuity ◽  
Uncorrected Distance Visual Acuity ◽  
Manifest Refraction ◽  
Corrected Distance Visual Acuity ◽  
Corneal Asphericity

Purpose: To evaluate the effect of MyoRing implantation on corneal asphericity in moderate and severe keratoconus (KCN). Methods: This cross-sectional observational study comprised 32 eyes of 28 patients with KCN, who had femtosecond-assisted MyoRing corneal implantation. The primary outcome measures were preoperative and six-month postoperative corneal asphericity in 6-, 7-, 8-, 9-, and 10-mm optical zones in the superior, inferior, nasal, temporal, and central areas. The secondary outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, thinnest location value, and keratometry readings. Results: A significant improvement in the UDVA and CDVA was observed six months after the surgery (P < 0.001) with a significant reduction in the spherical (4.67 diopters (D)) and cylindrical (2.19 D) refractive errors. A significant reduction in the corneal asphericity in all the optical zones and in the superior, inferior, nasal, temporal, and central areas was noted (P < 0.001). The mean thickness at the thinnest location of the cornea decreased from 437.15 ± 30.69 to 422.81 ± 36.91 μm. A significant corneal flattening was seen. The K1, K2, and Km changes were 5.32 D, 7 D, and 6.17 D, respectively (P < 0.001). Conclusion: MyoRing implantation is effective for improving corneal asphericity in patients with KCN. It allows successful corneal remodeling and provides a significant improvement in UDVA, CDVA, and refractive errors.

scholarly journals Repeatability of Aberrometry-Based Automated Subjective Refraction in Healthy and Keratoconus Subjects

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Gonzalo Carracedo ◽  
Carlos Carpena-Torres ◽  
Cristina Pastrana ◽  
Ana Privado-Aroco ◽  
María Serramito ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Clinical Practice ◽  
Confidence Interval ◽  
Healthy Subjects ◽  
Randomized Study ◽  
Intraclass Correlation ◽  
Refractive Errors ◽  
Cross Sectional ◽  
New Instrument ◽  
Corrected Distance Visual Acuity

Purpose. To compare the intersession repeatability of the Eye Refract, a new instrument to perform aberrometry-based automated subjective refraction, on healthy and keratoconus subjects. Materials and Methods. A cross-sectional and randomized study was performed. A total of 64 participants were evaluated in the study, selecting one eye per participant randomly. The sample was divided into two different groups: 33 healthy subjects (38.85 ± 13.21 years) and 31 with keratoconus (37.29 ± 11.37 years). Three refractions per participant with the Eye Refract were performed on three different days, without cycloplegia. The repeatability analysis of refractive variables (M, J0, and J45), binocular corrected distance visual acuity (BCDVA), and spent time in refraction was performed in terms of repeatability (Sr), its 95% confidence interval (r), and intraclass correlation coefficient (ICC). Results. There were no statistically significant differences ( P ≥ 0.05 ) between sessions in both groups for all refractive variables (M, J0, and J45) and BCDVA. Spent time in refraction was reduced as the sessions went by ( P < 0.05 ). The Eye Refract was more repeatable for refractive errors assessment in healthy subjects (M : Sr = 0.27 D; J0 : Sr = 0.09 D; J45 : Sr = 0.06 D) compared to those with keratoconus (M : Sr = 0.65 D; J0 : Sr = 0.29 D; J45 : Sr = 0.24 D), while it was similar for BCDVA. Conclusions. The Eye Refract offered better repeatability to assess refractive errors in healthy subjects compared to those with keratoconus. Despite measurements being also consistent in keratoconus subjects, they should be treated with caution in clinical practice.

Outcomes of a 320-degree intrastromal corneal ring segment implantation for keratoconus: Results of a 6-month follow-up

2018 ◽  
Vol 30 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Guilherme Andrade do Nascimento Rocha ◽  
Paulo Ferrara de Almeida Cunha ◽  
Leonardo Torquetti Costa ◽  
Luciene Barbosa de Sousa
Keyword(s):  
Visual Acuity ◽  
Spherical Equivalent ◽  
Distance Visual Acuity ◽  
Uncorrected Distance Visual Acuity ◽  
Intrastromal Corneal Ring ◽  
Corrected Distance Visual Acuity ◽  
Ring Segment ◽  
The Mean ◽  
Corneal Tomography

