Rm. Caronia et al., INCREASE IN IRIS-LENS CONTACT AFTER LASER IRIDOTOMY FOR PUPILLARY BLOCK ANGLE-CLOSURE, American journal of ophthalmology, 122(1), 1996, pp. 53-57
PURPOSE: To quantitate changes in anterior ocular segment anatomy afte
r laser iridotomy for pupillary block angle closure. METHODS: We prosp
ectively performed ultrasound biomicroscopy and A-scan biometry in 13
eyes of 13 consecutive untreated patients with relative pupillary bloc
k and appositional angle closure, without peripheral anterior synechia
e on indentation gonioscopy. A radial, perpendicular image in the hori
zontal temporal meridian was obtained with ultrasound biomicroscopy be
fore and one week after laser iridotomy in each eye. RESULTS: Mean age
of the 13 patients was 69.3 +/- 1.8 (S.E.) years, mean refractive err
or was +1.37 +/- 0.39 diopters, and mean axial length was 22.54 +/- 0.
20 mm. In 13 eyes, before and after laser iridotomy measurements of an
gle-opening distance (0.11 +/- 0.02 vs. 0.18 +/- 0.02 mm) (P = .0004;
paired t test), angle aperture (8.3 +/- 1.3 vs 18.6 +/- 2.8 degrees) (
P = .0003) and iris-lens contact distance (0.58 +/- 0.06 vs 1.18 +/- 0
.14 mm) (P = .0003) were greater postoperatively, but anterior chamber
depth was unchanged (P = .7). CONCLUSIONS: Flattening of the iris aft
er laser iridotomy for pupillary block causes an increase in iris-lens
contact. The change in angle configuration after iridotomy results mo
re from an alteration in aqueous pressure gradients across the iris ra
ther than from posterior lens movement.