Phacoemulsification and intraocular lens implant in eyes with primary angle-closure glaucoma: our experience.

Abstract

Primary angle-closure glaucoma (PACG) is a pathology connected with anatomic alterations of the eye, especially the anterior segment. PACG eyes are characterized by a smaller corneal diameter, a less deep anterior chamber, a greater anteroposterior diameter lens, a more anterior lens position and a reduced axial length. These particular conditions can lead to a pupillary block and iris deposition on the trabecular meshwork with peripheral synechiae formation and uncontrolled increase of intraocular pressure (IOP). A number of studies have shown evidence that PACG with pupillary block is more frequent in the 60–70 year age range and that in its pathogenesis the lens plays an important role. This study aims to verify the variations in the anatomical relationships between the anterior segment structures after phacoemulsification with IOL implant in the capsular sac and their influence on IOP. We considered two groups of patients: one of 12 members (10 women and 2 men), aged between 67 and 78 years, affected with PACG and cataract (group A) and a control of 12 members (7 women and 5 men) aged between 69 and 71 years, with no ocular pathology but cataract (group B). All the patients had phacoemulsification of the cataract surgery with soft acrylic IOL implant in the capsular sac. All were carried out by the same surgeon with access through clear cornea at the point equivalent to 12 h. All the patients were examined by the HUMPHREY model 840 50 MHz ultrabiomicroscope and the I3 HIRES 20 MHz. Measurements were made of anterior chamber depth, chamber angle width and IOP by Goldmann applanation tonometry, before the operation and at 1 month, 3, 6 and 9 months afterwards. Also measured before the operation were the lens thickness and the eyeball axial length (Table 1). Before the operation, group A anterior chamber depth (AC) was 1.87 ± 0.25 mm and at 9 months after the operation it was 3.92 ± 0.31 mm (P < 0.001), the mean increase thus being approximately 2 mm. The group B measures were, before the operation, a mean AC depth of 2.85 ± 0.36 mm and at 9 months after, 4.22 ± 0.21 (P < 0.001), being a mean increase of approximately 1.3 mm. Chamber angle widths were (at the same times) for group A 19.28 ± 5.3° and 36.1 ± 4.8° (P < 0.001), a mean approximate increase of 16.8° while for group B they were 30.25 ± 4.8° and 38.5 ± 4.7° (P > 0.001), a mean approximate increase of 8°. Before the operation, group A's mean IOP was 21.5 ± 2.6 mmHg and at 9 months 15.3 ± 2.1 mmHg without significant variation (P > 0.5). Lens thickness in group A was 5.08 ± 0.31 mm, in group B, 4.52 ± 0.33 (P < 0.001). Axial length in group A was 22.02 ± 0.86 mm and in group B was 23.18 ± 0.82 (P < 0.05) (Table 2). On the results obtained, we can confirm that the presence of a larger lens in an eyeball where the relationships between the CA anatomic structures are different to normal has an importance which is not negligible. Removal of the lens and the implant of a considerably smaller-sized IOL will in part go some way towards harmonizing those relationships and bring the eyeball into a state nearer to that physiologically normal. The fact that the IOP decreases significantly after IOL implant in the capsular sac of eyes affected by PACG confirms the opinions of other authors that, in these eyes, it is important to perform the lens operation before planning glaucoma surgery, always and in any case after a careful study of the anterior segment (Table 3).