Differing Associations between Optic Nerve Head Strains and Visual Field Loss in Normal- and High-Tension Glaucoma Subjects

Purpose: To study the associations between optic nerve head (ONH) strains under intraocular pressure (IOP) elevation with retinal sensitivity in glaucoma subjects. Design: Clinic based cross-sectional study. Participants: 229 subjects with primary open angle glaucoma (subdivided into 115 high tension glaucoma (HTG) subjects and 114 normal tension glaucoma (NTG) subjects). Methods: For one eye of each subject, we imaged the ONH using spectral-domain optical coherence tomography (OCT) under the following conditions: (1) primary gaze and (2) primary gaze with acute IOP elevation (to approximately 33 mmHg) achieved through ophthalmodynamometry. A 3-dimensional (3D) strain-mapping algorithm was applied to quantify IOP-induced ONH tissue strain (i.e. deformation) in each ONH. Strains in the pre-lamina tissue (PLT) and the retina, the choroid, the sclera and the lamina cribrosa (LC) were associated (using linear regression) with measures of retinal sensitivity from the 24-2 Humphrey visual field test (Carl Zeiss Meditec, Dublin, CA, USA). This was done globally, then locally according to the regionalization scheme of Garway-Heath et al. Main Outcome Measures: Associations between ONH strains and values of retinal sensitivity from visual field testing. Results: For HTG subjects, we found that (1) there were significant negative linear associations between ONH strains and retinal sensitivity (p<0.001) (on average, a 1% increase in ONH strains corresponded to a decrease in retinal sensitivity of 1.1 dB), (2) high strain regions co-localized with anatomically-mapped regions of high visual field loss, (3) the strongest negative associations were observed in the superior region and in the PLT. In contrast, for NTG subjects, no significant associations between strains and retinal sensitivity were observed except in the supero-temporal region of the LC. Conclusion: We found significant negative associations between IOP-induced ONH strains and retinal sensitivity in a relatively large glaucoma cohort. Specifically, HTG subjects who experienced higher ONH strains were more likely to exhibit lower retinal sensitivities. Interestingly, this trend was in general less pronounced in NTG subjects, which could suggest a distinct pathophysiology between the two glaucoma subtypes.

The Impact of Cataract Surgery on Contrast Visual Acuity and Retinal Sensitivity in Patients with Retinitis Pigmentosa

Purpose. To determine the effects of cataract surgery on contrast visual acuity and retinal sensitivity in patients with retinitis pigmentosa. Methods. Retinal sensitivity and contrast visual acuity were determined by microperimetry (MAIA) and contrast sensitivity acuity tester (CAT-CP), respectively, before and after cataract surgery. The significance of the correlations between visual acuity, retinal sensitivity, contrast visual acuity, improvements after surgery, and macular structure before and after cataract surgery was determined. Results. Retinal sensitivity and contrast visual acuity were significantly improved after cataract surgery. The correlations among postoperative visual acuity, postoperative retinal sensitivities, and preoperative ellipsoid zone length were significant. The postoperative retinal sensitivity of the central 10° and the ellipsoid zone length was particularly significantly correlated. Preoperative contrast visual acuity and the amount of improvement and preoperative retinal sensitivity and the amount of improvement were significantly negatively correlated. The contrast visual acuity under both the 100% and 10% photopic and mesopic conditions improved significantly after cataract surgery. Conclusions. Cataract surgery in retinitis pigmentosa patients with preserved ellipsoid zones significantly improved retinal sensitivity and contrast visual acuity. Cataract surgery can be expected to improve retinal sensitivity and contrast visual acuity under various conditions, even if preoperative visual parameters are low, as long as the ellipsoid zone is preserved.

