Anterior Segment Optical Coherence Tomography Images Research Articles

Longitudinal Evaluation of Wound Healing after Penetrating Corneal Injury: Anterior Segment Optical Coherence Tomography Study

ABSTRACTPurpose: Ocular imaging can enhance our understanding of wound healing. We report anterior segment optical coherence tomography (ASOCT) findings in penetrating corneal injury.Methods: Serial ASOCT was performed after repair of penetrating corneal injury. Internal aberrations of wound edges were labeled as “steps” or “gaps” on ASOCT images. The wound type was characterized as: type 1: continuous inner wound edge or step height ≤ 80 µm; type 2: step height > 80 µm; type 3: gap between wound edges; and type 4: intraocular tissue adherent to wound. Surgical outcomes of different wound types were compared.Results: 50 consecutive patients were included (6 females, 44 males; mean age 33 ± 12 years). The average size of wound was 4.2 ± 2.6 mm (type 1, 8 eyes; type 2, 27 eyes; type 3, 12 eyes; type 4, 3 eyes). At the end of 3 months, 70% (n = 35) of the wounds were type 1. At the end of 6 months, all type 1 wounds had healed completely, whereas about half of type 2 (48.1%) and type 3 (50%) wounds had recovered to type 1 configuration. The wound type at baseline affected the height of step (p = 0.047) and corneal thickness at 6 months (p = 0.035).Conclusions: ASOCT is a useful tool for monitoring wound healing in cases with penetrating corneal injury. Majority of the wound edges appose between 3 and 6 months after trauma. In our study, baseline wound configuration affected the healing pattern.

Benefit of Measuring Anterior Segment Structures Using an Increased Number of Optical Coherence Tomography Images: The Chinese American Eye Study.

PurposeThe purpose of this study was to evaluate the benefit of analyzing an increased number of anterior segment optical coherence tomography (AS-OCT) images on measurement values of various anterior segment parameters.MethodsSubjects for this cross-sectional study were recruited from the Chinese American Eye Study (CHES), a population-based study in Los Angeles, CA. Thirty-two AS-OCT images were acquired from one eye each of 83 consecutive subjects. Sixteen parameters were analyzed in each image, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), scleral spur angle (SSAngle), lens vault (LV), pupillary diameter (PD), anterior chamber depth (ACD), anterior chamber width (ACW), iris area (IA), and anterior chamber area (ACA). Data from 1, 2, 4, 8, 16, or 32 OCT images were averaged across subjects to calculate the range and mean of measurement values for each parameter.ResultsAnatomical variations were poorly captured with fewer OCT images for AOD, ARA, TISA, SSAngle, IA, and LV. For these parameters, the range and mean of measurement values obtained from one OCT image deviated from 32-image values by up to 43.9% and 13.3% of the 32-image mean, respectively. These deviations decreased when additional OCT images were analyzed. Deviations from 32-image range and mean values were less pronounced regardless of image number for PD, ACD, ACW, and ACA, measuring up to 3.5% and 5.0%, respectively.ConclusionsA multi-image approach should be the standard in OCT-based studies of AOD, ARA, TISA, TIA, SSAngle, IA, and LV.

Changes in Anterior Segment Morphology and Predictors of Angle Widening after Laser Iridotomy in South Indian Eyes

