Snellen Visual Acuity Chart Research Articles

Laser induced retinal injury sustained in a recreational laser show

We report case of a 24-year-old man, who presented with sudden unilateral visual loss after watching streetside laser light show. The Best Corrected Visual Acuity in his left eye was 6/60 with Snellen Visual Acuity Chart. Fundoscopic examination demonstrated a preretinal haemorrhage in the left eye over the macula. Optical Coherance Tomography demonstrated subhyaloid and Sub Internal Limiting Membrane localization of the haemorrhage. Patient was unwilling for the surgical intervention advised. With conservative management, the patient’s vision improved to 6/18 in the same eye with resolution of haemorrhage and Retinal Pigment epithelial atrophy at the macula.

Time to achieve best postoperative visual acuity following Boston keratoprosthesis surgery

Background/aimsTo evaluate the time needed for patients with Boston type 1 keratoprosthesis (KPro) to reach their best-corrected visual acuity (BCVA) and all contributing factors.MethodsWe retrospectively reviewed 137 consecutive eyes from...

Epidemiological Findings of Refractive Errors and Amblyopia among the Schoolchildren in Hatta Region of the United Arab Emirates

Introduction: Uncorrected refractive errors and amblyopia pose a major problem affecting schoolchildren. We had previously observed that many schoolchildren in the Hatta region presented to the ophthalmology clinic with uncorrected refractive errors and amblyopia, which led us to undertake this research. As per the WHO, the term “visual impairment” can be “low vision” or “blindness.” Based on the presenting vision, “low vision” is defined for children who have vision of <6/18 to 3/60 or having visual field loss to <20° in the better-seeing eye. Children defined to have “blindness” have presenting vision of <3/60 or corresponding visual field of <10°. Purpose: To estimate the magnitude of uncorrected refractive errors and amblyopia among the schoolchildren aged 6–19 years and to assess the efficacy of school-based refractive error screening programs in the Hatta region of the United Arab Emirates. Methods: An epidemiological, cross-sectional, descriptive study was conducted on the entire student population studying in the government schools of the region. Those who failed the Snellen visual acuity chart test and those who were wearing spectacles were evaluated comprehensively by the researcher in the Department of Ophthalmology of the Hatta Hospital. Data were entered in the Refractive Error Study in School Children (RESC) eye examination form recommended by the WHO, and were later transferred to Excel sheets and analyzed by SPSS. Results: 1,591 students were screened and evaluated from the end of 2016 to mid-2017. About 21.37% (n = 340) had impaired vision with 20.9% (n = 333) refractive errors, of which 58% were uncorrected. Among the refractive error group, 19% (64 subjects) had amblyopia (4% of total students). The incidence of low vision was 9.5% and blindness was 0.38%. Low vision was found to be 9.5% and blindness 0.38%, taking in to account presenting visual acuity rather than best-corrected visual acuity for defining low vision and blindness. Conclusion: A significant number of students were detected to have uncorrected refractive errors among the vision impaired group (59%, n = 197) despite a school-based vision screening program in place. Seventy-eight percent of the amblyopia cases (n = 50) were found to be in the 11–19 years age group. Noncompliance with optical corrections was the reason for the high number of cases. A rigorous vision screening program and refractive services, complimented with awareness among parents and teachers, are recommended.

Correlation of contrast sensitivity with the severity of primary open angle glaucoma

Aims: To assess the contrast sensitivity (CS) in different stages of primary open angle glaucoma and to correlate it with the severity (mild, moderate & severe) of glaucoma. Materials and Methods: This prospective randomized study was conducted at Sapthagiri institute of medical sciences and research centre, Bangalore between June 2017 & December 2017. A total of 100 eyes of 55 individuals aged 25-80 years diagnosed with POAG were enrolled in this prospective study. Selected subjects underwent detailed ophthalmic examination including ocular history, slit lamp examination, objective & subjective refraction (if required) to obtain best corrected visual acuity (BCVA) on Snellen visual acuity chart and dilated fundus evaluation using indirect ophthalmoscopy. Eyes with clear media and ?BCVA 6/60 were included and contrast sensitivity was measured using Pelli Robson chart at 1 meter distance. HFA report of included subjects were collected from Glaucoma department to classify them in to mild, moderate and severe groups according to their visual field findings (pattern deviation of HFA report). Classification was done according to International statistical classification of disease and related health problem (ICD 10). One way ANOVA and t-test was used to analyze the data. Results: There was 36% mild, 26% moderate and 38% severe cases of POAG classified according to ICD 10. The mean value of contrast in mild, moderate and severe POAG was 1.4341, 1.3267 and 1.1326 respectively. An analysis of variance tested whether there were significant difference in contrast sensitivity among mild, moderate and severe POAG. Results indicated that these means differed significantly p < 0> Conclusion: There was decrease in contrast sensitivity with the severity of POAG. Thus the contrast sensitivity testing should be made mandatory in evaluating POAG patients which could help in screening/diagnosis (early detection) and to assess the progression of the disease as well as response to the tre

