Cyclophotocoagulation and cyclocryocoagulation as primary surgical procedures for open-angle glaucoma

Gorsler, Isabel; Thieme, Hagen; Meltendorf, Christian

doi:10.1007/s00417-015-3159-z

Cited by 16 publications

(19 citation statements)

References 25 publications

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“…The freeze-thaw cycles removed all meshwork cells, including those in the corneoscleral and cribriform TM which account for at least 50% of trabecular outflow resistance, whereas most of these cells were preserved in the saponin group. It is possible that the IOP reduction seen after cyclocryodestruction is at least partially due to an improvement of conventional outflow and not only due to reduced aqueous humor production or uveoscleral outflow enhancement from inflammation ( Gorsler, Thieme & Meltendorf, 2015 ).…”

Section: Discussionmentioning

confidence: 99%

Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model

Dang

Waxman

Wang

et al. 2017

PeerJ

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ObjectiveThe trabecular meshwork (TM) is the primary substrate of outflow resistance in glaucomatous eyes. Repopulating diseased TM with fresh, functional TM cells might be a viable therapeutic approach. Decellularized TM scaffolds have previously been produced by ablating cells with suicide gene therapy or saponin, which risks incomplete cell removal or dissolution of the extracellular matrix, respectively. We hypothesized that improved trabecular meshwork cell ablation would result from freeze-thaw cycles compared to chemical treatment.Materials and MethodsWe obtained 24 porcine eyes from a local abattoir, dissected and mounted them in an anterior segment perfusion within two hours of sacrifice. Intraocular pressure (IOP) was recorded continuously by a pressure transducer system. After 72 h of IOP stabilization, eight eyes were assigned to freeze-thaw (F) ablation (−80 °C × 2), to 0.02% saponin (S) treatment, or the control group (C), respectively. The TM was transduced with an eGFP expressing feline immunodeficiency viral (FIV) vector and tracked via fluorescent microscopy to confirm ablation. Following treatment, the eyes were perfused with standard tissue culture media for 180 h. TM histology was assessed by hematoxylin and eosin staining. TM viability was evaluated by a calcein AM/propidium iodide (PI) assay. The TM extracellular matrix was stained with Picro Sirius Red. We measured IOP and modeled it with a linear mixed effects model using a B-spline function of time with five degrees of freedom.ResultsF and S experienced a similar IOP reduction of 30% from baseline (P = 0.64). IOP reduction of about 30% occurred in F within 24 h and in S within 48 h. Live visualization of eGFP demonstrated that F conferred a complete ablation of all TM cells and only a partial ablation in S. Histological analysis and Picro Sirius staining confirmed that no TM cells survived in F while the extracellular matrix remained. The viability assay showed very low PI and no calcein staining in F in contrast to many PI-labeled, dead TM cells and calcein-labeled viable TM cells in S.ConclusionWe developed a rapid TM ablation method that uses cyclic freezing that is free of biological or chemical agents and able to produce a decellularized TM scaffold with preserved TM extracellular matrix in an organotypic perfusion culture.

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Section: Discussionmentioning

confidence: 99%

Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model

Dang

Waxman

Wang

et al. 2017

PeerJ

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“…1,2 Transscleral cyclophotocoagulation utilizing continuous-wave diode laser (TSCP) is a non-incisional procedure for ablating the ciliary body epithelium covering the ciliary processes, thereby reducing the aqueous production and resulting in a lowering of the IOP. 3 Although TSCP is currently the most frequently utilized method of cycloablation, there are other types of transscleral cycloablative procedures such as cyclo-cryocoagulation, 4 ultrasonic coagulation, 5 and micropulse diode laser cyclophotocoagulation. 6 In the current practice, TSCP is generally reserved for patients with limited visual prognosis, despite reports of it being safe and effective for patients with good visual potential.…”

Section: Introductionmentioning

confidence: 99%

<p>Effectiveness and Safety of Long Duration versus Short Duration Diode Laser Transscleral Cyclophotocoagulation</p>

