Three-Year Outcomes of the Paul Glaucoma Implant for Treatment of Glaucoma.

PRCIS: In our case series, the 3-year failure for Paul Glaucoma Implant (PGI) implantation was 14.6%. At 3 years postoperatively, there was a significant reduction in mean intraocular pressure (IOP) and the number of glaucoma medications used. OBJECTIVE: To determine the 3-year efficacy and safety of the PGI, a novel glaucoma tube shunt in patients with glaucoma. METHODS: Retrospective review of all patients who had undergone PGI implantation in a single tertiary institution in Singapore between May 1, 2017 and January 1, 2022. Data were extracted from electronic health records (Computerized Patient Support System 2 and Epic). The primary outcome measure was failure, defined as IOP >18 mm Hg or <6 mm Hg on 2 consecutive visits after 3 months, reoperation for IOP-related indication, explantation of implant, or loss of light perception vision. Complete success was defined as the absence of failure without medications at 36 months, and qualified success similarly, but with medications. Postoperative mean IOP, mean number of IOP-lowering medications used, and visual acuity were also assessed. RESULTS: Forty-eight eyes in 48 patients were identified. Thirty-one patients (64.6%) had primary open angle and angle closure glaucoma, and 18 (37.5%) had previous existing tube implants or trabeculectomy. At 3 years postoperatively, 7 cases (14.6%) fulfilled the criteria for failure and 36 (75%) met the criteria for complete success. The mean IOP at 36 months was 14.9 ± 4.11 mm Hg, from the mean preoperative IOP of 20.6 ± 6.13 mm Hg ( P < 0.001). The mean number of IOP-lowering medications used was reduced from 3.13 ± 0.959 preoperatively to 0.167 ± 0.476 at 36 months ( P < 0.001). The most common postoperative complication was hypotony (n = 17, 35.4%), of which the majority were self-limiting, followed by hyphema (n = 5, 10.4%) and tube exposure (n = 4, 8.3%). CONCLUSION: The PGI demonstrated sustained IOP reduction and a reduction of medication burden at 3 years postoperatively.

Glaucoma drainage implant exposure: A review of aetiology, risks and repair considerations.

In recent years, there has been a paradigm shift in glaucoma surgical procedures. Glaucoma drainage implant (GDI) surgeries are being performed much more commonly. Thus, it is important for surgeons to be cognisant of potential complications and their management. Exposure of a GDI is a well-known complication, and prompt recognition and treatment are required to prevent endophthalmitis, a potentially blinding condition. In this review, we discuss the mechanisms and risk factors for GDI exposure, highlight important considerations for repair, and discuss repair techniques, with the aim of improving patient outcomes and minimising the risk of re-exposure.

Use of anterior segment imaging and direct cyclopexy repair of cyclodialysis cleft.

We aim to describe different imaging modalities to localize cyclodialysis clefts and direct cyclopexy repair of cyclodialysis clefts. We reviewed the record of a patient with traumatic cyclodialysis cleft who underwent direct cyclopexy retrospectively. Preoperative and postoperative visual acuity and intraocular pressure (IOP) were recorded. Gonioscopy, ultrasound biomicroscopy (UBM) and 360° swept-source anterior segment optical coherence tomography (SS-ASOCT) were used to localize the cyclodialysis cleft. We concluded that UBM is the current gold standard imaging modality in localization of cyclodialysis clefts, and that SS-ASOCT is potentially useful as alternative imaging modality. Direct cyclopexy is an effective treatment for large cyclodialysis cleft with good IOP control and visual outcomes.

The Singapore Asymptomatic Narrow Angles Laser Iridotomy Study: Five-Year Results of a Randomized Controlled Trial.

