Thin minimal rim width at Bruch's membrane opening is associated with glaucomatous paracentral visual field loss.

PURPOSE: To compare optic nerve head (ONH) measurements in glaucomatous eyes with paracentral visual field (VF) loss to eyes with peripheral VF loss and controls. METHODS: Open-angle glaucoma (OAG) patients with early paracentral VF loss or isolated peripheral VF loss as well as control subjects underwent ONH imaging with swept-source optical coherence tomography (OCT) and retinal nerve fiber layer (RNFL) imaging with spectral-domain OCT. Minimum rim width at Bruch's membrane opening (BMO-MRW), lamina cribrosa depth (LCD), and RNFL thickness were compared among the glaucoma and control groups with one-way analysis of variance, Kruskal-Wallis test, and multiple regression analysis. RESULTS: Twenty-nine eyes from 29 OAG patients (15 early paracentral and 14 isolated peripheral VF loss) and 20 eyes of 20 control subjects were included. The early paracentral and isolated peripheral VF loss groups had similar VF mean deviation (MD) (-5.3±2.7 dB and -3.7±3.0 dB, p=0.15, respectively). Global BMO-MRW was lower in OAG eyes than in controls (193.8±40.0 vs 322.7±62.2 µm, p<0.001), but similar between eyes with early paracentral VF loss and those with isolated peripheral VF loss (187.6±43.4 vs 200.6±36.3 µm; p>0.99). In contrast, the minimal BMO-MRW was lower in eyes with early paracentral loss (69.0±33.6 µm) than in eyes with isolated peripheral loss (107.7±40.2 µm; p=0.03) or control eyes (200.1±40.8 µm; p<0.001). Average and thinnest RNFL thickness did not differ between OAG groups (p=0.61 and 0.19, respectively). Horizontal and vertical LCD did not differ among the OAG groups and controls (p=0.80 and 0.82, respectively). Multivariable linear regression analysis among OAG cases confirmed the association between lower minimal BMO-MRW and early paracentral VF loss (ß=-38.3 µm; 95% confidence interval, -69.8 to -6.8 µm; p=0.02) after adjusting for age, gender, MD, and disc size. CONCLUSION: Thin minimal BMO-MRW may represent a new structural biomarker associated with early glaucomatous paracentral VF loss.

Optic Nerve Head Characteristics in Chronic Angle Closure Glaucoma Detected by Swept-Source OCT.

PURPOSE: To compare structural features in prelaminar and laminar tissues of the optic nerve head (ONH) in chronic angle closure glaucoma (CACG), primary open angle glaucoma (POAG), and control subjects. MATERIALS AND METHODS: ONH imaging was performed using swept-source optical coherence tomography (SS-OCT) for measurements of minimum rim width at Bruch's membrane opening (BMO-MRW), horizontal, and vertical lamina cribrosa depth (LCD). Prelaminar defects, categorized as hole and wedge, and lamina cribrosa (LC) defects were identified. Enhanced depth imaging spectral domain OCT (EDI-OCT) customized to perform high-resolution volume scans was used in conjunction to further characterize prelaminar holes. One eye per subject was analyzed. RESULTS: Eighty subjects (20 CACG, 40 POAG, and 20 controls) were included in the study. CACG and POAG groups had similar mean deviation on Humphrey visual field testing (-6.9 ± 5.1 vs. -6.3 ± 6.0 dB, p > 0.05) and IOP on the day of imaging (14.0 ± 3.1 vs. 13.8 ± 2.7 mmHg, p > 0.05). Thinnest and global BMO-MRW in CACG (120.3 ± 44.8, 225.5 ± 53.9 µm) and POAG (109.7 ± 56.3, 213.8 ± 59.7 µm) groups were lower than controls (200.1 ± 40.8, 308.3 ± 70.8 µm; p < 0.001 for both). Prelaminar holes were most frequent in CACG (65.0%) than POAG (25.0%, p=0.008) or control groups (20.0%, p=0.01). After adjusting for demographic and ophthalmic covariates, CACG was associated with increased odds of having prelaminar holes compared to POAG (odds ratio, 9.79; 95% CI, 2.12-45.19; p=0.003). Hole volume was similar between CACG and POAG (p > 0.05), but the CACG group had more holes per scan than POAG (maximum 2.5 ± 1.9 vs. 1.2 ± 0.4, p=0.02). Prelaminar wedge defects were less common in the CACG than the POAG group (5.0% vs. 37.5%, p=0.02). The CACG group did not differ from controls in laminar characteristics, such as LCD and LC defects. CONCLUSIONS: SS-OCT evaluation of the ONH revealed more frequent prelaminar holes in CACG compared to POAG and control patients.

Comparison of swept-source and enhanced depth imaging spectral-domain optical coherence tomography in quantitative characterisation of the optic nerve head.

