Comparing Gonioscopy With Visante and Cirrus Optical Coherence Tomography for Anterior Chamber Angle Assessment in Glaucoma Patients.

Influence of Cataract Surgery on Optical Coherence Tomography and Neurophysiology Measurements in Patients With Retinitis Pigmentosa

To determine whether optical coherence tomography (OCT) device-type influences clinical grading of OCT imaging in the context of exudative age-related macular degeneration (AMD). Ninety-six paired OCT scans from 49 patients with active exudative AMD were obtained on both the time-domain Stratus OCT system and the spectral-domain Cirrus OCT system at the same visit. Three independent graders judged each scan for the presence of intraretinal fluid (IRF) or subretinal fluid (SRF). The degree of grader consensus was evaluated and the ability of the systems to detect the presence of disease activity was analysed. Cirrus OCT generated a higher degree of inter-grader consensus than Stratus OCT with higher intraclass correlation coefficients for all parameters analysed. A pair-wise comparison of Cirrus OCT with Stratus OCT systems revealed that Cirrus-based gradings more frequently reported the presence of SRF and IRF and detected overall neovascular activity at a higher rate (P<0.05) compared with Stratus-based gradings. The choice of time-domain (Stratus) vs spectra-domain (Cirrus) OCT systems has a measurable impact on clinical decision making in exudative AMD. Spectral-domain OCT systems may be able to generate more consensus in clinical interpretation and, in particular cases, detect disease activity not detected by time-domain systems. Clinical trials using OCT-based clinical evaluations of exudative AMD may need to account for these inter-system differences in planning and analysis.

To determine the effect of head tilt and ocular compensatory mechanisms on retinal nerve fiber layer (RNFL) thickness measurements using the Cirrus and Spectralis spectral-domain optical coherence tomography (OCT) in healthy eyes. Our secondary objective was to assess the visual influence on ocular compensatory mechanisms during head tilt. This is a prospective, observational study. A single randomly selected eye was scanned undilated in 3 positions (baseline, right, and left tilt) using both machines. In addition, patching was also done for the contralateral eye during head tilt and RNFL measurements repeated. The paired t test was used to analyze effect on RNFL thickness. One-way repeated-measures analysis of variance was used to compare differences in RNFL measurements. In Cirrus OCT RNFL analysis, ipsilateral head tilt resulted in superior thinning and temporal thickening, whereas contralateral head tilt resulted in inferior thinning, nasal thickening, as well as temporal thickening (all P<0.05). Head tilt did not cause any significant change in RNFL thickness with Spectralis OCT (P>0.05). Patching the contralateral eye also did not alter Cirrus RNFL measurement errors due to head tilt. Head tilt can affect the measurement of the RNFL thickness in Cirrus OCT, and ocular compensatory mechanisms were not sufficient to prevent this. In contrast, Spectralis OCT RNFL thickness measurements were not affected by head tilt. Patching the contralateral eye during head tilt in Cirrus OCT also did not affect RNFL variability. The visual influence on ocular compensatory mechanisms during head tilt appears insignificant.

Automatically generated measurements of the retinal volume or the central retinal thickness are based on correctly set threshold lines on the retinal surface and the retinal pigment epithelium. The purpose of this study was to compare the accuracy of threshold algorithm lines of Stratus optical coherence tomography (OCT) with those of Cirrus OCT. A consecutive series of patients at least 50 years of age with exudative age-related macular degeneration was included. Stratus OCT (retinal thickness program) and Cirrus OCT (macular cube 512 x 128) were performed by the same examiner, the sequence of the examinations was randomized. Two independent examiners evaluated the positioning of the threshold algorithm lines and performed a grading of the failures. Logistic regression analysis was applied for evaluation of the failure rate. One hundred four patients were included. For the entire OCT examination (6 scans Stratus OCT, 128 scans Cirrus OCT) algorithm line failures were detected in 69.2% of the Stratus OCT and in 25% of the Cirrus OCT examinations, with the difference reaching statistical significance (P < 0.001). The median failure grade was 1 (0-6) for Stratus and 0 (0-5.15) for Cirrus OCT. Age, measurement sequence, and investigator did not influence the error rates. With Cirrus OCT automatically performed and therefore objective measurements of central retinal thickness and retinal volume were provided correctly in 69.2% of the scans. Furthermore, this latest software version offers the possibility of manual correction of false positioned algorithm lines (ClinicalTrials.gov number, NCT00568191).

