Narrow Anterior Chamber Angle Research Articles

Intraocular pressure increase after Nd:YAG laser capsulotomy and anterior segment optical coherence tomography analysis.

This study is to determine whether post-procedure intraocular pressure (IOP) increase is associated with the anterior chamber angle in cases of Neodymium: yttrium-aluminum garnet (Nd: YAG) laser capsulotomy. The study included 51 eyes with posterior capsule opacification. Initial IOP values of the patients were compared with IOP values without intraocular pressure-lowering administration at the end of the 1st hour, 1st day, 3rd day, and 7th day after Nd:YAG laser capsulotomy. The anterior segment angle configuration was evaluated using anterior segment optical coherence tomography analysis without dilatation before the procedure. The anterior chamber angle (ACA) and angle opening distances of 500 and 750 μm (AOD500 and AOD750) in the nasal and temporal quadrants were examined. The mean pre-laser IOP value only increased significantly at 1st hour post-laser (13.02 ± 3.02 mmHg vs 14.16 ± 4.07 mmHg, p = 0.016). In eyes with ACA below 40° in both the nasal and temporal quadrants, mean IOP increased significantly at 1st hour post-laser (p = 0.025 and p = 0.032, respectively), while it was not significant in eyes with ACA above 40° (p > 0.05). No correlation was found between ACA, AOD500, and AOD750 values and IOP changes at the first hour (p > 0.05). Except for the first hour after Nd:YAG laser capsulotomy, no significant increase in IOP was observed. This elevation was higher in eyes with ACA less than 40°. In patients with a narrow ACA, first-hour follow-up may be beneficial in terms of susceptibility to increased IOP.

Anterior Segment Biometry in Primary Angle Closure Glaucoma Patients with Visual Field Progression: Comparison between Malays and Chinese.

To compare anterior segment biometry parameters in progress and non-progress primary angle closure glaucoma (PACG) among Malay and Chinese patients. A cross-sectional study was conducted between November 2015 and December 2016 involving 75 patients with PACG (43 Malays and 32 Chinese) who were recruited from a single glaucoma center in Malaysia. Ocular examination included anterior segment biometry measurements on the selected eye. Axial length (AL) and anterior chamber depth (ACD) measurement was done using a noncontact partial coherence interferometer (IOL Master, Carl Zeiss, Germany). Anterior chamber angle (ACA) was measured by Anterior Segment-OCT (Spectralis Heidelberg, Germany). Humphrey visual field (HVF) 24-2 analysis of the same eye was conducted and compared with the HVF when diagnosis was made. Progression of PACG patients was assessed according to the Hodapp, Parrish and Anderson's (HPA) classification, they were then divided into progress and non-progress groups. Comparison of anterior segment biometry parameters between Malay and Chinese PACG patients with and without progression was analyzed using independent T test. Multivariate ANOVA analysis was used to compare the anterior segment parameters between progress and non-progress PACG patients, with adjustment for age, gender, lens status, family history and presence of diabetes mellitus. Chinese PACG patients have significant shorter AL (22.18 mm ± 0.76) and narrower ACA (11.96° ± 6.00) compared to Malay PACG patients. Among the progress group, Chinese PACG patients have significant shorter AL, shallower ACD and narrower ACA compared to Malays. However, after controlling for confounding factors, there was significant difference in ACA between Malay and Chinese PACG. There was also no significant difference of ocular biometry measurement between Chinese and Malay patients in progress and non-progress group. There was racial influence in ocular biometry measurement in PACG patients. Chinese have significant narrower ACA compared to Malays. Serial AS-OCT monitoring is important in management of PACG. Neoh FP, Azhany Y, Siti-Azrin AH, et al. Anterior Segment Biometry in Primary Angle Closure Glaucoma Patients with Visual Field Progression: Comparison between Malays and Chinese. J Curr Glaucoma Pract 2023;17(1):3-8.

