After-effect on tear film quality and quantity of reading on laptop computer screen versus hardcopy.

CLINICAL RELEVANCE: Electronic displays, including laptops, tablets, and smartphones, have dramatically altered the way information is accessed and become significant factors in human daily life. They interfere with the blink rate and increase dry eye symptoms, which lead to more discomfort compared to hard copy while reading. BACKGROUND: Digital eye strain occurs when an individual suffers from symptoms, or they are exacerbated, while performing a task requiring digital screen viewing. This study assessed the tear film status immediately following reading on a laptop computer screen versus an identical hard copy. METHODS: Thirty young adults with normal ocular health and reporting no significant symptoms of dry eye (ocular surface disease index (OSDI) score < 13 and non-invasive tear break-up time (NITBUT) > 10 seconds) read a text as hard copy and on a laptop computer screen for 30 min on separate days in a random sequence in a controlled reading experimental condition. The texts were matched in size and contrast and presented at a viewing distance of 40 cm. The NITBUT and strip meniscometry tube tests were administered at baseline and after reading in both conditions. RESULTS: The median baseline NITBUT decreased from 13.0 s to 10.0 s (P < 0.001) after hardcopy reading and to 7.0 (P < 0.001) after reading from a laptop computer screen, with a significant difference between the task medium (P = 0.001). The baseline strip meniscometry tube results decreased from 6.7 mm to 5.0 mm (P < 0.001) after hardcopy reading and to 5.0 mm (P < 0.001) after reading from a laptop computer screen, but there was no significant difference with the task medium (P = 0.085). CONCLUSION: Reading in both conditions led to tear film instability in terms of the tear film quality and quantity. Additionally, the computer screen has a greater impact on the TBUT compared to hardcopy reading, while these two reading mediums had a similar effect on the tear volume.

Comparison of Visual Field Measurements in Glaucomatous Eyes using Oculus and Metrovision Perimeters.

Purpose: To investigate the agreement between the Oculus and Metrovision perimeters in the visual field evaluation of glaucoma patients. Methods: In this cross-sectional study, 41 consecutive glaucoma patients were enrolled. After detailed clinical examinations, visual field testing was performed for all patients using the Oculus and Metrovision perimeters. The interval time between the two visual field examinations was 30 min. Results: A total of 22 participants were male (53.7%) and the mean ± standard deviation (SD) age was 58.6 ± 9.1 years. The absolute average of the mean deviation (MD) in the oculus perimeter (8.24 ± 4.92 dB) was higher compared to the Metrovision perimeter (4.02 ± 4.62; P < 0.001). This difference was also evident in the Bland-Altman graph. The loss variance (pattern SD) values of Oculus perimeter (28.58 ± 16.40) and Metrovision perimeter (28.10 ± 28.45) were not significantly different; although based on the Bland-Altman plots in the lower MDs, the agreement is better and the data dispersion is lower, and in the higher MDs, the agreement is lower. The parameters of four visual field quadrants were also compared and showed poor correlations (P < 0.001). Conclusion: The Oculus and Metrovision perimeter devices have good agreement in lower MDs; however, they cannot be used interchangeably.

Seasonal variations in anterior segment angle parameters in myopes and emmetropes.

CLINICAL RELEVANCE: Seasonal variations are known to occur in a range of ocular parameters and in conditions including refractive error and glaucoma. It is of clinical importance to know if seasonal changes also occur in anterior segment angle parameters, given that they can influence these conditions. BACKGROUND: The study aimed to examine the seasonal variations in anterior segment angle parameters in healthy young adults. METHODS: Twenty-three emmetropic participants with a mean age of 26.17 ± 4.43 years and 22 myopic participants with a mean age of 27.27 ± 4.47 years completed four seasons of data collection. Anterior segment angle parameters were measured using swept-source anterior segment optical coherence tomography. Intraocular pressure (IOP) and objective refraction were also measured. Repeated-measures analysis of variance was used to determine the effect of season and refractive error on the various ocular parameters. RESULTS: A significant main effect of season was found for the majority of anterior segment angle parameters, including the angle opening distance at 500 and 750 µm from the scleral spur (p = 0.02, p = 0.006, respectively), angle recess area at 500 and 750 µm from the scleral spur (both p = 0.002), and trabecular iris space area at 500 and 750 µm from the scleral (p = 0.02, p = 0.008, respectively). However, measures of anterior chamber depth and trabecular iris angle did not exhibit statistically significant seasonal variations (all p > 0.05). A significant main effect of season was also found for the changes in IOP (p = 0.004) and objective refraction (p < 0.001). There was no season by refractive group interaction for any anterior segment angle parameter or IOP (all p > 0.05). CONCLUSION: There is a small but significant seasonal changes in the anterior segment angle parameters, refractive error, and IOP in healthy young adult males, in which the anterior segment angle dimensions are narrower, the IOP is higher, and the refraction is more myopic during winter.

