Role of the water-drinking test in medically treated primary open angle glaucoma patients

The Effect of Combined Phacoemulsification and Endo-Cyclophotocoagulation on Intraocular Pressure Fluctuation Assessed by the Water Drinking Test in Patients with Primary Open Angle Glaucoma

INTRODUCTION

The aim of this study was to assess the effect of phacoemulsification and endo-cyclophotocoagulation (phaco-ECP) on intraocular pressure (IOP) fluctuation as assessed by the water drinking test (WDT) in primary open angle glaucoma (POAG).

METHODS

This was a prospective observational study carried out at a tertiary referral centre. POAG patients on topical antiglaucoma medications and planned for phaco-ECP were recruited. WDT was performed before surgery and 6 weeks postoperatively by drinking 10 mL/kg of water in 5 min followed by serial IOP by Goldmann applanation tonometry measurements at 15, 30, 45, and 60 min. Mean IOP, IOP fluctuation (difference between highest and lowest IOP), IOP reduction, and factors affecting IOP fluctuation were analysed.

RESULTS

Twenty eyes from 17 patients were included. Baseline IOP was similar before (14.7 ± 2.7 mm Hg) and after (14.8 ± 3.4 mm Hg, p = 0.90) surgery. There was no difference in mean IOP (17.6 ± 3.4 mm Hg vs. 19.3 ± 4.7 mm Hg pre- and postoperative, respectively, p = 0.26) or peak IOP (19.37 ± 3.74 mm Hg vs. 21.23 ± 5.29 mm Hg, p = 0.25), albeit a significant reduction in IOP-lowering medications (2.2 ± 1.15 vs. 0.35 ± 0.93, p < 0.001) postoperatively. IOP fluctuation was significantly greater (6.4 ± 3.2 mm Hg vs. 4.6 ± 2.1 mm Hg, p = 0.015) with more eyes having significant IOP fluctuation of ≥6 mm Hg (11 eyes [55%] vs. 4 eyes [20%], p < 0.001) postoperatively. Factors that were significantly associated with increased postoperative IOP fluctuations were higher preoperative IOP fluctuation (β = 0.69, 95% CI 0.379-1.582, p = 0.004) and more number of postoperative antiglaucoma medications (β = 0.627, 95% CI 0.614-3.322, p = 0.008).

CONCLUSION

Reducing aqueous production with phaco-ECP does not eliminate IOP fluctuation in POAG patients. The increase in postoperative IOP fluctuation suggests increased outflow resistance after phaco-ECP.

Short-Time Changes of Intraocular Pressure and Biomechanics of the Anterior Segment of the Eye during Water Drinking Test in Patients with XEN GelStent

Purpose: Little is known about short-term changes in intraocular pressure (IOP) following minimally invasive glaucoma surgeries, such as post-XEN GelStent implantation. Although the importance of corneal biomechanics in glaucoma diagnostics has been reported, little work has been conducted on postoperative description of changes when the structure of the anterior segment is altered. The aim of presented study was to evaluate the changes in the biomechanical parameters of the anterior segment of the post-XEN GelStent implantation eyes. Patients and Methods: This investigator-initiated, open-label, prospective, single-center study recruited patients. Patients with primary open-angle glaucoma (POAG) after XEN GelStent implantation versus matched POAG controls (considered as control group/CG) treated pharmacologically were screened. Water loading was conducted using 10 mL of water per kilogram of body weight for ≤5 min. Goldmann applanation tonometry (GAT), corneal hysteresis (CH), and corneal resistance factor (CRF) were performed before water loading and after every 15 min up to 1 h. Results: The water drinking test (WDT) was positive in 3.7% (1 out of 27) of patients in the post-XEN group compared with 22.7% (5 out of 22) of patients in the control group (CG; p < 0.05). Mean fluctuations in GAT during the WDT were higher in the CG group (3.6 ± 2.5 mmHg vs. 2.9 ± 1.3 mmHg, p < 0.001). CRF and CH changed significantly only in the post-XEN group. The mean peak of CH and CRF occurred at 15 and 30 min of the test in the post-XEN group (p = 0.001). Conclusion: WDT is important to assess the ability of compensation mechanisms to reduce fluctuations in IOP after water upload. The relationship between biomechanics of the anterior segment and glaucoma may have substantial impact on surgical outcome evaluation.

Viscotrabeculotomy versus trabeculectomy in the surgical treatment of open angle glaucoma: a single center, randomised controlled trial

PURPOSE

The aim of the study was to compare the effect of viscotrabeculotomy and the effect of trabeculectomy on the intraocular pressure (IOP) in cases of open angle glaucoma (OAG).

