MP-1 Microperimeter Research Articles

The effect of pleoptic treatment on the stability of visual fixation in children and adolescents with amblyopia of various degrees

This study assesses the effect of pleoptic treatment on the stability of visual fixation in children and adolescents with amblyopia of various degrees. The effect of the treatment in 35 children (35 eyes) with amblyopia of various degrees was evaluated using the MP-1 Microperimeter. The stability was determined by two criteria - number of fixation point hits in the 2° zone and the width of the field of fixation. Children underwent a standard course of treatment. There was an improvement in the stability of visual fixation after treatment. The number of fixation point hits in the 2° zone increased from 44.8±4.1% to 52.6±3.8%. At the same time, the width of the field of fixation after treatment decreased from 6.5±0.7° to 5.2±0.5°. Visual acuity with correction in children with amblyopia correlates with the number of fixation point hits in the 2° zone (direct high correlation "+0.7") and width of the field of fixation (inverse high correlation "-0.7") both before and after the treatment. Stabilization of visual fixation was observed in patients with amblyopia of varying degrees after the pleoptic treatment.

Macular Sensitivity Endpoints in Geographic Atrophy: Exploratory Analysis of Chroma and Spectri Clinical Trials

To assess different microperimetry (MP) macular sensitivity outcome measures capturing functional deterioration in eyes with geographic atrophy (GA) secondary to age-related macular degeneration (AMD). Patients were included from 2 identically designed, phase III, double-masked, randomized controlled clinical trials, Chroma (NCT02247479) and Spectri (NCT02247531). Patients enrolled were aged ≥ 50 years with bilateral GA and no evidence of previous or active neovascular AMD. Patients were randomized 2:1:2:1 to receive through 96 weeks intravitreal lampalizumab 10 mg every 4 weeks (LQ4W), every 6 weeks (LQ6W), or corresponding sham procedures. For this study, mesopic macular sensitivity of the central 20° was assessed using MP-1 microperimeter at selected sites. Two exploratory endpoints were developed, namely perilesional sensitivity (average of points adjacent to absolute scotomatous points) and responding sensitivity (average of all nonscotomatous points; > 0 dB at baseline) by using customized masks for each patient. These were compared with conventional MP endpoints (mean macular sensitivity and number of absolute scotomatous points). Of 1881 Chroma and Spectri participants, 277 agreed to participate in the present study. Of these, 197 (LQ4W, n=63; LQ6W, n=68; pooled sham, n=66) had reliable MP results. Enlargement of GA lesion area by approximately 2 mm2/year across treatment groups was accompanied by deterioration in all MP parameters. There was no difference in worsening of macular sensitivity or absolute scotomatous points among treatment groups. Perilesional and responding sensitivities showed greater decline over time than mean macular sensitivity. Change in GA lesion area at week 48 showed better correlation with perilesional sensitivity (r=-0.17) and responding sensitivity (r=-0.20) than mean macular sensitivity (r=-0.03), while the correlation was highest with the number of absolute scotomatous points (r=0.37). Perilesional or responding macular sensitivity measured by MP should be considered more sensitive endpoints than mean macular sensitivity for monitoring functional decline over time in GA. Although perilesional, responding, and mean macular sensitivity had weak correlation with GA lesion area, the number of absolute scotomatous points may provide additional information on the anatomic/functional correlation. Proprietary or commercial disclosure may be found after the references.

Microperimetry in Foveal Sparing Atrophic Late-Onset Retinal Degeneration.

To understand the baseline and longitudinal microperimetry (MP) characteristics in foveal sparing atrophic Late-Onset Retinal Degeneration (L-ORD). Prospective, cross-sectional, longitudinal study in which patients from the retina clinics of two academic teaching hospitals were included. Mesopic microperimetry was performed using a Nidek MP-1 micro-perimeter. Mean total, foveal, inner ring, and outer ring sensitivities were analyzed. A total of 20 eyes from 10 patients had baseline data. The subset of 10 eyes from 5 patients had follow-up data. The mean baseline macular sensitivity was 10.02 dB (+/- 5.26) with findings showing symmetry between both eyes. In the follow-up cohort, there was a significant loss of outer ring (0.83 dB per year, p= 0.0001), inner ring (0.67 dB per year, p=0.034), and foveal sensitivity (0.92dB loss per year, p= 0.015), while the mean sensitivity decreased significantly (0.66 dB per year, p = 0.0008) at 4-year follow-up. The drop in mean sensitivity was associated with significant increases in the number of deep scotoma points (6.20, p=0.037) and a decrease in the number of normal points (-6.30, p=0.022). Microperimetry is a useful tool for macular function follow-up to measure disease progression in L-ORD.

