Introduction
Glaucoma is a well-recognized optic neuropathy that can ultimately lead to blindness and its global prevalence is expected to increase in the coming decades.1,2 Reduction of intraocular pressure (IOP) remains the only established treatment that has been shown to slow glaucoma progression.3,4
The PreserFlo MicroShunt (PMS) is a minimally invasive bleb-forming surgical device composed of a highly biocompatible material known as poly(styrene-block-isobutylene-block-styrene). PMS has been available in Japan since 2022, and several studies have reported its surgical outcomes.5–13 Compared with trabeculectomy, PMS has been reported to provide comparable outcomes during the first 6 postoperative months, although its long-term IOP-lowering effect may be inferior.7 Another study found no significant difference in surgical survival between PMS and trabeculectomy but reported a tendency toward less IOP reduction with PMS.13 In a large multicenter Japanese cohort, the 1-year complete success rate was 59.4% when success was defined as an IOP of ≤12 mmHg without glaucoma medications.10
Several variations in surgical techniques for PMS implantation have been reported. In Japan and other countries, a double-step knife is used, and Sakata et al reported its clinical effects.14 Other technical modifications, including fixation of the posterior end of the PMS and intraluminal stent placement, have also been described. These modifications may improve postoperative outcomes and help prevent early postoperative hypotony.10,15,16
Another potential surgical modification is intraoperative sub-Tenon triamcinolone acetonide injection (STTA). Dias et al reported significantly better surgical outcomes when STTA was used as an adjunct to trabeculectomy.17 In contrast, Yuki et al found no significant difference in surgical survival between patients with trabeculectomy with and without STTA in eyes with secondary glaucoma (SG).18 However, to the best of our knowledge, the clinical outcomes of STTA combined with PMS implantation have not yet been evaluated. In particular, it remains unclear whether this approach is associated with favorable IOP control, the need for postoperative interventions such as bleb needling, or the occurrence of postoperative hypotony.
Therefore, the present study aimed to investigate the 1-year surgical outcomes, postoperative interventions, and adverse events following PMS implantation with intraoperative STTA. These findings may provide clinically relevant information for perioperative management and patient counseling after PMS implantation.
Methods
Study Design
This was a two-center retrospective study that included all consecutive cases performed by two surgeons (Y.T. and S.S.) at the Japan Community Healthcare Organization Kanitounou Hospital and Japan Community Healthcare Organization Chukyo Hospital between December 2023 and May 2025. No specific exclusion criteria were applied. Among patients who underwent bilateral surgery, only the eye that was operated on first was included in the analysis.
The study was approved by the ethics committee of Japan Community Healthcare Organization Kanitounou Hospital (approval no. 26,052,006) and conducted in accordance with the tenets of the Declaration of Helsinki.
The following data were extracted from the medical records: age, sex, glaucoma subtype, preoperative IOP, medication score, mean deviation (MD), best-corrected visual acuity (BCVA), postoperative IOP, and medication score at 1, 3, 6, 9, and 12 months; BCVA at 12 months; and the occurrence of adverse events, additional postoperative procedures, and reoperations. IOP was measured using Goldmann applanation tonometry (GAT). Medication scores were calculated based on the number of active glaucoma medication classes rather than the number of eye-drop bottles.
Each single-agent eyedrop was assigned one point, whereas each fixed-combination eyedrop was assigned two points. Oral acetazolamide was scored separately according to the daily number of tablets, allowing half-point increments. The MD values were obtained using either the Humphrey Field Analyzer 24–2 test or the imo vifa 24plus (1–2) test.
Corneal endothelial cell density was excluded from the analysis because the measurement devices and protocols differed between centers and examination time points.
Surgical Procedure
Both the surgeons performed the same surgical procedures. After creating a 4–6 mm limbal conjunctival incision at the intended implantation site, the Tenon’s capsule was dissected. Mitomycin C (0.4 mg/mL) was applied for 5 min using tied surgical sponges.
A pilot scleral tract was created approximately 3 mm posterior to the limbus, and the PMS was inserted. After confirming aqueous humor flow through the device, Tenon’s capsule was sutured to the limbus using 10–0 polyglactin sutures. Both ends of the conjunctival incision were secured to the limbus using 10–0 polyglactin sutures.
