The African Descent and Glaucoma Evaluation Study (ADAGES) III: Contribution of Genotype to Glaucoma Phenotype in African Americans: Study Design and Baseline Data.

PURPOSE: To describe the study protocol and baseline characteristics of the African Descent and Glaucoma Evaluation Study (ADAGES) III. DESIGN: Cross-sectional, case-control study. PARTICIPANTS: Three thousand two hundred sixty-six glaucoma patients and control participants without glaucoma of African or European descent were recruited from 5 study centers in different regions of the United States. METHODS: Individuals of African descent (AD) and European descent (ED) with primary open-angle glaucoma (POAG) and control participants completed a detailed demographic and medical history interview. Standardized height, weight, and blood pressure measurements were obtained. Saliva and blood samples to provide serum, plasma, DNA, and RNA were collected for standardized processing. Visual fields, stereoscopic disc photographs, and details of the ophthalmic examination were obtained and transferred to the University of California, San Diego, Data Coordinating Center for standardized processing and quality review. MAIN OUTCOME MEASURES: Participant gender, age, race, body mass index, blood pressure, history of smoking and alcohol use in POAG patients and control participants were described. Ophthalmic measures included intraocular pressure, visual field mean deviation, central corneal thickness, glaucoma medication use, or past glaucoma surgery. Ocular conditions, including diabetic retinopathy, age-related macular degeneration, and past cataract surgery, were recorded. RESULTS: The 3266 ADAGES III study participants in this report include 2146 AD POAG patients, 695 ED POAG patients, 198 AD control participants, and 227 ED control participants. The AD POAG patients and control participants were significantly younger (both, 67.4 years) than ED POAG patients and control participants (73.4 and 70.2 years, respectively). After adjusting for age, AD POAG patients had different phenotypic characteristics compared with ED POAG patients, including higher intraocular pressure, worse visual acuity and visual field mean deviation, and thinner corneas (all P < 0.001). Family history of glaucoma did not differ between AD and ED POAG patients. CONCLUSIONS: With its large sample size, extensive specimen collection, and deep phenotyping of AD and ED glaucoma patients and control participants from different regions in the United States, the ADAGES III genomics study will address gaps in our knowledge of the genetics of POAG in this high-risk population.

Genetic Architecture of Primary Open-Angle Glaucoma in Individuals of African Descent: The African Descent and Glaucoma Evaluation Study III.

PURPOSE: To find genetic contributions to glaucoma in African Americans. DESIGN: Cross-sectional, case-control study. PARTICIPANTS: One thousand eight hundred seventy-five primary open-angle glaucoma (POAG) patients and 1709 controls, self-identified as being of African descent (AD), from the African Descent and Glaucoma Evaluation Study (ADAGES) III and Wake Forest School of Medicine. METHODS: MegaChip genotypes were imputed to Thousand Genomes data. Association of single nucleotide polymorphisms (SNPs) with POAG and advanced POAG was tested by linear mixed model correcting for relatedness and population stratification. Genetic risk scores were tested by receiver operator characteristic curves (ROC-AUCs). MAIN OUTCOME MEASURES: Primary open-angle glaucoma defined by visual field loss without other nonocular conditions (n = 1875). Advanced POAG was defined by age-based mean deviation of visual field (n = 946). RESULTS: Eighteen million two hundred eighty-one thousand nine hundred twenty SNPs met imputation quality of r2 > 0.7 and minor allele frequency > 0.005. Association of a novel locus, EN04, was observed for advanced POAG (rs185815146 ß, 0.36; standard error, 0.065; P < 3×10-8). For POAG, an AD signal was observed at the 9p21 European descent (ED) POAG signal (rs79721419; P < 6.5×10-5) independent of the previously observed 9p21 ED signal (rs2383204; P < 2.3×10-5) by conditional analyses. An association with POAG in FNDC3B (rs111698934; P < 3.9×10-5) was observed, not in linkage disequilibrium (LD) with the previously reported ED SNP. Additional previously identified loci associated with POAG in persons of AD were: 8q22, AFAP1, and TMC01. An AUC of 0.62 was observed with an unweighted genetic risk score comprising 11 SNPs in candidate genes. Two additional risk scores were studied by using a penalized matrix decomposition with cross-validation; risk scores of 50 and 400 SNPs were identified with ROC of AUC = 0.74 and AUC = 0.94, respectively. CONCLUSIONS: A novel association with advanced POAG in the EN04 locus was identified putatively in persons of AD. In addition to this finding, this genome-wide association study in POAG patients of AD contributes to POAG genetics by identification of novel signals in prior loci (9p21), as well as advancing the fine mapping of regions because of shorter average LD (FNDC3B). Although not useful without confirmation and clinical trials, the use of genetic risk scores demonstrated that considerable AD-specific genetic information remains in these data.