PURPOSE: To examine the efficacy of laser peripheral iridotomy (LPI) in patients who received a diagnosis of primary angle-closure suspect (PACS). DESIGN: Prospective, randomized controlled trial. PARTICIPANTS: This multicenter, randomized controlled trial (ClinicalTrials.gov identifier, NCT00347178) enrolled 480 patients older than 50 years from glaucoma clinics in Singapore with bilateral asymptomatic PACS (defined as having ≥2 quadrants of appositional angle closure on gonioscopy). METHODS: Each participant underwent prophylactic LPI in 1 randomly selected eye, whereas the fellow eye served as a control. Patients were followed up yearly for 5 years. MAIN OUTCOME MEASURES: The primary outcome measure was development of primary angle closure (PAC; defined as presence of peripheral anterior synechiae, intraocular pressure [IOP] of >21 mmHg, or both or acute angle closure [AAC]) or primary angle-closure glaucoma (PACG) over 5 years. RESULTS: Of the 480 randomized participants, most were Chinese (92.7%) and were women (75.8%) with mean age of 62.8 ± 6.9 years. Eyes treated with LPI reached the end point less frequently after 5 years (n = 24 [5.0%]; incidence rate [IR], 11.65 per 1000 eye-years) compared with control eyes (n = 45 [9.4%]; IR, 21.84 per 1000 eye-years; P = 0.001). The adjusted hazard ratio (HR) for progression to PAC was 0.55 (95% confidence interval [CI], 0.37-0.83; P = 0.004) in LPI-treated eyes compared with control eyes. Older participants (per year; HR, 1.06; 95% CI, 1.03-1.10; P < 0.001) and eyes with higher baseline IOP (per millimeter of mercury; HR, 1.35; 95% CI, 1.22-1.50; P < 0.0001) were more likely to reach an end point. The number needed to treat to prevent an end point was 22 (95% CI, 12.8-57.5). CONCLUSIONS: In patients with bilateral asymptomatic PACS, eyes that underwent prophylactic LPI reached significantly fewer end points compared with control eyes over 5 years. However, the overall incidence of PAC or PACG was low.

Semi-supervised generative adversarial networks for closed-angle detection on anterior segment optical coherence tomography images: an empirical study with a small training dataset.

BACKGROUND: Semi-supervised learning algorithms can leverage an unlabeled dataset when labeling is limited or expensive to obtain. In the current study, we developed and evaluated a semi-supervised generative adversarial networks (GANs) model that detects closed-angle on anterior segment optical coherence tomography (AS-OCT) images using a small labeled dataset. METHODS: In this cross-sectional study, a semi-supervised GANs model was developed for automatic closed-angle detection training on a small labeled and large unsupervised training dataset collected from the Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong (JSIEC). The closed-angle was defined as iris-trabecular contact beyond the scleral spur in AS-OCT images. We further developed two supervised deep learning (DL) models training on the same supervised dataset and the whole dataset separately. The semi-supervised GANs model and supervised DL models' performance were compared on two independent testing datasets from JSIEC (515 images) and the Department of Ophthalmology (84 images), National University Health System, respectively. The diagnostic performance was assessed by evaluation matrices, including the accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). RESULTS: For closed-angle detection using clinician grading of AS-OCT imaging as the reference standard, the semi-supervised GANs model showed comparable performance, with AUCs of 0.97 (95% CI, 0.96-0.99) and 0.98 (95% CI, 0.94-1.00), compared with the supervised DL model (using the whole dataset) [AUCs of 0.97 (95% CI, 0.96-0.99), and 0.97 (95% CI, 0.94-1.00)]. When training on the same small supervised dataset, the semi-supervised GANs achieved performance at least as well as, if not better than, the supervised DL model [AUCs of 0.90 (95% CI: 0.84-0.96), and 0.92 (95% CI, 0.86-0.97)]. CONCLUSIONS: The semi-supervised GANs method achieves diagnostic performance at least as good as a supervised DL model when trained on small labeled datasets. Further development of semi-supervised learning methods could be useful within clinical and research settings. TRIAL REGISTRATION NUMBER: ChiCTR2000037892.