To investigate the effect of laser peripheral iridotomy (LPI) in subgroups of angle closure eyes based on anterior segment optical coherence tomography (AS OCT)-derived parameters. Angle closure (primary angle closure [PAC] or PAC glaucoma [PACG]) eyes were imaged using AS OCT before and 2 weeks after LPI. A hierarchical cluster analysis was performed using AS OCT parameters obtained before LPI, such as anterior chamber depth (ACD), anterior chamber width (ACW), iris cross-sectional area (IA), angle opening distance and iris thickness at 750 μm from the scleral spur (AOD750, IT750), iris curvature (IC), lens vault (LV), and anterior chamber area (ACA) to subclassify angle closure eyes. After LPI, parameters were compared to evaluate whether the outcome of LPI differed among the subgroups determined by cluster analysis. Cluster analysis generated two distinct clusters showing significantly different anatomical features. Cluster 1 (61 eyes) had lower ACD (P<0.001), higher LV (P=0.008), lower AOD750 (P<0.001), and lower ACW (P<0.001) than cluster 2 (27 eyes). The proportional change in AOD750 after LPI was significantly greater in cluster 1 than in cluster 2 (116.4±117.3% and 46.4±45.7%, respectively, P=0.007). The outcomes of LPI differed between angle closure subgroups with different anatomical characteristics. Our results provide evidence that angle closure patients can be grouped according to different anatomical anterior segment features and that the pathogenic mechanism of angle closure may differ among subgroups, suggesting that the treatment and follow-up plan should be customized according to subgroup features.

Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS. To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC). This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up. The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 μm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 μm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 μm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance. This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 μm and light-room ARA at 750 μm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.

To report a case of bilateral non-pupillary block angle closure glaucoma after Visian Implantable Collamer Lens (ICL, STAAR Surgical) surgery. A 35-year-old woman with high myopia, white-to-white measurements of 11.8 mm in the right eye and 11.9 mm in the left eye, and anterior chamber depths >3 mm in both eyes underwent simultaneous bilateral ICL implantation with 13.2-mm lenses. Persistent, bilateral acute angle closure developed despite multiple patent peripheral iridotomies and iridectomies. Visante anterior segment optical coherence tomography (AS-OCT, Carl Zeiss Meditec) revealed profound vaulting of the ICLs and angle closure. Both ICLs were explanted. After explantation, ultrasound biomicroscopy demonstrated a sulcus-to-sulcus diameter of 10.8 mm in the right eye and 11.2 mm in the left eye. The correlation between white-to-white and sulcus-to-sulcus measurements were poor in this patient, resulting in extreme vaulting of the ICL and angle closure from a non-pupillary block mechanism. Proper identification of the mechanism of angle closure is aided by AS-OCT. For non-pupillary block mechanisms, ICL extraction is necessary.

To evaluate the accuracy and reproducibility of retinal thickness measurements in healthy and epiretinal membranes (ERM) eyes by Cirrus and Spectralis Fourier-domain optical coherence tomography devices. Eighty-seven ERM and 122 healthy subjects underwent 3 macular scans using both optical coherence tomography instruments. Mean thickness measurements in the nine Early Treatment Diabetic Retinopathy Study areas were compared, evaluating the repeatability and the relationship between devices. Macular thickness increase was detected in ERM eyes for all optical coherence tomography parameters (P < 0.001). Mean foveal thickness was 423.5 ± 81.4 and 438.0 ± 54.2 μm for ERM eyes and 267.1 ± 20.2 and 277.5 ± 18.9 μm for healthy eyes using Cirrus and Spectralis, respectively. Macular average thickness in ERM eyes as determined by both optical coherence tomography was correlated (r = 0.812; P < 0.001) but significantly different (P = 0.044). In ERM eyes, measurements showed a mean of the coefficients of variation of 2.95%, 2.2%, and 1.01% using Cirrus, Spectralis, and Spectralis progression feature, respectively. Intraclass correlation coefficients were higher than 0.919 in all cases. Reproducibility of both Cirrus and Spectralis optical coherence tomography was high in healthy and ERM eyes. However, considerable differences were found between macular thickness measurements obtained by both devices despite the high correlation between them.

Anterior Segment Imaging Predicts Incident Gonioscopic Angle Closure

Application of Visante Optical Coherence Tomography Tear Meniscus Height Measurement in the Diagnosis of Dry Eye Disease

To evaluate and compare the glaucoma detection capabilities afforded by retinal nerve fiber layer (RNFL) thickness and deviation maps obtained using Cirrus spectral domain optical coherence tomography (Cirrus OCT), and GDx employing variable corneal compensation (GDx-VCC) in glaucoma patients with early, localized visual field (VF) loss. This prospective controlled, comparative study was performed on 42 eyes with localized VF defects, and 42 age/refractive error-matched healthy eyes. All participants were imaged by both imaging devices at the same visit. The area of the RNFL defect in each deviation map, corresponding to a VF defect, was analyzed by direct counting of color-coded superpixels in each device. Receiver operating characteristic (ROC) curves were constructed and compared between Cirrus OCT and GDx-VCC. The areas under the ROCs (AUCs) of RNFL quadrant thicknesses in hemifields with visual field (VF) defects did not differ significantly (Cirrus OCT; 0.961, GDx-VCC; 0.919, P = 0.07). However, Cirrus OCT afforded a better diagnostic ability, by deviation map analysis, than did GDx-VCC (0.972 vs 0.887, P = 0.02). The RNFL thicknesses assessed by either Cirrus OCT or GDx-VCC were comparable in terms of early glaucoma diagnostic capability. However, when areas containing RNFL defects were analyzed via deviation mapping, Cirrus OCT was better than GDx-VCC.

