Cryotherapy in Ophthalmology

Includes Techniques & Uses of Cryotherapy in Ophthalmology

1. CRYOTHERAPY Moderator- Dr. Rekha B.K. Presenter- Devanshu Arora SEMINAR September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 1

2. INTRODUCTION CRYOTHERAPY (also known as – Cryosurgery, c ryoabalation, cryocautery & cryogenic surgery) I s a technique that uses an extreme cold produced by an instrument to freeze and destroy abnormal tissue. The term "cryotherapy" comes from the Greek Cryo - meaning cold, and therapy - meaning cure. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 2

3. BRIEF HISTORY September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 3

4. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 4 Other Cryogens are- Nitrous Oxide & Freon

5. INTRODUCTION OF CRYOTHERAPY IN OPHTHALMOLOGY September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 5

6. CELLULAR EFFECTS OF CRYOTHERAPY E ffects of cryotherapy include: Ischemia caused by vascular stasis and the destruction of small caliber blood vessels I ce crystal formation inside cells leading to cell wall rupture D enaturing of lipid- protein complexes O smotic stress T issue necrosis C ellular apoptosis after freezing injury by the buildup of toxic concentrations of solutes inside cells September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 6

7. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 7 The net result is- Cellular dehydration Solute concentration intracellularly

8. THAW PHASE 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

9. SALIENT PRINCIPLES OF CRYO-APPLICATION IN CELLULAR & CLINICAL OPHTHALMOLOGY The ability of a cryogen to freeze is dependent on its ability to remove heat, which is determined by its boiling point. The ice ball produced by a cryoprobe becomes warmer as distance from the cryoprobe is increased . A rapid freeze and a slow thaw produce the most cell death . The pathologic hallmark of cryotherapy is ischemic necrosis. Large blood vessels are highly resistant to cryoinjury, while microvasculature is susceptible . September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 9

10. VARIOUS CRYOGENS For Ophthalmological uses the cryogens primarily used for cryotherapy are: F reon (boiling point = −29.8 ̊C to −40.8 ̊C ) Nitrous oxide (boiling point = −88.5 ̊ C) S olid carbon dioxide ( melting point = −79 ̊C ) L iquid nitrogen (boiling point = −195.6 ̊C ) Bo iling point of liquid nitrogen is by far the lowest, making it the most effective in cell destruction . September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 10

11. EQUIPMENTS FOR CRYOTHERAPY Cryoconsole Appropriately sized cryoprobe for the procedure Source of electricity to run the cryoconsole September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 11 The cryoprobe connects to the cryoconsole with insulated tubing that is part of the probe itself

12. Tank of gas (containing the cryogen as liquid form under pressure) It is attached through valves and tubing to the cryoconsole In all retinal cases, an indirect ophthalmoscope and condensing lens September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 12

13. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 13

14. CRYOPROBE A cryoprobe is a closed system where the cryogen is circulated within a metal probe and the cold probe is applied to the tissue . Specifically , the probe is supplied with a cryogen from a pressurized source. For example if the cryogen is liquid nitrogen- It converts to gaseous nitrogen when released & allowed to pass within the probe, cooling the probe to extremely low temperatures . September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 14

15. Probes with varying tip sizes and angulations have been developed for different applications September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 15

16. Cryoprobes for Retina September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 16

17. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 17

18. Patient Preparation For Retinal C ryopexy : Either topical anesthesia or subconjunctival injection of local anesthetic (lignocaine) in the same quadrant as the lesion to be treated. For c onjunctival neoplasms, lid neoplams & trichiasis : Local infiltration of anesthesia is done. For Peripheral Cryoabalation of the retina or choroid and Cyclocryotherapy for glaucoma: Peribulbar Block should be given. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 18

19. TECHNIQUE Before beginning, make sure that there is adequate gas in the tank & that connections have been correctly made and tightened . Proper cooling of the tip should be checked by depressing the foot switch. After appropriate anesthesia has been instituted, the cryoprobe is applied while still warm to the tissue undergoing treatment. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 19

20. The footswitch is then depressed to allow coolant to flow to the tip. An ice ball should form at the tissue at the tip. Once tissue has started adhering to the tip, the probe should not be moved, because of the risk of tearing or breaking the tissue . The freeze application is limited to the time specified depending on the lesion & then it is allowed to thaw. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 20