One-Year Outcomes of Micropulse Cyclophototherapy for Primary Open-angle Glaucoma.

PRECIS: In primary open-angle glaucoma (POAG), micropulse trans-scleral cyclophototherapy (MPTCP) is effective in lowering intraocular pressure (IOP), but its effects are not permanent. Hence, it can serve as a temporizing measure before definitive glaucoma surgery. PURPOSE: There is limited data on MPTCP in POAG. This is the first study that looks at MPTCP treatment specifically in POAG patients. PATIENTS AND METHODS: This is an interventional, single-institution exploratory case series with 55 eyes of 48 patients with POAG. Data was collected from clinical records, including patient demographics, clinical information, number of glaucoma medications, MPTCP laser settings, complications, and clinical outcomes. RESULTS: Patients had a mean age of 67.3±14.1 years with a preponderance of males. IOP was 24.8±1.0 mm Hg before MPTCP and decreased to 19.7±1.1, 21.9±1.1, and 21.8±1.1 mm Hg at postoperative month 3, 6, and 12 respectively. IOP remained below pretreatment levels throughout the postoperative period (P<0.05). Visual acuity and mean deviation remained stable before and after MPTCP. No eyes had complications. Number of glaucoma medications remained the same after MPTCP. Four eyes required additional oral acetazolamide at postoperative month 1 for IOP control. Seventeen eyes subsequently required further surgical intervention after 9.84 months. Maximal IOP decrease was greater when there were higher power settings, higher preoperative IOP, and better preoperative visual acuity. CONCLUSIONS AND RELEVANCE: The IOP lowering effect of MPTCP treatment in patients with POAG was found to be modest and transient with a similar medication burden, and definitive glaucoma surgery was needed in a number of patients.

Efficacy and Safety of Repeated Micropulse Transscleral Diode Cyclophotocoagulation in Advanced Glaucoma.

PRECIS: Repeat micropulse transscleral cyclophotocoagulation (MPTCP) has some benefit in lowering intraocular pressure (IOP). There was a small risk of loss of vision, prolonged hypotony, and phthisis bulbi. AIM: This study aimed to determine the efficacy and safety of repeated MPTCP for an Asian population with refractory glaucoma. METHODS: This is a retrospective case series of 43 eyes (43 patients) with severe glaucoma which underwent repeated MPTCP. Baseline parameters were taken from the visit just before the second MPTCP session. Success was defined as IOP of 6 to 21 mm Hg or ≥20% reduction in IOP without an increase in glaucoma medication from baseline, without further glaucoma reoperation, and ≤3 total MPTCP episodes. The IOP, number of IOP-lowering medications, and best-corrected visual acuity were documented preoperatively and postoperatively. Postoperative complications were also analyzed. RESULTS: The mean age±SD was 57.4±18.2 years with a mean follow-up duration of 28.9±27.5 months. Neovascular glaucoma was the most common type of glaucoma [18 eyes (41.9%)]. The success rates at postoperative years 1, 2, and 3, and the latest follow-up were 36.4%, 42.9%, 32.0%, and 39.5%, respectively. The median survival time of repeat MPTCP was 4.6 months. Compared with the preoperative mean IOP (35.2±11.0 mm Hg), the mean IOP at postoperative years 1, 2, and 3, and latest follow-up, was 27.8±13.7 mm Hg (P=0.004), 27.4±12.4 (P=0.003), 31.8±13.2 (P=0.35), and 27.1±13.8 mm Hg (P=0.002), respectively. The mean number of IOP-lowering medications was reduced from 3.3±0.9 preoperatively to 2.8±1.3 at the final follow-up (P=0.007). Postoperative complications included prolonged hypotony [3 eyes (7.0%)] and phthisis bulbi [2 eyes (4.7%)]. CONCLUSION: Repeated MPTCP is at best moderately effective in lowering IOP for eyes with advanced glaucoma.

