Is there any correlation between alpha-synuclein levels in tears and retinal layer thickness in Parkinson's disease?

PURPOSE: To determine the total alpha-synuclein (αSyn) reflex tears and its association with retinal layers thickness in Parkinson's disease (PD). METHODS: Fifty-two eyes of 26 PD subjects and 52 eyes of age-and sex-matched healthy controls were included. Total αSyn in reflex tears was quantified using a human total αSyn enzyme-linked immunosorbent assay (ELISA) kit. The retinal thickness was evaluated with spectral-domain optical coherence tomography. The Movement Disorder Society-Unified Parkinsons Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), and Montreal Cognitive Assessment (MoCA) were used to assess motor, non-motor, and cognition. RESULTS: In PD, total αSyn levels were increased compared to control subjects [1.76pg/mL (IQR 1.74-1.80) vs 1.73pg/mL (IQR 1.70-1.77), p < 0.004]. The nerve fiber layer, ganglion cell layer, internal plexiform layer, inner nuclear layer, and outer nuclear layer were thinner in PD in comparison with controls (p < 0.05). The outer plexiform layer and retinal pigment epithelium were thicker in PD (p < 0.05). The total αSyn levels positively correlated with the central volume of the inner nuclear layer (r = 0.357, p = 0.009). CONCLUSION: Total αSyn reflex tear levels were increased in subjects with PD compared to controls. PD patients showed significant thinning of the inner retinal layers and thickening of outer retinal layers in comparison with controls. Total αSyn levels positively correlate with the central volume of the inner nuclear layer in PD. The combination of these biomarkers might have a possible role as a diagnostic tool in PD subjects.

Cambios retinianos periféricos detectados mediante fotografía no midriática de campo ultra amplio en sujetos asintomáticos / Peripheral retinal changes detected by ultra-widefield non-mydriatic photography in asymptomatic subjects

Resumen Objetivo: La fotografía de campo ultra amplio no requiere midriasis, evalúa 200° de la retina y es adecuada para detectar cambios desapercibidos, con riesgo de desprendimiento de retina en individuos asintomáticos; se identificó la frecuencia de cambios periféricos retinianos y cambios con riesgo de desprendimiento de retina, en una muestra de sujetos fáquicos asintomáticos. Materiales y Métodos: Estudio no experimental, analítico, prospectivo, transversal en sujetos con edades de 40-70 años, de cualquier sexo, sin cirugía intraocular previa o síntomas de desgarros retinianos (fotopsias, eritropsia, escotoma periférico). Se obtuvieron imágenes de campo ultra amplio de retina (sin midriasis) con el equipo Optos y se identificó la proporción e intervalos de confianza (I.C.) del 95% de la muestra que tuvo cambios en la retina periférica y cambios con riesgo de desprendimiento de retina (agujeros retinianos, desprendimiento de retina subclínico). Se comparó esta proporción entre sexos y grupos de edad (χ2). Resultados: 1204 ojos de 602 sujetos (promedio de edad 52,92 desviación estándar D.E. ± 7,83 años), 74,41% de los sujetos fueron del sexo femenino. El 16,61% de la muestra presentó cambios periféricos retinianos (I.C. 95% 13,64- 19,58), el 1% de la muestra tuvo cambios con riesgo de desprendimiento de retina. Los cambios periféricos fueron más frecuentes en el grupo de edad de 50-59 años y en mujeres. La miopia superior a -6,00 dioptrías fue infrecuente en ojos con riesgo de desprendimiento de retina. Conclusiones: La fotografía de campo ultra amplio ayuda a demostrar, sin necesidad de dilatar la pupila, que existe una prevalencia baja de cambios retinianos periféricos y cambios con riesgo de desprendimiento de retina en sujetos fáquicos asintomáticos.