Safety of intraocular pressure measurement using air-puff tonometer after implantable collamer lens implantation

To determine the safety of intraocular pressure (IOP) measurement using a noncontact tonometer in patients who have undergone implantable collamer lens (ICL) implantation. Eye, Ear, Nose, and Throat Hospital. Prospective study. 64 eyes of 33 patients (aged 28.4 ± 5.2 years) scheduled for ICL implantation were enrolled. The anterior segment parameters and vault were obtained using an anterior segment analyzer. A noncontact air-puff tonometer was used preoperatively and at 1 day and 1 week postoperatively to assess corneal biomechanical properties and IOP. The Corvis ST was used to evaluate the distance between the corneal endothelial layer and iris (E-Iris Dist) and the distance between the corneal endothelial layer and ICL (E-ICL Dist) when the cornea was deformed by the airflow. The mean anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) decreased significantly postoperatively (all P values <.001). The E-ICL Dist values measured 1 day and 1 week postoperatively were similar ( P = .107). However, a contact between the corneal endothelium and ICL was detected in 2 eyes when the cornea was deformed to the highest concavity. The 1-day postoperative vault, ACV, ACA, and preoperative stress-strain index contributed significantly ( P = .001, P = .023, P = .010, and P = .019, respectively) to determine the distance. The mean E-iris Dist values decreased significantly at 1 day and 1 week postoperatively ( P < .001). The 1-week postoperative vault and ACD contributed significantly ( P = .025 and P = .039, respectively) to determine the E-Iris Dist value. Excessively high vault, shallow ACD, narrow ACA, low ACV, and soft cornea are associated with a lower E-ICL distance and thus may be risk factors for a contact between the corneal endothelium and ICL during IOP measurement. Although there is no proof that the contact may cause any risks to the endothelium, noncontact air-puff tonometry should be avoided in eyes predicted by the study model to be at risk of this occurring. Contact IOP measurements using Goldmann applanation tonometers or dynamic contour tonometers may be alternate methods of IOP measurements in extreme cases.

Characteristics of Anterior Segment in Congenital Ectopia Lentis: An SS-OCT Study.

Purpose To investigate the characteristics of anterior chamber angle parameters in congenital ectopia lentis (CEL) patients and to evaluate the sensitivity and specificity of anterior segment parameters in distinguishing CEL from healthy controls. Setting. Zhongshan Ophthalmic Center, Guangzhou, China. Design Cross-sectional study. Methods 35 CEL patients and 35 age- and sex-matched healthy controls were recruited. Axial length (AL) and anterior segment parameters including anterior chamber width (ACW), angle open distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA), and trabecular-iris angle (TIA) were measured. All the above parameters and the ratio index of angle parameters, which was defined as the angle parameter value of the narrower side to that of the contralateral side, were compared between CEL and controls. Receiver operating characteristic (ROC) curves were also plotted to evaluate the diagnostic performance of anterior chamber angle parameters in CEL patients. Results All angle parameters of the contralateral side to the dislocated lens side were significantly smaller than those of the dislocated lens side in CEL (all P < 0.05). For the diagnostic performance of anterior chamber angle parameters, the ratio index of TIAr500 combined with TIAr750 had the best diagnostic performance for CEL screening (AUC = 0.798), and TIAr500 of 0.887 and TIAr750 of 0.917 were detected to be the optimal cut-off points, representing a sensitivity of 89.8% and specificity of 68.7%. Conclusion The contralateral side to the dislocated lens side in the CEL had a narrower anterior chamber angle. TIAr500 combined with TIAr750 is the optimal combination strategy for ectopia lentis screening.

Intraocular Pressure and Its Relation to Ocular Geometry: Results From the Gutenberg Health Study.

PurposeThe purpose of this study was to investigate the association between intraocular pressure (IOP) and ocular geometry.MethodsThe Gutenberg Health Study is a population-based cohort study in Mainz, Germany. Study participants underwent a comprehensive ophthalmologic examination including noncontact tonometry, objective refraction, optical biometry, and Scheimpflug imaging of the anterior segment at the first 5-year follow-up examination (in 2012–2017). Multivariable linear regression analysis was carried out to determine associations of IOP and geometric parameter of the human phakic eye, namely central corneal thickness (CCT), corneal curvature, anterior chamber depth (ACD), lens thickness, and axial length. In addition, the relationship of IOP and the anterior chamber angle (ACA) width was analyzed.ResultsThere were 6640 participants with phakia (age 57.3 ± 10.2 years, 49.1% women) that were included in this cross-sectional analysis. Mean IOP was 14.8 ± 2.9 mm Hg in the right eyes and 14.9 ± 2.9 mm Hg in the left eyes. IOP increased with higher CCT, greater posterior segment length, higher age (all P < 0.001), thicker lens (P = 0.003), and female sex (P = 0.05), whereas the ACD was not associated with higher IOP. The IOP increased with a narrower ACA in univariable analysis (P < 0.001), but not in adjusted analysis in subjects with an open angle.ConclusionsIOP values are related to ocular geometry, as shown in this population-based study on Caucasian subjects. Thus, knowledge of the architecture of the eye is an important factor when measuring IOP. Longitudinal evaluation will analyze whether some of these parameters are also risk factors for the development of glaucoma.

