OBJECTIVES: To analyze the Nogo-P3 component of event-related potential (ERP) in the process of visual acuity processing, to provide electrophysiological evidence for objective evaluation of visual acuity. METHODS: Twenty-six subjects with no other ocular diseases except for ametropia were recruited, and all subjects had uncorrected visual acuity both eyes 1/10 (evaluated using Monoyer chart). Block letter E with different visual angles and directions were used as graphic stimuli. The Go/Nogo paradigm was used for ERP studies. The visual angle of Go stimulation angle was 1°15', Nogo stimuli were 1°15', 55', 24' and 15'. The visual acuity test was performed on each of the two naked eyes separately in all subjects, and the characteristics of the Nogo-P3 component were analyzed. RESULTS: The latency of Nogo-P3 showed no difference between the stimuli of 1°15' and 55', and between Nogo stimulation angle 24' and 15'. There was significant difference between Nogo stimulation angle 1°15' and 24', and between Nogo stimulation angle 1°15' and 15' (P<0.05). There was significant difference between Nogo stimulation angle 55' and 24', and between Nogo stimulation angle 55' and 15' (P<0.05). No significant differences were observed in the Nogo-P3 amplitude among Nogo stimulation. CONCLUSIONS In the Go/Nogo paradigm, Nogo-P3 can reflect the cognitive response of subjects to Nogo stimulation, which can be used for objective evaluation of visual acuity.
Electroencephalography ; Evoked Potentials/physiology* ; Humans ; Photic Stimulation ; Reaction Time/physiology* ; Refractive Errors ; Visual Acuity

BACKGROUND: Herpes virus is considered to be the pathogen of acute retinal necrosis (ARN) infection. Previous studies have found that patients with ARN caused by the varicella-zoster virus (VZV) are often older, and patients with herpes simplex virus (HSV) induced ARN are considerably younger. However, in our clinical work, we find that VZV is also a pathogen in younger ARN patients. We, therefore, aimed to analyze the common etiology of younger ARN patients. METHODS: A retrospective analysis was made of 20 eyes (18 patients) diagnosed as having ARN in the Department of Ophthalmology of Peking Union Medical College Hospital from 2014 to 2016. All patients were reviewed for demographic data, clinical course, clinical manifestations, time from onset to initial physician visit, duration of follow-up, visual acuity at both presentation and final visit, and treatment strategies. A paired t test was used to compare visual acuity between the presenting vision and those of final follow-up. Vitreous or aqueous specimens from 18 eyes of 18 patients were analyzed with multiplex polymerase chain reaction (mPCR)/quantitative PCR (qPCR) and xTAG-liquid chip technology (xTAG-LCT) to determine the causative virus of ARN. RESULTS: Final best visual acuity (BCVA) improved significantly from 1.36 ± 0.95 (median 20/400) to 0.95 ± 0.82 (median 20/100) (t = 2.714, P = 0.015) after systemic and intravitreal antiviral treatment combined with or without pars plana vitrectomy. PCR and xTAG-LCT results showed four of the five samples in the younger group (32.2 ± 5.2 years) and 12 of the 13 samples in the senior group (53.6 ± 4.9 years) were positive for VZV, and two of the five samples in the younger group were positive for HSV-1. CONCLUSIONS This study demonstrates that VZV is also a common causative virus for ARN in younger patients. Considering this finding, a systemic antiviral treatment protocol should be immediately changed to intravenous ganciclovir when the patient does not respond to acyclovir before determining the causative virus, especially in younger patients.
Adult ; Age Factors ; Female ; Herpesvirus 3, Human ; pathogenicity ; Humans ; Male ; Middle Aged ; Retinal Necrosis Syndrome, Acute ; etiology ; physiopathology ; virology ; Retrospective Studies ; Varicella Zoster Virus Infection ; complications ; Visual Acuity ; physiology

The process of reading words depends heavily on efficient visual skills, including analyzing and decomposing basic visual features. Surprisingly, previous reading-related studies have almost exclusively focused on gross aspects of visual skills, while only very few have investigated the role of finer skills. The present study filled this gap and examined the relations of two finer visual skills measured by grating acuity (the ability to resolve periodic luminance variations across space) and Vernier acuity (the ability to detect/discriminate relative locations of features) to Chinese character-processing as measured by character form-matching and lexical decision tasks in skilled adult readers. The results showed that Vernier acuity was significantly correlated with performance in character form-matching but not visual symbol form-matching, while no correlation was found between grating acuity and character processing. Interestingly, we found no correlation of the two visual skills with lexical decision performance. These findings provide for the first time empirical evidence that the finer visual skills, particularly as reflected in Vernier acuity, may directly contribute to an early stage of hierarchical word processing.
Adolescent ; Decision Making ; Female ; Form Perception ; physiology ; Humans ; Male ; Pattern Recognition, Visual ; physiology ; Photic Stimulation ; Reading ; Semantics ; Statistics as Topic ; Visual Acuity ; physiology ; Vocabulary ; Young Adult

