Worse Uncorrected Visual Acuity Research Articles

The spike of acute angle closure after the epidemic downgrade of COVID-19 management: a hospital-based comparative study from China.

To analyse and compare the clinical characteristics and treatment outcomes of patients with acute angle closure (AAC) who presented before the COVID-19 pandemic, during the COVID-19 management and after their downgrading. Consecutive AAC patients were recruited from our hospital and divided into three groups: those treated before the COVID-19 pandemic (Group1), during the COVID-19 management (Group2) and after the management downgrade (Group3). The demographic variables, clinical characteristics, treatment methods and therapeutic outcomes of the groups were compared. When compared to Groups1 and 2, Group3 showed a significantly higher incidence of AAC (0.27%, P < 0.001), a longer time from symptoms to treatment (TST; 160.88 ± 137.05h, P = 0.031) and worse uncorrected visual acuity (P = 0.009) at presentation. In Group3, 68.9% had a history of COVID-19 and 28.5% developed ocular symptoms of AAC after taking medication for COVID-19 symptoms. The average time from the onset of COVID-19 to the appearance of eye symptoms was 3.21 ± 4.00days. The COVID-19 has had a multifaceted impact on the incidence of AAC. Therefore, it is crucial to strengthen health education on glaucoma, especially AAC. The prevention and timely treatment of AAC should be emphasised to combat global blindness.

Visual impairment and spectacles ownership among upper secondary school students in northwestern China

To assess the prevalence of visual impairment and spectacles ownership among academic and vocational upper secondary school students in rural China. This cross-sectional study included 5583 students from four academic upper secondary schools (AUSSs) and two vocational upper secondary schools (VUSSs) in Mei and Qianyang counties, Baoji Prefecture, Shaanxi Province. In March and April 2016, students underwent assessment of visual acuity (VA) and completed a questionnaire regarding spectacles use and family characteristics. Students with visual impairment (presenting VA ≤6/12 in the better eye) and students needing spectacles (uncorrected VA ≤6/12 in the better eye, which could be improved to >6/12 with refraction) were identified. Among 5583 students (54% boys, mean age 16.4±1.0 years) in grades 10 and grade 11 attending AUSSs (n=4549) and VUSSs (n=1034), visual impairment was detected in 4026 students. Among the AUSS students, 3425 (75%) needed spectacles; 2551 (75%) had them. Among the VUSS students, 601 (58%) needed spectacles; this proportion was significantly smaller (P=0.004), as was the proportion who had spectacles (n=212, 35%, P<0.001), compared with the AUSS students. Multivariate analysis showed that ownership of spectacles among children who needed them was associated with worse uncorrected VA (P<0.001), male sex (P<0.001), and residence in an urban area (P<0.034). Spectacles ownership was also strongly associated with AUSS education (P<0.001). There is a high rate of unmet need in visual care among upper secondary school students. Lack of spectacles ownership among children who needed them was significantly associated with VUSS education.

Prevalence and characteristics of peripheral myopic retinopathy in Guangzhou office workers.

To determine the prevalence and characteristics of peripheral myopic retinopathy among a sample of Guangzhou office workers. A cross-sectional study of Guangzhou Chinese office works in different departments and units of the Guangzhou Power Supply Bureau, China, in 2016. Myopic retinopathy was recorded and analyzed with a scanning laser ophthalmoscope and by slit-lamp microscopy combined with a three-mirror contact lens. In total, 1910 eyes of 955 subjects (508 females and 447 males) aged 21-59y were included; 69.6% of these eyes were myopic. The myopia group had a younger age and worse uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) when compared with hyperopia and emmetropia groups (P<0.001). The axial length (AL) was significantly longer, the spherical equivalent (SE) was more serious, and the optic nerve crescent was significantly larger in subjects with myopia than with hyperopia and emmetropia. Subjects with myopia, and especially high myopia, had the highest frequency of myopic retinal 18 changes (49.4%, P<0.001) [white-without-pressure (43.8%, P<0.001), lattice degeneration (4.5%, P=0.044)] among the three groups. Logistic regression confirmed that any myopia (OR: 3.41, P<0.001) [mild myopia (OR: 1.93, P=0.001), moderate myopia (OR:3.64, P<0.001), and high myopia (OR:10.58, P<0.001)], a greater AL (OR: 1.55, P<0.001) and a much higher SE (OR: 0.77, P<0.001) increased the risk for peripheral retinal changes. Myopia-related retinal changes are positively associated with greater AL, higher SE, and myopia.

