Definitive Response to Denniss and Artes: The Paired Eyes and Brain in One Person Are One Unit

Nonpenetrating Deep Sclerectomy for Progressive Glaucoma: Long-term (5-year) Follow-up of Intraocular Pressure Control and Visual Field Survival

Purpose

To monitor 5-year outcomes of nonpenetrating deep sclerectomy (NPDS) with mitomycin C (MMC) in a new consecutive patient cohort.

Materials and methods

All eyes undergoing NPDS surgery between 1/08 and 6/12 were monitored for intraocular pressure (IOP), number of antiglaucoma medications (meds), and visual field indices [mean deviation (MD) and corrected pattern standard deviation (CPSD)], relative to the preoperative baseline using the two-tailed paired Student's t test.

Results

Of 106 eyes undergoing NPDS with MMC, mean IOP was 19.7 ± 0.5 [sem] mm Hg preoperatively, 11.9 ± 0.5 at 3 months, 12.5 ± 0.6 at 6 months, 12.4 ± 0.5 at 12 months, 12.6 ± 0.6 at 18 months, 11.1 ± 0.6 at 2 years, 11.8 ± 0.5 at 2.5 years, 11.0 ± 0.5 at 3 years, 11.7 ± 0.5 at 3.5 years, 10.7 ± 0.7 at 4 years, 11.6 ± 0.5 at 4.5 years, and 12.4 ± 0.7 at 5 years (average IOP reduction of 7.8 mm Hg or 37%; p < 10⁻⁶) at 5 years. About 92% of eyes had stable IOP ≥5 and ≤21 mm Hg at 5 years. Mean preoperative meds 2.7 ± 0.1 was reduced to 0.40 ±0.09 at 3 months, 0.51 ± 0.1 at 6 months, 0.38 ± 0.08 at 12 months, 0.49 ± 0.09 at 18 months, 0.41 ± 0.09 at 2 years, 0.39 ± 0.09 at 2.5 years, 0.49 ± 0.1 at 3 years, 0.58 ± 0.1 at 3.5 years, 0.49 ± 0.1 at 4 years, 0.64 ± 0.1 at 4.5 years, and 0.52 ± 0.1 at 5 years, corresponding to mean reduction of 2.2 meds (81%; p < 10⁻²²) at 5 years. Mean deviation and CPSD were stable relative to baseline at all time intervals (R = 0.83–0.94; p < 0.0001).

Conclusion

With appropriate postoperative management, eyes undergoing NPDS can maintain excellent IOP control with minimal medication use and maintain very stable visual fields over an extended time frame.

How to cite this article

Slagle G, Groth SL, Montelongo M, et al. Nonpenetrating Deep Sclerectomy for Progressive Glaucoma: Long-term (5-year) Follow-up of Intraocular Pressure Control and Visual Field Survival. J Curr Glaucoma Pract 2020;14(1):3–9.

Pattern Electroretinography and Visual Evoked Potentials Provide Clinical Evidence of CNS Modulation of High- and Low-Contrast VEP Latency in Glaucoma

Purpose

Both pattern electroretinography (PERG) and visual evoked potentials (VEP) can be performed using low- (15%; Lc) and high- (85%; Hc) contrast gratings that may preferentially stimulate the magno- and parvocellular pathways. We observed that among glaucomatous patients showing only one VEP latency deficit per eye, there appeared to be a very strong tendency for an Hc delay in one eye and an Lc delay in the other.

Methods

Diopsys NOVA-LX system was used to measure VEP Hc and Lc latency among a clinical glaucoma population to find all individuals with either a single Hc or Lc latency abnormality in each eye (group 1), or with greater than 0 and less than 4 Hc or Lc VEP latency abnormalities in the two eyes (group 2) to determine whether a significant inverse correlation existed for these values in either group. Hc and Lc PERG data were also evaluated to assess associated retinal ganglion cell responses.

Results

A strong inverse correlation (P = 0.0000003) was observed between the Hc and Lc VEP latency values among the 64 eyes in group 1. Group 2 provided a comparable result (n = 143; 286 eyes; P = 0.0005). PERG (n = 81; 162 eyes) also showed strong bilateral symmetry for magnitude values (P < 0.0001 for both Lc and Hc in groups 1 and 2).

Conclusions

Bilateral retention of both low-resolution/high-speed and high-resolution/low-speed function may persist with both eyes open despite symmetrically pathologic retinal ganglion cell PERG waveform asynchrony for Hc and Lc stimuli in the paired eyes.

Translational Relevance

Clinical electrophysiology strongly suggests binocular compensation for dynamic dysfunction operates under central nervous system (CNS) control in glaucoma.

Making Basic Science Studies in Glaucoma More Clinically Relevant: The Need for a Consensus

Glaucoma is a chronic, progressive, and debilitating optic neuropathy that causes retinal damage and visual defects. The pathophysiologic mechanisms of glaucoma remain ill-defined, and there is an indisputable need for contributions from basic science researchers in defining pathways for translational research. However, glaucoma researchers today face significant challenges due to the lack of a map of integrated pathways from bench to bedside and the lack of consensus statements to guide in choosing the right research questions, techniques, and model systems. Here, we present the case for the development of such maps and consensus statements, which are critical for faster development of the most efficacious glaucoma therapy. We underscore that interrogating the preclinical path of both successful and unsuccessful clinical programs is essential to defining future research. One aspect of this is evaluation of available preclinical research tools. To begin this process, we highlight the utility of currently available animal models for glaucoma and emphasize that there is a particular need for models of glaucoma with normal intraocular pressure. In addition, we outline a series of discoveries from cell-based, animal, and translational research that begin to reveal a map of glaucoma from cell biology to physiology to disease pathology. Completion of these maps requires input and consensus from the global glaucoma research community. This article sets the stage by outlining various approaches to such a consensus. Together, these efforts will help accelerate basic science research, leading to discoveries with significant clinical impact for people with glaucoma.