Binocularity Principles of PRL Development in Patients With Macular Disease.

PurposeWe tested the hypothesis that binocularity requirements for correspondence play a role in establishing the preferred retinal locus (PRL) in macular degeneration.MethodsMonocular PRL locations in 202 eyes of 101 patients with macular degeneration (79 ± 10 years) were recorded with the MP1 microperimeter. Corresponding PRLs were those with similar polar angle and distance from former fovea in the better eye (BE) and the worse eye (WE).ResultsOn average, the PRL in the BE was in the foveal proximity at 1.1 ± 0.99 degrees for 55 patients (foveal-driven PRL) and eccentrically at 6.9 ± 3.4 degrees for 46 patients with central lesions involving the fovea (peripheral-driven PRL). For the foveal-driven PRL group, the PRL in the BE was not affected by the status of the WE. In 100% of cases, the monocular PRL in the WE was in a corresponding location either on functioning retina or onto the lesion, or would fall onto the lesion during binocular viewing. For the peripheral-driven PRL group, the PRL location depended on the lesion size in both eyes to maximize correspondence and/or the function of peripheral vision during binocular viewing. In this group, PRL correspondence status was different for those with equal, unequal, or extensive lesions in both eyes.ConclusionsBinocularity requirements for correspondence play an important role in determining the PRL location. We formulated two principles based on whether the BE has foveal sparing (foveal-driven PRL) or central lesions affecting the fovea (peripheral-driven PRL). The PRL should be evaluated in the framework of binocular viewing.

The location of eccentric fixation point in patients with central scotomas of various origin

Aim to study the predominant localization of the eccentric fixation point in various types of macular pathology accompanied by the presence of a central scotoma.
 Material and methods. 94 eyes (90 people) with various macular pathologies leading to loss of central vision were examined. Fixation was recorded on several devices: an MP-1 and MP-3 microperimeter (Nidek Technologies, Italy) and a MAIA microperimeter (СenterVue, USA). To visualize and register the presence of macular pathology, all patients underwent optical coherence tomography using a Stratus OCT 3000 device (Carl Zeiss Meditec Inc., USA) and Spectralis (Heidelberg Engineering, Germany).
 Results. The study revealed that in most cases the preferred retinal locus is positioned in the upper and upper-left sector around scotoma, regardless of the etiology.
 Conclusion. The preferred retinal locus in most cases is located in the upper-left area of the retina near the central scotoma, the projection of which is in the lower-left side of the visual field. Knowing the preferred retinal locus, a doctor can more successfully adapt a patient with the absence of central vision.

Macular Structure-Function Relationships of All Retinal Layers in Primary Open-Angle Glaucoma Assessed by Microperimetry and 8 × 8 Posterior Pole Analysis of OCT.

Purpose: The aim of this study is too correlate the sensitivity and thickness values of intraretinal layers at macula in healthy eyes and primary open-angle glaucoma (POAG) eyes. Methods: The thickness of different intraretinal segmentations was estimated by means of optical coherence tomography (OCT) Spectralis (Heidelberg, Engineering, Inc., Heidelberg, Germany) with the posterior pole analysis program 8 × 8 in 91 eyes from 91 patients (60 with glaucoma and 31 healthy patients). Macular sensitivity was also measured with an MP-1 microperimeter (Nidek Instruments, Inc Padova, Italy) with a customized, 36-stimulus pattern adjusted to an anatomical correspondence with the OCT grid. Correlations were calculated by using Spearman’s rho and the results were represented in color maps. Results: Significant structure–function correlations were much more frequent in the glaucoma group than in control group. In general terms, associations were positive for inner retinal layers but negative correlations were also found for the inner nuclear layer and outer retinal layer in glaucoma. Conclusions: In general terms, significant structure–function correlations for different intraretinal layers are higher and wider in POAG eyes than in healthy eyes. Inner and outer retinal layers behave differently in terms of the structure–function relationship in POAG as assessed by microperimetry and OCT.

