Anterior Segment Optical Coherence Tomography Findings Research Articles

Can preoperative anterior segment optical coherence tomography predict posterior capsule rupture during phacoemulsification in patients with posterior polar cataract?

To determine whether preoperative assessment of posterior capsule integrity using anterior segment optical coherence tomography (AS-OCT) can predict posterior capsule dehiscence in patients with posterior polar cataract having phacoemulsification. Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Pondicherry, India. Prospective observational study. Patients with posterior polar cataract who had phacoemulsification between October 2012 and November 2013 were included in the study. Preoperative AS-OCT imaging was performed to assess the integrity of the posterior capsule. Anterior segment OCT images of the posterior capsule were graded as "intact" or "dehiscent." Phacoemulsification was performed by the same surgeon who was masked from the AS-OCT findings. The integrity of the posterior capsule was evaluated by the surgeon intraoperatively. The study comprised 64 eyes of 62 patients. Preoperative AS-OCT showed 8 eyes (12.5%) to have probable posterior capsule dehiscence and 56 eyes (87.5%) to have intact posterior capsules. Intraoperatively, the surgeon noted posterior capsule dehiscence in 5 eyes (7.8%) and an intact posterior capsule in 59 eyes (92.2%). The sensitivity and specificity of AS-OCT for detecting posterior capsule dehiscence was 100% and 94.92%, respectively. The negative predictive value of AS-OCT was 100%. Anterior segment OCT with its high negative predictivevalue can be used successfully to predict the risk for posteriorcapsule rupture during phacoemulsification in eyes with posterior polar cataract.

Evaluation of Iris Melanoma with Anterior Segment Optical Coherence Tomography.

Anterior segment optical coherence tomography (AS-OCT) is a relatively new imaging modality that allows assessment of anterior segment structures. AS-OCT enables the differentiation of benign and malignant tumors through the evaluation of lesion size, internal structure, degree of vascularity, and anterior and posterior surfaces. Herein, we discuss the AS-OCT findings of a patient with spindle type iridociliary melanoma diagnosed in pathologic examination.

Evaluation of Kayser-Fleischer ring in Wilson disease by anterior segment optical coherence tomography.

Purpose:The purpose of the study is to present anterior segment optical coherence tomography (AS-OCT) as an alternative method of evaluating Kayser–Fleischer (KF) ring in Wilson disease (WD) not only by ophthalmologists but also by other clinicians dealing with WD.Materials and Methods:This was a retrospective case series of six WD patients with KF ring. Evaluation of KF ring was done by naked eye examination using torch light, slit lamp biomicroscopy (SL), and AS-OCT. SL examination was done using a narrow slit of the superior cornea. AS-OCT was done using the Optovue RTvue Premier™ device (Fremont, CA, USA).Results:AS-OCT revealed KF ring as an intense hyperreflective band at the level of Descemet membrane (DM). Color scale of AS-OCT showed KF ring as greenish/greenish yellow/orange yellow/yellowish/red band. Validation of AS-OCT findings was done by second ophthalmologist, medical gastroenterologist, surgical gastroenterologist, and neurophysician. After seeing the first observation, they could identify the AS-OCT features in all pictures with ease.Conclusions:This is the first observation of KF ring in WD on AS-OCT. On AS-OCT, KF ring is visualized as intense hyperreflectivity at the level of DM in the peripheral cornea. Further, studies are needed to evaluate the usefulness of AS-OCT in WD management.

