Evaluation of the Anterior Chamber Angle in Glaucoma

Anterior chamber and angle characteristics in Chinese children (6-11 years old) with different refractive status using swept-source optical coherence tomography

BACKGROUND

The anatomic structure of the anterior chamber (AC) helps to explain differences in refractive status in school-aged children and is closely associated with primary angle closure (PAC). The aim of this study was to quantify and analyze the anterior chamber and angle (ACA) characteristics in Chinese children with different refractive status by swept-source optical coherence tomography (SS-OCT).

METHODS

In a cross-sectional observational study, 383 children from two primary schools in Shandong Province, China, underwent a complete ophthalmic examination. First, the anterior chamber depth (ACD), anterior chamber width (ACW), angle-opening distance (AOD), and trabecular-iris space area (TISA) were evaluated automatically using a CASIA2 imaging device. AOD and TISA were measured at 500, 750 μm nasal (N1 and N2, respectively), and temporal (T1 and T2, respectively) to the scleral spur (SS). Cycloplegic refraction and axial length (AL) were then measured. According to spherical equivalent refraction (SER), the children were assigned to hyperopic (SER > 0.50D), emmetropic (-0.50D < SER ≤ 0.50D), and myopic groups (SER ≤ -0.50D).

RESULTS

Out of the 383 children, 349 healthy children (160 girls) with a mean age of 8.23 ± 1.06 years (range: 6-11 years) were included. The mean SER and AL were - 0.10 ± 1.57D and 23.44 ± 0.95 mm, respectively. The mean ACD and ACW were 3.17 ± 0.24 mm and 11.69 ± 0.43 mm. The mean AOD were 0.72 ± 0.25, 0.63 ± 0.22 mm at N1, T1, and 0.98 ± 0.30, 0.84 ± 0.27 mm at N2, T2. The mean TISA were 0.24 ± 0.09, 0.22 ± 0.09mm2 at N1, T1, and 0.46 ± 0.16, 0.40 ± 0.14mm2 at N2, T2. The myopic group had the deepest AC and the widest angle. Compared with boys, girls had shorter AL, shallower ACD, narrower ACW, and ACA (all p < 0.05). By Pearson's correlation analysis, SER was negatively associated with ACD, AOD, and TISA. AL was positively associated with ACD, ACW, AOD, and TISA. In the multiple regression analysis, AOD and TISA were associated with deeper ACD, narrower ACW, and longer AL.

CONCLUSION

In primary school students, the myopic eyes have deeper AC and wider angle. ACD, ACW, AOD, and TISA all increase with axial elongation. ACA is highly correlated with deeper ACD.

Anterior Segment Changes in Patients With Glaucoma Following Cataract Surgery

This prospective observational study investigates the impact of cataract surgery on anterior segment parameters in nonglaucomatous and primary open-angle glaucoma (POAG) eyes, utilizing anterior segment optical coherence tomography (AS-OCT). The study involved 42 Caucasian patients, divided into a control group and a POAG group. Comprehensive ophthalmic examinations were performed along with AS-OCT imaging and biometry preoperatively, as well as on one day, one week, and one month following cataract surgery. The results showed significant post-operative changes in anterior chamber depth (ACD) and angle width in both groups, suggesting that cataract surgery may influence the structural parameters associated with glaucoma risk and management. Specifically, a marked increase in ACD and improvement in angle-opening distances were observed, highlighting the potential of cataract extraction to alter intraocular fluid dynamics favorably. Despite these changes, the study noted an initial spike in increased intraocular pressure (IOP) in POAG patients immediately post-operative, which stabilized during follow-up. For the control group, IOP showed gradually reducing IOP values in the follow-up visits. The findings underscore the role of advanced imaging technologies in understanding glaucoma's pathophysiology and the potential benefits of cataract surgery in glaucoma patients. The study advocates for further research with a larger, more diverse patient population and extended follow-up to explore the long-term implications of cataract surgery on glaucoma dynamics, emphasizing the importance of personalized management and treatment strategies particularly for glaucoma patients.

The Finnish current care guideline for open-angle glaucoma

This article is an English translation of the 4th Finnish Current Care Guideline for diagnostics, treatment and follow-up of primary open-angle glaucoma, normal-tension glaucoma and pseudoexfoliative glaucoma. This guideline is based on systematic literature reviews and expert opinions with Finland's geographical and operational healthcare environment in mind.

Progress in the Application of Microneedles in Eye Disorders and the Proposal of the Upgraded Microneedle with Spinule

PURPOSE

In the local administration methods for treating eye diseases, the application of microneedles has great potential due to the shortcomings of low efficacy and significant side effects of local administration preparations. This article provides ideas for the research on the application of ophthalmic microneedle in the treatment of eye diseases.

RESULTS

This article analyzes the physiological structures of the eyes, ocular diseases and its existing ocular preparations in sequence. Finally, this article reviews the development and trends of ocular microneedles in recent years, and summarizes and discusses the drugs of ocular microneedles as well as the future directions of development. At the same time, according to the inspiration of previous work, the concept of "microneedle with spinule" is proposed for the first time, and its advantages and limitations are discussed in the article.

CONCLUSIONS

At present, the application of ocular microneedles still faces multiple challenges. The aspects of auxiliary devices, appearance, the properties of the matrix materials, and preparation technology of ophthalmic microneedle are crucial for their application in the treatment of eye diseases.

Role of Static and Dynamic Ocular Biometrics Measured in the Dark and Light as Risk Factors for Angle Closure Progression

PURPOSE

To assess the role of static and dynamic ocular biometric parameters measured in the dark and light for predicting progression of primary angle closure suspect (PACS) to primary angle closure (PAC).

DESIGN

Retrospective cohort study using prospective randomized controlled trial data from untreated, control eyes.

METHODS

Zhongshan Angle Closure Prevention Trial subjects underwent anterior segment optical coherence tomography (AS-OCT) imaging in the dark and light. Static biometric parameters were measured, consisting of angle, iris, lens, and anterior chamber parameters. Dynamic change parameters were calculated by subtracting light measurements from dark measurements. Cox proportional hazards regression models were developed to assess risk factors for PACD progression.

RESULTS

A total of 861 eyes of 861 participants were analyzed (36 progressors). On univariable analysis, TISA500 measurements in the light and dark were associated with progression (P < .001), whereas dynamic change parameters were not (P ≥ .08). In the primary multivariable model, older age (hazard ratio [HR] = 1.09 per year), higher intraocular pressure (IOP) (HR = 1.13 per mm Hg), and smaller TISA500 in the light (HR = 1.28 per 0.01 mm2) were significantly associated with greater risk of progression (P ≤ .04). Dark TISA500 had similar significance (HR = 1.28, P = .002) when replacing light TISA500. Risk of progression was more predictive among eyes in the lowest quartile of light TISA500 measurements (HR = 4.56, P < .001) compared to dark measurements (HR = 2.89, P = .003).

CONCLUSION

Static parameters measured in the light are as predictive, and possibly more so, of angle closure progression as those measured in the dark. Ocular biometrics measured under light and dark conditions may provide additional information for risk-stratifying patients for angle closure progression.

Profiling and factors associated with glaucoma diagnostic practice in sub-Saharan Africa-a cross sectional study of Nigerian and Ghanaian optometrists

BACKGROUND

Ghana and Nigeria are the two countries in Africa that currently run the Doctor of Optometry (OD) program in sub-Saharan Africa (SSA). Optometrists in these countries are licensed to provide glaucoma care. Despite the clinically relevant practice guidelines for glaucoma, there is no data on the practice patterns for glaucoma eye care in SSA, a region with the highest prevalence of glaucoma. This study aimed to profile glaucoma diagnosis adherence to practice guidelines among optometrists in two neighbouring anglophone countries (Nigeria and Ghana).

METHODS

A web-based cross-sectional survey of practising optometrists was conducted in both countries. Each country data was weighted to reflect the total number of licensed and practising optometrists at the time of this survey. Descriptive analyses were performed against demography and practice factors using survey commands to adjust for sampling weights when estimating confidence intervals (CI) around prevalence estimates. Simple and multiple logistic regression analyses were performed to identify factors associated with glaucoma diagnosis.

RESULTS

A total of 493 optometrists (238, 48.3% and 255, 51.7%) from Ghana and Nigeria respectively, responded to the survey-the first to document and compare the glaucoma diagnostic criteria between optometrists in Ghana and Nigeria. More Ghanaian than Nigerian optometrists diagnosed glaucoma and over 90% in both countries reported that they frequently performed either tonometry, visual field testing, or fundus examination during glaucoma diagnosis. Ghanaian optometrists were significantly more likely to diagnose glaucoma than Nigerian optometrists (adjusted odd ratio, AOR = 6.15, 95%CI:1.63-23.15, P = .007). Optometrists who have practiced for more than 10 years (AOR = 7.04; 95%CI:1.74-28.47, P = .006) and private practice optometrists (AOR = 3.33; 95%CI:1.13-9.83, P = .03) were more likely to diagnose glaucoma.

CONCLUSIONS

The study provides information for evaluating glaucoma assessment for optometrists in both countries. Optometrists in both countries are reasonably well-equipped to diagnose glaucoma and are practicing at an adequate level, but with room for improvement.