STUDY DESIGN

Prospective comparative study.

PATIENTS AND METHODS

The study was conducted on 148 eyes of 148 patients (87 men) presenting with and operated upon for OAG at Mansoura Ophthalmic center of Mansoura University in Mansoura, Egypt from 2012 to 2016. Patients were randomized into viscotrabeculotomy and trabeculectomy groups. Postoperative follow up visits were scheduled at weeks 1 and 2 then months 1, 2, 3, 6, 9, 12, 15, 18, 21 and 24. Complications were noted and managed according to needs. The primary outcome measure was IOP.

RESULTS

The study was conducted on 148 eyes (74 right) of 148 patients (87 men). The mean ± SD (range, median) age of the study patients was 50.1 ± 11.5 (20-67, 53) and 51.1 ± 10.0 (27-65, 54.5) years respectively. The mean ± SD (range, median) IOP of the study eyes on maximal tolerated IOP lowering therapy was 23.15 ± 2.31 (19-30, 23.0) and 23.64 ± 1.87 (20-28, 23.0) mmHg respectively and at the end of the 24 months of follow up was 14.91 ± 2.4 (12-23, 14) and 16.64 ± 2.8 (14-25, 16) mmHg respectively (p =  < 0.0005). Notable complications included a mild hyphema in the viscotrabeculotomy group and an IOP spike in the trabeculectomy group.

CONCLUSIONS

Viscotrabeculotomy and trabeculectomy showed efficacy and safety in OAG patients. The former resulted in better IOP reduction.

Intraocular pressure and corneal biomechanical changes after water-drinking test in glaucoma patients

Purpose:

To evaluate intraocular pressure (IOP) and corneal biomechanical changes after water-drinking test (WDT) in glaucomatous and normal eyes using Ocular Response Analyzer (ORA).

Methods:

This prospective study included 30 medically controlled, 30 surgically treated glaucoma patients and 30 normal individuals. Baseline measurements included central corneal thickness (CCT), ORA-derived corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated IOP (IOPcc), and Goldmann-correlated IOP (IOPg). Measurements were repeated 15, 30, and 60 min after drinking 1000 mL of water. Changes in ORA parameters were compared among the groups.

Results:

All groups showed a significant increase in IOPg and IOPcc at all test points. Peak IOP occurred at 15 min and decreased gradually over time but did not reach the baseline values at 60 min. The surgery group had significantly lower baseline IOPg and IOPcc (10.7 ± 3.1 and 12.8 ± 3.7 mmHg, P = 0.001 and 0.01), lower peak IOPg and IOPcc (14.4 ± 4.6 and 16.2 ± 4.6 mmHg, P = 0.003 and 0.034), and lower percent IOPg and IOPcc fluctuations (13 ± 5.6 and 15 ± 5.9, P = 0.0001 and 0.002), respectively, compared to the medical group. Baseline CH and its fluctuations were not significantly different among the groups. CH decreased to a trough corresponding to peak IOPcc. There was a significant negative correlation between IOPcc and CH (r = −0.609, P < 0.001). The medical group showed more CRF fluctuations compared to normal group.(P = 0.039).

Conclusion:

Surgically treated glaucomatous eyes show less IOP fluctuations and lower peak IOP after WDT compared to medically controlled and normal eyes.

Intraocular pressure response affected by changing of sitting and supine positions

PURPOSE

To assess the intraocular pressure (IOP) time response to change in body position from sitting to supine and from supine to sitting immediately and during rest in each position.

METHODS

Forty-four visually healthy volunteers were recruited for the study. The experiment consisted of the initial sitting position (baseline state), the subsequent lying period and the final sitting period. Both periods were 30 min long. The IOP was measured in the baseline state, immediately after each position change and then in minutes 5, 15, 25 and 30 during each period. The Icare Pro^® rebound tonometer was used.

RESULTS

The mean IOP increased after each position change (2.6 ± 2.4 mmHg after lying down and 2.1 ± 3.1 mmHg after sitting up) and then gradually decreased with time. The mean IOP was 1.41 ± 2.4 mmHg higher in the lying period than in the sitting period; the mean difference was smaller for the lower baseline (0.9 ± 2.2 mmHg) than the higher baseline (1.9 ± 2.5 mmHg). The mean IOP in the final sitting was significantly lower (2.5 ± 1.9 mmHg) than in the initial sitting position. The effect of sex was insignificant.

CONCLUSIONS

There was an immediate increase in IOP as a response to both changes in the body position and the subsequent gradual decrease with time. The IOP difference between lying and sitting position was depended on baseline.