Diagnostic capabilities of optical coherence tomography and confocal laser scanning microscopy in studying manifestations of aniridia-associated keratopathy

to investigate the possible use of anterior segment optical coherence tomography (AS-OCT) and laser scanning confocal microscopy (LSCM) for visualization of limbal progenitor structures and epithelial changes at different stages of aniridia-associated keratopathy (AAK) and to analyze genotype-phenotype correlations of corneal damage. Thirty-four patients (63 eyes) with congenital aniridia (CA) were subjected to epithelial cell density measurement in the central cornea as well as epithelial surface assessment with limbal palisades of Vogt (POV) detection in the corresponding sites of the two corneas. For that, LSCM (HRT3) and AS-OCT (RTVue XR Avanti) were performed. Central corneal and epithelial thicknesses were measured using the Pachymetry protocol. There has been found an increase in the central corneal thickness (CCT) of CA patients, which correlated with the stage of AAK, and a decrease in the central epithelial thickness as compared with healthy subjects (p<0.05). The difference between the basal and wing epithelial cells density in eyes with stages I and II AAK and normal cells density at stage 0 AAK was statistically significant (p<0.05). Intact or disturbed POV were detected in all patients with PAX6 3' deletion. At that, AS-OCT findings highly agreed with LSCM images for both the inferii (rS=0.85, p<0.05) and superior limbi (rS=0.53, p<0.05). A negative correlation was established between the stage of AAK and in vivo morphology of POV (rS=-0.5, p<0.05). However, no correlation was found between the stage of AAK and patient's age (rS=0.169, p=0.174). AS-OCT and LSCM are both important diagnostic tools for corneal surface monitoring in patients with limbal stem cells deficiency.

The role of anterior segment optical coherence tomography in the management of an intra-corneal foreign body.

IntroductionCorneal foreign bodies are reported to be the second most common type of ocular injury. Anterior segment optical coherence tomography (AS-OCT) is a valuable tool for the early diagnosis and monitoring the progress of treatment in cases of ocular trauma. Herein we aimed to report on a patient with an intra-corneal foreign body and the role of AS-OCT in management.Case presentationA 34-year-old male presented with foreign body sensation in his left eye. Slit-lamp biomicroscopic examination revealed a peripherally located intrastromally embedded foreign body with a free anterior edge extending outwards from the cornea. It was not possible to visualize the foreign body’s entire route through the cornea because of localized corneal edema. AS-OCT showed shadowing of the corneal layers corresponding to the location of the corneal foreign body. A hyper-reflective lesion was observed close to the inside edge of the foreign body in the cornea, indicating that the foreign body had not completely penetrated the cornea. The foreign body was removed via the external route, as it had not completely penetrated the cornea. During the postoperative period the patient was asymptomatic, although the left eye’s cornea healed with scar tissue. Discussion and EvaluationAS-OCT facilitates non-invasive rapid imaging of ocular tissue at va rious depths, thereby providing accurate assessment of foreign body characteristics.The location of an intracorneal foreign body and the status of the surrounding ocular structure dictate the optimal surgical technique to be employed.ConclusionsAS-OCT in the present case facilitated localization and determination of the size of a corneal foreign body. In addition, AS-OCT findings assisted in selection of the appropriate surgical intervention.

Anterior segment optical coherence tomography for demonstrating posterior capsular rent in posterior polar cataract

Aims/purposeTo report the preoperative use of anterior segment optical coherence tomography (AS-OCT) for the determination of pre-existing posterior capsule defect in patients with posterior polar cataract.MethodsThree patients presented with posterior polar cataract and were evaluated preoperatively using AS-OCT, revealing in one patient intact posterior capsule and in the other two a pre-existing posterior capsule defect not detectable by slit-lamp evaluation. All patients underwent phacoemulsification and intraocular lens implantation.ResultsIntraoperatively, AS-OCT findings were confirmed after cataract surgery in all patients. No intra- or late postoperative complications were noted.ConclusionAS-OCT could be an additional useful imaging modality in these patients, essential for surgical planning and patient consultation.