Efficacy and Safety of Infliximab in HLA-B27-associated Ocular Inflammation Refractory or Intolerant to Conventional Immunomodulatory Therapy.

PurposeTo determine the efficacy and safety of infliximab therapy in patients with HLA B-27-associated ocular inflammation resistant or intolerant to conventional immunomodulatory therapy.MethodsThis was a retrospective observational case series. All cases were uveitic patients with positive HLA-B27, confirmed through HLA testing, resistant or intolerant to conventional immunomodulatory therapy. The primary outcome of the study was to identify the efficacy of infliximab determined by the control of inflammation, duration of remission, and the ability to reduce conventional immunomodulatory therapy. The secondary outcome was an improvement of two or more lines of best-corrected visual acuity (BCVA) on the Snellen visual acuity chart.ResultsTwenty-four patients (38 eyes) were included in the study. All patients were followed for 24 months. Twenty-one (87.5%) patients completed 24 months of follow-up. Sixteen (66.7%) patients had active uveitis at the beginning of therapy. One patient out of these active patients had active inflammation at the end of follow-up period. Thirteen (87.5%) out of sixteen active patients were in steroid-free remission. The mean duration of treatment to induce remission was 16.5 months (range 6–24 months). Corticosteroid was stopped in 19 (90.5%) patients by the end of the study. At the end of the study, in patients who achieved remission, 14 (58.3%) patients were in remission on infliximab therapy and 6 (25%) patients were in remission off infliximab therapy. Of the 38 eyes, 8 (21.05%) showed improvement in BCVA (three eyes had successful cataract extraction with intraocular lens implantation during infliximab therapy with no subsequent inflammation), while 26 eyes (68.4%) had stable BCVA over the 24-month study period. The side effects included allergic reaction, fatigue, cellulitis, headache, restlessness, elevation of liver enzymes, and anemia. Two patients (n = 24, 8.3%) experienced severe adverse effects and the treatment was stopped prematurely in these two patients.ConclusionInfliximab might induce and maintain the steroid-free remission in HLA-B27-associated ocular inflammation in patients resistant or intolerant to conventional immunomodulatory therapy.

Comparison of the Snellen and Spectrum LogMAR visual acuity charts in schoolgoing children

ackground: This article is part of a doctoral study conducted by Dr T.I. Metsing under the supervision of Dr W. Jacobs and Dr R. Hansraj. Aim: To investigate the equivalence of a standard Snellen chart to that of the Spectrum LogMAR chart amongst children of school-going age. Setting: The study was conducted through the University of Johannesburg, with data collected from the district of Ekurhuleni in the province of Gauteng, in South Africa. Methods: Visual acuity (VA) data on uncompensated distance was collected from three randomly selected schools in Gauteng from 206 children aged between 6 and 17 years (mean age and standard deviation of 10.13 ± 2.45 years). Unaided monocular and binocular VAs were measured using the Snellen chart (SC) at 6 m and the Spectrum LogMAR chart (SLC) at 3 m. Data was analysed using the Statistical Package for Social Sciences software. Results: The mean VAs of both eyes (BE), right eye (RE) and left eyes (LEs) obtained using the SLC of 0.84 minutes (6/5), 0.91 (6/5.5) and 0.96 (6/5.8), respectively, fell within the normal ranges of 6/6 or better. The mean VA scores of BE, RE and LEs obtained using the SC were 1.07 min (6/6.4), 1.11 min (6/6.7) and 1.18 (6/7.1), respectively, and fell below 6/6. The difference in the mean VAs scores for the SC and SLC of BE, RE and LE were found to be statistically significant ( p = 0.00). Conclusion: Monocular and binocular mean VAs for the SLC were found to be one line better than that for the SC. The slightly better performance of the SLC could be attributed to potential theoretical advantages of the LogMAR chart.

