Binocular disturbance after glaucoma drainage device implantation

Orbital anatomy magnetic resonance imaging in diplopic versus non-diplopic patients after glaucoma drainage device placement

PURPOSE

New-onset persistent diplopia has become a common complication after glaucoma drainage device (GDD) placement. Understanding the orbital anatomy of such patients may provide information regarding risk of diplopia, GDD selection, and post-operative management. The purpose of this study was to examine the orbital anatomic differences in diplopic and non-diplopic patients after GDD implantation using high-resolution MRI.

METHODS

Seven eyes (N = 4 with diplopia and N = 3 without diplopia after GDD placement) of seven patients that had undergone placement of Baerveldt 250 (B250), Baerveldt 350 (B350), or Ahmed FP7 (FP7) GDD were prospectively enrolled at a single institution. All patients underwent a 3.0T orbital MRI with 3D volumetric T1 and T2 weighted sequence. Images were analyzed for orbital volume, axial length, orbital distances, presence of superior rectus-lateral rectus (SR-LR) band, position of GDD, and SR-LR angles.

RESULTS

Patients with diplopia had smaller mean ± SD orbital axial (911.5 ± 111.8 mm³ vs 931.7 ± 79.7 mm³) and coronal volumes (1162.5 ± 145.5 mm³ vs 1180 ± 34.6 mm³) compared to non-diplopic patients. Average orbital rim distances were larger for the diplopic group. The SR-LR displacement angle for diplopic patients was larger (101.6° ± 8.1 vs 94.7° ± 17.6) while the SR-LR quadrantic angle (86.6° ± 4.2 vs 89.1° ± 4.3) was smaller. SR-LR band was present and intact in all patients. GDD malpositioning was not evident in any patient.

CONCLUSION

The decreased orbital axial and coronal volumes as well as increased orbital rim distances in diplopic patients suggests the need for further studies to understand the role of orbital anatomy in occurrence of diplopia. Dynamic MRI imaging may be helpful in identifying differences in extraocular muscle function that reveal an etiology of diplopia in patients with GDD implantation.

Primary Baerveldt versus trabeculectomy study after one-year follow-up

PURPOSE

To compare a Baerveldt implant and trabeculectomy with respect to intraocular pressure (IOP) and failure rate at 1 year of follow-up. Secondary outcomes are pharmacological therapy and complications at 1 year of follow-up.

METHODS

This was a randomized, comparative study. A total of 119 glaucoma patients without previous ocular surgery were included at the Rotterdam Eye Hospital, the Netherlands. One eye of each subject was randomized to either a Baerveldt glaucoma drainage device (BGI) or trabeculectomy (TE). Follow-up visits were conducted at 1 day, 2 weeks, 6 weeks, 3 months, 6 months and 1 year after surgery.

RESULTS

After one year, the final IOP was equivalent for both treatment groups: 14 ± 4 mmHg (mean ± SD) for the Baerveldt group versus 13 ± 4 mmHg for the trabeculectomy group. Statistically, we found no significant difference in failure rate between the two groups. However, the Baerveldt group needed significantly more medication to decrease IOP. Overall, self-limiting complication rate was similar in both groups. Diplopia, a serious complication, was significantly more present in the BGI group.

CONCLUSION

One year after surgery, TE shows better results than the BGI. The final IOP, IOP reduction and failure rate are similar, but the need for additional IOP lowering medication in the BGI group is higher as well as the complication rate. The increased risk of developing diplopia after placement of a BGI must be taken into consideration.