The effectiveness of laser vitreolysis for vitreous floaters in posterior vitreous detachment

Purpose: To determine the effectiveness of laser vitreolysis in terms of contrast sensitivity function (CSF) and vision?related quality of life (VRQol) for symptomatic floaters due to posterior vitreous detachment (PVD). Materials: This is an interventional study that involved 57 eyes of 45 patients with symptomatic floaters for more than 3 months. Patients underwent one to three sessions of vitreolysis via Neodymiun?doped Yttrium Aluminum Garnet (Nd:YAG) laser. We examined the CSF using the computer programs Freiburg Acuity and Contrast Test (FrACT) and VRQoL survey using the National Eye Institute Visual Function Questionnaire?25 (NEI VFQ?25) before, and 1 month after, vitreolysis. Results: Twelve patients had both eyes lasered and 33 patients had one eye lasered. The mean CSF improved from 3.20 ± 0.85%W to 2.64 ± 0.63%W 1 month after vitreolysis. Each use of the laser showed a significant mean difference in CSF (%W) as analyzed by paired t?test before and after the first laser (0.29 ± 0.49%W [P ? 0.001]); after the first and second laser (0.35 ± 0.53%W [P = 0.01]); and after second and third laser (0.21 ± 0.31%W [P = 0.02]). There was improvement in the median of four subscales in NEI VFQ?25 scores post treatment: general vision (z = ?3.30, P = 0.001), near activity (z = 3.396, P = 0.001, distance activity (z = ?2.788, P = 0.005), and mental health (z = ?2.219, P = 0.026). The mean scores increased to 79.55 ± 9.45 from the baseline 75.06 ± 9.69 (P ? 0.001). No adverse events were recorded 1 month after the laser treatments. Conclusion: Vitreolysis by Nd:YAG laser improved the CFS and VRQoL in symptomatic PVD patients.

Sensibilidad al contraste en edad pediátrica / Contrast sensitivity in pediatric ages

La sensibilidad al contraste es considerada como la capacidad de discriminar diferencias de iluminación entre áreas adyacentes, cuyo umbral se estima como la menor cantidad de contraste que se necesita para lograr esta distinción. La medida de la agudeza visual cuantifica la visión en alto contraste; sin embargo, los objetos que nos encontramos en la vida real no son solo de alto contraste, sino que presentan diferentes niveles de contraste y tamaño, lo cual puede ser determinado con el estudio de la sensibilidad al contraste, ya sea a través de cartillas de bajo contraste o de las pruebas que evalúan las frecuencias espaciales, que serán utilizadas según la edad del paciente pediátrico. Con este trabajo se pretende mostrar los diferentes criterios relacionados con la sensibilidad al contraste en edades pediátricas, para lo cual se realizó una búsqueda en diferentes publicaciones y textos de la especialidad. Existe controversia relacionada con la edad pediátrica en la cual se alcanza la sensibilidad al contraste al nivel del adulto, así como los valores normativos en la infancia con las diferentes pruebas empleadas. La valoración de la sensibilidad al contraste constituye una herramienta más para evaluar la función visual conjuntamente con la determinación de la agudeza visual y la visión de colores. Se necesitan más estudios sobre este tema para unificar criterios con el fin de perfeccionar la atención a la población pediátrica(AU)

Contrast sensitivity is the ability to distinguish differences in luminance between adjacent areas. Its threshold is estimated as the smallest amount of contrast needed to achieve such a distinction. Visual acuity measurement quantifies high contrast vision. However, the objects around us are not only characterized by high contrast: they display different levels of contrast and size, which may be determined through the study of contrast sensitivity, either with low contrast charts or spatial frequency tests, to be used according to the pediatric patient's age. The purpose of the study was to present various criteria about contrast sensitivity in pediatric ages. To achieve this end, a search was conducted in different publications and texts from the specialty. A debate is currently in progress about the pediatric age in which adult contrast sensitivity is achieved and the standard values to be verified with the different tests applied in childhood. Contrast sensitivity assessment is one more tool to evaluate visual function and determine visual acuity and color vision. Further studies are required about the subject aimed at unifying criteria so as to improve the care of the pediatric population(AU)

Combined influence of illness duration and medication type on visual sensitivity in schizophrenia