Characterizing Anterior Segment OCT Angle Landmarks of the Trabecular Meshwork Complex.

PURPOSE: To identify the presence or absence of 3 identifiable landmarks: trabecular meshwork (TM), Schlemm's canal (SC), and a novel landmark termed the band of extracanalicular limbal lamina (BELL), which is a landmark adjacent to SC visible on anterior segment (AS) OCT. These landmarks also were analyzed pathologically to identify all 3 landmarks. DESIGN: Retrospective review. PARTICIPANTS: One eye per participant from prior institutional review board-approved studies in which AS OCT imaging was performed. METHODS: Horizontal images from 2-dimensional angle analysis scans using a CASIA SS-1000 (Tomey, Nagoya, Japan) AS OCT were evaluated by masked readers. Logistic regression was used to analyze the potential factors of age, gender, race, intraocular pressure, gonioscopy grade, angle location, and history or presence of surgery on the visibility of these structures. Pathologic correlation on 5 previously enucleated eyes also was performed. MAIN OUTCOME MEASURES: Presence or absence of angle landmarks-TM, SC, and BELL-using Anterior Chamber Analysis and Interpretation software (ACAI, Houston, TX). RESULTS: Three hundred three angles of 153 horizontal images were included in this study. The mean age was 51.5±16.0 years, with 98 women (64%) and 100 white persons (66%). The outer border of the BELL was observed in 288 angles (95%), TM was found in 220 angles (73%), and SC was seen in 120 angles (40%). The outer border of the BELL was more visible in white persons (P = 0.02) than Asians and in eyes with a Spaeth gonioscopy grade of E than those with a grade of A (P = 0.02). Both TM (P = 0.001) and SC (P = 0.001) were more visible in temporal angles (81% for TM, 49% for SC) than in nasal angles (64% for TM, 30% for SC). Additionally, SC was more visible in open angles (43%) than in narrow angles (27%; P = 0.02). These 3 structures were verified in a pathologic study. CONCLUSIONS: We identified a novel AS OCT landmark adjacent to SC. This structure also was identified on pathologic samples from enucleated eyes. Further study is needed to determine the pathophysiologic relevance of these findings.

Direct Costs of Second Aqueous Shunt Implant Versus Transscleral Cyclophotocoagulation (The Assists Trial).

PRCIS: The cost of cyclophotocoagulation is less than the cost of a second glaucoma drainage device. PURPOSE: To compare the total direct costs of implantation of a second glaucoma drainage device (SGDD) with transscleral cyclophotocoagulation (CPC) for patients with inadequately controlled intraocular pressure (IOP) reduction, despite the presence of a preexisting glaucoma drainage device in the ASSISTS clinical trial. METHODS: We compared the total direct cost per patient, including the initial study procedure, medications, additional procedures, and clinic visits during the study period. The relative costs for each procedure during the 90-day global period and the entire study period were compared. The cost of the procedure, including facility fees and anesthesia costs, were determined using the 2021 Medicare fee schedule. Average wholesale prices for self-administered medications were obtained from AmerisourceBergen.com. The Wilcoxon rank sum test was used to compare costs between procedures. RESULTS: Forty-two eyes of 42 participants were randomized to SGDD (n=22) or CPC (n=20). One CPC eye was lost to follow-up after initial treatment and was excluded. The mean (±SD, median) duration of follow-up was 17.1 (±12.8, 11.7) months and 20.3 (±11.4, 15.1) months for SGDD and CPC, respectively ( P =0.42, 2 sample t test). The mean total direct costs (±SD, median) per patient during the study period were $8790 (±$3421, $6805 for the SGDD group) and $4090 (±$1424, $3566) for the CPC group ( P <0.001). Similarly, the global period cost was higher in the SGDD group than in the CPC group [$6173 (±$830, $5861) vs. $2569 (±$652, $2628); P <0.001]. The monthly cost after the 90-day global period was $215 (±$314, $100) for SGDD and $103 (±$74, $86) for CPC ( P =0.31). The cost of IOP-lowering medications was not significantly different between groups during the global period ( P =0.19) or after the global period ( P =0.23). CONCLUSION: The total direct cost in the SGDD group was more than double that in the CPC group, driven largely by the cost of the study procedure. The costs of IOP-lowering medications were not significantly different between groups. When considering treatment options for patients with a failed primary GDD, clinicians should be aware of differences in costs between these treatment strategies.