Comparison of corneal biomechanical properties in healthy thin corneas with matched keratoconus eyes.

PURPOSE: To compare corneal biomechanical parameters of normal thin corneas with matched keratoconus eyes. SETTING: Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. DESIGN: Cross-sectional comparative study. METHODS: Dynamic corneal response parameters of Corvis ST were compared in 61 eyes with keratoconus with 61 matched healthy thin corneas (corneal thinnest point <500 µm), while corneal thickness, biomechanically corrected intraocular pressure, and age were considered covariates. The receiving operator sensitivity curve analysis was used to determine the cutoff point with the highest sensitivity and specificity, and the area under the curve (AUC) for each parameter. RESULTS: All biomechanical parameters were statistically significant between the 2 groups except for the first ( P = .947) and second ( P = .582) applanation length, first ( P = .783) and second ( P = .301) applanation velocity, and deformation amplitude in the highest concavity phase ( P = .106). The highest mean difference between groups (12.89 ± 2.03 mm Hg/mm) was related to the stiffness parameter at the first applanation (SPA1). Although the Corvis biomechanical index and tomographic biomechanical index had the highest detection ability based on their AUC (0.912 and 0.959, respectively), among the standard and combined biomechanical parameters except for keratoconus screening parameters, the highest discriminative ability was related to SPA1 with AUC, sensitivity, and specificity of 0.793, 60.66%, and 90.16%, respectively. CONCLUSIONS: Keratoconus corneas were significantly softer compared with healthy thin corneas of matched thickness. Optimal cutoff points close to the maximum value defined for screening parameters limit their clinical use for differentiation purposes in these particular types of cases.

Efficacy of five-flash intense pulsed light therapy technique in patients with meibomian gland dysfunction.

CLINICAL RELEVANCE: Meibomian gland dysfunction is the main cause of evaporative dry eye disease and can lead to ocular discomfort and ocular surface damage. Early diagnosis and management of this condition can prevent its impact on patients 'visual health and quality of life. BACKGROUND: In the last decade, intense pulsed light therapy (IPL) has been introduced as a therapeutic option for patients with meibomian gland dysfunction (MGD). Various treatment modalities and protocols have been reported to increase the efficacy of this technique. This study aimed to assess the efficacy of a novel five-flash IPL technique in combination with home-based therapy and to compare it with conventional home care alone in patients with MGD. METHODS: In a randomised controlled trial, 100 symptomatic MGD patients were enrolled. The treatment group underwent three sessions of a five-flash IPL therapy. For all participants, eyelid warming, lid hygiene and lubricant therapy was prescribed. Ocular surface parameters were compared for control and treatment groups. RESULTS: Ocular Surface Disease Index (OSDI), non-invasive keratograph tear break up time (NIKBUT), fluorescein TBUT, MG expressibility, meibum quality and tear osmolarity were improved at follow up visits in both groups (p < 0.05). On day 75, NIKBUT was significantly higher in the IPL group (p = 0.045). The IPL treatment effect was not statistically significant (p > 0.05), except for bulbar and limbal hyperaemia (p = 0.02 and p = 0.02). In both groups, younger patients showed more improvement in NIKBUT (p = 0.02, r = -0.32; p < 0.001, r = -0.52). CONCLUSION: IPL therapy combined with conventional home-based therapy, and home care alone are both effective for patients with MGD. IPL may have an additional role in the improvement of ocular hyperaemia.

The Effect of Meibomian Gland Dysfunction Treatment on Sleep Quality.