To measure angle of anterior chamber using Topcon SD-OCT: A new technique

The proposed new method of measuring angle of anterior chamber is an effective method of measuring the angles. Identification of narrow anterior chamber angle is important for glaucoma screening and prophylactic treatment prevents acute angle closure glaucoma event.Aim of this study wasto measure the angle of anterior chamber using Topcon spectral domain optical coherence tomography (SD OCT).In this cross-sectional study 120 normal subjects above the age of 40 years were enrolled. The study was done at the tertiary health care center of central Indian. All volunteers had visual acuity of at least 6/9 with no ocular diseases. Using OCT the angle opening distance (AOD-500), trabecular–iris angle (TIA) and trabecular-iris space area (TISA-500) were measured. In this study the mean AOD was 0.430 µm in nasal and 0.433 µm in temporal quadrant. The mean TISA in nasal was 0.405 µm and temporal quadrant was 0.408 µm. While the mean trabecular iris angle (TIA) was 26.9° in nasal and 26.01° in temporal quadrant. The study proved that the proposed method of measuring AOD, TISA, TIA is the effective method as the Topcon-2000 OCT does not have any inbuilt software like that of other ASOCT machines.

Evaluation of Anterior Segment Parameters in Pseudoexfoliation Disease Using Anterior Segment Optical Coherence Tomography

To compare anterior segment and angle parameters between pseudoexfoliation syndrome (PEX) and PEX glaucoma (PEXG) and normal control subjects using anterior segment optical coherence tomography (AS-OCT) imaging. Cross-sectional study. One hundred and two subjects with PEXG, PEX, and normal eyes as the control group were recruited from an academic referral institution. All subjects underwent a complete ophthalmologic examination, axial length measurement, and AS-OCT imaging. Anterior segment and angle parameters were evaluated. After excluding 4 eyes because of poor imaging of the scleral spur, data from 34 eyes with PEXG, 33 eyes with PEX, and 31 eyes of normal control subjects were analyzed. Anterior chamber depth was significantly shallower in eyes with PEXG compared with eyes of control subjects (P < .001). The differences in anterior chamber angle parameters (AOD500, AOD750, TISA500,and TISA750) were significant among study groups, with lower values in the PEXG group compared with the PEX and control subject groups. Lens vault (mean [mm]±SD) was higher in the PEXG (0.46 ±0.21) and PEX (0.427 +0.28) groups compared with the control group (0.305+ 0.20). PEXG eyes have the narrowest anterior chamber angle parameters. There is a progressive decrease in angle parameters from control subjects to the PEX group to the PEXG group. Narrow anterior chamber angle and anterior chamber depth may have a role in the progression of PEX to PEXG. Detection of narrow angle in these patients may help clinicians manage the disease more properly.

New capabilities of optical coherence tomography in the diagnostics of primary angle-closure glaucoma

