Comparison of retinal layer intensity profiles from different OCT devices

En Face and Volumetric Comparison of Hypertransmission Defects Evaluated by Cirrus and Spectralis Optical Coherence Tomography

PURPOSE

To evaluate and compare en face and 3-dimensional (3-D) properties of hypertransmission defects (HTDs) between different optical coherence tomography (OCT) devices using OCT volumes and reconstructed en face images.

SETTINGS

Comparative diagnostic evaluation study.

METHODS

Thirty eyes with dry age-related macular degeneration (AMD) that underwent dense OCT macular volume scans with both the Spectralis (97 B-scans/volume; 2910 B-scans in total) and Cirrus OCT (128 B-scans/volume; 3840 B-scans in total) from the Amish Eye Study cohort were included in this analysis. HTD regions were labeled on each B-scan and reconstructed into en face and 3-D volume images. Properties of HTD volume were compared between the 2 devices.

RESULTS

The qualitative score of en face images for HTD was higher for the Cirrus compared to the Spectralis (P < .01). The quality of Spectralis en face images improved after preprocessing and reconstruction. The 2-D HTD area on en face obtained from 2-D projections of 3-D volume did not differ between devices (P = .478, ICC = 0.998; Jaccard index 0.721 ± 0.086). There was no difference in the number, volume, PALs, and surface areas of HTDs between devices in the volumetric analysis (all P ≥ .090). The signal intensity of HTD normalized by the mean choroidal signal intensity did not differ between devices (P = .861).

CONCLUSIONS

The visualization of HTD on en face images from Spectralis OCT could be enhanced through image processing. The equivalence in 3-D HTD parameters between the 2 devices suggests interchangeability for assessing these lesions in AMD.

Baseline imaging characteristics and early structural changes in macula on rhegmatogenous retinal detachment

Animal models have demonstrated that structural changes affect the macula during peripheral rhegmatogenous retinal detachment. This study aimed to assess photoreceptors, retinal and choriocapillaris perfusion in non-macula involving rhegmatogenous retinal detachment by analyzing en-face images from structural OCTA segmented at the ellipsoid zone (EZ) level, calculating (1) "normalized" reflectivity as a surrogate biomarker of photoreceptor damage (2) perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) (3) perfusion density of choriocapillaris (PDCC). Twenty-one eyes affected by macula-on rhegmatogenous retinal detachment (RRD) were enrolled at the University "G. d'Annunzio", Chieti-Pescara. The fellow unaffected eye was used as control. The mean age at the onset of RRD was 60.09 ± 10.22 (range 34-83). Compared with fellow eyes, we found lower EZ "normalized" reflectivity in macula-on (0.42 ± 0.15 in fellow eyes and 0.31 ± 0.09 in macula on p = 0.004). The affected eye was also characterized by impaired perfusion in SCP (17.26 ± 3.34% in macula on and 20.56 ± 3.62% in the fellow eye p = 0.004) and CC (50.21 ± 6.20% in macula on the eye and 57.43 ± 6.20% in the fellow eye p = 0.004). Macula-on rhegmatogenous retinal detachment has subclinical changes in photoreceptors, SCP, and CC. Future longitudinal studies should evaluate if early changes could impact post-operative macular function.

Pushing Retinal Imaging Forward: Innovations and Their Clinical Meaning - The 2022 Ophthalmologica Lecture

Retinal imaging has greatly expanded our understanding of various pathological conditions. This article presents a summary of the key points covered during the 2022 Ophthalmologica Lecture held at the Euretina Congress in Hamburg. The first part of the article focuses on the use of optical coherence tomography angiography to examine and comprehend the choroid in age-related macular degeneration (AMD). Subsequently, we delve into the discussion of the "postreceptor neuronal loss" theory in AMD, which was studied using en face structural optical coherence tomography (OCT). Following that, we explore pertinent findings obtained through cross-sectional OCT in retinal and optic nerve diseases, such as AMD, diabetic macular edema, pathologic myopia, central serous chorioretinopathy, and Leber's hereditary optic neuropathy.