To compare anterior segment optical coherence tomography (ASOCT) angle morphology before and after laser peripheral iridotomy (LPI) in a cohort of South Indian subjects with primary angle-closure suspect (PACS) or primary angle-closure/primary angle-closure glaucoma (PAC/PACG) and to examine baseline parametersassociated with angle widening. Prospective observational study. A total of 244 subjects aged ≥30 years with PACS or PAC/PACG in at least 1 eye. The ASOCT images and angle gonioscopic grades were analyzed for all subjects at baseline and 2 weeks after LPI. Multivariable linear and logistic regression models were used to determine predictors of angle widening (change in mean angle opening distance [AOD750]) and angle opening (all 4 quadrants with trabecular meshwork [TM] visible on gonioscopy after LPI). Change in ASOCT parameters with LPI and baseline predictors of angle widening. Laser peripheral iridotomy resulted in angle widening on ASOCT with significant increases in AOD750, angle recess area, and trabecular iris surface area (P < 0.05 for all). Gonioscopically, 44.7% of all subjects had open angles in all 4 quadrants after LPI, with a greater percentage of angles open in the PACS group compared with the PAC/PACG group (52.4% vs. 36.4%; P= 0.01). In multivariable regression analyses, greater postoperative angle widening as defined by change in AOD750 was associated with shorter baseline AOD750 and axial length, and greater baseline anterior chamber depth, iris curvature, and lens vault (P≤0.002 for all). Gonioscopic angle opening after LPI was more common with wider baseline angle width (modified Shaffer grade) and lower cup-to-disc ratio (P < 0.001 for both). In a South Indian population with PACS or PAC/PACG, LPI results in significant anterior chamber angle widening seen on both ASOCT and gonioscopy, although some degree of persistent iridotrabecular contact was present in approximately half of PACS eyes and approximately two thirds of PAC/PACG eyes on gonioscopy. The greatest widening by ASOCT was observed in eyes with features most consistent with greater baseline pupillary block.

DYNAMIC CHANGES OF THE ANTERIOR CHAMBER ANGLE PRODUCED BY INTRAVITREAL ANTI-VASCULAR GROWTH FACTOR INJECTIONS.

To use anterior segment optical coherence tomography (AS-OCT) to evaluate the anterior chamber after intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections. Preinjection and immediate postinjection AS-OCT images were taken and measurements were compared including angle opening distance (AOD) and trabeculo-iris space area (TISA) at 500 μm and 750 μm from the scleral spur (AOD500, AOD750, TISA500 and TISA750, respectively), and the scleral spur angle. Twenty-one eyes from 21 patients were studied. There was significant narrowing of the temporal AOD500, AOD750, and temporal angle after injection (P = 0.03, 0.01, and 0.02, respectively). The percentage of narrowing of the nasal TISA500 and TISA750 was significantly greater in phakic versus pseudophakic eyes (P = 0.03 and 0.02, respectively). A higher postinjection IOP was correlated with increased narrowing of the nasal AOD500, TISA500, TISA750, and nasal angle (R = 0.22, 0.28, 0.34 and 0.20; P = 0.03, 0.01, 0.005 and 0.04, respectively) and a smaller preinjection anterior chamber depth in phakic eyes (R = 0.53, P = 0.01). After an anti-vascular endothelial growth factor injection, there is significant narrowing of the temporal anterior chamber angle in all eyes and increased narrowing of the nasal angle in phakic compared with pseudophakic eyes. Physicians performing intravitreal injections should be aware of these associations as they may contribute to our understanding of prolonged elevation of IOP after injections.

Change of Optical Intensity during Healing Process of Corneal Wound on Anterior Segment Optical Coherence Tomography.

The purpose of this study is to investigate the process of corneal wound healing after penetrating injury with the change in optical intensity on anterior segment optical coherence tomography (AS-OCT) and to investigate factors associated with severity of corneal scar. Forty-seven eyes from 47 patients with repaired corneal laceration were included. AS-OCT was performed on 1day, 1week, 1, 3 and 6 months after primary repair. Internal aberrations of wound edges were observed on AS-OCT images. Parameters including height of steps, width of gaps, maximal corneal thickness, area and optical intensity of corneal wound/scar were measured. The relationship between the parameters at day 1 and the optical intensity at 6 months were analyzed. The results showed that optical intensity of corneal wound/scar increased from 124.1 ± 18.8 on day 1 postoperatively to 129.3 ± 18.7, 134.2 ± 23.4, 139.7 ± 26.5, 148.2 ± 26.4 at 1 week, 1 month, 3 months and 6 months postoperatively. Height of steps at 1 day after surgery was the only factor identified as correlated with optical intensity of corneal scar at 6 months (beta = 0.34, p = 0.024). The increase of optical intensity represents the process of fibrosis of corneal wound healing. Higher step after suturing is associated with more severity of corneal scar at last.

Automatic anterior chamber angle structure segmentation in AS-OCT image based on label transfer.