Immediately before final conjunctival closure, a blunt cannula was inserted at the limbus, and 20 mg of triamcinolone acetonide (0.5 mL, 40 mg/mL; Bristol Pharmaceutical, Tokyo, Japan) was injected into the sub-Tenon space. Subsequently, the conjunctiva was closed using a continuous limbal suture to complete the procedure. At the surgeon’s discretion, the posterior end of the PMS was fixed to the sclera and/or a 10–0 nylon intraluminal stent was placed within the PMS.
For postoperative management, topical antibiotics were discontinued within 1 month of surgery. Betamethasone and bromfenac eye drops were administered four and two times daily, respectively, for approximately 3 months in eyes with primary open-angle glaucoma (POAG) or pseudoexfoliation glaucoma (PEG). In eyes with SG, these medications were continued for >3 months at the surgeon’s discretion.
Surgical Success Criteria
Assessment of surgical success based on the IOP level and percentage of IOP reduction was initiated 3 months postoperatively. Complete success (CS) was defined as an IOP of 6–12 mmHg measured using GAT, together with an IOP reduction of at least 20% from baseline, without the use of glaucoma medications and without meeting any of the failure criteria described below. Qualified success (QS) was defined using the same criteria as CS, except that the initiation or resumption of glaucoma medication was permitted.
As a secondary outcome, needling-free CS was evaluated using the same criteria as CS, except that the first postoperative needling procedure was considered a failure. The exact date of the first needling was the date of the event.
Failure based on the IOP criteria was defined as failure to meet the success criteria at two consecutive scheduled visits occurring 3 months or more after surgery because the IOP was >12 mmHg or <6 mmHg, or because the IOP reduction from baseline was <20%. The failure date was defined as the date of the first two consecutive visits on which the criteria were not met. If therapeutic intervention was required for clinical findings related to hypotony, the date of intervention was considered the failure date, regardless of the IOP value or the number of consecutive visits.
Loss of light perception; repositioning, reinsertion, or removal of the PMS; open bleb revision; additional glaucoma surgery; or additional intraocular surgery for serious surgery-related ocular complications were also considered failures. When reoperation was required, the date of the reoperation was defined as the date of failure. However, if a serious surgery-related complication was diagnosed before reoperation, the date of diagnosis was used as the failure date.
Needlings were permitted for the primary analysis.
Complications
Numerical hypotony was defined as an IOP of ≤5 mmHg measured by GAT. Hypotony present at the 1-month visit was defined as hypotony observed at 1 month postoperatively that recovered to an IOP of ≥6 mmHg by the 3-month visit and did not subsequently recur. Persistent hypotony was defined as an IOP of ≤5 mmHg at two or more consecutive scheduled visits from 1 month after surgery onward.
Delayed-onset hypotony was defined as hypotony that was absent at the 1-month visit but first occurred at 3 months or later and persisted for at least two consecutive scheduled visits.
Although IOP was monitored clinically during the first postoperative month, the timing of examinations and the measurement methods were not standardized because of the retrospective study design, and some IOP measurements were obtained using devices other than GAT. Therefore, early postoperative IOP values were not included in the standardized quantitative analysis, and the incidence of early numerical hypotony was not evaluated. However, a shallow anterior chamber, choroidal detachment, hypotony maculopathy, and any intervention or reoperation for hypotony that occurred within the first postoperative month were separately identified from the medical records as hypotony-related adverse events.
Statistical Analysis
Surgical outcomes were assessed using Kaplan–Meier survival analysis. For complete success, survival curves were compared among the glaucoma subtypes using the log-rank test. Cox proportional hazards regression analysis was performed to evaluate whether age, glaucoma subtype (classified as PEG vs other types), preoperative IOP, and preoperative medication scores were associated with surgical failure.
IOP and medication scores were compared across preoperative and postoperative time points using the Friedman test. When the Friedman test indicated a significant difference, post hoc comparisons between the preoperative value and each postoperative time point were performed using the Wilcoxon signed-rank test. Bonferroni correction was applied for the five post hoc comparisons, and P < 0.01 was considered statistically significant for these comparisons.
In addition, IOP measured immediately before and after needling was compared using the Wilcoxon signed-rank test. For eyes that underwent multiple needling procedures, only the first procedure was included in the analysis. Except for the comparison of IOP and medication scores, statistical significance was defined as P<0.05.
All statistical analyses were performed using IBM SPSS Statistics (version 29.0; IBM Corp., Armonk, NY., USA).