PURPOSE: To assess the therapeutic efficacy of a combinational therapy, including conventional treatment and intense pulsed light (IPL) technique on sleep quality of patients with meibomian gland dysfunction (MGD). METHODS: Fifty participants with a clinical diagnosis of MGD were enrolled in this study. Participants underwent three sessions of IPL therapy. There was a 2-week interval between IPL sessions 1 and 2 and 1 month between sessions 2 and 3. Treatment was supplemented with conventional home-based therapy (including lid hygiene, warm compress, eyelid massage, and lid margin scrub) for MGD. Dry eye symptomatology, tear film, and ocular surface parameters were evaluated at baseline (day 0) and days 15, 45, and 75. Sleep quality was assessed before and after the study using Pittsburgh Sleep Quality Index (PSQI). RESULTS: PSQI components improved significantly at day 75 in comparison with the baseline (all P < 0.05). Ocular Surface Disease Index (OSDI) score, noninvasive Keratograph tear break-up time (NIKBUT), fluorescein tear break-up time (FTBUT), meibomian gland expressibility, meibum quality score, and tear osmolarity improved at follow-up visits (P < 0.05). Younger patients showed more improvement in NIKBUT, sleep quality, and duration (P = 0.024, P = 0.047, and P = 0.008). Sleep latency decreased with increased NIKBUT and FTBUT and decreased OSDI score (P = 0.001, P = 0.005, and P = 0.041). CONCLUSIONS: The treatment of MGD is effective for improving sleep quality. Younger patients may preferentially benefit from the treatment.

Wide-field choroidal thickness and vascularity index in myopes and emmetropes.

PURPOSE: To study regional variations in choroidal thickness (CT), luminal thickness and stromal thickness of the choroid, and choroidal vascularity index (CVI) in low myopic and emmetropic eyes using wide-field optical coherence tomography (OCT). METHODS: Sixty-nine healthy young adults between 20 and 38 years of age participated in this study, including 40 low myopes (mean ± SD spherical equivalent (MSE) refractive error: -3.00 ± 1.39 D, range: -6.00 to -0.62 D) and 29 emmetropes (MSE: -0.05 ± 0.09 D, range: -0.25 to +0.12 D). Wide-field CT, luminal thickness, stromal thickness and CVI were measured across five eccentricities (fovea, parafovea, perifovea; near-periphery and periphery) and four quadrants (nasal, temporal, inferior and superior), in vertical and horizontal meridians, while controlling for a range of extraneous factors potentially influencing the CT. Custom-written software was used to segment and binarize the OCT images. RESULTS: Wide-field CT, luminal thickness and stromal thickness, averaged across all participants, exhibited significant topographical variation, with the foveal (379 ± 8 µm, 200 ± 4 µm, 179 ± 4 µm, respectively) and peripheral (275 ± 8 µm, 161 ± 4 µm, 114 ± 4 µm, respectively) regions presenting the thickest and thinnest regions (all p < 0.001). Wide-field CVI showed a progressively higher percentage (greater vascularity) with increasing eccentricity from the fovea towards the periphery (p < 0.001). Macular CT and stromal choroidal thickness were significantly thinner in myopes compared to emmetropes (p < 0.05). Myopes (55.7 ± 0.3%) showed a slightly higher CVI compared with emmetropes (54.4 ± 0.4%) (p < 0.05). CONCLUSIONS: Low myopia in young adults was associated with significant choroidal thinning across the macular, but not extramacular regions, with this decrease in choroidal thickness mostly attributed to thinning in the stromal component of the choroid, rather than the luminal (vascular) component.

Under-correction or full correction of myopia? A meta-analysis

PURPOSE: To compare the effect of full-correction versus under-correction on myopia progression. METHODS: A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality assessment of the literature was evaluated according to the Critical Appraisal Skills Program. Statistical analysis was performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (two randomized controlled trials [RCTs] and four non-RCTs) with 695 subjects (full-correction group, n = 371; under-correction group, n = 324) aged 6 to 33 years. Using cycloplegic refraction, the pooled difference in mean of myopia progression was - 0.179 D [lower and higher limits: -0.383, 0.025], which was higher but not in full correction group as compared to under correction group (p = 0.085). Regarding studies using non-cycloplegic subjective refraction according to maximum plus for maximum visual acuity, the pooled difference in myopia progression was 0.128 D [lower and higher limits: -0.057, 0.312] higher in under-correction group compared with full-correction group (p = 0.175). Although, difference in myopia progression did not reach significant level in either cycloplegic or non-cycloplegic refraction. CONCLUSIONS: Our findings suggest that, myopic eyes which are fully corrected with non-cycloplegic refraction with maximum plus sphere, are less prone to myopia progression, in comparison to those which were under corrected. However, regarding cycloplegic refraction, further studies are needed to better understand these trends

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Under-correction or full correction of myopia? A meta-analysis.

