Safety and Efficacy of Second Ahmed Valve Implant in Refractory Glaucoma

The effects of the first versus second glaucoma drainage implant surgery in patients with primary open-angle glaucoma

BACKGROUND

To investigate the outcome of non-valved glaucoma drainage implant surgery (GDIS) in primary open-angle glaucoma (POAG) patients divided in the first GDI group (patients who underwent the first GDIS) and the second GDI group (patients who underwent the second GDIS because of the failed first GDIS).

METHODS

Intraocular pressure (IOP), visual acuity (VA), visual field defect (VFD), medication score (MS), survival rate of GDIS, complications, and patient background was retrospectively analyzed. Two success criteria were set: Criteria (1) IOP reduction ≥ 20% and 5 < IOP ≤ 21, Criteria (2) IOP reduction ≥ 20% and 5 < IOP ≤ 14.

RESULTS

There were 136 eyes of 109 patients in the first GDI group and 32 eyes of 27 patients in the second GDI group. In the first GDI group and II, mean preoperative IOP was 26.7 ± 6.7 mmHg and 23.7 ± 3.5 mmHg, respectively (P = 0.09). No statistically significant difference in postoperative IOP reduction was found between the two groups (P = 0.39). At 5-years postoperative, the Criteria 1 (Criteria 2) survival rate in the first GDI group and the second GDI group was 60.4% (31.7%) and 61.2% (25.6%), respectively (Criteria 1: hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.30-1.35 [P = 0.24]; Criteria 2: HR: 0.81, 95% CI: 0.46-1.44, P = 0.48). No significant difference in VA, VFD change, MS, or complications was observed. Young patient age was the only significant factor for failure in the first GDI group (odds ratio: 0.95, 95% confidence interval: 0.91-1.00, P = 0.03).

CONCLUSION

The second GDIS may be as effective as the first GDIS for IOP reduction in POAG patients, however, there is a high risk of failure in young-age patients and the surgery may be ineffective in eyes requiring Criteria 2.

Sequential Ahmed valve implantation after primary implant surgery in two dogs

OBJECTIVE

To report the outcomes of sequential Ahmed valve implantation in two dogs with uncontrolled intraocular pressure (IOP) after primary Ahmed valve implantation.

ANIMALS STUDIED

A 6-year-old castrated male American Cocker Spaniel (case 1) and a 12-year-old spayed female mixed-breed dog (case 2) presented with glaucoma management in the left eyes of both dogs.

PROCEDURES

Primary Ahmed valve implantation was performed because of uncontrolled IOP despite antiglaucoma medications used in both dogs. The IOP was maintained within the normal range for 14 and 2 months after surgery in cases 1 and 2, respectively. In both cases, the IOP gradually increased, which was assumed to be caused by bleb fibrosis. In particular, in case 2, one bleb revision surgery was performed during that period, but it was unsuccessful. Therefore, we decided to perform sequential implantation surgery.

RESULTS

In case 1, hyphema occurred the day after sequential surgery and resolved with anti-inflammatory treatment. In case 2, it occurred immediately after the surgery and resolved after surgical blood clot removal. IOP remained below 15 mmHg, and menace response was positive until 40 and 23 months after the sequential surgery in cases 1 and 2, respectively. As a long-term complication, cataracts occurred at 17 months in case 1 and 10 months in case 2.

CONCLUSIONS AND CLINICAL RELEVANCE

Sequential implantation surgery in the same eye could be an effective alternative for long-term IOP management and vision maintenance. A better understanding of complications and appropriate postoperative management is essential for better outcomes.

Reimplantation of a drainage valve device in refractory glaucoma. A clinical case

Background: Implantation of various drainage devices is one of the treatments for refractory glaucoma, resistant to traditional surgical methods. The most commonly used glaucoma drainage device for refractory glaucoma is the Ahmed glaucoma valve. However, the long-term success rate of the surgery may be limited because of the development of complications during the late postoperative period. The complications do not allow the control of the achieved intraocular pressure (IOP) level. In such cases, a repeated implantation of the Ahmed valve may be one of the options for the surgical treatment. Clinical case description: Second Ahmed valves were implanted to two patients with refractory repeatedly operated glaucoma at the Department of surgical glaucoma treatment of the S. Fyodorov Eye Microsurgery Federal State Institution in Moscow. Previously, both patients had the Ahmed valves installed at their places of residence. During the postoperative period, one patient was found to have an encapsulated cyst around the drainage body, and later the revision of the operation area was performed. As a result of the repeated Ahmed valve implantation, the IOP compensation was achieved 9 months after the surgery. Conclusion: A repeated implantation of the Ahmed valve may be an option for the surgical treatment, if the first implant failed to control the IOP, in order to compensate the IOP and preserve the visual functions in patients with refractory repeatedly operated glaucoma.

Ultrasound Biomicroscopy Measurements of the Normal Thickness for the Ciliary Body and the Iris in a Middle East Population

Purpose

Ciliary body (CB) and iris thicknesses may change with certain eye diseases as well as between different populations. Here, we report Ultrasound Biomicroscopy Measurements (UBM) of the normal thickness for the CB and the iris from a homogenous population in the Middle East.