Characteristics of the Ciliary Body in Healthy Chinese Subjects Evaluated by Radial and Transverse Imaging of Ultrasound Biometric Microscopy

Background: The imaging and analysis of the ciliary body (CB) are valuable in many potential clinical applications. This study aims to demonstrate the anatomy characteristics of CB using radial and transverse imaging of ultrasound biometric microscopy (UBM) in healthy Chinese subjects, and to explore the determining factors. Methods: Fifty-four eyes of 30 healthy Chinese subjects were evaluated. Clinical data, including age, body mass index (BMI), intraocular pressure (IOP), axial length (AL), and lens thickness (LT), were collected. Radial and transverse UBM measurements of the ciliary body were performed. Anterior chamber depth (ACD), ciliary sulcus diameter (CSD), ciliary process length (CPL), ciliary process density (CPD), ciliary process area (CPA), ciliary muscle area (CMA), ciliary body area (CBA), ciliary body thickness (CBT0, CBT1, and CBTmax), anterior placement of ciliary body (APCB), and trabecular-ciliary angle (TCA) of four (superior, nasal, inferior, and temporal) quadrants were measured. Results: The average CPL was 0.513 ± 0.074 mm, and the average CPA was 0.890 ± 0.141 mm2. CPL and CPA tended to be longer and larger in the superior quadrant (p < 0.001) than in the other three quadrants. Average CPL was significantly correlated with AL (r = 0.535, p < 0.001), ACD (r = 0.511, p < 0.001), and LT (r = −0.512, p < 0.001). Intraclass correlation coefficient (ICC) scores were high for CPL (0.979), CPD (0.992), CPA (0.966), CMA (0.963), and CBA (0.951). Conclusions: In healthy Chinese subjects, CPL was greatest in the superior quadrant, followed by the inferior, temporal, and nasal quadrants, and CPA was largest in the superior quadrant, followed by the tempdoral, inferior, and nasal quadrants. Transverse UBM images can be used to measure the anatomy of the ciliary process with relatively good repeatability and reliability.

Potentially Missed Opportunities in Prevention of Acute Angle-Closure Crisis

Importance

If an anatomic narrow angle is not appropriately diagnosed and treated, it can result in acute angle-closure crisis (AACC) and lead to substantial vision loss.

Objective

To identify patients who presented with AACC and assess for factors that may have been associated with risk of developing it.

Design, Setting, and Participants

This population-based retrospective cohort study conducted from January 1, 2001, to December 31, 2015, included a 20% nationwide sample of 1179 Medicare beneficiaries. Patients aged 40 years or older with AACC were identified with billing codes. A 2-year lookback period from the date of initial presentation of AACC was used to identify patients who had at least 1 eye care visit, received a diagnosis of open-angle glaucoma (OAG) or suspected OAG, or received at least 1 medication associated with risk of AACC. Of the patients who had at least 1 eye care visit, those who underwent gonioscopy, received a diagnosis of an anatomic narrow angle before developing AACC, or both were identified.

Main Outcomes and Measures

Proportions of patients who had at least 1 eye care visit, had OAG or suspected OAG, received at least 1 medication associated with risk of AACC, underwent gonioscopy, or received a diagnosis of an anatomic narrow angle before development of AACC.

Results

A total of 1179 patients had a confirmed diagnosis of AACC. The mean (SD) age of patients with AACC was 66.7 (11.8) years (range, 40-96 years), 766 were women (65.0%), 57 were Asian (4.8%), 109 were Black (9.2%), 126 were Latino (10.7%), 791 were White (67.1%), and 96 were other race and ethnicity (8.1%). Of these patients, only 796 (67.5%) consulted an optometrist or ophthalmologist at least once during the 2-year lookback period. A total of 464 individuals (39.4%) had OAG or suspected OAG, and 414 (35.1%) had received at least 1 medication associated with increased risk of AACC before developing it. Of the 796 patients who consulted an optometrist or ophthalmologist in the lookback period, less than one-third underwent gonioscopy in the 2 years before developing AACC (n = 264 [33.2%]), and less than one-half of all patients undergoing gonioscopy received a diagnosis of an anatomic narrow angle (n = 113 [42.8%]). Most patients underwent gonioscopy in the 1 to 4 weeks preceding the AACC.

Conclusions and Relevance

In this group of Medicare patients, there appear to have been multiple opportunities for interventions that may have averted AACC. Interventions aimed at addressing risk factors associated with AACC and improving performance of gonioscopy might be associated with reduced risk for ocular morbidity.

Diagnostic Performance of Optical Coherence Tomography and Nonspecialist Gonioscopy to Detect Angle Closure

Aim

To compare the usefulness of gonioscopy performed by general ophthalmologists (GO) and anterior segment optical coherence tomography (AS-OCT) in detecting angle closure in patients with a shallow anterior chamber.

Methods

Forty-four patients with a shallow anterior chamber (defined by a ratio of peripheral anterior chamber depth to peripheral corneal thickness lower than 1/2) were included in this cross-sectional study. Gonioscopy was performed in all subjects by two glaucoma experts (GE1 and GE2) and one GO. Anterior segment imaging was performed using Visante® OCT (Carl Zeiss Meditec Inc.). Agreement between examiners was assessed with first-order agreement coefficients (AC1). Diagnostic accuracies of GO gonioscopy and AS-OCT were evaluated using sensitivity, specificity, and area under the receiver operating characteristic (AROC) curves.

Results

For static gonioscopy, the agreement between GE1 and GE2 was substantial (AC1 = 0.65), and that between GE1 and GO was moderate (AC1 = 0.50). For indentation gonioscopy, the agreement between GE1 and GE2 was slightly lower (AC1 = 0.55); however, the agreement between GE1 and GO showed a larger reduction (AC1 = 0.12). GO's gonioscopy presented a low specificity (25%) and the AROC to angle closure detection was lower than AS-OCT (0.56–0.73). Combined information of GO gonioscopy and AS-OCT improved specificity (85.7%) and AROC (0.77) of angle closure evaluation.

Conclusion

Agreement between GO and glaucoma experts was moderate for static gonioscopy and slight for indentation gonioscopy. AS-OCT performed better than GO gonioscopy in detecting angle closure in patients with a shallow anterior chamber. The addition of AS-OCT to clinical information in patients with GO positive gonioscopy improved the specificity and AROC of gonioscopy test.

How to cite this article

Esporcatte BLB, Vessani RM, Melo Jr LAS, et al. Diagnostic Performance of Optical Coherence Tomography and Nonspecialist Gonioscopy to Detect Angle Closure. J Curr Glaucoma Pract 2022;16(1):53–58.

Pupillary Dilation in Research: More than Meets the Eye

Purpose: Pupil dilation is a commonly used procedure in vision research. While often considered a minimal risk procedure, there is the potential for significant adverse effects. Methods: Currently, there is variance in practices and protocols among researchers and institutions, perhaps due to a lack of guidelines for safe pupil dilation practices in research settings. In this perspective, we explore variables that can increase the potential for adverse effects and provide suggestions to limit their impact. Prior to dilation, an investigator can assess an individual's medical status and drug regimen when deciding upon a mydriatic agent to be used. Results: Assessing the angle through a variety of methods (i.e. penlight test, van Herick slit lamp, optical coherence tomography, gonioscopy) can also prevent inappropriate dilation of pupils with concerning anatomical features. During dilation, an investigator should look to limit the potential of infection and use caution in repeat dosing of dilation-resistant pupils. Conclusions: Post-dilation, an investigator should closely monitor eyes with elevated risk factors and improve an individual's health literacy on angle closure complications. When combined with proper informed consent processes regarding adverse effects, the aforementioned can allow for risk mitigation in studies using pupil dilation.

Ocular Biometric Determinants of Dark-to-Light Change in Angle Width: The Chinese American Eye Study

PURPOSE

To assess ocular biometric determinants of dark-to-light change in anterior chamber angle width and identify dynamic risk factors in primary angle closure disease (PACD).

DESIGN

Population-based cross-sectional study.

METHODS

Chinese American Eye Study (CHES) participants underwent anterior segment optical coherence tomography imaging in the dark and light. Static dark and light biometric parameters, including angle opening distance, 750 µm (AOD750), anterior chamber width (ACW), lens vault (LV), and pupillary diameter (PD) were measured, and dynamic dark-to-light changes were calculated. Contributions by static and dynamic parameters to dark-to-light changes in AOD750 were assessed using multivariable linear regression models with standardized regression coefficients (SRCs) and semipartial correlation coefficients squared (SPCC²). PACD was defined as ≥3 quadrants of gonioscopic angle closure.

RESULTS

The analysis included 1011 participants. All biometric parameters differed between dark and light (P < .05). On multivariable regression analysis, change in ACW (SRC = -0.35, SPCC² = 0.081) and PD (SRC = -0.46, SPCC² = 0.072) were the strongest determinants of dark-to-light change in AOD750 (overall R² = 0.40). Dark-to-light increase in AOD750 was less in eyes with than without PACD (0.081 mm and 0.111 mm, respectively; P < .001). ACW increased in eyes with PACD and decreased in eyes without PACD from dark to light (P < .025), whereas change in PD was similar (P = .28).

CONCLUSIONS

Beneficial angle widening effects of transitioning from dark to light are attenuated in eyes with PACD, which appears related to aberrant dark-to-light change in ACW. These findings highlight the importance of assessing the angle in both dark and light to identify potential dynamic mechanisms of angle closure.

Comparison of Iridocorneal Angle Assessments in Open-Angle Glaucoma and Ocular Hypertension Patients: Anterior Segment Optical Coherence Tomography and Gonioscopy

Purpose

To quantitatively compare iridocorneal angle assessments using gonioscopy and anterior segment optical coherence tomography (AS-OCT).

Patients

US and Chinese patients with open-angle glaucoma (OAG) and/or ocular hypertension (OHT).

Methods

Analysis was pooled from 2 multicenter, noninterventional studies conducted in the US and China. Gonioscopy Shaffer grade and an AS-OCT method that approximates the angle width relative to local morphologic variations were compared by measuring the same iridocorneal angles. A third, separate, single-center, noninterventional study was conducted to verify results observed from the pooled analysis.

Results

From the pooled studies, a total of 239 eyes were measured using Shaffer grade and AS-OCT. Of these, 6 were Shaffer grade 2, 37 in Shaffer grade 3, and 196 in Shaffer grade 4. There was a trend of increasing Shaffer grade with increasing AS-OCT angle width. Open iridocorneal angles, Shaffer grade ≥3, had a ~98% sensitivity and 88% positive predictive value for identifying AS-OCT angle width ≥300 µm, using the AS-OCT method. To verify these results, a total of 28 right eyes were imaged for the third study. A trend of increasing Shaffer grade with increasing AS-OCT angle width was observed, and angles with Shaffer grade ≤2 had AS-OCT angle width <300 µm.

