ABSTRACT

Purpose:

The aim of this study is to compare the changes in surgically induced astigmatism with time among two different glaucoma surgery techniques that have been used in cases of progressive glaucomatous optic nerve damage.

Material and Method:

The study group was composed of eyes which have been operated on with classical trabeculectomy (group 1) or deep sclerectomy+trabeculectomy (group 2). Each group consisted of 13 eyes of 12 patients. All eyes were examined preoperatively and postoperatively at 1.week, 1., 3. and 6.month. At these examinations, except intraocular pressure (IOP), corneal power was recorded with keratometer and corneal topographer. The magnitude of absolute astigmatism, and induced astigmatism were determined by vector analysis at each visit and were statistically compared between the study groups.

Results:

The mean (±SD) age of the patients was 56.2±24.0 and 52.5±24.3 in group 1 and 2, respectively. Preoperatively, IOP were 30.77±10.30 and 27.54±11.28 mmHg, and at 6 month of surgery decreased to 12.38±4.13 and 12.08±5.73 mmHg in groups 1 and 2, respectively. At all postoperative visits, a significant decrease in IOP was observed compared to the preoperative measurements (p<0.05). Postoperatively at 1.week of surgery, the mean induced astigmatism values were 1.50±2.16 and 2.60±2.65D in group 1, and 1.66±1.32 and 2.01±1.95D in group 2, with keratometer and corneal topographer, respectively. The difference between the groups was not significant (p>0.05). At following visits, surgically induced astigmatism decreased in both groups with both methods and the difference never reached significant levels with time.

Discussion:

Glaucoma surgeries, particularly in the early period, are likely to be the reason for the changes in the corneal power. It seems that the addition of deep sclerectomy to trabeculectomy does not cause any significant change in surgically induced astigmatism.