Ab Externo Choroidal Fluid Drainage, Pars Plana Vitrectomy, and Endotamponade for the Management of Persistent Hypotony following Glaucoma Surgery.

Background: Persistent severe serous choroidal detachment is a rare complication after glaucoma surgery. Surgical treatment with choroidal fluid drainage through a scleral incision is an option in these cases. Combining this procedure with pars plana vitrectomy and gas endotamponade has potential advantages. In the following, the perioperative course of this surgical option in a small cohort will be presented. Methods: This is a retrospective cohort study of the postoperative course of ab externo drainage of persistent serous choroidal detachment (≥4 weeks) in combination with pars plana vitrectomy and gas endotamponade in six eyes of six patients after exhausting all conservative treatment options. Inclusion criterion was persistent hypotony with severe serous choroidal detachment after intraocular pressure (IOP) lowering surgery due to medically uncontrolled glaucoma. Eyes were evaluated according to resolution of choroidal detachment, change in IOP and visual acuity (VA), postdrainage complications, and need for further surgeries. Results: Before surgery, all patients presented with flat anterior chamber, decreased vision, and persistent choroidal detachment. The surgery itself was uneventful, but due to the complexity of the cases, tailoring the procedure to each patient's needs was required. Complete resolution of choroidal effusion was achieved by one month in 5 eyes and in 1 eye by month 3. There was an increase in average IOP from 5 (±2.1) mmHg before surgery to 11.3 (±3.7) mmHg and in VA from 1.7 (±0.8) to 1.2 (±0.6) logMAR. Five out of six patients required additional surgery, mainly to further increase the IOP even though choroidal detachment had already resolved. Conclusion: Ab externo choroidal fluid drainage combined with pars plana vitrectomy and gas endotamponade seems to be an effective and safe treatment option in persistent ocular hypotony. Although repeated surgeries might be necessary, large-scale prospective studies must be undertaken to provide corroborative evidence.

Effect of trabeculectomy on the rate of progression of visual field damage.

OBJECTIVES: This study quantifies the effect of trabeculectomy on the rate of progression (RoP) of visual field (VF) damage utilising pre- and post-operative visual function as the outcome instead of surrogate outcomes of success. METHODS: Clinical and VF data from 199 sequential patients who underwent trabeculectomy between 2015 and 2016 were extracted from the network of sites of Moorfields Eye Hospital NHS Foundation Trust. Of these, we analysed 80 eyes of 74 patients who met our inclusion criteria of at least three reliable VFs before and after surgery (false positive rate <15%). The change in mean RoP (dB/year) was tested using point-wise sensitivity values through a mixed effect model with random effects on both intercepts and slopes. A broken-stick regression of sensitivity over time, with a breakpoint at the day of surgery, modelled the individual change in RoP. RESULTS: We analysed 10 [9,12] VFs per subject (Median [Interquartile Range]). At surgery, the age was 67 [57, 72] years, mean deviation was -10.84 [-14.7, -5.6] dB and the IOP was 18 [15, 20] mmHg. One year after surgery, the IOP was 10 [8,13] mmHg (p = 0.002). Mean RoP before surgery was -0.94 [-1.20, -0.69] dB/year (Mean [95% credible intervals]) and it was slowed down by 0.62 [0.26, 0.97] dB/year (p < 0.001) after surgery. CONCLUSIONS: Trabeculectomy leads to a significant reduction in the RoP of VF loss postoperatively.

Changes of Neuroretinal Rim and Retinal Nerve Fiber Layer Thickness Assessed by Optical Coherence Tomography After Filtration Surgery in Glaucomatous Eyes.

PURPOSE: Lowering the intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG) with filtration surgery can induce morphological changes to the bulbus and structures of the retina. In this study, we have evaluated changes of Bruch's membrane-based parameters and retinal nerve fiber layer (RNFL) derived by spectral-domain optical coherence tomography (SD-OCT) in eyes that have undergone glaucoma filtration surgery. PATIENTS AND METHODS: SD-OCT imaging of the optic nerve head (ONH) and of the RNFL was performed in 54 eyes of 54 patients with medically uncontrolled POAG before and after IOP-lowering surgery (trabeculectomy or deep sclerectomy). The ONH parameter minimum rim width (MRW) and the size of the Bruch's membrane opening (BMO-Area) were derived from 24 radial B-scans centered on the ONH. RESULTS: The average preoperative IOP was 23.1 ± 7.5 mmHg. One month postoperatively, the average IOP decreased to 12.1 ± 4.6 mmHg (p < 0.01), which caused a significant increase in the thickness of neuroretinal rim. There was no significant change in the automatically detected BMO-Area (p = 0.32). The pressure-related increase in MRW correlated well with the postoperative IOP and cup-to-disc ratio (CDR). In regression analysis, the alteration in thickness of the neuroretinal rim could be well predicted in a model including CDR, change of IOP and mean deviation (MD) (R2 = 0.414, p < 0.001). RNFL showed a significant increase as well. CONCLUSION: IOP-lowering surgery in patients with medically uncontrolled POAG causes an increased thickness of the SD-OCT derived ONH parameters. The changes of the RNFL after surgery showed no significant correlations with IOP changes. In contrast to this, highly significant correlations of MRW values with the IOP could be observed. The BMO-Area remained completely stable A preferred use of RNFL for follow-up should be discussed.