Conclusion

The AS-OCT method can determine the space in the anterior chamber and can potentially identify angles that are the appropriate size for certain glaucoma devices. Information gathered from AS-OCT can provide additional comprehensive and quantitative assessment to gonioscopy.

Anterior Chamber Angle Changes in Primary Angle-closure Glaucoma Following Phacoemulsification Versus Phacotrabeculectomy: A Prospective Randomized Clinical Trial

PRCIS

We used anterior segment optical coherence tomography to investigate anterior chamber angle in primary angle-closure glaucoma (PACG) eyes following phacoemulsification and phacotrabeculectomy. Angle widening was significantly greater after phacoemulsification up to 6 months after the surgery.

PURPOSE

To compare anterior chamber angle following 2 common surgeries for PACG.

METHODS

One hundred ten glaucoma patients were evaluated in this single center, prospective, randomized clinical trial. Those with concomitant PACG and senile cataract and without a history of ocular surgery, trauma, or chronic miotic use were recruited. Monocular patients were also excluded. Finally, 52 eligible subjects were randomly assigned to phacoemulsification ("Phaco" group, 25 eyes) or phacotrabeculectomy ("Combined" group, 27 eyes) surgeries. A swept-source, anterior segment optical coherence tomography device (CASIA SS-1000 OCT) was used to image the anterior segment. Mask graders used the images to measure the following parameters before and 1 week, 1 month, and 6 months after surgery: angle opening distance at 500 µm, trabecular iris surface area at 500 µm, and trabecular iris angle at 500 µm.

RESULTS

There was no significant difference between study groups regarding best-corrected visual acuity, intraocular pressure (IOP), and the number of glaucoma medications in preoperative or postoperative visits (P>0.076). Also, the measured angle parameters were not statistically significantly different between the 2 groups before surgery (P>0.123). After surgery, all measured parameters were significantly increased in both groups (P<0.0001). At the 6-month follow-up, nasal angle opening distance at 500 µm was 0.383±0.027 vs. 0.349±0.017, trabecular iris surface area at 500 µm was 0.141±0.007 vs. 0.125±0.005, and trabecular iris angle at 500 µm was 40.1±12.9 vs. 34.6±3.1 in Phaco and Combined groups, respectively (P<0.0001 for all).

CONCLUSIONS

Anterior chamber angle widening by anterior segment optical coherence tomography was observed in PACG patients following surgery and was significantly greater after phacoemulsification compared with combined phacotrabeculectomy at all time points. Similar IOP and medication burden were noted for up to 6 months as secondary outcomes. The contribution of angle changes to the IOP-lowering effect of phacoemulsification in PACG eyes needs further study.

Anterior Chamber Angle in Adults Born Extremely, Very, and Moderately Preterm with and without Retinopathy of Prematurity-Results of the Gutenberg Prematurity Eye Study

Purpose: To determine whether prematurity and associated factors affect the anterior chamber angle (ACA) width in adulthood. Methods: The Gutenberg Prematurity Eye Study (GPES) is a retrospective cohort study with a prospective ophthalmologic examination of adults (age 18–52 years) in Germany. All participants were examined with Scheimpflug imaging (Pentacam HR, Oculus Optikgeräte GmbH, Wetzlar, Germany) using linear regression analysis to assess the associations of ACA in the different sectors with gestational age (GA), birth weight, birth weight percentile, retinopathy of prematurity (ROP), ROP treatment, placental insufficiency, preeclampsia, and breastfeeding. Results: In total, 516 eyes of 319 preterm and full-term individuals (aged 28.9 ± 8.8 years, 188 females) were examined. ROP treatment was associated with smaller ACA width in the nasal (B = −9.6 [95%CI: −14.7; −4.5] degree; p < 0.001) and temporal positions (B = −11.5 [95%CI: −17.7; −5.3] degree; p = 0.001), whereas non-treated individuals with ROP had an unaltered ACA width, as did individuals with low gestational age without ROP. Conclusion: Advanced stages of ROP following treatment with laser- and cryocoagulation lead to a smaller ACA width until adulthood, and hence may increase the risk of angle closure in later life.

Detection of occludable angle with anterior segment optical coherence tomography and Pentacam as non-contact screening methods

Purpose

To evaluate diagnostic capacity for occludable anterior chamber angle detection with anterior segment optical coherence tomography (AS-OCT) and Pentacam.

Methods

Observational cross-sectional study with AS-OCT and Pentacam. AS-OCT measures: angle opening distance from Schwalbe line (SL) perpendicular (AOD-SL-Perp) and vertical to iris (AOD-SL-Vert), and iridotrabecular angle (ITA). Pentacam measures: anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA). We analysed Spearman’s correlation with gonioscopic classification. Area under receiver operating characteristic curves (AUCs) for occludable angle detection were compared. Agreement between iridocorneal values of methods was evaluated.

Results

Seventy-four left eyes of 74 patients. Correlation between temporal AS-OCT and gonioscopy: 0.83 (p < 0.0001) AOD-SL-Perp temporal, 0.82 (p < 0.0001) AOD-SL-Vert temporal, and 0.69 (p < 0.0001) ITA temporal. Correlation between AS-OCT nasal and gonioscopy: 0.74 (p < 0.0001) AOD-SL-Perp nasal, 0.74 (p < 0.0001) AOD-SL-Vert nasal, and 0.70 (p < 0.0001) ITA nasal. Correlation of Pentacam with temporal gonioscopy: 0.57 (p < 0.0001) ACD, 0.56 (p < 0.0001) ACV, and 0.63 (p < 0.0001) ACA. Correlation of Pentacam with nasal gonioscopy: 0.47 (IC 0.27–0.73, p < 0.0001) ACD, 0.49 (p < 0.0001) ACV, and 0.56 (CI 0.38–0.7, p < 0.0001) ACA. AS-OCT AUCs: AOD-SL-Perp temporal 0.89 (CI 0.80–0.95), AOD-SL-Vert 0.87 (CI 0.77–0.94), ITA temporal 0.88 (CI 0.78–0.94), AOD-SL-Perp nasal 0.83 (CI 0.72–0.91), AOD-SL-Vert nasal 0.87 (CI 0.77–0.94), and ITA nasal 0.91 (IC 0.81–0.96). Pentacam AUCs: ACD 0.76 (CI 0.64–0.85), ACV 0.75 (CI 0.63–0.84), and ACA 0.84 (CI 0.74–0.92). No statistical differences between different AUCs. Intraclass correlation coefficient (ICC) of ACA (Pentacam) with ITA temporal (AS-OCT) 0.59 and with nasal ITA nasal (AS-OCT) 0.65.

Conclusion

Both systems show high capacity for non-contact occludable angle detection. But agreement between methods is moderate or low.

Intra-session repeatability of anterior chamber depth across the chamber width using Pentacam Scheimpflug imaging in healthy subjects

PURPOSE

Despite the importance of anterior chamber depth (ACD) measurements in disease and ageing, the repeatability and their threshold for change is not known. Our purpose was to determine the intra-session repeatability of Pentacam Scheimpflug photography for measuring the ACD across the chamber width in healthy subjects and thus inform expected limits of normality.

METHODS

Pentacam Scheimpflug photography was used to obtain ACD measurements at 57 points across the central 8mm of the chamber width from one randomly selected eye of 130 healthy (normal vision and no ocular diseases, except age-normal cataracts) subjects (median age 58.0 years, interquartile range 46.3-63.0 years; 48 males, 82 females). Intra-session ACD measurements were compared. Univariate and multivariate linear regression was performed to identify categorical and continuous variables demonstrating a significant relationship with ACD and its repeatability.

RESULTS

Bland-Altman analyses showed no directional or depth-dependent bias in the difference between the first and second tests (mean bias -0.003 mm, 95% limits of agreement -0.115 to +0.109 mm). Multivariate analysis found gender to be a significant factor (p < 0.0001), but not age (p = 0.69) nor ethnicity (p = 0.65), although the model fit was poor (R²  = 0.004). There were no regional differences in repeatability measures found in males, but six locations in the superior aspect in females were found to be significantly different in their repeatability characteristics. Tolerance limits used to calculate the number of step sizes between <20 and >60-year-old age groups found 8.1-11.5 steps for females, and 7.5-9.2 steps for males.

CONCLUSIONS

Scheimpflug imaging using the Pentacam has excellent intra-session repeatability. Only gender appeared to affect repeatability characteristics, manifesting with a greater number of meaningful steps of change between two extremes of age range in females compared to males, which provides guidance for identifying clinically significant and measurable change between tests.

The effects of cyclopentolate 1% versus tropicamide 1% on anterior segment angle parameters in three refractive pediatric groups

PURPOSE

This study aims to assess the effects of topical tropicamide 1% versus cyclopentolate hydrochloride 1% on the main numerical anterior chamber angle parameters using anterior segment optical coherence tomography (AS-OCT) in myopic, emmetropic, and hyperopic pediatric populations.

METHODS

One hundred eight healthy and non-amblyopic children were enrolled in this prospective study. The children were assigned into three refractive groups of myopia, emmetropia, and hyperopia for both tropicamide and cyclopentolate administrations. Half of the children in three groups were instilled tropicamide 1%, and the remaining halves were instilled cyclopentolate hydrochloride 1%. AS-OCT measurements of the anterior chamber angle in three groups were performed at the temporal areas of the right eyes under similar conditions at baseline, 30 min after tropicamide, and 45 min after cyclopentolate instillations. Main measurements including the angle-opening distance at 500 µm anterior to the scleral spur (AOD500), trabecular iris space area at 500 µm anterior to the scleral spur (TISA500), and scleral spur angle (SSA) were compared between three refractive groups.