PURPOSE: To compare the effect of full-correction versus under-correction on myopia progression. METHODS: A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality assessment of the literature was evaluated according to the Critical Appraisal Skills Program. Statistical analysis was performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (two randomized controlled trials [RCTs] and four non-RCTs) with 695 subjects (full-correction group, n=371; under-correction group, n=324) aged 6 to 33 years. Using cycloplegic refraction, the pooled difference in mean of myopia progression was - 0.179 D [lower and higher limits: -0.383, 0.025], which was higher but not in full correction group as compared to under correction group (p=0.085). Regarding studies using non-cycloplegic subjective refraction according to maximum plus for maximum visual acuity, the pooled difference in myopia progression was 0.128 D [lower and higher limits: -0.057, 0.312] higher in under-correction group compared with full-correction group (p=0.175). Although, difference in myopia progression did not reach significant level in either cycloplegic or non-cycloplegic refraction. CONCLUSIONS: Our findings suggest that, myopic eyes which are fully corrected with non-cycloplegic refraction with maximum plus sphere, are less prone to myopia progression, in comparison to those which were under corrected. However, regarding cycloplegic refraction, further studies are needed to better understand these trends.

Effect of cyclopentolate versus tropicamide on anterior segment angle parameters in three refractive groups.

CLINICAL RELEVANCE: Frequent clinical application of cycloplegia in clinical practice makes it essential to assess how this condition influences anterior segment angle parameters. BACKGROUND: This study aims to compare the effects of cyclopentolate and tropicamide on anterior segment angle parameters in three adult refractive groups. METHODS: Sixty healthy individuals were recruited and assigned into three refractive groups according to inclusion criteria. At baseline visit, anterior segment angle parameters were measured using anterior segment optical coherence tomography in the right eye. All measurements were repeated at two separate visits, one week apart, after administration of tropicamide 1% and cyclopentolate 1% at similar conditions. Main outcome measures were angle-opening distance, trabecular iris angle, trabecular iris space area and anterior chamber depth. Anterior segment angle parameters were recorded at temporal areas (180 degrees). RESULTS: Sixty participants (29 men and 31 women, age: 27.82 ± 4.71-years) completed the experiment. Baseline mean spherical equivalents were +1.52 ± 1.20 D, -0.04 ± 0.33 D and -1.91 ± 0.91-D in hyperopic, emmetropic and myopic groups, respectively. No statistically significant differences were found between tropicamide and cyclopentolate for all angle parameters in three refractive groups. Both drops induced an increase in all parameters in three refractive groups. Analysis between refractive groups revealed that a more hyperopic refraction was associated with less trabecular iris angle, angle-opening distance and anterior chamber depth parameters in baseline, after tropicamide and cyclopentolate instillations. CONCLUSIONS: Topical application of cycloplegic eye drops in healthy individuals leads to small but significant changes in anterior chamber depth and anterior segment angle parameters, regardless of refractive status. Moreover, lower values of anterior chamber depth and anterior segment angle parameters in hyperopic individuals after administration of cycloplegic drops should be taken into account during biometric measurement and phakic intraocular lens implantation. Due to shorter effect and recovery time and less ocular/systemic reaction of tropicamide versus cyclopentolate, tropicamide could be a recommended cycloplegic agent for diagnostic and therapeutic procedures.

The Effect of Contact Lens-spectacle Reversed Galilean Telescope on the Visual Field of Patients with Open-angle Glaucoma.

PURPOSE: Glaucoma causes irreversible visual field defects. This study aims to evaluate the effect of a reversed Galilean telescope on the visual field of patients with open-angle glaucoma. METHODS: Fifty-two glaucoma patients with a restricted visual field were recruited for this study. Central 30° visual field measurements were performed using a Humphrey visual field analyzer before and after applying the reversed Galilean telescope. To be more cosmetically acceptable, a combination of contact lens-spectacle was used as the reversed Galilean telescope. RESULTS: Our data analysis showed that the reversed Galilean telescope had a significant effect on all measured perimetric indices. Visual field index (VFI) improved from a basic value of 44.38 ± 26.96 to 49.30 ± 29.83 percent by using the reversed telescope (P < 0.001). Moreover, the mean deviation (MD) was significantly improved from the initial value of -19.91 ± 7.19 dB to a value of -18.69 ± 7.73 dB (P < 0.001). However, our results showed a significant reduction in the pattern standard deviation (PSD) comparing before (9.83 ± 2.82) and after (8.51 ± 3.30) values using the reversed Galilean telescope (P < 0.001). CONCLUSION: The contact lens-spectacle combination reversed Galilean telescope significantly improved the central 30° visual field of glaucoma patients with the restricted visual field.

