Anterior segment morphology after acute primary angle closure treatment: a randomised study comparing iridoplasty and medical therapy

Comparison of iridolenticular contact area under different light brightness between post primary acute angle closure and cataract eyes

Background

To study the iridolenticular contact area (ILCA) under different light conditions in acute primary angle closure (APAC).

Methods

This cross-sectional, observational study involved 22 unilateral APAC patients and 59 cataract patients (59 eyes). Images of the APAC eyes, fellow eyes and cataract eyes were collected by anterior segment optical coherence tomography (ASOCT) under different light conditions respectively. The ILCA, anterior chamber width (ACW), anterior chamber area (ACA), lens vault (LV), angle opening distance at 750 μm (AOD750), trabecular iris space area at 750 μm (TISA750) and iris area at 750 μm (IA750) were measured using Image J software.

Results

The ILCA of cataract eyes were significantly larger than APAC eyes (4.424 ± 1.208 vs 4.049 ± 2.725mm2, P = 0.034) and fellow eyes (4.424 ± 1.208 vs 3.651 ± 1.629 mm2, P = 0.008) under dark condition. Under dark condition, ILCA of APAC eyes was negatively correlated with AOD750 (r = -0.444, P = 0.038), TISA750 (r = -0.498, P = 0.018). The ILCA of cataract eyes under dark condition was significantly greater than under bright condition (4.424 ± 1.208 vs 2.526 ± 0.992 mm2, P < 0.001).

Conclusions

This study showed that ILCA in both APAC eye and fellow eye were smaller than cataract eye. Future study should focus on both the contact area and force at the interface of lens and iris with larger sample size.

Full circumferential morphological analysis of Schlemm's canal in human eyes using megahertz swept source OCT

We performed full circumferential imaging of the Schlemm's canal (SC) of two human eyes using a Fourier domain mode-lock laser (FDML) based 1.66-MHz SS-OCT prototype at 1060 nm. Eight volumes with overlapping margins were acquired around the limbal area with customized raster scanning patterns designed to fully cover the SC while minimizing motion artifacts. The SC was segmented from the volumes using a semi-automated active contour segmentation algorithm, whose mean dice similarity coefficient was 0.76 compared to the manual segmentation results. We also reconstructed three-dimensional (3D) renderings of the 360° SC by stitching the segmented SCs from the volumetric datasets. Quantitative metrics of the full circumferential SC were provided, including the mean and standard deviation (SD) of the cross-sectional area (CSA), the maximum CSA, the minimum and maximum SC opening width, and the number of collector channels (CC) stemming from the SC.

Efficacy and Safety of Argon Laser Peripheral Iridoplasty and Systemic Medical Therapy in Asian Patients with Acute Primary Angle Closure: A Meta-Analysis of Randomized Controlled Trials

PURPOSE

The purpose of this meta-analysis was to assess the percent reduction in the intraocular pressure (IOP) after argon laser peripheral iridoplasty (ALPI) and systemic medical therapy in patients with acute primary angle closure (APAC).

METHODS

We searched a number of electronic databases, including MEDLINE, EMBASE, PubMed, and Cochrane Library. We searched the electronic databases from the inception of the databases to August 2018. The primary outcomes included the IOP reduction (IOPR), percent reduction in IOP (IOPR%) from baseline to the endpoint and peripheral anterior synechiae (PAS). The secondary outcomes included the cup-to-disc ratio (CDR), mean endothelial count, and percent of patients requiring topical glaucoma medication. Summary weighted mean difference (WMD), odds ratio (OR), and 95% confidence intervals (CIs) were calculated.

RESULTS

Four eligible studies including 183 eyes (92 in the ALPI group and 91 in the medical therapy group) were identified. When comparing ALPI to medical therapy, the WMDs of the IOPR% were 30.03 (95% CI: 21.33 to 38.72, p < 0.00001) at 15 minutes, 27.39 (95% CI: 18.89 to 35.89, p < 0.00001) at 30 minutes, 18.15 (95% CI: 10.63 to 25.68, p < 0.00001) at 1 hour, and 12.91 (95% CI: 4.50 to 21.32, p=0.003) at 2 hours. There was no statistically significant difference between the two groups at 24 hours and at more than 6 months after therapy. Meanwhile, no significant difference was observed in the degree of PAS, CDR, mean endothelial count, and percent of patients requiring topical glaucoma medication after treatment between the two groups.