Functional Optical Coherence Tomography for Intrinsic Signal Optoretinography: Recent Developments and Deployment Challenges

Intrinsic optical signal (IOS) imaging of the retina, also termed as optoretinogram or optoretinography (ORG), promises a non-invasive method for the objective assessment of retinal function. By providing the unparalleled capability to differentiate individual retinal layers, functional optical coherence tomography (OCT) has been actively investigated for intrinsic signal ORG measurements. However, clinical deployment of functional OCT for quantitative ORG is still challenging due to the lack of a standardized imaging protocol and the complication of IOS sources and mechanisms. This article aims to summarize recent developments of functional OCT for ORG measurement, OCT intensity- and phase-based IOS processing. Technical challenges and perspectives of quantitative IOS analysis and ORG interpretations are discussed.

Signal-carrying speckle in optical coherence tomography: a methodological review on biomedical applications

SIGNIFICANCE

Speckle has historically been considered a source of noise in coherent light imaging. However, a number of works in optical coherence tomography (OCT) imaging have shown that speckle patterns may contain relevant information regarding subresolution and structural properties of the tissues from which it is originated.

AIM

The objective of this work is to provide a comprehensive overview of the methods developed for retrieving speckle information in biomedical OCT applications.

APPROACH

PubMed and Scopus databases were used to perform a systematic review on studies published until December 9, 2021. From 146 screened studies, 40 were eligible for this review.

RESULTS

The studies were clustered according to the nature of their analysis, namely static or dynamic, and all features were described and analyzed. The results show that features retrieved from speckle can be used successfully in different applications, such as classification and segmentation. However, the results also show that speckle analysis is highly application-dependant, and the best approach varies between applications.

CONCLUSIONS

Several of the reviewed analyses were only performed in a theoretical context or using phantoms, showing that signal-carrying speckle analysis in OCT imaging is still in its early stage, and further work is needed to validate its applicability and reproducibility in a clinical context.

Challenges Associated With Ellipsoid Zone Intensity Measurements Using Optical Coherence Tomography

Translational Relevance

Qualitative evaluation of the ellipsoid zone band on optical coherence tomography is a valuable clinical tool for assessing photoreceptor structure, though more quantitative metrics are emerging. Awareness of the challenges involved in interpreting quantitative metrics is important for their clinical translation.

COMPARISON OF SPECTRALIS AND CIRRUS OPTICAL COHERENCE TOMOGRAPHY FOR THE DETECTION OF INCOMPLETE AND COMPLETE RETINAL PIGMENT EPITHELIUM AND OUTER RETINAL ATROPHY

PURPOSE

To evaluate and compare the detection of incomplete and complete retinal pigment epithelial and outer retinal atrophy (iRORA and cRORA) using Spectralis and Cirrus optical coherence tomography (OCT) devices.

METHODS

Subjects with late age-related macular degeneration were imaged on the same day with Spectralis and Cirrus OCT. Two, masked, independent, and experienced retina specialist graders evaluated each case for the presence of cRORA and iRORA lesions.

RESULTS

A significantly higher number of lesions were observed using Spectralis compared with Cirrus (239 vs. 226 and 223 vs. 209). Higher number of iRORA lesions were identified with Spectralis (105 vs. 90 and 96 vs. 82), and no significant difference was observed between devices for cRORA lesions (134 vs. 136 and 128 vs. 126). When considering the presence or absence of iRORA or cRORA, the agreement between devices for both graders was excellent for cRORA and good for iRORA.

CONCLUSION

Spectralis and Cirrus OCT identified a similar number of cRORA lesions, although more iRORA lesions could be detected with Spectralis OCT. These findings may have implications for developing acquisition protocols for trials based on the intended atrophy targets and highlight the importance of using a consistent OCT instrument across a study.