Analysis of Age, Gender, and Refractive Error-Related Changes of the Anterior Corneal Surface Parameters Using Oculus Keratograph Topography.

PURPOSE: To assess refractive error, gender, and age-related differences in corneal topography of a normal population with Oculus Keratograph 4. METHODS: This cross-sectional study included a total of 500 normal eyes of 500 individuals with ages ranging from 10 to 70 years. All participants underwent detailed ocular examinations, including visual acuity measurement, slit-lamp examination, and refractive error evaluation. Slit-lamp examination was performed for all individuals to rule out apparent corneal diseases. Corneal topography parameters were assessed using Oculus Keratograph. The data were analyzed based on gender, refractive error, and age groups using independent sample t-test and one-way analysis of variance. RESULTS: Of a total of 500 participants (age: 29.51 ± 11.53 years) recruited for the present study, 66.4% were female, and 33.6% were male. The mean spherical equivalent of refraction was - 0.98 ± 1.65 diopters. Significant differences were noted in steep keratometry (P = 0.035) and corneal astigmatism (P = 0.014) between genders. Assessment of the data based on refractive error revealed significant differences in an index of vertical asymmetry (P < 0.001), index of height asymmetry (P = 0.003), and index of height decentration (P = 0.011). Considering age groups, significant differences were observed in flat keratometry readings (P < 0.001), mean corneal astigmatism (P = 0.02), minimum radius of curvature (P = 0.037), and apex power (P < 0.001). CONCLUSIONS: There was a prominent variation in some topographic parameters based on gender, age, and refractive error. The information on corneal parameters obtained with Oculus Keratograph from normal eyes provides a reference for comparison with diseased corneas.

Normative values of visual evoked potentials in Northeastern of Iran / Valores normativos de los potenciales evocados visuales en el Nordeste de Irán

Purpose: Visual evoked potentials (VEPs) provide important diagnostic information related to the functional integrity of the visual pathways. The aim of this study was to establish normative values of different components of pattern reversal VEPs on Iranian normal adult subjects. Methods: Monocular and binocular pattern reversal VEPs were recorded on 59 healthy participants (22.55 ± 3.79 years old) using the Roland RETI system for two check sizes of 15 and 60 min of arc. The measured VEP components were the latencies of N75, P100, N135 and amplitude of N75-P100. Results: Repeated measures ANOVA showed that viewing eye condition has a significant impact on the amplitude of N75-P100 (P < 0.001, F = 13.89). Also, the effect of check size on the latencies of N75, P100, N135, amplitude of N75-P100 (P ≤ 0.010), as well as the intraocular difference of P100 latency and amplitude N75-P100 (P = 0.007) was significant. More specifically, the amplitude of N75-P100 in both check sizes significantly differed between gender groups (P < 0.023). Conclusion: According to the results of this study, VEPs components are affected by the stimulus size, monocular and binocular recording conditions and gender. Therefore, it is necessary to determine the normative values of VEPs in each population, so that the results could be used in clinical studies

Objetivo: Los potenciales evocados visuales (PEV) aportan información diagnóstica importante relacionada con la integridad funcional de las vías visuales. El objetivo de este estudio fue establecer los valores normativos de los diferentes componentes de la reversión del patrón de PEV en adultos normales iraníes. Métodos: Se registraron los valores de reversión monocular y binocular del patrón de PEV en 59 participantes sanos (22,55 ± 3,79 años), utilizando el sistema Roland RETI para dos tamaños de comprobación de 15 y 60 min de arco. Los componentes medidos de PEV fueron las latencias de N75, P100, N135 y la amplitud de N75-P100. Resultados: La repetición de las medidas ANOVA reflejó que la situación del ojo de visión tiene un impacto significativo sobre la amplitud de N75-P100 (P < 0,001, F = 13,89). De igual modo, el efecto del tamaño de la comprobación de las latencias de N75, P100, N 135, la amplitud de N75-P100 (P ≤ 0,010), así como la diferencia intraocular de la latencia de P100 y la amplitud de N75-P100 (P = 0,007) fue significativo. Más específicamente, la amplitud de N75-P100 en ambos tamaños de comprobación difirió considerablemente entre los grupos de sexos (P < 0,023). Conclusión: Con arreglo a los resultados de este estudio, los componentes de los PEV se ven afectados por el tamaño del estímulo, las situaciones del registro monocular y binocular, y el sexo. Por tanto, es necesario determinar los valores normativos de los PEV en cada población, para poder utilizar los resultados en estudios clínicos