INTRODUCTION. Recently, posterior vitreous detachment (PVD) was suggested as a fundamental pathologic process in primary angle-closure glaucoma (PACG) in morphologically predisposed patients with anatomically narrow anterior chamber angle.PURPOSE. To study the role of PVD in the development and clinical manifestation of PACG in anatomically predisposed eyes and to assess the capabilities of posterior segment optical coherence tomography (PS-OCT) in PACG diagnostics.MATERIALS AND METHODS. Thirty eyes with newly diagnosed stage I-II PACG and thirty eyes predisposed to PACG (with narrow anterior chamber angle without glaucoma signs) were enrolled in the study. All patients underwent ophthalmological examination, Hyams test, ocular ultrasound (OU) and PS-OCT.RESULTS. PVD with retrohyaloid space (RHS) formation was revealed in all PACG eyes. Positive Hyams test was in 86.67% eyes with PACG, and 13.33% were negative. All the eyes with PVD as a result of Hyams test experienced RHS enhancement correlating with IOP rise. Despite the negative results of Hyams test in some PACG eyes with PVD — glaucomatous optic neuropathy signs were present. Possible causes are discussed.PVD with RHS formation was revealed in 53.33% predisposed to PACG eyes — all with positive result of Hyams test. The other 46.67% eyes predisposed to PACG had negative Hyams test, no PVD and no RHS.CONCLUSION. Obtained results confirm a new theory of PACG etiopathogenesis suggesting PVD with PGS to be the essential mechanism of POAG development in morphologically predisposed eyes. PS-OCT appears to be crucial in PACG early diagnostics.

The prevalence and break down of narrow anterior chamber angle pathology presenting to a general ophthalmology clinic.

To approximate the breakdown of narrow anterior chamber angle conditions, on general ophthalmology clinics, in the predominantly white population of the South East Kent region in the United Kingdom.A review was done of all patients attending a secondary care ophthalmology general clinic over a 3-year period. Patients were assessed with: slitlamp biomicroscopy with indentation gonioscopy; SD optical coherence tomography, Humphrey visual field analyzer, and high frequency ultrasound and categorized into various narrow angle conditions. These were: narrow Van Herrick but open angle; primary narrow angle but nonoccludable; primary angle closure suspect; primary angle closure; chronic narrow angle glaucoma; plateau iris configuration; plateau iris syndrome, and phacomorphic narrow angle.A total of 14,520 patients were referred to the clinic, of those 10,491 attended and were analyzed. Six hundred seventy four (6.4%) of the patients had some form of narrow angle condition in at least 1 eye. The majority of these patients were at relative low risk of pathology such as nonoccludable narrow angles (359/53.3%) and narrow Van Herrick but open angles (93/13.8%). 8.8% of all the narrow angle patients had primary angle closure suspect or primary angle closure. Plateau iris pathology was seen in 68 (10.1%) of patients with 18 (26%) having confirmed plateau iris syndrome after peripheral iridotomy. Phacomorphic pathology was confirmed in 75 (11.1%) patients.Narrow angle patients form a significant proportion (6.4%) of those attending general ophthalmology clinic in the predominantly white population in the South East Kent Region of the United Kingdom. The majority of these (67.1%) are at a relatively low risk of developing acute or chronic angle closure glaucoma. Of the remaining patients 8.8% have primary angle closure suspect or primary angle closure and 2.9% have already progressed to chronic narrow angle closure glaucoma. Plateau iris pathology and phacomorphic glaucoma account for the remainder of the presentations.

Changes in ocular morphology after cataract surgery in open angle glaucoma patients

The purpose of this study was to evaluate intraocular pressure (IOP) pre- and postoperatively, together with anterior chamber angle (ACA) parameters and biometrical results in cataract patients with or without open angle glaucoma (OAG). The prospective observational case–control study included 15 eyes with cataract and OAG in the glaucoma group and 25 eyes with only cataract in control group. Examination included full ophthalmic evaluation, IOP, ocular biometry and anterior segment optical coherence tomography measuring ACA pre- and 6 months postoperatively. OAG patients had a larger absolute IOP reduction compared to control group. Anterior chamber depth (ACD) and ACA width significantly increased in both groups. The OAG group had a tendency of narrower ACA preoperatively, but overall ACA parameters did not differ in either group pre- and postoperatively. The ACD change after surgery correlated with ACA parameters in the control group, but not in OAG group. Axial length was shorter postoperatively in the control group, but remained similar in the OAG group. Absolute IOP reduction was more pronounced in cataract patients with OAG than in cataract patients without glaucoma. ACD and ACA postoperatively increased in both groups and AL shortening was observed in non-OAG in cataract group.