Outer retina dysfunction and choriocapillaris impairment in type 1 diabetes

To study the outer retina morpho-functional characteristics and the choriocapillaris (CC) features in type 1 diabetic (T1D) patients, with and without signs of diabetic retinopathy (NPDR and NoDR). Twenty-five NPDR and 18 NoDR eyes were imaged by Optical Coherence Tomography Angiography. Ellipsoid zone (EZ) “normalized” reflectivity and CC perfusion density parameters, as flow deficits number (FDn), flow deficit average area (FDa) and flow deficit percentage (FD%), were analysed. Multifocal electroretinogram (mfERG) response amplitude densities (RADs) were measured. Mean EZ “normalized” reflectivity, CC FDn and FD% values, were similar (p > 0.05) in both groups, FDa was significant greater (p > 0.05) in NPDR compared with NoDR eyes. MfERG-RADs were similar in both groups. NPDR eyes showed a significant (p < 0.05) linear correlation between RADs and both, CC FDa and FD%. The EZ “normalized” reflectivity was negatively correlated with CC FD% in NoDR eyes. In NPDR T1D eyes a significant relationship between abnormal outer retina functional responses and CC impairment was observed, while in NoDR eyes the photoreceptor reflectivity was correlated to CC abnormalities. The outer retina dysfunction in NPDR correlated to CC drop-out let hypothesize that the outer retinal elements are functionally impaired in proportion to the CC vascular supply deficit.

PHOTORECEPTOR DAMAGE IN DIABETIC CHOROIDOPATHY

PURPOSE

To investigate the relationship between choriocapillaris (CC) hypoperfusion and photoreceptor alterations in eyes with nonproliferative diabetic retinopathy (NPDR).

METHODS

In this prospective, observational, case-control study, 30 eyes (30 patients) with NPDR and 30 healthy eyes from 30 controls were enrolled at the University G. d'Annunzio, Chieti-Pescara, Italy. This study cohort underwent an ophthalmologic examination, including optical coherence tomography and optical coherence tomography angiography. The main outcome measures were as follows: 1) "normalized" reflectivity of en face image segmented at the ellipsoid zone level, which was calculated to quantify the photoreceptor damage, and 2) CC perfusion density. Secondary outcome measures were as follows: 1) superficial retinal capillary plexus (SCP), intermediate retinal capillary plexus (ICP), and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 2) SCP, ICP, and DCP vessel length density (based on a map with vessels of 1-pixel width); and 3) SCP, ICP, and DCP vessel diameter.

RESULTS

Mean ± SD age was 58.9 ± 11.1 years (range 38-79 years) in the NPDR group and 61.7 ± 11.3 years (range 39-87 years) in the control group (P > 0.05 for all the comparisons). Compared with controls, NPDR eyes displayed a lower "normalized" reflectivity (0.96 ± 0.25 in controls and 0.73 ± 0.19 in the NPDR group, P < 0.0001). Moreover, the NPDR group was characterized by an impaired perfusion in both the retinal and choroidal vasculature. In multiple regression analysis, ellipsoid zone "normalized" reflectivity displayed a significant direct association with CC perfusion density in patients with NPDR (P = 0.025 and P = 0.476, in NPDR and controls, respectively).

CONCLUSION

Eyes with NPDR are affected by macular hypoperfusion and photoreceptor damage, the latter investigated as ellipsoid zone "normalized" reflectivity. The diabetic choroidopathy seems to be strongly associated with photoreceptor damage.

Photoreceptor alteration in intermediate age-related macular degeneration

The aim of this study was to analyze photoreceptor alterations occurring in eyes with intermediate age-related macular degeneration (AMD) and to investigate their associations with choriocapillaris (CC) flow. In this retrospective case-control study, we collected data from 35 eyes with intermediate AMD from 35 patients who had swept source optical coherence tomography structural and angiography imaging obtained. A control group of 35 eyes from 35 healthy subjects was included for comparison. Our main outcome measure for comparison between groups was the normalized reflectivity of en face image segmented at the ellipsoid zone (EZ) level, which was calculated to quantify the photoreceptor damage. OCTA metrics to quantify CC flow signal were also computed. These metrics were measured in a circle centered on the fovea and with a diameter of 5 mm. In intermediate AMD eyes, the macular area occupied by drusen was identified. Therefore, the EZ reflectivity and CC flow signal were separately measured in regions without drusen ("drusen-free" region). Measurements were generated using previously published algorithms. Mean ± SD age was 74.1 ± 6.8 years in the intermediate AMD group and 72.1 ± 6.0 years in the control group (p = 0.206). The normalized EZ reflectivity was 0.76 ± 0.10 in the intermediate AMD group and 0.85 ± 0.08 in the control group (p < .0001). In the "drusen-free" region, the normalized EZ reflectivity was 0.77 ± 0.10 (p < .0001  vs. healthy controls) and was positively correlated with the CC flow signal density (ρ = - 0.340 and p = 0.020). In conclusion, eyes with intermediate AMD exhibit a diffuse reduced EZ normalized reflectivity, and this reduction is correlated with CC flow signal in the regions without drusen. This study supports the concept of the damage of the unit comprised of photoreceptor, CC, and intervening tissues as an early event in AMD.