Results
A total of 117 eyes of 107 patients were included in the study. As 10 patients underwent bilateral surgery, only the first operated eye was included, resulting in 107 eyes from 107 patients for the analysis. Follow-up data were available for 106 eyes (99.1%) at 1 month, 106 eyes (99.1%) at 3 months, 105 eyes (98.1%) at 6 months, 97 eyes (90.5%) at 9 months, and 99 eyes (92.5%) at 12 months.
Baseline clinical characteristics are summarized in Table 1 as median and interquartile range (IQRs). The median age was 76.0 years (IQR, 67–82 years). The cohort included 60 men and 47 women with 43 right and 64 left eyes, respectively.
The median preoperative intraocular pressure was 22.0 mmHg (IQR, 17–28), the median preoperative medication score was 5.0 (IQR, 4.0–5.0), the median preoperative logMAR visual acuity was 0.3 (IQR, 0.0–0.7), and the median mean deviation was −15.56 dB (IQR, −21.18 to −8.29).Table 1Clinical Characteristics of the Patients in This StudyCharacteristicsTotal (n = 107)Age (IQR)76.0 (67, 82)Sex (Male/ Female)60, 47Side (R/ L)43, 64Glaucoma type (POAG/PEG/SG)61, 31, 15Preoperative1 Corrected visual acuity (logMAR) (IQR)0.3 (0.0, 0.7)Mean deviation (dB) (IQR)−15.56 (−21.18, −8.29)Implantation site(superior/superotemporal/superonasal/inferotemporal)1, 79, 26, 1Intraoperative procedures(posterior-end fixation/intraluminal stent placement)12, 7Previous glaucoma surgery(outflow pathway surgery/filtering surgery)20, 19Lens (IOL/phakia)88, 19Preoperative IOP (mmHg) (IQR)22.0 (17, 28)Preoperative medication score (IQR)5.0 (4–5)Abbreviations: IQR, inter quartile range; IOL, IOP, intraocular pressure; POAG, primary open-angle glaucoma; PEG, pseudoexfoliation glaucoma; SG, secondary glaucoma; R, right; L, left.
All the eyes underwent standalone PMS implantation. Nineteen eyes were phakic and 88 were pseudophakic. The implantation site was superior in one eye, superotemporal in 79 eyes, superonasal in 26 eyes, and inferotemporal in one eye.
The glaucoma subtypes included POAG in 61 eyes, PEG in 31 eyes, and SG in 15 eyes, comprising 10 eyes with uveitic glaucoma and five eyes with glaucoma after vitrectomy. Fixation of the posterior end of the PMS was performed in 12 eyes and an intraluminal stent was placed in seven eyes. Among the seven eyes with intraluminal stent placement, the stent remained in place in two eyes, was removed at 2 weeks postoperatively in three eyes, and was removed at 1 month postoperatively in two eyes.
Twenty eyes had a history of outflow pathway surgery, and 19 eyes had undergone filtering surgery.
Changes in postoperative IOP and medication scores are shown in Figure 1. The median postoperative IOP was 6 mmHg (IQR, 5–8) at 1 month, 7.0 mmHg (IQR, 5–9) at 3 months, 8.0 mmHg (IQR, 6–10) at 6 months, 9.0 mmHg (IQR, 7–11) at 9 months, and 9.0 mmHg (IQR, 6–12) at 12 months. The IOP was significantly lower than the preoperative value at all postoperative time points (P<0.001).
The median medication score was 0.0 (IQR, 0.0–0.0) at 1, 3, 6, 9, and 12 months and was also significantly lower than the preoperative value at all time points (all P<0.001). The median logMAR visual acuity at 12 months was 0.3 (IQR, 0.0–0.8), with no significant change from baseline (P=0.178).Figure 1Changes in postoperative intraocular pressure and medication score. Changes in intraocular pressure and medication score are shown, with the solid line representing intraocular pressure and the dashed line representing medication score.
Both intraocular pressure and medication score were significantly lower than their respective preoperative values at all postoperative time points (all P<0.001).A line graph and table showing intraocular pressure and medication score from preoperative to 12M.A line graph with two lines and a data table. Horizontal axis: preoperative, 1M, 3M, 6M, 9M, 12M. Left vertical axis: mmHg (0-25).
Right vertical axis: score (0-5). Solid line (intraocular pressure): preoperative ~22, 1M ~6, 3M ~7, 6M ~8, 9M ~9, 12M ~9. Dashed line (medication score): preoperative ~5, 1M 0, 3M 0, 6M 0, 9M 0, 12M slightly above 0.