Chan¹,

Chow²,

Lai³

2020

OPTH

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Purpose: To compare the efficacy and safety of diode laser transscleral cyclophotocoagulation using either the long duration or short duration protocol. Methods: Retrospective series of 23 consecutive patients with glaucoma who underwent continuous-wave diode laser transscleral cyclophotocoagulation from August 2016 to July 2018 at a tertiary hospital in Hong Kong. Laser pulse duration for the long and short duration protocols was defined as 3.0-4.0 and 1.5-2.0 s, respectively. Results: There were 15 male and 8 female Chinese subjects (23 eyes), age 49-90 (71.3 ± 2.7), with 10 subjects that underwent long duration cyclophotocoagulation (power 1239.2 ± 78.3 mW, spots 13.9 ± 1.4) and 13 subjects that had short duration cyclophotocoagulation (mean power 1817.3 ± 85.7 mW, spots 14.4 ± 1.0). Six months after long and short duration cyclophotocoagulation, intraocular pressure decreased significantly from 29.9 ± 7.8 to 21.1 ± 6.5 (p < 0.01), and from 35.4 ± 2.7 to 24.1 ± 3.4 (p = 0.04), respectively, while glaucoma medications decreased significantly by 1.4 ± 0.5 (p = 0.02) in the long duration group only. Reduction of medications after short duration cyclophotocoagulation was less and did not reach statistical significance (0.9 ± 0.9, p = 0.15). There was no significant difference of visual deterioration and complication rates. Conclusion: Both types of cyclophotocoagulation were equally effective in lowering intraocular pressure by 6 months, but the short duration protocol, using higher laser power, was able to achieve a greater and earlier reduction, at 3 months. However, the long duration protocol, using less laser power, appears better at reducing medication requirement by 6 months.

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“…Furthermore, the degree of freezing is difficult to gauge, and the placement of the cryoprobe and the operator's technique may have an effect in this regard [16], for example, suboptimal intraoperative centering or moving of the device (which is positioned and maintained manually by the operator). Large contact areas of the cryoprobe may also induce the range that is larger than desired and cause excessive destruction by freezing the ciliary body and collateral tissues resulting in additional side effects such as a drop in visual acuity [17].…”

Section: Discussionmentioning

confidence: 99%

A Comparative Study between Ultrasound Cycloplasty and Cyclocryotherapy for the Treatment of Neovascular Glaucoma

Wang

2020

Journal of Ophthalmology

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Purpose. To compare the clinical efficacy, safety, and histological effect between ultrasound cycloplasty (UCP) and cyclocryotherapy in the treatment of neovascular glaucoma. Methods. Two groups of neovascular glaucoma patients who underwent two types of treatment, respectively, namely, 26 patients treated by UCP and 23 by cyclocryotherapy, were treated and observed during the clinical study for six months. The primary outcome was evaluated by the surgical success, which was defined as the intraocular pressure (IOP) reduction of greater than or equal to 20% from the baseline and the IOP value of greater than 5 mmHg at the last follow-up. The secondary outcome referred to pain relief, complications, and the mean of the IOP at each follow-up. In the animal experiment, 18 New Zealand rabbits were divided into two groups and treated by UCP and cyclocryotherapy, respectively. The changes in the tissues and in the expression of matrix metalloproteinase-1 (MMP-1) were observed immediately. Results. The mean IOP baseline for the UCP and cyclocryotherapy groups was 54.6 ± 9.7 mmHg and 53.3 ± 11.7 mmHg, respectively. After six months of follow-up, the IOP value decreased to 30.3 ± 9.4 mmHg for the patients treated by UCP and to 30.4 ± 9.1 mmHg for those treated by cyclocryotherapy. The two groups achieved a satisfying success rate in the treatment of neovascular glaucoma of up to 70% at least. Vision impairment was observed in some patients treated with cyclocryotherapy, and these patients suffered from more complications and less pain relief than the patients who were treated with UCP. The histological study showed that the ciliary body was completely destroyed after cyclocryotherapy and that MMP-1 was found only in the ciliary muscle. After the UCP treatment, MMP-1 could still be found in the ciliary body, and only the double-layer epithelial cells presented with coagulative necrosis. Conclusion. The UCP treatment and cyclocryotherapy both showed good efficacy in significantly reducing the IOP. However, the UCP treatment was safer with less postoperative complications and adverse effects. Thus, the overall treatment effect of the UCP was more efficient than that of cyclocryotherapy.

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Cyclophotocoagulation and cyclocryocoagulation as primary surgical procedures for open-angle glaucoma

Cited by 16 publications

References 25 publications

Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model

Freeze-thaw decellularization of the trabecular meshwork in an ex vivo eye perfusion model

<p>Effectiveness and Safety of Long Duration versus Short Duration Diode Laser Transscleral Cyclophotocoagulation</p>

A Comparative Study between Ultrasound Cycloplasty and Cyclocryotherapy for the Treatment of Neovascular Glaucoma

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