English

BACKGROUND Glaucoma is the second most leading cause of visual loss in the world. Different socio epidemiological parameters like gender, age, socio-economic status, educational status etc. has been directly linked to occurrence of glaucoma in previous studies. Review of the western literature showed that the risk factors associated with glaucoma were high intra ocular pressure (IOP), low blood pressure, low ocular perfusion pressure, narrow anterior chamber angles, thin corneas, pseudoexfoliation, a low body mass index (BMI), and myopia. We need to evaluate the clinical and epidemiological factors affecting primary open angle glaucoma. METHODS Records of patients with a diagnosis of primary open-angle glaucoma (POAG) were studied. All data, addressing demographics (gender, age and skin colour), socioeconomic status, educational status, emotional status and clinical information concerning risk factors for developing glaucoma (family history of glaucoma, hypertension and diabetes mellitus) and any treatment history (e.g., corticosteroid intake) were noted. Findings from visual acuity examination, refraction, detailed anterior segment examination by slit lamp, fundus examination with 90 D, gonioscopy, applanation tonometry, VF examination by automated perimetry and A-scan USG were also carefully taken into account. RESULTS A total 920 patients were enrolled of which 67.94 % were males and 57.6 % were from urban population. 18.7 % cases had positive family history. Most of the patients came from lower and middle-income group (43.48 % and 48.37 % respectively). Cup-disc ratio of majority of eyes was found to be more than 0.30 (97.29 %). Different grades of disc changes and field changes were noted. Cupdisc ratio asymmetry of more than 0.20 was found in 355 (38.59 %) eyes. Paracentral and / or arcuate scotoma was detected in 585 eyes (31.80 %). CONCLUSIONS Understanding the socio-demography and socio-economy helps in early diagnosis and better assessment of the disease severity in POAG. KEYWORDS Glaucoma, POAG, CDR, Visual Fields

Automatic Anterior Chamber Angle Classification Using Deep Learning System and Anterior Segment Optical Coherence Tomography Images.

PurposeThe purpose of this study was to develop a software package for the automatic classification of anterior chamber angle using anterior segment optical coherence tomography (AS-OCT).MethodsAS-OCT images were collected from subjects with open, narrow, and closure anterior chamber angles, which were graded based on ultrasound biomicroscopy (UBM) results. The Inception version 3 network and the transfer learning technique were applied in the design of an algorithm for anterior chamber angle classification. The classification performance was evaluated by fivefold cross-validation and on an independent test dataset.ResultsThe proposed algorithm reached a sensitivity of 0.999 and specificity of 1.000 in the judgment of closed and nonclosed angles. The overall classification of the proposed method in open angle, narrow angle, and angle-closure classifications reached a sensitivity of 0.989 and specificity of 0.995. Additionally, the sensitivity and specificity reached 1.000 and 1.000 for angle-closure, 0.983 and 0.993 for narrow angle, and 0.985 and 0.991 for open angle.ConclusionsThe experimental results showed that the proposed method can achieve a high accuracy of anterior chamber angle classification using AS-OCT images, and could be of value in future practice.Translational RelevanceThe proposed deep learning-based method that automate the classification of anterior chamber angle can facilitate clinical assessment of glaucoma.

Анатомо-функциональные особенности глаз детей со второй степенью рубцовой ретинопатии недоношенных после лазерной коагуляции сетчатки

Purpose. To evaluate anatomical and functional features of eyes in children with the 2nd stage of cicatricial retinopathy of prematurity (ROP) in long-term period after underwent laser coagulation (LC) of threshold stages of ROP. Material and methods. 18 children with the 2nd stage of cicatricial ROP, who in 2008–2009 underwent LC of retina of threshold stages of ROP (the main group). Selection criterion is absence of traction changes in macular area. In patients aged 8–9 years we studied visual evoked potentials (VEP), performed optical coherence tomography in macular area, and ocular biometry. The control was healthy children of similar age. Results. In the main group we revealed: statistically significant differences in increase of foveal thickness; tendency to reduction of retinal thickness in all segments of macular area; in 89% of cases pathological changes were observed in VEP, despite visually intact optic disc and macula. Conclusion. The features of eyes in children with 2nd stage of cicatricial ROP who underwent LC of retina of threshold stages of ROP, were: increase retinal thickness in fovea, uniform decrease in retinal thickness in other sectors in macular area, more smaller anterior chamber of the eye and narrow anterior chamber angle, than healthy peers. Key words: cicatricial retinopathy of prematurity, retinal thickness, anterior chamber of the eye, visual evoked potentials.