Fixation stability improvement after occlusion treatment for severe amblyopia.

To investigate the improvement of fixation stability of severe amblyopia with traditional patching treatment by the MP-1 microperimeter. Eighteen patients with severe unilateral amblyopia were enrolled and received prescribed 6h per day of patching of the fellow eye with optical correction if needed. Fixation test was performed on eighteen severe unilateral amblyopia patients by the MP-1 microperimeter in baseline, 3-month and 6-month after treatment. The bivariate contour ellipse area (BCEA, deg2) was used to quantify fixation stability. The RMANOVA showed that significant differences were found in best-corrected visual acuity (BCVA) between amblyopia eyes/fellow eyes (AE/FE) group (F = 113.52, p < 0.001) and among follow-up time (F = 74.684, p < 0.001). Moreover, a significant interaction could be found between AE/FE group and follow-up time (baseline/3-month/6-month, F = 60.189,p < 0.001). Post hoc analysis by Bonferroni showed significant improvement of BCVA in AE at 3-month (p < 0.001) and 6-month (p < 0.001), compared to baseline, and also significant between 3-month and 6-month (p = 0.002). The RMANOVA showed that significant differences were found in BCEA between AE/FE group (F = 8.432, p = 0.006) and among follow-up time (F = 10.431, p = 0.003). Moreover, a significant interaction could be found between AE/FE group and follow-up time (F = 9.099, p = 0.005). The mean BCEA of AE changed from 13.14 ± 17.97 deg2 at baseline to 6.03 ± 7.27 deg2 at 3-month (p = 0.084) and 3.38 ± 6.40 deg2 at 6-month (p = 0.018). No significant difference of BCEA in fellow eyes was found during the follow-up period (between baseline and 3-month: p = 0.230; between baseline and 6-month: p = 0.692. 0.89 ± 1.02, 0.58 ± 0.40, and 0.03 ± 0.04deg2 for baseline, 3-month and 6-month, respectively). No significant correlation could be found between BCEA and BCVA of AE, both in enrollment and follow-up (p > 0.05). The fixation stability in theamblyopic eyes is significantly worse than that of thefellow eyes in patients withunilateral severeamblyopia. The fixation stability became better after 6-month occlusion treatment, but the change offixation stabilitywasnot correlated with visual acuity improvement. These quantitative results highlight the importance of fixation in the mechanism of amblyopia.

Fixation Characteristics of Severe Amblyopia with Eccentric Fixation and Central Fixation Assessed by the MP-1 Microperimeter

ABSTRACT Objectives To investigate the fixation patterns in severe amblyopia with eccentric or central fixation by the MP-1 microperimeter. Design Fixation test was performed on 38 patients with severe amblyopia using the MP-1 microperimeter, 20 patients with eccentric fixation (EF group), and 18 patients with central fixation (CF group). Fixation location and fixation stability were quantified by preferred fixation eccentricity and bivariate contour ellipse area (BCEA, deg2) respectively. Comparisons of BCEA between amblyopic and fellow eyes (FE) in both groups and between amblyopic eyes (AE) in both groups were analyzed. Linear regression analysis was used to investigate the risk factors for fixation instability in patients with eccentric fixation. Results In EF group, the BCEA of AE was 14.68 ± 19.21 deg2, which was significantly larger than that of FE (1.294 ± 1.840, F = 9.243, p = .007). Linear regression analysis showed that only preferred fixation eccentricity (β = 6.536, 95% CI: 2.665 ~ 10.406, p < .005) was correlated with BCEA of AE. The BCEA of AE in the EF group was significantly larger than that of AE in the CF group (4.95 ± 3.44 deg2, t = 2.227,p < .05), although the BCVA was not significantly different between two groups (t = 0.129, p = .898). Conclusions The fixation ability in amblyopia with eccentric fixation was found to be significantly worse than those with central fixation and preferred fixation eccentricity was the only predictor for the instability. MP-1 is an effective tool to quantify fixation features for diagnosis and follow-up of eccentric amblyopia patients.