Patients and Methods

Sonomed 35-MHz (SONOMED, INC. New York, USA) images were obtained at 4 radial meridians, and the thickness was measured at 3 locations along the radial length of the iris and at the thickest part of the CB. Parameters included mean thickness, median thickness, range, and standard deviation.

Results

Of 46 adult patients, 83 normal eyes were included in this analysis. The overall mean, median iris thicknesses at the iris root, midway along the radial length of the iris, and at the juxtapupillary margin in mm were 0.42, 0.41 ± 0.08, 0.52, 0.51± 0.08, and 0.72, 0.71± 0.1, respectively. The overall mean, median thicknesses of the CB and CB + ciliary processes in mm were 0.72, 0.71 ± 0.1, and 1.42, 1.37 ± 0.2 respectively. Gender, age, side, and height had no impact on iris and/or CB thickness (p>0.05). However, the iris thickness was significantly thicker in the superior quadrant than inferiorly, and in the nasal quadrant than the temporal quadrant (p=0.04), and the CB thickness and the CB + ciliary processes thickness were significantly thicker in the superior quadrant than inferiorly (P = 0.04 and 0.02 consecutively).

Conclusion

We measured in this study the normal thickness of the CB and the iris in normal eyes from homogenous population in the Middle East using ultrasound biomicroscopy. Our findings are essential for the ophthalmic community worldwide and in the Middle East region and can be used as a normative thickness data for the iris and CB in healthy eyes.

Testing the eligibility of glaucoma patients for potential gene therapy among a clinic population

PURPOSE

Glaucoma patients who deteriorate despite standard treatment may benefit from novel gene therapies. Key inclusion criteria for a glaucoma gene therapy trial were devised. A retrospective chart review in a glaucoma clinic population was conducted. Feasibility of gene therapy inclusion criteria and factors associated with progression and fast progression < -1 decibels/year (dB/y) were evaluated.

METHODS

Three hundred and seventy-four primary open-angle glaucoma patients all of whom had performed at least five Swedish interactive threshold algorithm standard visual fields within a 58-month period. Two definitions were applied to characterize visual field progression rate using Guided Progression Analysis for an individual patient based on A, the eye with the greatest visual field loss, or B, the eye with the most rapid progression rate.

RESULTS

Mean rate of visual field progression was  -0.50 dB/y (Definition A) and  -0.64 dB/y (Definition B). 19.0% (A) and 21.9% (B) of eyes, 71 (A) and 82 (B) eyes, were 'fast progressors' (<  -1 dB/y). 37 (A) and 43 (B) eyes met the putative gene therapy inclusion criteria (≥ 50 years; mean deviation ≤  -4 to ≥  -12 or ≤  -20 dB, progression rate between  -1 and  -4 dB/y). Beta blockers (Odds ratio (OR) with 95% Confidence Intervals (CI): 2.84 (1.39-5.80); p = 0.004) (A), (OR (95%CI): 2.48 (1.30-4.75); p = 0.006) (B) and alpha agonists (OR (95%CI): 2.18 (1.14-4.17); p = 0.02) (A), (OR (95%CI) 2.00 (1.08-3.73); p = 0.028) (B) were significantly associated with fast progression.

CONCLUSION

A substantial proportion (10%) of patients in this clinic population would meet recommended gene therapy inclusion criteria.

Long-term comparison of the outcomes of Ahmed Glaucoma Valve surgery between glaucoma surgeons and cornea trained surgeons

PURPOSE

To compare the long-term outcomes obtained by glaucoma surgeons versus cornea trained surgeons performing Ahmed glaucoma valve (AGV) surgery.

METHODS

Of the total 376 patients (3 month to 83 year) conducted in this retrospective study, 130 patients with refractory glaucoma were evaluated who had been followed up for at least six months during ten years period. The primary outcome measure was the surgical success of AGV surgery that was categorized in two groups: (A5 ≤ IOP ≤ 21 mmHg and at least 20% reduction in IOP without any glaucoma medications (complete success) and reduction by using one or more glaucoma medications (qualified success) (B) similar to previous criteria but the cutoff for higher IOP at 16 mmHg without vision loss and the need for medication or re-surgery.

RESULTS

Mean age of the patients was 32.99 ± 24.20 years in the glaucoma surgeon group and 25.18 ± 24.33 years in the cornea trained surgeons group (P = 0.07). The overall success of both methods at the end of four years were 66.7% and 41.7% for the group of glaucoma surgeons and cornea trained surgeons, respectively (p = 0.661). The cumulative success according to criterion A and B was 66.7% in the glaucoma surgeon group and 47.1% in the others surgeon group (P = 0.661). Repeated glaucoma surgery was required in 33.3% and 52.9% of the patients in the glaucoma surgeon and cornea trained surgeons groups, respectively (P = 0.661). Although there was a significant difference for IOP among various follow-up periods (p = 0.004), this difference was not significant between the two groups (p = 0.374).Visual Acuity did not have a signifiant difference between various follow-up periods and surgeons groups (p = 0.419 and P = 0. 690, respectively).