CONCLUSIONS

Both ALPI and systemic medications were effective with regard to decreasing the IOP. ALPI was more effective in lowering the IOP within the first two hours. Therefore, ALPI may be a better choice for rapidly lowering the IOP in patients with APAC within a short period.

Case Series of Combined iStent Implantation and Phacoemulsification in Eyes with Primary Angle Closure Disease: One-Year Outcomes

PURPOSE

To evaluate the safety and efficacy of combined iStent® trabecular micro-bypass device (Glaukos, Laguna Hills, CA) and phacoemulsification in eyes with primary angle closure disease.

METHODS

A two-center prospective interventional case series of consecutive patients with primary angle closure (PAC) or primary angle closure glaucoma (PACG) on at least one glaucoma medication, who underwent iStent implantation with cataract surgery. Postoperatively, patients were assessed on days 1 and 7, and months 1, 3, 6, and 12. The intraocular pressure (IOP), glaucoma medication use, visual acuity, and the presence of complications were assessed at each visit. Complete success was defined as IOP reduction of at least 20% without the use of glaucoma medications.

RESULTS

Thirty-seven eyes with angle closure disease were included in this study. At 1-year, postoperative mean IOP (14.8 ± 3.94 mmHg) was significantly decreased compared with preoperative medicated (17.5 ± 3.82 mmHg, p = 0.008) and unmedicated (24.6 ± 3.41 mmHg, p < 0.001) IOP. Complete success was achieved in 89.2% of the eyes. The number of glaucoma medications decreased from 1.49 ± 0.77 to 0.14 ± 0.48 (p < 0.001). Preoperative medicated IOP was a risk factor for failure (hazard ratio 3.45, 95% confidence interval 1.52-7.85, p = 0.003), after adjustment for age, gender, and race. The most common postoperative complications were iStent occlusion with iris (27.0%) and hyphema (18.9%). There were no sight-threatening intraoperative or postoperative complications.

CONCLUSION

Combined iStent implantation with cataract surgery was effective in lowering the IOP and the number of glaucoma medications for at least 12 months, with a favorable safety profile.

FUNDING

Glaukos Corporation; NMRC Science Translational and Applied Research (STAR) award.

Identification and Characterization of Imaging Technique Errors and Artifacts Using Anterior-Segment OCT for Irido-Corneal Angle Evaluations in Glaucoma

PURPOSE

Anterior-segment OCT (AS-OCT) platforms provide noninvasive and quantifiable evaluations of anterior chamber angle (ACA) anatomy. Although these ACA measurements have been validated with high repeatability and reproducibility, there is a paucity of data previously published regarding the technique errors and artifacts (TEA) that may occur during imaging of the ACA. The purpose of this study was to report on the types and frequency of imaging TEA that are seen in ACA evaluation of a large cohort of patients with open-angle glaucoma.

DESIGN

Retrospective, cross-sectional design.

PARTICIPANTS

Images were obtained with AS-OCT from 5082 eyes of 2541 patients with glaucoma and were reviewed at the Doheny Image Reading Center (DIRC).

METHODS

Images had been captured using AS-OCT devices from 4 different manufacturers (Zeiss Cirrus [Oberkochen, Germany], Heidelberg Spectralis [Heidelberg, Germany], Optovue RTVue [Fremont, CA], or Zeiss Visante). All images were analyzed by 2 independent and certified DIRC image readers for angle opening distance under Schwalbe's line (SL-AOD), and then re-reviewed by a DIRC-certified principal investigator to adjudicate nonconsensus measurements. Images were defined to have TEA when image readers were unable to confidently measure the SL-AOD.

MAIN OUTCOME MEASURES

Type and frequency of TEA in the AS-OCT image.

RESULTS

Of 5082 eyes reviewed, 208 images (4.09%) were found to have TEA that restricted proper visualization of irido-corneal angle structures and measurements of SL-AOD. The most common TEA was that the image readers were unable to identify Schwalbe's line (74% of TEA images). Other common TEA included poor visualization of the anterior iris surface (15%), misaligned scan location (11%), irregular corneal irregularities (5%), and illumination-related pupillary abnormalities (4%).