Normative values of visual evoked potentials in Northeastern of Iran.

PURPOSE: Visual evoked potentials (VEPs) provide important diagnostic information related to the functional integrity of the visual pathways. The aim of this study was to establish normative values of different components of pattern reversal VEPs on Iranian normal adult subjects. METHODS: Monocular and binocular pattern reversal VEPs were recorded on 59 healthy participants (22.55±3.79 years old) using the Roland RETI system for two check sizes of 15 and 60min of arc. The measured VEP components were the latencies of N75, P100, N135 and amplitude of N75-P100. RESULTS: Repeated measures ANOVA showed that viewing eye condition has a significant impact on the amplitude of N75-P100 (P<0.001, F=13.89). Also, the effect of check size on the latencies of N75, P100, N135, amplitude of N75-P100 (P≤0.010), as well as the intraocular difference of P100 latency and amplitude N75-P100 (P=0.007) was significant. More specifically, the amplitude of N75-P100 in both check sizes significantly differed between gender groups (P<0.023). CONCLUSION: According to the results of this study, VEPs components are affected by the stimulus size, monocular and binocular recording conditions and gender. Therefore, it is necessary to determine the normative values of VEPs in each population, so that the results could be used in clinical studies.

Structure versus function in high myopia using optical coherence tomography and automated perimetry.

BACKGROUND: To examine the structure-function relationship between retinal thickness using spectral-domain optical coherence tomography and standard automated perimetry in high myopia. METHODS: The study population comprised 58 highly myopic individuals with no posterior abnormalities (mean spherical equivalent refraction ≤ -6.00 D and axial length ≥ 26.0 mm). All eyes underwent optical coherence tomography with the Spectralis spectral domain optical coherence tomograph and visual field evaluation with the Humphrey Field Analyzer II-i. Average macular layer thicknesses in each quadrant were calculated in a 6 × 6 mm area centred on the fovea. The visual field was assessed from 17 central locations (10°), approximately the equivalent of the area tested by optical coherence tomography in the macular scan. Linear correlations were made between different macular layer thicknesses and peripapillary retinal nerve layer thickness with their matched visual field sensitivities. RESULTS: Participant ages were 28.2 ± 6.4 years, mean spherical equivalent refractions were -8.20 ± 1.40 D and axial lengths were 26.7 ± 0.7 mm. There were significant positive correlations between layer thickness and corresponding visual field sensitivities as follows: ganglion cell layer in all quadrants, temporal quadrant of the nerve fibre layer with nasal quadrant of the visual field, inferior quadrant of the outer nuclear layer with superior visual field, and temporal-superior peripapillary nerve fibre layer with nasal-inferior visual field. CONCLUSION: The correlation between retinal layer thicknesses and visual field sensitivity could be explained by myopia-related losses due to lateral retinal stretching, with further research required to investigate this.

The effect of trabeculectomy on contrast sensitivity, corneal topography and aberrations.

PURPOSE: To investigate the effect of trabeculectomy on corneal topography, corneal sensitivity and aberrations. METHODS: Twenty-four eyes of 24 subjects with open-angle glaucoma who required glaucoma filtration surgery were assessed. The evaluation of corneal topography, corneal sensitivity and aberrations were done before the trabeculectomy procedure, 1 week and 1 month after the trabeculectomy. RESULTS: There were significant differences in cylindrical power (P = 0.02), contrast sensitivity at 12 cycle/degree spatial frequency (P = 0.04) as well as high order aberration (P = 0.04) and high order without spherical component (P = 0.02) following trabeculectomy. However, significant differences were found for keratometric results and Fourier index in 3 and 6 mm pupil diameters between pre- and post-trabeculectomy (P > 0.05). CONCLUSIONS: According to the findings of the current study, trabeculectomy affects contrast sensitivity at 12 cycle/degree spatial frequency, higher-order aberration and higher order without spherical component aberration 1 month after trabeculectomy. Being knowledgeable about these changes may lead to some advancement in post-surgical management of patients particularly in early stages following trabeculectomy.

