OBJECTIVE: To compare short-term changes in corneal endothelial cells after gonioscopy-assisted transluminal trabeculotomy(GATT).
METHODS: This retrospective comparative study included 138 patients(138 eyes), and 98 of these patients underwent GATT procedure and 40 underwent SLT procedure as a control group. Changes in the corneal endothelium in patients who underwent GATT and SLT were analyzed retrospectively. Endothelial changes in the central cornea were examined using specular microscopy before and 6 months after the GATT and SLT procedure. Intraocular pressure(IOP), number of glaucoma medications, and side effects were evaluated at visits before and after two methods.
RESULTS: One hundred and thirty-eight eyes of 138 patients with a mean age of 62.9±12.7 years in the SLT group and 62.5±11.8 years in the GATT group were included in this study. Pre-procedure mean ± SD IOP was 27.7±3.6 mmHg and 27.4±5.3 mmHg (p=0.173) 2.8±0.5 and 2.9±0.8 (p=0.204) glaucoma drugs are in the SLT and GATT group, respectively. The mean corneal endothelial cell density (CECD) in the SLT group was 2433.1±581.4 cells/mm2 before the procedure and 2435.1±585 cells/mm2 6 months after the procedure, a change of 0.1±0.6% which was not statistically significant (p>0.967).The mean CECD at baseline in the GATT group was 2443.4±508.2 cells/mm2 and decreased to 2290.2±527.7 cells/mm2 6 months after this procedure, representing a cell loss of 6,2±9,1% (p<0.001).
CONCLUSIONS: GATT caused more CECD damage than SLT at the sixth month after the procedure. Considering the loss of CECD in candidates for GATT, sufficient number of endothelial cells in the central cornea is recommended.

OBJECTIVE: To compare the efficacy of gonioscopy-assisted transluminal trabeculotomy (GATT) versus micropulse transscleral diode laser cyclophotocoagulation(MP-TDLC) combined with GATT in the treatment of advanced glaucoma.
METHODS: This retrospective comparative study study included 82 patients (82 eyes) with a diagnosis of advanced glaucoma: 36 patients underwent GATT, and 46 underwent GATT + MP-TDLC. Intraocular pressure (IOP) changes in patients who underwent GATT and GATT MP-TDLC were analyzed retrospectively at regular intervals during the 6-month follow-up period.
RESULTS: For the 82 patients included in this study, the mean ± SD IOPs before the procedures were 27.2 ± 8.5 mmHg in the GATT group and 26.6 ± 6.9 mmHg in the GATT + MP-TDLC group (p = 0.866), and the numbers of glaucoma medications used were 3.41 ± 0.5 in the GATT group and 3.36 ± 0.4 in the GATT + MP-TDLC group (p = 0.605). The mean IOP after GATT was 13.6 ± 3.9 mmHg at day 1, 13.9 ± 3.7 mmHg at week 1, 14.6 ± 4.0 mmHg at month 1, 15.3 ± 4.3 mmHg at month 3, and 14.7 ± 3.3 mmHg at month 6. In the GATT + MP-TDLC group, the postoperative day 1, week 1, month 1, month 3, and month 6 IOP values were 12.4 ± 2.5, 11.8 ± 1.8, 12.1 ± 2.0, 11.8 ± 1.09, and 11.8 ± 1.5 mmHg, respectively.
CONCLUSIONS: GATT was found to be effective in the treatment of patients with advanced glaucoma, and results closer to the targeted low teens IOP values were obtained with GATT + MP-TDLC.