Relationship Between Dry Retinal Volume and Visual Acuity in Diabetic Macular Edema

BACKGROUND AND OBJECTIVE

To evaluate the relationship between a novel spectral-domain optical coherence tomography (SD-OCT) parameter, predicted dry retinal volume (DRV), and visual acuity (VA) in subjects with diabetic macular edema.

PATIENTS AND METHODS

Twenty-eight eyes of 26 subjects with macular edema secondary to diabetic retinopathy (cases) and 10 healthy eyes of normal volunteers (controls) were included. Spectral-domain optical coherence tomography volume scans (512 × 128) were obtained before and 6 months to 12 months after anti-vascular endothelial growth factor therapy. The borders of the neurosensory retina, nerve fiber layer (NFL), and vitreous were manually defined using previously described grading software. NFL reflectivity was used to normalize the signal between eyes, allowing a normalized total retinal intensity to be computed for each eye by summing the brightness of every pixel in the retina on all B-scans. Using this normalized retinal intensity, a ratio of retinal intensity of cases over retinal intensity of normal was generated. The predicted DRV was computed by multiplying this calculated ratio with total retinal volume at baseline for each eye. Correlation analysis was performed between DRV at baseline and VA at baseline and final follow-up.

RESULTS

The mean ± standard deviation age of the cohort was 69 years ± 9.8 years, and 28% were female. Mean best-corrected VA (logMAR) improved from 0.56 ± 0.36 at baseline to 0.44 ± 0.32 at follow-up (P = .001). The uncorrected ("wet") total retinal volume of 13.25 mm³ ± 2.73 mm³ at baseline declined significantly to a posttreatment retinal volume of 10.92 mm³ ± 1.42 mm³. The predicted DRV (10.79 mm³ ± 1.42 mm³) was statistically similar to the post-treatment, actual retinal volume. No significant correlation was observed between DRV and post-treatment VA.

CONCLUSIONS

The predicted DRV at baseline showed good agreement with the actual observed posttreatment retinal volume. Thus, DRV may be a potentially useful parameter to estimate the extent of retinal tissue loss that may be obscured by the presence of concomitant edema. The lack of correlation between DRV and VA, however, suggests that other parameters, such as the integrity of the outer retinal bands, are likely important for visual outcome prediction. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:510-515.].

Relationship between Optical Intensity on Optical Coherence Tomography and Retinal Ischemia in Branch Retinal Vein Occlusion

Branch retinal vein occlusion (BRVO) may be complicated with retinal ischemia in some cases. The purpose of the current study is to investigate the relationship between optical intensity on optical coherence tomography (OCT) and retinal ischemia in BRVO. Twenty-seven eyes diagnosed with BRVO without macular edema were classified into two groups based on the presence or absence of retinal ischemia. The optical intensity of inner retinal layers and photoreceptor inner segment ellipsoid zone/retinal pigment epithelium layer (ISe/RPE) in the affected and unaffected regions were measured on OCT. Their ratio (Optical intensity ratio, OIR) was calculated and compared between affected and unaffected region. In the retinal ischemia group, the optical intensity of inner retinal layers was higher in the affected region compared to the unaffected region while the optical intensity of ISe/RPE was low. The OIR was significantly higher in the affected region compared to control (0.83 ± 0.17 vs 0.68 ± 0.09, p < 0.001). However, in the non-ischemic group, there was no significant difference between the affected and unaffected region. The BCVA was moderately correlated with OIR of affected region (r = 0.489, p = 0.010). Our study suggests that optical intensity ratio on OCT is correlated with retinal ischemia in BRVO.