RESULTS

The groups were age and gender-matched. The mean baseline spherical equivalents were similar in hyperopia groups of the tropicamide (+2.34 ± 0.44) and cyclopentolate (+2.18 ± 0.32) administrations (p = 0.284), as well as the myopic children administered with tropicamide (-2.68 ± 0.40) and cyclopentolate (-2.74 ± 0.38), (p = 0.406). All baseline measurements of AOD500, TISA500, and SSA measurements were similar in three refractive groups for both tropicamide and cyclopentolate as well as the final measurements and thus measurement changes between two sessions (P > 0.05 for all). Both drops induced an increase of AOD500, TISA500, and SSA measurements in three refractive groups (p < 0.05 for all).

CONCLUSIONS

Cycloplegic effects of topical instillations of tropicamide and cyclopentolate lead to a significant increase in anterior chamber angle measurements of AS-OCT. This similar effect of the drops should be considered for proper clinical assessment in children.

Diagnostic accuracy of AS-OCT vs gonioscopy for detecting angle closure: a systematic review and meta-analysis

Purpose

This study aims to review the literature that compares the accuracy of Anterior Segment-Optical Coherence Tomography (AS-OCT) against gonioscopy in detecting eyes with angle closure. It is currently unclear how AS-OCT fits into clinical practice for detecting angle closure. This is a systematic review and meta-analysis.

Methods

A literature search was performed on Medline, Embase, Scopus and the Cochrane Central Register of Controlled Trials to identify studies that investigated the diagnostic accuracy of AS-OCT in detecting eyes with angle closure as diagnosed by gonioscopy. Eligible studies included in the analysis met stringent inclusion criteria determining the sensitivity and specificity of AS-OCT.

Results

The initial search identified 727 studies, of which 23 were included in the final analysis. We found substantial variation in the parameters being studied and methodologies. The sensitivity of AS-OCT ranged from 46 to 100% (median 87%). Twenty-one studies identified parameters that showed sensitivity above 80%. The specificity ranged from 55.3 to 100% (median 84%).

Conclusion

AS-OCT demonstrates good sensitivity for detecting angle closure. It may provide an avenue to address high rates of undiagnosed angle closure, such as found in developing Asian countries. However, AS-OCT is not yet able to replace gonioscopy. Clinicians should consider whether the diagnostic accuracy of AS-OCT is acceptable for their specific clinical use before adopting it. More studies are needed to determine the utility of AS-OCT, including longitudinal studies to determine the significance of eyes classified to have closed angles by AS-OCT but open on gonioscopy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05271-4.

Effect of High Myopia on Dynamic Changes of Anterior Angle After Pharmacologic Mydriasis in Cataract Patients: A SS-ASOCT Study

Purpose

The purpose of this study was to evaluate the effect of high myopia on anterior angle change after pharmacologic mydriasis in patients with cataract using swept-source anterior segment optical coherence tomography (SS-ASOCT).

Methods

This prospective cross-sectional study continuously recruited patients with cataract aged 40 years and older during the period August 2019 to August 2020. The anterior segment parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular-iris angle (TIA), angle to angle width (ATA), and anterior chamber volume (ACV), were obtained using SS-ASOCT at baseline and 30 minutes after mydriasis. Regression analyses were performed to identify the factors related to the relative change of AOD500 (ΔAOD500).

Results

A total of 938 patients (938 eyes) were included. The AOD500 decreased from 0.46 ± 0.22 mm to 0.40 ± 0.19 mm, with percent ΔAOD500 of -13.59% ± 37.73% (P = 0.005). The patients with high myopia had a smaller reduction of anterior angle parameters, with a percent ΔAOD500 of -22.74% ± 58.09%% in non-high myopic eyes and -0.84% ± 45.47% in high myopic eyes (P < 0.001). The stepwise multivariate regression demonstrated that the smaller reduction of AOD500 were independently associated with younger age (coefficient = -2.11, 95% confidence interval [CI] = -2.59 to -1.64, P < 0.001), presence of high myopia (coefficient = 15.35, 95% CI = 3.63 to 27.07, P = 0.010), greater baseline TISA500 (coefficient = 60.78, 95% CI = 8.75 to 112.82, P = 0.022), and ATA (coefficient = 11.21, 95% CI = 4.53 to 17.89, P = 0.001).

Conclusions

The anterior chamber angle decreased after pharmacologic mydriasis in these patients with cataract. Angle shallowing after pharmacologic mydriasis was significantly less pronounced in high myopic eyes than in non-high myopic eyes.

Translational Relevance

These findings are informative for the relative less risk of angle-closure glaucoma in highly myopic eyes.

Ultrasound biomicroscopy in glaucoma assessment

Ultrasound biomicroscopy (UBM) is an important tool in the diagnosis, evaluation and follow up of glaucoma patients. Even if we are dealing with a primary angle closure glaucoma (PACG) or a primary open angle glaucoma (POAG) patient, the mechanism of angle closure can be revealed by performing an UBM. The device can help differentiate between the two types of glaucoma even in patients with opaque corneas when gonioscopy cannot be performed. Knowing the type of glaucoma is vital, especially regarding an individualized treatment, since each patient is unique and needs to be treated accordingly, in order to prevent glaucomatous optic neuropathy and visual field loss. Abbreviations: AC = anterior chamber, ICE = iridocorneal endothelial syndrome, IOP = intraocular pressure, NTG = normal tension glaucoma, PACG = primary angle closure glaucoma, PC = posterior chamber, PEX = pseudoexfoliation syndrome, POAG = primary open angle glaucoma, UBM = ultrasound biomicroscopy.

Peripheral Anterior Chamber Depth and Angle Measurements Using Pentacam After Implantation of Toric and Non-toric Implantable Collamer Lenses

Purpose: To evaluate the characteristics of peripheral anterior chamber measurements by Pentacam after posterior implantable collamer lenses (ICL) and toric ICL (TICL) with central hole (V4c) implantation.

Methods: Prospective, non-randomized consecutive case series. Forty-six patients undergoing ICL implantation in one eye (Group A) and identically sized TICL in the contralateral eye (Group B) in the Refractive Surgery Center of Eye and ENT Hospital of Fudan University were prospectively included. According to ICL/TICL size, these eyes were further divided into four subgroups. Peripheral anterior chamber depth (PACD) and angle (ACA) in nasal and temporal sides were measured using Pentacam pre-operatively and 12-month post-operatively.

Results: The safety indices were 1.34 ± 0.32 and 1.25 ± 0.16 and the efficacy indices were 1.20 ± 0.24 and 1.19 ± 0.19 for ICL and TICL groups, respectively. There was no significant difference in pre-operative PACD or ACA between the two groups. Post-operative PACD and ACA were significantly lower than pre-operative values. Variations of PACD and ACA of TICL group were significantly larger than those of ICL group. The change of ACA for 13.2 mm lenses was significantly larger than that of 12.6 mm lenses. Pre-operative CACD and vault were significantly associated with post-operative PACD, while pre-operative ACA and vault were significantly associated with post-operative ACA.

Conclusions: Variations of PACD and ACA were greater in eyes after TICL (V4c) implantation compared with identically sized ICL (V4c) implantation and with larger size than smaller size lens implantation. Pre-operative anterior chamber structure and vault affect post-operative PACD and ACA.

Anterior Chamber Angle Assessment Techniques: A Review

Assessment of the anterior chamber angle (ACA) is an essential part of the ophthalmological examination. It is intrinsically related to the diagnosis and treatment of glaucoma and has a role in its prevention. Although slit-lamp gonioscopy is considered the gold-standard technique for ACA evaluation, its poor reproducibility and the long learning curve are well-known shortcomings. Several new imaging techniques for angle evaluation have been developed in the recent years. However, whether these instruments may replace or not gonioscopy in everyday clinical practice remains unclear. This review summarizes the last findings in ACA evaluation, focusing on new instruments and their application to the clinical practice. Special attention will be given to the comparison between these new techniques and traditional slit-lamp gonioscopy. Whereas ultrasound biomicroscopy and anterior segment optical coherence tomography provide quantitative measurements of the anterior segment’s structures, new gonio-photographic systems allow for a qualitative assessment of angle findings, similarly to gonioscopy. Recently developed deep learning algorithms provide an automated classification of angle images, aiding physicians in taking faster and more efficient decisions. Despite new imaging techniques made analysis of the ACA more objective and practical, the ideal method for ACA evaluation has still to be determined.

Characterizing Current Attitudes and Practices for Human Subject Safety in Studies Involving Pupil Dilation

Standards in pupil dilation practices regarding the safety of human subjects are not present in vision research despite the potential for significant adverse effects. We developed two surveys to examine current practices around pupil dilation among vision researchers and individuals associated with oversight of human subjects research. While both groups note an absence of adverse events associated with pupil dilation, vision researcher practices differed with informed consent use and measures taken to minimize complications. For Institutional Review Boards, general risk assumption associated with dilation was not unanimous and there was a lack of specific guidance available to researchers for minimizing risk. These results uncover the need for standardized practices regarding pupil dilation in human subjects research.

Assessment of angle closure spectrum disease as a continuum of change using gonioscopy and anterior segment optical coherence tomography

PURPOSE

Studies examining the anterior chamber angle and angle closure disease often compare quantitative angle information obtained using anterior segment optical coherence tomography (ASOCT) with one of several ordinal scales derived using gonioscopy. We test the assumption that the ordinal gonioscopic angle grades have equal step sizes and can be analysed using metric statistics.