Location and stability of the preferred retinal locus in native Persian‐speaking patients with age‐related macular degeneration

ABSTRACT Clinical relevance The findings of this study can be used in the selection of the preferred retinal locus to establish better rehabilitation services such as eccentric viewing training for patients with age‐related macular degeneration. Background The aim of this study was to determine the characteristics of the preferred retinal locus in native Persian‐speaking patients with age‐related macular degeneration. Methods In this non‐interventional case series, all patients with a diagnosis of age‐related macular degeneration referred to the Retina Clinic of the Rassoul Akram Hospital, Tehran, Iran, were evaluated. The fixation characteristics were evaluated monocularly using the MP1 microperimeter (Nidek Technologies, Padua, Italy). Optical coherence tomography was used to determine the location of the central fovea. The images were overlaid and the preferred retinal locus‐fovea distance was measured using Image J software. Results Fifty‐one eyes of 35 patients with a mean age of 73.8 ± 7.7-years were evaluated in this study. Inferior‐field, left‐field, central‐field, right‐field, and superior‐field preferred retinal locus were detected in 49 per cent, 33.3 per cent, 7.8 per cent, 5.9 per cent, and 3.9 per cent of the subjects, respectively. Fixation was stable in 70.6 per cent, relatively unstable in 15.7 per cent, and unstable in 13.7 per cent of the participants. Significant differences were not found in the mean values of logMAR visual acuity between different fields of the preferred retinal locus after Bonferroni correction (p = 0.031). Analysis of co‐variance showed no significant difference in mean sensitivity values between different locations of the preferred retinal locus (p = 0.07). The mean preferred retinal locus‐fovea distance was not significantly different between different fields of the preferred retinal locus (p = 0.063). Conclusions Native Persian‐speaking patients with central scotoma secondary to age‐related macular degeneration place their self‐selected preferred retinal locus most frequently in the inferior and left visual field, which would result in scotoma displacement to the superior and right visual field. Fixation stability was statistically similar in different locations of preferred retinal locus, but it improved with decreasing the preferred retinal locus‐fovea distance.

Evaluating Reading Performance in Different Preferred Retinal Loci in Persian-Speaking Patients with Age-Related Macular Degeneration.

Purpose:To evaluate reading performance in different preferred retinal loci (PRLs) using a Persian version of a Minnesota Low Vision Reading (MNREAD) chart in Persian-speaking patients with age-related macular degeneration (AMD).Methods:In this cross-sectional study, 35 patients with AMD were assessed. The reading performance was investigated by the MNREAD chart without using low vision aids. The location of PRL was determined monocularly using an MP1 microperimeter (Nidek Technologies, Padua, Italy). The anatomical location of the fovea was determined using optical coherence tomography (OCT). Images were taken with the MP1 microperimeter, and Spectralis HRA-OCT device was processed using graphic software to determine the location of the PRL on the retina.Results:Thirty-five patients (51 eyes) with a mean age of 73.8 ± 7.7 years (range, 54–88 years) were assessed. Mean best corrected distance visual acuity (logMAR) was 0.65 ± 0.35 (range, 0.2–1.3). Mean levels of reading acuity (RA) (P = 0.009) and critical print size (CPS) (P = 0.015) were significantly different in different locations of PRL. Average scores of maximum reading speed (MRS) (P = 0.058) and reading accessibility index (ACC) (P = 0.058) were not statistically significant in different locations of PRL. There was a positive correlation between PRL-fovea distance and RA (P < 0.001, r = 0.591) and CPS (P < 0.001, r = 0.614). Significant negative correlations were observed between PRL-fovea distance and MRS (P < 0.001, r = −0.519) and ACC (P < 0.001, r = −0.545).Conclusions:This study provides evidence for differences in the reading performance of Persian-speaking patients with AMD in different PRL locations. The average scores of all reading indices obtained in the right-field PRL are lower than those in other areas and are highly correlated with the PRL-fovea distance.

