Intrascleral fixation of intraocular lens haptics: histological advantages in a comparison with scleral suture fixation in rabbits

Abstract

To disclose histological advantages of intrascleral fixation of intraocular lens haptics, in comparison with scleral suture fixation, in a study with rabbits. Ten white rabbits, 10weeks of age, were used in this experimental histopathological study. After unilateral lensectomy and anterior vitrectomy, an intraocular lens haptic was inserted into one eye of each rabbit. Intrascleral fixation was performed in five rabbits, whereas scleral suture fixation was performed in the others. At postoperative 1week, the globe was enucleated in two rabbits in each group; at postoperative 8weeks, the globe was enucleated in the remaining three rabbits in each group. Sections of the sclera around haptics and sutures were evaluated with haematoxylin and eosin and immunohistochemical staining methods. We assessed severity of inflammation on histopathological photos, taken near the haptic or suture in the sclera, by counting white blood cells. The Mann-Whitney U test was performed to analyse differences in the severity of inflammation between the groups. Samples in the intrascleral fixation group demonstrated reduced irregularity of collagen fibres; reduced infiltration of fibroblasts, giant cells, lymphocytes, neovascular cells, neutrophils and eosinophils and weaker staining for fibronectin (indicating tissue repair) and heat shock protein 70 (indicating cell damage). In addition, reduced white blood cell infiltration was observed in the intrascleral fixation samples at 8weeks in both shallow sclera (p = 0.001) and deep sclera (p = 0.002). Histological analysis showed that intrascleral fixation caused fewer inflammatory changes than scleral suture fixation, with reduced fibroblast migration and production of cytotoxic factors.