Objective: Patients with schizophrenia have visual processing impairments. The main findings from the literature indicate that these deficits may be related to differences in paradigms, medications, and illness duration. This study is part of a large-scale study investigating visual sensitivity in schizophrenia. Here we aimed to investigate the combined effects of illness duration and antipsychotic use on contrast sensitivity function. Methods: Data were collected from 50 healthy controls and 50 outpatients with schizophrenia (classified according to illness duration and medication type) aged 20-45 years old. The contrast sensitivity function was measured for spatial frequencies ranging from 0.2 to 20 cycles per degree using linear sine-wave gratings. Results: Patients with an illness duration > 5 years had more pronounced deficits. Differences in the combined effects of illness duration and antipsychotic use were marked in patients on typical antipsychotics who had been ill > 10 years. No significant differences were found between typical and atypical antipsychotics in patients with an illness duration < 5 years. Conclusion: Visual impairment was related to both long illness duration and medication type. These results should be tested in further studies to investigate pharmacological mechanisms.

Application of the quick contrast sensitivity function in visual function assessment / 中华实验眼科杂志

The contrast sensitivity function (CSF) describes visual sensitivity at different contrasts and spatial scales,which provides a fundamental caracterization of spatial vision,important for basic and clinical applications,but its long testing time has prevented the easy and widespread assessment.The quick contrast sensitivity function (qCSF) method is a novel Bayesian adaptive procedure for rapid measurement of the CSF,which can greatly improve the efficiency of CSF assessment.In the normal eyes,amblyopia,myopia and a low vision population,the high sensitivity,high precision and high test-retest reliability of the qCSF method have been verified.The qCSF method also shows higher CSF efficiency and lower costs in a large sample.Currently,the qCSF method has been implemented on iPad,and medical devices using this program have also been applied in some clinical institutions in the United States and Germany,which has a good prospect in clinical application.In this review,the application of the qCSF in visual function assessment was reviewed.

Comparison of implantable collamer lens implantation and FS-LASIK for moderatetohigh myopia / 眼科新进展

Objective To evaluate and compare the primary clinical efficacy in high myopia patients undergoing implantable collamer lens (ICL) implantation or femtosecond laser-LASIK (FS-LASIK).Methods Totally 73 patients with myopia from August 2016 to March 2017 in our hospital were collected and divided into ICL group(35 patients with 69 eyes) who receiving ICL implantation and LASIK group (38 patients with 76 eyes) who underwent FS-LASIK.There was no significant difference in gender composition and age between the two groups (both P ＞ 0.05).In addition,there was no significant difference in contrast sensitivity function (CSF) and glare CSF (GCSF) between the two groups before operation (both P ＞ 0.05).After 6 months of follow-up,the patient's uncorrected visual acuity,best corrected visual acuity and equivalent spherical degree were detected,and efficacy index and safety index were calculated.Meanwhile,CSF and GCSF examination were performed,followed by the observation of the occurrence of complications.Results There was no significant difference in the uncorrected visual acuity and best corrected visual acuity between the two groups before surgery (all P ＞ 0.05).The preoperative spherical equivalent in the ICL group was -4.000 to-12.00 (-8.86 ±3.70)D,and-4.00 to-11.75 (-8.51 ±4.20)D in the LASIK group,with no statistically significant difference (P ＞ 0.05).There was no significant difference in the uncorrected visual acuity,best corrected visual acuity and spherical equivalent between the two groups after surgery (all P ＞ 0.05).The efficacy coefficient and safety index of the ICL group were better than those in the LASIK group after 6 months,and the differences were statistically significant (all P ＜ 0.05).The CSF in the ICL group was at 1.5 c · d-1,3.0 c · d-1,6.0 c · d 1,12.0 c · d-1,and 18.0 c · d-1 after surgery,which was superior to the LASIK group,and the differences were statistically significant (all P ＜ 0.05).The GCSF in the ICL group was at 1.5 c · d-1,3.0 c · d-1,6.0 c · d-1 and 18.0 c · d-1 after surgery,which was superior to the LASIK group,and the differences were statistically significant (all P ＜ 0.05).Four hours after operation,there were 4 patients (7 eyes) with increased intraocular pressure,which were controlled by anterior chamber puncture,but no lens opacity presented.Conclusion Both ICL and FS-LASIK can effectively correct moderateto highmyopia,but ICL is better than FS-LASIK at the effectiveness index,the safety index,CSF and GCSF.

Effect of the color of the intraocular lens on optical and visual quality.