Clinical Efficacy and Safety Outcomes of Micropulse Transscleral Diode Cyclophotocoagulation in Patients With Advanced Glaucoma.

PRECIS: Micropulse transscleral cyclophotocoagulation (MPTCP) is only moderately effective in lowering intraocular pressure (IOP) and is useful as an adjunct procedure to other glaucoma surgeries. There was a small risk of loss of vision, prolonged hypotony, and phthisis bulbi. AIM: The aim of this study was to determine the efficacy and safety of a single MPTCP treatment for an Asian population with advanced glaucoma. METHODS: This is a retrospective single-center study of 207 eyes (207 patients) with advanced glaucoma which underwent first-time MPTCP between January 1, 2008, and March 31, 2018. Success was defined as IOP of 6 to 21 mm Hg or ≥20% reduction in IOP without an increase in glaucoma medication from baseline, and without glaucoma reoperation. The IOP, best-corrected visual acuity, and number of glaucoma medications were also analyzed. RESULTS: The mean (SD) age was 64.9±16.9 years. The mean follow-up duration was 18.7±16.2 months. The rate of success at postoperative years 1 and 2 follow-up was 44.1% and 32.6%, respectively. The median survival time of MPTCP was 9.0 months and 85 (40.9%) eyes received reoperation. The mean IOP decreased from 31.5±12.0 mm Hg preoperatively to 22.1±10.3 and 23.8±11.8 mm Hg at postoperative years 1 and 2, respectively (P<0.0001). The mean number of glaucoma medications was reduced from 3.3±1.0 preoperatively to 2.6±1.1 and 2.4±1.1 at postoperative years 1 and 2, respectively (P<0.0001). Significant complications included prolonged hypotony [1 eye (0.5%)], phthisis bulbi [7 eyes (3.4%)], and best-corrected visual acuity reduction [29 eyes (13.9%)]. CONCLUSION: Single first-time MPTCP for advanced glaucoma eyes was moderately effective in lowering IOP but >50% failed by 1 year.

Treatment Outcomes Using the PAUL Glaucoma Implant to Control Intraocular Pressure in Eyes with Refractory Glaucoma.

PURPOSE: To investigate efficacy 1 year after implantation of a novel glaucoma tube shunt, the PAUL Glaucoma Implant (PGI; Advanced Ophthalmic Innovations, Singapore, Republic of Singapore), in the treatment of eyes with refractory glaucoma. DESIGN: Clinical trial. PARTICIPANTS: Glaucoma patients who are recalcitrant to maximum tolerated medical therapy and require tube shunt surgery. METHODS: Interventional cohort study involving consecutive PGIs implanted at 6 international centers between December 1, 2017, and December 1, 2018. All the participants were followed up for 1 year after surgery. MAIN OUTCOME MEASURES: The primary outcome measure was failure, defined prospectively as intraocular pressure (IOP) of more than 21 mmHg or less than 20% reduction from the preoperative baseline on 2 consecutive visits, 3 months or more after surgery; persistent late hypotony, defined as IOP of less than 6 mmHg on 2 consecutive visits after 3 months; additional glaucoma surgery; loss of light perception vision; or removal of the implant for any reason. RESULTS: Of 82 patients enrolled, 74 (74 eyes) completed 12 months of follow-up. The mean age ± standard deviation at enrollment was 62.3±14.7 years, 73.0% were men, and 36.5% had secondary glaucoma. One year after surgery, 4 patients (5.4%) fulfilled the surgical criteria for failure, 68.9% (51/74 eyes) were deemed complete successes, and 93.2% (69/74 eyes) were considered qualified successes. Compared with the medicated preoperative IOP (23.1±8.2 mmHg), the postoperative IOPs at 6 and 12 months were 13.8±4.0 mmHg and 13.2±3.3 mmHg, respectively (P < 0.001). The mean number of IOP-lowering drugs used before surgery and after 12 months of follow-up were 3.3±0.9 and 0.3±0.6, respectively (P < 0.001). Significant postoperative complications included self-limiting shallow anterior chamber (n = 11; 14.9%), hypotony requiring intervention (n = 7; 9.5%), tube shunt occlusion (n = 5; 6.8%), tube exposure (n = 3; 4.1%), and endophthalmitis with resultant loss of vision (n = 1; 1.4%). CONCLUSIONS: The PGI demonstrated comparable efficacy with other currently available implants, with almost three quarters of the enrolled patients with refractory glaucoma achieving complete surgical success after 1 year of follow-up.

