Cyclocryo

indications,contraindications,types,advantages,procedure of cyclocryo,when to do it cyclocryo, easy to understand

1. CYCLODESTRUCTIVE PROCEDURES DR.ARINO JOHN MS OPHTHALMOLOGY

2. CYCLODESTRUCTIVE PROCEDURES

3. INTRODUCTION Decrease IOP by destroying the ciliary processes and non pigmented ciliary body epithelium which produces the aqueous fluid. Last line management and a reserved procedure.  Because the ciliary epithelium can regenerate, multiple treatments are necessary in some patients to achieve the desired long term IOP lowering effect.

4. indications Refractory ocular pain in absolute glaucoma. Uncontrolled IOP despite max medicat t/t. Multiple failed filtrations or shunt surgery. Cases with severly scarred conjunctiva and poor visual prognosis. NVG

5. Aphakia and pseudophakic glaucoma Glaucoma following PK Traumatic glaucoma Post uveitic glaucoma Congenital glaucoma (failed t/t) indications

6. CONTRAINDICATIONS Thin sclera Limbal deformation Scleritis Phakic eyes with good vision.

7. TYPES of cyclodestructive procedures Cyclocryotherapy Laser cycloablations Cycloelectrolysis Diathermy Beta irradiations Therapeuctic ultrasound.

8. cyclocryotherapy Ideal for a painful blind eye. Destroys the ciliary epithelium with a cryoprobe through intact conjunctiva and sclera. Good pain relief and success rates But high complication rate.

9. EFFECTS OF CRYOTHERAPY Ischemia caused by vascular stasis and the destruction of small caliber blood vessels Ice crystal formation inside cells leading to cell wall rupture Denaturing of lipid- protein complexes Osmotic stress Tissue necrosis Cellular apoptosis after freezing injury by the buildup of toxic concentrations of solutes inside cells

10. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 7 Thus, concentrating the remaining extracellular solutes As Cryotherapy freezes extracellular fluid, pure water crystals form extracellularly The intracellular water is cooling below its freezing point but not forming ice crystals Known as S u percoo l i n g Cell membrane is permeable to supercooled water So the supercooled water will tend to flow out of the cell and freeze externally The net result is- Cellular dehydration Solute concentration intracellularly

11. procedure Under peribulbar / retrobulbar anesthesia A cryoprobe of 2.5mm is used. C ryoconsole Tank of gas (cryogen ) Foot pedal

12. A circular and convex retinal cryoprobe (3mm or 4mm tip) is applied directly on the intact conjunctival surface. The edge of the tip is placed 1-1.5mm from the limbus for 1 minute, thus bringing the center of tip directly over cilliary body Cryotip temp at -80 degree Celsius. 180 degree is treated at one session. The ice-ball is allowed to thaw slowly, rather than using irrigation, to allow maximal effect.

13. For adequate cellular destruction, the thaw phase of cryotherapy is just as crucial. A slow thaw allows for longer vascular stasis and longer exposure to toxic solute levels within the cell The effect is enhanced by repeated freeze-thaw cycles, usually performed 2-3 times known as “ DOUBLE FREEZE THAW TECHNIQUE ” September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 8 THAW PHASE

14. VARIOUS CRYOGENS Freon (boiling point = −29.8 ̊C to −40.8 ̊C) Nitrous oxide (boiling point = −88.5 ̊C) Solid carbon dioxide (melting point = −79 C̊ ) Liquid nitrogen (boiling point = −195.6 C̊ ) Boiling point of liquid nitrogen is by far the lowest , making it the most effective in cell destruction.

15. POSTOPERATIVE CARE COMPLICATIONS

16. Cycloabaltion Procedure by which laser energy is used to destroy te cilry epithelium,stroma and vascular supply. Types Transcleral cyclophotocoagulation contact & non-contact method. Transpupillary endolaser Endoscopic endolase r

17. LASERS USED IN CYCLOABLATION

18. TRANSCLERAL NON-CONTACT METHOD: Under retrobulbar anesthesia . Using slit lamp Site : 1-1.5mm posterior to limbus ( avoid 3 and 9’0clock meridians) Energy – 4 to 8 joules for 20 ms. Special contact lens can be used. Success rate : 50% to 86 %

19. CONTACT METHOD Nd:YAG /Diode laser is used Continuous laser beam . G-probe used 0.5mm to 1mm posterior to limbus . “ POP”sound TRANSCLERAL Nd:YAG Diode 0.7 W 1.5-2 W 0.7S 2.5S

20. ADVANTAGES DISADVANTAGES SIMPLE PROCEDURE VISUAL LOSS EASY FOLLOW UP POSTOP PAIN & INFLAMMATION LOW COST TRANSIENT IOP RISE GOOD SUCCESS RATES PTHISIS BULBII

21. COMPLICATIONS Severe pain Hypotony and phthisis bulbii Visua loss Severe inflammation Acute rise in IOP Scleral thinning Vitreous haemorrhage Hyphaema Vitritis Aqueous misdirection Sympathetic ophthalmitis Corneal decompression Retinal detachment Cataract in phakic patients.