Glaucoma drainage devices are capable of helping patients with neovascular glaucoma (NVG) achieve meaningful visual outcomes, according to a study published in BMC Ophthalmology. Although patients with proliferative diabetic retinopathy (PDR) fared better than those with retinal vein occlusion (RVO), various different implants were able to significantly reduce intraocular pressure (IOP) and improve visual acuity (VA), the report shows.
Investigators reviewed 120 eyes of patients with NVG who were managed using a drainage device (61.7% had an etiology of PDR, 23.3% had RVO, and the remaining 15% had other etiologies). This study’s primary outcome measure was visual acuity at 1 year. IOP lower than or equal to 21 mm Hg, no reoperation for elevated IOP, and no loss of light perception were considered secondary outcome measures .
The research team considered 20/60 or better “mild impairment,” 20/70 to 20/200 “moderate impairment,” 20/200 to 20/400 “severe impairment,” and 20/400 to count fingers as “very severe impairment.” Anything better than 20/400 was considered meaningful vision.
After 1 year, eyes with NVG that had an etiology of PDR had better acuity compared with eyes with an etiology of RVO (P =.041), the study says. Of patients in the PDR group, 51% still had meaningful vision after 1 year, while 29% from the RVO group had this level of vision (P =.039).
Clinicians implanted all the patients in the study with either the Ahmed (New World Medical) or Baerveldt (Abbott Laboratories) glaucoma drainage devices during cataract surgery. The average final IOPs between patients who received each of the devices were not significantly different (17.0±7.6 for the Ahmed group vs 14.6±7.8 for the Baerveldt group) and was also not significantly different when the RVO and PDR groups were analyzed separately (17.3 Ahmed vs 12.5 Baerveldt in the RVO group, and 17.5 vs 16.7 in the PDR group), according to investigators. There was a statistically significant difference in the mean number of glaucoma medications with Ahmed eyes (n=70) requiring 1.9 medications and Baerveldt eyes (n=46) requiring 1.3 (P =.027) at the end of the 1 year.
Researchers speculate that the study’s retrospective nature, the inclusion of a heterogeneous “other etiologies” group, the higher number of PDR than RVO eyes, and strong clinician experience with GDD placement could all be seen as limitations of the study.
“Based on our results, deciding which [glaucoma drainage device] to select remains the discretion of the surgeon,” investigators report. “If drop compliance may be an issue, selecting a Baerveldt could be advantageous as the number of drops needed at 1 year was significantly lower in our study at 1 year.”
Medert CM, Sun CQ, Vanner E, Parrish RK, Wellik SR. The influence of etiology on surgical outcomes in neovascular glaucoma. BMC Ophthalmol. Published online December 20, 2021. doi:10.1186/s12886-021-02212-x