Feasibility study of sustained-release travoprost punctum plug for intraocular pressure reduction in an Asian population.

PURPOSE: To investigate the efficacy and safety of a punctum plug-based sustained drug release system for a prostaglandin analog, travoprost (OTX-TP), for intraocular pressure (IOP) reduction in an Asian population. METHODS: This is an initial feasibility, prospective, single-arm study involving 26 eyes and a bioresorbable punctum plug containing OTX-TP. An OTX-TP was placed in the vertical portion of the superior or inferior canaliculus of patients with primary open-angle glaucoma or ocular hypertension. The main outcome measure was the IOP-lowering efficacy of OTX-TP at 3 (8 am) and 10, 20, and 30 days (8 am, 10 am, and 4 pm), compared to baseline. RESULTS: A total of 26 OTX-TP were inserted for 17 subjects. The mean (standard deviation) age was 57.2 (13.8) years. At 10 days, all plugs were still present, and the IOP reduction from baseline was 6.2 (23%), 5.4 (21%), and 7.5 mmHg (28%) at 8 am, 10 am, and 4 pm, respectively. At 10 days, the mean IOP (standard error of mean) was 21.2 (1.2), 20.4 (0.8), and 19.7 (1.0) at 8 am, 10 am, and 4 pm, respectively, showing no discernible IOP trend during the course of the day. At 30 days, plug retention had declined to 42%, and the overall IOP reduction had decreased to 16%. CONCLUSION: The sustained-release OTX-TP is able to reduce IOP by 24% (day 10) and 15.6% (day 30), respectively. It is a potentially well-tolerable ocular hypotensive for glaucoma patients with a history of poor compliance.

Anterior Chamber Angle and Intraocular Pressure Changes After Phacoemulsification: A Comparison Between Eyes With Closed-angle and Open-angle Glaucoma.

PURPOSE: To compare the angle and intraocular pressure (IOP) changes after phacoemulsification between eyes with closed-angle or open-angle glaucoma. METHODS: Angle measurements using Visante AS-OCT imaging was performed for a prospective cohort of 24 subjects with closed-angle and 30 subjects with open-angle glaucoma before and 3 months after phacoemulsification. IOP measurement was measured at 6 and 12 months after surgery using Goldmann applanation tonometry as secondary outcome measures. RESULTS: Eyes with closed angles were smaller than those with open angles (mean axial length 22.88 vs. 24.11 mm, P<0.001). Mean anterior chamber depth, area, volume, AOD500, AOD750, ARA, TISA500, and TISA750 increased after phacoemulsification in all eyes regardless of preexisting angle status (all P<0.001). Increase in AOD500, AOD750, TISA500, and TISA750 were greater in eyes with open angles compared with closed angles (P=0.03, 0.04. 0.04, 0.04, respectively). Mean IOP decreased by 1.8 and 2.1 mm Hg at 6 and 12 months, respectively, after phacoemulsification for all eyes (P<0.001 for both timepoints compared with preoperative baseline). However, postoperative reduction in the mean IOP was not significantly different between eyes with closed and open angles (Mann-Whitney test P=0.32 at 6 mo and P=0.75 at 12 mo postsurgery compared with preoperative). CONCLUSIONS: Angle opening postphacoemulsification was considerable in all eyes. A similar IOP reduction after phacoemulsification was observed in all eyes regardless of angle status.

Pre-operative variables affecting final vision outcome with a critical review of ocular trauma classification for posterior open globe (zone III) injury.