21. COMPLICATIONS OF CRYOTHERAPY Most complications from ocular cryotherapy are related to surgeon inexperience & Prolonged contact of a cryoprobe or cryospray with surface tissue, leading to an over-freeze . September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 21

22. Depending on the tissue undergoing cryotherapy, the most common complications from cryotherapy include: T ransitory uveitis T emporary chemosis S ubconjunctival hemorrhage C orneal endothelial damage P aralysis of extra ocular muscles from cryotherapy over muscle insertion sites S ector iris atrophy September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 22

23. Although these adverse effects rarely have long-term consequences, Cryosurgery specially with liquid nitrogen should be performed carefully and only after adequate practical experience. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 23

24. Applications of cryotherapy for specific ocular pathologies CRYOTHERAPY FOR SURFACE EYE DISEASES: September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 24

25. SPECIAL CONSIDERATIONS As per various studies it was seen that, If the cryoprobe was placed on the surface of the globe for only 2 - 3 seconds , it was a safe amount of time to apply a cold liquid nitrogen cryoprobe without causing undue damage. A temperature of −25 ̊C at the level of the endothelium will kill these fragile cells, and An ice ball of 5mm or larger will lead to endothelial cell loss . This would happen if freeze time is kept 5 seconds or more September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 25

26. TRICHIASIS Cryotherapy may be used as a treatment option for chronic trichiasis. Cryotherapy is preferred when there are more than one trichiatic lashes together in an area of the eyelid. Freon or Nitrous oxide is used to destroy the follicles by freezing them . September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 26

27. Cryotherapy for trichiasis was first reported in 1997, using a nitrous oxide cryoprobe L ocal treatment of eyelids using a double freeze-thaw technique was used with low temperatures reaching -20 ̊C Success rate is high of more than 90% but complications are common- Eyelid notching & scarring Pigmentary skin changes Destruction of normal eyelashes September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 27

28. BASAL CELL CARCINOMA OF THE EYELIDS It is a malignant tumor derived from cells of the basal layer of the epidermis. Up to 50-60% of BCC affect the lower eyelid Medial Canthus is involved 25-30% of times (C/I for cryo) Upper eyelid – 15% Treatment Modalities include: Surgery Radiotherapy Cryotherapy September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 28

29. Cryotherapy may be used in : Small superficial type of Basal Cell Carcinoma Pigmented variety of Basal Cell Carcinoma Eyelid notching Cryotherapy is contraindicated in : Medial canthal lesions Recurrent Basal Cell Carcinoma Radiotherapy & C ryotherapy are both contraindicated in : Lesions greater than 1cm in diameter Morphea or Sclerosing type of Basal Cell Carcinoma September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 29

30. TECHNIQUE FOR BASAL CELL CARCINOMA Double freeze-thaw cycles are used – With 45 seconds of freeze for tumors ≤ 5mm in size & 60 seconds of freeze for tumors >5mm in size followed by slow thaw. Nitrous oxide probe is used with high flow rate and tip-size 4 x 10 mm of ‘collin’ type. Similar technique was used in a study ( published in- British Journal of Ophthalmology, 2011 “Nitrous oxide cryotherapy for Primary Periocular Basal Cell Carcinoma” – a 5 year follow up) September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 30

31. VERNAL KERATOCONJUNCTIVITIS The giant papillary changes in VKC are collections of neutrophils, eosinophils, lymphocytes, and other leukocytes surrounding a central vascular core Cryotherapy aims at killing the central vascular core of giant papillae September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 31

32. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 32 VARIOUS STUDIES FOR CRYOTHERAPY FOR VKC Sankarkumar et al. studied 30 eyes of 15 patients with VKC , in 1992 who underwent treatment with carbon dioxide cryogen. Reported recurrence was 3.3% at one year Jiang et al. (2006) combined resection, cryotherapy, and amniotic membrane transplantation for the treatment of VKC. It was concluded that resection and cryotherapy combined with AMT is an effective & safe treatment for VKC.

33. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 33 Liquid nitrogen cryotherapy (using a cryoprobe) for VKC in 3 eyes was reported in 2008. (F.W. Fraunfelder, “ Transactions of American ophthalmological Society”, Vol 106, 2008.) G iant papillae recurrence was noted after 1 month. Recurrent VKC was noted with a median time of development as 12 months. C ryotherapy may kill the central vascular core of giant papillae early on (resulting in some positive results after therapy) , But the high rate of recurrence may make cryosurgery an ineffective therapy for Vernal kerato-conjunctivitis .

34. ADJUVANT CRYOTHERAPY WITH PTERYGIUM EXCISSION Various post-excision, adjuvant treatments have been described in the past, with different recurrence rates: 6 % with C onjunctival autograft 13 % with Beta - irradiation 29 % with Mitomycin - C 53 % with excision alone September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 34

35. The use of adjuvant liquid nitrogen cryotherapy of the surgical site was studied in both de novo and recurrent pterygia excision by F.W. Fraunfelder (published – “ Cryotherapy for Pterygia”, ophthalmology V ol 115, No. 12, 2008) In this series, after excision of the pterygia, C ryotherapy with a 2mm cryoprobe was performed , with the tip of the cryoprobe in contact with the corneoscleral limbus for approximately 1 second. A double freeze-thaw technique was used. After cryotherapy, the conjunctiva was closed up to the limbus with 6-0 plain gut sutures. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 35

36. In the de novo pterygia group (median follow up of 24.5 months), only 1 out of 15 patients had a recurrent pterygium Resulting in a recurrence rate of 3.3% per year. In the recurrent pterygia group (median follow up of 27 months), 4 out of 6 patients had a recurrent pterygium after treatment, Resulting in a recurrence rate of 29.6% per year. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 36

37. Thus, liquid nitrogen cryotherapy appears to be an appropriate adjuvant treatment after de-novo pterygia excision to minimize recurrence . However , recurrent pterygia have NOT been shown to be susceptible to adjuvant liquid nitrogen cryotherapy, with high rates of recurrence despite cryotherapy. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 37

38. Conjunctival Intraepithelial Neoplasia and Squamous Cell Carcinoma Conjunctival intraepithelial neoplasia (CIN) is a localized squamous cell neoplasm that is minimally aggressive and confined to the surface epithelium. If the basement membrane is compromised and invaded by the abnormal cells, then the lesion has progressed to Squamous Cell Carcinoma . September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 38

39. Clinically, CIN and squamous cell carcinoma may present as fleshy, elevated lesion at the limbus. Adjacent corneal epithelium may also be involved. Early studies using excision followed by nitrous oxide cryoprobes showed relatively good results with a 9% recurrence rate (with 5 years of follow up). More recently, an optimized technique for excision with ‘ No Touch ’ technique and combined cryotherapy with liquid nitrogen has been described. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 39

40. It includes treatment of the lesion by alcohol epitheliectomy and partial scelroconjunctivectomy using the “no-touch” technique , followed by intra-operative double freeze-thaw cryotherapy applied to the edges of the remaining bulbar conjunctiva & the scleral base if there was episcleral adhesion of the tumor. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 40

41. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 41

42. In a study of 60 patients with CIN and conjunctival squamous cell carcinoma treated with excision and cryotherapy with the same technique , ( by M. Tunc, et al.) A fter a mean follow up of 56 months, the rate of recurrence was 4.5% for CIN and 5.3% for squamous cell carcinoma September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 42

43. Primary Acquired Melanosis and Melanoma of the Conjunctiva Primary acquired melanosis (PAM) of the conjunctiva is a pre-malignant transformation of melanocytic cells in the conjunctiva. It usually manifests in the middle age, as a unilateral, superficial, solitary patch or diffuse pigmentation of the bulbar, forniceal and palpebral conjunctiva. MANAGEMENT – Conjunctival PAM is usually managed by simple observation if it is limited in extent and not rapidly progressive. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 43

44. Prominent or progressive PAM lesions are usually Excised (if small) or Biopsied (if too large to be excised) September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 44

45. Double freeze-thaw cycles of cryotherapy are applied. Excision & Cryotherapy of Primary Acquired Melanoma has proven to be an effective treatment but recurrences can occur. In a recent report of over 100 cases of PAM treated with excision and cryotherapy a fter a 3 year follow-up, the reported rate of PAM recurrence was 27%, with 3% progressing to Melanoma. (J.A. Shields, et al. published- “ Transactions of the American Ophthalmology society”, Vol105, 2007) September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 45