Effect of Disease Progression on the PRL Location in Patients With Bilateral Central Vision Loss.

PurposeTo investigate the effect of disease progression on the monocular preferred retinal locus (PRL) of the better eye (BE) and worse eye (WE) of patients with central vision loss.MethodsFifty-one patients with bilateral macular diseases were included. The monocular PRL was recorded for each eye (N = 102 eyes) with the MP-1 microperimeter in two visits that were 458 ± 249 days apart. For each eye and visit, the PRL distance from the former fovea, polar angle, and scotoma size were measured. The change in PRL location from visit 1 to visit 2 was evaluated with the differential map analysis.ResultsScotoma size increased significantly in both eyes. The PRL distance from the former fovea increased significantly from visit 1 to visit 2 in the BE, but not in the WE. The polar angle was relatively stable in both visits for the BE. The change in PRL location in the BE was predicted only by the PRL distance from the former fovea in visits 1 and 2, but not by polar angle or scotoma size. For the WE, the change in PRL location depended on the change in PRL location in the BE, rather than on measurements made on that eye.ConclusionsDisease progression affects monocular PRL location differently in the 2 eyes. The results suggest a recalibration of the oculomotor system with its reference at the PRL from the BE.Translational RelevanceThese findings are important for deciding the course of treatment and/or for developing rehabilitation techniques focusing on PRL relocation.

Rehabilitative effect of the patterned stimulation with MP1 microperimeter in homonymous hemianopia

Rehabilitative effect of the patterned stimulation with MP1 microperimeter in homonymous hemianopia

Eight-year multimodal follow-up of recurrent idiopathic acute exudative polymorphous vitelliform maculopathy

To describe and analyze clinical findings in a patient with recurrent idiopathic acute exudative polymorphous vitelliform maculopathy (AEPVM), followed in detail, and to propose the diagnostic and follow-up algorithm. Retrospective observational analysis. A young adult male patient diagnosed with idiopathic AEPVM who developed two relapses in a 12-month period eight years after the initial onset. Review of clinical charts, multimodal imaging, and electrophysiology findings. The patient repeatedly underwent complete ophthalmic examinations, including best-corrected visual acuity testing (BCVA), slit-lamp and fundus examinations; digital fundus photography, time-domain optical coherence tomography (OCT) in 2009 (Stratus OCT, Carl Zeiss Meditec, USA) and spectral-domain OCT in 2017-2018 (Spectralis-OCT, Heidelberg Engineering, Germany), together with fundus autofluorescence (FAF), fluorescein angiography (FA), and indocyanine green angiography (ICGA), all with HRA2 (Heidelberg Engineering, Germany); microperimetry (MP-1 microperimeter, Nidek, Japan). Laser flare photometry (Kowa FM-600, Japan) and electrophysiology testing were also performed. Clinical features of long-lasting recurrent idiopathic AEPVM, and diagnostic and follow-up algorithm in such rare cases. Case report of a 25-year-old male Caucasian patient with typical features of AEPVM, including serous neuroepithelial detachment with irregular retinal elevations, ophthalmoscopically resembling retinal folds, with subsequent subretinal accumulation of characteristic yellow-white vitelliform deposits. Features in this case rarely described, or even not yet reported, include indocyanine- and fluorescein-negative intraretinal cystic changes, optic disc hyperfluorescence on FA, serous retinal elevations mimicking retinal folds, increased choroidal thickness, lack of rapid visual recovery, and very slow anatomical improvement of the relapses. Bimonthly fundus autofluorescence evaluation together with SD-OCT were the most informative diagnostic methods, demonstrating the evolution of pathological signs. AEPVM may be a recurrent or even chronic condition with uncertain long-term visual outcomes. It may have variable clinical presentations depending on the stage of the disease, and both clinical manifestations and imaging features of different stages of the pathologic process may overlap. Patients should be made aware that visual improvement occurs very slowly, if at all. Bimonthly fundus autofluorescence evaluation together with SD-OCT should be recommended in such cases.

Reliability of colour perimetry to assess macular pigment optical density in age-related macular degeneration.