The anterior chamber angle (ACA) plays an important role for diagnosis and treatment of angle-closure glaucoma. Anterior Segment Optical Coherence Tomography (AS-OCT) imaging is qualitative and quantitative assessment for the ACA structure. In this paper, we propose a novel fully automatic segmentation method for anterior chamber angle structure in AS-OCT. In our method, the initial labels are obtained by using label transfer from the AS-OCT reference dataset. Then, these labels are refined and utilized as the landmarks to support the structure segmentation. Finally, the major clinical structures: corneal boundary, iris region, and trabecular-iris contact, are extracted as the segmentation result. Experiments show that our proposed method achieve the satisfactory segmentation performance on the clinical AS-OCT dataset. Our proposed method has potential in the applications of clinical ACA parameter measurement and automatic glaucoma classification.

Qualitative evaluation of anterior segment in angle closure disease using anterior segment optical coherence tomography

PurposeTo evaluate different mechanisms of primary angle closure (PAC) and to quantify anterior chamber (AC) parameters in different subtypes of angle closure disease using anterior segment optical coherence tomography (AS-OCT). MethodsIn this prospective study, 115 eyes of 115 patients with angle closure disease were included and categorized into three groups: 1) fellow eyes of acute angle closure (AAC; 40 eyes); 2) primary angle closure glaucoma (PACG; 39 eyes); and 3) primary angle closure suspect (PACS; 36 eyes). Complete ophthalmic examination including gonioscopy, A-scan biometry, and AS-OCT were performed. Based on the AS-OCT images, 4 mechanisms of PAC including pupillary block, plateau iris configuration, thick peripheral iris roll (PIR), and exaggerated lens vault were evaluated. Angle, AC, and lens parameter variables were also evaluated among the three subtypes. ResultsThere was a statistically significant difference in the mechanism of angle closure among the three groups (p = 0.03). While the majority of fellow eyes of AAC and of PACS eyes had pupillary block mechanism (77.5% and 75%, respectively), only 48.7% of PACG eyes had dominant pupillary block mechanism (p = 0.03). The percentage of exaggerated lens vault and plateau iris mechanisms was higher in PACG eyes (25.5% and 15.4%, respectively). Fellow eyes of AAC had the shallowest AC (p = 0.01), greater iris curvature (p = 0.01), and lens vault (p = 0.02) than PACS and PACG eyes. Iris thickness was not significantly different among the three groups (p = 0.45). ConclusionUsing AS-OCT, we found that there was a statistically significant difference in the underlying PAC mechanisms and quantitative AC parameters among the three subtypes of angle closure disease.

Prospective observational study of conjunctival scarring after phacoemulsification.

To examine whether anterior segment-optical coherence tomography (AS-OCT) can detect conjunctival scarring after transscleral phacoemulsification and whether temporal transscleral phacoemulsification causes scarring in the superior conjunctiva. Transscleral phacoemulsification was performed in the superior conjunctiva (superior incision group) or the temporal conjunctiva (temporal incision group). Anterior segment-optical coherence tomography (AS-OCT) images of the superior conjunctiva were obtained before and after surgery. We quantified the thickness of the conjunctiva and preservation rates of the borderlines among thesubconjunctival layers. The relationship between the AS-OCT images and histology was evaluated in rabbit eyes with phacoemulsification. Each group comprised 25 patients. At ≤1month after surgery, the superior conjunctiva was significantly thicker in the superior incision group than the temporal incision group (1day, 7days, and 1month after surgery; p<0.0001, p<0.0001, and p<0.001 respectively); however, there were no significant differences between the two groups at ≥2months. The borderline of the conjunctival stroma/Tenon's capsule and the borderline of the Tenon's capsule/sclera were preserved significantly better in the temporal incision group after surgery (p<0.0001). The cell densities in the conjunctiva of the rabbit temporal incision group were unchanged after surgery, whereas the rabbit superior incision group had significantly more neutrophils (p=0.0001) and myofibroblasts (p<0.0001) in the superior conjunctiva than the temporal incision group. Anterior segment-optical coherence tomography (AS-OCT) images can detect conjunctival scarring after transscleral phacoemulsification. The layer structures in the superior conjunctiva are unaffected by temporal transscleral incision.

