1. Effect of Primary Phacoviscocanalostomy / Viscocanalostomy On Intraocular Pressure Of Normal Tension Glaucoma Patients: 3-Year Results Derek Ho¹, Adesuwa Garrick¹, Seemeen Aazem¹, Divya Mathews¹ ¹Stanley Eye Unit, Abergele Hospital, Llanfair Road, Abergele, Conwy LL22 8DP United Kingdom
Purpose
To evaluate the efficacy of Viscocanalostomy/ Phacoviscocanalostomy (VC/PV) surgeries in lowering intraocular pressure (IOP) in normal tension glaucoma patients.
Methods
Retrospective Intranet database review of patients who underwent VC/PVC between November 2009 and December 2012 at Stanley eye unit in Abergele Hospital.
Goldmann applanation tonometry (GAT) was used for all IOP measurements which were taken at the time of listing for VC/ PV surgery and at 1 day, 1 week, 1 month, then 3-monthly up to 1 year, then half-yearly up to 3 years post operatively.
The study did not include control group or randomisation. Statistical analysis was done using SPSS software package. A P value of <0.05 was accepted as the level of significance.
Results
A total of 74 patients and 101 eyes were included in the study.
35 were male and 39 were female, with an age range of (76.2±9.2).
A total of 73 PV and 28 VC surgeries were performed.
Comparing the patients who underwent PVC and VC, there was a reduction of 4.53 mmHg for PVC and 5.16 mmHg for VC cases (p=0.35) at 3 years. The final IOP for PVC and VC cases were 13.39±2.53 mmHg and 13.13±2.19 mmHg, respectively (p=0.63)
11 (11%) of 101 operated eyes had inadvertent intra-operative perforation of TDW. 2 patients needed LGP at 12 months and 4 were prescribed antiglaucoma drops by 36 months.
The IOP of this subgroup was 12.42±2.57 mmHg at 36 months, compared to those with an intact TDW of 13.71±2.15 mmHg (p=0.058).
The number of anti-glaucoma drops used at 36 months was 0.28±0.61 compared to a 2.74±0.90 pre operatively, 0.08±0.36at 12 months and 0.22±0.52 at 24 months. 73 operated eyes (72%) were drop free at 36 months follow-up.
The mean pre-operative IOP was 18.07±2.44 mmHg. The mean IOP at 6 months post-op was 12.77±2.17 mmHg (p<0.0001). By the end of study period at 36 months the mean IOP was 13.53±2.24 mmHg.
Conclusion
Our results show 25% IOP reduction over three years with 11% complication rate. We propose that a logical surgical management for NTG patients would be viscocanalostomy, thereby keeping trabeculectomy as an alternative.