Outcomes of the Second Aqueous Shunt Implant Versus Transscleral Cyclophotocoagulation Treatment Study: A Randomized Comparative Trial.

PRCIS: Short-term overall success rates were high with either SGDD or CPC. However, SGDD was associated with more clinic visits and an increased risk of additional glaucoma surgery. Both treatments were reasonable options for eyes with inadequately controlled IOP after a single GDD. PURPOSE: The purpose of this study is to compare the implantation of a second glaucoma drainage device (SGDD) and transscleral cyclophotocoagulation (CPC) in eyes with inadequately controlled intraocular pressure (IOP), despite the presence of a preexisting glaucoma drainage device. METHODS: Patients with inadequately controlled IOP, despite the medical therapy and a preexisting glaucoma drainage device, were enrolled at 14 clinical centers and randomly assigned to treatment with a SGDD or CPC. MAIN OUTCOME MEASURES: Surgical failure was defined as: (1) IOP ≤5 mm Hg or >18 mm Hg or <20% reduction below baseline on maximum tolerated topical ocular hypotensive therapy, (2) reoperation for glaucoma, or (3) loss of light perception. The primary outcome measure was overall success with or without adjunctive medical therapy. RESULTS: Forty-two eyes of 42 participants were randomized to SGDD (n=22) or CPC (n=20). Mean duration of follow-up was 18.6 (±12.1; range: 1.1-38.6) months. The cumulative success rate was 79% for SGDD and 88% for CPC at 1 year ( P =0.63). Although the study was underpowered, no significant differences in IOP, postoperative number of IOP-lowering medications, or adverse events were observed. The number of additional glaucoma surgeries ( P =0.003), office visits during the first 3 months ( P <0.001), and office visits per month after month 3 ( P <0.001) were greater in the SGDD group. CONCLUSIONS: Short-term overall success rates were high with either SGDD or CPC. However, SGDD was associated with more clinic visits and an increased risk of additional glaucoma surgery.

Using Anterior Segment Optical Coherence Tomography (ASOCT) Parameters to Determine Pupillary Block Versus Plateau Iris Configuration.

PRéCIS:: The potential parameters for differentiating pupillary block (PB) from plateau iris configuration (PIC) on anterior segment optical coherence tomography (ASOCT) are lens/pupil size parameters and angles. Further study is needed to determine a landmark peripheral to the centroid of the iris. PURPOSE: Investigate anterior segment parameters to distinguish between 2 mechanisms of angle closure, PB and PIC, using swept-source Fourier domain ASOCT. PATIENTS AND METHODS: Retrospective ASOCT images from narrow angle eyes were reviewed. PIC was defined either by ultrasound biomicroscopy and/or clinically when an iridoplasty was performed. Images were read by a masked reader using Anterior Chamber Analysis and Interpretation software to identify scleral spur landmarks and calculate anterior chamber, peripheral angle, iris size, iris shape, and lens/pupil size parameters. ASOCT parameters were summarized and compared using the 2-sample t test. Thresholds and area under receiver operating characteristic curve were calculated using logistic regression analysis. RESULTS: One hundred eyes (66 PB and 34 PIC) of 100 participants were reviewed. Of all ASOCT parameters, iris length in each quadrant, pupil arc, lens/pupil parameters (pupil arc, lens vault, and pupil diameter), all pupillary margin-center point-scleral spur landmark (PM-C-SSL) parameters, and all except superior central iris vault parameters were significantly different between PB and PIC. On threshold evaluation, lens/pupil parameters had the greatest area under receiver operating characteristic curve values (0.77 to 0.80), followed by PM-C-SSL angles (0.71 to 0.75). CONCLUSIONS: We propose that the pupil size parameters and PM-C-SSL angle are the most reliable novel ASOCT parameters to distinguish between PB and PIC eyes. These parameters do not rely on the visibility of the posterior iris surface, which is difficult to identify with ASOCT, but may be ambient lighting dependent.