Anterior segment optical coherence tomography findings of iris granulomas in Hansen's disease: a case report

BackgroundA 50-year-old male was diagnosed to have a right eye sclerouveitis and left eye granulomatous anterior uveitis due to Hansen's disease. We are reporting the anterior segment optical coherence tomography (ASOCT) findings of iris granuloma in this case.FindingsSkin biopsy revealed plenty of acid fast bacilli with a bacteriological index of 5 suggestive of multibacillary polar lepromatous leprosy. ASOCT revealed well-demarcated smooth-surfaced nodular lesion with internal hyporeflectivity corresponding to the areas of granuloma which decreased in size following treatment with antileprosy drugs and systemic and topical steroids.ConclusionASOCT is a non-invasive technique to assess the extent of involvement of anterior segment in Hansen's disease and is a useful tool in follow-up. This is also the first report on ASOCT findings of iris granuloma in Hansen's disease.

Age-Related Changes in Trabecular Meshwork Imaging

Purpose. To evaluate the normal aging effects on trabecular meshwork (TM) parameters using Fourier domain anterior segment optical coherence tomography (ASOCT) images. Patients and Methods. One eye from 45 participants with open angles was imaged. Two independent readers measured TM area, TM length, and area and length of the TM interface shadow from 3 age groups (18–40, 41–60, and 61–80). Measurements were compared using stepwise regression analysis. Results. The average TM parameters were 0.0487 (±0.0092) mm2 for TM area, 0.5502 (±0.1033) mm for TM length, 0.1623 (±0.341) mm2 for TM interface shadow area, and 0.7755 (±0.1574) mm for TM interface shadow length. Interobserver reproducibility coefficients ranged from 0.45 (TM length) to 0.82 (TM area). TM area and length were not correlated with age. While the TM interface shadow length did not correlate with age, the TM interface shadow area increased with age. Race, sex, intraocular pressure, and gonioscopy score were not correlated with any TM parameters. Conclusion. Although the TM measurements were not correlated with age, the TM interface shadow area increased with age. Further study is required to determine whether there is any relationship between the age-related ASOCT findings of the TM interface shadow area and physiologic function.

Anterior Segment Optical Coherence Tomography–Guided Big-Bubble Technique

To evaluate the feasibility of intraoperative anterior segment (AS) optical coherence tomography (OCT) for quantification of the corneal depth reached with the dissecting cannula used for deep anterior lamellar keratoplasty, as well as its correlation with the success rate of big-bubble formation. Retrospective, noncomparative, interventional case series. One hundred consecutive keratoconus patients. Deep anterior lamellar keratoplasty was performed using the big-bubble technique. During surgery, the cannula used for pneumatic dissection was inserted into the peripheral stroma and advanced as deep and far toward the center as believed adequate by the surgeon. Then, after retracting the cannula, AS OCT was performed. The cannula was placed back in position and creation of the big bubble was attempted. Stromal depth reached with the cannula tip, success rate in achieving big-bubble formation, and complication rate. Bubble formation was obtained in 70 of 100 eyes (70%). In all remaining eyes, the procedure was completed by manual deep lamellar dissection. The average depth reached by the cannula tip was 104.3±34.1 μm from the internal corneal surface; the mean value recorded in cases of successful big-bubble formation (90.4±27.7 μm) was statistically lower than that measured in failed procedures (136.7±24.2 μm). In 1 case, corneal perforation occurred during the insertion of the cannula and required conversion to penetrating keratoplasty (PK). In 8 eyes, small microperforations occurred during stromal excision but could be managed conservatively, avoiding conversion to PK. In 2 advanced cones, an incomplete bubble formation was obtained, necessitating manual peripheral stromal removal. Successful big-bubble formation can be anticipated if pneumatic dissection is attempted at a sufficiently deep level. Although an ideal depth could not be defined, AS OCT allows objective evaluation of the depth reached by the cannula tip used for pneumatic dissection. The AS OCT findings may confirm the decision to proceed with air injection. It is possible that cannula repositioning based on the AS OCT depth may improve the success rate for big-bubble formation.