Evaluation of macular and retinal nerve fibre layer thickness in unilateral amblyopic patients by using optical coherence tomography

Aim: To evaluate the macular and the retinal nerve fiber layer thickness in patients with unilateral amblyopia. Design: Prospective observational study. Material and Methods: 188 eyes of 94 patients with unilateral amblyopia diagnosed by difference of at least two lines between the normal and amblyopic eye on Snellen visual acuity charts was included. Statistical analysis: Unpaired sample t-test.Results: Majority of the cases was seen in age group 21-30 years with male preponderance. The average macular thickness was 271.4µm for normal eye versus 278.0µm for amblyopic eye, values by unpaired t-test was t-value=3.169, p=0.002

Visual outcome of Pars Plana Vitrectomy following Endophthalmitis – A Vitreo-retinal Surgeon's Experience

Purpose: To determine the visual outcome of pars plana vitrectomy following endophthalmitis.&#x0D; Methods: A retrospective hospital-based study of 20 eyes of consecutive patients who had pars plana vitrectomy by a particular surgeon following endophthalmitis in the Ispahani Islamia Eye Institute and Hospital, Dhaka, Bangladesh from August – December 2017. Using the Snellen's visual acuity chart, post-operative distant visual acuity improvement was graded 0– 9, with 0 meaning no improvement in visual acuity, and 9 meaning nine lines of improvement in visual acuity from presenting best corrected visual acuity.&#x0D; Results: Pre-operative corrected distant visual acuity (CDVA) ranged from perception of light to 6/36. Seventy percent of the patients had postoperative visual improvement of varying degrees. The mean pre-operative and post-operative CDVA were 2.20 logMAR and 1.40 logMAR respectively. All the patients tractional retinal detachment and corneal laceration with rhegmatogeneous retinal detachment as co-morbidities did not have visual improvement, and this was statistically significant (p-value = 0.007). There was an association (although not strong) between age range and postoperative visual improvement (p-value = 0.639).&#x0D; Conclusion: Pars plana vitrectomy helps to prevent or minimize ophthalmic complications from endophthalmitis, thus making it a necessary line of treatment endophthalmitis. Pars plana vitrectomy is therefore a safe and desirable definitive treatment for endophthalmitis, and it confers a good chance of visual improvement.

Redefining vision assessment.

This review outlines ophthalmic diagnostic systems, which objectively evaluates the human visual system and its potential beyond that of Snellen acuity. Advances in ophthalmic diagnostic systems have allowed for a deeper understanding of the optical principles of the human eye and have created the opportunity to evolve our current standards of vision assessment beyond Snellen acuity charts. Definitive comparative and validation trials will continue to be necessary in order for these advanced diagnostics to gain more widespread acceptance in the specialty, in addition to providing the guidance on the specific indications and utilities. Advancements in wavefront analysis, light scatter measurements, and adaptive optics technologies can provide greater insight into an individual optical system's potential and irregularities. Modalities that test for anterior corneal surface and whole eye aberrations, light scatter and contrast sensitivity can be an excellent educational tool for our patients to help them better understand their visual dysfunction and can prove useful for medical or surgical decision-making.

