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Updated: Feb 11, 2026

Assessing Early Stage Open-Angle Glaucoma in Patients by Isolated-Check Visual Evoked Potential
Published on: May 25, 2020
CO2 laser-assisted sclerectomy surgery compared with trabeculectomy in primary open-angle glaucoma and exfoliative
Judyta Jankowska-Szmul1, Dariusz Dobrowolski1, Edward Wylegala1
1Department of Ophthalmology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, Katowice, Poland.
Purpose:
To report on the efficacy and safety of CO2 laser-assisted sclerectomy surgery (CLASS) compared with trabeculectomy in primary open-angle glaucoma and exfoliative glaucoma.
Methods:
One hundred and thirty-one patients underwent CLASS (66 patients) or trabeculectomy (65 patients) and were followed up for 12 months. 'Complete success' was defined as intraocular pressure (IOP) between 10 and 18 mmHg and reduced by at least 30% from the baseline without medications, while 'qualified success' was compliant with the above criteria with or without the medications.
Results:
Comparing CLASS with trabeculectomy at 1 year, the mean IOP reduction rate was 32.6 ± 10.8% versus 40.6 ± 15.9% (p < 0.001) and the average use of medications was 1.4 ± 1.4 versus 0.7 ± 1.1 (p < 0.05). At 12 months, the complete success rate was 35% for CLASS versus 60% for trabeculectomy (p < 0.01), while the qualified success rate was 74% versus 75%, respectively, with no significant difference in qualified success rate between the groups at any time-point (p > 0.05). Compared with CLASS, patients after trabeculectomy developed a higher rate of early complications (9.1% versus 29.2%, p = 0.004), higher endothelial cell density (ECD) loss (1.4 ± 1.4% versus 6.5 ± 4.8%, p < 0.001), higher astigmatism (0.0 ± 0.1 versus 0.1 ± 0.2, p < 0.001) and significant visual acuity deterioration (0.1 ± 0.1; range 0-2 lines versus 0.4 ± 0.6; range 0-3 lines, p = 0.016).
Conclusion:
Although CLASS shows a less potent hypotensive effect, it is similar to trabeculectomy in the qualified success rate and offers the reduction in medications up to 12 months. With a more attractive complications profile, CLASS may be an alternative to trabeculectomy, especially at the earlier glaucoma stage and in patients with a low ECD.
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