METHODS

The medical records of 214 consecutive patients who were referred for assessment of the anterior chamber angle were prospectively examined using gonioscopy and ASOCT (Spectralis Optical Coherence Tomography, OCT, www.heidelbergengineering.com). Anterior chamber angle parameters (angle opening distance, AOD, and trabecular-iris space area, TISA at 500 and 750 microns) were extracted from ASOCT images using a semi-automated segmentation algorithm written on MATLAB (www.mathworks.com). We first matched the quantitative values for each gonioscopic grade (0-4, from no structures visible to ciliary body visible) and described the frequency distributions to determine separability. We then applied a grade-agnostic clustering algorithm to determine the concordance between algorithm-clustered groups (using solely quantitative data) and those obtained using gonioscopy.

RESULTS

The frequency distributions of the quantitative ASOCT parameters for each angle grade were mostly non-parametric and displayed unique distribution characteristics, with a floor effect seen for grade 0 and the lack of a ceiling effect seen for grades 3 and 4. Although we found significant differences in quantitative values across the five angle grades using the frequency distributions, some pairwise comparisons were indistinguishable (such as grades 0 and 1, and grades 3 and 4) due to the overlaps in distributions. On average, differences in quantitative values were consistent between gonioscopic grade steps, but there remained substantial variability that confounds prediction of change between ordinal steps. The clustering algorithm showed approximately 10% of cases with the same group assignment as that of the gonioscopic grade, improving slightly to 30% when the top 5% of quantitative data were excluded from analysis.

CONCLUSIONS

Our results do not necessarily support the assumption that the ordinal scales used in gonioscopy can be interpreted using an interval scale. We highlight the need for better methods of describing the course and risk of angle closure spectrum disease to identify disease progression and conversion, where gonioscopy remains the gold standard.

Optical coherence tomography of the Tokay gecko (Gekko gecko) eye

OBJECTIVE

To provide images of the anterior and posterior structures of the gecko eye using spectral domain optical coherence tomography (SD-OCT).

ANIMALS AND PROCEDURES

Eight ophthalmologically normal Tokay geckos (Gekko gecko) were used. The nose-cloaca distance and body weight were measured for each gecko. Tomographic images were obtained using SD-OCT without the use of anesthetic or mydriatic agents. The central corneal thickness (CCT), the anterior chamber depth (ACD), and the length of the conus papillaris (CP) were manually measured using OCT images. The thickness of the retinal nerve fiber layer (RNFL) around the CP and the retinal thickness in all four quadrants (superior, nasal, inferior, and temporal areas) were automatically measured using the OCT software program.

RESULTS

The mean values of the nose-cloaca distance and body weight were 13.8 ± 0.9 cm and 41.3 ± 9.0 g, respectively. The mean values of CCT, ACD, and CP length were 177.6 ± 20.9 µm, 1205.0 ± 79.9 µm, and 1546.4 ± 208.8 µm, respectively. The mean value of RNFL thickness was 52.0 ± 8.2 µm, and the superior region was the thickest. The mean value of total retinal thickness was 202.5 ± 9.4 µm, and the temporal region was the thickest.

CONCLUSIONS

Tomographic images of the anterior and posterior segments of the living gecko eye could be obtained using the OCT unit. Multiple retinal layers and anatomical features of the CP were identified.

Cluster analysis reveals patterns of age-related change in anterior chamber depth for gender and ethnicity: clinical implications

Purpose

To identify patterns of age‐, gender‐ and refractive‐ related changes in Scheimpflug‐based anterior chamber depth across the central 8 mm of chamber width, to derive normative models, potentially useful for angle closure disease diagnosis.

Methods

This was a retrospective, cross‐sectional study. Scheimpflug photography was used to obtain anterior chamber depth measurements at 57 points across the central 8 mm of the chamber width from one eye of each healthy subject (male Caucasians (n = 189), female Caucasians (n = 186), male Asians (n = 165) and female Asians (n = 181)). Sliding window and nonlinear regression analysis was used to identify the age‐related changes in chamber depth. Hierarchical cluster analysis was used to identify test locations with statistically identical age‐related shifts, which were used to perform age‐correction for all subjects, resulting in normative distributions of chamber depth across the chamber width. The model was examined with and without the contribution of spherical equivalent refractive error.

Results

Distinct clusters, demonstrating statistically indistinguishable age‐related changes of chamber depth over time, were identified. These age‐related changes followed a nonlinear regression (fifth or sixth order polynomial). Females tended to have a greater rate of chamber depth shallowing. Incorporating refractive error into the model produced minimal changes to the fit relative to the ground truth. Comparisons with cut‐offs for angle closure from the literature showed that ageing alone was insufficient for identifying angle closure disease.

Conclusions

Age‐, ethnicity‐ and gender‐related differences need to be acknowledged in order to utilise anterior chamber depth data for angle closure disease diagnosis correctly. Ageing alone does not adequately account for the angle closure disease process.

Effect of cyclopentolate versus tropicamide on anterior segment angle parameters in three refractive groups

CLINICAL RELEVANCE

Frequent clinical application of cycloplegia in clinical practice makes it essential to assess how this condition influences anterior segment angle parameters.

BACKGROUND

This study aims to compare the effects of cyclopentolate and tropicamide on anterior segment angle parameters in three adult refractive groups.

METHODS

Sixty healthy individuals were recruited and assigned into three refractive groups according to inclusion criteria. At baseline visit, anterior segment angle parameters were measured using anterior segment optical coherence tomography in the right eye. All measurements were repeated at two separate visits, one week apart, after administration of tropicamide 1% and cyclopentolate 1% at similar conditions. Main outcome measures were angle-opening distance, trabecular iris angle, trabecular iris space area and anterior chamber depth. Anterior segment angle parameters were recorded at temporal areas (180 degrees).

RESULTS

Sixty participants (29 men and 31 women, age: 27.82 ± 4.71-years) completed the experiment. Baseline mean spherical equivalents were +1.52 ± 1.20 D, -0.04 ± 0.33 D and -1.91 ± 0.91-D in hyperopic, emmetropic and myopic groups, respectively. No statistically significant differences were found between tropicamide and cyclopentolate for all angle parameters in three refractive groups. Both drops induced an increase in all parameters in three refractive groups. Analysis between refractive groups revealed that a more hyperopic refraction was associated with less trabecular iris angle, angle-opening distance and anterior chamber depth parameters in baseline, after tropicamide and cyclopentolate instillations.

CONCLUSIONS

Topical application of cycloplegic eye drops in healthy individuals leads to small but significant changes in anterior chamber depth and anterior segment angle parameters, regardless of refractive status. Moreover, lower values of anterior chamber depth and anterior segment angle parameters in hyperopic individuals after administration of cycloplegic drops should be taken into account during biometric measurement and phakic intraocular lens implantation. Due to shorter effect and recovery time and less ocular/systemic reaction of tropicamide versus cyclopentolate, tropicamide could be a recommended cycloplegic agent for diagnostic and therapeutic procedures.

Modeling of gonioscopic anterior chamber angle grades based on anterior segment optical coherence tomography

Background

To quantitatively assess anterior chamber angle (ACA) structure by anterior segment optical coherence tomography (AS-OCT) and develop a model to evaluate angle width as defined by gonioscopy.

Methods

The ACAs of each quadrant were evaluated by gonioscopy, classified by the Scheie grading system, and assigned into one of the three grades: small angle (SA), moderate angle (MA), and large angle (LA). The eyes were imaged by AS-OCT, and ACA structural parameters including angle opening distance at the scleral spur (AODSS) and at 750 μm anterior to the scleral spur (AOD750), trabecular-iris space area at 750 μm anterior to the scleral spur (TISA750), and a newly defined parameter “light intersection distance” (LID), were measured. The ACA structural data were used to construct an ordered logistic regression model for assignment of ACAs to one of the three angle grades. The validity of the model was then tested.

Results

A total of 169 quadrants from 53 subjects were included in the analysis, of which 111 quadrants were included in the modeling data and 58 in the testing data. In pairwise comparisons of SA, MA, and LA by ANOVA, the measured parameters were as follows: AOD750 (0.174 ± 0.060 vs. 0.249 ± 0.068 vs. 0.376 ± 0.114 mm; P < 0.001), TISA750 (0.075 ± 0.035 vs. 0.117 ± 0.036 vs. 0.181 ± 0.062 mm²; P < 0.001), and LID (− 0.300 ± 0.187 vs. -0.085 ± 0.170 vs. 0.122 ± 0.156 mm; P < 0.001). The ACA grading model based on LID showed a relatively high correction rate of 72.4%, and the model efficiency, calculated using the receiver operating characteristic, showed an area under the curve of 0.740. Weighted kappa statistics showed a good agreement for multiple ACA grades (0.772).

Conclusions

The AS-OCT-based multiple ACA grades model was demonstrated as a non-contact approach for ACA assessment with high speed and high spatial resolution, providing guidance for diagnosis of angle closure.

Non-contact tests for identifying people at risk of primary angle closure glaucoma

BACKGROUND

Primary angle closure glaucoma (PACG) accounts for 50% of glaucoma blindness worldwide. More than three-quarters of individuals with PACG reside in Asia. In these populations, PACG often develops insidiously leading to chronically raised intraocular pressure and optic nerve damage, which is often asymptomatic. Non-contact tests to identify people at risk of angle closure are relatively quick and can be carried out by appropriately trained healthcare professionals or technicians as a triage test. If the test is positive, the person will be referred for further specialist assessment.

OBJECTIVES

To determine the diagnostic accuracy of non-contact tests (limbal anterior chamber depth (LACD) (van Herick test); oblique flashlight test; scanning peripheral anterior chamber depth analyser (SPAC), Scheimpflug photography; anterior segment optical coherence tomography (AS-OCT), for identifying people with an occludable angle.

SEARCH METHODS

We searched the following bibliographic databases 3 October 2019: CENTRAL; MEDLINE; Embase; BIOSIS; OpenGrey; ARIF and clinical trials registries. The searches were limited to remove case reports. There were no date or language restrictions in the searches.