AIMS: To compare swept-source optical coherence tomography (SS-OCT) and enhanced depth imaging spectral-domain OCT (EDI-OCT) in quantitative assessment of optic nerve head (ONH) parameters. METHODS: In a cross-sectional study, patients with primary open angle glaucoma (POAG) and age-matched control subjects underwent SS-OCT and EDI-OCT B-scans of the ONH in a single visit. Two masked readers independently measured the horizontal and vertical lamina cribrosa depth (LCDH and LCDV, respectively), as well as thinnest Bruch's membrane opening minimum rim width (BMO-MRW) from SS-OCT and EDI-OCT scans. We assessed agreement between SS-OCT and EDI-OCT measurements by linear regression models, Bland-Altman analysis and concordance correlation coefficients (CCC). Intrareader and inter-reader reproducibility was assessed using intraclass correlation coefficients (ICC). RESULTS: One eye from each of 40 patients with POAG and 20 controls were included. All three ONH measurements were higher on SS-OCT than on EDI-OCT, with significant differences in LCDH (mean difference=31.7 µm, p<0.01) and thinnest BMO-MRW (mean difference=20.5 µm, p<0.01). Linear regression models described the agreement between SS-OCT and EDI-OCT measurements with R2>0.8 for LCDH among both patients with POAG and controls and for thinnest BMO-MRW among patients with POAG. The CCC was >0.8 overall for each parameter. Intrareader and inter-reader ICCs were ≥0.989 and ≥0.964, respectively, for all parameters. CONCLUSIONS: LCDH, LCDV and thinnest BMO-MRW measurements are not interchangeable between SS-OCT and EDI-OCT, but show good intrareader and inter-reader reproducibility and interdevice agreement for quantitative characterisation of the ONH, particularly among patients with glaucoma.

Modified dark room provocative test for primary angle closure.

PURPOSE: To examine the diagnostic value of a modified dark room provocative test (DRPT) in detecting primary closure of the anterior chamber angle. METHODS: The cross-sectional observational prospective clinical study included suspects of primary angle closure. Using anterior segment optical coherence tomography (AS-OCT), we measured the anterior chamber angle configuration at room light and after 3 minutes of dark adaptation. Gonioscopy and Perkin's applanation tonometry were performed in room light conditions at baseline and after 1.5 hours of dark adaptation. The number of closed angle quadrants assessed on AS-OCT images and upon gonioscopy were recorded. The DRPT was positive, if intraocular pressure increased by ≥8 mm Hg after 1.5 hours of dark adaptation. RESULTS: The study included 76 subjects (76 eyes). Among 32 (42%) eyes with a positive DRPT, the number of eyes with an increased number of closed angle quadrants was significantly higher for the OCT examination at 3 minutes of dark adaptation than for gonioscopy at 1.5 hours of dark adaptation [29 (91%) eyes vs 21 (66%) eyes; P=0.01]. Kappa statistics showed a moderate agreement between increased closed angle quadrants obtained both after 3 minutes of dark adaptation (κ=0.44; P<0.001; sensitivity: 90.6%; specificity: 56.8%) and after 1.5 hours of dark room test (κ=0.45; P<0.001; sensitivity: 65.6%; specificity: 79.5%) compared with the final intraocular pressure elevation. Correspondingly, the area under the receiver operator characteristics curve was significantly larger for AS-OCT than for gonioscopy (0.86 vs 0.73; P<0.001) in predicting a positive dark room test. CONCLUSIONS: A modified DRPT with an anterior chamber angle assessment by OCT at 3 minutes of dark adaptation as compared with a gonioscopic angle assessment after 1.5 hours of dark adaptation had a higher diagnostic precision in predicting primary angle closure.

Correlation between pupil diameter and angle configuration in the dark room provocative test.

PURPOSE: To study the associations between changes in pupil diameter and in the anterior chamber angle configuration during the dark room provocative test. METHODS: The study included 70 suspects of primary angle closure (study group) and 40 normal participants (control group). Using anterior-segment optical coherence tomography (AS-OCT), we measured the anterior chamber angle configuration and pupil diameter at 3 minutes and at 1.5 hours of dark adaptation. RESULTS: In the study group, the mean number of closed angle segments was significantly (P<0.001) higher at 3 minutes of dark adaptation (3.9 ± 2.3) than at room light conditions (2.6 ± 2.2) or at 1.5 hours of dark adaptation (3.1 ± 2.1), with no statistically significant (P>0.05) difference between the 2 latter values. In the study group, the pupil diameter was significantly associated with the number of closed angle segments at 3 minutes of dark adaptation (P<0.01), but not at 1.5 hours of dark adaptation (P=0.13). Defined as an increased number of closed angle segments, the dark room test was positive in a significantly higher number of participants at 3 minutes than at 1.5 hours of dark adaptation [44 (63%) eyes vs. 31 (44%) eyes; P<0.05]. Final interocular pressure was statistically better correlated with the angle configuration segments assessed at 3 minutes (correlation coefficient r2=0.33) than at 1.5 hours of dark adaptation (r2=0.21). CONCLUSIONS: After short-term dark adaptation of 3 minutes, the assessment of the anterior chamber angle configuration by AS-OCT is more reliable than as if carried out after a long-term dark adaptation and may be used to identify suspects of primary angle closure.

[Clinical research on movement of intraocular contact lens during accommodation].

