Lens status following glaucoma drainage device does not affect long-term IOP reduction, States study

A new study published in Ophthalmology Glaucoma journal suggests that the lens status of patients following glaucoma drainage device (GDD) implantation may not affect long-term intraocular pressure (IOP) reduction or drug load.

Glaucoma affects over 70 million people and is the main cause of permanent blindness globally. GDDs like the Ahmed and Baerveldt glaucoma implants are increasingly used in the treatment of glaucoma that is resistant to medicinal treatment. Postoperative inflammation is one of the most common consequences of cataract surgery which leads to trabeculectomy failure. Therefore, Jeannette Stallworth and colleagues investigated the impact of GDD implantation on glaucoma outcomes in phakic eyes that later had pseudophakic eye and phacoemulsification.

The study focused on patients who had underwent GDD implantation with at least one follow-up visit within three years postoperatively. Also, GDDs combined with other ophthalmic procedures were excluded. The majority of the implants were Ahmed implants (90%-94%) and adjunctive mitomycin-C was used in 83%-90% of the cases. The participants were categorized into three groups as,

• Group A including Phakic eyes with a natural lens.  
• Group B with Phakic eyes at the time of implantation but underwent cataract surgery within three years.
• Group C included Pseudophakic eyes with an artificial lens.

The intraocular pressure (IOP) and other outcomes were assessed at the interval of 1, 3, 6, 12, 24 and 36 months post-implantation. Multivariable regression models were used to compensate for baseline characteristics. Primary outcome of this study was IOP following GDD implantation. Secondary outcomes were change in number of glaucoma eye drops, visual acuity (VA), and rate of failure, defined as further glaucoma surgery, vision loss to no light perception, or IOP chronically < 5 mmHg or > 21 mmHg or not decreased by 20% from baseline.

The key findings of this study were:

There were 65 eye participants in Group A, 52 in Group B and 126 in Group C which did not contribute to statistically significant differences in mean IOP between the three groups at all time points up to three years postoperatively. This indicates that the lens status or subsequent cataract surgery did not significantly affect IOP control in patients with GDD implants.

Significant improvement in VA was observed in groups A and B when compared to group C at 6 months, one year and two years after implantation. However, by postoperative year 3, the change in VA was comparable across groups. There were no substantial variations in failure rates across groups (P = 0.68).

The study also found that, up to 12 months following cataract surgery, IOP and medicines were identical to the preoperative baseline. Overall, three years following GDD implantation, there were no variations in IOP, glaucoma medicines or failure rates according to lens condition or future cataract surgery. These findings could help to treat people who have both glaucoma and cataracts.

Source:

Stallworth, J. Y., Hekmatjah, N., Yu, Y., Oatts, J. T., Ying, G.-S., & Han, Y. (2024). Effect of Lens Status on the Outcomes of Glaucoma Drainage Device Implantation. In Ophthalmology Glaucoma (Vol. 7, Issue 3, pp. 242–250). Elsevier BV. https://doi.org/10.1016/j.ogla.2024.01.004