Anterior segment optical coherence tomography imaging and ocular biometry in cataract patients with open angle glaucoma comorbidity

BackgroundAnterior chamber angle anatomy in perspective of ocular biometry may be the key element to intraocular pressure (IOP) reduction, especially in glaucoma patients. We aim to investigate anterior chamber angle and biometrical data prior to cataract surgery in patients with and without glaucoma comorbidity.Materials and methodsThis prospective comparative case-control study included 62 subjects (38 with cataract only and 24 with cataract and glaucoma). A full ophthalmic examination including, Goldmann applanation tonometry, anterior chamber swept source optical coherence tomography (DRI OCT Triton plus (Ver.10.13)) and swept source optical biometry (IOL Master 700 v1.7) was performed on all participants.ResultsWe found that ocular biometry parameters and anterior chamber parameters were not significantly different among groups. However, when we added cut-off values for narrow angles, we found that glaucoma group tended to have more narrow angles than control group. IOP was higher in glaucoma group despite all glaucoma patients having medically controlled IOP. In all subjects, anterior chamber parameters correlated well with lens position (LP), but less with relative lens position, while LP cut-off value of 5.1 mm could be used for predicting narrow anterior chamber angle parameters.ConclusionsCataract patients tend to develop narrow anterior chamber angles. Anterior chamber angle parameters have a positive moderate to strong relationship with lens position. LP may be used predicting narrow angles.

Accommodative Exercises to Lower Intraocular Pressure.

Purpose This study investigated how a conscious change in ocular accommodation affects intraocular pressure (IOP) and ocular biometrics in healthy adult volunteers of different ages. Methods Thirty-five healthy volunteers without ocular disease or past ocular surgery, and with refractive error between −3.50 and +2.50 diopters, were stratified into 20, 40, and 60 year old (y.o.) age groups. Baseline measurements of central cornea thickness, anterior chamber depth, anterior chamber angle, cornea diameter, pupil size, and ciliary muscle thickness were made by autorefraction and optical coherence tomography (OCT), while IOP was measured by pneumotonometry. Each subject's right eye focused on a target 40 cm away. Three different tests were performed in random order: (1) 10 minutes of nonaccommodation (gazing at the target through lenses that allowed clear vision without accommodating), (2) 10 minutes of accommodation (addition of a minus 3 diopter lens), and (3) 10 minutes of alternating between accommodation and nonaccommodation (1-minute intervals). IOP was measured immediately after each test. A 20-minute rest period was provided between tests. Data from 31 subjects were included in the study. ANOVA and paired t-tests were used for statistical analyses. Results Following alternating accommodation, IOP decreased by 0.7 mmHg in the right eye when all age groups were combined (p = 0.029). Accommodation or nonaccommodation alone did not decrease IOP. Compared to the 20 y.o. group, the 60 y.o. group had a thicker ciliary muscle within 75 μm of the scleral spur, a thinner ciliary muscle at 125–300 μm from the scleral spur, narrower anterior chamber angles, shallower anterior chambers, and smaller pupils during accommodation and nonaccommodation (p's < 0.01). Conclusion Alternating accommodation, but not constant accommodation, significantly decreased IOP. This effect was not lost with aging despite physical changes to the aging eye. A greater accommodative workload and/or longer test period may improve the effect.

Prevalence and associated factors of glaucoma in the Russian Ural Eye and Medical Study