OBJECTIVES: To explore the composition characteristic of event related potential （ERP） in different visual acuity levels, and to provide theoretical basis for the objective assessment of visual acuity. METHODS: Monocular stimulus was performed on 16 selected subjects. The subjects were required to look straight at the screen ahead and count the amount of stimuli from different directions. The pictures of optotype stimulus which corresponding to three different visual acuity levels were showed in the center of the screen. The ERP results were recorded separately. RESULTS: （1） The P₁ amplitudes of match stimuli recorded under the supra-threshold visual acuity level were higher than that of match stimuli recorded under the threshold and sub-threshold visual acuity levels. There was no significant difference between the P₁ amplitudes of match stimuli recorded under the threshold and sub-threshold visual acuity levels. The tendency of conflict stimuli was similar to that of match stimuli under three visual acuity levels. （2） In the 340-500 ms post-stimulus range, P₃₀₀ component was found under supra-threshold and threshold visual acuity levels; no P₃₀₀ component was found in corresponding time window under sub-threshold visual acuity. The differences of P₃₀₀ amplitudes among three visual acuity levels were statistically significant. The amplitudes from high to low were the supra-threshold, threshold and sub-threshold visual acuity levels. CONCLUSIONS ERP can be a potential new method for the objective assessment of visual acuity in forensic medicine.
Adult ; Evoked Potentials ; Evoked Potentials, Visual ; Humans ; Photic Stimulation ; Visual Acuity/physiology* ; Visual Perception

OBJECTIVES: To study the characteristic of contrast visual evoked potentials （CVEP） in patients with ocular trauma. METHODS: Sixty patients defined as ocular trauma by forensic clinical examination in our center were selected, and split into 0.2-0.3 （Group A）, 0.3-0.5 （Group B） and ≥0.5 （Group C） according to the best corrected visual acuity. The variation characteristics of wave amplitude and latency of CVEP under 100%, 25% and 10% contrast were observed and analyzed statistically. RESULTS: （1） Under the same contrast, the wave amplitude of P₁₀₀ decreased with the decrease of stimulus perspective. （2） Under the same stimulus perspective, the wave amplitude of P₁₀₀ decreased with the decrease of contrast （P<0.05）. （3） Under the contrast of 100% and 25% with the same stimulus perspective （except 100% 7' perspective stimulus）, the difference between group A and group B had no statistical significance （P>0.05）. Between group A and group C, group B and group C, the wave amplitude of P₁₀₀ gradually increased with the increase of vision （P<0.05）. Under the contrast of 10% with 15' stimulus perspective, the wave amplitude of P₁₀₀ increased with the increase of vision （P<0.05）. （4） Under the same contrast with the same stimulation perspective, the latency of P₁₀₀ wave shortened with the increase of vision, while the difference had no statistical significance （P>0.05）. Under the same stimulus perspective, the latency of P₁₀₀ wave was prolonged with the decrease of contrast （P>0.05）. CONCLUSIONS CVEP may become one of the possible methods for the evaluation of contrast visual acuity.
Evoked Potentials, Visual/physiology* ; Eye Injuries/physiopathology* ; Humans ; Pattern Recognition, Visual/physiology* ; Photic Stimulation ; Vision, Ocular ; Visual Acuity