Abstract Objective: Ultra wide field photography requires no mydriasis, evaluates 200° of the retina and is adequate to detect overlooked retinal changes, with a risk of retinal detachment in asymptomatic subjects; we identified the frequency of peripheral retinal changes and changes with risk of retinal detachment, in a sample of asymptomatic phakic subjects. Materials and methods: Non-experimental, analytical, prospective, cross- sectional study in subjects aged 40-70 years, of any gender, without previous intraocular surgery or symptoms of retinal tears (photopsia, eritrhopsia, peripheral scotoma). We obtained ultra wide field retinal photographs (without mydriasis) with the Optos device and identified the proportion and 95% confidence intervals (C.I.) of the sample that had peripheral retinal changes and changes with risk of retinal detachment (retinal holes, subclinical retinal detachments). This proportion was compared between genders and age groups (χ2). Results: 1204 eyes of 602 subjects (mean age 59,92 standard deviation ± 7,83 years), 74,41% of the subjects were female. 16,61% of the sample had peripheral retinal changes (95% C.I. 13,64-19,58), 1% of the sample has changes with risk of retinal detachment. Peripheral retinal changes were more frequent in the 50-59 years age group and in women. Myopia over -6.00 diopters was infrequent in eyes with risk of retinal detachment. Conclusions: Ultra wide field photography helped to prove, without the need of mydriasis, that there is a low prevalence of peripheral retinal changes and changes with risk of retinal detachment, in phakic asymptomatic subjects.

Vision-related quality of life after surgery for vitreoretinal disorders in a Mexican population: an observational study.

Visual-related quality of life in retinal diseases has not been explored in the Mexican population, so the study aims to identify it in patients undergoing surgery due to advanced diabetic retinopathy, rhegmatogenous retinal detachment, and other causes of vitrectomy; the Visual Function Quality-25 questionnaire was applied to 76 patients, pre-and postoperative. It was divided into 10 domains and interpreted according to the National Eye Institute scores, where the highest value was the best visual function. Student's t-test for related samples and Wilcoxon's t-test were used to compare each domain between measurements, and Pearson's R test to correlate the total score of age and quality of life; a p value < 0.05 was considered significant. Diabetic retinopathy patients showed an improvement 1 and 3 months after surgery in all domains; in rhegmatogenous retinal detachment, there was an improvement observed up to 3 months, while a decrease in ocular pain was observed in other causes of vitrectomy. Differences found in all the quality-of-life scores were not statistical, but clinically significant. The study shows that visual-related quality of life domains improves after vitrectomy; the inclusion of this analysis might be considered relevant within the parameters of surgical success of the most prevalent vitreoretinal diseases.

Relationship between Helicobacter pylori and undifferentiated non-granulomatous anterior uveitis.

PURPOSE: The relationship of Helicobacter pylori infection with ocular diseases, including anterior uveitis, has been reported. The objective of this study was to determine the presence of anti-H. pylori IgG antibodies in patients with idiopathic non-granulomatous anterior uveitis and compare the results with a control group. METHODS: A prospective, comparative, and cross-sectional study was conducted. Patients with idiopathic granulomatous anterior uveitis and a group of control subjects were included. The presence of anti-H. pylori IgG antibodies was determined. The chi-square test was performed for comparative analysis with GraphPad Prism V5.0 software. RESULTS: Thirty patients with idiopathic non-granulomatous anterior uveitis and 35 control subjects were included. In the determination of anti-H. pylori IgG antibodies, 24 (80%) patients and 19 (54%) control subjects were positive. A significant difference (p = 0.0263) was found between the groups and an odds ratio (OR) of 3.37. CONCLUSIONS: A direct relationship was found between the presence of anti-H. pylori IgG antibodies and idiopathic non-granulomatous anterior uveitis. An association can be established between idiopathic non-granulomatous anterior uveitis and H. pylori infection, without this being a causal or physiopathogenic relationship.

Ketorolac and (-)-Epicatechin change retinal GFAP and NRF2 expression on hyperglycemic CD1 mice.

Our objective was to determine whether (-)-Epicatechin administered alone or simultaneously with topical Ketorolac decreased the relative expression of GFAP and modulated the response of Nrf2 in a mouse model with induced hyperglycemia. We found that GFAP and Nrf2 decreased in the groups that received treatments alone or simultaneous during 8 weeks; even when the effect on the Nrf2 was not pronounced, it showed a higher concentration when GFAP decreased. Our results suggest a protective effect of Ketorolac and (-) - Epicatechin, which seem to limit the preclinical retinal damage caused by inflammation in hyperglycemia.