Importance: This study shows that a newer long-arc length intrastromal corneal ring segment is efficient and safe for keratoconus treatment. Background: To evaluate visual, tomographic results and complications of a 320-degree intrastromal corneal ring segment implantation with the femtosecond laser for keratoconus treatment. Design: A prospective, nonrandomized, and interventional study. Participants: A total of 34 eyes of 31 patients diagnosed with keratoconus were enrolled. Methods: Patients were divided into two groups based on the strategy used for 320-degree intrastromal corneal ring segment thickness selection. In one group, this selection was based on spherical equivalent (SE group) and in the other on the mean asphericity (Q group). The uncorrected and corrected distance visual acuities, spherical equivalent, K1, K2, Km, Kmax, and mean asphericity ( Q) on corneal tomography were evaluated preoperatively and at 3 and 6 months postoperatively. For astigmatism improvement, we analyzed the corneal tomographic vectorial astigmatism change preoperatively and at 6 months postoperatively. The mean follow-up period was 6.63 ± 0.96 months. Results: The mean uncorrected distance visual acuity and corrected distance visual acuity improved with a significant spherical equivalent improvement ( p < 0.05), with no differences between the 320-degree intrastromal corneal ring segment groups. All corneal tomographic parameters improved significantly ( p < 0.05) between the preoperative and postoperative intervals, with a significant better performance when we used spherical equivalent for the 320-degree intrastromal corneal ring segment thickness selection. Finally, the mean vectorial corneal tomographic astigmatism significantly improved after 6 months, again with no differences between groups. Conclusion: This study suggests that implanting a 320-degree intrastromal corneal ring segment is a safe and effective procedure for treating patients with keratoconus. It also suggests that for thickness selection spherical equivalent is the better strategy.

scholarly journals Assessment of visual acuity defects among rural adolescent students of tribal Bastar Chhattisgarh (India)

2018 ◽  
Vol 5 (10) ◽  
pp. 4335
Author(s):  
Alakh Ram Verma ◽  
Teeku Sinha ◽  
Gagandeep Singh Bhatia
Keyword(s):  
Visual Acuity ◽  
Low Cost ◽  
Refractive Errors ◽  
Community Based ◽  
Cross Sectional ◽  
Female Ratio ◽  
Adolescent Students ◽  
Eye Screening ◽  
Male To Female ◽  
Rural Adolescent

Background: Defective visual acuity is the most common problem among adolescents which, if remains uncorrected may cause refractive errors and may lead to blindness. Defective visual acuity can be tested early and corrected by spectacles. The objectives of the study were assessment of visual acuity defects among adolescent students.Methods: Present study design is cross sectional community based study. Conducted during July to September 2017 in Higher Secondary School, Pandripani. Predesigned KAP questionnaires were used to collect information and visual acuity was measured by using Snellen’s chart. Students with spectacles were tested for uncorrected and corrected visual acuity. Data was analyzed on MS Excel 2016.Results: Visual acuity defect prevalence rises with age and maximum is seen in age group 19-20 years (85%).Male to female ratio in students with defects was 52:48 Maximum defect is seen in class 12th students (34%).83% students never got their eyes checked out of which 25% had defective visual acuity. Positive attitude toward spectacles preventing normalization of eyes and spectacles leading to dependence and worsening of vision were elicited. Students whose parents have eye related problem have prevalence of 64%.83% of students advised to wear spectacles who don’t have, cost of spectacle is most common cause (80%) and is preceded by not much difference in vision after wearing (20%).Conclusions: The prevalence of visual acuity defect was high in rural adolescent. Eye screening of school going children is recommended and spectacles to be distributed free or at low cost to those students diagnosed with refractive errors.

