Cyclodestruction

Cyclodestruction may be done by using diathermy, penetrating cyclodiathermy, cryotherapy, ultrasound, laser or by surgical excision.{{cite web |title=Cyclodestructive Procedures in Treatment of Glaucoma - EyeWiki |url=https://eyewiki.aao.org/Cyclodestructive_Procedures_in_Treatment_of_Glaucoma |website=eyewiki.aao.org}}

Cyclophotocoagulation (CPC), the most common cyclodestructive procedure is done using laser beam of different wavelengths. Ruby laser (693 nm wavelength), Nd:YAG laser (1064 nm wavelength) or diode laser (810 nm wavelength) can be used to perform CPC. Commomon cyclophotocoagulation techniques include transscleral cyclophotocoagulation (TS-CPC), continuous-wave diode cyclophotocoagulation (CW-TSCPC), MicroPulse diode cyclophotocoagulation (MP-TSCPC), endocyclophotocoagulation (ECP) and high-intensity focused ultrasound cyclodestruction (HIFU). Complications are lesser with Trans-scleral diode laser cyclophotocoagulation and Endoscopic diode laser cyclophotocoagulation.{{cite journal |last1=Bloom |first1=P. A. |last2=Tsai |first2=J. C. |last3=Sharma |first3=K. |last4=Miller |first4=M. H. |last5=Rice |first5=N. S. |last6=Hitchings |first6=R. A. |last7=Khaw |first7=P. T. |title="Cyclodiode". Trans-scleral diode laser cyclophotocoagulation in the treatment of advanced refractory glaucoma |journal=Ophthalmology |date=September 1997 |volume=104 |issue=9 |pages=1508–1519; discussion 1519–1520 |doi=10.1016/s0161-6420(97)30109-2 |pmid=9307649 |url=https://pubmed.ncbi.nlm.nih.gov/9307649/ |issn=0161-6420}}{{cite web |title=Glaucoma: Cyclodestruction |url=https://www.aao.org/disease-review/glaucoma-cyclodestruction#:~:text=Cyclodestruction%20procedures%20aim%20to%20decrease,Trans%2Dscleral%20laser%20cycloablation |website=American Academy of Ophthalmology |language=en |date=8 November 2015}}{{cite journal |last1=Ataullah |first1=S |last2=Biswas |first2=S |last3=Artes |first3=P H |last4=O'Donoghue |first4=E |last5=Ridgway |first5=A E A |last6=Spencer |first6=A F |title=Long term results of diode laser cycloablation in complex glaucoma using the Zeiss Visulas II system |journal=The British Journal of Ophthalmology |date=January 2002 |volume=86 |issue=1 |pages=39–42 |doi=10.1136/bjo.86.1.39 |pmid=11801501 |pmc=1770983 |issn=0007-1161}}

Diode laser with a wavelength of 810 nm is used to perform trans-scleral cyclophotocoagulation. In TS-CPC, the laser absorbed by melanin of ciliary processes causes photocoagulation.{{cite journal |last1=Tan |first1=Nicholas Y. Q. |last2=Ang |first2=Marcus |last3=Chan |first3=Anita S. Y. |last4=Barathi |first4=Veluchamy A. |last5=Tham |first5=Clement C. |last6=Barton |first6=Keith |last7=Sng |first7=Chelvin C. A. |title=Transscleral cyclophotocoagulation and its histological effects on the conjunctiva |journal=Scientific Reports |date=10 December 2019 |volume=9 |issue=1 |pages=18703 |doi=10.1038/s41598-019-55102-0 |pmid=31822709 |bibcode=2019NatSR...918703T |s2cid=209169390 |language=en |issn=2045-2322|doi-access=free |pmc=6904490 }} Since it is a painful procedure, TS-CPC is usually performed under retrobulbar or peribulbar anesthesia. Micropulse transscleral diode cyclophotocoagulation (MP-TSCPC), a modified TS-CPC procedure is a more safer procedure.{{cite web |title=Micropulse Transscleral Cyclophotocoagulation - EyeWiki |url=https://eyewiki.aao.org/Micropulse_Transscleral_Cyclophotocoagulation |website=eyewiki.aao.org |language=en}}

{{More|Minimally invasive glaucoma surgery#Endocyclophotocoagulation}}

Endocyclophotocoagulation (ECP) or endoscopic cyclophotocoagulation using an endoscope allows direct view of the ciliary processes during surgery.{{cite journal |last1=Falkenberry |first1=Suzanne M. |last2=Siegfried |first2=Carla J. |title=Endocyclophotocoagulation |journal=Middle East African Journal of Ophthalmology |date=2009 |volume=16 |issue=3 |pages=130–133 |doi=10.4103/0974-9233.56225 |pmid=20142978 |pmc=2813596 |issn=0974-9233 |doi-access=free }} Compared to TS-CPC, tissue disruption is lesser with ECP.