CONCLUSION

There were comparable outcomes with regard to complications and success rates between glaucoma surgeons and cornea trained surgeons performing AGV surgery.

The Effect of Ocular Perfusion Pressure on Retinal Thickness in Young People with Presumed Systemic Hypotension

Low ocular perfusion pressure (OPP) may increase the risk of optic neuropathy. This study investigated the effects of OPP on the ganglion cell complex (GCC) and optic nerve head-retinal nerve fibre layer (ONH-RNFL) thickness in presumed systemic hypotensives (PSH). Fifteen participants with PSH and 14 controls underwent automated sphygmomanometry and Icare tonometry to calculate OPP: mean OPP (MOPP), systolic OPP (SOPP), and diastolic OPP (DOPP). ONH-RNFL and macula GCC thickness were evaluated using the Optovue iVue optical coherence tomographer. Statistical analysis comprised independent t-tests, the Mann-Whitney U test and binary logistic regression analysis. There was no significant difference when comparing ONH-RNFL and macula GCC thickness between both groups. Increased MOPP (OR = 0.51; 95% CI: 0.27-0.97; p = 0.039) and SOPP (OR = 0.79; 95% CI: 0.64-0.98; p = 0.035) were significantly associated with a decreased risk of reductions in GCC total thickness. Increased SOPP (OR = 0.11; 95% CI: 0.01-0.89; p = 0.027) was significantly associated with a decreased risk of reductions in the average ONH-RNFL thickness. The study found no significant retinal thickness changes in PSH's, in comparison to the controls. The study established that, by increasing MOPP and SOPP, there was a decreased risk of reductions in the total GCC thickness and average ONH-RNFL thickness. Higher SOPP may decrease the possibility of retinal thinning of the GCC and ONH-RNFL. However, higher MOPP may decrease the odds of thinning of the GCC before ONH-RNFL changes.

Stem Cell-Based Regeneration and Restoration for Retinal Ganglion Cell: Recent Advancements and Current Challenges

Glaucoma is a group of irreversible blinding eye diseases characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons. Currently, there is no effective method to fundamentally resolve the issue of RGC degeneration. Recent advances have revealed that visual function recovery could be achieved with stem cell-based therapy by replacing damaged RGCs with cell transplantation, providing nutritional factors for damaged RGCs, and supplying healthy mitochondria and other cellular components to exert neuroprotective effects and mediate transdifferentiation of autologous retinal stem cells to accomplish endogenous regeneration of RGC. This article reviews the recent research progress in the above-mentioned fields, including the breakthroughs in the fields of in vivo transdifferentiation of retinal endogenous stem cells and reversal of the RGC aging phenotype, and discusses the obstacles in the clinical translation of the stem cell therapy.

Influence of Trace Elements on Neurodegenerative Diseases of The Eye-The Glaucoma Model

Glaucoma is a heterogeneous group of chronic neurodegenerative disorders characterized by a relatively selective, progressive damage to the retinal ganglion cells (RGCs) and their axons, which leads to axon loss and visual field alterations. To date, many studies have shown the role of various elements, mainly metals, in maintaining the balance of prooxidative and antioxidative processes, regulation of fluid and ion flow through cell membranes of the ocular tissues. Based on the earlier and current research results, their relationship with the development and progression of glaucoma seems obvious and is increasingly appreciated. In this review, we aimed to summarize the current evidence on the role of trace elements in the pathogenesis and prevention of glaucomatous diseases. Special attention is also paid to the genetic background associated with glaucoma-related abnormalities of physiological processes that regulate or involve the ions of elements considered as trace elements necessary for the functioning of the cells.

Tryptophan Pathway Abnormalities in a Murine Model of Hereditary Glaucoma

Background: It has been shown that a possible pathogenetic mechanism of neurodegeneration in the mouse model of glaucoma (DBA/2J) may be an alteration of kynurenic acid (KYNA) in the retina. This study aimed to verify the hypothesis that alterations of tryptophan (TRP) metabolism in DBA/2J mice is not limited to the retina. Methods: Samples of the retinal tissue and serum were collected from DBA/2J mice (6 and 10 months old) and control C57Bl/6 mice of the same age. The concentration of TRP, KYNA, kynurenine (KYN), and 3-hydroxykynurenine (3OH-K) was measured by HPLC. The activity of indoleamine 2,3-dioxygenase (IDO) was also determined as a KYN/TRP ratio. Results: TRP, KYNA, L-KYN, and 3OH-K concentration were significantly lower in the retinas of DBA/2J mice than in C57Bl/6 mice. 3OH-K concentration was higher in older mice in both strains. Serum TRP, L-KYN, and KYNA concentrations were lower in DBA/2J than in age-matched controls. However, serum IDO activity did not differ significantly between compared groups and strains. Conclusions: Alterations of the TRP pathway seem not to be limited to the retina in the murine model of hereditary glaucoma.