ULTRASOUND BIOMICROSCOPY AND ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY IN THE DIAGNOSIS AND MANAGEMENT OF GLAUCOMA

We aimed to summarize the applications, strengths and weaknesses of two anterior segment imaging modalities: the ultrasound biomicroscopy (UBM) and the anterior segment optical coherence tomography (AS-OCT) in the diagnosis and surgical management of glaucoma. This narrative review was based on our clinical experience with these technologies supported on scientific literature review through Medline via PubMed ® . The syntax used in the search was “Glaucoma AND Anterior Chamber Angle AND Ultrasound Biomicroscopy OR UBM AND Anterior Segment Optical Coherence Tomography OR AS-OCT”. Publications were selected based on relevance, redundancy, and authorship. Additionally UBM and AS-OCT images were selected from the two of the authors’ personal archives to illustrate prevalent glaucoma findings and post-operatory using both technologies. AS-OCT and UBM share overlapping characteristics and are both useful in glaucoma diagnosis and post-operative assessment. However, particular technical features of each will direct the best application to clarify specific glaucoma etiologies, to guide in the most effective management and to explain glaucoma surgical outcomes.

Automated anterior segment OCT image analysis for Angle Closure Glaucoma mechanisms classification

Background and objectivesAngle closure glaucoma (ACG) is an eye disease prevalent throughout the world. ACG is caused by four major mechanisms: exaggerated lens vault, pupil block, thick peripheral iris roll, and plateau iris. Identifying the specific mechanism in a given patient is important because each mechanism requires a specific medication and treatment regimen. Traditional methods of classifying these four mechanisms are based on clinically important parameters measured from anterior segment optical coherence tomography (AS-OCT) images, which rely on accurate segmentation of the AS-OCT image and identification of the scleral spur in the segmented AS-OCT images by clinicians. MethodsIn this work, a fully automated method of classifying different ACG mechanisms based on AS-OCT images is proposed. Since the manual diagnosis mainly based on the morphology of each mechanism, in this study, a complete set of morphological features is extracted directly from raw AS-OCT images using compound image transforms, from which a small set of informative features with minimum redundancy are selected and fed into a Naïve Bayes Classifier (NBC). ResultsWe achieved an overall accuracy of 89.2% and 85.12% with a leave-one-out cross-validation and 10-fold cross-validation method, respectively. This study proposes a fully automated way for the classification of different ACG mechanisms, which is without intervention of doctors and less subjective when compared to the existing methods. ConclusionsWe directly extracted the compound image transformed features from the raw AS-OCT images without any segmentation and parameter measurement. Our method provides a completely automated and efficient way for the classification of different ACG mechanisms.

Complex wavelet based quality assessment for AS-OCT images with application to Angle Closure Glaucoma diagnosis

Background and objectivesAngle closure disease in the eye can be detected using time-domain Anterior Segment Optical Coherence Tomography (AS-OCT). The Anterior Chamber (AC) characteristics can be quantified from AS-OCT image, which is dependent on the image quality at the image acquisition stage. To date, to the best of our knowledge there are no objective or automated subjective measurements to assess the quality of AS-OCT images. MethodsTo address AS-OCT image quality assessment issue, we define a method for objective assessment of AS-OCT images using complex wavelet based local binary pattern features. These features are pooled using the Naïve Bayes classifier to obtain the final quality parameter. To evaluate the proposed method, a subjective assessment has been performed by clinical AS-OCT experts, who graded the quality of AS-OCT images on a scale of good, fair, and poor. This was done based on the ability to identify the AC structures including the position of the scleral spur. ResultsWe compared the results of the proposed objective assessment with the subjective assessments. From this comparison, it is validated that the proposed objective assessment has the ability of differentiating the good and fair quality AS-OCT images for glaucoma diagnosis from the poor quality AS-OCT images. ConclusionsThis proposed algorithm is an automated approach to evaluate the AS-OCT images with the intention for collecting of high quality data for further medical diagnosis. Our proposed quality index has the ability of automatic objective and quantitative assessment of AS-OCT image quality and this quality index is similar to glaucoma specialist.

