IOP reduction after cataract surgery persists up to 10 years in glaucoma patients

Researchers retrospectively evaluated IOP reduction at one year and up to 10 years after cataract surgery in 124 eyes, both with and without glaucoma. IOP reduction was proportional to preoperative IOP, with the highest preoperative IOPs decreasing the most and the lowest increasing slightly. One-year IOP reductions were sustained for 10 years and were similar in patients of all ages. The authors conclude that the aging crystalline lens may be a major cause of ocular hypertension and a precursor to narrow-angle and open-angle glaucoma.

Initially, when the authors averaged the IOP in all eyes to determine IOP reduction, there was no large decrease seen in patients with high preop IOP. When they averaged the IOP in all glaucoma eyes, the mean preop IOP was 17.8 mm Hg and the mean IOP decrease was 2.7 mm Hg, not enough to warrant treating many of the eyes with phacoemulsification and IOL implantation. However, when they stratified the eyes and sorted them into five groups according to preoperative IOP, they found greater IOP reductions than previously reported.

They also propose that cataract surgery may be an effective treatment to prevent many eyes with ocular hypertension from developing glaucoma and may be effective in treating eyes with established adult glaucoma in selected cases.

They write:

"Treating hypertensive eyes by phacoemulsification with IOL implantation appears more effective in preventing or forestalling the development of glaucoma than treatment with glaucoma drops, as reported in the 2002 Ocular Hypertension Treatment Study. The advantages of phacoemulsification with IOL implantation over trabeculectomy in glaucoma include cataract removal, improved visual acuity, quicker visual recovery, less postoperative care, fewer short-term and long-term complications, and adequate IOP reduction if the postoperative target IOP is 18 mmHg. In addition, more ophthalmologists are skilled in the technique. The advantage of trabeculectomy over phacoemulsification with IOL implantation is a greater possible IOP reduction."