Clinical outcomes of small incision lenticule extraction versus advanced surface ablation in low myopia

2019 ◽  
Vol 30 (6) ◽  
pp. 1278-1286 ◽  
Author(s):  
Suphi Taneri ◽  
Saskia Kießler ◽  
Anika Rost ◽  
Tim Schultz ◽  
H Burkhard Dick
Keyword(s):  
Visual Acuity ◽  
Spherical Equivalent ◽  
Small Incision Lenticule Extraction ◽  
Distance Visual Acuity ◽  
Small Incision ◽  
Surface Ablation ◽  
Uncorrected Distance Visual Acuity ◽  
Corrected Distance Visual Acuity ◽  
Spherical Equivalent Refraction ◽  
Lenticule Extraction

Purpose: To compare the visual and refractive outcomes of small incision lenticule extraction and advanced surface ablation for low myopia or myopic astigmatism. Methods: Retrospective, observational case series of our first 50 consecutive small incision lenticule extraction patients compared to refraction-matched 50 advanced surface ablation treatments with attempted spherical equivalent correction ⩽−3.5 D, astigmatism ⩽−1.5 D, and corrected distance visual acuity of 1.0 (decimal scale) or better. Only one eye per patient was included. Results: Small incision lenticule extraction: mean attempted spherical equivalent correction was −2.80 ± 0.63 D. Uncorrected distance visual acuity was 0.85 and 1.0 at days 1 and 5, respectively. At 3 months, mean spherical equivalent refraction was 0.02 ± 0.32 D (range: −0.5 to +0.75 D), mean cylinder was −0.24 ± 0.21 D (range: 0 to −0.75 D), mean uncorrected distance visual acuity was 1.27, mean efficacy index was 0.96, and mean safety index was 1.05. Uncorrected distance visual acuity was same or better than corrected distance visual acuity in 96%, astigmatism ⩽0.5 D in 98% and ⩽1 D in 100% of eyes, respectively. Advanced surface ablation: mean attempted spherical equivalent correction was −2.75 ± 0.5 D. Uncorrected distance visual acuity was 0.72 and 0.61 at days 1 and 5, respectively. At 3 months, mean spherical equivalent refraction was 0.22 ± 0.32 D, mean cylinder was −0.27 ± 0.27 D, mean uncorrected distance visual acuity was 1.21, mean efficacy index was 1.03, and mean safety index was 1.08. Conclusion: Small incision lenticule extraction for low myopia was found to be safe and effective with outcomes at 3 months similar to those obtained with advanced surface ablation while offering a quicker visual recovery.

Comparative analysis of two different types of intracorneal implants in keratoconus: A corneal tomographic study

2020 ◽  
pp. 112067212096344
Author(s):  
Mohammad-Reza Sedaghat ◽  
Hamed Momeni-Moghaddam ◽  
Michael W Belin ◽  
David P Piñero ◽  
Reyhaneh Akbarzadeh ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Spherical Equivalent ◽  
Q Value ◽  
Corneal Surface ◽  
Corrected Distance Visual Acuity ◽  
Different Types ◽  
Corneal Asphericity ◽  
Tomographic Data ◽  
Corneal Shape ◽  
Mean Differences

Objective: To evaluate changes in visual acuity and corneal tomographic outcomes at 6 months after femtosecond-laser assisted implantation of two different types of intracorneal implants in keratoconus. Methods: A total of 39 keratoconus eyes implanted with two segments KeraRing ( n = 22 eyes) or MyoRing ( n = 17 eyes) were enrolled. Tomographic data (Pentacam system, Oculus) were analyzed and correlated with enhancement in uncorrected (UDVA) and corrected distance visual acuity (CDVA). The tomographic indices were front maximum keratometry (Kmax), corneal asphericity (Q-value) on both surfaces, average pachymetric progression indices (PPI), maximum Ambrosio relational thickness (ARTmax), Belin-Ambrósio enhanced ectasia total deviation index (BAD-D), index of surface variance (ISV), vertical asymmetry (IVA), height asymmetry (IHA) and height decentration (IHD). Results: LogMAR UDVA and CDVA improved 2.1 ( p = 0.003) and 0.7 ( p = 0.074) lines with KeraRing, and 8 and 2.5 lines with MyoRing ( p = 0.001). The highest and lowest mean differences in the tomographic indices between both groups were related to ISV and IHD, respectively. Changes in all indices differed significantly between two groups except for changes in front corneal astigmatism, ARTmax, ISV, IVA, IHD and IHA ( p > 0.05). Correlation of changes in CDVA with changes in other parameters was statistically significant only for IHD in the KeraRing group, while changes in in UDVA were significantly correlated with changes in spherical equivalent, back Q-value, ISV, IVA, and IHA only in the MyoRing group. Conclusion: Both implants promote corneal shape regularization and an enhancement in UDVA in keratoconus. A considerable flattening effect and reduction in prolateness in the front corneal surface were observed with MyoRing.