PURPOSE: To identify pre-operative variables affecting the outcome of posterior open globe (zone III) injuries. Secondary objective was to re-look at the definition or landmarks for zone III injury and its clinical significance for predicting visual prognosis following open globe injury. MATERIALS AND METHODS: Retrospective review of medical records of all hospitalized patients with surgical repair of open globe injury over last 10 years at a tertiary referral eye care center in Singapore. Out of 172 eyes with open globe injury, 28 eyes (16.3%) with zone III injury was identified and reviewed further. Pre-operative visual acuity (VA) and other variables, extent of scleral wound in reference to rectus insertion, relative afferent pupillary defect (RAPD) and final vision outcome were recorded. RESULTS: Median age was 37 years with male predilection (92.9%). Mean follow-up was 12.9 months. Pre-operative VA was no light perception (NLP) in 16 (57.1%) eyes. Final VA remained NLP in 14 eyes (50.0%). The factors contributing to poor post-operative vision based on univariate regression analysis were the presence of RAPD, poor pre-operative VA, blunt trauma, extent of trauma, associated traumatic cataract, hyphema, vitreous loss and associated vitreo-retinal trauma. Further on, zone III injuries with scleral wound limited anterior to rectus insertion (6 eyes) had better vision outcome than those with injuries extending beyond rectus insertion (22 eyes). CONCLUSION: Initial VA, blunt ocular trauma, visual axis involvement, loss of light perception, presence of RAPD, traumatic cataract, hyphema, vitreous loss were the important determinants for final visual outcome in patients with zone III injury. Wound extending posterior to rectus insertion has poorer outcome as those limited anterior to rectus insertion. We suggest that there may be a need to relook at zone III injuries with reference to rectus insertion for prognostic significance, and further studies are warranted.

Assessment of circumferential angle-closure by the iris-trabecular contact index with swept-source optical coherence tomography.

PURPOSE: To evaluate the diagnostic performance of the iris-trabecular contact (ITC) index, a measure of the degree of angle-closure, using swept-source optical coherence tomography (SSOCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan) in comparison with gonioscopy. DESIGN: Prospective observational study. PARTICIPANTS: A total of 108 normal subjects and 32 subjects with angle-closure. METHODS: The SSOCT 3-dimensional angle scans, which obtain radial scans for the entire circumference of the angle, were performed under dark conditions and analyzed using customized software by a single examiner masked to the subjects' clinical details. The ITC index was calculated as a percentage of the angle that was closed on SSOCT images. First-order agreement coefficient (AC1) statistics and area under the receiver operating characteristic curve (AUC) analyses were performed for angle-closure on the basis of the ITC index in comparison with gonioscopy. MAIN OUTCOME MEASURES: Angle-closure on gonioscopy was defined as nonvisibility of posterior trabecular meshwork for at least 2 quadrants. Agreement of the ITC index with gonioscopically defined angle-closure was assessed using the AC1 statistic. RESULTS: Study subjects were predominantly Chinese (95.7%) and female (70.7%), with a mean age of 59.2 (standard deviation, 8.9) years. The median ITC index was 15.24% for gonioscopically open-angle eyes (n = 108) and 48.5% for closed-angle eyes (n = 32) (P = 0.0001). The agreement for angle-closure based on ITC index cutoffs (>35% and ≥50%) and gonioscopic angle-closure was 0.699 and 0.718, respectively. The AUC for angle-closure detection using the ITC index was 0.83 (95% confidence interval, 0.76-0.89), with an ITC index >35% having a sensitivity of 71.9% and specificity of 84.3%. CONCLUSIONS: The ITC index is a summary measure of the circumferential extent of angle-closure as imaged with SSOCT. The index had moderate agreement and good diagnostic performance for angle-closure with gonioscopy as the reference standard.

Relationship between intraocular pressure and angle configuration: an anterior segment OCT study.

PURPOSE: To assess the relationship between intraocular pressure (IOP) and anterior chamber angle (ACA) configuration as assessed by gonioscopy and anterior segment optical coherence tomography (AS-OCT). METHODS: A total of 2045 subjects aged 50 years and older, were recruited from a community clinic and underwent AS-OCT, Goldmann applanation tonometry, and gonioscopy. A quadrant was classified as closed on gonioscopy if the posterior trabecular meshwork could not be seen. A closed quadrant on AS-OCT was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. Customized software (Zhongshan Angle Assessment Program, Guangzhou, China) was used to measure AS-OCT parameters on AS-OCT scans, including anterior chamber depth, area, and volume; iris thickness (IT) and curvature; lens vault; angle opening distance; and trabecular-iris space area. IOP values were adjusted for age, sex, diabetes and hypertension status, body mass index, central corneal thickness, and presence of peripheral anterior synechiae. RESULTS: Mean age of study subjects was 63.2 ± 8.0 years, 52.6% were female, and 89.4% were Chinese. Mean IOP was 14.8 ± 2.4 mm Hg (range 826). IOP (mean ± SE) increased with number of quadrants with gonioscopic angle closure (none: 14.6 ± 0.2; one: 14.7 ± 0.3; two: 15.0 ± 0.3; three: 15.0 ± 0.3; four: 15.6 ± 0.3 mm Hg; P < 0.001), and on AS-OCT (none: 14.7 ± 0.2; one: 15.0 ± 0.2; two: 14.8 ± 0.2; three: 15.1 ± 0.3; four: 16.0 ± 0.3 mm Hg; P < 0.001). IOP also increased in association with most of the ACA quantitative parameters measured on AS-OCT images, except for IT and lens vault. CONCLUSIONS: There was an association between the extent of angle closure, as assessed on AS-OCT and gonioscopy, with increasing IOP.