Interocular Axial Length and Corneal Power Differences as Predictors of Postoperative Refractive Outcomes after Cataract Surgery

To determine whether differences between eyes in axial length (AL) and corneal power (K) on optical biometry are predictive of refractive outcomes. Retrospective cohort study. A total of 729 patients (1458 eyes) who underwent bilateral phacoemulsification at TLC (Mississauga, Ontario, Canada) from September 2013 to August2015. We compared the proportion of patients having >0.5 diopters (D) of refractive error from target stratified by interocular axial length differences (IALDs) and interocular K differences (IKDs) between eyes as measured by optical biometry (IOL-Master, Carl Zeiss Meditec, Oberkochen, Germany). Analysis was repeated for 0.25 D or 1.0 D targets and for patients with uncorrected visual acuity (UCVA) >0.3 logarithm of the minimum angle of resolution (logMAR) postoperatively. Proportions, odds ratios (ORs), and corresponding 95% confidence intervals (CIs) were computed using generalized estimating equations to account for within-patient correlation. Some 79.1% of eyes were ≤0.5 D of refractive target, 47.0% were ≤0.25 D, and 97.2% were ≤1.0 D. The OR of having a refractive outcome >0.5 D from target for IALD cutoff of 0.2 mm was 1.4 (1.1-1.8), of 0.3 mm was 1.6 (1.2-2.1), and of 0.4 mm was 1.8 (1.3-2.5). This translates to 70.0% (63.5-75.7) within target for IALD of ≥0.4 mm versus 80.7% (78.4-82.9) for <0.4 mm. For a given patient with IALD, the chance of being off target was similar for the shorter and longer eye. Eyes outside of target were twice as likely to be <-0.5 D than >0.5 D. Interocular K difference was largely not associated with prediction error, yet larger IKD-flat, steep, and average were associated with increased odds of UCVA >0.3 logMAR postoperatively. Interocular axial length difference of as little as ≥0.2 mm is associated with a higher chance of >0.5 D of refractive error from target and worse UCVA. Interocular K difference was not associated with worse refractive error from target, although a difference of ≥0.4 D was associated with worse UCVA. These cutoffs should be considered in preoperative planning and discussion with patients. Future study is required to assess whether repeating measurements, using adjunctive measurement devices, or attempting to separate true differences from artifact based on preoperative refractive characteristics reduces residual refractive error.

Randomized, Controlled Trial of an Educational Intervention to Promote Spectacle Use in Rural China: The See Well to Learn Well Study

To test an educational intervention promoting the purchase of spectacles among Chinese children. Randomized, controlled trial. Children in years 1 and 2 of all 20 junior and senior high schools (ages 12-17 years) in 3 rural townships in Guangdong, China. Children underwent visual acuity (VA) testing, and parents of participants with presenting VA worse than 6/12 in either eye improving by more than 2 lines with cycloplegic refraction were recommended to purchase glasses. Children at 10 randomly selected schools received a lecture, video, and classroom demonstration promoting spectacle purchase. Self-reported purchase of spectacles (primary outcome) and observed wear or possession of newly purchased glasses (secondary outcome) at follow-up examinations (mean, 219 ± 87 days after the baseline visit). Among 15 404 eligible children, examinations were completed for 6379 (74.6%) at intervention schools and 5044 (73.6%) at control schools. Spectacles were recommended for 2236 (35.1%) children at intervention schools and for 2212 (43.9%) at control schools. Of these, 417 (25.7%) intervention schools children and 537 (34.0%, P = 0.45) control schools children reported buying glasses. Predictors of purchase in regression models included female gender (P = 0.02), worse uncorrected VA (P < 0.001), and higher absolute value of refractive error (P = 0.001). Neither the rate of self-reported purchase of glasses or observed wear or possession of newly purchased glasses differed between control schools and intervention schools in mixed-effect logistic regression models. Among children not purchasing glasses, 21.7% had better-eye VA of worse than 6/18. An intervention based on extensive pilot testing and focus groups in the area failed to promote spectacle purchase or wear. The high burden of remaining uncorrected poor vision underscores the need to develop better interventions. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Relationship between preoperative aberrations and postoperative refractive error in enhancement of previous laser in situ keratomileusis with the LADARVision system