Compensatory contribution of retinal larger vessels to perfusion density in diabetics without retinopathy.

Vessel and perfusion densities may decrease before diabetic retinopathy appears; it is unknown whether these changes affect the contribution of vessel density to perfusion density. This was a non-experimental, comparative, prospective, cross-sectional study in non-diabetic subjects (group 1) and diabetics without retinopathy (group 2). Vessel and perfusion densities in the superficial capillary plexus were compared between groups at the center, inner, and full regions and by field (superior, temporal, inferior, nasal) using optical coherence tomography angiography. Coefficients of determination (R2) between vessel and perfusion densities were calculated to find the contribution of larger retinal vessels to perfusion density. Percent differences were used to evaluate the contribution of these vessels to perfusion density in a regression model. There were 62 participants, 31 eyes by group; vessel and perfusion densities as well as the coefficients of determination between them were lower in group 2, especially in the nasal field (R2 0.85 vs. 0.71), which showed a higher contribution of larger retinal vessels to perfusion density. The regression model adjusted to a quadratic equation. In diabetics without retinopathy the contribution of vessel density to perfusion density may decrease; a low vessel density may increase the contribution of larger retinal vessels to perfusion density.

Should the outcome of focal photocoagulation for center-sparing diabetic macular edema require expanding the definition of center involvement?

Photocoagulation may still be a therapeutic choice for center-sparing diabetic macular edema. We compared the visual evolution after photocoagulation, in eyes with focal diabetic macular edema, stratified per the location of thickening with optical coherence tomography. We evaluated people with type 2 diabetes and focal diabetic macular edema, before and three weeks after focal photocoagulation. We divided the sample by edema location: central (group1); paracentral (group 2) and pericentral (group 3) and compared the proportions of eyes with baseline visual impairment, visual improvement, and visual deterioration between groups; central edema was evaluated with logistic regression, as an explaining variable of baseline visual impairment and visual improvement. The study included 160 eyes: 77 in group 1, 20 in group 2, 63 in group 3; baseline visual impairment was more frequent in groups 1 and 2 (52.6%) than in group 3 (28.6%, p = 0.002, OR 2.77) and as common in groups 1 (51.9%) and 2 (55.0%, p = 0.8). The proportions of visual improvement and visual deterioration did not differ between groups (p > 0.05). The outcome after focal photocoagulation was similar in paracentral (considered center-sparing) and central macular edema; the definition of center involvement, which needs intravitreal antiangiogenics, should expand to include paracentral thickening.

Comparison of macular retinal sensitivity and its contribution to the foveal sensitivity between diabetic and non-diabetic patients with normal visual acuity.

PURPOSE: To compare the retinal sensitivity and evaluate its contribution to the foveal sensitivity in patients with and without diabetes who maintain normal visual acuity. METHODS: Observational, descriptive, cross-sectional and prospective study in 20 subjects without diabetes (group 1) and 23 with type 2 diabetes mellitus (group 2) that had no ocular abnormalities. Retinal sensitivity was measured with the macular threshold test by the Humphrey's computerized perimeter. The mean sensitivity in each of the 16 points and the foveal sensitivity were compared between groups using the Mann-Whitney's U test; the correlation between retinal sensitivity and foveal sensitivity was analyzed by the Spearman's test and the contribution of each point to the foveal sensitivity was identified by multiple regression. RESULTS: Sixty eyes were evaluated, 30 in group 1 and 30 in group 2; the mean foveal sensitivity was 34.77±0.5dB in group 1 and 32.87±0.6 in group 2. The highest sensitivity of the temporal visual field had an inferior paracentral location (point 3) in both groups. In the linear regression analysis, points which contributed to the foveal sensitivity were 1 in group 1 and points 7 and 15 in group 2. CONCLUSIONS: Subjects without diabetes have a significantly higher sensitivity in the temporal retina compared with those with diabetes; points with highest mean retinal sensitivity do not correspond to the central four. The reduced sensitivity in point 1 decreases the mean foveal sensitivity in subjects with diabetes, because this variable correlates with lower perimetry points.

[Comparación de la densidad capilar parafoveal entre sujetos sanos y diabéticos con y sin retinopatía].