Cyclocryotherapy is done by freezing the ciliary processes of the eye. In neovascular glaucoma, cyclocryotherapy is advised when medical control of IOP is not possible.{{cite book |last1=Bowling |first1=Brad |title=Kanski's clinical ophthalmology : a systematic approach |date=2016 |publisher=Elsevier |location=Edinburgh |isbn=978-0-7020-5572-0 |page=374 |edition=Eighth}}

Inflammation, retinal detachment, hypotony, phthisis bulbi and sympathetic ophthalmia are some common complications of cyclodestructive procedures. Since there is risk of inflammation which lead to hypotony and phthisis bulbi, cyclophotocoagulation must be done with extreme caution in uveitic glaucoma.{{cite book |last1=Ramakrishnan |first1=R. |title=Diagnosis and Management of Glaucoma. |date=2013 |publisher=Jaypee Brothers Pvt. Ltd |location=New Delhi |isbn=978-93-5025-578-0 |page=394}} Pain, hyphema and iridocyclitis are possible complications of TS-CPC. Fibrin exudates, hyphema, cystoid macular edema and loss of vision are possible complications of ECP.

The first surgical procedures to reduce intraocular pressure of the eye, by decreasing production of aqueous humor, by damaging the ciliary body by diathermy, penetrating cyclodiathermy or surgical excision was done in the early twentieth century.{{cite journal |last1=Dastiridou |first1=Anna I. |last2=Katsanos |first2=Andreas |last3=Denis |first3=Philippe |last4=Francis |first4=Brian A. |last5=Mikropoulos |first5=Dimitrios G. |last6=Teus |first6=Miguel A. |last7=Konstas |first7=Anastasios-Georgios |title=Cyclodestructive Procedures in Glaucoma: A Review of Current and Emerging Options |journal=Advances in Therapy |date=2018 |volume=35 |issue=12 |pages=2103–2127 |doi=10.1007/s12325-018-0837-3 |pmid=30448885 |pmc=6267695 |issn=0741-238X}} Cyclodestruction by diathermy was first performed by Weve in 1933.{{cite web |last1=Themes |first1=U. F. O. |title=Cyclodestruction |url=https://entokey.com/cyclodestruction/ |website=Ento Key |date=7 March 2021}} In 1949, Berens et al. described cyclo-electrolysis. Cyclocryotherapy was first described by Bietti in 1950.{{cite journal |last1=Sinha |first1=Ajit |last2=Rahman |first2=A. |title=Cyclocryotherapy in absolute glaucoma |journal=Indian Journal of Ophthalmology |date=1 March 1984 |volume=32 |issue=2 |pages=77–80 |pmid=6526469 |url=https://www.ijo.in/article.asp?issn=0301-4738;year=1984;volume=32;issue=2;spage=77;epage=80;aulast=Sinha |language=en |issn=0301-4738}} Cyclodestruction by cyclophotocoagulation was first performed by Beckman et al., in 1972, using a ruby laser.{{cite journal |last1=Anand |first1=Nandita |last2=Klug |first2=Emma |last3=Nirappel |first3=Abraham |last4=Solá-Del Valle |first4=David |title=A Review of Cyclodestructive Procedures for the Treatment of Glaucoma |journal=Seminars in Ophthalmology |date=17 August 2020 |volume=35 |issue=5–6 |pages=261–275 |doi=10.1080/08820538.2020.1810711 |pmid=32936725 |s2cid=221769458 |issn=0882-0538|doi-access=free }} ECP was developed by Martin Uram in 1992.{{cite web |title=Endoscopic Cyclophotocoagulation (ECP) - EyeWiki |url=https://eyewiki.aao.org/Endoscopic_Cyclophotocoagulation_(ECP) |website=eyewiki.aao.org |language=en}}

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