Table columns: Preoperative n equal 107; 1M n equal 106; 3M n equal 106; 6M n equal 105; 9M n equal 97; 12M n equal 99. IOP mmHg IQR: 22.0 (17, 28); 6.0 (5, 8); 7.0 (5, 9); 8.0 (6, 10); 9.0 (7, 11); 9.0 (6, 12). Medication score IQR: 5.0 (4.0, 5.0); 0.0 (0, 0); 0.0 (0, 0); 0.0 (0, 0); 0.0 (0, 0); 0.0 (0, 0).
The Kaplan–Meier survival curves at 1 year are shown in Figure 2. The estimated 12-month complete and qualified success rates were 83.1% and 85.0%, respectively. For complete success, 25 of 31 eyes with PEG remained successful (80.6%), compared to 53 of 61 eyes with POAG (86.9%) and 11 of 15 eyes with SG (73.3%).
Survival did not differ significantly among glaucoma subtypes according to the log-rank test (P = 0.429). The results of the Cox proportional hazards regression analysis are presented in Table 2. None of the evaluated variables were significantly associated with surgical failure.Figure 2Kaplan–Meier survival curves.
Twelve months postoperatively, the estimated survival rates are 83.1% for complete success (solid line), 85.0% for qualified success (dashed line), and 67.7% for needling-free complete success (dotted line). The numbers of eyes at risk at 0, 3, 6, 9, and 12 months are shown below the curves.Kaplan Meier graph of survival probability post-surgery: complete, qualified and needling-free success.A line graph with three Kaplan Meier curves and a number at risk table below. Vertical axis label, Cumulative survival probability, with range 0.0 to 1.0.
Horizontal axis label, Time after surgery (months), with range 0 to 12 and tick labels 0, 3, 6, 9, 12. Legend entries: Complete success (CS) shown as a solid line, Qualified success (QS) shown as a dashed line, Needling free CS shown as a dotted line. Number at risk table header, No. at risk and Months with columns 0, 3, 6, 9, 12.
Complete success (CS): 0 months 107, 3 months 102, 6 months 96, 9 months 86, 12 months 84. Qualified success (QS): 0 months 107, 3 months 103, 6 months 97, 9 months 87, 12 months 85. Needling free CS: 0 months 107, 3 months 101, 6 months 91, 9 months 81, 12 months 74.Table 2Results of Cox Proportional Hazards Regression AnalysisHazard Ratio (HR) (95%CI)P valueAge1.015 (0.971, 1.061)0.504Preoperative IOP0.992 (0.938, 1.049)0.783Preoperative medication score0.996 (0.730, 1.360)0.982Glaucoma subtype (PEG vs non-PEG)1.145 (0.388, 3.376)0.807Abbreviations: IOP, intraocular pressure; PEG, pseudoexfoliation glaucoma.
Postoperative needling was performed in 18 eyes (16.8%), including 4 eyes (3.7%) that required multiple needling procedures. The median time to the first needling procedure was 8.5 months (IQR, 4.8–11.3). Needling was performed within 3 months in 3 eyes, 4–6 months in 4 eyes, 7–9 months in 3 eyes, and 10–12 months in 8 eyes.
Median IOP decreased significantly from 16.0 mmHg (IQR, 13.0–18.25) immediately before needling to 10.0 mmHg (IQR, 9.0–12.0) immediately after needling (P<0.001). The estimated 12-month complete needling-free success rate was 67.7%. Of the 18 eyes that underwent needling, 16 (88.9%) met the criteria for complete success at the final available assessment within 12 months.
The adverse events are summarized in Table 3. Hyphema occurred in 26 eyes (24.3%), choroidal detachment in 12 eyes (11.2%), shallow anterior chamber in nine eyes (8.4%), and hypotony maculopathy in four eyes (3.7%). Hypotony was present at the 1-month visit in 37 eyes (34.6%), of which 25 (23.4%) developed persistent hypotony.
Delayed-onset hypotony occurred in two eyes (1.9%). One eye underwent intraluminal stent placement at 1 month because of a shallow anterior chamber. The other eye underwent PMS repositioning and intraluminal stent placement at 4 months because of persistent choroidal detachment and hypotony, together with a suspected corneal endothelial compromise.
In the remaining patients, hypotony, choroidal detachment, hypotony maculopathy, and shallow anterior chamber resolved spontaneously with observation or conservative treatment, and a decrease in visual acuity of two or more lines occurred in 18 eyes (16.8%). One eye (0.9%) developed suprachoroidal hemorrhage on the night of surgery and resulted in permanent loss of vision despite multiple surgical interventions. No adverse events such as PMS exposure or obstruction were observed.