New technology for examining the anterior segment by ultrasonic biomicroscopy.

PURPOSE: To compare the comfort levels and measurement accuracy of the open-shell technique and a bag/balloon technology (ClearScan, ESI) in anterior segment ultrasound biomicroscopy. SETTING: Department of Ophthalmology and Visual Science, Robert Cizik Eye Clinic, University of Texas Medical School at Houston, Houston, Texas, USA. METHODS: In this prospective investigation, 20 subjects stated their preference and rated comfort (0 best to 5 worst) for the open-shell technique versus the bag/balloon technology. Three anterior chamber depth and sulcus-to-sulcus measurements were obtained, and the mean for each structure was taken as datum for each subject. Order presentation between the 2 methods was randomized. Pairwise t tests and linear regression analysis were used to determine statistical differences. RESULTS: One hundred percent of the cohort preferred the bag/balloon technology to the traditional open-shell technique. The mean comfort score was 0.40 +/- 0.53 (SD) and 2.95 +/- 0.90, respectively (P<.0001). Anterior chamber depth measurements did not differ clinically (0.056 mm) nor did sulcus-to-sulcus determinations (0.039 mm). CONCLUSION: Biometry, patient comfort, and ease of use were better with the ClearScan bag/balloon technology than with the traditional open-shell technique.

Examiner Handedness and the Effects on Intraocular Pressure Readings Using the Tono-Pen XL.

PURPOSE: To assess the effect of examiner handedness on intraocular pressure (IOP) readings using the Tono-Pen XL in eyes without corneal pathology or previous ocular surgeries. PATIENTS AND METHODS: Patients 18 years of age or older were included in this prospective study. Participants who had a history of corneal conditions or other characteristics that would prevent reliable IOP measurements were excluded. Five experienced examiners, 2 right-hand dominant and 3 left-hand dominant, took bilateral IOP measurements with a Tono-Pen XL. Each participant was tested by 2 examiners, 1 left-handed and 1 right-handed, in a random order. The time between each examiner's measurements was 15 minutes. A paired t test was used to compare IOP differences between "near" (right eye for right-hand or left eye for left-hand dominant examiner) and "far" (right eye by left-hand or left eye by right-hand dominant examiner) measurements for each eye. RESULTS: Forty-six participants with a mean age of 33.8 years (±12.8) were enrolled. No significant difference in IOP between near and far eyes was found (IOP difference=IOPfar-IOPnear=-0.11 [±2.74] mm Hg; P=0.70). Right-hand dominant examiners consistently measured significantly higher IOP (0.83±2.03 mm Hg; P=0.008) compared with left-hand dominant examiners, regardless of the relative position of the eye with respect to the examiner. CONCLUSIONS: The results suggest that IOP readings are not influenced by the positioning of the patient relative to the dominant hand of the examiner.

Long-term Outcome of Argon Laser Peripheral Iridoplasty in the Management of Plateau Iris Syndrome Eyes.