SELECTION CRITERIA

We included prospective and retrospective cross-sectional, cohort and case-control studies conducted in any setting that evaluated the accuracy of one or more index tests for identifying people with an occludable angle compared to a gonioscopic reference standard.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed data extraction and quality assessment using QUADAS2 for each study. For each test, 2 x 2 tables were constructed and sensitivity and specificity were calculated. When four or more studies provided data at fixed thresholds for each test, we fitted a bivariate model using the METADAS macro in SAS to calculate pooled point estimates for sensitivity and specificity. For comparisons between index tests and subgroups, we performed a likelihood ratio test comparing the model with and without the covariate.

MAIN RESULTS

We included 47 studies involving 26,151 participants and analysing data from 23,440. Most studies were conducted in Asia (36, 76.6%). Twenty-seven studies assessed AS-OCT (analysing 15,580 participants), 17 studies LACD (7385 participants), nine studies Scheimpflug photography (1616 participants), six studies SPAC (5239 participants) and five studies evaluated the oblique flashlight test (998 participants). Regarding study quality, 36 of the included studies (76.6%) were judged to have a high risk of bias in at least one domain.The use of a case-control design (13 studies) or inappropriate exclusions (6 studies) raised patient selection concerns in 40.4% of studies and concerns in the index test domain in 59.6% of studies were due to lack of masking or post-hoc determination of optimal thresholds. Among studies that did not use a case-control design, 16 studies (20,599 participants) were conducted in a primary care/community setting and 18 studies (2590 participants) in secondary care settings, of which 15 investigated LACD. Summary estimates were calculated for commonly reported parameters and thresholds for each test; LACD ≤ 25% (16 studies, 7540 eyes): sensitivity 0.83 (95% confidence interval (CI) 0.74, 0.90), specificity 0.88 (95% CI 0.84, 0.92) (moderate-certainty); flashlight (grade1) (5 studies, 1188 eyes): sensitivity 0.51 (95% CI 0.25, 0.76), specificity 0.92 (95% CI 0.70, 0.98) (low-certainty); SPAC (≤ 5 and/or S or P) (4 studies, 4677 eyes): sensitivity 0.83 (95% CI 0.70, 0.91), specificity 0.78 (95% CI 0.70, 0.83) (moderate-certainty); Scheimpflug photography (central ACD) (9 studies, 1698 eyes): sensitivity 0.92 (95% CI 0.84, 0.96), specificity 0.86 (95% CI 0.76, 0.93) (moderate-certainty); AS-OCT (subjective opinion of occludability) (13 studies, 9242 eyes): sensitivity 0.85 (95% CI 0.76, 0.91); specificity 0.71 (95% CI 0.62, 0.78) (moderate-certainty). For comparisons of sensitivity and specificity between index tests we used LACD (≤ 25%) as the reference category. The flashlight test (grade 1 threshold) showed a statistically significant lower sensitivity than LACD (≤ 25%), whereas AS-OCT (subjective judgement) had a statistically significant lower specificity. There were no statistically significant differences for the other index test comparisons. A subgroup analysis was conducted for LACD (≤ 25%), comparing community (7 studies, 14.4% prevalence) vs secondary care (7 studies, 42% prevalence) settings. We found no evidence of a statistically significant difference in test performance according to setting. Performing LACD on 1000 people at risk of angle closure with a prevalence of occludable angles of 10%, LACD would miss about 17 cases out of the 100 with occludable angles and incorrectly classify 108 out of 900 without angle closure.

AUTHORS' CONCLUSIONS

The finding that LACD performed as well as index tests that use sophisticated imaging technologies, confirms the potential for this test for case-detection of occludable angles in high-risk populations. However, methodological issues across studies may have led to our estimates of test accuracy being higher than would be expected in standard clinical practice. There is still a need for high-quality studies to evaluate the performance of non-invasive tests for angle assessment in both community-based and secondary care settings.

Altered effective connectivity of primary visual cortex in primary angle closure glaucoma using Granger causality analysis

Background

Previous neuroimaging studies demonstrated that primary angle closure glaucoma patients were associated with abnormal intrinsic brain activity in primary visual cortex (V1).

Purpose

The purpose of this study was to investigate the effective connectivity patterns of V1 in patients with primary angle closure glaucoma.

Material and Methods

Thirty-seven patients with primary angle closure glaucoma (20 men, 17 women) and 36 healthy controls (20 men, 16 women) closely matched for age, sex, and education, underwent resting-state MRI scans. A voxel-wise Granger causality analysis method was performed to explore different effective connectivity pattern of V1 between the two groups.

Results

Compared with healthy controls, patients with primary angle closure glaucoma showed decreased effective connectivity from the left V1 to left cuneus and increased effective connectivity from the left V1 to left precentral gyrus and right supplementary motor area. Meanwhile, patients with primary angle closure glaucoma showed decreased effective connectivity from left precentral gyrus to left V1 and right frontal middle gyrus to left V1. In addition, patients with primary angle closure glaucoma showed a decreased effective connectivity from the right V1 to left cuneus/calcarine and increased effective connectivity from the right V1 to left inferior frontal gyrus and right caudate. Meanwhile, patients with primary angle closure glaucoma showed decreased effective connectivity from right middle frontal gyrus/precentral gyrus to right V1 and left precentral gyrus to right V1.

Conclusion

Our results highlighted that patients with primary angle closure glaucoma had abnormal effective connectivity between V1 and higher visual area, motor cortices, somatosensory cortices, and frontal lobe, which indicated that they might present with abnormal top-down modulations, visual imagery, vision-motor function, and vision-related higher cognition function.

Frequency-specific oscillations synchronization in primary angle-closure glaucoma

Background

Previous neuroimaging studies demonstrated that patients with primary angle-closure glaucoma were accompanied by abnormal neuronal activity.

Purpose

To investigate frequency-dependent local oscillations synchronization in primary angle-closure glaucoma using the regional homogeneity method.

Material and Methods

In total, 37 individuals with primary angle-closure glaucoma (20 men, 17 women) and 37 normal-sighted controls (20 men, 17 women) closely matched in age, sex, and education underwent resting-state MRI scans. We compared the different regional homogeneity values in full band (0.01–0.08 Hz) and two different frequency bands (slow-4: 0.027–0.073 Hz and slow-5: 0.010–0.027 Hz) between two groups.

Results

Compared to the normal-sighted group, the primary angle-closure glaucoma group showed decreased regional homogeneity values in the left calcarine and left postcentral in full band. The primary angle-closure glaucoma group showed increased regional homogeneity values in the bilateral superior medial frontal lobe in the slow-4 band. The primary angle-closure glaucoma group exhibited decreased regional homogeneity values in the right calcarine in the slow-5 band. Specifically, we found that the regional homogeneity values in the right superior frontal lobe were greater in the slow-4 than in the slow-5 band, whereas regional homogeneity in the left calcarine, right pallidum, left inferior occipital gyrus, left superior occipital gyrus, left postcentral/angular gyrus, left paracentral lobule, left superior parietal gyrus, and right precuneus gyrus were greater in the slow-5 than in the slow-4 band.

Conclusion

Primary angle-closure glaucoma groups showed abnormal regional homogeneity in visual network (calcarine) and default mode network (superior medial frontal lobe) at two frequency bands. Moreover, the regional homogeneity signals in slow-5 band showed closely related to the severity of individuals with primary angle-closure glaucoma.

Anterior Chamber Angle Evaluation Using Gonioscopy: Consistency and Agreement between Optometrists and Ophthalmologists

SIGNIFICANCE

In our intermediate-tier glaucoma care clinic, we demonstrate fair to moderate agreement in gonioscopy examination between optometrists and ophthalmologists, but excellent agreement when considering open versus closed angles. We highlight the need for increased consistency in the evaluation and recording of angle status using gonioscopy.

PURPOSE

The consistency of gonioscopy results obtained by different clinicians is not known but is important in moving toward practice modalities such as telemedicine and collaborative care clinics. The purpose of this study was to evaluate the description and concordance of gonioscopy results among different practitioners.

METHODS

The medical records of 101 patients seen within a collaborative care glaucoma clinic who had undergone gonioscopic assessment by two clinicians (one optometrist and either one general ophthalmologist [n = 50] or one glaucoma specialist [n = 51]) were reviewed. The gonioscopy records were evaluated for their descriptions of deepest structure seen, trabecular pigmentation, iris configuration, and other features. These were compared between clinicians (optometrist vs. ophthalmologist) and against the final diagnosis.

RESULTS

Overall, 51.9 and 59.8% of angles were graded identically in terms of deepest visible structure when comparing between optometrist versus general ophthalmologist and optometrist versus glaucoma specialist, respectively. The concordance increased when considering ±1 of the grade (67.4 and 78.5%, respectively), and agreement with the final diagnosis was high (>90%). Variations in angle grading other than naming structures were observed (2.0, 30, and 3.9% for optometrist, general ophthalmologist, and glaucoma specialist, respectively). Most of the time, trabecular pigmentation or iris configuration was not described.

CONCLUSIONS

Fair to moderate concordance in gonioscopy was achieved between optometrists and ophthalmologists in a collaborative care clinic in which there is consistent feedback and clinical review. To move toward unified medical records and a telemedicine model, improved consistency of record keeping and angle description is required.

Optical coherence tomography of the retina, nerve fiber layer, and optic nerve head in dogs with glaucoma

OBJECTIVE

To evaluate the retina and optic nerve head (ONH) in canine eyes predisposed to glaucoma using optical coherence tomography (OCT).

ANIMALS

Twenty-five eyes (24 dogs).

METHODS

Measures of peripapillary retinal, retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) thickness and ONH parameters were obtained in vivo by OCT of the unaffected eye in dogs diagnosed with unilateral primary glaucoma (predisposed; n = 12) and compared with measures of healthy control eyes (normal; n = 13). Repeatability and intrarater reliability were explored using intraclass correlation coefficients (ICC).