OBJECTIVES: To study the effect of different attentional conditions on the event-related potential （ERP） components generated by the visual information stimuli related to visual acuity, and provide a theoretical reference for clinical forensic visual objective evaluation. METHODS: With visual acuity optotypes as normal form of visual information stimuli, 15 volunteers as study subjects were supposed to account the visual acuity optotypes under the attentional condition of visual stimuli. Furthermore, the subjects were required to listen to the storytelling carefully under the non-attentional condition of visual stimuli, and after the examination, they needed to answer the story-related questions. All the EEG results of two different attentional conditions from the subjects were recorded by 32 channel ERP system. RESULTS: Under two attentional conditions, P₁ and P₃₀₀ components were evoked by the visual acuity optotypes on supra-threshold and threshold visual acuity levels, while only P₁ component were evoked by the visual acuity optotypes on sub-threshold levels. In the ERP waveforms evoked by the visual acuity optotypes on supra-threshold, P₁ and P₃₀₀ amplitudes under attentional condition were larger than that under non-attentional condition. CONCLUSIONS Attentional conditions can influence the detection of visual acuity. P₃₀₀ component can be used to distinguish the visual acuity levels with supra-threshold and sub-threshold under non-attentional condition.
Attention/physiology* ; Electroencephalography ; Evoked Potentials ; Evoked Potentials, Visual ; Humans ; Visual Acuity

PURPOSE: Our study provides epidemiologic data on the prevalence of refractive errors in all age group ≥5 years in Korea. METHODS: In 2008 to 2012, a total of 33,355 participants aged ≥5 years underwent ophthalmologic examinations. Using the right eye, myopia was defined as a spherical equivalent (SE) less than -0.5 or -1.0 diopters (D) in subjects aged 19 years and older or as an SE less than -0.75 or -1.25 D in subjects aged 5 to 18 years according to non-cycloplegic refraction. Other refractive errors were defined as follows: high myopia as an SE less than -6.0 D; hyperopia as an SE larger than +0.5 D; and astigmatism as a cylindrical error less than -1.0 D. The prevalence and risk factors of myopia were evaluated. RESULTS: Prevalence rates with a 95% confidence interval were determined for myopia (SE <-0.5 D, 51.9% [51.2 to 52.7]; SE <-1.0 D, 39.6% [38.8 to 40.3]), high myopia (5.0% [4.7 to 5.3]), hyperopia (13.4% [12.9 to 13.9]), and astigmatism (31.2% [30.5 to 32.0]). The prevalence of myopia demonstrated a nonlinear distribution with the highest peak between the ages of 19 and 29 years. The prevalence of hyperopia decreased with age in subjects aged 39 years or younger and then increased with age in subjects aged 40 years or older. The prevalence of astigmatism gradually increased with age. Education was associated with all refractive errors; myopia was more prevalent and hyperopia and astigmatism were less prevalent in the highly educated groups. CONCLUSIONS: In young generations, the prevalence of myopia in Korea was much higher compared to the white or black populations in Western countries and is consistent with the high prevalence found in most other Asian countries. The overall prevalence of hyperopia was much lower compared to that of the white Western population. Age and education level were significant predictive factors associated with all kinds of refractive errors.
Adolescent ; Adult ; Age Distribution ; Aged ; Child ; Child, Preschool ; Cross-Sectional Studies ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; *Nutrition Surveys ; Prevalence ; Refractive Errors/*epidemiology/physiopathology ; Republic of Korea/epidemiology ; Retrospective Studies ; Risk Factors ; Visual Acuity/*physiology ; Young Adult

BACKGROUNDPolypoidal choroidal vasculopathy (PCV) is characterized by the presence of polyps with or without a branching vascular network and more prevalent among Asians. The aim of this study was to compare the outcomes of conbercept therapy between two different angiographic subtypes of PCV.

METHODSFifty-eight patients of PCV were classified into two phenotypes according to indocyanine green angiography (ICGA). In Type 1, both feeder and draining vessels are visible on ICGA and network vessels are numerous. In Type 2, neither feeder nor draining vessels are detectable, and the number of network vessels is small. The patients were treated with intravitreal conbercept (IVC) for 3 months. Additional IVC was given at subsequent monthly visits, if needed. The patients were followed up for 12 months, and changes in mean best-corrected visual acuity (BCVA), central retinal thickness (CRT), subretinal fluid (SRF) thickness, pigmented epithelial detachment (PED), hemorrhage, and number of polypoidal lesions were evaluated.

RESULTSThe mean BCVA in Type 2 PCV (15.92 ± 9.76 letters) achieved a significantly greater improvement than that in the Type 1 (14.10 ± 9.07 letters) at month 12 (t = 2.37, P< 0.01). Moreover, the mean CRT decrease was numerically greater in Type 2 (120.44 ± 73.81 μm) compared with Type 1 (106.48 ± 72.33 μm) at month 6 (t = 4.31, P< 0.01), and greater in Type 2 (130.21 ± 76.28 μm) compared with Type 1 (111.67 ± 79.57 μm) at month 9 (t = 1.87, P< 0.01). There was no significant difference between the two types for the decrease in SRF thickness, PED height, and regression of polyps from month 3 to 12 (t = 2.97, P > 0.05).