ASSOCIATION OF DRUSEN VOLUME WITH CHOROIDAL PARAMETERS IN NONNEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

The choroid is thought to be relevant to the pathogenesis of nonneovascular age-related macular degeneration, but its role has not yet been fully defined. In this study, we evaluate the relationship between the extent of macular drusen and specific choroidal parameters, including thickness and intensity.

METHODS

Spectral domain optical coherence tomography images were collected from two distinct, independent cohorts with nonneovascular age-related macular degeneration: Amish (53 eyes of 34 subjects) and non-Amish (40 eyes from 26 subjects). All spectral domain optical coherence tomography scans were obtained using the Cirrus HD-OCT with a 512 × 128 macular cube (6 × 6 mm) protocol. The Cirrus advanced retinal pigment epithelium analysis tool was used to automatically compute drusen volume within 3 mm (DV3) and 5 mm (DV5) circles centered on the fovea. The inner and outer borders of the choroid were manually segmented, and the mean choroidal thickness and choroidal intensity (i.e., brightness) were calculated. The choroidal intensity was normalized against the vitreous and nerve fiber layer reflectivity. The correlation between DV and these choroidal parameters was assessed using Pearson and linear regression analysis.

RESULTS

A significant positive correlation was observed between normalized choroidal intensity and DV5 in the Amish (r = 0.42, P = 0.002) and non-Amish (r = 0.33, P = 0.03) cohorts. Also, DV3 showed a significant positive correlation with normalized choroidal intensity in both the groups (Amish: r = 0.30, P = 0.02; non-Amish: r = 0.32, P = 0.04). Choroidal thickness was negatively correlated with normalized choroidal intensity in both Amish (r = -0.71, P = 0.001) and non-Amish (r = -0.43, P = 0.01) groups. Normalized choroidal intensity was the most significant constant predictor of DV in both the Amish and non-Amish groups.

CONCLUSION

Choroidal intensity, but not choroidal thickness, seems to be associated with drusen volume in Amish and non-Amish populations. These observations suggest that choroidal parameters beyond thickness warrant further study in the setting of age-related macular degeneration.

Choroidal thickness in non-ocular Behçet's disease - A spectral-domain OCT study

Purpose

To evaluate choroidal thickness in patients with non-ocular Behçet's disease (BD) using spectral domain optical coherence tomography (SD-OCT) and to compare the results to normal eyes.

Methods

In this retrospective observational comparative study, we collected OCT and clinical data from the charts of 4 patients (7 eyes) with BD who had been referred for a screening eye exam and had a normal ocular examination. Data from 9 healthy volunteers (17 eyes) were collected as age-matched controls. The choroid was manually segmented from volume OCT scans using custom Doheny Image Reading Center OCT grading software (3D-OCTOR). Main outcome measures were choroidal thickness and intensity were compared between eyes of patients with BD and those of healthy controls.

Results

Eyes of patients with non-ocular BD had significantly thinner mean central subfield choroidal thickness (227.5 ± 56.93 versus 306.85 ± 17.85, P = 0.04) and central subfield choroidal volume (0.18 ± 0.04 vs 0.24 ± 0.02, P = 0.005). There was no significant difference in mean choroidal thickness in the whole ETDRS grid or in mean choroidal intensity in the central subfield and the whole ETDRS grid between eyes of patients with non-ocular BD and those of controls.

Conclusion

This study demonstrates that BD may have subclinical manifestations in the choroid, resulting in thinning of the choroid relative to normal eyes, even without overt signs of ocular involvement.

Postreceptor Neuronal Loss in Intermediate Age-related Macular Degeneration

PURPOSE

To investigate the relationship between ganglion cell complex (GCC) thickness and photoreceptor alterations in eyes with intermediate age-related macular degeneration (AMD).

DESIGN

Retrospective case-control study.

METHODS

We collected data from 68 eyes with intermediate AMD from 68 patients with spectral-domain optical coherence tomography (SDOCT) imaging. A control group of 50 eyes from 50 healthy subjects was included for comparison. Our main outcome measures for comparison between groups were (1) the average and minimum GCC thickness and (2) the "normalized" reflectivity of the ellipsoid zone (EZ) en face image.