Anterior Segment Optical Coherence Tomography in Congenital Corneal Opacities

To evaluate the clinical usefulness of anterior segment (AS) optical coherence tomography (OCT) in diagnosis and follow-up of children with congenital corneal opacities. Noncomparative case series. Seven consecutive patients with bilateral congenital corneal opacity between 2 days and 2.5 years of age. In addition to basic outpatient examination, eyes were imaged using AS OCT. Anterior segment structures and corneal thicknesses were evaluated from the images. Three children also underwent evaluation under anesthesia, including measurement of corneal thickness with ultrasound pachymetry. Evaluation of the type and severity of the congenital corneal opacity based on the findings in AS OCT. Thirteen of the 14 eyes could be imaged using AS OCT. The youngest patient studied was only 2 days old. Three distinct phenotypes were found based on the AS OCT findings. Three patients with iridocorneal adhesions were deduced to have type 1 Peters' anomaly, and 2 patients with lenticulocorneal adhesions were deduced to have type 2 Peters' anomaly. The 2 youngest patients had complete corneal opacity with features of corneal staphyloma and marked changes in the AS structures during the first months of life. Anterior segment OCT was a valuable method in the diagnosis and follow-up of patients with congenital corneal opacities. As a fast and noncontact technique, it was applicable even for neonates. It allowed early characterization of the type and the extent of the AS disorder. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Anterior Segment Optical Coherence Tomography Features of Acute Corneal Hydrops

To describe the clinical significance of in vivo corneal findings in eyes with acute corneal hydrops. Medical records and anterior segment optical coherence tomography (ASOCT) images of 24 patients with keratoconus and unilateral acute corneal hydrops were reviewed. Clinical findings and position, integrity, and orientation of the Descemet membrane (DM) on ASOCT were noted. Size of the DM break, depth of the DM detachment, and corneal thickness were measured by ASOCT and correlated with the duration of corneal edema, assessed clinically. Outcomes of intracameral perfluoropropane (C(3)F(8)) gas in 13 eyes and histopathological findings after penetrating keratoplasty in 2 eyes were also correlated with serial ASOCT findings. Duration of corneal edema was 9.3 ± 4.4 weeks. On ASOCT, DM showed 3 patterns: detachment with break and rolled ends (n = 13), detachment with break and flat ends (n = 10), and detachment with no break (n = 1). Initial corneal thickness was 1.3 ± 0.25 mm, size of the DM break was 1.1 ± 0.8 mm, and depth of the DM detachment was 0.9 ± 0.6 mm. On multiple regression analysis, duration of corneal edema showed significant positive association with the depth of DM detachment (P = 0.0002) and size of DM break (P = 0.002) and negative association with intracameral C3F8 (P < 0.0001). Correlation of ASOCT with histopathological findings revealed 2 stages of resolution of hydrops: reattachment of DM and endothelial migration. Eyes with deeper DM detachments and larger DM breaks required more time for resolution of corneal edema despite intracameral C(3)F(8). This association needs to be validated by a prospective study.

Diagnostic Performance of Anterior Chamber Angle Measurements for Detecting Eyes With Narrow Angles

To assess the diagnostic performance of angle measurements from anterior segment optical coherence tomography (AS-OCT) images for identifying eyes with narrow angles. We conducted a community-based cross-sectional study of individuals 50 years or older who had phakic eyes and who underwent AS-OCT imaging in the dark by a single operator and gonioscopy by an ophthalmologist masked to AS-OCT findings. An eye was considered to have narrow angles if the posterior pigmented trabecular meshwork was not visible for at least 180° on gonioscopy. Horizontal AS-OCT images were analyzed for the following measurements using customized software: angle opening distance (AOD) at 250, 500, and 750 μm from the scleral spur; trabecular-iris space area (TISA) at 500 and 750 μm; and angle recess area (ARA) at 750 μm. Areas under the receiver operating characteristic curves (AUCs) were generated for AOD, TISA, and ARA to assess the performance of these measurements in detecting eyes with narrow angles. Of 2047 individuals examined, 582 were excluded mostly because of poor image quality or inability to locate the scleral spur. Of the remaining 1465 participants, 315 (21.5%) had narrow angles on gonioscopy. Mean (SD) age was 62.7 (7.7) years, 54.1% were women, and 90.0% were Chinese. The AUCs were highest for AOD750 in the nasal (0.90 [95% confidence interval, 0.89-0.92]) and temporal (0.91 [0.90-0.93]) quadrants. The AOD750 is the most useful angle measurement for identifying individuals with gonioscopic narrow angles in gradable AS-OCT images. Poor definition of the scleral spur precludes quantitative analysis in approximately 25% of AS-OCT images.