The aim of this study was to determine the intra-session repeatability and inter-examiner reproducibility of the colour perimetry technique when assessing in vivo macular pigment optical density in age-related macular degeneration patients. Age-related macular degeneration patients were classified into four groups: early age-related macular degeneration, intermediate age-related macular degeneration, atrophic age-related macular degeneration and neovascular age-related macular degeneration after undergoing fundus photography (TRC 50DX type IA) and spectral-domain optical coherence tomography analysis (Topcon 3D-2000). Central fixation was confirmed in all patients using the MP-1 microperimeter (Nidek, Padua, Italy). To analyse repeatability, one examiner obtained three consecutive macular pigment optical density measures with MonCV3 device (Metrovision, Perenchies, France). To study agreement between two observers, a second examiner performed another macular pigment optical density measurement in random order. Within-subject standard deviation, coefficient of variation, and intraclass correlation coefficient data were obtained. Fifty two (32 females and 20 males) consecutive age-related macular degeneration patients having a mean age of 71.5 ± 8.2 years were recruited. Six had early age-related macular degeneration, 25 had intermediate age-related macular degeneration, 10 had atrophic age-related macular degeneration and 11 had neovascular age-related macular degeneration. For repeatability, coefficient of variation values ranged from 22.3% (neovascular age-related macular degeneration) to 41.0% (atrophic age-related macular degeneration) and intraclass correlation coefficient values from 0.52 (intermediate age-related macular degeneration) to 0.79 (neovascular age-related macular degeneration). For agreement between two examiners, coefficient of variation values ranged from 20.1% (intermediate age-related macular degeneration) to 37.8% (neovascular age-related macular degeneration) and intraclass correlation coefficient values from 0.61 (neovascular age-related macular degeneration) to 0.80 (atrophic age-related macular degeneration). The reliability (intra-session repeatability and inter-examiner reproducibility) of colour perimetry technique to assess macular pigment optical density in age-related macular degeneration patients is only moderate. Thus, it cannot be recommended to be performed when evaluating and monitoring age-related macular degeneration patients in the daily clinic.

Correlation of retinal layer changes with vision gain in diabetic macular edema during conbercept treatment

BackgroundsTo assess the changes in individual retinal layer thickness and visual function associated with gains in visual acuity after an intravitreal conbercept injection in the diabetic macular edema (DME) on spectral domain optical coherence tomography (SD-OCT) and microperimetry during 1-year follow-up.MethodsRetrospective observational study. Twenty patients with clinically significant DME in the study eye were imaged by SD-OCT every 3 months and MP1 microperimeter in the third month while receiving anti-vascular endothelial growth factor (VEGF) (conbercept) treatment. In each patient, seven retinal layers were segmented in 98 scans covering a 6 mm × 6 mm area of the macula at baseline and during 1 year of treatment. An automatic, full-threshold microperimetry of the central field (10° × 10°, 40 stimulated points) with the MP1 microperimeter. Thickness and microperimetry changes were quantitatively measured and evaluated for their correlation with increases in visual acuity.ResultsAlthough thicknesses of the inner nuclear layer (INL) and the outer nuclear layer (ONL) were reduced the most after treatment (p < 0.05), decreases of the ganglion cell layer (GCL) (r = 0.591, p = 0.006) and inner plexiform layer (IPL) (r = 0.663, p = 0.001) in central subfield area was associated with best-corrected visual acuity (BCVA) gain, and had the best estimation of BCVA gain (adjust R2 = 0.544). Mean macular sensitivity in the central subfield was also well correlated with BCVA gain (r = 0.531, p = 0.016).ConclusionsNeural recovery occurred after the resolution of edema during conbercept treatment, due to the decreases in GCL and IPL associating with gains in vision and improved microperimetry.