Prevalence of amblyopia and its association with refraction in Chinese preschool children aged 36–48 months

2017 ◽  
Vol 102 (6) ◽  
pp. 767-771 ◽  
Author(s):  
Dan Huang ◽  
Xuejuan Chen ◽  
Hui Zhu ◽  
Hui Ding ◽  
Jing Bai ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Multivariate Analysis ◽  
Preschool Children ◽  
Eastern China ◽  
Population Based ◽  
Eye Disease ◽  
Refractive Errors ◽  
Cross Sectional ◽  
Population Based Study ◽  
Disease Study

PurposeTo determine the prevalence of amblyopia and its association with refraction in Chinese preschool children.MethodsThe Yuhuatai Pediatric Eye Disease Study, a cross-sectional, population-based study, was conducted in children aged 36–48 months in Yuhuatai District, Nanjing, China, in 2015. Visual acuity was measured in 1695 eligible children.ResultsOf the 1695 subjects, manifested amblyopia was detected in 25 children (1.47%, 95% CI 0.90% to 2.05%), including 11 and 14 with bilateral and unilateral amblyopia, respectively. Amblyopia prevalence did not differ by gender (p=0.77). Significant refractive errors were found in 22 (88.0%) of children with amblyopia, and strabismus was found in 6 (24.0%) children with amblyopia. In multivariate analysis, amblyopia was significantly associated with hyperopia (≥+2.00 dioptres (D); OR 8.81, 95% CI 3.27 to 23.69, p<0.0001), astigmatism (≥2.00 D; OR 17.90, 95% CI 6.78 to 47.21, p<0.0001) and anisometropia (≥2.00 D; OR 5.87, 95% CI 1.52 to 22.77, p<0.05).ConclusionsThe prevalence of amblyopia in children 36–48 months old in Eastern China was 1.47%. The refractive error is a major risk factor for amblyopia.

scholarly journals Refractive Errors: Prevalence and Pattern among Rural Population of Islamabad, Pakistan

2020 ◽  
Vol 9 (2) ◽  
pp. 103-108
Author(s):  
Waseem Akhter ◽  
Erum Yousafzai ◽  
Afia Matloob Rana ◽  
Shakaib Anwar
Keyword(s):  
Refractive Error ◽  
Rural Areas ◽  
Contact Lenses ◽  
Age Groups ◽  
P Value ◽  
Refractive Errors ◽  
Cross Sectional ◽  
Female Population ◽  
Common Error ◽  
Myopic Astigmatism

Background: Refractive error is the most common cause of correctable visual loss worldwide. Decreased vision due to refractive error can be easily corrected with the help of spectacles, contact lenses and refractive surgery. However, there are 42% of uncorrected refractive errors all over the world. The present study aimed to evaluate different kinds of refractive errors, its prevalence and pattern in patients from rural areas who visited our hospital in the last five years. Material and Methods: This cross-sectional study enrolled 2,138 patients, who visited eye OPD at Rawal Institute of Health Sciences, Islamabad during a period of five years i.e. from September, 2013 to September, 2018. Patients having only refractive error with an age of five years and above were included in the study.  All patients had objective refraction with automated refractometer followed by subjective refraction. Data was entered and analyzed in SPSS version 20.0. Chi-square test was used for comparing groups with a P-value of <0.05 considered as statistically significant. Results: Compound myopic astigmatism was the most common error found in our study population (n=575; 26.9%). The second most frequent complaint was simple myopia (n=501; 23.4%) followed by presbyopia (n=441; 20.6%) and mixed astigmatism (n=235; 11%). Patients with more than one refractive error included 178 (8.3%) with mixed astigmatism and presbyopia and 78 (3.6%) with simple myopia and presbyopia. Compound myopic astigmatism was more prevalent in younger ages compared to older age groups (46.4% vs 19.9%) (P <0.001). Mixed astigmatism (12.4% vs 8.9%), simple myopia (23.8% vs 22.9%) and presbyopia (21.3% vs 19.5%) were slightly greater in females than males (P=0.07), respectively. Conclusions: The prevalence of myopia is significantly higher among female population and young individuals. Mixed astigmatism combined with presbyopia is more common among elderly population.

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