Central Corneal Thickness in Females Using Oral Contraceptive Pills

Purpose: To compare the central corneal thickness in females using oral contraceptive pills (OCP) with age matched controls.&#x0D; Study Design: Descriptive Observational study.&#x0D; Place and Duration of Study: Department of ophthalmology, University of Lahore teaching hospital, from August 2018 to December 2018.&#x0D; Material and Methods: Fifty-one females who used OCP within last one year and 38 age-matched controls were included in this study after approval from the ethical review board. Females with any systemic disease, pregnancy and lactating mothers were excluded from the study. Females with ocular diseases, like trachoma, cataract, keratitis, uveitis, corneal dystrophies, Keratoglobus, Keratoconus, ocular trauma, and high refractive errors were also excluded. Each subject underwent full ocular examination including best-corrected visual acuity using Snellen acuity chart and Bio-microscopic examination of anterior segment and the fundus. Central corneal thickness (CCT) was measured with ultrasonic pachymeter and the intraocular pressure was measured with noncontact tonometer at the time of examination. The data was collected by self-designed proforma and analyzed by using SPSS version 20.&#x0D; Results: Mean age of the females using OCP was 31.4 ± 6.8 years and mean age of age-matched controls was 32.9 ± 5.5 years (p = 0.38). Mean Central corneal thickness values were higher in OCP group when compared to controls (541.8 ± 31.39μm and 518.7 ± 36.7 μm, respectively). P value was 0.004, which was statistically significant. The mean IOP value was 14.5 ± 2.6 mm Hg in OCP group and 14.4 ± 2.8 mm Hg in the control group (P = 0.86), which was not statistically significant.&#x0D; Conclusion: Central corneal thickness values are significantly higher in patients using OCP.

Visual outcome of Pars Plana Vitrectomy following Endophthalmitis – A Vitreo-retinal Surgeon's Experience

Purpose: To determine the visual outcome of pars plana vitrectomy following endophthalmitis.&#x0D; Methods: A retrospective hospital-based study of 20 eyes of consecutive patients who had pars plana vitrectomy by a particular surgeon following endophthalmitis in the Ispahani Islamia Eye Institute and Hospital, Dhaka, Bangladesh from August – December 2017. Using the Snellen's visual acuity chart, post-operative distant visual acuity improvement was graded 0– 9, with 0 meaning no improvement in visual acuity, and 9 meaning nine lines of improvement in visual acuity from presenting best corrected visual acuity.&#x0D; Results: Pre-operative corrected distant visual acuity (CDVA) ranged from perception of light to 6/36. Seventy percent of the patients had postoperative visual improvement of varying degrees. The mean pre-operative and post-operative CDVA were 2.20 logMAR and 1.40 logMAR respectively. All the patients tractional retinal detachment and corneal laceration with rhegmatogeneous retinal detachment as co-morbidities did not have visual improvement, and this was statistically significant (p-value = 0.007). There was an association (although not strong) between age range and postoperative visual improvement (p-value = 0.639).&#x0D; Conclusion: Pars plana vitrectomy helps to prevent or minimize ophthalmic complications from endophthalmitis, thus making it a necessary line of treatment endophthalmitis. Pars plana vitrectomy is therefore a safe and desirable definitive treatment for endophthalmitis, and it confers a good chance of visual improvement.

Commentary: Preferred practice pattern for primary eye care in the context of COVID-19 in L V Prasad Eye Institute network in India.

Commentary: Preferred practice pattern for primary eye care in the context of COVID-19 in L V Prasad Eye Institute network in India.

Therapeutic effect of vitrectomy combined with single-layer inverted internal limiting membrane flap covering technique for rhegmatogenous retinal detachment complicated with macular hole

Objective To observe the therapeutic effect of vitrectomy combined with single-layer inverted internal limiting membrane (ILM) flap covering technique for rhegmatogenous retinal detachment(RRD) complicated with macular hole (MH). Methods A retrospective case analysis. From January 2015 to August 2019, 29 eyes of 29 patients with RRD and MH diagnosed in the First People's Hospital Affiliated to Shanghai Jiaotong University were included in this study. There were 16 males (16 eyes) and 13 females(13 eyes). All the eyes were peripheral RRD and involving the macular area, while complicated with MH and proliferative vitreoretinopathy in stage less than C. All the eyes were examined by BCVA and OCT. The BCVA examination was performed using the Snellen visual acuity chart, which was converted into logMAR visual acuity. Before 2017, 18 eyes were treated with vitrectomy combined with ILM peeling (ILM peeling group); after 2017, 11 eyes were treated with vitrectomy combined with single-layer inverted ILM flap covering technique (ILM inverted group). The differences of age (t=0.360), onset time (t=1.235), number of holes except MH (t=0.060), RRD range (t=1.232), gas filled eyes (χ2=0.324) between the two groups were not statistically significant (P>0.05). The average follow-up time after surgery was 4.5 months. The BCVA, retinal reattachment and MH closure at the last follow-up in the two groups were comparatively observed. U-shaped or V-shaped retina was defined as MH closure. Results At the last follow-up, retinal reattachments were achieved in all the eyes. In ILM peeling group, 5 eyes (27.8%, 5/18) were completely closed in typeⅠ . In ILM inverted group, 9 eyes (81.8%, 9/11) were completely closed in typeⅠ . There was a statistically significant difference of closure rate in type Ⅰ closure between the two groups (χ2=5.968, P=0.015). The mean logMAR BCVA in ILM peeling group and ILM inverted group were 1.24±0.28 and 0.97±0.39, respectively. The difference of logMAR BCVA between the two groups was statistically significant (t=2.179, P=0.038). Conclusion Vitrectomy combined with single-layer inverted ILM flap covering technique can increase the BCVA and MH closure rates in RRD patients with MH. Key words: Retinal perforations/surgery; Retinal detachment/surgery; Vitreoretinal surgery

