A new rebound tonometer for home monitoring of intraocular pressure.

BACKGROUND: To compare intraocular pressure (IOP) measurements obtained by the Icare ONE rebound tonometer (RTONE) and the Goldmann applanation tonometer (GAT) in healthy persons and glaucoma patients in a prospective study, and to investigate the influence of central corneal thickness (CCT). METHODS: Measurements on 126 right eyes were obtained by three equally skilled ophthalmologists with each of the above-mentioned tonometers. In addition, patients measured their own IOP with the RTONE (RTONE(p)). The means and standard deviation for all tonometers were compared. Agreement between the tonometers was calculated using the Bland-Altman method. RESULTS: A total of 95 (75.3%) patients were able to perform correct self-tonometry. Mean IOPs obtained were 17.1 ± 5.9 mmHg (RTONE performed by ophthalmologist: RTONE (o)), 17.3 ± 5.6 mmHg (RTONE(p)) and 16.5 ± 5.1 mmHg (GAT). Correlation analysis indicated a good correlation between IOP readings obtained using RTONE(o) and RTONE(p) (ρ = 0.916; p < 0.001) and RTONE(o) and GAT (ρ = 0.901; p < 0.001). Bland-Altman analysis revealed a mean difference (bias) between RTONE(o) and RTONE(p), between RTONE(o) and GAT, and between RTONE(p) and GAT of -0.2, 0.6, and 0.8 mmHg, respectively, with 95% limits of agreement of -5.0 to 4.5, -4.4 to 5.6, and -4.6 to 6.1 mmHg, respectively. The difference between RTONE(o) and GAT significantly increased with increasing CCT (ρ = 0.004), with a 10% increase in CCT resulting in a 1.8% increase in the difference. CONCLUSIONS: Measurements obtained with the RTONE, either by an ophthalmologist or by the patient, showed an excellent correlation with those provided by applanation tonometry. RTONE generally tends to overestimate IOP compared to GAT readings and displays a dependence on CCT. This study was registered with the DRKS (German Clinical Trials Register; www.germanctr.de ; DRKS00000478).

Capsule excision and Ologen implantation for revision after glaucoma drainage device surgery.

BACKGROUND: There is little information available about surgical management after failed glaucoma drainage device (GDD) surgery. We present the outcome of capsule excision after failed GDD surgery compared to capsule excision with additional use of a biodegradable implant (Ologen, version 2) as a placeholder. METHODS: In an observational comparative case series of 19 patients undergoing excision of the GDD capsule, ten prospectively observed consecutive patients were treated by excision of the capsule, topical mitomycin C application, and implantation of an 10 x 10 x 2 mm-sized Ologen implant (group A) while 9 retrospectively observed consecutive patients were treated by excision of the capsule and topical mitomycin C application alone (group B). RESULTS: Mean preoperative IOP was 29.4 mmHg for group A and 27.6 mmHg for group B, while mean postoperative IOP at the last follow-up (mean follow-up 11.2 (group A) and 8.6 (group B) months) was 17.3 mmHg for group A and 19.3 mmHg for group B (p > 0.05). Follow-up of the two groups demonstrated a significant difference in success rate (log-rank test, p = 0.04) in favor of group A. No further pressure-reducing surgery was necessary in any of the patients in group A, but it was needed in three of nine patients in group B. CONCLUSIONS: Although our study has the limitations of small sample size and observational study design, it shows that further investigation is warranted into the potential of Ologen in revision surgery after GDD implantation.