Purpose: To analyze the optical quality of intraocular lenses (IOL) with an orange (PC440Y) and a yellow (SN60AT) filter, and correlate these results with the visual quality of patients with these implants. Setting: Fisabio Oftalmología Médica, Valencia, Spain. Design: Randomized prospective study. Materials and Methods: The IOL optical quality was determined using the modulation transfer function (MTF) and the spectral transmission. The visual quality of 87 eyes with cataract (51 with orange filter and 36 with yellow filter) was determined by best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions. To analyze the results, we use a Student’s t‑test. Results: Orange lens filtered more of the blue spectrum (cut‑off wavelength of 370 nm) than the yellow lens (390 nm). The MTF of the yellow lens was better than the orange lens (average modulation of 0.676 for natural and 0.672 for orange). The patients’ BCVA was 0.02 + 0.10 logMAR for both lenses. The CSF obtained with the yellow lens was slightly better, although without statistically significant differences (P > 0.05). Conclusions: Both lenses are of good optical quality. The patients’ visual quality was similar with both lenses, and optical quality was also similar. The color of the lens does not affect the visual quality of the patient.

Acute effect of alcohol intake on sine-wave Cartesian and polar contrast sensitivity functions

The aim of this study was to assess contrast sensitivity for angular frequency stimuli as well as for sine-wave gratings in adults under the effect of acute ingestion of alcohol. We measured the contrast sensitivity function (CSF) for gratings of 0.25, 1.25, 2.5, 4, 10, and 20 cycles per degree of visual angle (cpd) as well as for angular frequency stimuli of 1, 2, 4, 24, 48, and 96 cycles/360°. Twenty adults free of ocular diseases, with normal or corrected-to-normal visual acuity, and no history of alcoholism were enrolled in two experimental groups: 1) no alcohol intake (control group) and 2) alcohol ingestion (experimental group). The average concentration of alcohol in the experimental group was set to about 0.08%. We used a paradigm involving a forced-choice method. Maximum sensitivity to contrast for sine-wave gratings in the two groups occurred at 4 cpd sine-wave gratings and at 24 and 48 cycles/360° for angular frequency stimuli. Significant changes in contrast sensitivity were observed after alcohol intake compared with the control condition at spatial frequency of 4 cpd and 1, 24, and 48 cycles/360° for angular frequency stimuli. Alcohol intake seems to affect the processing of sine-wave gratings at maximum sensitivity and at the low and high frequency ends for angular frequency stimuli, both under photopic luminance conditions.

Influence of multiple sclerosis, age and degree of disability, in the position of the contrast sensitivity curve peak.

Context: Contrast sensitivity (CS) function is one of the most important tests available for evaluating visual impairment. Multiple sclerosis (MS) can produce highly selective losses in visual function and psychophysical studies have demonstrated CS deficits for some spatial frequencies. Aims: This work studies the differences in CS between a group of controls and a group of MS patients, focusing on the location of the maximum sensitivity peak, shape of the curve, and determination of the most affected spatial frequencies. Materials and Methods: Using a sinusoidal stimulus the authors assessed CS function in 28 subjects with definitive relapsing remitting MS, and in 50 controls with acuities of 20/25 or better. The peaks of the CS curves were studied by fitting third degree polynomials to individual sets of data. Results: Compared with the control group, the CS function curve for MS subjects showed more deficits in extreme points (low‑ and high‑spatial frequencies). Our results display significant CS losses, at the high‑frequencies band level, in the beginning of the disease. When the disease progresses and the disabilities appear, there are greater losses at the low‑frequencies band level. In average, the CS curve peaks for the MS group were shifted in relation to the control group. Conclusions: CS losses in the MS group suggest an association with ageing and disability level in the expanded disability status scale. The position of the CS function peak is influenced by MS, age, and degree of disability.

Descripción de la función de sensibilidad al contraste en pacientes miopes e hipermétropes / Contrast sensitivity function in myopic and hyperopic patients