PURPOSE: To report long-term (>5 y) outcomes of plateau iris syndrome patients treated with argon laser peripheral iridoplasty (ALPI). PATIENTS AND METHODS: A retrospective chart review was performed on all patients with plateau iris syndrome treated with ALPI from 1996 to 2007. The study included 22 eyes from 22 patients with plateau iris after peripheral iridotomy that were followed for at least 1 year after ALPI. The primary outcome was incidence of needing any intraocular pressure (IOP)-lowering medications or surgery (either a filtering procedure or phacoemulsification). Demographic and baseline clinical data were summarized by mean (±SD) or frequency (percentage). Snellen best-corrected visual acuity was converted to logMAR. The paired t test was used to compare IOP changes, number of IOP-lowering medications, and best-corrected visual acuity from baseline to annual follow-up. RESULTS: Mean follow-up was 76 months. Only 2 (9%) eyes maintained an IOP<21 mm Hg without requiring medication or surgery. Seventeen (77%) eyes underwent surgery at an average of 49.1±7.9 months after ALPI. Eight (36%) eyes underwent filtering surgery, and 9 (41%) eyes underwent phacoemulsification. Three months after cataract extraction, no eyes required IOP-lowering medication. CONCLUSIONS: The beneficial effects of ALPI last for <4 years, with the majority of patients (77%) requiring surgery. Phacoemulsification alone was a successful treatment for plateau iris in our patient population.

Surgical repair of large cyclodialysis clefts.

PURPOSE: To describe a new surgical technique to effectively close large (>180 degrees) cyclodialysis clefts. METHODS: Our method involves the use of procedures commonly associated with repair of retinal detachment and complex cataract extraction: phacoemulsification with placement of a capsular tension ring followed by pars plana vitrectomy and gas tamponade with light cryotherapy. We also used anterior segment optical coherence tomography (OCT) as a noninvasive mechanism to determine the extent of the clefts and compared those results with ultrasound biomicroscopy (UBM) and gonioscopy. RESULTS: This technique was used to repair large cyclodialysis clefts in 4 eyes. All 4 eyes had resolution of hypotony and improvement of visual acuity. One patient had an intraocular pressure spike requiring further surgical intervention. Anterior segment OCT imaging in all 4 patients showed a more extensive cleft than UBM or gonioscopy. CONCLUSIONS: This technique is effective in repairing large cyclodialysis clefts. Anterior segment OCT more accurately predicted the extent of each cleft, while UBM and gonioscopy both underestimated the size of the cleft.

Comparison of Efficacy and Complications of Cyclophotocoagulation and Second Glaucoma Drainage Device After Initial Glaucoma Drainage Device Failure.

PURPOSE: Compare intraocular pressure (IOP) control and complication rates of a second glaucoma drainage device (GDD) to diode transscleral cyclophotocoagulation (TSCPC) following failure of an initial GDD. PATIENTS AND METHODS: Eyes with 1 GDD that required a second GDD or TSCPC for glaucoma control were included. Exclusion criteria were a cyclodestructive procedure before initial GDD, no light perception vision, or follow-up <1 year. Failure was defined as ≥1 of (1) reoperation for lowering IOP; (2) explantation of second GDD; (3) persistent hypotony; (4) use of oral carbonic anhydrase inhibitor for lowering IOP in the study eye; or (5) loss of light perception. Reoperation for lowering IOP included additional GDD implantation or additional cyclodestruction, except if additional cyclodestruction was within 6 months of the initial session. RESULTS: A total of 75 eyes (35 in second GDD; 40 in TSCPC) were included (mean follow-up, 25.5 mo). Both procedures lowered IOP [-11.4 mm Hg (±13.6) for second GDD and -7.8 mm Hg (±11.8) for TSCPC groups] and decreased the number of IOP-lowering medications at the last visit. The second GDD group had significantly greater mean survival time [45.0 mo (±4.2)] than the TSCPC group [26.5 mo (±2.8)] but significantly more postoperative complications (60% of eyes) and non-IOP-related procedures (40% of eyes) than the TSCPC group (20% for postoperative complications and 18% for non-IOP-related procedures). CONCLUSIONS: Although both second procedures are efficacious in lowering IOP and number of IOP-lowering medications, TSCPC failed earlier, whereas a second GDD had significantly more complications.

Subretinal suture misdirection during 360 degrees suture trabeculotomy.