BACKGROUND: This retrospective study aimed to evaluate the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in Chinese patients with primary congenital glaucoma (PCG) and identify factors influencing surgical success.
METHODS: Fourteen patients (24 eyes) diagnosed with PCG who underwent gonioscopy-assisted transluminal trabeculotomy were recruited, and data on intraocular pressure (IOP), antiglaucoma medication, surgery-related complications, and additional treatments were collected during preoperative and postoperative visits. Surgical success was defined as IOP ≤ 21 mmHg and a reduction of > 30% from baseline, with (partial success) or without (complete success) antiglaucoma medication.
RESULTS: Mean preoperative IOP was 30.41 ± 6.09 mmHg. At the final visit, mean IOP reduction was 16.1 ± 9.1 mmHg (52%), and 19 of 24 eyes were topical medication-free. IOP was significantly decreased at each postoperative visit compared with baseline (P < 0.05 for all time points). Cumulative proportions of complete and partial success were 79.2% and 95.8%, respectively, at three years postsurgery. Patients without prior antiglaucoma procedures, without postoperative IOP spikes, and those undergoing complete trabeculotomy exhibited improved surgical prognosis. No permanent vision-threatening complications occurred in the 24 eyes by the end of the respective follow-ups.
CONCLUSIONS: Gonioscopy-assisted transluminal trabeculotomy emerged as a safe and effective procedure for PCG treatment, characterized by outstanding IOP reduction efficacy and high surgical success rates.

To compare the accuracy of intraocular lens (IOL) calculation formulas in patients undergoing phacoemulsification combined with gonioscopy-assisted transluminal trabeculotomy (phaco-GATT) and to determine the predictive factors for refractive errors.
Fifty-three eyes of 53 patients undergoing phaco-GATT were retrospectively reviewed. The preoperative and postoperative 3-month anterior segment (AS) parameters were measured by Scheimpflug camera. The mean prediction error (PE), mean absolute error (MAE) in the Sanders-Retzlaff-Kraft/theoretical (SRK/T), Barrett- Universal II, Hill-radial basis function (Hill-RBF) and Kane formulas were compared. The influence of biometric parameters on PE were analyzed by correlation analysis.
Postoperatively, there was a statistically significant decrease in axial length (AL) and significant enlargement in anterior chamber depth (ACD), anterior chamber angle (ACA), and anterior chamber volume (p<0.001). The mean PE using SRK/T (-0.08 diopters [D]) was more myopic than in the Barret (0.01 D) and Hill-RBF (0.01 D). The PE closest to zero was in the Kane formula (0.001 D). The Kane formula provided a lower MAE (0.30±0.28 D) than the SRK/T (0.38±0.32 D) and Barrett (0.36±0.30 D) (p<0.001). The MAE in Hill-RBF (0.32±0.28) was comparable with that in Kane (p=0.02). Preoperative AL was significantly associated with PE in all formulas except Kane. Barrett was the only formula that did not have a significant correlation between PE and postoperative ACD and ACA.
The Kane formula may provide higher predictability of the IOL power calculation than the SRK/T and Barrett-Universal II formulas in phaco-GATT surgery, which can cause significant changes in the AS and AL.

OBJECTIVE: To compare clinical outcomes between gonioscopy-assisted transluminal trabeculotomy (GATT) and trabeculectomy (TRAB) in patients with advanced-stage pseudoexfoliation glaucoma (PEXG).
METHODS: This comparative study comprised 62 patients who underwent GATT (N = 31) or TRAB (N = 31) for advanced-stage PEXG. Primary outcome was cumulative probability of surgical success at the end of 12-month follow-up. Success was determined as intraocular pressure (IOP) reduction ≥ 30% from baseline, IOP between 6 and 18 mmHg and IOP upper limits for IOP < 15 mmHg and < 12 mmHg, separately. Secondary outcomes were IOP reduction, antiglaucoma medication (AGM) use, and complications in the study.
RESULTS: Age, sex, cup/disc ratio, mean deviation, pattern standard deviation, and retinal nerve fiber layer thickness did not significantly differ between the groups (p > 0.05 for all). The probability of cumulative surgical success at the end of 12 months was similar between the two groups for IOP < 15 mmHg and < 18 mmHg but significantly higher after TRAB (92.0%) than GATT (82.5%) for IOP < 12 mmHg (log-rank test p = 0.035). Percentage of IOP reduction from baseline was similar between the groups (53.1 ± 18.6% in GATT group and 53.0 ± 16.6% in TRAB group, p = 0.98) at the end of 12 months. No significant difference in the mean number of AGM was present at the 12-month visit (1.3 ± 1.4 in GATT and 1.1 ± 1.4 in TRAB, p = 0.65).
CONCLUSIONS: At the end of 12 months, IOP reduction rate was similar between GATT and TRAB. Cumulative surgical success was higher after TRAB than GATT for IOP < 12 mmHg.