CONCLUSIONClassification systems for PCV will show differences in presentation, natural history, or response to anti-vascular endothelial growth factor treatment and might, therefore, provide a new key to the choice of treatment for the disease.

Aged ; Choroid ; physiopathology ; surgery ; Choroidal Neovascularization ; physiopathology ; surgery ; Female ; Humans ; Male ; Middle Aged ; Postoperative Care ; Retrospective Studies ; Treatment Outcome ; Visual Acuity ; physiology

BACKGROUNDSmall incision refractive lenticule extraction (SMILE) is an effective laser procedure that treats myopia. This research was to describe a novel approach to treat corneal ulcer or perforation using the corneal lenticules obtained from SMILE and to evaluate the safety and effectiveness of tectonic keratoplasty with femtosecond laser intrastromal lenticule (TEKIL).

METHODSA total of twenty patients (22 eyes) were monitored for at least 6 months and were assessed using slit lamp microscopy, optical coherence tomography, and best-corrected visual acuity (BCVA). Postoperative complications throughout the study period were recorded.

RESULTSCorneal ulcer in 14 patients (16 eyes) and corneal perforation in six patients (6 eyes) were treated with TEKIL. The patients were ten females and ten males, with a mean age of 58.5 ± 16.3 years (range: 16-81 years). In this study, the most causes of corneal ulcer or perforation were immunologic causes (54.5%). After TEKIL procedure, global integrity was achieved in all cases. No immune rejection or perforation was detected. The mean BCVA improved from 0.17 ± 0.20 preoperatively to 0.27 ± 0.25 postoperatively at the final follow-up (t = 2.095, P = 0.052). The postoperative BCVA improved in 12 eyes (54.5%) and maintained in nine eyes (40.9%). Vision function successfully maintained in all eyes (100%). In three cases, corneal ulcers were treated by reoperation of TEKIL at 3 months after the initial surgery for the reason that the residual corneal thickness was <250 μm.

CONCLUSIONSTEKIL seems to be an effective treatment for corneal ulcer and perforation in the condition of emergency and donor shortage.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cornea ; surgery ; Corneal Perforation ; physiopathology ; surgery ; Corneal Transplantation ; adverse effects ; methods ; Corneal Ulcer ; physiopathology ; surgery ; Female ; Humans ; Male ; Middle Aged ; Postoperative Complications ; Retrospective Studies ; Tomography, Optical Coherence ; Visual Acuity ; physiology ; Young Adult

PURPOSE: To investigate the long-term clinical course of intermittent exotropia after surgical treatment to determine whether and when postoperative exo-drift stabilizes, and the required postsurgery follow-up duration in cases of intermittent exotropia. METHODS: We retrospectively reviewed the medical records of patients diagnosed with intermittent exotropia who underwent surgical treatment between January 1992 and January 2006 at Yeungnam University Hospital and postoperatively performed regular follow-up examinations for up to 7 years. We also analyzed the difference in exo-drift stabilization, according to surgical procedure. RESULTS: A total of 101 patients were enrolled in the study. Thirty-one patients underwent lateral rectus recession and medial rectus resection (R&R) and 70 patients underwent bilateral lateral rectus recession (BLR). The postoperative angles of deviation increased significantly during the initial 36 months, but no subsequent significant changes were observed for up to 84 months. Follow-ups for 7 years revealed that more than 50% of the total amount of exo-drift was observed within the first postoperative year. In addition, the angles of deviation at 1 year correlated with those at 7 years postoperatively (Pearson correlation coefficient r = 0.517, p < 0.001). No significant exo-drift was observed after 36 months in patients who underwent BLR, whereas after 18 months in patients who underwent R&R. CONCLUSIONS: The minimum postoperative follow-up required after surgical treatment to ensure stable results is 36 months. In particular, careful follow-up is necessary during the first postoperative year to detect rapid exo-drift. Patients who underwent BLR required a longer follow-up than those who underwent R&R to ensure stable postoperative alignment.
Child ; Child, Preschool ; Exotropia/*physiopathology/surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/*physiopathology/surgery ; *Ophthalmologic Surgical Procedures ; Postoperative Complications/*physiopathology ; Retrospective Studies ; Vision, Binocular/physiology ; Visual Acuity/physiology