To assess the prevalence and associated factors of glaucoma in a Russian population. The population-based Ural Eye and Medical Study included 5899 (mean age 59.0 ± 10.7 years; range 40–94 years). Glaucomatous optic neuropathy was diagnosed using International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria. Among 5545 participants with assessable optic disc photographs, 246 individuals [4.4%; 95% confidence interval (CI) 3.9, 5.0] had glaucoma, with open-angle glaucoma (OAG) in 177 individuals (3.2%; 95% CI 2.7, 3.7) and angle-closure glaucoma (ACG) in 69 individuals (1.2; 95% CI 1.0, 1.5), with IOP > 21 mmHg in 79 (32.1%) patients, and with 80 (32.5%) patients on glaucoma therapy. Glaucoma prevalence increased from 3/485 (0.6%; 95% CI 0.0, 1.3) in the age group of 40–45 years to 33/165 (20.0%; 95% CI 13.8, 26.2) in the group aged 80 + years. Higher OAG prevalence correlated with older age [odds ratio (OR) 1.07; 95% CI 1.04, 1.09; P < 0.001], longer axial length (OR 1.36; 95% CI 1.17, 1.58; P < 0.001), higher intraocular pressure (IOP) (OR 1.18; 95% CI 1.13, 1.23; P < 0.001), higher stage of lens pseudoexfoliation (OR 1.26; 95% CI 1.08, 1.47; P = 0.004) and lower diastolic blood pressure (OR 0.98; 95% CI 0.96, 0.99; P = 0.035). Higher ACG prevalence correlated with older age (OR 1.07; 95% CI 1.03, 1.11; P < 0.001), narrower anterior chamber angle (OR 0.81; 95% CI 0.77, 0.86; P < 0.001), and higher IOP (OR 1.30; 95% CI 1.23, 1.38; P < 0.001). Glaucoma caused moderate to severe vision impairment (MSVI) in 9 (4.9%; 95% CI 1.8, 8.1) out of 184 individuals with MSVI (OAG, n = 7; ACG, n = 2), and blindness in one (9.1%) of 11 blind individuals. In this population from Russia, two thirds of glaucoma patients were not on therapy, and in two thirds of the glaucoma patients IOP was ≤ 21 mmHg. Otherwise, glaucoma prevalence, OAG-to-ACG ratio, and glaucoma associations did not differ markedly from Caucasian and East Asian populations.

Automatic Classification of Anterior Chamber Angle Based on Ultrasound Biomicroscopy Images

Introduction: Evaluating the anterior chamber angle (ACA) is important for the early diagnosis and treatment of primary angle-closure glaucoma. The assessment of ultrasound biomicroscopy (UBM) images usually requires well-trained ophthalmologists and screening for patients with narrow ACA is usually time- and labor-intensive. Therefore, the automatic assessment of UBM could be cost-effective and valuable in daily practice. Objective: The objective of this study is to develop an automatic method for localizing and classifying ACA based on UBM images. Methods: UBM images were collected and a coarse-to-fine method was used to localize the apex of the angle recess. By analyzing the grayscale features around the angle recess, closed angles were identified, and the rest were then classified as open or narrow angles, based on the degree of ACA. Using manual classification as the reference standard, the overall accuracy (OAcc), sensitivity (Sen), specificity (Spe), and balanced accuracy of the automatic classification method were evaluated. Results: A total of 540 UBM images from 290 participants were analyzed. Using these UBM images and the proposed method, the ACA was classified as open, narrow, or closed. During processing, the method localized the angle recess with 95% accuracy. The OAcc of the ACA classification was 77.8%, and the Spe and Sen of our method were 85.8 and 81.7% for angle closure; 88.9 and 75.6% for open angles; 91.9 and 76.1% for narrow angles, respectively. Conclusions: Our method of automatic angle localization and classification based on UBM images is feasible and reliable. The automatic classification of ACA provides a basis and reference for future studies.

Changes of retinal and choroidal capillary blood flow in macula after an acute intraocular pressure elevation.

The aim of this study was to investigate the changes of retinal vessel density (VD) and choriocapillary blood flow area (CBFA) in macula after an acute intraocular pressure (IOP) elevation observed using optical coherence tomography angiography.This was a prospective comparative study of subjects with narrow anterior chamber angles who underwent laser peripheral iridotomies (LPIs). The IOP was measured before and 1 hour after the LPI. The retinal VDs and CBFAs of the macula were measured using optical coherence tomography angiography at the baseline and 1 hour after the LPI.A total of 88 eyes of 88 individuals were enrolled in our study, and 70 eyes of 70 individuals finally completed the study with a mean IOP rise of 10.2 ± 7.5 mm Hg after the LPI. The VDs and areas of foveal avascular zone of all of the subjects did not differ significantly between the measurements obtained at the baseline and 1 hour after the LPI (P > .05). However, there were statistically significant differences in the CBFAs at the baseline and 1 hour after the LPI (P < .05). Based on the magnitude of the rise in the IOP, we divided the subjects into three groups: group A = IOP rise ≤ 10 mm Hg, group B = 10 mm Hg < IOP rise ≤20 mm Hg, and group C = IOP rise > 20 mmHg. The VDs of the macula measured at the baseline were significantly different from the measurements obtained 1 hour after the LPI in group C in either the superficial retinal layer or deep retinal layer (P < .05). Compared with baseline, the CBFAs measured at 1 hour after the LPI were decreased in group B and group C (P < .05).In these subjects with narrow antenior chamber, the blood flow in macula began to be affected with the acute IOP rise greater than 10 mm Hg. It was confirmed that the retina and choroid showed some different ability to regulate its blood flow in response to changes in IOP.