Transient Ciliochoroidal Detachment After Ab Interno Trabeculotomy for Open-Angle Glaucoma: A Prospective Anterior-Segment Optical Coherence Tomography Study.

Although trabeculotomy is a glaucoma surgical procedure for modest intraocular pressure (IOP) reduction, some eyes exhibit very low IOP during the early postoperative period. To our knowledge, the reason and its effect have not been investigated. To investigate ciliochoroidal detachment (CCD) immediately after ab interno trabeculotomy and evaluate its effect on IOP immediately after surgery. This prospective, observational, case series was conducted at Kyoto University Hospital, Kyoto, Japan. Patients with open-angle glaucoma who underwent ab interno trabeculotomy using a microsurgical device by a single surgeon between July 1, 2014, and May 31, 2015, were included. Thirty-seven consecutive patients were enrolled, 33 of whom were included in the analysis. The dates of the analysis were August 1 to August 15, 2015. Imaging of CCD using anterior-segment optical coherence tomography (AS-OCT). The incidence of CCD immediately after ab interno trabeculotomy and its effect on IOP in the early postoperative period. The study cohort comprised 33 patients. Their mean (SD) age was 69.4 (13.2) years, and 19 (58%) were male. At postoperative day 3, CCD was detected in 14 of 33 eyes (42%) (CCD group) using AS-OCT. The CCD group had shorter axial length (mean [SD], 23.66 [1.67] vs 25.16 [1.59] mm) and thinner central corneal thickness (mean [SD], 505.9 [35.8] vs 533.9 [39.1] μm) than the non-CCD group. Only 5 eyes had CCD at postoperative day 10, and 4 of these eyes had CCD at 1 month after surgery. The postoperative IOPs at all follow-up periods were lower in the CCD group than in the non-CCD group, but the difference in the postoperative IOPs between the groups decreased as time passed. The mean (SD) IOPs for the CCD group vs the non-CCD group were 9.1 (3.0) vs 14.2 (5.8) mm Hg at day 1, 8.4 (2.4) vs 13.4 (5.0) mm Hg at day 3, 11.0 (3.0) vs 15.5 (6.3) mm Hg at day 10, 13.4 (2.4) vs 15.5 (3.3) mm Hg at 1 month, and 13.9 (3.4) vs 15.5 (4.0) mm Hg at 3 months. In several eyes in the CCD group, the AS-OCT images revealed a connection between the CCD and the anterior chamber via the trabeculotomy site. Ciliochoroidal detachment after ab interno trabeculotomy was not rare and was associated with low IOP immediately after surgery. Postoperative CCD may be partially attributed to the transient increase in uveoscleral aqueous outflow via the trabeculotomy site.

Agreement of angle closure assessments between gonioscopy, anterior segment optical coherence tomography and spectral domain optical coherence tomography.

To determine angle closure agreements between gonioscopy and anterior segment optical coherence tomography (AS-OCT), as well as gonioscopy and spectral domain OCT (SD-OCT). A secondary objective was to quantify inter-observer agreements of AS-OCT and SD-OCT assessments. Seventeen consecutive subjects (33 eyes) were recruited from the study hospital's Glaucoma clinic. Gonioscopy was performed by a glaucomatologist masked to OCT results. OCT images were read independently by 2 other glaucomatologists masked to gonioscopy findings as well as each other's analyses of OCT images. Totally 84.8% and 45.5% of scleral spurs were visualized in AS-OCT and SD-OCT images respectively (P<0.01). The agreement for angle closure between AS-OCT and gonioscopy was fair at k=0.31 (95% confidence interval, CI: 0.03-0.59) and k=0.35 (95% CI: 0.07-0.63) for reader 1 and 2 respectively. The agreement for angle closure between SD-OCT and gonioscopy was fair at k=0.21 (95% CI: 0.07-0.49) and slight at k=0.17 (95% CI: 0.08-0.42) for reader 1 and 2 respectively. The inter-reader agreement for angle closure in AS-OCT images was moderate at 0.51 (95% CI: 0.13-0.88). The inter-reader agreement for angle closure in SD-OCT images was slight at 0.18 (95% CI: 0.08-0.45). Significant proportion of scleral spurs were not visualised with SD-OCT imaging resulting in weaker inter-reader agreements. Identifying other angle landmarks in SD-OCT images will allow more consistent angle closure assessments. Gonioscopy and OCT imaging do not always agree in angle closure assessments but have their own advantages, and should be used together and not exclusively.

