Correlation of postoperative axial length growth and intraocular pressure in congenital glaucoma – a retrospective study in trabeculotomy and goniotomy

Abstract.

Background: This paper investigates the correlation of postoperative intraocular pressure (IOP) with axial length growth in children who underwent either trabeculotomy (TO) or goniotomy (GO) as primary surgery for congenital glaucoma. Methods: Thirty-seven eyes of 21 children with congenital glaucoma who underwent one or two TOs from 1992 to 1997 and 26 eyes of 16 children with congenital glaucoma who underwent one or more GOs from 1974 to 1993 were retrospectively analyzed. None of the eyes had undergone other surgery previously. Thirteen of the TOs were combined with a small trabeculectomy. IOP was measured by handheld applanation tonometry (Perkins). Axial length was measured by ultrasound. The data were analyzed for correlation of postoperative IOP reduction with postoperative axial length growth. Results: Mean duration of follow-up was 27.3 months in the TO eyes and 37.1 months in the GO eyes. Mean pretreatment IOP before surgery was 28.4±6.9 mmHg in the TO eyes and 30.8±8.5 mmHg in the GO eyes. Mean IOP at the end of follow-up was 17.5±5.8 mmHg in the TO eyes and 17.4±10.2 mmHg in the GO eyes. Axial length growth was normalized (proportional or slowed down compared with the nomogram of axial length growth) in 31 of the 37 TO eyes and in 20 of the 26 GO eyes, and was increased in 6 of the TO eyes and 6 of the GO eyes at the end of follow-up. Regarding axial length growth, 6 of 37 TO eyes had increased axial length growth at the end of follow-up. Three of these eyes also did not fulfill the IOP success criterion; 2 of the 3 eyes with normalized IOP had only borderline increased axial length growth. Six of 26 GO eyes had increased axial length growth at the end of follow-up. Five of these eyes did not fulfill the IOP success criterion; 1 eye with normalized IOP had only borderline increased axial length growth. Conclusion: The data show remarkably good correlation of postoperative IOP with postoperative axial length growth. Axial length measurements can therefore help to ascertain halting or progression of congenital glaucoma and thus are considered an important parameter for congenital glaucoma follow-up.