Ultrasound Biomicroscopic Evaluation of Postoperative Anterior Segment Changes in Canine Intumescent Cataracts

This study aimed to evaluate pre- and postoperative changes in the iridocorneal angle, ciliary cleft (CC), and ciliary muscle (CM) in canine eyes with intumescent cataracts using ultrasound biomicroscopy (UBM), with comparative reference to normal and non-intumescent cataractous eyes.

UBM was performed preoperatively on 61 eyes from 40 dogs, classified into 3 groups: (a) normal (n = 18), (b) cataract (n = 23), and (c) intumescent (n = 20) groups. Following surgery, UBM measurements were conducted on 51 eyes from 37 dogs: (d) postoperative (PO)-cataract (n = 21) and (e) PO-intumescent (n = 29) groups. Pre- and postoperative measurements were obtained from independent groups of dogs. Parameters analyzed included angle opening distance (AOD), iridocorneal angle (ICA), ciliary cleft width (CCW), ciliary cleft length (CCL), ciliary cleft area (CCA), ciliary body axial length (CBAXL), ciliary process-sclera angle (CPSA), and ciliary body muscle thickness (CBMT).

The intumescent cataract group showed significant narrowing of CC collapse. Postoperatively, ICA and CC were significantly wider in the intumescent group, while no significant postoperative difference was observed in CM thickness.

Intumescent cataracts were characterized by narrowing of the anterior chamber angle and collapse of CC, whereas phacoemulsification was associated with partial widening of CC parameters. These findings suggest that anterior segment structural changes are associated with postoperative prognosis in dogs with intumescent cataracts.