Surgical Outcomes of a Second Ahmed Glaucoma Valve Implantation in Asian Eyes with Refractory Glaucoma.

RESULTS: The cumulative failure rates were 9.5%, 20.0%, 32.5%, and 46.0% at six months, one year, two years, and three years of follow-up. At final follow-up, complete success and qualified success rates were 23.8% and 33.3%, respectively; mean IOP and number of medications decreased by 5.6 mmHg (23.9%) and 1.7 mmHg (54.8%), respectively, from preoperative baseline (P < 0.01). More common postoperative complications included hypertensive phase (38.1%), corneal decompensation (23.8%), and tube exposure (14.3%). CONCLUSION: An additional AGV implant had good short and modest long-term effectiveness in reducing IOP following a failed glaucoma tube shunt in Asian eyes, with the mentioned common postoperative complications to be actively monitored and managed.

MP3 Plus: A Modified Micropulse Transscleral Cyclophototherapy Technique for the Treatment of Refractory Glaucoma.

PRéCIS:: In advanced refractory glaucoma which has failed prior MP3 laser, MP3 Plus is effective in reducing intraocular pressure (IOP) without significant complications. It is also useful as a temporizing procedure before incisional surgery. PURPOSE: To evaluate the efficacy and safety of MP3 Plus, a novel technique using modified micropulse transscleral cyclophototherapy (MPTCP) in eyes with refractory glaucoma or failed MPTCP treatment. METHODS: This is a retrospective interventional case series. In total, 32 consecutive eyes from 29 patients with uncontrolled IOPs who had previous MPTCP or refractory glaucoma underwent MP3 Plus, a modified MPTCP where additional discrete pulses are applied. The main outcome measurement was IOP at 1, 3, 6, and 12 months postprocedure, with success defined as a 20% reduction in baseline IOP, an IOP of 25 mmHg or less, and no need for further reoperation. We collected and analyzed visual acuity, number of glaucoma medications, and complications. RESULTS: The patients had an average of 1.4±0.9 glaucoma procedures before treatment, where 87.5% underwent one or more previous MPTCP with suboptimal response. Of the eyes presenting for follow-up, 51.6% (n=31), 37.0% (n=27), 35.7% (n=28), and 25.9% (n=27) achieved the primary outcome at 1, 3, 6, and 12 months, respectively. Baseline IOP was 33.7±11.6 mmHg (n=32 eyes) and posttreatment IOP at 1, 3, 6, and 12 months were 21.0±9.0 mmHg (n=31; P<0.0001), 26.2±10.8 mmHg (n=25; P<0.0001), 23.2±9.4 mmHg (n=20; P<0.05), and 24.6±9.8 mmHg (n=16; P<0.001), respectively. There was a reduction in glaucoma medications from 3.4±0.8 preoperatively to 2.8±1.2 (n=16; P<0.05) at 12 months. There were no cases of prolonged inflammation or hypotony. CONCLUSIONS: MP3 Plus is effective and safe in lowering IOP in eyes with refractory glaucoma after previous failed MPTCP.

Anticoagulation for Radiation-Induced Optic Neuropathy.