Longitudinal Changes of Fixation Location and Stability Within 12 Months in Stargardt Disease: ProgStar Report No. 12

To investigate the natural history of Stargardt disease (STGD1) using fixation location and fixation stability. Multicenter, international, prospective cohort study. Fixation testing was performed using the Nidek MP-1 microperimeter as part of the prospective, multicenter, natural history study on the Progression of Stargardt disease (ProgStar). A total of 238 patients with ABCA4-related STGD1 were enrolled at baseline (bilateral enrollment in 86.6%) and underwent repeat testing at months 6 and 12. Outcome measures included the distance of the preferred retinal locus from the fovea (PRL) and the bivariate contour ellipse area (BCEA). After 12months of follow-up, the change in the eccentricity of the PRL from the anatomic fovea was-0.0014 degrees (95% confidence interval [CI],-0.27 degrees, 0.27 degrees; P= .99). The deterioration in the stability of fixation as expressed by a larger BCEA encompassing 1 standard deviation of all fixation points was 1.21 degrees squared (deg2) (95% CI,-1.23 deg2, 3.65 deg2; P=.33). Eyes with increases and decreases in PRL eccentricity and/or BCEA values were observed. Our observations point to the complexity of fixation parameters. The association of increasingly eccentric and unstable fixation with longer disease duration that is typically found in cross-sectional studies may be countered within individual patients by poorly understood processes like neuronal adaptation. Nevertheless, fixation parameters may serve as useful secondary outcome parameters in selected cases and for counseling patients to explain changes to their visual functionality.

HbA1c and retinal sensitivity in diabetics using microperimetry

PurposeThe purpose of this study was to determine the relationship between HbA1c values and retinal sensitivity at central 10° using the MP-1 microperimeter. MethodsA prospective study was carried out on 32 healthy subjects (control group) and 60 diabetic patients. The diabetic patients were divided into 2 groups. Group 1 comprised of 30 patients without diabetic retinopathy (DR) and group 2 had 30 patients with mild non-proliferative DR. A full-threshold microperimetry of the central 10° of retina (the macula) was performed on all subjects, utilizing 32 points with the MP-1. The relationship between light sensitivity and HbA1c value was calculated using linear regression analysis. ResultsTotal mean sensitivity at 10° for group 1 without DR, group 2 with mild NPDR and control group were 18.67±0.83, 17.98±1.42 and 19.45±0.34 (dB), respectively. There was a significant difference in total mean retinal sensitivity at 10° between the 3 groups (F(2,89)=18.14, p=0.001). A simple linear regression was calculated to predict HbA1c based on retinal sensitivity. A significant regression equation was found (F(1,90)=107.61, p=0.0001, with an R2 of 0.545). The linear regression analysis revealed that there was a 0.64dB decline in mean retinal sensitivity within the central 10° diameter with an increase of 1mmHg of HbA1c. ConclusionRetinal sensitivity at the central 10° of the macula is affected by changes in HbA1c values.

Fixation parameter test-retest repeatability of the worse eye in central field loss

ObjectivePatients with bilateral central field loss develop peripheral retinal loci (PRLs) in the functional eccentric retina. PRL characteristics and visual performance in the better-seeing eye (BE) of these patients have previously been reported. In this study, we determined the test-retest repeatability of fixation parameters, including fixation stability, PRL eccentricity, and PRL span in the worse-seeing eye (WE). DesignRetrospective consecutive case series. ParticipantsThirty-six patients with bilateral central field loss referred from the Toronto Western Hospital Retina Clinic, who had completed 2 consecutive fixation examinations on the same day. MethodsFixation stability was recorded using the Nidek MP-1 microperimeter (Nidek Technologies Srl., Padova, Italy). For each fixation recording, the following parameters were retrieved: (i) 68.2% bivariate contour ellipse area (BCEA), (ii) PRL span (major and minor axes of the BCEA), (iii) PRL meridian (polar angle), and (iv) PRL eccentricity. Test-retest repeatability for each parameter was assessed using Bland-Altman plots to determine 95% limits of agreement. ResultsThe mean difference between the fixation trial pairs and the 95% limits of agreement for fixation stability, PRL major axis, PRL minor axis, PRL meridian, and PRL eccentricity were 0.06 ± 0.47 log deg2, 0.05° ± 1.42°, 0.07° ± 0.63°, −0.44° ± 66.0°, and −0.23° ±1.56°, respectively. ConclusionsThe fixation parameters in the WE showed robust repeatability, comparable to that of the BE as determined from previous studies. The WE’s fixation repeatability should be considered in the interpretation of fixation outcome measures subsequent to treatment interventions.

