[Long-term reduction of intraocular pressure by goniotrepanation or laser trabeculoplasty]

Reports concerning the long term efficacy of goniotrephination or lasertrabeculoplasty are still rather inconsistent. Therefore we once again investigated the long term IOP reduction of these two procedures.

In 1983 we started a prospective monitoring of patients having either goniotrephination or lasertrabeculoplasty. We now reinvestigated the patients originally included in this study (mean follow up 7.7 years, n = 116 patients/143 eyes). IOP reduction was defined to be successful if the following two criteria were met simultaneously: 1. IOP post op < 25 mm Hg. 2. IOP post op < 0.8 x IOP prä op.

According to the criteria given above the long term success rate of goniotrephination was 67%, the long term success rate of lasertrabeculoplasty was 32%. There were no severe complications. The frequency of mild complications during the early postoperative period was the same for eyes with successful long term IOP reduction as for eyes with unsuccessful long term IOP reduction. When eyes with glaucoma chronicum simplex and eyes with secondary glaucomas were evaluated separately the following success rates were found: goniotrephination in eyes with glaucoma chronicum simplex 68%, goniotrephination in eyes with secondary glaucomas 67%, lasertrabeculoplasty in eyes with glaucoma chronicum simplex 37%, lasertrabeculoplasty in eyes with secondary glaucomas 18%. The correlation between successful lasertrabeculoplasty in the first eye and successful lasertrabeculoplasty in the fellow eye was marginally significant (p = 0.1).

The long term IOP reduction is clearly more pronounced after goniotrephination than after lasertrabeculoplasty. However, long term IOP reduction after lasertrabeculoplasty is still better than expected. Mild complications during the early postoperative period obviously do not influence the long term results of both procedures. The success rate of lasertrabeculoplasty in eyes with secondary glaucomas is clearly worse compared to eyes with glaucoma chromicum simplex. There is no difference between these two groups when goniotrephination was performed. The success of lasertrabeculoplasty in the first eye cannot really predict the success of the same procedure in the fellow eye.