Utility of Bleb Imaging With Anterior Segment Optical Coherence Tomography in Clinical Decision-making After Trabeculectomy

To determine if imaging of blebs with anterior segment optical coherence tomography (ASOCT) affects clinical decision-making with regard to laser suture lysis (LSL) after trabeculectomy. In this prospective observational case series, we included patients with poorly controlled intraocular pressure (IOP) after standardized trabeculectomy from May to November 2006. One observer assessed IOP, anterior chamber depth and bleb formation, and recorded a decision of whether or not to undertake LSL based on clinical grounds. A second observer masked to clinical data recorded a decision of whether or not to perform LSL based on ASOCT assessment of scleral flap position, presence of a sub-flap space, patency of the internal ostium, and bleb wall thickening. We compared the 2 observers' decisions to determine how ASOCT influenced decision-making. Seven eyes of 7 patients were included. On the basis of clinical examination, LSL was recommended in all 7 (100.0%) cases due to presence of elevated IOP, deep anterior chambers and poorly formed blebs. Using ASOCT, LSL was recommended in 5/7 (71.4%) cases with apposed scleral flaps, absent sub-flap spaces, and absent bleb wall thickening. In 2/7 (28.7%) cases, LSL was not recommended based on ASOCT findings of an elevated scleral flap, a patent sub-flap space, and bleb wall thickening. All 7 patients had good IOP control and formed blebs at a mean of 8.4+/-2.6 months after trabeculectomy, with a mean IOP of 14.3+/-3.2 mm Hg with no medications. This small study suggests that ASOCT imaging may affect decision-making with regard to LSL by providing information not apparent on clinical examination.

Comparison of Visante and slit-lamp anterior segment optical coherence tomography in imaging the anterior chamber angle

To compare the diagnostic performance of two anterior segment optical coherence tomography (AS-OCT) devices in assessing the anterior chamber angle (ACA). Visante-OCT and slit-lamp-OCT (SL-OCT) were performed on 101 patients by a single operator. The AS-OCT images were processed by customised 'dewarping' software and assessed by two glaucoma specialists masked to clinical findings. A closed ACA was defined by the presence of contact between the iris and angle anterior to the scleral spur. Measurements of the ACA, anterior chamber depth (ACD), and pupil diameter were analysed. Gonioscopy was performed by another examiner masked to AS-OCT findings. Qualitative analysis could be carried out in 83 (83%) eyes and quantitative analysis in 61 (60%) eyes. A closed angle in at least one quadrant of the eye was observed in 30 eyes with gonioscopy; Visante-OCT imaging identified 29 of 30 (97%) and SL-OCT imaging identified 27 of 30 (90%) of these eyes (P=0.50, McNemar test). Visante-OCT detected more eyes with at least one closed quadrant than SL-OCT (55 vs46 eyes, respectively, P=0.01). Overall, SL-OCT had better agreement with gonioscopy than with Visante-OCT. Both AS-OCTs showed good agreement for ACD measurements; however, SL-OCT tended to provide consistently higher ACA measurements and smaller pupil diameters than did Visante-OCT. Both AS-OCT devices detected most of the eyes with closed ACA on gonioscopy. However, Visante-OCT detected more closed ACAs than did SL-OCT. The better agreement between SL-OCT and gonioscopy is likely because of the use of visible light during both examinations. The ACA measurements obtained with each device are not interchangeable.