PURPOSE: To report a new complication of 360 degrees suture trabeculotomy attributable to subretinal suture misdirection. DESIGN: Observational case report. METHODS: Retrospective chart review. RESULTS: A 5-month-old female with bilateral congenital glaucoma underwent uncomplicated 360 degrees suture trabeculotomy in the right eye. In the left eye, a scleral flap was created and dissection to Schlemm's canal was achieved. A 6-0 Prolene suture was passed into Schlemm's canal long enough for 360 degrees of treatment, did not come out the opening, and was retracted. The procedure was completed with a trabeculotome. One month later, an unusual white tract was noted subretinally in the left eye. There was no overlying retinal break or detachment. The tract presumably was caused by the misdirected Prolene suture exiting Schlemm's canal prematurely and being directed posteriorly. CONCLUSIONS: Suture misdirection subretinally during cannulation of Schlemm's canal should be considered a possible complication of 360 degrees suture trabeculotomy.

Intraoperative management of nonfunctioning Ahmed glaucoma valve implant.

A 62-year-old woman with neovascular glaucoma underwent filtering surgery with the Ahmed glaucoma valve (New World Medical, Inc., Rancho Cucamonga, CA). Intraoperative hypotony secondary to a defective valve was noted and managed by excising the valve mechanism. The implant was then treated as if it was non-valved by placement of an obturator suture. The postoperative course was unremarkable for a non-valved implant. This case demonstrates how intraoperative hypotony secondary to overfiltration of an Ahmed glaucoma valve implant can be successfully managed by converting to a non-valved implant.

Agreement between Gonioscopic Examination and Swept Source Fourier Domain Anterior Segment Optical Coherence Tomography Imaging.

Purpose. To evaluate interobserver, intervisit, and interinstrument agreements for gonioscopy and Fourier domain anterior segment optical coherence tomography (FD ASOCT) for classifying open and narrow angle eyes. Methods. Eighty-six eyes with open or narrow anterior chamber angles were included. The superior angle was classified open or narrow by 2 of 5 glaucoma specialists using gonioscopy and imaged by FD ASOCT in the dark. The superior angle of each FD ASOCT image was graded as open or narrow by 2 masked readers. The same procedures were repeated within 6 months. Kappas for interobserver and intervisit agreements for each instrument and interinstrument agreements were calculated. Results. The mean age was 50.9 (±18.4) years. Interobserver agreements were moderate to good for both gonioscopy (0.57 and 0.69) and FD ASOCT (0.58 and 0.75). Intervisit agreements were moderate to excellent for both gonioscopy (0.53 to 0.86) and FD ASOCT (0.57 and 0.85). Interinstrument agreements were fair to good (0.34 to 0.63), with FD ASOCT classifying more angles as narrow than gonioscopy. Conclusions. Both gonioscopy and FD ASOCT examiners were internally consistent with similar interobserver and intervisit agreements for angle classification. Agreement between instruments was fair to good, with FD ASOCT classifying more angles as narrow than gonioscopy.

Establishing Age-Adjusted Reference Ranges for Iris-Related Parameters in Open Angle Eyes with Anterior Segment Optical Coherence Tomography.

PURPOSE: Define criteria for iris-related parameters in an adult open angle population as measured with swept source Fourier domain anterior segment optical coherence tomography (ASOCT). METHODS: Ninety-eight eyes of 98 participants with open angles were included and stratified into 5 age groups (18-35, 36-45, 46-55, 56-65, and 66-79 years). ASOCT scans with 3D mode angle analysis were taken with the CASIA SS-1000 (Tomey Corporation, Nagoya, Japan) and analyzed using the Anterior Chamber Analysis and Interpretation software. Anterior iris surface length (AISL), length of scleral spur landmark (SSL) to pupillary margin (SSL-to-PM), iris contour ratio (ICR = AISL/SSL-to-PM), pupil radius, radius of iris centroid (RICe), and iris volume were measured. Outcome variables were summarized for all eyes and age groups, and mean values among age groups were compared using one-way analysis of variance. Stepwise regression analysis was used to investigate demographic and ocular characteristic factors that affected each iris-related parameter. RESULTS: Mean (±SD) values were 2.24 mm (±0.46), 4.06 mm (±0.27), 3.65 mm (±0.48), 4.16 mm (±0.47), 1.14 (±0.04), 1.51 mm2 (±0.23), and 38.42 µL (±4.91) for pupillary radius, RICe, SSL-to-PM, AISL, ICR, iris cross-sectional area, and iris volume, respectively. Both pupillary radius (P = 0.002) and RICe (P = 0.027) decreased with age, while SSL-to-PM (P = 0.002) and AISL increased with age (P = 0.001). ICR (P = 0.54) and iris volume (P = 0.49) were not affected by age. CONCLUSION: This study establishes reference values for iris-related parameters in an adult open angle population, which will be useful for future studies examining the role of iris changes in pathologic states.