Oculodermal melanocytosis (ODM) is a rare condition with glaucoma being the most common complication in these eyes. Open angle glaucoma is the commonest variant and presence of angle closure in these eyes should raise a suspicion of ciliary body or uveal tumor, which needs to be evaluated before any surgical intervention is planned. We report a case of unilateral ODM with secondary angle closure glaucoma. Angle closure in an eye with ODM is extremely rare, ultrasound B-scan showed thickened choroid, and ultrasound biomicroscopy showed 360° ciliary body hypertrophy. Incisional biopsy &amp; fine needle aspiration cytology of the ciliary body tissue was performed, and histopathological features were suggestive of a benign hypertrophy ruling out ciliary body melanoma. Subsequently, a glaucoma drainage device surgery was performed in the right eye. To the best of our knowledge, benign ciliary body hypertrophy causing intractable angle closure glaucoma in a case of ODM has not been reported.

This study was conducted to analyze the profile and thickness of endothelial keratoplasty lenticules prepared from fresh donated whole eyes with Visante optical coherence tomography (V-OCT) compared to measurements obtained from ultrasound pachymetry (USP) at the Central Eye Bank of Iran. Microkeratome-assisted precut corneas were prepared for Descemet stripping automated endothelial keratoplasty by using standard eye bank protocol. Central posterior lenticule thickness (CPLT) on fresh whole eye, before excising corneoscleral disc and transferring to Optisol-GS, was measured by USP. V-OCT was used to measure central, paracentral, and midperipheral thicknesses of lenticules after transferring the tissue to Optisol-GS. Chi Square and Bonferroni tests were respectively used to uncover the differences between the USP and V-OCT measurements and also the thickness profile of lenticules. Postoperative reports for the entire transplanted lenticules were recorded. Accordingly, on evaluation of 312 enrolled precut corneas, CPLT measurements by V-OCT versus USP were statistically different (mean: 136µm vs 165µm, respectively; P=0.008). Thickness profile of the posterior lenticules revealed increased thickness from the central to the peripheral parts of the cornea (mean increase of 16µm at the pericentral and 64.2µm at the peripheral locations, respectively); however, the increase in the thickness was relatively symmetrical. Postoperative reports of transplanted lenticules were unremarkable, since there were no posterior flap detachments. In essence, V-OCT measurements of microkeratome-assisted precut lenticules prepared from fresh donated whole eyes averaged 29μm thinner than USP measurements and revealed a significant but symmetric increase of thickness towards the peripheral parts of the corneas. However, the variation in the thickness profile did not affect the attachment or the clarity of transplanted precut lenticlues.

This study aimed to evaluate the relationship between glaucoma progression and estimates of the retinal ganglion cells (RGCs) obtained by combining structural and functional measurements in patients with glaucoma.In the present observational cohort study, we examined 116 eyes of 62 glaucoma patients. Using Cirrus optical coherence tomography (OCT), a minimum of 5 serial retinal nerve fiber layer (RNFL) measurements were performed in all eyes. There was a 3-year separation between the first and last measurements. Visual field (VF) testing was performed on the same day as the RNFL imaging using the Swedish Interactive Threshold Algorithm Standard 30–2 program of the Humphrey Field Analyzer. Estimates of the RGC counts were obtained from standard automated perimetry (SAP) and OCT, with a weighted average then used to determine a final estimate of the number of RGCs for each eye. Linear regression was used to calculate the rate of the RGC loss, and trend analysis was used to evaluate both serial RNFL thicknesses and VF progression.Use of the average RNFL thickness parameter of OCT led to detection of progression in 14 of 116 eyes examined, whereas the mean deviation slope detected progression in 31 eyes. When the rates of RGC loss were used, progression was detected in 41 of the 116 eyes, with a mean rate of RGC loss of −28,260 ± 8110 cells/year.Estimation of the rate of RGC loss by combining structural and functional measurements resulted in better detection of glaucoma progression compared to either OCT or SAP.

To assess and compare the anterior chamber angle (ACA) by different anterior segment imaging techniques. Forty healthy eyes of 40 normal subjects were recruited and 3 consecutive measurements of ACA were determined prospectively utilizing Visante optical coherence tomography (OCT), slit-lamp OCT (SL-OCT), and Pentacam. Statistical significance of interdevice differences between measurements was evaluated by Wilcoxon signed rank test and Bland-Altman analysis. The repeatability of 3 consecutive measurements was analyzed by repeated measured analysis of variance. Mean nasal and temporal ACA were detected as 31.2+/-8.7 and 32.1+/-8.5 degrees by Visante OCT; 41.6+/-5.9 and 41.8+/-5.2 degrees by Pentacam; and 42.9+/-10.0 and 43.3+/-10.1 degrees by SL-OCT. All devices displayed a high intrasession repeatability (Scheffe multiple comparison, p>0.05). ACA detected by Visante OCT were found significantly different from ACA calculated by Pentacam and SL-OCT (p<0.05). On the other hand, ACA data obtained by Pentacam and SL-OCT were found to be statistically similar (p>0.05). Although noncontact ACA measurements using all modalities were easy to handle and demonstrated good repeatability in healthy participants, the tested devices were not regarded as comparable. Hence, the clinician should take the different modalities into consideration during ACA assessment using various devices.