To evaluate the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with advanced glaucoma.
Records of 46 patients with advanced glaucoma were reviewed retrospectively in this single-center chart review. The main outcome measure was surgical success; intra-ocular pressure (IOP) and IOP lowering medication use were secondary outcome measures. Success was defined as an IOP of 18 mmHg or lower (criterion A) or 14 mmHg or lower (criterion B) and one of the following: IOP reduction >30% from baseline on the same or fewer medications or IOP ≤ of baseline on fewer medications as compared to baseline.
Forty-seven eyes were included in the analysis. The average mean deviation was -17.5 ± 7.2 dB (range -8.0 to -33.0). The average follow-up was 6.8 months (range 3.2-22.3). Success at 6 months was 91% for criterion A and 75% for criterion B (n = 33). Mean IOP was reduced from 19.3 ± 6 mmHg (12-40) on 3.7 ± 1.4 medications to 13.2 ± 5.8 mmHg on 1.6 ± 1.4 medications at the 6th post-operative month (P < 0.001 for both IOP and medications). At the last follow-up visit, 37 patients (78%) had an IOP of 14 mmHg or lower, and ten of these patients were unmedicated. Transient hyphema and IOP spikes were the most prevalent adverse events following surgery. Three eyes required further surgery for IOP control. None of the patients lost vision because of surgery.
GATT is a viable surgical option in cases of advanced glaucoma. Careful patient selection and attentive post-operative management are imperative.

UNASSIGNED: Minimally invasive glaucoma surgery (MIGS) is not typically used in patients with advanced-stage glaucoma. This study describes the outcomes and complications of patients with advanced open-angle glaucoma (OAG) who underwent XEN implantation with cataract surgery or gonioscopy-assisted transluminal trabeculotomy (GATT) with cataract surgery.
UNASSIGNED: This retrospective study identified patients who had undergone XEN implantation or GATT for the management of advanced OAG. Outcomes included surgical success, intraocular pressure (IOP) reduction, number of topical IOP-lowering drops, visual field mean deviation (MD), best-corrected visual acuity (BCVA), and complications. Surgical success was defined as an IOP of <14 mm Hg and a 20% reduction at 12 months without topical IOP-lowering drops (complete success) or with topical IOP-lowering drops (qualified success).
UNASSIGNED: Exactly 70 eyes were enrolled in this study, including 35 who had undergone XEN implantation and 35 who had undergone GATT. The overall surgical success rate was 74.3% (26 of 35) for eyes that underwent XEN implantation and 71.4% (25 of 35) for eyes that underwent GATT. Percent IOP reduction from baseline to 12 months postoperatively was 48% in the XEN cohort and 32% in the GATT cohort. Significant reduction in the use of topical IOP-lowering drops was demonstrated for both XEN (3.26 ± 1.15-1.23 ± 1.28) (p < 0.001) and GATT (2.46 ± 1.12-0.43 ± 0.78) (p < 0.001) cohorts at 12 months postoperatively. The only complication reported was transient hyphema, which occurred in three patients from the XEN group and four from the GATT group, and resolved spontaneously.
UNASSIGNED: Both XEN implantation and GATT may be safe and effective management options when treating patients with advanced OAG. However, larger sample sizes are required to make direct statistical comparisons between these techniques.
UNASSIGNED: In this study, XEN implantation and GATT combined with cataract surgery were each associated with favorable outcomes in patients with advanced OAG.
UNASSIGNED: Ruparelia S, Sharif M, Shoham-Hazon N. Efficacy and Safety Outcomes of XEN Implantation and Gonioscopy-assisted Transluminal Trabeculotomy for the Management of Advanced Open-angle Glaucoma. J Curr Glaucoma Pract 2023;17(2):63-67.