RESULTS

Compared to normal eyes, predisposed eyes had a thinner retina in the temporal (P = 0.005), inferior quadrants (P = 0.003), and decreased inner retinal thickness (superior: P = 0.003, temporal: P = 0.001, inferior: P < 0.001, nasal: P = 0.001). Predisposed eyes had a thinner RNFL compared to normal eyes (P = 0.005), and when analyzed in quadrants, it was thinner in the superior (P < 0.001), temporal (P = 0.034), and nasal quadrants (P = 0.001). Repeatability (ICC 0.763-0.835) and intrarater reliability (ICC 0.824-0.942) were good to excellent for measures of retinal thickness and adequate for RNFL measurements (ICC 0.701-0.798). Reliable measurements of optic disk area were obtained and were similar between groups (P = 0.597). Measurements of parameters relying on automated software detection (GCC, optic cup, optic rim) had inadequate repeatability and reliability.

CONCLUSION

Statistically significant differences in retinal and RNFL thicknesses were identified in normal and predisposed eyes. Reliable and consistent measurements of variables with manual adjustment of software detected parameters were obtained. Validation of OCT as a diagnostic tool for clinical assessment in canine glaucoma is warranted.

A collaborative care pathway for patients with suspected angle closure glaucoma spectrum disease

BACKGROUND

Currently, no specific collaborative care pathway exists that distinguishes open angle glaucoma from narrow angle or angle closure disease. This study evaluates a newly developed referral and collaborative care pathway specifically for patients with angle closure spectrum disease.

METHODS

The medical records of consecutive patients referred to the Centre for Eye Health for glaucoma assessment were examined, six months before (Pre Suite) and after (Post Suite) the introduction of a novel referral pathway for anterior chamber angle assessment (Angle Suite). Patient demographic and clinical data, the referral letter and practitioner characteristics were extracted.

RESULTS

Angle Suite (n = 77) patients had an appointment much sooner compared to Pre (n = 383) and Post Suite (n = 425) patients (p < 0.0001). Following the introduction of Angle Suites, there was a reduction of incidental angle closure disease found in routine, non-angle closure glaucoma assessment. Onward referral was required by 36.4 per cent of patients referred for suspected angle closure disease, while the rest could be discharged back into the community (13.0 per cent) or reviewed at the Centre for Eye Health (50.6 per cent). Multinomial logistic regression found that the presence of an angle description in the referral letter improved the true positive rate for angle closure disease (p < 0.0001).

CONCLUSIONS

The clinical pathway may reduce the number of incidental angle closure patients and improved the timeliness of appropriate clinical care delivered to a subset of patients who may benefit from prompt medical attention. This pathway provides an opportunity for appropriately staffed and equipped collaborative care clinics to reduce the burden on tertiary level ophthalmic facilities.

The prevalence and determinants of glaucoma among 40 years and older Saudi residents in the Riyadh Governorate (except the Capital) - A community based survey

Purpose

To evaluate the prevalence of glaucoma and its determinants among adult Saudi Residents aged 40 years and older in the Riyadh Governorate (except the Capital).

Methods

A cluster-based sample of randomly selected citizens from six primary health center catchment areas were examined between 2014 and 2015. Data were collected on their glaucoma management. Assessment included measurement of intraocular pressure, optic nerve head evaluation and gonioscopy. Glaucoma suspects were referred for visual field testing.

Result

A total of 940 citizens were examined and 124 had glaucoma. The prevalence of glaucoma was 5.6% [95% Confidence interval (CI): 5.43–5.75] with an estimated 3758 cases of glaucoma in study area. Males had a significantly higher prevalence (7.62%) than females (3.48%). Glaucoma was not significantly associated to diabetes [Odds ratio (OR) = 1.1; (95% CI: 0.8–1.7); P = 0.5]. The variation in the prevalence of glaucoma by age group was not significant (P = 0.2). Open angle of anterior chamber was in 78% of glaucoma cases. The coverage of glaucoma management was 27.8%. Among known glaucoma patients were 69% were treatment-complaint. Of 124 glaucoma patients, 29 (23.5%) were aware of their diagnosis. Mild and moderate visual impairment was in 67% and 8 (6.5%) glaucoma patients while one (0.8%) patient was bilateral blind.

Conclusion

The prevalence of glaucoma was high. Identified determinants should be noted and accordingly a public health approach for early detection and adequate management is recommended.

Anterior Chamber Angle, Volume, and Depth in a Normative Cohort-A Retrospective Cross-Sectional Study

Purpose: The purpose of the study was to determine the distribution of the anterior chamber angle (ACA) within a population-based study sample in Germany and to find correlations between age, sphere, and biometric parameters of the anterior chamber. Patients and Methods: A total of 500 eyes, approximately 100 eyes per decade starting with patient age of 20 years, of 463 patients with an average age of 45.2 ± 14.1 (±values subsequent represent standard deviation) years without any known history of ocular diseases, surgery, or optic nerve head excavation or hypoplasia were included. ACAs, volume, and depth were correlated to age and sphere. Scheimpflug images (Pentacam, Oculus) with automatically measured ACAs were compared to manually measured angles (Bland Altman analysis) in this healthy population. Results: The mean manually measured ACA was 26.5° ± 3.9°; the highest average angle was found in the temporal position with 28.1° ± 4.9°, while the lowest average angle was found in nasal superior position with 25.7° ± 4.7°. Statistical analysis showed an average difference of +11.4° nasal and +12.1° temporal between the automatic measurements and the manually measured angles (P < 0.01). The analysis also revealed an independent inverted correlation between age (correlation coefficient between -0.28 and -0.38) and sphere (correlation coefficient between -0.44 and -0.51) of the participants and the anterior chamber volume, angle, and anterior chamber depth (P < 0.01 for all correlations). Conclusion: The ACA width manually measured is considerably less compared to automated imaging and formerly reported values. There is a significant difference in the ACA dependent on the position of measurement (superior, nasal, inferior, and temporal) with the average angle being inversely correlated to age and sphere. Abbreviations: AC: anterior chamber ACA: anterior chamber angle ACV: anterior chamber volume ACD: anterior chamber depth AAC: acute angle closure OAG: open-angle glaucoma OCT: optical coherence tomography ACG: angle-closure glaucoma MIGS: microinvasive glaucoma surgery PACS: primary angle-closure suspects.

Diagnostic Accuracy of Van Herick Technique to Detect Pre-Disease States of Primary Angle Closure Glaucoma in a Resource Constraint Region

OBJECTIVES

To critically evaluate diagnostic accuracy of the van Herick (vH) technique in detection of gonioscopically occludable angle in a rural population and to explore ways to improve accuracy of the technique Methods: The study cohort was formed by two-stage cluster random sampling. Peripheral anterior chamber depth grading was performed, using both traditional and modified (photographic comparison) vH techniques, under dark adapted and standard lighting conditions by a comprehensive ophthalmologist masked to the clinical features. The cut-off criterion for vH test was 25% of peripheral corneal thickness. The reference standard was dark room 4-mirror indentation gonioscopy performed by an experienced glaucoma specialist. This study adhered to the STARD guidelines for reporting diagnostic accuracy studies.

RESULTS

We studied 111 eyes of 111 participants. The median age was 62 years. The angle was occludable by gonioscopy in 69 (62%) eyes; 58 eyes were primary angle closure suspects and 11 were primary angle closure patients. The likelihood ratio (95% confidence interval (CI)) of the positive (LR+) and negative (LR‒) result by the traditional vH technique was 5.17 (2.43, 11) and 0.30 (0.20, 0.46), respectively. The LR+ by reducing and LR‒ by elevating the cut-off grade of the traditional vH technique were 9.4 (2.3, 37.4) and 0.08 (0.02, 0.31), respectively. The area under receiver operating characteristic curve did not differ significantly by photographic comparison or lighting condition (p = 0.13).

CONCLUSIONS

vH grading can be considered as a triage test before gonioscopy. The value of the vH technique to the diagnostic strategy is discussed.

Frequency-dependent neural activity in primary angle-closure glaucoma

OBJECTIVE

In this study, we aimed to investigate the frequency-dependent spontaneous neural activity in primary angle-closure glaucoma (PACG) using the amplitude of low-frequency fluctuations (ALFF) method.

PATIENTS AND METHODS

In total, 52 PACG individuals (24 males and 28 females) and 52 normal-sighted controls (NS; 24 males and 28 females) who were closely matched in age, sex, and education underwent resting-state magnetic resonance imaging scans. A repeated-measures ANOVA and post hoc two-sample t-tests were conducted to analyze the different ALFF values in two different frequency bands (slow-4, 0.027-0.073 Hz and slow-5, 0.010-0.027 Hz) between the two groups. Pearson's correlation analysis was conducted to reveal the relationship between the mean ALFF values and clinical variables in the PACG group.

RESULTS

Compared to the NS group, the PACG group had high ALFF values in the right inferior occipital gyrus and low ALFF values in the left middle occipital gyrus, left precentral gyrus, and left postcentral gyrus in the slow-4 band. The PACG group had high ALFF values in the right inferior occipital gyrus and low ALFF values in the left inferior parietal lobule, left postcentral gyrus, and right precentral/postcentral gyrus in the slow-5 band. Specifically, we found that the abnormal ALFF values in the bilateral posterior cingulate gyrus and bilateral precuneus were higher in the slow-4 than in the slow-5 band, whereas ALFF in the bilateral frontal lobe, right fusiform, and right cerebellum posterior lobe were higher in the slow-5 than in the slow-4 band. The greater mean ALFF values of the right inferior occipital gyrus were associated with smaller retinal nerve fiber layer thickness and greater visual fields in PACG group in the slow-4 band.

CONCLUSION

Our results highlighted that individuals in the PACG group showed abnormal spontaneous neural activities in the visual cortices, sensorimotor cortices, frontal lobe, frontoparietal network, and default mode network at two frequency bands, which might indicate impaired vision and cognition and emotion function in PACG individuals. These findings offer important insight into the understanding of the neural mechanism of PACG.