Comparison of cyclopentolate versus tropicamide cycloplegia: A systematic review and meta-analysis / Comparación de la cicloplejia con Ciclopentolato y Tropicamida: revisión sistemática y meta-análisis

Purpose: The aim of the present meta-analysis is to compare the efficacy of cyclopentolate and tropicamide in controlling accommodation during refraction. Methods: A comprehensive literature search was performed in PubMed, Scopus, Science direct and Ovid databases by the key words: "tropicamide"; "cyclopentolate"; "cycloplegia" and "cycloplegic" from inception to April 2016. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2; Biostat Inc., USA). Results: The present meta-analysis included six studies (three randomized controlled trials and three case-control studies). Pooled standardized difference in the mean changes in the refractive error was 0.175 D [lower and upper limits: -0.089; 0.438] more plus in the cyclopentolate group compared to the tropicamide group; however, this difference was not statistically significant (p = 0.194; Cochrane Q value = 171.72 (p < 0.05); I2 = 95.34%). Egger's regression intercept was -5.33 (p = 0.170). Considering type of refractive errors; refractive assessment procedure and age group; although cycloplegic effect of cyclopentolate was stronger than tropicamide; however, this effect was only statistically significant in children; hyperopic patients and with retinoscopy. Conclusion: We suggest that tropicamide may be considered as a viable substitute for cyclopentolate due to its rapid onset of action. Although these results should be used cautiously in infants and in patients with high hyperopia or strabismus when using tropicamide as the sole cycloplegic agent especially in situations that the findings are variable or there is no consistency between the examination results and clinical manifestations of the visual problems

Objetivo: El objetivo del presente meta-análisis es comparar la eficacia de ciclopentolato y tropicamida a la hora de controlar la acomodación durante la refracción. Métodos: Se realizó una búsqueda amplia en la literatura en las bases de datos de PubMed, Scopus, Science direct y Ovid, utilizando las palabras clave: "tropicamida", "ciclopentolato", "cicloplejia" y "ciclopléjico" desde sus inicios a Abril de 2016. La calidad metodológica de la literatura se evaluó con arreglo a Oxford Center for Evidence Based Medicine y la escala Newcastle-Ottawa modificada. Los análisis estadísticos se realizaron utilizando el software Comprehensive Meta-Analysis (versión 2, Biostat Inc., EEUU). Resultados: El presente meta-análisis incluyó seis estudios (tres ensayos controlados aleatorizados y tres estudios de casos-control). La diferencia estandarizada combinada de los cambios medios del error refractivo fue de 0,175 D [límites inferior y superior: -0,089, 0,438], más acusada en el grupo ciclopentolato con respecto al grupo tropicamida aunque, sin embargo, esta diferencia no fue estadísticamente significativa (p = 0,194, Valor Q de Cochrane = 171,72 (p < 0,05), I2 = 95,34%). El valor del intercepto de regresión de Egger fue de -5,33 (p = 0,17). Considerando el tipo de errores refractivos, el procedimiento de valoración refractiva y el grupo de edad, aunque el efecto ciclopléjico de ciclopentolato fue más fuerte que el de tropicamida, dicho efecto fue únicamente significativo en niños, pacientes hipermétropes, y con retinoscopia. Conclusión: Sugerimos la consideración de tropicamida como sustituto viable de ciclopentolato, debido a su rápido inicio de acción. Aunque estos resultados deberían utilizarse con precaución en niños y en pacientes con elevada hipermetropía o estrabismo al utilizar tropicamida como único agente ciclopléjico, especialmente en situaciones en las que los hallazgos sean variables, o no exista consistencia entre los resultados del examen y las manifestaciones clínicas de los problemas visuales

Comparison of cyclopentolate versus tropicamide cycloplegia: A systematic review and meta-analysis.