RESULTS

The average and minimum GCC thicknesses were thinner in AMD patients (69.54 ± 9.30 μm and 63.22 ± 14.11 μm, respectively) than in healthy controls (78.57 ± 6.28 μm and 76.28 ± 6.85 μm, P < .0001 and P < .0001, respectively). Agreement was found to be excellent in the "normalized" EZ reflectivity assessment (intraclass correlation coefficient = 0.986, coefficient of variation = 1.11). The EZ "normalized" reflectivity was 0.67 ± 0.11 in controls and 0.61 ± 0.09 in the AMD group (P = .006). In univariate analysis, EZ "normalized" reflectivity was found to have a significant direct relationship with average (P < .0001) and minimum (P < .0001) GCC thickness in AMD patients, but not in controls (P = .852 and P = .892, respectively).

CONCLUSIONS

Eyes with intermediate AMD exhibit GCC thinning, as well as a reduced EZ "normalized" reflectivity, and these parameters are correlated. This study supports the concept of postreceptor retinal neuronal loss as a contributor to retinal thinning in intermediate AMD.

Correlation between retinal sensitivity and cystoid space characteristics in diabetic macular edema

PURPOSE

To evaluate the correlation between retinal sensitivity and cystoid space characteristics in eyes with diabetic macular edema (DME).

MATERIALS AND METHODS

Prospective cross-sectional study of 22 subjects with DME (32 treatment-naïve eyes). All study subjects underwent complete ophthalmic examination, including slit-lamp biomicroscopy and dilated fundus examination. All subjects underwent spectral domain optical coherence tomography (SD-OCT) and microperimetry (MP). Intraretinal cystoid space (ICS) volume was generated after manual delineation of cystoid space boundaries using the three-dimensional-OCT software. Various SD-OCT parameters, including retinal thickness, retinal volume, cystoid space volume, cystoid space intensity, and outer retinal structure integrity, were correlated with MP parameters and best-corrected visual acuity (BCVA).

RESULTS

Subject's mean age was 57 ± 9 years. The mean logarithm of minimum angle of resolution BCVA was 0.4 ± 0.2. The intraclass correlation coefficient for inter- and intra-grader assessment of cystoid space volume by manual delineation was 0.99 and 0.99, respectively. Mean total ICS volume was 0.4 ± 0.4 mm 3 and for the foveal center, subfield was 0.1 ± 0.1 mm 3 . Mean retinal sensitivity was 12.89 ± 10 dB; however, foveal retinal sensitivity was 12.3 ± 11.1 dB. We found no significant correlation between BCVA and total cystoid space volume (r = 0.33, P = 0.06). Correlation between total retinal sensitivity and total ICS was negative and nonsignificant (r = -0.17, P = 0.36). Correlation between foveal retinal sensitivity and foveal cystoid space intensity was moderate and marginally significant (r = -0.43, P = 0.05).

CONCLUSION

Total cystoid space volume was not significantly correlated with BCVA or total retinal sensitivity in subjects with DME. Foveal cystoid space optical intensity was negatively correlated with foveal retinal sensitivity. These findings suggest further investigation of cystoid space characteristics in the setting of DME may be of value.

Choroidal Imaging with Swept-Source Optical Coherence Tomography in Patients with Birdshot Chorioretinopathy: Choroidal Reflectivity and Thickness

PURPOSE

To characterize choroidal thickness and choroidal reflectivity in the eyes of patients with birdshot chorioretinopathy (BSCR).

DESIGN

Cross-sectional observational study.

PARTICIPANTS

Two hundred twenty BSCR patients and 59 healthy controls.

METHODS

Patients with BSCR and healthy controls underwent imaging of the macula in both eyes with a swept-source optical coherence tomography device (DRI-OCT1 Atlantis; Topcon). Images were exported from the device, and analysis was performed by 2 graders in the Doheny Image Reading Center using Image J software. The choroidal thickness at the foveal center was measured. In addition, the inner and outer boundaries of the choroid and retinal pigment epithelium (RPE) as well as the inner retinal surface all were segmented to allow the brightness and reflectivity of the pixels in the choroid, RPE band, and overlying vitreous to be quantified. An adjusted or normalized choroidal reflectivity, with the RPE as the bright reference standard and the vitreous as the dark reference standard, was computed using the formula: normalized choroidal reflectivity = (choroidal reflectivity-vitreous reflectivity)/RPE reflectivity.