OBJECTIVE: To study the movement of intraocular contact lens (ICL) during accommodation. METHODS: Forty one eyes of 41 consecutive patients implanted ICL to correct high myopia were collected. The visual acuity and accommodation power were checked before and after the surgery. The movement of both the ICL and the lens was measured separately at nonaccommodated state and pilocarpine induced accommodation. RESULTS: The uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) improved 3 months after surgery. The mean accommodation power before surgery was (2.12 + or - 1.06) D, and was (4.46 + or - 2.11) D 3 months after surgery. Accommodation power was improved significantly (t = 2.312, P = 0.022). The distance from the posterior surface of ICL to the anterior surface of the lens was (0.48 + or - 0.27) mm at nonaccommodated state, and (0.34 + or - 0.19) mm at drug induced accommodation, the difference was significant (t = 2.104, P = 0.038). The position from corneal endothelium to the anterior surface of ICL had no significant difference at nonaccommodated state and drug induced accommodation (t = 1.165, P = 0.149). Depth of the anterior chamber (from the posterior surface of the cornea to the anterior surface of the lens) between nonaccommodated and drug-induced accommodation had no statistically significant difference (t = 1.821, P = 0.071), but the anterior pole of the lens actually moved forward at drug induced accommodation checked with slit lamp. With ultrasound biomicroscopy we could see that in several surgical eyes, ICL loop contacted with periphery lens both in nonaccommodated state and drug induced accommodation condition. CONCLUSIONS: Although the constriction of pupil induced by pilocarpine decreases the distance from the posterior surface of ICL to the anterior lens surface significantly, there still has enough space to avoid the occurrence of subcapsular cataract. The contact between ICL loop and periphery lens might be one of the causes for periphery lens opacification, but the influence of this contact to the occurrence of central subcapsular opacification still requires further investigation.

Accuracy and repeatability of direct ciliary sulcus diameter measurements by full-scale 50-megahertz ultrasound biomicroscopy.

BACKGROUND: Phakic intraocular lens (pIOL) implantation has been a popular means for the treatment of high ametropia. Measurements of ciliary sulcus diameter is important for pIOL size determining. But till now, no perfect system can directly measure it. The present study was to evaluate the accuracy, repeatability and reproducibility of direct sulcus diameter measurements obtained by a full-scale 50-megahertz (MHz) ultrasound biomicroscopy (UBM). METHODS: A fresh cadaver human eye with a scale marker inserted through the posterior chamber plane from 3 o'clock to 9 o'clock meridian and 30 randomly selected eyes from 30 normal subjects were scanned by full-scale 50-MHz UBM in horizontal meridional scan plane. The distance between the scales and the whole length of the marker inside the cadaver eye were measured by the same observer using the "built-in" measurement tools and the indicating error of instrument was calculated. Reproducibility of the measurement was evaluated in 30 eyes by 2 operators using Blander and Altman plot test. Repeatability was evaluated from 10 successive eyes randomly selected from the 30 eyes by one operator. RESULTS: On a scale of 1 mm, the greatest indicating error was 40 microm; the mean largest indicating error of 1 mm scale from the 10 images was (26 +/- 14) microm; on a scale of 11 mm, the greatest indicating error was 70 microm; the error rate was 0.64%. The mean length of the needle inside the eye of the 10 images was 11.05 mm, with the mean indicating error of 47 microm, the average error rate was 0.43%. For ciliary sulcus diameter measurements in vivo, the coefficient of variation was 0.38%; the coefficients of repeatability for intra-observer and inter-observer measurements were 1.99% and 2.55%, respectively. The limits of agreement for intra-observer and inter-observer measurement were -0.41 mm to 0.48 mm and -0.59 mm to 0.58 mm, respectively. CONCLUSION: The full-scale 50-MHz UBM can be a high accuracy and good repeatability means for direct measuring the ciliary sulcus diameter and useful for size determining of posterior chamber pIOL.

Comparison of the Keratometric Corneal Astigmatic Power after Phacoemulsification: Clear Temporal Corneal Incision versus Superior Scleral Tunnel Incision.

Objective. This is prospective randomized control trial to compare the mean keratometric corneal astigmatism diopter power (not surgical induced astigmatism) among preop and one-month and three-month postop phacoemulcification of either a clear temporal corneal incision or a superior scleral tunnel Incision, using only keratometric astigmatic power reading to evaluate the difference between the two cataract surgery incisions. Methods. 120 patients (134 eyes) underwent phacoemulcification were randomly assigned to two groups: Group A, the clear temporal corneal incision group, and Group B, the superior scleral tunnel incision group. SPSS11.5 Software was used for statistical analysis to compare the postsurgical changes of cornea astigmatism on keratometry. Results. The changes of corneal astigmatic diopter in Groups A and B after 3 month postop from keratometric reading were 1.04 + 0.76 and 0.94 + 0.27, respectively (P = .84 >.05), which showed no statistic significance difference. Conclusion. The incision through either temporal clear cornea or superior scleral tunnel in phacoemulcification shows no statistic difference in astigmatism change on keratometry 3-month postop.