BACKGROUND: Parafoveal capillary density changes have not been characterized in type 2 diabetics without retinopathy. OBJECTIVE: To compare parafoveal capillary density between healthy subjects, and diabetics with and without retinopathy. METHOD: Observational, prospective, transversal and comparative study; subjects without diabetes (group 1), diabetics without retinopathy (group 2), with retinopathy (group 3) and with diabetic macular edema (group 4), without macular ischemia, were included. The study variable was parafoveal capillary density, and the predictor variables were the measures of the foveal avascular zone, retinal thickness and the group. The variables were compared between groups using Kruskal-Wallis and Spearman's Rho tests. RESULTS: One hundred and forty eyes were evaluated; parafoveal capillary density was higher in group 1 than in the rest (p < 0.05). Area, perimeter and diameter of the foveal avascular zone were higher in group 3. A positive correlation existed a positive between parafoveal capillary density and central field thickness in groups 1, 2 and 3. CONCLUSION: Parafoveal capillary density decreases as diabetes-induced damage increase; a reduction may exist in diabetics without retinopathy and normal retinal thickness and foveal avascular zone are normal. The clinical impact of this finding requires further evaluation.

ANTECEDENTES: Los cambios de densidad parafoveal no se han caracterizado en diabéticos tipo 2 sin retinopatía. OBJETIVO: Comparar la densidad capilar parafoveal entre sujetos sanos y diabéticos con y sin retinopatía. MÉTODO: Estudio observacional, prospectivo, transversal y comparativo. Se incluyeron sujetos sin diabetes (grupo 1), diabéticos tipo 2 sin y con retinopatía (grupos 2 y 3), y con edema macular (grupo 4), sin isquemia macular. La variable de estudio fue la densidad capilar parafoveal, y las variables predictoras fueron las mediciones de la ZAF, el grosor retiniano y el grupo. Se compararon las diferencias entre grupos mediante las pruebas de Kruskal-Wallis y Rho de Spearman. RESULTADOS: 144 ojos; la densidad capilar parafoveal del grupo 1 superó la de los restantes (p < 0.05). El área, el perímetro y el diámetro de la ZAF fueron mayores en el grupo 3. Existió correlación positiva entre la densidad capilar parafoveal y el grosor del campo central en los grupos 1, 2, y 3. CONCLUSIONES: La densidad capilar parafoveal disminuye conforme avanza el daño por diabetes tipo 2; puede existir una reducción en sujetos con diabetes sin retinopatía, con grosor retiniano y ZAF normales. El impacto clínico de este hallazgo requiere evaluación adicional.

[Association between visual improvement after photocoagulation and the use of angiotensin converting enzyme inhibitors in diabetic macular oedema]. / Asociación entre la mejoría visual y el uso de inhibidores de la enzima convertidora de angiotensina, en edema macular diabético.

BACKGROUND: Angiotensin converting enzyme inhibitors are effective in delaying the progression of diabetic retinopathy. It is unknown if their use is associated with a better visual outcome in patients with diabetic macular oedema. MATERIAL AND METHODS: A non-experimental, comparative, longitudinal and retrospective study was performed on patients with diabetic macular oedema treated by focal photocoagulation, and with systemic arterial hypertension treated with angiotensin converting enzyme inhibitors (Group 1), and without hypertension (Group 2). The dependent variable was the proportion with visual improvement, operatively defined as the gain of one or more lines of vision three weeks after photocoagulation. The independent variable was the use of angiotensin converting enzyme inhibitors. The proportion of eyes with visual improvement after treatment was compared between groups using the Chi squared (χ(2)) test. RESULTS: A total of 33 eyes (51.6%) were assigned to group 1, and 31 (48.2%), to group 2. The mean of visual acuity improved after three weeks, compared with baseline (p=0.002). The proportion of eyes with visual improvement did not differ between patients treated with angiotensin converting enzyme inhibitors (45.5%) and those that did not use them (51.6%, p=0.4). CONCLUSIONS: There was no statistical difference in the proportion of eyes with visual improvement between patients treated with angiotensin converting enzyme inhibitors and in those where they were not used. There is no support for the inhibition of angiotensin II in addition to photocoagulation for improving the outcome in patients with diabetic macular oedema.