Objetivo: describir la Función de Sensibilidad al Contraste (FSC) en pacientes con miopía, astigmatismo miópico, hipermetropía y astigmatismo hipermetrópico. Diseño del estudio: serie de casos, descriptivo. Métodos: se incluyeron sujetos con miopía, astigmatismo miópico, hipermetropía y astigmatismo hipermetrópico, candidatos para cirugía refractiva y evaluados en la Unidad de Cirugía Refractiva de la Clínica de Oftalmología de Cali, con agudeza visual mejor corregida (AVMC) >=20/20, menores de 50 años de edad y sin antecedente de cirugía refractiva. La función sensibilidad al contraste se midió con el sistema OPTEC® 6500 (Stereo Optical Co, Inc., Chicago, USA) en frecuencias espaciales de 1.5, 3.0, 6.0, 12 y 18 ciclos/grado en condiciones fotópicas (85 cd/m2) y mesópicas (3 cd/m2). Se aplicaron las prueba no paramétrica de Wilcoxon y de Mann-Whitney para comparar diferencias entre la FSC entre los grupos de miopía/astigmatismo miópico e hipermetropía/astigmatismo hipermetrópico en las diferentes frecuencias espaciales. Resultados: se incluyeron 188 ojos de 95 sujetos con miopía y astigmatismo miópico (promedio de edad = 30,6 ± 7,6 años, 51% hombres) y 121 ojos de 64 sujetos con hipermetropía y astigmatismo hipermetrópico (promedio de edad = 43 ± 6,1 años, 62 % mujeres). La sensibilidad al contraste en los pacientes de ambos grupos fue mayor significativamente en condiciones fotópicas que en condiciones mesópicas, excepto en la frecuencia espacial de 3 ciclos/grado del grupo de miopía/astigmatismo miópico. Se encontró diferencia estadísticamente significativa del valor de la FSC entre los grupos de miopía/astigmatismo miópico e hipermetropía/astigmatismo hipermetrópico en condiciones fotópicas en casi todas las frecuencias espaciales, excepto en 3 ciclos/grado y en condiciones mesópicas en las frecuencias espaciales de 1.5, 3 y 6 ciclos/grado. Conclusiones: los valores de FSC son mayores en el grupo de pacientes con miopía y astigmatismo miópico que en los del grupo de hipermetropía y astigmatismo hipermetrópico. Estos valores podrían usarse como referencia en estos grupos de pacientes en nuestra población.

Purpose: to describe the contrast sensitivity function (CSF) in patients with myopia, hyperopia and astigmatism. Study design: descriptive case series study. Methods: subjects with myopia/myopic astigmatism and with hyperopia/hyperopic astigmatism looking for refractive surgery, and evaluated at the Unit of Refractive Surgery in the Clínica de Oftalmología de Cali were included. Their Best Spectacle Corrected Visual Acuity (BSCVA) was >=20/20, age less than 50 years and no previous refractive surgery. The CSF was measured using the OPTEC® 6500 (Stereo Optical Co, Inc, Chicago, USA) system for spatial frequencies 1.5, 3.0, 6.0, 12 and 18 cycles/degree in photopic (85 cd/m2) and mesopic (3 cd/m2) conditions. Statistical analysis was done using the Wilcoxon and Mann-Whitney tests for non-parametric samples, comparing the myopia/myopic astigmatism and the hyperopia /hyperopic astigmatism groups. Results: 188 eyes of 95 subjects with myopia/myopic astigmatism (age = 30,6 ± 7.6 years, 51% men) and 121 eyes of 64 subjects with hyperopia/hyperopic astigmatism (age = 43± 6.1 years, 62% women) were analyzed. The CSF was higher in both groups in photopic conditions except in 3 cycles per degree in myopia/myopic astigmatism group. Significant differences in the CSF were found between the two groups in photopic conditions excluding the 3 cycles per degree. In mesopic conditions diff erences were found for the spatial frequencies 1.5, 3 and 6 cycles per degree. Conclusions: The patients of the myopia/myopic astigmatism group had a contrast sensitivity function higher than those of hyperopia/hyperopic astigmatism group. These values could be used as reference for these patients in our population.

Contrast Sensitivity Function of Sound Eye after Occlusion Therapy in the Amblyopic Children

To verify the changes of mesopic and photopic contrast sensitivity function of sound eye whose visual acuity was kept the same after occlusion therapy in the amblyopic children. Fourteen sound eyes of amblyopic children (mean; 7.67 years; S.D., 1.50 years) who kept their visual acuity the same after the occlusion therapy were tested. The children had 6 hours of part-time patch therapy for 3 months prior to this examination. Among 14 amblyopic children, 8 were anisometric and 6 were strabismic amblyopes. Using the visual capacity analyzer which measures the minimal contrast level at from low to high spatial frequencies, the contrast sensitivity of sound eye was measured, under both photopic and mesopic condition, before and after 3 months of occlusion therapy. Comparing the contrast sensitivity of sound eye after the occlusion therapy to that before the occlusion, there was no statistical difference in photopic condition. When it comes to mesopic condition, the contrast sensitivity decreased at the intermediate spatial frequency level (3-13 c.p.d, p=0.028) after the occlusion therapy. The occlusion caused statistically significant decrease in mesopic contrast sensitivity, when the visual acuity was not changed after the occlusion therapy. It may indicate that mesopic contrast sensitivity can be considered as a useful tool for early detection of hidden occlusion amblyopia.