CONCLUSIONS

This large-scale study presents the types and frequency of TEA found in AS-OCT-derived angle images. More than 95% of the images reviewed were usable for the quantification of irido-corneal angle measurements. Knowing the common types of TEA may help in enhancing the training of both human image readers and in the design of automated algorithms to improve image acquisition and image interpretation parameters. This will become especially useful as AS-OCT becomes more widely used in clinical practice for anterior chamber assessment.

Medium-term Anatomical Results of Laser Peripheral Iridoplasty: An Anterior Segment Optical Coherence Tomography Study

Aim

To evaluate by anterior segment optical coherence tomography (AS-OCT) the medium-term (mean duration 3.2 years) anatomical changes in the anterior chamber angle (ACA) after laser peripheral iridoplasty.

Materials and methods

This is a longitudinal, retrospective case series of 31 eyes of 31 patients with primary angle-closure suspicion, primary angle closure (PAC), or primary angle-closure glaucoma (PACG) who underwent laser peripheral iridoplasty. All patients had persistent iridotrabecular contact (ITC) despite the presence of a patent peripheral iridotomy (PI). An AS-OCT was performed in dark conditions before and after laser iridoplasty. Quadrants of ITC, intraocular pressure (IOP), and the AS-OCT parameters of the temporal and nasal ACAs were measured and analyzed.

Results

Prior to iridoplasty, the average number of quadrants of ITC was 3.3. At the first postiridoplasty visit (mean duration 6.8 weeks), this reduced to 1.7 quadrants but increased to 1.9 by the final follow-up visit (mean duration 3.2 years). Twenty-five patients (80.1%) had less ITC at the first postlaser visit increasing to 27 (87.1%) patients by the final visit. Two (6.5%) required a second iridoplasty, while 3 (9.7%) required cataract surgery. All parameters of angle width showed a statistically significant increase in magnitude. All patients maintained IOP ≥ 21 mm Hg throughout the follow-up period.

Conclusion

Iridoplasty is a useful adjunct in widening the ACA, particularly in those with persistent angle closure after iridotomy but with no cataract. While not successful in all patients, it can act as a temporizing measure to widen the drainage angle until such time that cataract surgery can be performed.

Clinical significance

Laser peripheral iridoplasty can be used as an adjunct in angle-closure glaucoma patients with no cataract.

How to cite this article: Hooshmand J, Leong JCY, O’Connor J, Ang GS, Wells AP. Medium-term Anatomical Results of Laser Peripheral Iridoplasty: An Anterior Segment Optical Coherence Tomography Study. J Curr Glaucoma Pract 2017;11(3):113-119.

Associated factors of acute primary angle closure glaucoma in a sub-group of Chinese people: comparison between attack eyes and normal controls

Acute primary angle closure glaucoma (APACG) is an ophthalmic emergency that may lead to irreversible blindness. Although efforts were made to control intraocular pressure, disease progression still existed. Anterior segment optical coherence tomography (AS OCT) may provide a new insight into mechanism of APACG. In order to seek out associated factors by AS OCT, We compared anterior segment parameters between 74 APACG and 48 normal eyes. Analysis of variance, principle component analysis and logistic regression were used. APACG group had more women (75.7% vs 47.9%, p = 0.002), smaller anterior chamber (anterior chamber depth, ACD; anterior chamber area, ACA; all p = 0.001), narrower angle (AOD500, AOD750, angle opening distance at 500um and 750um; TISA500, TISA750, trabecular-iris space area at 500um and 750um; ARA500, ARA750, angle recess area at 500um and 750um; all p < 0.001), thinner iris (iris thickness at 750um, IT750; maximum of iris thickness, ITMAX; all p < 0.001), larger iris area (IA, p < 0.001) and lens vault (LV, p = 0.005). Principle component extracted were AOD500, AOD750, TISA500, TISA750, ARA500, ARA750, IA, PD (pupillary diameter), ACD, ACA and IT750. After adjusting for confounding factors, AOD750 (b = 12.40 ± 2.56, p < 0.001), IT750 (b = 10.50 ± 3.45, p = 0.002) and IA (b = −1.56 ± 0.77, p = 0.044) were significantly associated with occurrence of APACG.