Repeatability and comparison of clinical techniques for anterior chamber angle assessment.

To assess the repeatability of gonioscopy, van Herick method and anterior segment Optical Coherence Tomography (AS-OCT) and determine the agreement between these techniques within a community optometry setting. Gonioscopy, van Herick method and AS-OCT imaging were performed by an optometrist on two occasions, 1month apart, on 80 subjects aged over 40years recruited from community optometry practices. Anterior segment images were captured with a spectral domain OCT (Topcon 3D OCT-2000; wavelength 840nm) set to the Anterior Segment (AS) mode. Eyes were graded as open or occludable for each method. AS-OCT images from both visits were graded by a second optometrist masked to the gonioscopy and van Herick method results, and the visit on which the images were acquired. Cohen's kappa (κ) was used to describe the intra-observer repeatability. Likelihood ratios, sensitivity and specificity of van Herick method and AS-OCT were calculated, using gonioscopy as the reference standard. Measurements were obtained from 80 eyes of 80 subjects. In four cases, AS-OCT images were un-gradable due to difficulty in locating the scleral spur. The repeatability of gonioscopy was fair κ=0.29, while that of the van Herick method (κ=0.54) and AS-OCT (κ=0.47) were somewhat better. The van Herick method showed good sensitivity (visit 1: 75%, visit 2: 69%) and high specificity (visit 1: 88%, visit 2: 96%). The sensitivity of AS-OCT was fair (visit 1: 46%, visit 2: 25%), but specificity was high (visit 1: 87%. visit 2: 89%). Intra-observer repeatability was better for van Herick method and for AS-OCT than for gonioscopy, despite the latter being considered the gold standard method. The van Herick method appeared to be more sensitive than AS-OCT when identifying eyes at risk of angle closure. A standalone anterior segment OCT with a longer wavelength laser could afford better visualisation of the angle, and might therefore be expected to enable the examiner to make more precise classifications. These instruments are not widely used by optometrists in clinical practice in the UK at present.

In Vivo Imaging of Radial Keratoneuritis in Patients with Acanthamoeba keratitis by Anterior-Segment Optical Coherence Tomography

To investigate in vivo corneal changes of radial keratoneuritis in early-stage Acanthamoeba keratitis (AK) using anterior-segment optical coherence tomography (AS-OCT). Single-center, prospective clinical study. Four eyes (4 patients with a mean age of 28.5 years) with early-stage AK showing radial keratoneuritis were included in this study. Definitive diagnosis was made by confirmation of AK cysts using in vivo confocal microscopy and culture. Anterior-segment OCT examination was performed on the initial visit and at follow-up visits paying special attention to radial keratoneuritis. Selected AS-OCT images of the cornea were evaluated qualitatively for the shape and degree of light reflection of abnormal neurons. With the use of AS-OCT, we successfully obtained high-resolution images of putative radial keratoneuritis in all patients as highly reflective bands or lines in the corneal stroma. The depth and width of the highly reflective bands/lines varied from case to case (anterior stroma to mid-stroma, from 20 to 200 μm). Some lines ran obliquely from the deep peripheral stroma toward the anterior stroma, and some were located at different depths (subepithelial and mid-stroma) and ran relatively parallel to the corneal layers. After appropriate treatment, radial keratoneuritis was resolved by both slit-lamp biomicroscopy and AS-OCT in all patients. High-resolution Fourier-domain AS-OCT provides novel and detailed visual information of radial keratoneuritis in patients with early-stage AK. Visualization of radial keratoneuritis by AS-OCT may be a useful adjunct to the diagnosis and follow-up of early-stage AK.