Tópicos em percepção e processamento visual da forma: acuidade visual versus sensibilidade ao contraste / Topics in perception and visual processing of form: visual acuityversus contrast sensitivity

A acuidade visual e a função de sensibilidade ao contraste são medidas clássicas utilizadas para avaliar a capacidade do sistema visual humano. Estas duas funções são os principais indicadores dos aspectos críticos da percepção e do processamento visual da forma ou do detalhe espacial. O objetivo principal deste trabalho é levantar e discutir alguns aspectos teóricos e experimentais básicos relacionados à acuidade visual e à função de sensibilidade ao contraste. A acuidade visual estima a habilidade do sistema visual para discriminar detalhes espaciais, enquanto a função de sensibilidade ao contraste estima a percepção de qualquer padrão em função de sua freqüência espacial.

This work discusses some important aspects about visual acuity, VA, and contrast sensitivity function, CSF. The VA and the CSF are classical functions or measurements used to appreciate the capacity of the human visual system on perception and on visual processing of form or spatial detail. One of the goals of this paper is to discuss important theoretical and experimental aspects related to VA and CSF that are the principal indicators of perception and visual processing of form in humans. Visual acuity estimates the ability of the visual system to resolve spatial details, whereas CSF estimates the perception of any pattern in function of the spatial frequency.

Mesopic Contrast Sensitivity Functions in Amblyopic Children

This study both measured and compared the mesopic contrast sensitivity function and the visual acuity in both normal and amblyopic eyes from amblyopic children using an ACV (visual acuity analyzer). Twenty one amblyopic children (mean age, 8.48 years; S.D., 1.68 years), 11 strabismic amblyopes and 10 anisometropic amblyopes, were tested. Based on a display of the standard optotypes, the minimal contrast level, at which the optotypes were correctly read for all sizes of displays from a distance of 1m, was measured. The contrast ranged from 1% to 99% and the spatial frequencies ranged from 0.6 to- 30cpd using a Landolt ring composed of low (0.6- 2.9 c.p.d.), intermediate (3.0 - 12.9 c.p.d.) and high level (13.0- 30.0 c.p.d.) frequencies. As the visual acuity decreased, the mesopic contrast sensitivity function decreased along the contrast sensitivity axis. However, the peak sensitivity was noted at the same spatial frequencies. A comparison between the normal eye and the corresponding amblyopic eye showed that under mesopic conditions, the contrast sensitivity functions decreased more in the intermediate spatial frequencies than in the other spatial frequencies. The mesopic contrast sensitivity function decreased in the amblyopic eyes, which suggests the possibility of its use an adjunct to an evaluation of amblyopia.

A study of spatiotemporal visual modulation transfer function for diagnosis of early glaucoma / 眼科

At 4Hz and 16Hz temporal frequencies and at a range of 3—37.8 cycles per degree (cpd) of spatial frequency which were divide into 12 grades, an instrument with a flickering sinusoid grate was used to measure the laser retina-visual cortex spatiotemporal visual modulation transfer function (S-TMTF) in patients with glaucoma. There were 34 cases (65 eyes) with early primary open-angle glaucoma (POAG), 18 cases (31 eyes) with moderate or late glaucoma and 19 cases (37 eyes) with suspect glaucoma (SG). In 6 months. 16 patients of SG were followed. The results showed that in patients with early POAG, abnormal S-TMTF values might occur in low frequency region, the abnormal values tended to be general in the middle frequency region, and in the high frequency region all the S-TMTF values were significantly lower than that of the control. In cases with SG, lowering of S-TMTF was seen in many frequency points above 9.5 cpd, but did not found in regions below 9.5 cpd. The S-TMTF values at 16 Hz were lower than that at 4 Hz in each corresponding spatial frequency, and with aggravation of the disease, the greatest discrepancy value appeared to be shifting from high to low frequency points. In the follow-up period, an early glaucomatous visual field change occurred in a female case with ocular hypertension. It is demonstrated that the S-TMTF value is of high sensitivity for diagnosis of POAG, but it is difficult to screen the specific diagnostic frequency point and its critical value.