LXII Edward Jackson Lecture: Open Angle Glaucoma After Vitrectomy

Edward Jackson.

Preoperative fundus drawing of the right eye (Patient 1) with large posterior retinal tears and retinal detachment. The intraocular pressures were OD 17 mm Hg, OS 18 mm Hg.

Pre- and postoperative photographs (Patient 1). (Top) A large posterior tear at 12 o’clock was treated with vitrectomy, perfluorocarbon liquid, endolaser, and gas tamponade. No scleral buckle was used. (Bottom) After the operation, the visual acuity was 20/25.

Preoperative fundus drawing (Patient 2) with large posterior horseshoe tear that caused a macular-sparing retinal detachment. Vitrectomy, perfluorocarbon liquid, endolaser, and gas tamponade were done without scleral buckling. The intraocular pressures were normal throughout the perioperative period.

Postoperative fundus montage of attached retina (Patient 2); laser photocoagulation was placed only around the retinal tears. The corrected visual acuity was 20/30.

Patient 2. Four years after vitrectomy, the intraocular pressure was OD 23 mm Hg, OS 17 mm Hg. The patient was followed as a glaucoma suspect for 12 months until asymmetry of the optic cups was noted with enlargement in the right eye. Timolol 0.5% was started in the right eye only.

Graph of intraocular pressure (IOP) over the clinical course of 17 years (Patient 3). IOP was normal and symmetric for many years before vitrectomy for macular pucker. The IOP increased in the vitrectomized left eye just before cataract surgery but did not require treatment until six years later. The IOP in the fellow eye was normal. BID = twice daily.

In general, postvitrectomy open angle glaucoma was controlled successfully with medical therapy. However, a monocular patient who was treated for macular pucker with laser applied to inferior retinal tears required surgery. The cupping increased in the right optic disk, and a tube shunt implant was placed.

In the nonvitrectomized phakic eye, the oxygen tension (pO₂) is lower (arrow) in the center of the vitreous than in the vitreous near the retinal surface.

After vitrectomy, the gradient disappears, and oxygen tension (pO₂) increases (arrow) in the central vitreous, surrounding the lens, eventually causing cataract.

After cataract surgery, the increased level of oxygen in the vitreous no longer is metabolized by the lens and mixes with aqueous humor that passes through the trabecular meshwork (arrows). pO₂ = oxygen tension.

Flow diagram of the role of oxidative stress that is hypothesized to cause an increase in nuclear cataract and open angle glaucoma. The presence of a human lens delays the development of open angle glaucoma.