Longitudinal Changes of Angle Configuration in Primary Angle-Closure Suspects: The Zhongshan Angle-Closure Prevention Trial

To determine longitudinal changes in angle configuration in the eyes of primary angle-closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes. Longitudinal cohort study. Primary angle-closure suspects aged 50 to 70 years were enrolled in a randomized, controlled clinical trial. Each participant was treated by LPI in 1 randomly selected eye, with the fellow eye serving as a control. Angle width was assessed in a masked fashion using gonioscopy and anterior segment optical coherence tomography (AS-OCT) before and at 2 weeks, 6 months, and 18 months after LPI. Angle width in degrees was calculated from Shaffer grades assessed under static gonioscopy. Angle configuration was also evaluated using angle opening distance (AOD250, AOD500, AOD750), trabecular-iris space area (TISA500, TISA750), and angle recess area (ARA) measured in AS-OCT images. No significant difference was found in baseline measures of angle configuration between treated and untreated eyes. At 2 weeks after LPI, the drainage angle on gonioscopy widened from a mean of 13.5° at baseline to a mean of 25.7° in treated eyes, which was also confirmed by significant increases in all AS-OCT angle width measures (P<0.001 for all variables). Between 2 weeks and 18 months after LPI, a significant decrease in angle width was observed over time in treated eyes (P<0.001 for all variables), although the change over the first 5.5 months was not statistically significant for angle width measured under gonioscopy (P = 0.18), AOD250 (P = 0.167) and ARA (P = 0.83). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared with treated eyes (P values for all variables ≤0.003). The annual rate of change in angle width was equivalent to 1.2°/year (95% confidence interval [CI], 0.8-1.6) in treated eyes and 1.6°/year (95% CI, 1.3-2.0) in untreated eyes (P<0.001). Angle width of treated eyes increased markedly after LPI, remained stable for 6 months, and then decreased significantly by 18 months after LPI. Untreated eyes experienced a more consistent and rapid decrease in angle width over the same time period.

Comparison of morphologic features of clear corneal incisions created with a femtosecond laser or a keratome

To compare the morphology of clear corneal incisions (CCIs) created with a femtosecond laser (Catalys) or a keratome (2.65 mm steel) during phacoemulsification using anterior segment optical coherence tomography (AS-OCT) and analyze the intended versus the achieved morphologic characteristics of femtosecond laser-generated CCIs. Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. Comparative case series. Eyes with femtosecond CCIs and age-matched eyes with the keratome CCIs underwent AS-OCT of the incisions 1 month after phacoemulsification. ImageJ software was used to evaluate AS-OCT images for CCI length, endothelial gaping, endothelial misalignment, and Descemet membrane detachment. In the femtosecond group (20 eyes) and keratome group (16 eyes), the mean values were CCI length, 1.99 mm±0.07 (SEM) versus 2.04±0.23 mm (P=.39); endothelial gaping, 0.14±0.03 mm versus 0.19±0.09 mm (P=.03); endothelial misalignment, 0.04±0.03 mm versus 0.08±0.06 mm (P=.022). No eye in the femtosecond group and 3 eyes in the keratome group had a Descemet membrane detachment (P=.04). Six femtosecond eyes and 11 keratome eyes had posterior wound retraction (P=.02). The mean CCI length was 94.9% of the intended 2.1 mm, the posterior plane depth was 93.3% of the intended 70%, and the posterior side-cut angle was 91.7% of the intended 45 degrees. Femtosecond laser-generated CCIs had significantly lower endothelial gaping, endothelial misalignment, Descemet membrane detachment, and posterior wound retraction than keratome-created CCIs and were within 10% of the intended length, depth, and angle measurements. Neither author has a financial or proprietary interest in any material or method mentioned.

Anterior Segment Optical Coherence Tomography Changes to the Anterior Chamber Angle in the Short-term following Laser Peripheral Iridoplasty.