PURPOSE: The aim of the present meta-analysis is to compare the efficacy of cyclopentolate and tropicamide in controlling accommodation during refraction. METHODS: A comprehensive literature search was performed in PubMed, Scopus, Science direct and Ovid databases by the key words: "tropicamide"; "cyclopentolate"; "cycloplegia" and "cycloplegic" from inception to April 2016. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2; Biostat Inc., USA). RESULTS: The present meta-analysis included six studies (three randomized controlled trials and three case-control studies). Pooled standardized difference in the mean changes in the refractive error was 0.175 D [lower and upper limits: -0.089; 0.438] more plus in the cyclopentolate group compared to the tropicamide group; however, this difference was not statistically significant (p=0.194; Cochrane Q value=171.72 (p<0.05); I2=95.34%). Egger's regression intercept was -5.33 (p=0.170). Considering type of refractive errors; refractive assessment procedure and age group; although cycloplegic effect of cyclopentolate was stronger than tropicamide; however, this effect was only statistically significant in children; hyperopic patients and with retinoscopy. CONCLUSION: We suggest that tropicamide may be considered as a viable substitute for cyclopentolate due to its rapid onset of action. Although these results should be used cautiously in infants and in patients with high hyperopia or strabismus when using tropicamide as the sole cycloplegic agent especially in situations that the findings are variable or there is no consistency between the examination results and clinical manifestations of the visual problems.

Distribution of Different Sized Ocular Surface Vessels in Diabetics and Normal Individuals.

PURPOSE: To compare the distribution of different sized vessels using digital photographs of the ocular surface of diabetic and normal individuals. METHODS: In this cross-sectional study, red-free conjunctival photographs of diabetic and normal individuals, aged 30-60 years, were taken under defined conditions and analyzed using a Radon transform-based algorithm for vascular segmentation. The image areas occupied by vessels (AOV) of different diameters were calculated. The main outcome measure was the distribution curve of mean AOV of different sized vessels. Secondary outcome measures included total AOV and standard deviation (SD) of AOV of different sized vessels. RESULTS: Two hundred and sixty-eight diabetic patients and 297 normal (control) individuals were included, differing in age (45.50 ± 5.19 vs. 40.38 ± 6.19 years, P < 0.001), systolic (126.37 ± 20.25 vs. 119.21 ± 15.81 mmHg, P < 0.001) and diastolic (78.14 ± 14.21 vs. 67.54 ± 11.46 mmHg, P < 0.001) blood pressures. The distribution curves of mean AOV differed between patients and controls (smaller AOV for larger vessels in patients; P < 0.001) as well as between patients without retinopathy and those with non-proliferative diabetic retinopathy (NPDR); with larger AOV for smaller vessels in NPDR (P < 0.001). Controlling for the effect of confounders, patients had a smaller total AOV, larger total SD of AOV, and a more skewed distribution curve of vessels compared to controls. CONCLUSION: Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

Part-time versus full-time occlusion therapy for treatment of amblyopia: A meta-analysis.

PURPOSE: To compare full-time occlusion (FTO) and part-time occlusion (PTO) therapy in the treatment of amblyopia, with the secondary aim of evaluating the minimum number of hours of part-time patching required for maximal effect from occlusion. METHODS: A literature search was performed in PubMed, Scopus, Science Direct, Ovid, Web of Science and Cochrane library. Methodological quality of the literature was evaluated according to the Oxford Center for Evidence Based Medicine and modified Newcastle-Ottawa scale. Statistical analyses were performed using Comprehensive Meta-Analysis (version 2, Biostat Inc., USA). RESULTS: The present meta-analysis included six studies [three randomized controlled trials (RCTs) and three non-RCTs]. Pooled standardized difference in the mean changes in the visual acuity was 0.337 [lower and upper limits: -0.009, 0.683] higher in the FTO as compared to the PTO group; however, this difference was not statistically significant (P = 0.056, Cochrane Q value = 20.4 (P = 0.001), I2 = 75.49%). Egger's regression intercept was 5.46 (P = 0.04). The pooled standardized difference in means of visual acuity changes was 1.097 [lower and upper limits: 0.68, 1.513] higher in the FTO arm (P < 0.001), and 0.7 [lower and upper limits: 0.315, 1.085] higher in the PTO arm (P < 0.001) compared to PTO less than two hours. CONCLUSIONS: This meta-analysis shows no statistically significant difference between PTO and FTO in treatment of amblyopia. However, our results suggest that the minimum effective PTO duration, to observe maximal improvement in visual acuity is six hours per day.