Comparison of a torsional handpiece through microincision versus standard clear corneal cataract wounds

To directly compare intraoperative and clinical parameters using a torsional handpiece through microincision and standard clear corneal cataract wounds with appropriately configured tips and sleeves. Duke University Eye Center, Durham, North Carolina, USA. Cataracts in both eyes of 32 patients needing bilateral surgery were extracted using the OZil torsional handpiece. Tips and sleeve selections were optimized for the incision chosen. Right eyes had cataract surgery using a standard method consisting of a 2.8 mm incision with a 0.9 mm tapered 30-degree bevel Kelman configuration tip with a Microsleeve. Left eyes had cataract surgery through a 2.2 mm microincision using a 0.9 mm miniflared 45-degree bevel Kelman configuration tip with an Ultrasleeve. Intraoperative measurements included cumulative dissipated energy (CDE) and balanced salt solution use. Clinical measurements included preoperative and 1-day postoperative central corneal thickness (CCT), preoperative and 6-month postoperative endothelial cell count (ECC), and preoperative and postoperative anterior segment optical coherence tomography (AS-OCT). Intraoperatively, the microincision (2.2 mm) group had less CDE use than the standard incision (2.8 mm) group (P= .001). Clinical measurements showed less ECC loss at 6 months in the microincision group (P<.05). No difference in CCT or AS-OCT findings was detected between groups. Phacoemulsification using the OZil torsional handpiece through a microincision with an Ultrasleeve and a 45-degree miniflared tip showed favorable clinical and intraoperative characteristics such as less total energy use and less endothelial cell loss at 6 months. Further studies are warranted to substantiate these preliminary findings.

Comparison of Gonioscopy and Anterior Segment Ocular Coherence Tomography in Detecting Angle Closure in Different Quadrants of the Anterior Chamber Angle

To compare the performance of gonioscopy and anterior segment (AS) optical coherence tomography (OCT) in detecting angle closure in the different quadrants of the anterior chamber angle (ACA). Cross-sectional observational study. Five hundred two consecutive subjects more than 50 years of age with no previous ophthalmic problems recruited from a community clinic in Singapore. All subjects underwent gonioscopy and AS OCT imaging in the dark. Using gonioscopy, the ACA was graded using the Scheie system by a single examiner masked to AS OCT findings. The ACA in a particular quadrant was classified as closed if the posterior trabecular meshwork could not be seen on gonioscopy. A closed ACA on AS OCT imaging was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. After excluding eyes with poor image quality, a total of 423 right eyes were included in the analysis. A closed angle in at least 1 quadrant was observed in 59% of the eyes by AS OCT and in 33% of the eyes by gonioscopy (P<0.001), with fair agreement between the two methods (kappa = 0.40). The frequency of closed angles by AS OCT and gonioscopy were 48% versus 29% superiorly, 43% versus 22% inferiorly, 18% versus 14% nasally, and 12% versus 20% temporally, respectively. Of the 119 of 1692 quadrants that were closed on gonioscopy but open on AS OCT, a steep iris profile was present in 61 (51%) of 119 quadrants on AS OCT, and of the 276 of 1692 quadrants that were open on gonioscopy but closed on AS OCT, 196 (71%) of 276 quadrants showed short iridoangle contact on AS OCT. The highest rates of closed angles on gonioscopy and AS OCT images were observed in the superior quadrant. Anterior segment OCT tended to detect more closed ACAs than gonioscopy, particularly in the superior and inferior quadrants. Variations in the iris profile and level of iridoangle contact also may explain some of the differences seen between gonioscopy and AS OCT.

Degree of angle closure and extent of peripheral anterior synechiae: an anterior segment OCT study

Aims:To evaluate the relationship between angle width as determined by anterior segment optical coherence tomography (AS-OCT) and the presence of peripheral anterior synechiae (PAS).Methods:This was a prospective observational case series...