The cause of aphakic glaucoma should always be determined because treatment must be directed towards the aetiological mechanism. We have defined early aphakic glaucoma as that occurring within the first 6 postoperative weeks and late aphakic glaucoma as occurring at any later time. Of the various causes of glaucoma in each category, among the most serious and challenging to treat are pupillary block and angle closure. These emanate from postoperative shallow or empty anterior chambers which are associated with wound fistula, choroidal detachment, or a combination of both. Other mechanisms producing aphakic glaucoma are inflammation, alpha chymotrypsin, epithelial downgrowth, and iris cysts. Pressure elevation unrelated to aphakic glaucoma may also result from intraocular tumours, recurrence of glaucoma secondary to uveitis, and undiagnosed preexisting primary glaucoma.