Estimation of current and post-treatment retinal function in chronic central serous chorioretinopathy using artificial intelligence

Refined understanding of the association of retinal microstructure with current and future (post-treatment) function in chronic central serous chorioretinopathy (cCSC) may help to identify patients that would benefit most from treatment. In this post-hoc analysis of data from the prospective, randomized PLACE trial (NCT01797861), we aimed to determine the accuracy of AI-based inference of retinal function from retinal morphology in cCSC. Longitudinal spectral-domain optical coherence tomography (SD-OCT) data from 57 eyes of 57 patients from baseline, week 6–8 and month 7–8 post-treatment were segmented using deep-learning software. Fundus-controlled perimetry data were aligned to the SD-OCT data to extract layer thickness and reflectivity values for each test point. Point-wise retinal sensitivity could be inferred with a (leave-one-out) cross-validated mean absolute error (MAE) [95% CI] of 2.93 dB [2.40–3.46] (scenario 1) using random forest regression. With addition of patient-specific baseline data (scenario 2), retinal sensitivity at remaining follow-up visits was estimated even more accurately with a MAE of 1.07 dB [1.06–1.08]. In scenario 3, month 7–8 post-treatment retinal sensitivity was predicted from baseline SD-OCT data with a MAE of 3.38 dB [2.82–3.94]. Our study shows that localized retinal sensitivity can be inferred from retinal structure in cCSC using machine-learning. Especially, prediction of month 7–8 post-treatment sensitivity with consideration of the treatment as explanatory variable constitutes an important step toward personalized treatment decisions in cCSC.

Predicting Retinal Sensitivity Using Optical Coherence Tomography Parameters in Central Serous Chorioretinopathy

Purpose To predict the change of retinal sensitivity using optical coherence tomography (OCT) parameters in eyes with central serous chorioretinopathy (CSC). Methods Twenty-three eyes of 23 patients with CSC were enrolled. Retinal sensitivity was measured twice with a microperimetry in all examined eyes. OCT measurement was simultaneously conducted. The relationship between retinal sensitivities and the thicknesses of i) retinal nerve fiver layer + ganglion cell layer (RNFL+GCL), ii) inner nuclear layer (INL) iii) outer nuclear layer (ONL) and iV) serous retinal detachment height (SRDH) were investigated in a point-wise manner. We also investigated the association between the change of retinal sensitivity and OCT parameters at baseline. Results The mean age of participants was 49.8 ± 10.7 years. The mean SRDH was significantly lower (p<0.001) and the mean retinal sensitivity (p<0.001) was significantly higher in the 2nd examination compared to the 1st measurements, however LogMAR visual acuity (VA) was not significantly different between the two measurements (p=0.063). LogMAR VA was associated with retinal sensitivity both in the 1st and 2nd measurements (p<0.001). The retinal sensitivity in the 2nd examination was significantly correlated with retinal sensitivity, RNFL+GCL, INL, ONL, SRDH in the 1st examination and the improvement of SRDH. Conclusions Retinal sensitivity was associated with retinal structure in eyes with CSC; these parameters were useful to predict the change of visual function before the treatment.

Detecting Diabetic Retinal Neuropathy Using Fundus Perimetry

Fundus perimetry is a new technique for evaluating the light sense in the retina in a point-to-point manner. Light sense is fundamentally different from visual acuity, which measures the threshold for discriminating and perceiving two points or lines, called the minimum cognoscible. The quality of measurement of retinal sensitivity has dramatically increased in the last decade, and the use of fundus perimetry is now gaining popularity. The latest model of fundus perimetry, MP-3, can be used for a wide range of measurements and has an advanced eye tracking system. High background illumination enables accurate measurement of mesopic retail sensitivity. Recent investigations have shown that neuronal damage precedes vascular abnormalities in diabetic retinopathy. The loss of retinal function has also been reported prior to morphological changes in the retina. In this review, the importance of measuring retinal sensitivity to evaluate visual function in the early stages of diabetic retinopathy was discussed. The usefulness of retinal sensitivity as an outcome measure in clinical trials for treatment modalities is also presented. The importance of fundus perimetry is promising and should be considered by both diabetes researchers and clinical ophthalmologists.