ABSTRACTPurpose: To evaluate, by anterior segment optical coherence tomography (AS-OCT), the changes in the anterior chamber angle during the short-term postoperative period after diode laser peripheral iridoplasty (LPI).Methods: Retrospective, observational study of consecutive primary angle closure suspect, primary angle closure, or primary angle closure glaucoma patients who underwent LPI. These patients had persistent iridotrabecular contact despite the presence of a patent peripheral iridotomy.The AS-OCT images of the temporal and nasal anterior chamber angles in dark conditions before and after LPI were ana lyzed. The main outcome measures were changed in AS-OCT parameters such as trabecular-iris angle (TIA), angle opening distance (AOD), trabecular-iris space area (TISA), trabecular-iris contact length (TICL), iris thickness (IT), and maximum iris bow height (MIBH). Secondary outcome para meters included intraocular pressure (IOP) and postlaser complications.Results: Images of 14 eyes of 14 patients were assessed. The mean time from LPI to the follow-up AS-OCT scan was 6 ± 3 weeks. The IT did not alter significantly after LPI, but there were significant increases in the TIA, AOD and TISA, as well as a significant decrease in TICL and MIBH. There were no significant postlaser complications. There was a small decrease in mean IOP from 17.1 ± 4.0 mm Hg to 14.8 ± 4.6 mm Hg (p = 0.014).Conclusion: Based on AS-OCT imaging, LPI resulted in significant angle widening and iris profile fattening during the short-term postoperative period in eyes with persistent angle closure despite the presence of a patent peripheral iridotomy.How to cite this article: Leong JCY, O'Connor J, Ang GS, Wells AP. Anterior Segment Optical Coherence Tomography Changes to the Anterior Chamber Angle in the Short-term following Laser Peripheral Iridoplasty. J Current Glau Prac 2014;8(1):1-6.

Glaucoma Tube Imaging Using Anterior Segment Optical Coherence Tomography in Patients With Opaque Cornea

Anterior segment optical coherence tomography (AS-OCT) was used to diagnose Ahmed tube tip patency in patients with opaque corneas after corneal transplantation and tube shortening. Noncomparative observational case series: 3 consecutive patients with nonvisualized tubes and uncontrolled intraocular pressure after corneal transplantation underwent AS-OCT to determine tube tip patency. In each case, AS-OCT allowed for imaging of the tube position, wall passage, and osteum patency that could not be visualized on gonioscopy. Two of 3 tubes were found to be nonpatent. High-resolution noncontact cross-sectional AS-OCT images provide information on tube position and patency in the presence of opaque media after corneal transplantation, assisting with clinical decision-making.

Epithelial Downgrowth After Penetrating Keratoplasty

To report the clinical utility of high-resolution anterior segment optical coherence tomography (AS-OCT) combined with in vivo confocal microscopy (IVCM) to diagnose and follow the effectiveness of treatment of 2 cases of epithelial downgrowth after penetrating keratoplasty. A retrospective case review was performed on 2 eyes of 2 patients with a history of multiple penetrating keratoplasties that developed epithelial downgrowth 4 and 6 months after the most recent penetrating graft. At various time points, high-resolution AS-OCT images were obtained using the Spectralis (Heidelberg Engineering GmbH), and IVCM images were obtained using the Heidelberg Retina Tomograph III Rostock Cornea Module (Heidelberg Engineering GmbH). In 1 case, the diagnosis was confirmed by histopathologic evaluation. Two patients developed epithelial downgrowth after penetrating keratoplasty. In case 1, a 48-year-old man with a history of Acanthamoeba keratitis developed epithelial downgrowth after undergoing 2 therapeutic grafts over a 1-year period. In case 2, a 40-year-old man with a history of a corneal laceration complicated by fungal keratitis was diagnosed with epithelial downgrowth after undergoing 3 penetrating grafts, the placement of a glaucoma drainage device, and a pars plana vitrectomy over a 3-year period. In both cases, at the level of the endothelium, AS-OCT identified a highly reflective layer and IVCM revealed round hyperreflective nuclei consistent with epithelium. Epithelial downgrowth is an uncommon complication after penetrating keratoplasty. High-resolution AS-OCT and IVCM are noninvasive imaging modalities that may potentially be more sensitive in identifying and monitoring epithelial downgrowth than routine light biomicroscopy and may obviate the need for invasive diagnostic measures.