Swept source optical coherence tomography measurement of the iris-trabecular contact (ITC) index: a new parameter for angle closure.

PURPOSE: To evaluate the inter- and intra-observer agreement of measurement of the iris-trabecular contact (ITC) index, a measure of the degree of angle closure, using swept source optical coherence tomography (SSOCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan). METHODS: One randomly selected eye of 60 subjects was imaged under dark room conditions. The SSOCT 3-dimensional angle scan simultaneously obtains 128 radial scans of the anterior chamber for the entire circumference of the angle. Post-imaging analysis estimated the ITC index using in-built software. For intra-observer agreement for image grading, one examiner performed the grading twice in a masked fashion and random order after a 1-week interval. A second examiner graded images to assess inter-observer agreement for image grading. For intra-observer agreement for image acquisition, a single operator imaged patients twice. For inter-observer agreement for image acquisition, a single observer graded two sets of images acquired by two different operators on the same patient. Bland-Altman plots and 95 % limits of agreement (LOA) were reported. RESULTS: Study subjects were predominantly Chinese (54/60, 90 %) and female (42/60, 70 %), with a mean age of 65.5 years. The median ITC index for eyes with open angles (31/60) and closed angles was 20 % (95 % confidence interval [CI] - 13.6, 27.8) and 49 % (95%CI - 35.5, 69.2) respectively. The mean difference (95 % LOA) for intra-observer agreement for image grading and image acquisition were -0.8 % (-8.2, 6.5) and 0.6 % (-10.9, 9.7); corresponding inter- observer agreement were 0.1 % (-10, 10.1) and -0.3 % (-11.1, 10.5) respectively. CONCLUSIONS: The inter- and intra-observer agreement of the ITC index, as a measure of extent of angle closure using SSOCT, was good.

Acceptance, attitudes, and beliefs of Singaporean Chinese toward an ocular implant for glaucoma drug delivery.

PURPOSE: We investigated patients' attitudes and perceptions toward a subconjunctival implant as a novel ocular drug delivery method for glaucoma. METHODS: We recruited 344 Chinese patients with primary open angle or angle closure glaucoma currently on topical antiglaucoma medication for a minimum of six months from specialist glaucoma clinics. Sociodemographic data, and information about patients' general and ocular health were collected. Beliefs about medicines, glaucoma, eye drops, and self-reported adherence were assessed by trained interviewers using validated questionnaires. A description about the implant was provided and patients subsequently were assessed on their understanding and acceptance. RESULTS: Of the 344 Chinese patients enrolled, 216 (62.8%) would accept the implant as a replacement for their current eye drops. Of those who accepted the implant, 99 (45.8%) were willing to accept it at similar costs, while 40 (18.5%) and 20 (9.3%) patients were willing to pay 1.5 and 2 times the cost of their present medication, respectively. Patients who accepted the implant had more severe glaucoma (P = 0.015) and felt that the implant was more helpful than eye drops (P < 0.001). Beliefs toward medicines, glaucoma, eye drops, self-reported adherence, and sociodemographic factors did not have a significant impact on the patients' decisions. CONCLUSIONS: An ocular drug implant would be an acceptable alternative to topical eye drops for subgroups of glaucoma patients.