Determination and Validation of Thresholds of Anterior Chamber Parameters by Dedicated Anterior Segment Optical Coherence Tomography.

PURPOSE: To determine and validate thresholds of anterior chamber angle (ACA) parameters in discriminating open- vs narrow-angle eyes using images from dedicated anterior segment optical coherence tomography (DASOCT). DESIGN: Reliability analysis. METHODS: Eyes imaged by DASOCT and examined with gonioscopy were reviewed. By gonioscopy, eyes were classified as narrow if posterior trabecular meshwork was not visible and open if the angle was open to scleral spur and beyond. Imaging was performed in the dark with the CASIA SS-1000 (Tomey, Nagoya, Japan). ACA parameters angle opening distance (AOD), trabecular-iris space area (TISA), trabecular-iris circumference volume (TICV), length of iridotrabecular contact (ITC), and extent and area of ITC were calculated. AOD, TISA, and TICV were measured at both 500 µm and 750 µm from the scleral spur landmark. Study eyes were randomly divided into training and testing sets. Thresholds were calculated from the training set. Sensitivity, specificity, and agreement were then calculated against the clinical classification using the testing set. RESULTS: One hundred and eighty-nine eyes (111 open, 78 narrow, including 8 borderline angles) were included. Using the threshold determined in the training set on the testing set, 9 of 24 ACA parameters had no misclassification of narrow-angle eyes as open (sensitivity = 1.0). Of 9 parameters, the specificity was >0.79. The highest kappa values (kappa = 0.91) was AOD750 inferiorly at 0.31 mm threshold, followed by both TICV500 at 1.92 µL and TICV750 at 4.00 µL with kappa = 0.86. CONCLUSION: The parameters with the best discriminative ability for detecting narrow angles were AOD750 inferiorly, TICV500, and TICV750.

Comparing Laser Peripheral Iridotomy to Cataract Extraction in Narrow Angle Eyes Using Anterior Segment Optical Coherence Tomography.

PURPOSE: To evaluate the changes in anterior chamber angle (ACA) parameters in primary angle closure (PAC) spectrum eyes before and after cataract extraction (CE) and compare to the changes after laser peripheral iridotomy (LPI) using anterior segment optical coherence tomography (ASOCT). METHODS: Twenty-eight PAC spectrum eyes of 18 participants who underwent CE and 34 PAC spectrum eyes of 21 participants who underwent LPI were included. ASOCT images with 3-dimensional mode angle analysis scans were taken with the CASIA SS-1000 (Tomey Corp., Nagoya, Japan) before and after CE or LPI. Mixed-effect model analysis was used to 1) compare best-corrected visual acuity, intraocular pressure, and ACA parameters before and after CE; 2) identify and estimate the effects of potential contributing factors affecting changes in ACA parameters; and 3) compare CE and LPI treatment groups. RESULTS: The increase in average angle parameters (TISA750 and TICV750) was significantly greater after CE than LPI. TICV750 increased by 102% (2.114 [±1.203] µL) after LPI and by 174% (4.546 [± 1.582] µL) after CE (P < 0.001). Change of TICV750 in the CE group was significantly affected by age (P = 0.002), race (P = 0.006), and intraocular lens power (P = 0.037). CONCLUSIONS: CE results in greater anatomic changes in the ACA than LPI in PAC spectrum eyes. ASOCT may be used to follow anatomic changes in the angle after intervention.

Effect of Laser Peripheral Iridotomy on Anterior Chamber Angle Anatomy in Primary Angle Closure Spectrum Eyes.

