Berdahl, John Palmer

Elevated intraocular pressure (IOP) is the most prevalent risk factor for primary open-angle glaucoma. However, IOP alone does not fully describe a mechanical basis for disease in patients with normal tension glaucoma or primary open-angle glaucoma. The translaminar pressure difference (TLPD) theory proposes that the pressure gradient generated by the difference of IOP and cerebrospinal fluid pressure (CSFp) acting at the level of the optic nerve can lead to cupping and glaucoma when IOP is higher than normal and/or CSFp is lower than normal. The study results to date have generally supported the TLPD theory; however, varying methods, populations, and sample sizes make it difficult to compare results. To further assess whether there is an association between low CSFp and open-angle glaucoma, 30 years of clinical data that assess 96,543 lumbar punctures were analyzed. Patients with open-angle glaucoma showed a significantly lower CSFp than randomly selected normal control patients (9.9 ± 3 mm·Hg (n = 86) versus 12.1 ± 3.6 mm·Hg (n = 114), p < 0.001 ) following adjustment for age and sex. This retrospective study provides strong evidence for an association between open-angle glaucoma and low CSFp.

Purpose: The purpose of the study is to describe short-term efficacy and safety of goniotomy with trabecular meshwork excision using the Kahook Dual Blade (KDB, New World Medical Inc., Rancho Cucamonga, CA) in patients with severe or refractory glaucoma. Method: Retrospective multicentric case series of 53 eyes with severe or refractory glaucoma as defined by ICD-10 conducted in the United States, Mexico, and Switzerland. Primary efficacy outcome was a ≥20% decrease in intraocular pressure (IOP) from baseline at 6 months. Secondary efficacy outcome measures were probability of achieving an IOP≤14 or 18 mm Hg at 6 months and the mean IOP change from baseline at 6 months. Medication use required to obtain target IOP at last follow up and adverse effects were analyzed. Results: The proportion of eyes achieving an IOP reduction of >20% from preoperative baseline at 6 months was 57.7% (n=30). The mean IOP decreased from 18.4±6.1 mm Hg at baseline to 13.9±3.5 mm Hg at month 6 (23.9% reduction; P<0.001). At 6 months, 63.5% and 92.3% achieved an IOP≤14 and ≤18 mm Hg, respectively, and the mean number of glaucoma medications was reduced by 1.2±1.3 (36.6%) compared with baseline (P<0.001). The most common adverse event was hyphema (n=29, 34.9%) with spontaneous resolution in all cases. No severe complications were reported. One case presented with uncontrolled IOP and required glaucoma drainage device surgery at 1 month. Conclusions: Goniotomy with trabecular meshwork excision using the KDB could be an alternative surgery for severe or refractory glaucoma, significantly reducing IOP and medication use at 6 months, with a low rate of complications.