Effect of internal limiting membrane peeling and transplantation on vision-related quality of life in refractory macular hole

Objective To observe the effect of internal limiting membrane peeling and transplantation on vision-related quality of life in refractory macular hole. Methods A retrospective clinical study. Thirty patients (30 eyes) with refractory macular hole diagnosed in Ophthalmology Department of The First Affiliated Hospital of Nanjing Medical University from January to December 2016 were included in this study. There were 13 males (13 eyes) and 17 females (17 eyes), with the mean age of 57.3±6.9 years. There were 15 patients(15 eyes) with large macular diameter, 12 patients (12 eyes) with high myopia macular hole, and 3 patients (3 eyes) with secondary traumatic macular hole. The BCVA examination was performed using the Snellen visual acuity chart, which was converted into logMAR visual acuity. OCT was performed to measure the macular retinal thickness (CRT), base diameter and minimum diameter of macular hole. Then, the macular hole index(MHI) was calculated. The logMAR BCVA was 1.52±0.30, MHI was 0.51±0.19. The Chinese version of visual-related quality of life scale-25 (CVRQoL-25) was used to evaluate the vision-related quality of life of patients. The CVRQoL-25 score was 57.60±7.13. All patients underwent 23G vitrectomy combined with inner limited membrane peeling and autologous ILM transplantation. The follow-up was at least 3 months after surgery. The changes of BCVA, MHI, CRT and CVRQoL-25 score before and after surgery were comparatively analyzed. Paired t test was performed to compare the measurement data before and after surgery, and Spearman rank correlation analysis was used for the correlation analysis among the parameters. Results At 3 months after surgery, the hole closure was detected in 28 eyes (93.3%), not detected in 2 eyes (6.7%). The logMAR BCVA was 1.16±0.33, CRT was 161.00±15.26, and CVRQoL-25 scores was 70.83±9.77. Compared with before surgery, the BCVA (t=4.386, P=0.000) and CVRQoL-25 score (t=-5.991, P=0.000) after surgery were improved. Spearman rank correlation analysis showed that CVRQoL-25 score was negatively correlated with preoperative and postoperative logMAR BCVA (r=−0.536, −0.796; P=0.002, 0.000); positively correlated with preoperative MHI (r=0.421, P=0.020) and postoperative CRT (r=0.589, P=0.001). Conclusion Internal limiting membrane peeling and transplantation for refractory macular hole can significantly improve the vision-related quality of life and visual acuity, while achieved a high hole closure rate (93.3%). Key words: Retinal perforations/surgery; Vitrectomy; Internal limiting membrane peeling; Internal limiting membrane transplantation; Vision-related quality

Prevalence of Refractive Errors Among the Children of Special Education Complex, Peshawar