PURPOSE: To evaluate the change in trabecular-iris circumference volume (TICV) after laser peripheral iridotomy (LPI) in primary angle closure (PAC) spectrum eyes. PATIENTS AND METHODS: Forty-two chronic PAC spectrum eyes from 24 patients were enrolled. Eyes with anterior chamber abnormalities affecting angle measurement were excluded. Intraocular pressure, slit lamp examination, and gonioscopy were recorded at each visit. Anterior segment optical coherence tomography (ASOCT) with 3D mode angle analysis scans were taken with the CASIA SS-1000 before and after LPI. Forty-two pre-LPI ASOCT scans and 34 post-LPI ASOCT scans were analyzed using the Anterior Chamber Analysis and Interpretation (ACAI) software. A mixed-effect model analysis was used to compare the trabecular-iris space area (TISA) changes among 4 quadrants, as well as to identify potential factors affecting TICV. RESULTS: There was a significant increase in all average angle parameters after LPI (TISA500, TISA750, TICV500, and TICV750). The magnitude of change in TISA500 in the superior angle was significantly less than the other angles. The changes in TICV500 and TICV750 were not associated with any demographic or ocular characteristics. CONCLUSIONS: TICV is a useful parameter to quantitatively measure the effectiveness of LPI in the treatment of eyes with PAC spectrum disease.

Optimal number of angle images for calculating anterior angle volume and iris volume measurements.

PURPOSE: We determined the optimal number of angle images required to obtain reliable measurements of trabecular-iris circumferential volume (TICV) and iris volume (IV) using swept-source Fourier domain anterior segment optical coherence tomography (SSFD-ASOCT) scans in narrow angle eyes. METHODS: Scleral spur landmarks (SSL) were manually identified on ASOCT angle images from 128 meridians from each of 24 eyes with chronic primary angle closure (PAC) spectrum of disease. The anterior and posterior corneal curves, and the anterior and posterior iris surfaces were identified automatically by the anterior chamber analysis and interpretation (ACAI) software, then manually examined and edited by the reader if required. Trabecular-iris circumferential volume at 750 µm from SSL (TICV750) and IV were subsequently calculated using varying numbers of angle images. Threshold error was determined to be less than the lower 95% confidence limit of mean absolute percent error (MAPE) of the change in TICV or IV resulting from laser peripheral iridotomy, which would be 17% for TICV and 5% for IV, based on previous studies. The optimal number of angle images was the smallest number of images where MAPE was less than this threshold for TICV and IV. RESULTS: A total of 32 equally-spaced angle images (16 meridians) was required to estimate TICV750 and 16 angle images (8 meridians) to estimate IV. Both were within 4.6% and 1.6% of MAPE, respectively. CONCLUSIONS: It is possible to determine TICV and IV parameters reliably in narrow angles without evaluating all 128 meridians obtained with SSFD-ASOCT.

Correlation between intraocular pressure and body mass index in the seated and supine positions.

PURPOSE: Examine the relationship between intraocular pressure (IOP) and body mass index (BMI) in the seated and supine positions. PATIENTS AND METHODS: A prospective observational study was conducted in which the IOP was measured with a Tono-Pen (Reichert Inc., Depew, NY) in seated and supine positions in eligible participants with a wide range of BMI (18 to 70 kg/m). The paired t test was used to compare seated to supine IOP. Stepwise regression analyses were used to investigate the correlation between IOP and BMI at these positions after adjusting for confounding variables of increased IOP, including age, race, mean arterial blood pressure, and central corneal thickness (µm). RESULTS: The mean sitting IOP (16.3±2.9 mm Hg) was statistically lower than the mean supine IOP (17.7±3.1 mm Hg; P<0.0001). For each 10 unit increase in BMI, there was an increase of 0.55±0.23 mm Hg (P=0.0184) in IOP in the seated position and an increase of 0.49±0.24 mm Hg in IOP in the supine position (P=0.0409). BMI did not have a significant effect on the amount of increase in IOP observed in changing from the seated to supine position. CONCLUSIONS: Higher BMI is correlated with higher IOP in both the seated and supine positions. However, BMI has no significant effect on the amount of increase in IOP observed in changing from the seated to supine position.