Safety and Efficacy of Microinvasive Glaucoma Surgery

Microinvasive glaucoma surgery (MIGS) is emerging as a new therapeutic option for glaucoma patients who wish to reduce their medication burden and avoid the postoperative complications of conventional glaucoma filtration surgery. These devices differ in terms of their efficacy and safety profile. Schlemm's canal devices have the most favorable safety profile at the compromise of modest efficacy, while subconjunctival and suprachoroidal devices are potentially more effective at lowering the intraocular pressure at the expense of a higher rate of complications. This review consolidates the latest evidence on the efficacy and safety of the MIGS devices in clinical use and provides an overview on upcoming devices which would likely also become viable treatment options in the near future. These clinical data would assist a glaucoma surgeon in selecting the most appropriate MIGS device for each patient based on the glaucoma severity and patient expectations.

Temporal ocular coherence tomography-measured changes in anterior chamber angle and diurnal intraocular pressure after laser iridoplasty: IMPACT study

Aims

To evaluate temporal change in anterior chamber angle anatomy following argon laser peripheral iridoplasty (ALPI) in eyes with occludable angles postlaser peripheral iridotomy (LPI) compared with control eyes. Additionally, the effect on diurnal intraocular pressure (DIOP) fluctuation (maximum-minimum IOP) was investigated.

Methods

Twenty-two patients with bilateral primary angle closure/suspects with gonioscopically occludable anterior chamber angles following LPI were randomised to receive ALPI (n=11) or no further treatment (n=11). Angle opening distance (AOD), trabecular-iris angle, angle recess area and trabecular-iris space area were measured over eight sections with swept-source anterior segment optical coherence tomography and DIOP was measured pre-LPI and repeated at 3 months after ALPI (hourly measures).

Results

All angle parameters increased following ALPI. This change was maintained for 3 months in seven of the eight sections (eg, inferotemporal AOD500 increased by 0.063 mm, p=0.004 at 1 day; 0.051 mm, p=0.029 at 1 week; 0.059 mm, p=0.006 at 6 weeks and 0.056 mm, p=0.011 at 3 months). The only exception was in the inferior sector (eg, AOD500 increased by 0.041 mm, p=0.025 at 1 day and by 0.029 mm, p=0.054 at 3 months). DIOP at 3 months was significantly reduced (5.04 mm Hg; ±1.61 mm Hg) compared with controls (6.61 mm Hg; ±1.63 mm Hg). Maximum IOP was significantly greater in the non-ALPI group (1.87 mm Hg, p=0.026).

Conclusions

ALPI widened all angle sections in eyes that remained occludable post-LPI. Changes were maintained for 3 months. ALPI decreased DIOP fluctuation in the treated eyes by lowering the maximum IOP value.

Effects of phacoemulsification and intraocular lens implantation combined with ciliarotomy in the treatment of angle-closure glaucoma with cataract

The aim of the present study was to examine the effects of phacoemulsification and intraocular lens implantation combined with ciliarotomy in the treatment of angle-closure glaucoma with cataract in the elderly. A total of 68 patients were consecutively selected and divided into the control group with 33 cases (48 eyes) and the observation group with 35 cases (53 eyes). Cataract surgery combined with trabeculectomy was performed on the patients in the control group and phacoemulsification cataract extraction combined with ciliarotomy was performed on the subjects in the observation group, to compare postoperative effects and complications. Following surgery, the visual acuity of patients in the two groups significantly improved, intraocular pressure decreased, and improvement of the observation group was more evident (P<0.05). Following surgery, the depth of central anterior chamber and width of chamber angle of patients in two groups was increased, and improvement of the observation group was significantly more evident (P<0.05). Additionally, the incidence of complications, including corneal swelling, shallow of anterior chamber, fibrinous exudate in iris, and filtering bleb leaking and following cataract removal, of patients in the observation group was significantly reduced compared to the control group (P<0.05). In summary, the results of the present study show that, phacoemulsification and intraocular lens implantation combined with ciliarotomy in the treatment of angle-closure glaucoma with cataract in the elderly is a safe and effective method and should be applied in the clinic.