Radiation-induced optic neuropathy (RION) is a severely disabling complication of radiotherapy, without any known effective treatment. Three patients, one female and two males, aged 60, 34, and 45 years, respectively, developed progressive deterioration in visual acuity over 1 month, 8 years, and 2 months, starting 3, 12, and 9 years after radiotherapy for nasopharyngeal carcinoma. They received 70.15, 60.89, and 56.11 Gy over a period of 6-7 weeks, with fractionated doses of 2, 1.79, and 1.81 Gy, respectively. Ophthalmological examination revealed a relative afferent pupillary defect in the latter 2 patients, best-corrected visual acuity was 6/12 or better in all. Visual field charting showed a superior altitudinal field defect in the first two, and generalised visual loss in the third patient in the symptomatic eyes. Anticoagulation with heparin bridging and oral warfarin with an INR target of 2.0-3.0 was commenced within 2 months of symptom onset. All showed improvement in visual fields within 2 weeks, and remained stable for at least 2 years while on warfarin. Our encouraging findings will need to be confirmed in a randomised controlled clinical trial.

Case Series of Combined XEN Implantation and Phacoemulsification in Chinese Eyes: One-Year Outcomes.

PURPOSE: The outcome of XEN implantation in Chinese eyes has not been previously reported. The purpose of our study is to evaluate the efficacy and safety of combined cataract surgery and XEN implantation in Chinese eyes with glaucoma. METHODS: We conducted a prospective study of 31 consecutive Chinese patients who underwent combined phacoemulsification and XEN implantation at the National University Hospital (Singapore) in this study. Patients were assessed preoperatively and postoperatively on days 1 and 7, and months 1, 3, 6, and 12. The intraocular pressure (IOP), glaucoma medication use, Snellen visual acuity (VA), and complications were assessed at each visit. The Wilcoxon signed rank test for non-parametric data was used for the analysis of IOP and glaucoma medications at baseline versus 12 months after the procedure. RESULTS: The mean age of the patients was 70 ± 7.9 years and 48.4% were male. Twelve patients (38.7%) were diagnosed with primary open angle glaucoma and 19 patients (61.3%) were diagnosed with primary angle closure glaucoma. There was a significant decrease in IOP at 12 months (12.1 ± 2.6 mmHg) compared with preoperative medicated (15.6 ± 2.7 mmHg, p < 0.0001) and unmedicated IOP (22.1 ± 3.6 mmHg, p < 0.001). as well as a significant reduction in the number of glaucoma medications (1.4 ± 0.6 vs 0.1 ± 0.4, p < 0.0001). The most common complications were transient hypotony (12.9%) and ptosis (12.9%) and there were no sight-threatening intraoperative or postoperative complications. One patient required additional glaucoma surgery for uncontrolled IOP at 8 months after combined phacoemulsification and XEN implantation. CONCLUSION: Combined XEN implantation with cataract surgery was effective in lowering the IOP and the number of glaucoma medications in Chinese eyes for at least 12 months, with a favorable safety profile.

Evaluating the Laser Output of the Micropulse P3 Laser Delivery Device Following Repeated Use.

PRECIS: Repeated use of the Micropulse P3 (MP3) probe during micropulse transscleral cyclophotocoagulation is associated with an increase in laser output over time. PURPOSE: The purpose of this study was to examine the laser efficacy of the MP3 probe following repeated use. METHODS: This was an observational study carried out using Cyclo G6 Glaucoma Laser System with 6 MP3 laser delivery probes. Each probe was fired for 100 seconds, every 10 minutes until the probe was deactivated. The laser output was measured using a laser power meter. Maximum observed laser power output was also noted. RESULTS: All probes were deactivated after 90 minutes (9 cycles) of use. Mean laser output of all 6 probes was determined, and results suggested an increase in output with time. When examining the differences in total laser output for each cycle, no significant differences were observed for the first 4 cycles, but not for the remaining 5 cycles, wherein the increased laser outputs were found to be significantly different from baseline (cycle 1). CONCLUSION: Findings suggest a possible increase in laser output with repeated use, especially after 4 cycles, and clinicians need to be cautious if they intend to use the probes repeatedly.