Association Between Retinal Sensitivity and the Presence of Quiescent Choroidal Neovascularization in Pachychoroid Diseases

This study was conducted to examine retinal sensitivity (RS) in eyes with pachychoroid diseases and to analyze its association with the presence or absence of quiescent choroidal neovascularization (CNV), that can be protective against retinal dysfunction or atrophy in other macular diseases such as age-related macular degeneration. A total of 12 eyes of 12 patients aged ≥45 years having the characteristic findings of central serous chorioretinopathy but not presenting any exudative changes were included in this study. Choroidal vascular hyper permeability (CVH) was identified by indocyanine green angiography, and the presence or absence of CNV was evaluated by optical coherence tomography angiography. RS at 68 points was examined by microperimetry. The average RS corresponding to within and outside CVH was compared. The association between the difference in RS and the presence or absence of CNV was also analyzed. CNV was detected in six eyes (50%). In eyes without CNV, the RS within CVH was similar compared with that outside CVH. However, in eyes with CNV, the RS within CVH was significantly decreased compared with that outside CVH. Multiple regression analysis revealed the presence of CNV as an independent factor associated with RS. In eyes with pachychoroid diseases, RS decreased within the CVH area under the coexistence of nonexudative CNV.

Analysis of retinal sensitivity between acute and recurrent central serous chorioretinopathy assessed by microperimetry

Purpose To evaluate retinal sensitivity of macular region between acute and recurrent central serous chorioretinopathy (CSC) using microperimetry. Methods A retrospective observational study. Twenty-five eyes of 25 subjects who were diagnosed as either acute or recurrent CSC without any previous treatment were included in this study. All subjects underwent complete ophthalmological examinations including the central retinal thickness (CRT) using spectral domain OCT and the retinal sensitivity assessments of macular region by microperimeter MP-3. The mean global macular sensitivity (GMS) from 64 loci in the 20° central macular area and local macular sensitivity (LMS) from test locations in affected region of SRD were analysed. Results Twelve eyes of 12 subjects with acute CSC (Group A) and 13 eyes of 13 subjects with recurrent CSC (Group R) were enrolled. The clinical parameters, including age, duration, mean LogMAR best-corrected visual acuity and CRT, were not statistically significant (p>0.05) between Group A and Group R. There were significant differences in GMS and LMS between the two groups. Compared with group A (24.9±1.6dB), the mean GMS of group R was significantly (p<0.05) lower (23.0±2.0dB). In addition, the mean LMS of group R (19.9±2.3dB) was also significantly lower (p<0.05) compared with group A (21.8±2.1dB). Conclusion Eyes with recurrent CSC often show worse retinal function in focal affected macular areas than acute disease. Macular microperimetry analysis may deepen our understanding of CSC natural history and influence decision-making in clinical practice.

Evaluation of retinal sensitivity and microstructure in areas of capillary nonperfusion of eyes with branch retinal vein occlusion

Background To evaluate macular microstructure alterations in the parafoveal nonperfusion areas of eyes with branch retinal vein occlusions (BRVO), and to investigate their impact on retinal sensitivity. Methods This was a cross-sectional study including thirteen BRVO patients with parafoveal capillary nonperfusion areas (NPA). Multiple modalities including microperimetry, optical coherence tomography angiography, and optical coherence tomography were performed to measure retinal sensitivity and thickness, and to identify the microstructure changes and perfusion status. Results The retinal sensitivity and thickness in the NPA were significantly lower than those in the perfusion areas (PA) (P = 0.001, P = 0.003). Microstructure changes, including disorganization of the retinal inner layers (DRIL), disruption of the outer retinal layers, and cysts were more frequently observed in NPA (P = 0.002, P = 0.018, P = 0.068). Within NPA, the retinal sensitivity of areas with DRIL, and outer retinal layers disruption was significantly lower than that of the areas without DRIL (P = 0.016), and with intact outer retinal layers (P < 0.001), respectively. 1dB increase in retinal sensitivity was correlated with 2.2 μm (95 % confidence interval, 1.71–2.7) increase of the thickness (P < 0.001). The retinal sensitivity was significantly lower at points with both DRIL and outer retinal layers disruption than at the points with DRIL or outer retina layers disruption alone (P = 0.001, P = 0.001). Conclusions Alterations in the macular microstructure are associated with ischemia, especially DRIL. DRIL and outer retinal layers disruption are imaging features that have important implications for local retinal sensitivity in the ischemic areas, and where the microstructure of both inner and outer retinal layers is disrupted the function is further destructed.