One eye underwent open bleb revision at 7 months because of inadequate IOP control.Table 3Adverse Events and Additional Surgical Procedures or InterventionsNumber of eyes (%)Hyphema26 (24.3)Choroidal detachment12 (11.2)Suprachoroidal hemorrhage1 (0.9)Shallow anterior chamber9 (8.4)Hypotony maculopathy4 (3.7)hypotony present at the 1-month visit37 (34.6)Persistent hypotony25 (23.4)Delayed-onset hypotony2 (1.9)Decrease in visual acuity of two or more lines18 (16.8)Bleb revision1 (0.9)Needling18 (16.8)Underwent intraluminal stent placement2 (1.9)
Discussion
To the best of our knowledge, this study is the first to report the 1-year outcomes of PMS implantation combined with intraoperative STTA. The median IOP at 12 months was 9.0 mmHg (IQR, 6–12). In addition, previous studies using a success criterion of an IOP of ≤12 mmHg together with an IOP reduction of at least 20% reported 1-year success rates of 53.9%–59.4%.10,13 In the present study, the corresponding 1-year complete success rate was 83.1%, which is higher than that reported previously.
The estimated success rate was higher than that reported in previous Japanese cohorts.10,13 Differences in baseline IOP, case mix, surgical protocols, postoperative interventions, and outcome definitions precluded direct comparisons. The favorable outcomes observed in this cohort may be related to the largely standardized surgical protocol incorporating intraoperative sub-tenon triamcinolone; however, the contribution of triamcinolone itself cannot be isolated because no control group without triamcinolone was available.
However, the MMC protocol differed between the present and previous studies.10,13 In study,13 the same MMC concentration was used, but the application time was 3 min, which was shorter than the 5-minute exposure used in our study and may have influenced the outcomes. The study examined whether an MMC application time of 3 min or 5 min affected surgical success.10 Longer MMC exposure was associated with improved outcomes under the less stringent IOP criteria, although no statistically significant association was detected under the ≤12-mmHg criterion. Therefore, although the MMC application time differed between the present study and previous reports,10,13 its influence on the observed differences in the outcomes may have been limited.
Previous studies on filtering surgery with adjunctive STTA have included a study of non-inflammatory glaucoma and another of SG.17,18 In study,17 trabeculectomy outcomes were compared between eyes with and without adjunctive STTA in patients with noninflammatory glaucoma, including POAG. The 12-month survival rate was significantly higher in the STTA group than in the non-STTA group (87.2% vs 66.7%, respectively). In the present study, the survival rate was highest in eyes with POAG.
These findings indicate that favorable outcomes can be achieved using a standardized protocol incorporating STTA. However, they do not establish that STTA itself improves surgical success. Therefore, prospective comparative studies evaluating surgeries with and without STTA are warranted.
In contrast, this study found no significant difference in survival after trabeculectomy for SG between eyes treated with and without STTA (65.4% vs 63.0%),18 suggesting that STTA did not improve outcomes in this population. In the present study, although the difference between the glaucoma subtypes was not statistically significant, the survival rate was lower in eyes with SG than in those with POAG or PEG. However, the patient populations differed between the studies.
In a previous study,18 neovascular glaucoma accounted for approximately half of the SG cases, whereas inflammatory glaucoma accounted for only approximately 15%. In contrast, the SG group in the present study exclusively consisted of patients with uveitic glaucoma and glaucoma after vitrectomy. These differences in the case mix may have influenced the outcomes.
Further studies with larger sample sizes are needed to enable more detailed comparisons of glaucoma subtypes.
In the present study, needling was performed in 18 eyes (16.8%), most of which met the criteria for complete success. The approximately 15-percentage-point difference between the needling-free complete success rate and the complete success rate suggests that needling is required in some eyes to maintain a high overall success rate. In addition, IOP decreased significantly immediately after needling, suggesting that needling may have contributed to postoperative IOP control in some eyes; however, its long-term effect could not be determined from the present retrospective analysis.
In a previous study,10 needling was performed in 9.6% of the eyes, which was lower than the rate observed in the present study. However, because that study did not report whether eyes that underwent needling ultimately achieved surgical success, a direct comparison is difficult. Nevertheless, the higher needling rate in the present study may have contributed to the more favorable survival rate compared with previous reports.10 Further studies using standardized indications and timing of needling are required.
