Can a history of previous vitrectomy increase the risk for glaucoma post-operatively?

Risk of Glaucoma After Vitrectomy

Vitrectomy surgery increases the risk of developing open-angle glaucoma postoperatively, particularly in patients with risk factors such as family history of glaucoma or those who undergo subsequent cataract surgery.

Mechanism and Evidence

Vitrectomy has been identified as a risk factor for elevated intraocular pressure (IOP) and subsequent development of glaucoma. According to guidelines from the American Academy of Ophthalmology, there is a risk of increase or decrease in postoperative IOP, especially in patients with pre-existing glaucoma 1.

Research evidence demonstrates this association:

• A retrospective study found that 19.2% of vitrectomized eyes developed elevated IOP compared to only 4.5% of unoperated fellow eyes, representing nearly 5 times higher risk 2
• The Edward Jackson lecture reported an increased risk of open-angle glaucoma after vitrectomy, with the lens potentially offering some protection 3
• In patients with pre-existing glaucoma, the vitrectomized eye required significantly more anti-glaucoma medications than the fellow eye (2.9 vs 2.0 medications) 3

Risk Factors for Post-Vitrectomy Glaucoma

Several factors increase the likelihood of developing glaucoma after vitrectomy:

1. Family history of open-angle glaucoma (odds ratio 7.2) 2
2. Pseudophakic status (odds ratio 2.5) 2
3. Type of tamponade used during surgery:
   • Silicone oil carries the highest risk (28.4%)
   • Perfluoropropane (C3F8) has a moderate risk (19.8%)
   • Sulfur hexafluoride (SF6) has a lower risk (5.9%) 4
4. Pre-existing elevated IOP 1

Timing of Glaucoma Development

The development of glaucoma after vitrectomy follows a timeline:

• Approximately 68% of cases of elevated IOP occur within the first month after vitrectomy 4
• In phakic eyes, the mean time between vitrectomy and glaucoma development is longer (45.95 months) compared to eyes that were already pseudophakic at the time of vitrectomy (18.39 months) 3
• The protective effect of the lens appears significant, as the presence of a natural lens delays the onset of glaucoma 3

Clinical Implications and Management

Surgeons should discuss the risk of postoperative IOP elevation with patients before vitrectomy, particularly for those with risk factors. The American Academy of Ophthalmology guidelines emphasize that:

• Patients should be informed about the possibility of increased postoperative IOP 1
• Regular follow-up examinations are essential to monitor IOP changes 1
• Patients should be advised about the importance of maintaining scheduled postoperative visits 1

Follow-up Recommendations

For patients who have undergone vitrectomy:

• Examination on postoperative day 1
• Follow-up 1-2 weeks after surgery
• Regular IOP monitoring, especially in the first month when most IOP elevations occur
• Long-term follow-up is necessary as some patients (42%) may require continued IOP-lowering medications at one year 4

Conclusion

The evidence clearly demonstrates that vitrectomy increases the risk of developing open-angle glaucoma. Patients with risk factors such as family history of glaucoma or those requiring tamponade with silicone oil should be monitored particularly closely. Long-term ophthalmologic follow-up is essential for all vitrectomy patients to detect and manage IOP elevations before they result in glaucomatous damage.