Combined surgery for cataract and glaucoma: PDS with absorbable SK-gel implant compared with PDS with non-absorbable T-flux implant – medium-term results

Abstract

Objective:

To compare the efficacy and safety of phacoemulsification – deep sclerectomy (PDS) with absorbable SK-gel or non-absorbable T-flux implantation.

Research design and method:

The study involved eyes after PDS with SK-gel (32 eyes) and T-flux (20 eyes). Primary open angle glaucoma without satisfying intraocular pressure (IOP) control (≥21 mmHg) despite maximally tolerated medication or with progression of the visual field and cataract was the indication for surgery. For statistical analyses, the Mann–Whitney U test, Student’s t-test, pair sequence Wilcoxon test, and analysis of variance were used. Survival analysis was done using the Kaplan–Meier method.

Main outcome measures:

The best corrected visual acuity (BCVA), IOP, anterior and posterior segments of the eye, and number of antiglaucoma medications were examined. Follow-up examinations were performed on days 1 and 7, and at 1, 3, 6, 12, 18 and 24 months. A complete success rate was defined as IOP ≤18 mmHg without and qualified success as IOP ≤18 mmHg with or without antiglaucoma medications.

Results:

After a 24-month follow-up, mean IOP decreased in the SK-gel group from 20.9 ± 6.1 to 13.8 ± 2.1 mmHg (P = 0.000012) and in the T-flux group from 21.1 ± 6.2 to 14.1 ± 1.9 mmHg (P = 0.000006). There was no statistically significant difference between the number of antiglaucoma medications used in either group (P = 0.389). Complete success rates were 69.8% and 61.3%, respectively (P = 0.064) and qualified success rates were 93.2% and 84.1%, respectively (P = 0.034). There were no significant differences in complications between the two groups.

Limitations:

Despite the obtained statistical differences between the investigated groups in the scope of the qualified success rate, the result should not be treated as reliable from a clinical point of view. The influence of the kind of implant on the obtained result and the nature of the decompression space would require confirmation by ultrasound biomicroscopy (UBM), and by analysis of histological specimens but these were not performed. It should also be noted that the groups were not numerous.

Conclusions:

In the case of SK-gel and T-flux application, PDS demonstrates similar efficacy and safety although the qualified success rate in the case of PDS with T-flux is significantly lower after a 24-month follow-up. The study does not indicate the cause of the observed changes but the nature of the intrascleral lake created by the implants used and its role in IOP regulation may be essential.

Key words::

• Absorbable implant
• Deep sclerectomy
• Non-absorbable implant
• Open angle glaucoma
• Phacoemulsification

Transparency

Declaration of funding

No public or private financial support was received for this study.

Declaration of financial/other relationships

M.R., K.L., B.F., J.R., R.P. and A.S. have disclosed that they are employees or consultants of Corneal, IOLTECH Labolatoires, Zeiss and other pharmaceutical companies, which at present are or were the producers of implants used in this study. All study participants (M.R., K.L., B.F., J.R., R.P. and A.S.) have disclosed that they received research support for this study from some pharmaceutical companies. No other disclosures were reported.

The investigations were performed at the Military Health Service Institute In Warsaw where all the authors of this study are employed. The authors have disclosed that they have no proprietary interest in any of the materials, products, or methods mentioned in this article.

Some peer reviewers receive honoraria from CMRO for their review work. The peer reviewers of this paper have disclosed that they have no relevant financial relationships.

Acknowledgment

The translation and the correction of English language were performed by a translator in Poland and then by MedEdit USA (A.D.). Statistical analysis was performed by a professional statistician basing on Statistica 8.0 software (Statsoft Poland). This assistance (translation, correction and statistical analysis) was financed by the first author of the study.

Data in this paper were presented in part as a poster at the 8th European Glaucoma Society Congress, 1–6 June 2008, Berlin.