To identify factors leading to inaccuracy of spherical correction in wavefront-guided enhancement treatments. Department of Ophthalmology, University of California, Irvine, California, USA. This retrospective outcomes analysis comprised 23 eyes (20 patients) having wavefront-guided flap-lift (19 eyes) or photorefractive keratectomy (4 eyes) enhancements after conventional non-wavefront-guided laser in situ keratomileusis (LASIK) for correction of residual myopia with a minimum follow-up of 1 month. Main outcomes measures were changes in lower-order aberrations and higher-order aberrations (HOAs) related to predictability of the refractive outcome. The enhancement procedures reduced HOAs. Because of a hyperopic shift, however, uncorrected visual acuity (UCVA) improved 2 or more Snellen lines in 3 of 9 eyes (33.3%) treated without a surgeon offset compared with 9 of 14 (64.3%) when a surgeon offset was incorporated into the treatment plan. The quantitative amount of preoperative HOAs correlated with the amount of hyperopic shift, particularly strongly for spherical aberration (r(2) = 0.446, P = .0005). The amount of hyperopic shift was related in a linear manner to the amount of HOAs (for spherical aberrations, Y = 1.31X - 0.30, where Y is the postoperative manifest refraction spherical equivalent and X is the wavefront error in microns root mean square). Wavefront-guided enhancements can reduce levels of HOAs. Although UCVA improved in many patients, some with high levels of preenhancement spherical aberration had worse UCVA. Adjusting the nomogram for the amount of preenhancement HOAs may improve the accuracy of the lower-order correction in wavefront-guided enhancements.

Effect of methods of myopia correction on visual acuity, contrast sensitivity, and depth of focus

Purpose: To psychophysically measure spherical and irregular aberrations in patients with various types of myopia correction. Setting: Laboratory of Experimental Ophthalmology, University of Groningen, Groningen, The Netherlands. Methods: Three groups of patients with low myopia correction (spectacles, soft contact lens, and Intacs) and 4 groups with high myopia correction (spectacles, rigid contact lens, Artisan claw lens, and laser in situ keratomileusis [LASIK]) had through-focus contrast sensitivity measurements to establish the myopic shift and depth of focus. From these 2 parameters, spherical and irregular aberrations were determined using theoretical eye models and geometric optics. Visual acuity, stray light, and predictability were also studied. Results: There were no differences in best corrected visual acuity (BCVA) or best corrected contrast sensitivity between the low myopia groups. The Intacs group had a significantly larger depth of focus ( P<.05). The results in the soft contact lens group were comparable to those in a human eye model with an average amount of spherical and irregular aberrations. The LASIK group had worse uncorrected visual acuity (UCVA) and best corrected contrast sensitivity than the spectacles, rigid contact lens, and Artisan claw lens groups ( P<.05) due to the amount of spherical and irregular aberrations present after LASIK. The low and high myopia spectacles groups had average amounts of spherical and irregular aberrations. Conclusions: Neither surgical techniques nor contact lenses resulted in BCVA or best corrected contrast sensitivity that surpassed the values measured in the best corrected spectacles groups. The Artisan claw lens performed better than LASIK in UCVA, predictability, and best corrected contrast sensitivity.

Ten-year Refractive and Visual Results of Radial Keratotomy

Purpose: The authors evaluated the 10-year refractive and visual acuity results of a cohort of patients who underwent radial keratotomy (RK).Methods: A prospective cohort study was begun in 1980 of 198 consecutive myopic eyes of patients who were to undergo RK surgery. Patients were at least 18 years of age with myopia between 1.75 and 10 diopters. All patients signed consent forms. Refraction, uncorrected visual acuity (UVA), and best corrected visual acuity (BCVA) were the main outcomes evaluated at 10 years.Results: Mean refraction at 10 years was -0.12 D, compared with -0.43 D at 5 years. Fifty-seven percent of eyes had UVA of at least 20/40 at 10 years, compared with 55% at 5 years. Improvement in UVA between 5 and 10 years occurred most frequently in eyes with most preoperative myopia and most surgery. Eighty-five percent of eyes had BCVA of at least 20/25 at 10 years, compared with 81 % at 5 years. Women had significantly less myopia then men before surgery (P< 0.01), yet had similar UVA and worse BCVA. At 10 years, women had similar refraction but worse UVA and BCVA than men.Conclusions: Radial keratotomy was shown to be effective 10 years later. Some refractive and acuity changes occurred between 5 and 10 years' follow-up, but these were mainly normal physiologic changes that occur with aging. Women had poorer vision than men before RK surgery and less beneficial results after surgery.