No significant baseline predictors of failure were identified in the present cohort. However, these findings should not be interpreted as evidence that these factors have no prognostic relevance. The limited number of failure events may have reduced the statistical power, and residual confounding from unmeasured clinical and surgical factors remains possible.
The relatively standardized surgical and postoperative protocols may also have reduced the variability in outcomes across patient subgroups.
Regarding adverse events, hyphema has been reported in 20–35% of eyes in previous studies,10,13,14 which is comparable to the incidence observed in the present study. Previous reports have described numerical hypotony in 14.7%–33.4% of eyes,10,13 choroidal detachment in 14.7%–17.8%,10,13 and a shallow anterior chamber in 3.0%–10.3%,10,13 all of which are similar to the frequencies observed in our cohort. In the present study, however, persistent and delayed-onset hypotony occurred in 23.4% and 1.9% of the eyes, respectively.
One eye with persistent hypotony required intraluminal stent placement due to worsening choroidal detachment, whereas the remaining cases either resolved spontaneously or involved hypotony without associated maculopathy or choroidal detachment. Because previous studies did not classify hypotony according to its duration, a direct comparison was difficult. Although adjunctive STTA may be associated with a greater likelihood of prolonged hypotony, this could not be determined in the present uncontrolled study, and comparative studies are required.
Suprachoroidal hemorrhage occurred in one eye, resulted in permanent loss of vision. Previous reports have described suprachoroidal hemorrhages after PMS implantation.19,20 In the present case, the event occurred after nose blowing on the night of the surgery, suggesting that a Valsalva-related increase in venous pressure in the setting of early postoperative hypotony may have contributed. However, causality cannot be established from a single case.
A decrease in visual acuity of two or more lines was observed in 18 eyes (16.8%). One of these eyes became blind because of suprachoroidal hemorrhage. Cataract progression may have contributed to the visual deterioration, as six of the affected eyes were phakic.
However, one of these eyes also developed hypotony maculopathy, which may have contributed to the visual decline. Additionally, because the present cohort included many eyes with advanced glaucoma, further glaucomatous progression may have been responsible for visual deterioration in some cases. However, postoperative cataract status and visual field outcomes were not systematically collected; therefore, the causes of visual decline could not be conclusively determined and require further investigation.
Several cases of corneal endothelial cell loss following PMS implantation have been reported.21–23 A previous study reported a reduction in corneal endothelial cell density of more than 20% in approximately 10% of the eyes.13 In the present study, one eye underwent PMS repositioning because of suspected corneal endothelial cell loss. However, corneal endothelial cell density was excluded from the analysis because the measurement devices and protocols differed between centers and examination time points. Further studies using standardized measurement methods are required to evaluate the potential effects of adjunctive STTA on the corneal endothelium.
This study had some limitations that should be acknowledged. First, it was retrospective and included only eyes treated with adjunctive STTA; therefore, no comparison was possible with eyes that underwent PMS implantation without STTA. Prospective comparative studies are required to evaluate the efficacy and safety of adjunctive STTA.
Second, fixation of the posterior end of the PMS and intraluminal stent placement were performed in a small number of eyes, precluding the assessment of their effects on surgical outcomes. Third, the risk factor analysis was exploratory and based on approximately 20 failure events; therefore, the model had limited precision and may have been underpowered to detect modest associations. However, further studies are required to confirm these findings.
Fourth, because needling was performed at or around the 12-month visit in some eyes, the post-needling follow-up was limited to a part of the cohort. Therefore, long-term follow-up is required to assess the durability of outcomes after needling. Finally, objective assessments of anterior chamber inflammation using a laser flare cell meter and filtering bleb morphology using anterior segment OCT were not performed in this study; therefore, the potential anti-inflammatory and bleb-modulating effects of STTA could not be directly evaluated.
Despite these limitations, the results suggest that PMS implantation with intraoperative STTA may be an effective surgical protocol associated with substantial IOP reduction and a high 1-year success rate; however, clinicians should remain aware of postoperative hypotony and the potential need for bleb needling.
Conclusion
PMS implantation using a standardized protocol incorporating intraoperative STTA was associated with substantial IOP and medication reductions, and a favorable 12-month success rate. Prolonged numerical hypotony was observed in a notable proportion of the eyes, although most cases resolved without surgical intervention. Controlled studies are required to determine the specific efficacy and safety of sub-Tenon triamcinolone.