OBJECTIVES:The objective of our study was to determine the prevalence of refractive errors among children of special education complex.&#x0D; METHODOLOGY:A cross-sectional study was conducted to determine refractive error among the children of special education complex Hayatabad, Peshawar. A total of 272 children were examined from age 5-19 years. Refractive errors were determined by doing retinoscopy, subjective and objective refraction, ophthalmoscope and, hand held auto refractors. Snellen’s charts, lea symbol chart and kay pictures were used for assessing the visual acuity in children who could cooperate.&#x0D; RESULTS:Among 272 children, 225 children were males (82.7%). 34(12.5%) were mentally retard, 182(66.9%) were hearing impaired and 56(20.6%) were physically handicapped. Children suffering from refractive errors were 47(17.3%). 11(4.0%) reported that they were using glasses. Squint was present in 5(1.8%). On examination status of right eye 5(1.8%) were with visual acuity 6/60 or less. For children who were unable to comprehend with Snellen visual acuity chart, they were be assessed by using other charts like Lea symbol chart or Kay pictures. 19(7.0%) were assessed by Lea symbol chart, 9(3.3%) by Kay pictures and maximum number of children easily understand Snellen visual acuity chart that was 244(89.7%).&#x0D; CONCLUSION:This study concluded that refractive errors were common in special children.

Multifocal Electroretinography in Assessment of Macular Function after Internal Limiting Membrane Peeling in Macular Hole Surgery.

Purpose Internal limiting membrane (ILM) peeling is important for macular hole (MH) surgery but may have secondary effects visible on spectral domain optical coherence tomography (OCT) and multifocal electroretinography (mfERG). We relate integrity of inner and outer macular layers with functional results with mfERG. Methods Nonrandomized prospective study of 33 consecutive eyes of 33 patients with macular hole who underwent vitrectomy with ILM peeling. Best-corrected visual acuity was assessed, and integrity of external layers was measured using OCT. Each component of mfERG, N1 and P1 amplitude and latency, was also measured. Results All eyes showed macular hole closure. Visual acuity improved from 20/400 to 20/40 in the Snellen visual acuity chart (P < 0.001), and OCT external lines were intact in 19 eyes and disrupted in 14 eyes. Postoperatively, N1 and P1 amplitudes in ring 1 increased compared to preoperative values (P < 0.001 for both). Latency remained delayed for both N1 and P1 wave. In the group of 19 eyes with integrity of outer retinal layers, N1 amplitude in ring 1 was superior to the group of 14 patients with disrupted outer retinal layers (P=0.042). Conclusions In macular hole surgery, structure analysis in OCT is one of the important outcomes for the retinal surgeon. Functional results are parallel with anatomic results, but visual gain is limited. The limited recovery in mfERG suggests an alteration of retinal physiology that could explain limited vision recover.

Psychophysical assessment of koniocellular pathway in patients with schizophrenia versus healthy controls

This study was designed to perform psychophysical assessment of koniocellular pathway in patients with schizophrenia versus healthy controls. A total of 26 patients diagnosed with schizophrenia and 15 healthy controls were included. Snellen Visual Acuity Chart scores and Short Wavelength Automated Perimetry (SWAP) visual field testing including global visual field indices [mean deviation (MD), pattern standard deviation (PSD), test time (min)], reliability parameters [false negative responses (%), false positive responses (%) and fixed losses (%)] and average threshold sensitivity [central (parafovea), peripheral area, and four quadrants] were recorded in both groups. Significantly lower MD scores, higher PSD scores and lower average threshold sensitivity at each location across the visual field were noted in schizophrenia relative to control group. In conclusion, our findings revealed a deficit in koniocellular pathway with impaired SWAP global indices and lower threshold sensitivity at each location across the visual field among chronic schizophrenic patients as compared with control subjects. Our findings emphasize potential application of SWAP outside its original intended purpose as a glaucoma test, to provide deeper understanding of the specific contribution of lateral geniculate nucleus to the visual and cognitive disturbances of schizophrenia.

Prevalence and associated factors of myopia among high school students in Gondar town, northwest Ethiopia, 2016.