Functional changes at the preferred retinal locus in subjects with bilateral central vision loss.

Subjects with bilateral central vision loss (CVL) use a retinal region called the preferred retinal locus (PRL) for performing various visual tasks. We probed the fixation PRL in individuals with bilateral macular disease, including age-related macular degeneration (AMD) and Stargardt disease (STGD), for localized sensitivity deficits. Three letter words at the critical print size were presented in the NIDEK MP-1 microperimeter to determine the fixation PRL and its radial retinal eccentricity from the residual fovea in 29 subjects with bilateral CVL. Fixation stability was defined as the median bivariate contour ellipse area (BCEA) from 3 fixation assessments. A standard 10-2 grid (68 locations, 2° apart) was used to determine central retinal sensitivity for Goldmann size II test spots. Baseline and follow-up supra-threshold screening of the fixation PRL for localized sensitivity deficits was performed using high density (0.2° or 0.3° apart) 0dB Goldmann size II test spots. Custom MATLAB code and a dual bootstrapping algorithm were used to register test-spot locations from the baseline and follow-up tests. Locations where the 0dB test spots were not seen on either test were labeled as micro-scotomas (MSs). Median BCEA correlated poorly with the radial eccentricity of the fixation PRL. Mean (±SD) sensitivity around the PRL from 10-2 testing was 4.93±4.73dB. The average percentage of MSs was similar for patients with AMD (25.4%), STGD (20.3%), and other etiologies of CVL (27.1%). The fixation PRL in subjects with bilateral CVL frequently includes local regions of sensitivity loss.

Macular Sensitivity Measured With Microperimetry in Stargardt Disease in the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) Study

New outcome measures for treatment trials for Stargardt disease type 1 (STGD1) and other macular diseases are needed. Microperimetry allows mapping of light sensitivity of the macula and provides topographic information on visual function beyond visual acuity. To measure and analyze retinal light sensitivity of the macula in STGD1 using fundus-controlled perimetry (microperimetry). This was a multicenter prospective cohort study. A total of 199 patients and 326 eyes with molecularly confirmed (ABCA4) STGD1 underwent testing with the Nidek MP-1 microperimeter as part of the multicenter, prospective Natural History of the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) study. Sensitivity of 68 retinal loci was tested, and the mean sensitivity (MS) was determined; each point was categorized as "normal," "relative," or "deep" scotoma. Mean sensitivity and the number of points with normal sensitivity, relative, or deep scotomas. Mean (SD) patient age was 34.2 (14.7) years, mean (SD) best-corrected visual acuity of all eyes was 47.8 (16.9) Early Treatment Diabetic Retinopathy Study letter score (approximately 20/100 Snellen equivalent), and mean MS of all eyes of all 68 points was 11.0 (5.0) dB. The median number of normal points per eye was 49 (mean [SD], 41.3 [20.8]; range, 0-68); abnormal sensitivity and deep scotomas were more prevalent in the central macula. Mean sensitivity was lower in the fovea (mean [SD], 2.7 [4.4] dB) than in the inner (mean [SD], 6.8 [5.8] dB) and outer ring (mean [SD], 12.7 [5.3] dB). Overall MS per eye was 0.086 dB lower per year of additional age (95% CI, -0.13 to -0.041; P < .001) and 0.21 dB lower per additional year of duration of STGD1 (95% CI, -0.28 to -0.14; P < .001). Longer duration of STGD1 was associated with worse MS (β = -0.18; P < .001), with a lower number of normal test points (β = -0.71; P < .001), and with a higher number of deep scotoma points (β = -0.70; P < .001). We found 11 eyes with low MS (<6 dB) but very good best-corrected visual acuity of at least 72 Early Treatment Diabetic Retinopathy Study letter score (20/40 Snellen equivalent). We provide an extensive analysis of macular sensitivity parameters in STGD1 and demonstrate their association with demographic characteristics and vision. These data suggest microperimetry testing provides a more comprehensive assessment of retinal function and will be an important outcome measure in future clinical trials.