Quantitative assessment of changes in anterior segment morphology after argon laser peripheral iridoplasty: findings from the EARL study group.

IMPORTANCE: Argon laser peripheral iridoplasty (ALPI) could be effective in widening residual angle closure following laser peripheral iridotomy (LPI). BACKGROUND: We investigated changes in angle parameters following ALPI and its safety profile in this study. DESIGN: Retrospective, observational case series. PARTICIPANTS: The records from a single centre, of 36 patients (60 eyes) who underwent ALPI, for residual angle closure following LPI, were reviewed. METHODS: We analysed anterior chamber parameters in anterior segment optical coherence tomography (ASOCT) images using customized software pre- and post-ALPI. Paired t-test was used to compare changes. MAIN OUTCOME MEASURES: ASOCT parameters analysed included angle opening distance (AOD 500 and 750), trabecular iris surface area (TISA 500 and 750), anterior chamber width (ACW), anterior chamber volume (ACV), angle recess area (ARA), anterior chamber area (ACA), anterior chamber depth (ACD) and lens vault (LV). RESULTS: There was a mean increase in AOD 500 (0.05 vs. 0.16 mm, P < 0.001), AOD 750 (0.15 vs. 0.27 mm, P < 0.001), TISA 500 (0.010 vs. 0.038 mm2 , P < 0.001), TISA 750 (0.039 vs. 0.102 mm2 , P < 0.001), ACV (89.76 vs. 102.25 mm3 , P = 0.01), ARA 500 (0.015 vs. 0.033 mm2 , P < 0.001) and ARA 750 (0.044 vs. 0.088 mm2 , P < 0.001). There was no significant change in ACW, ACD, ACA and LV. Mean intraocular pressure (IOP) decreased post-ALPI (17.2 vs. 15.7 mmHg, P = 0.002). The mean follow-up duration was 2.1 years (range 0.5-5 years). CONCLUSIONS AND RELEVANCE: ALPI results in changes to the angle morphology and lowered IOP in eyes with residual angle closure. Our findings suggest a possible role for ALPI in eyes with residual angle closure following peripheral iridotomy.

Predicting the outcome of laser peripheral iridotomy for primary angle closure suspect eyes using anterior segment optical coherence tomography.

PURPOSE: Develop an algorithm to predict the success of laser peripheral iridotomy (LPI) in primary angle closure suspect (PACS), using pretreatment anterior segment optical coherence tomography (ASOCT) scans. METHODS: A total of 69 eyes with PACS underwent LPI and time-domain ASOCT scans (temporal and nasal cuts) were performed before and after LPI. After LPI, success is defined as one or more angles changed from closed to open. All the pretreatment ASOCT scans were analysed using the Anterior Segment Analysis Program to derive anterior chamber angle (ACA) measurements. The measurements for each angle were ordered along with angle-independent measurements totalling to 42 measurements which serve as features for the prediction algorithm. Two masked glaucoma fellowship-trained ophthalmologists graded the pre-LPI ASOCT scans to determine whether LPI was likely to successful. RESULTS: There were 42 (60.9%) eyes that fulfilled the criteria for success after LPI. Iris concavity, angle recess area (750 µm) and iris concavity ratio showed the highest predictive score and were selected using correlation-based subset selection method. These features were classified into two ('successful' and 'unsuccessful') categories using a Bayes classifier. The algorithm predicted the success of LPI with 79.28% cross validation accuracy, which was superior to the predictive accuracy of the ophthalmologists (kappa 0.497 and 0.636 respectively). CONCLUSION: Using pretreatment ASOCT scans, our algorithm was superior to ophthalmologists in predicting the success of LPI for PACS eyes. This novel algorithm could aid decision making in offering LPI as a prophylaxis for PACS.