MAIN OUTCOME MEASURES

Choroidal reflectivity and choroidal thickness.

RESULTS

Three hundred eighty-six eyes in the BSCR group and 59 eyes in the control group were included in this analysis. Higher choroidal reflectivity and lower choroidal thickness were documented in inactive BSCR patients compared with active BSCR and controls (P < 0.01). Active BSCR patients showed lower choroidal thickness compared with controls (P < 0.01). There was a negative correlation between choroidal reflectivity and choroidal thickness (r = -0.793; P < 0.001). On multiple regression analysis, choroidal thickness, age, and disease duration (all P < 0.01) all were significant predictors of choroidal reflectivity.

CONCLUSIONS

Choroidal reflectivity and choroidal thickness changes are evident in active and inactive BSCR patients. Novel choroidal parameters such as choroidal reflectivity may warrant further study in the setting of BSCR.

Residual and Dynamic Range of Retinal Nerve Fiber Layer Thickness in Glaucoma: Comparison of Three OCT Platforms

PURPOSE

To estimate visual field (VF) sensitivity at which retinal nerve fiber layer (RNFL) thinning reaches the measurement floor and at which RNFL stops thinning (change points), the dynamic range of RNFL thickness, and the number of steps from normal to RNFL floor among three optical coherence tomography (OCT) devices.

METHODS

Glaucomatous patients (n = 58) and healthy subjects (n = 55-60) prospectively underwent VF testing and RNFL thickness measurement with Cirrus, Spectralis, and RTVue. Change points and corresponding RNFL thicknesses were estimated with simple linear regression (SLR) and Bayesian change point (BCP) analyses. The dynamic range and number of steps to RNFL floor were determined.

RESULTS

The average VF change points and corresponding residual thickness at the time RNFL stopped thinning were -22.2 dB and 57.0 μm (Cirrus), -25.3 dB and 49.2 μm (Spectralis), and -24.6 dB and 64.7 μm (RTVue). The RNFL dynamic ranges derived from SLR values were wider on Spectralis (52.6 μm) than on Cirrus (35.4 μm) and RTVue (35.5 μm); the corresponding number of steps to reach the RNFL floor were 9.0 on Cirrus, 10.6 on Spectralis, and 8.3 on RTVue.

CONCLUSIONS

The relative VF sensitivity at which average RNFL thickness reaches the measurement floor, the residual layer thickness, and RNFL dynamic measurement range differ among the three devices. However, the number of steps from normal to the RNFL thickness floor is comparable.

Relationship Between Subretinal Hyperreflective Material Reflectivity and Volume in Patients With Neovascular Age-Related Macular Degeneration Following Anti-Vascular Endothelial Growth Factor Treatment

BACKGROUND AND OBJECTIVE

To assess the relationship between subretinal hyperreflective material (SRHM) reflectivity and volume in patients treated with anti-vascular endothelial growth factor (VEGF) therapy for choroidal neovascularization secondary to exudative age-related macular degeneration (AMD).

PATIENTS AND METHODS

Data from 17 eyes of 16 patients with neovascular AMD undergoing anti-VEGF therapy were collected retrospectively. Optical coherence tomography (OCT) data were obtained using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) 512 × 128 macular cube protocol. Detailed manual segmentation was performed for each case using customized grading software.

RESULTS

The mean macular volume declined from 10.4 mm(3) at baseline to 9.6 mm(3) at 12 months. SRHM volume declined from 0.33 mm(3) to 0.12 mm(3), whereas reflectivity increased from 0.48 to 0.64 units (P = .012). SRHM reflectivity correlated positively with logarithm of the minimum angle of resolution (logMAR) acuity (r = .49, P = .04) but correlated with SRHM volume (r = -0.50, P = .04) only at baseline.

CONCLUSION

SRHM reflectivity, which correlated partially with SRHM volume, appears to carry independent information regarding disease activity. SRHM reflectivity may be useful for monitoring disease activity and response to therapy.