IntroductionMyopia is an important cause of correctable visual impairment and preventable blindness worldwide. Prevalence rates are approximately 20%–35% among the older teenage population globally. It has a medical burden of pathologic complications such as maculopathy and glaucomatous optic neuropathy. High school students experience high-performance and study pressures in the preparation for the final national examination. As a result they are exposed to excessive near work and indoor activities. They are also ignored for regular screening.ObjectiveTo determine the prevalence and associated factors of myopia among high school students in Gondar town, Ethiopia.MethodsAn institution-based cross-sectional study was conducted on 498 high school students with systematic random sampling method from April 18 to April 29, 2016, in three full-cycle high schools (9th–12th grades). A standardized structured questionnaire, Snellen acuity chart, pinhole, retinoscope, trial case lenses, pen torch, and direct ophthalmoscope were used to collect data.ResultsA total of 495 study participants were included, and they had a mean age of 17.48±1.59 years. The prevalence of myopia was 11.9% (95% confidence interval [CI]: 10.2, 17.9). Family history of myopia (adjusted odds ratio [AOR]=8.08 [95% CI: 4.30, 15.16]), school being private (AOR=2.88 [95% CI: 1.02, 8.11]), longer time spent for near work (AOR=2.89 [95% CI: 1.12, 7.43]), longer time spent partaking in indoor activities (AOR=4.32 [95% CI: 1.69, 10.99]), shorter near working distance (AOR=3.06 [95% CI: 1.33, 7.06]), lack of outdoor sport activities (AOR=2.27 [95% CI: 1.05, 4.90]), use of visual display units (AOR=2.81 [95% CI: 1.30, 6.10]), and abnormal ocular findings (AOR=6.69 [CI: 3.43, 13.03]) were found to be independently associated with myopia.ConclusionThe prevalence of myopia was 11.9%. Family history for myopia, school being private, longer time spent partaking in indoor activities, shorter working distance, lack of outdoor sport activities, use of visual display units, and presence of abnormal ocular findings were positively associated with myopia.

Measuring the Influence of Galilean Loupe System on Near Visual Acuity of Dentists under Simulated Clinical Conditions.

The purpose of this study was to compare near visual acuity of dentists without optical aids (VSC) with near visual acuity of those using the Galilean telescope system (VGA2) with magnification of x 2.5, and the distance of 350 mm in simulated clinical conditions. The study included 46 dentists (visual acuity 1.0 without correction). A visual acuity testing was carried out using a miniaturized Snellen visual acuity chart which was placed in the cavity of molar teeth mounted in a phantom head in simulated clinical conditions. Near visual acuity for the vicinity was examined: 1) without correction at a distance of 300-400 mm (VSC); 2) with Galilean loupes with magnification of x2.5, focal length of 350mm. The distributions of near visual acuity recorded using VSC and VGA2, 5 systems were compared by the Wilcoxon Signed Rank test. The results obtained by Wilcoxon Signed Rank test pointed to a statistically significant difference in the distribution of recorded visual acuity between the VSC and VGA2 optical systems (W = - 403.5; p <0.001). If using the VGA2, 5 systems, higher values of the near visual acuity were recorded and subsequently compared to near visual acuity without magnifying aids (VSC).

Outcome of 2cc pure sulfur hexafluoride gas tamponade for macular hole surgery.

BackgroundIsoexpansile concentrations of intraocular gases are typically used as tamponading agent in macular hole surgery. Using a small volume of the pure form of these gases may achieve the same result without increasing the incidence of postoperative complications. The purpose of this study was to evaluate the anatomical and visual outcomes following macular hole surgery with 2 cc pure (100 %) sulfur hexafluoride (SF6) gas tamponade.MethodsA retrospective study of eyes with idiopathic macular holes that underwent 23-gauge pars plana vitrectomy with 2 cc pure SF6 gas tamponade. Macular hole surgery was performed alone or in combination with phacoemulsification in eyes with cataract. Preoperative and postoperative data including best corrected visual acuity recorded in LogMAR units, slit-lamp biomicroscopy, and optical coherence tomography were analysed. Surgical complications were also recorded.ResultsSeventy six eyes of seventy five patients were analysed. A closure rate of 100 % was achieved with reoperation in 4 eyes. There was a significant improvement in best-corrected visual acuity from a mean of 0.65 LogMAR preoperatively to 0.36 at 6 months (p value 0.004). Forty five (59 %) eyes gained at least 2 lines on the Snellen visual acuity chart. Postoperative elevation in intraocular pressure (≥30 mmHg) was documented in 3 eyes (4 %).ConclusionMacular hole surgery with 2 cc pure SF6 gas tamponade achieved a high success rate with a low incidence of complications. The smaller volume of gas required makes it a cheaper technique.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-016-0254-9) contains supplementary material, which is available to authorized users.