Possible bidirectional flow of aqueous fluid after Baerveldt glaucoma implant surgery

Three-year outcome of sulcus fixation of Baerveldt glaucoma implant surgery

PURPOSE

The purpose of this study was to evaluate the 3-year surgical outcome of the sulcus fixation of Baerveldt glaucoma implant (BGI), focusing on corneal damage.

METHODS

This prospective observational study included 37 patients who underwent a median of two previous glaucoma surgeries and sulcus fixation of BGI for the first time. Each patient's intraocular pressure (IOP), glaucoma drug score, corneal endothelial cell density (ECD), and logMAR-converted best-corrected visual acuity (VA) were measured preoperatively and postoperatively until 36 months after surgery. Complete success was defined as reduced IOP (5-21 mmHg and >20% rate), without corneal damage (postoperative development of decompensation, unmeasurable ECD, or reduction in ECD of >20%), without loss of light perception, and without additional surgery requirement. Qualified success was defined by excluding the corneal criteria from complete success.

RESULTS

A total of 51% (19/37) patients experienced complete treatment success, whereas 86% (32/37) had qualified success. The median IOP (glaucoma drug score) decreased from 26 mmHg (5) to 15 mmHg (2) at three years postoperatively. The median postoperative ECD (reduction rate) decreased from 1838 cells/cm² preoperatively to 1587 cells/mm² (14%) at one year, 1358 cells/mm² (26%) at two years, and 1228 cells/mm² (33%) at three years postoperatively. One month after surgery, the VA was significantly reduced from preoperative values but did not decline after that.

CONCLUSION

Sulcus fixation of BGI was effective for IOP reduction. However, ECD decreased over time.

Comparison of surgical outcomes of trabeculectomy, Ahmed shunt, and Baerveldt shunt in uveitic glaucoma

Background

Uveitis is defined as a collection of syndromes involving intraocular inflammation which can lead to pain, tissue damage, and vision loss. Ophthalmic surgery in uveitis patients can be challenging due to inflammation-induced fibrosis and scarring. Trabeculectomy and implantation of glaucoma drainage devices (aqueous shunts) have been used in surgical management of uveitic glaucoma, however there is a paucity of literature examining the comparative results of these entities in this unique setting. The purpose of this retrospective comparative study is to compare clinical outcomes of trabeculectomy with MMC, Ahmed shunt, and Baerveldt shunt surgery specifically in uveitic glaucoma.

Results

Median IOP, IOP reduction, glaucoma medication use, and visual acuity at 6- and 12-month follow-up were similar across groups. Postoperative hypotony rate was significantly different across trabeculectomy (53%), Baerveldt (24%), and Ahmed (18%) groups (p = 0.027); other complication rates were similar. Baerveldt eyes had a lower failure rate compared to trabeculectomy (p = 0.0054) and Ahmed (p = 0.0008) eyes.

Conclusions

While there was no difference in IOP reduction between trabeculectomy, Ahmed, and Baerveldt, Baerveldt eyes had the lowest failure rate.

Assessment of Filtration Bleb and Endplate Positioning Using Magnetic Resonance Imaging in Eyes Implanted with Long-Tube Glaucoma Drainage Devices

Background

To evaluate ocular fluid filtration and endplate positioning in glaucomatous eyes with long-tube glaucoma drainage devices (GDDs) using magnetic resonance imaging (MRI) and the effects of various factors on postoperative intraocular pressure (IOP).

Methods

This observational case series included 27 consecutive glaucomatous eyes (18 men, 7 women; mean age ± standard error, 63.0±2.0 years) who underwent GDD implantation (n = 8 Ahmed Glaucoma Valves [AGV] and n = 19 Baerveldt Glaucoma Implants [BGI]). Tubes were inserted into the pars plana in 23 eyes and anterior chamber in 4 eyes. Six months postoperatively, high-resolution orbital images were obtained using 3-Tesla MRI with head-array coils, and the filtering bleb volume, bleb height, and distances between the anterior endplate edge and corneal center or limbus or between the endplate and orbital wall were measured.

Results

In MR images obtained by three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequences, the shunt endplate was identified as low-intensity signal, and the filtering bleb was identified as high-intensity signals above and below the endplate in all eyes. The 6-month-postoperative IOP level was correlated negatively with bleb volume (r = -0.4510, P = 0.0182) and bleb height (r = -0.3954, P = 0.0412). The postoperative IOP was significantly (P = 0.0026) lower in BGI-implanted eyes (12.2±0.7 mmHg) than AGV-implanted eyes (16.7±1.2 mmHg); bleb volume was significantly (P = 0.0093) larger in BGI-implanted eyes (478.8±84.2 mm³) than AGV-implanted eyes (161.1±52.3 mm³). Other parameters did not differ.

Conclusions

The presence of intraorbital/periocular accumulation of ocular fluid affects postoperative IOP levels in eyes implanted with long-tube GDDs. Larger filtering blebs after BGI than AGI implantations explain lower postoperative IOP levels achieved with BGI than AGV. The findings will contribute to better understanding of IOP reducing mechanism of long-tube GDDs.