Assessment Of The Biological Reaction For Subconjunctival Soft Contact Lens As Trabeculectomy Adjuvant In Male Rabbits

To determine safety, efficacy and extent of subconjunctival fibrosis with subconjunctival implanation of a modified part of soft contact lens after trabeculectomy; animal study.

A prospective comparative study on 8 male rabbits (1.5-2 kg weight). The study was adhered to guidelines of animal experimentation of instituational animal care and use committee. The right eye of each subject underwent conventional trabeculectomy(controls). The left eyes underwent trabeculectomy with subconjunctival implantation of a modified part of sterile soft contact lens (oblong shaped about 4×6 mm).

Primary outcome measures at three months: bleb configuration (clinical examination), degree and extent of subconjunctival fibrosis by histological study (hematoxolin and eosin) of all enucleated eyes after scarifying of the rabbits.

At the end of study, 3 months postoperatively, filtering blebs were formed with normal vascularization in all left eyes and in 6 eyes(75%) of control eyes with two eyes with falt avascular blebs. H&E histological study with grading of subconjunctival fibrosis into four grades (0-3). Controls showed (fibrosis grade1 in 1 eyes, grade2 in 2 eyes, grade3 in 2 eyes and grade4 in 3 eyes). The left eyes with subconjunctival CL; fibrosis grade1 found in 4 eyes, grade2 in 3 eyes and grade3 only in one eye).

No cases of blebitis or extrusion were reported.              

Soft contact lens material may be a suitable adjuvant in filtering surgery. It may inhibit subconjunctival fibrosis and improve bleb survival.

Further studies on larger samples are recommended.