Myopia and anterior segment optical coherence tomography findings in laser-treated retinopathy of prematurity eyes

To evaluate structural features and visual outcomes in eyes with a prior history of laser treatment for retinopathy of prematurity (ROP). Laser-treated eyes for type 1 ROP, preterm monitored eyes, and full-term control eyes were included. LogMAR conversion of Snellen best-corrected visual acuity and spherical equivalent based on cycloplegic refraction were measured in children 5-15years of age. Anterior segment optical coherence tomography (OCT) was used to study structural features, including anterior chamber angle (ACA) in a subset of eyes. A total of 50 eyes of 50 patients were included (19 full-term eyes, 19 laser-treated type 1 ROP eyes, 12 preterm monitored eyes). Of these, 44 eyes had visual outcomes data, and 15 eyes had anterior segment data. There was no significant difference in sex or age at final examination between the three groups. There was no significant difference in gestational age between the laser-treated and preterm monitored groups. Compared with the full-term control group and the preterm monitored group, the laser-treated ROP group had narrower ACA and more myopic refractive error. There was a significant correlation between ACA and spherical equivalent. Laser treatment may affect angle configuration in ROP eyes. Anterior segment OCT is an easy and useful modality that could aid in screening for visually impairing conditions such as myopia and glaucoma in children with ROP.

Using Anterior Segment Optical Coherence Tomography to Assess Angle Anatomy in Patients with Neurofibromatosis Type 1.

Lisch nodules have been identified in more than 90% of patients 16 years or older with neurofibromatosis type 1 (NF1). According to our hypothesis, the presence of Lisch nodules in patients with NF1 might affect the anterior chamber angle (ACA) parameters. The aim of this study was to evaluate the anterior segment angle parameters using anterior segment optical coherence tomography in patients with NF1. A total of 42 eyes from 21 patients with NF1 (study group) and 42 eyes from 21 age- and sex-matched healthy individuals (control group) were included in this study. Angle opening distance at 500 (AOD500) and 750 μm (AOD750) anterior to the scleral spur, ACA, and iris thickness (IT) values were measured in the temporal (T) and nasal (N) quadrants using anterior segment optical coherence tomography. The mean AOD500 and AOD750 values in both quadrants were significantly lower in the study group compared with the control group (T-AOD500: 548 ± 151 vs. 761 ± 288 [P < .001], T-AOD750: 705 ± 175 vs. 921 ± 334 [P < .001], N-AOD500: 599 ± 223 vs. 777 ± 292 [P = .002], and N-AOD750: 756 ± 268 vs. 948 ± 303 [P = .003], respectively). The mean ACA values in both quadrants were significantly narrower in the study group compared with the control group (T-ACA: 29.52 ± 6.36 vs. 40.83 ± 8.90 [P < .001] and N-ACA: 30.05 ± 7.11 vs. 41.29 ± 8.68 [P < .001], respectively). The IT values in both quadrants were significantly thicker compared with the control group (T-IT500: 406 ± 78 vs. 355 ± 59 [P = .001], T-IT750: 453 ± 103 vs. 362 ± 100 [P < .001], N-IT500: 416 ± 93 vs. 353 ± 54 [P < .001], and N-IT750: 437 ± 91 vs. 370 ± 95 [P = .002], respectively). We have revealed lower angle opening distance values in individuals with NF1 than in the healthy ones, as well as significantly narrower ACA values and significantly thicker IT values.