Assessment of ganglion cell complex thickness and its correlation with retinal sensitivity using microperimetry 6 months after epiretinal membrane surgery.

PURPOSE: To verify the correlation between the full-macular and the ganglion cell complex (GCC) thickness measurements and retinal sensitivity (RS) assessed by microperimetry (MP) 6 months after surgical peeling for idiopathic epiretinal membrane (ERM). METHODS: Forty-three were submitted to pars-plana posterior vitrectomy (PPV) with concomitant peeling of internal limiting membrane (ILM) for idiopathic ERM treatment. Best-corrected visual acuity (BCVA) and 3D volumetric high-definition optical coherence tomography (OCT) imaging were preoperatively acquired. Six months after the surgery, BCVA, OCT imaging, and RS measured by MP were assessed. For the OCT parameters, we analyzed both the full-macular and the ganglion cell layer complex (GCC) thicknesses. The MP parameters tested were 44 points covering 20 central degrees (6 mm), with direct correspondence with the nine sectors of the OCT-ETDRS map. This approach enables the direct topographic correlation between the structure and functional measurements. The OCT and MP exam measurements were also performed in 43 eyes of age-matched healthy controls. Correlations between BCVA, RS, and OCT parameters were examined. RESULTS:  All patients exhibited a substantial improvement in visual acuity following surgery. The RS parameters were significantly lower in patients compared to the controls. The full-macular thickness measurements were thicker than controls preoperatively and significantly reduced postoperatively; however, remaining significantly higher than controls, in the 4 inner sectors, at the fovea and for the average macular thickness. Preoperative GCC measurements were higher than those in controls. There was a significant reduction in GCC thickness in all sectors postoperatively, especially in the outer sectors, as well as in the average macular thickness. A positive correlation was found between full-macular and GCC thickness and RS postoperatively in several sectors. CONCLUSIONS: Our results demonstrate that ERM peeling can improve visual acuity in the postoperative period. However, RS may not fully restore, remaining significantly lower when compared to the controls. Both full-macular and GCC thickness measurements were reduced 6 months after surgery. However, significant thinning of the GCC thickness was observed when compared to the normal control eyes, indicating the occurrence of some degree of ganglion cell layer atrophy. We have demonstrated significant correlations among various OCT thickness parameters, particularly for GCC measurements. We believe that GCC integrity may play an important role in visual function after ERM surgery, and that MP may help better understand the correlations between structural and functional findings following ERM surgery.

Relationship between automated choroidal thickness measurements and retinal sensitivity using microperimetry in patients with myopia and different stages of myopic maculopathy.

PURPOSE: To assess the relationship between macular choroidal thickness (CT) measurements and retinal sensitivity (RS) in eyes with myopia and different stages of myopic maculopathy. METHODS: A masked, cross-sectional, and consecutive study involving patients with emmetropia/myopia (control group) and high myopia (HM) eyes. Automated choroidal thickness (CT) and manual outer retinal layer (ORL) thickness were acquired using swept-source optical coherence tomography, while retinal sensitivity (RS) assessed by microperimetry (MP3) in all regions of the macular Early Treatment Diabetic Retinopathy Study (ETDRS) grid. Comparisons were made between groups, and correlations were performed among these measurements, demographic and ocular parameters and myopic maculopathy classification. RESULTS: A total of 37 (74 eyes) patients were included in the study. The mean age was 39 ± 13 years, and 28 patients (76%) were female. HM eyes exhibited inferior best-corrected visual acuity and a more advanced myopic maculopathy classification compared to the control group. The mean macular CT were 255 and 179 µm in the control and HM eyes (P < 0.001), respectively. In the HM eyes, superior ETDRS region presented the greatest values. Mean RS in control and HM groups was 28 and 24 dB (P = 0.001), respectively. Inner temporal followed by superior, were the regions of higher RS. Mean ORL thickness was 83 and 79 µm (P < 0.001), in the control and HM groups, respectively. The inner temporal ETDRS region presented the thickest measure. CT correlated significantly with RS (r = 0.41, P < 0.001) and ORL thickness, (r = 0.58, P < 0.001), which also correlated with RS (r = 0.40, P < 0.001). Spherical equivalent, axial length and myopic maculopathy stage were the parameters that most correlated with CT, RS and ORL thickness. For every 100 µm increase in thickening of CT there was an average increase of 3.4 µm in ORL thickness and 2.7 dB in RS. Myopic maculopathy classification demonstrated influence only with CT. CONCLUSION: Myopia degree is related to ORL and choroidal thinning and deterioration of retinal sensitivity in some ETDRS regions of the macula. Choroidal thinning is associated to with a decline of retinal sensitivity, thinning of ORL, and worsening of myopic maculopathy classification, so new treatments are necessary to prevent myopia progression.

Reduction of foveal sensitivity in diabetic macular edema with visual acuity 20/20.

OBJECTIVE: To compare foveal sensitivity in eyes with and without diabetic macular edema, with 20/20 visual acuity. METHODS: Non-experimental, comparative, prospective, cross sectional study in eyes with and without retinopathy and focal macular edema, with 20/20 visual acuity. The sample was divided in 3 groups: (1) non-diabetic subjects, (2) diabetics without retinopathy, and 3) diabetics with non-proliferative retinopathy and clinically significant macular edema. Median foveal sensitivity was compared between groups (Kruskal Wallis test). RESULTS: 86 eyes (28 in group 1, 26 in group 2 and 32 in group (3). Medians shown a statistical difference between groups (p = 0.001). Median foveal sensitivity was significantly lower in group 3 than in group 1 (p = 0.001) and than in group 2 (p = 0.03). Median foveal sensitivity did not differ between groups 1 and 2 (p = 0.10). CONCLUSION: Foveal sensitivity in diabetic macular edema and visual acuity 20/20 is lower in eyes with center sparing clinically significant macular edema and 20/20 visual acuity. The prognostic value of this dysfunction requires evaluation, in order to learn whether early treatment is required in these eyes.

OBJETIVO: Comparar la sensibilidad foveal en ojos con y sin edema macular diabético, con agudeza visual 20/20. MÉTODO: Estudio observacional, comparativo, transversal y prospectivo, en ojos con y sin retinopatía y edema macular focal, con agudeza visual 20/20. La muestra se dividió en tres grupos: 1) sujetos sin diabetes, 2) diabéticos sin retinopatía, y 3) diabéticos con retinopatía diabética no proliferativa y edema macular focal. Se compararon las medianas de la sensibilidad foveal entre grupos mediante la prueba de Kruskal-Wallis. RESULTADOS: Se evaluaron 86 ojos (28 del grupo 1, 26 del 2 y 32 del 3). La comparación de medianas mostró una diferencia significativa entre grupos (p = 0.001). La sensibilidad foveal fue significativamente menor en el grupo 3 que en el grupo 1 (p = 0.001) y que en el grupo 2 (p = 0.03). La mediana de la sensibilidad foveal no difirió entre los grupos 1 y 2 (p = 0.10). CONCLUSIÓN: La sensibilidad foveal en el edema macular diabético con agudeza visual 20/20 es menor en ojos con edema macular clínicamente significativo sin engrosamiento del centro de la mácula y agudeza visual 20/20. Determinar el valor pronóstico de esta disfunción requiere una evaluación adicional para identificar si se necesita tratamiento temprano en estos ojos.

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.