OBJECTIVE: To assess the safety and efficacy of combining phacoemulsification with gonioscopy-assisted transluminal trabeculotomy (GATT) compared to phacoemulsification alone in the management of primary angle closure glaucoma (PACG).
METHODS: Prospective, institutional study in which eyes requiring surgery for PACG were randomized to undergo phacoemulsification followed by GATT (phaco-GATT group) or phacoemulsification alone. Success was defined as having a final IOP of 6-20 mmHg with no subsequent glaucoma surgery or vision-threatening complications.
RESULTS: Thirty-six eyes underwent phaco-GATT with 360° angle incision and 38 eyes underwent phacoemulsification alone. IOP and glaucoma medications were significantly lower in the phaco-GATT group at 1, 3, 6, 9 and 12 months. The success rate in the phaco-GATT group was 94.4% after 12.16 ± 2.03 months, with 75% of eyes being off medications compared to 86.8% after 12.47 ± 4.27 months in the phaco group, with 42.1% off medications. (p = 0.008). Hyphema and fibrinous anterior chamber reaction were the most common complications in the phaco-GATT group and resolved with conservative treatment or required YAG capsulotomy. Although this delayed visual rehabilitation in the phaco-GATT group, it did not affect the final visual outcome with no significant difference in the final best-corrected visual acuity between both groups (p = 0.25).
CONCLUSIONS: Combining phacoemulsification with GATT in PACG yielded more favourable outcomes in terms of IOP, glaucoma medications and surgical success. Although the postoperative hyphema and fibrinous reaction may delay visual rehabilitation, GATT further lowers the IOP by breaking residual peripheral anterior synechiae and removing the dysfunctional trabeculum circumferentially, while avoiding the risks inherent in more invasive filtering procedures.

OBJECTIVE: To describe the outcomes of inferior hemisphere 180° gonioscopy-assisted transluminal trabeculotomy (hemi-GATT) in patients with moderate-severe stage primary open-angle glaucoma (POAG).
METHODS: This single center, retrospective study identified patients with POAG who had undergone combined inferior hemi-GATT with phacoemulsification. Patients with moderate-severe staged POAG were included in the study. Outcome measures included surgical success, intraocular pressure (IOP), number of topical IOP-lowering drops, best-corrected visual acuity (BCVA), visual field mean deviation (MD) and complications. Success was defined using two criteria: Criterion A (IOP <17 mmHg and >20% reduction) and Criterion B (IOP <12 mmHg and >20% reduction).
RESULTS: One hundred-twelve eyes of 112 patients were included in this study. Of these, 91 patients were followed for 24 months or greater to assess endpoint surgical success. Kaplan-Meier survival analysis for Criterion A demonstrated a 64.8% probability of success without topical IOP-lowering therapy (complete success) and a 93.4% probability of success with or without topical IOP-lowering therapy (qualified success). Probabilities of complete and qualified success using Criterion B were 26.4% and 30.8%, respectively. IOP reduction from baseline (21.9 ± 5.8 mmHg) to 24-month follow-up (13.6 ± 3.9 mmHg) was 37.9% for the overall cohort. The most common complication was transient hyphema, which occurred in 25.9% (29 of 112) of patients. All cases of hyphema resolved spontaneously.
CONCLUSIONS: Combined hemi-GATT with phacoemulsification was associated with favorable outcomes and a low complication rate in this study of patients with moderate-severe POAG. Further studies are required comparing hemi-GATT to the 360° approach.

Gonioscopy-assisted transluminal trabeculotomy (GATT) has been used as a safe and effective procedure in the treatment of open angle glaucoma. In the present report, we demonstrated successful IOP control in two uveitic glaucoma cases secondary to juvenile idiopathic arthritis (JIA) following 360° GATT. Case 1 was a 7-year-old pseudophakic male with a preoperative IOP of 38 mmHg; his IOP stabilized at 17 mmHg with two topical antiglaucoma medications over 18 months. Case 2 was a 8-year-old aphakic male with a preoperative IOP of 42 mmHg; his IOP decreased to 12 mmHg over 15 months. We observed postoperative IOP spike in case 1 which was successfully controlled conservatively. Peripheral anterior synechia formation also occured in both cases during follow-up. One should be vigilant for possible complications after GATT in such cases. As glaucoma surgery success can have a tendency to decline with time in pediatric cases with uveitis-associated glaucoma, we believe that further evidence is still required to shed more light about the benefits of GATT technique in complex cases of pediatric secondary glaucoma subtypes like JIAU-induced glaucoma.