[Partial sphincterectomy in cataract surgery. Clinical and patho-histologic results]

We perform partial sphincterectomy during cataract surgery in cases with very small pupil (< 3 mm). We assume that the small pupil is mainly due to a fibrosis ring of the sphincter muscle.

In 35 patients we performed the complete ophthalmological routine checkup. The pupil diameter was analysed by perimeter: a base value, with light, and in pharmaceutical mydriasis. Moreover 15 preparations were analysed histologically.

Average pupil diameter was: base value 3.76 mm, with light 3.24 mm, in pharmaceutical mydriasis 4.84 mm. The showed pathohistological examination that in all excisions a part of the sphincter muscle was verifiable. We found fibrosis of different grades in various locations.

In most cases functional pupil movement can be verified after operation. In an intended partial sphincterectomy part of the sphincter muscle can be excised. The different pupil diameter is due to the different degree of fibrosis of the sphincter muscle.