An evidence-based approach to the routine use of optical coherence tomography

Optical coherence tomography is an imaging technology that has revolutionised the detection, assessment and management of ocular disease. It is now a mainstream technology in clinical practice and is performed by non-specialised personnel in some settings. This article provides a clinical perspective on the implications of that movement and describes best practice using multimodal imaging and an evidence-based approach. Practical, illustrative guides on the interpretation of optical coherence tomography are provided for three major diseases of the ocular fundus, in which optical coherence tomography is often crucial to management: age-related macular degeneration, diabetic retinopathy and glaucoma. Topics discussed include: cross-sectional and longitudinal signs in ocular disease, so-called 'red-green' disease whereby clinicians rely on machine/statistical comparisons for diagnosis in managing treatment-naïve patients, and the utility of optical coherence tomography angiography and machine learning.

Low Sensitivity of the Van Herick Method for Detecting Gonioscopic Angle Closure Independent of Observer Expertise

PURPOSE

To evaluate the diagnostic performance characteristics of the Van Herick assessment (VHA) for identifying angle closure compared to gold-standard gonioscopy, as conducted by trained observers of varying expertise.

DESIGN

Reliability analysis.

METHODS

Patients (n = 131) from a glaucoma referral clinic aged ≥50 years without prior ocular surgery or iridotomy underwent unilateral VHA by 1 of 11 trained ophthalmic technicians, followed by VHA and indirect gonioscopy by 1 of 15 ophthalmology residents and 1 of 4 glaucoma specialist attending physicians. Observers were masked to others' gradings. Cohen's kappa (κ) assessed test reproducibility. VHA sensitivity and specificity for identifying gonioscopic angle closure were calculated.

RESULTS

Mean patient age was 62.0 ± 8.7 years, 56% of patients were male, and 84% were African American. Angles were gonioscopically closed in 14.5% of eyes. Moderate agreement was observed comparing technician or resident VHA to attending VHA (κ = 0.48 and κ = 0.56, respectively). Resident and attending gonioscopy demonstrated excellent agreement (κ = 0.94). Sensitivities of technician, resident, and attending VHA for detecting angle closure were 57.9% (95% confidence interval: 34.0%-78.9%), 78.9% (53.9%-93.0%), and 68.4% (43.5%-86.4%), respectively. Specificities were 88.5% (80.3%-93.6%), 88.2% (80.3%-93.3%), and 87.5% (79.6%-92.8%), respectively.

CONCLUSIONS

VHA, even when performed by experienced ophthalmologists, misses a substantial proportion of angle closure while incorrectly identifying roughly 1 in 8 open-angle eyes as closed. These results suggest that clinical assessment of anterior chamber angle configuration is best accomplished with gonioscopy.

Anterior segment Scheimpflug imaging for detecting primary angle closure disease

PURPOSE

To evaluate the capability of anterior segment Scheimpflug imaging for detecting primary angle closure disease (PACD): primary angle closure suspect, primary angle closure, and primary angle closure glaucoma, using cutoff points derived from reference databases of healthy subjects.

METHODS

Eighty-seven patients with PACD and 49 age-matched control subjects were included. We evaluated the sensitivity and specificity of anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) to differentiate patients with PACD from controls. Additionally, the study's raw data was analyzed via receiver operating characteristic curves for comparison.

RESULTS

One standard deviation from the normative data's mean values was used as the cutoff point and yielded a sensitivity and specificity of 96.2% and 92.6% for ACD, 97.1% and 75.9% for ACV, and 93.3% and 72.2% for ACA, respectively. Receiver operating characteristic analysis of the raw data showed the area under the curve to be 0.984, 0.975, and 0.931 for ACD, ACV, and ACA, respectively.

CONCLUSIONS

Our study demonstrated that the parameters of anterior segment Scheimpflug imaging, particularly ACD, accurately discriminate PACD. This was the first study to validate the device's normative data in a separate population. With its high reproducibility, ease of use, non-invasiveness, and speed, anterior segment Scheimpflug imaging is a potentially powerful screening tool for PACD.

Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography

Purpose

To assess the interdevice agreement between swept-source Fourier-domain and time-domain anterior segment optical coherence tomography (AS-OCT).

Methods

Fifty-three eyes from 41 subjects underwent CASIA2 and Visante OCT imaging. One hundred eighty–degree axis images were measured with the built-in two-dimensional analysis software for the swept-source Fourier-domain AS-OCT (CASIA2) and a customized program for the time-domain AS-OCT (Visante OCT). In both devices, we examined the angle opening distance (AOD), trabecular iris space area (TISA), angle recess area (ARA), anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). Bland-Altman plots and intraclass correlation (ICC) were performed. Orthogonal linear regression assessed any proportional bias.

Results

ICC showed strong correlation for LV (0.925) and ACD (0.992) and moderate agreement for ACW (0.801). ICC suggested good agreement for all angle parameters (0.771–0.878) except temporal AOD500 (0.743) and ARA750 (nasal 0.481; temporal 0.481). There was a proportional bias in nasal ARA750 (slope 2.44, 95% confidence interval [CI]: 1.95–3.18), temporal ARA750 (slope 2.57, 95% CI: 2.04–3.40), and nasal TISA500 (slope 1.30, 95% CI: 1.12–1.54). Bland-Altman plots demonstrated in all measured parameters a minimal mean difference between the two devices (−0.089 to 0.063); however, evidence of constant bias was found in nasal AOD250, nasal AOD500, nasal AOD750, nasal ARA750, temporal AOD500, temporal AOD750, temporal ARA750, and ACD. Among the parameters with constant biases, CASIA2 tends to give the larger numbers.

Conclusions

Both devices had generally good agreement. However, there were proportional and constant biases in most angle parameters. Thus, it is not recommended that values be used interchangeably.

Contemporary approach to the diagnosis and management of primary angle-closure disease

The primary angle-closure disease spectrum varies from a narrow angle to advanced glaucoma. A variety of imaging technologies may assist the clinician in determining the pathophysiology and diagnosis of primary angle closure, but gonioscopy remains a mainstay of clinical evaluation. Laser iridotomy effectively eliminates the pupillary block component of angle closure; however, studies show that, in many patients, the iridocorneal angle remains narrow from underlying anatomic issues, and increasing lens size often leads to further narrowing over time. Recent studies have further characterized the role of the lens in angle-closure disease, and cataract or clear lens extraction is increasingly used earlier in its management. As a first surgical step in angle-closure glaucoma, lens extraction alone often effectively controls the pressure with less risk of complications than concurrent or stand-alone glaucoma surgery, but may not be sufficient in more advanced or severe disease. We provide a comprehensive review on the primary angle-closure disease nomenclature, imaging, and current laser and surgical management.

Anterior Chamber Angle Tissue as an Incidental Optical Coherence Tomography Finding in a Large Healthy Caucasian Child Population

PURPOSE

The aim of this study was to describe the presence of anterior chamber angle (ACA) tissue as an incidental optical coherence tomography (OCT) finding in healthy children.

METHODS

For this cross-sectional study, we reviewed Fourier-domain OCT images obtained in 422 children, who were chosen as candidates for inclusion in a prior study, and who visited our clinic for a routine vision test. The presence of angle tissue was assessed in the nasal and temporal quadrants. On tomographies showing angle tissue, several measurements were made, including ACA width and trabecular meshwork length and size.

RESULTS

Hyperreflective tissue was observed in the ACA recess in 14 eyes of 13 children subjected to OCT (3.3%). This tissue was only present in 1 quadrant. The mean age of the affected children was 10.1±2.5 years (range, 7 to 14); 69% were female patients. Spherical refractive error was -0.5 to +1.75 D. ACA width was 45.9±9.1 (24.8 to 57.9) in the nasal quadrant and 44.3±10.1 (23.9 to 60.1) in the temporal quadrant. Trabecular meshwork length and size were 494±94 μm (322 to 732) and 0.064±0.018 mm (0.03 to 0.11), respectively. In all 13 children, intraocular pressure was ≤18 mm Hg, the appearance of the optic nerve head was normal, and none had a family history of glaucoma.

CONCLUSIONS

We, here, report the incidental observation of angle tissue in a small percentage of healthy Caucasian children. The follow-up of these children in future work could clarify the possible clinical implications of this observation.

Agreement between Pentacam and optical coherence tomography in the assessment of iridocorneal angle width in a large healthy population

PURPOSE

To analyze the agreement between Pentacam and optical coherence tomography (OCT) in the assessment of trabecular-iris angle (TIA) width in a large population of normal subjects.

METHODS

A cross-sectional study was performed in 989 right eyes of 989 healthy subjects. The trabecular-iris angle (TIA) was measured in the temporal and nasal quadrants using the Pentacam (Oculus, Wetzlar, Germany), a device based on Scheimpflug technology and RTVue 100 OCT (Optovue, Fremont, CA, USA). Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to evaluate agreement between these devices.

RESULTS

Mean age was 49.1±15.2 years (18-84); 61% were women and spherical error range was -14 to 8.25. TIA could be measured by OCT in 94.9% and 94.1% in the temporal and nasal quadrants, with a mean value of 35.8±13.2 degrees (2.5-78.7) and 35.7±12.9 degrees (2.2-76.8) respectively. TIA was able to be measured by Pentacam in 95.2% and 95% in the temporal and nasal quadrants and means were 35.7±7.3 degrees (11-74.2) and 36.4±8.2 degrees (14.5-64) respectively. An ICC of 0.378 (95% confidence interval [CI], 0.322-0.431) and 0.589 (95% CI 0.546-0.629) for the temporal and nasal quadrants was obtained, showing moderate agreement between the devices. Bland-Altman plots revealed that, compared with OCT, Pentacam tends to overestimate measurements in narrow angles and underestimate these in open angles.

CONCLUSIONS

Agreement between OCT and Pentacam was mediocre, indicating the two devices are not interchangeable when used to measure angle width.