Toyokawa and associates report the incidence of late-onset ocular hypertension of 4.2% in the absence of crystalline lens and vitreous within average of 48 months. The type of the primary vitreoretinal pathology, sex of the patients, or gauge of vitrectomy instruments had no impact on the development of ocular hypertension. The authors concluded that vitrectomy combined with cataract surgery was the contributing factor.

Another study found phakic eyes were less likely to develop late-onset open-angle glaucoma when compared to pseudophakic eyes within 51 months after vitrectomy (2% vs 13%, P = .025).

Chang suggested the idea of a preserving lens that may protect the anterior segment from oxidative stress and may delay the development of glaucoma in the long term after vitrectomy. Beebe and associates later confirmed the importance of preserving the intraocular environment as much as possible in protecting the eye against the increased oxygen levels at the trabecular meshwork and development of glaucoma. They think that preservation of the vitreous body and the lens, 2 important oxygen consumers, would protect against nuclear sclerotic cataracts and open-angle glaucoma. Alternatively, reducing oxygen levels in the perfusion fluid during vitrectomy, replacing the vitreous gel after vitrectomy, or restoring the structure of the remaining vitreous gel after limited vitrectomy were also proposed.

Although Toyokawa and associates compared their results with nonoperated fellow eyes, and referred to previous similar studies as well as to a study of the prevalence of glaucoma in Japanese individuals, it would also be interesting for the readers to know about the long-term intraocular pressure trends in eyes that underwent nonvitrectomizing vitreous surgery leaving the vitreous and crystalline lens intact: In such a study, Sawa and associates reported no progression of nuclear sclerosis 72 months after the nonvitrectomizing vitreous surgery for epiretinal membrane. Neither is there a clue about the development of late-onset glaucoma, although no specific intraocular pressure results were presented in their article.