[Diagnostic capabilities of ultrasound biomicroscopy in phaco surgery]

Capabilities of ultrasound biomicroscopy (UBM) as a diagnostic method for surgical planning and outcome analysis in nonstandard situations in phaco surgery have been investigated. The study enrolled 270 patients (278 eyes) with pseudophakia and 26 patients (33 eyes) with aphakia. The scanning was done on OTI HF 35-50 Ultrasound System biomicroscope (UBM) - OTI, Canada. An original method of intraocular lens (IOL) position evaluation by means of UBM, providing precise information on relative position of the IOL and ocular axes, planes, and anatomical structures, has been developed. The proposed technique has been applied to determine both whether the position of the IOL is correct (46 eyes) and, if not, which of three types of its dislocation is present (232 eyes). Clinical and functional features of each of the dislocation types have been analyzed. Detailed analysis of UBM scans of 47 patients (47 eyes) showed that secondary glaucoma development was triggered by loss of proper endocapsular fixation of the IOL with consequent traumatic contact between IOL haptics and uveal tract. This contact, on the one hand, leads to excessive wash-out of pigment and obstruction of outflow routes. On the other hand, it causes subacute reactive uveitis which aggravates preexisting ocular hypertension and glaucoma course. It has been demonstrated that UBM performed prior to IOL implantation enables adequate assessment of the implant bed, accounting for lens capsule integrity, ciliary sulcus configuration and parameters, as well as the extent of structural changes in the globe, which may result from trauma, uveitis or improper evacuation of lens matter during cataract removal. Authors recommend to include UBM into assessment of aphakic patients planned for secondary IOL implantation and to decide on IOL model and its fixation type depending on the UBM results.