**7. Conclusions**

gulation probes. For this reason, several studies have been conducted to explore the useful‐ ness of posterior segment procedures for the treatment of neovascular glaucoma, most of the

One of the earliest studies was published in 1982 by Sinclair et al, who performed pars plana vitrectomy and lensectomy, and an sclerectomy in 14 eyes with neovascular glaucoma, with poor results. After six months, 64% of eyes had maintained or improved visual acuity, 7% had decreased visual acuity, and 28% lost light perception. This procedure had several com‐ plications, including fibrinous vitritis (71%), suprachoroidal hemorrhage (14%), endophthal‐

Several years later, in 1991, Lloyd et al reported the results of a study in which pars plana vitrectomy and a pars plana Molteno implant were performed in 10 eyes, achieving control of intraocular pressure (21 mmHg or less) in 6 of them. However, three eyes developed vit‐

In 1993, Gandham et al published a study of 20 eyes with glaucoma of difficult management (8 out of which had neovascular glaucoma), that underwent pars plana vitrectomy, and placement of a Molteno or Schocket implant. In six out of the eight eyes (75%), an intraocu‐

In 1995, Luttrull and Avery reported 22 eyes in which pars plana vitrectomy and a pars pla‐ na Molteno implant placement were performed. As an additional procedure, either a liga‐ ture of the implant tube with absorbable suture or perfluropropane gas tamponade were performed, in order to avoid postoperative hypotony. With this procedure, an intraocular pressure of 21 mmHg or less was achieved in all eyes, and stabilization or improvement of visual acuity was achieved in 86% of eyes. Among the postoperative complications, retinal

More recently, Faghihi et al in 2007 published their experience in 18 eyes with neovascular glaucoma that underwent pars plana vitrectomy and pars plana Ahmed valve implant. An intraocular pressure of 21 or less was achieved in 13 eyes (72.2%). Light perception was lost

In these four studies, the justification to introduce the tube through the pars plana into the vitreous cavity instead of the anterior chamber was to avoid complications such as hyphema

The main goal in the struggle with neovascular glaucoma in blind eyes is to control intraoc‐ ular pressure (IOP) and pain. (A Janićijević-Petrović M, 2012). In one prospective study the average value of IOP and eyeball pain intensity was significantly lower after cyclocryocoa‐ gulation. Cyclocryocoagulation could be a good method in the treatment of uncontrolled elevated IOP and pain of progressive NVG resistant to medical and surgical treatment, but does not have any effect on the improvement of sight in these patients. (Kovacić Z, Ivanisev‐

reous hemorrhage, three developed retinal detachment and two lost light perception.

detachement was observed in two eyes, and loss of light perception in one eye.

time performed in conjunction with filtering surgery.

348 Glaucoma - Basic and Clinical Aspects

mitis (7%), retinal detachment (7%) and phthisis bulbi (14%).

lar pressure of 22 mmHg or less was achieved.

in two eyes and two evolved to phthisis bulbi.

*6.4.3. Cycloablation*

ić M, 2004)

or blockage of the tube by a fibrovascular membrane.

The physiopathology of NVG involves various biochemical and biological mechanisms that result in the presence of abnormal vessels that lead to the clinical forms of the disease. This natural history can be modified and steered into a more appropriate and less devastating be‐ havior, depending on the sagacity of the physician and the commitment that the patient has to his/her own condition.

One fundamental aspect of NVG management is the treatment of the underlying condition that caused it. Uncontrolled diabetes, systemic hypertension, vascular diseases, and even primary open angle glaucoma are all modifiable factors that may reduce the incidence of NVG. Periodic ophthalmology visits for patients at risk should be part of their primary care, especially since the prevalence of these systemic conditions seems to be on the rise.

What used to be a condition that was a synonym for irreversible, painful blindness is now expected to be controllable to a degree compatible with useful vision, but through a chal‐ lenging course of treatment.

Three strategies for preserving vision have increasingly improved the visual prognosis in NVG patients. First was the advent of Panretinal Photocoagulation, when done on time pre‐ vented or treated the worst cases of NVG.

The second strategy, and probably the most pivotal turning point, was the arrival of Ahmed valves, permitting control of IOP from day 1, and, in conjunction with PRP, preserving use‐ ful vision for the first time without the frequent failures of trabeculectomies. In our initial series (Gil-Carrasco et al. 1997) 137 NVG eyes had a preoperative IOP of 36.7 (SD 11.2) and it lowered to 13.7 (SD 3.4), around 80% were successful at 12 months. Shunt devices have gained in popularity for the management of NVG.

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The third and newest strategy has been the incorporation of anti-angiogenic agents from the beginning of this century. Our group performed a prospective study on the use of 2.5 mg of intravitreal Bevacizumab plus PRP in 36 patients who had rubeosis iridis (group A), NVG in open-angle phase (Group B) or NVG with at least 180 degrees of angle closure (Group C).

At 1 week all eyes had regression of all visible anterior segment neovascularization. Addi‐ tionally in group B, survival of adequate IOP control using only topical medications, with‐ out progressing to closed-angle phase, was 90% at 3 months, 81% at 6 months, and 70.9% at 9, 12 and 18 months. All eyes in group C had an Ahmed valve implant (AVI) within 96 hours of the intravitreal injection without serious complications, observing only scant intraoperative bleeding in one eye and a 1 mm hyphema in 2 other eyes on the first postoperative day. Kaplan-Meier analysis of group C showed survival of post-AVI IOP control, without further interventions, of 100% at 6 months, 85.7% at 9,12 and 18 months of follow-up. Sur‐ vival rate for neovessel-free anterior segment was 75%, 57.7% and 62.5% at 18 months in groups A, B and C, respectively.

We concluded that Preoperative intravitreal Bevacizumab has an important role as an adjuvant to pan-retinal photocoagulation in neovessels regression, controlling IOP and avoiding angleclosure in open-angle NVG, and for reducing bleeding after Ahmed Valve implantation.

A recent review of 912 Ahmed valve implants without a patch, followed for up to 16 years at our hospital found a 49% success rate for avoiding blindness and maintaining IOP under 21 mmHg. There were 363 NVG cases (39.8%), by far the most frequent indication for Ahmed valve implants and most of them associated with diabetic retinopathy (Gil-Carrasco et al. 2012).

The combination of Ahmed valve implants, anti-angiogenics and full PRP, plus topical antiglaucoma medications as needed, has become the spearhead in the management of neovas‐ cular glaucoma at our institution. New surgical approaches for NVG and a better understanding of the disease offer an encouraging perspective for the visual prognosis of these patients.