46. CONJUNCTIVAL MELANOMA It can arise: De novo From a preexisting nevus or From Primary Acquired Melanoma (75% cases) Conjunctival melanoma appears as a pigmented , fleshy, mass located in the bulbar, forniceal or palpebral conjunctiva and may exhibit a prominent feeder vessel September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 46

47. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 47

48. Treatment of Conjunctival Melanomas varies according to the extent and location of involvement: Melanomas involving the bulbar conjunctiva & cornea – September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 48

49. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 49 2. CRYOTHERAPY FOR INTRAOCULAR PATHOLOGY: Cryoextraction of Cataract Cyclocryotherapy Cryotherapy for intra-ocular tumors Retinal Breaks & Detachment Retinopathy of Prematurity

50. CRYOEXTRACTION OF CATARACT Cryotherapy was widely used for cataract extraction in the 1970s when Intra-capsular cataract extraction was the treatment of choice for senile cataracts. Since now Intracapsular cataract extraction is not performed, cryotherapy for lens extraction is no more required September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 50

51. TECHNIQUE : A 12-14 mm incision used to be given, the surface of the lens was dried and cryoprobe tip was applied to the lens capsule . The cryogen was then released to pass into the tip causing the tip to cool rapidly and adhere to the lens capsule Once adhesion is complete, the lens can be removed by pulling gently on the cryoprobe September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 51

52. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 52

53. CYCLOCRYOTHERAPY Cyclocryotherapy is a cyclodestructive procedure which aims at destroying the secretory epithelium of the ciliary body. Indications : Refractory glaucoma with poor vision or poor visual potential Pain relief due to elevated IOP in a painful blind eye Neovascular Glaucoma If conventional glaucoma surgery fail to control IOP September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 53

54. Surgical technique of Cyclocryotherapy : Performed usually under peribulbar anesthesia 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 The ice-ball is allowed to thaw slowly, rather than using irrigation, to allow maximal effect. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 54 Cycloabalation can be achieved by Cyclocryotherapy Cyclophotocoagulation with laser

55. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 55

56. Complications include: Reduced visual acuity, uveitis, hemorrhage& phthisis bulbi To reduce the complication rate (particularly phthisis bulbi), the treatment is usually limited to one application at each clock hour (six in total) over 180° All the complications are less common with Trans-scleral Cyclophotocoagulation(TCP) Laser therapy which is a better alternative to cyclocryotherapy. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 56

57. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 57 Post-op regimen : Atropine eye drops and an antibiotic-steroid combination are prescribed. All glaucoma medications are continued post-operatively The full effect of treatment may take 2-4 weeks to become manifest, so a second treatment is not considered until 1 month has passed. If required, the same area may be retreated, or another quadrant may be included.

58. INTRA-OCULAR TUMORS The advantage of cryotherapy to treat intraocular tumors is the ability to treat trans-sclerally. The damage to the sclera is minimal and negligible while the intraocular tumor is destroyed. Indications : Retinoblastoma Retinal Capillary Hemangiomas Vasoproliferative tumors September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 58

59. RETINOBLASTOMA Very small tumors, not more than 3mm in diameter and 2mm thickness can be treated by cryotherapy alone. Vitreous seeds are usually not treatable with cryotherapy unless they are lying in the immediate vicinity of the tumor. Cryotherapy, however in Retinoblastoma is usually used for consolidation of the tumor after chemotherapy. Tumor recurrences when small can also be treated with cryotherapy. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 59

60. PROCEDURE FOR INTRA-OCULAR TUMORS Intra-ocular tumors are treated using a 2.5 mm tip retinal cryoprobe. Lesions located anteriorly are easily treated with cryo since conjunctiva need not be opened. For tumors located posteriorly, limited conjunctival opening is made to make the probe reach posteriorly. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 60

61. With the indirect ophthalmoscope view, indentation caused by the probe tip is positioned under the center of the lesion and freezing is commenced. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 61

62. Freezing is done till the ice ball totally encloses the tumor mass. The probe is allowed to defreeze completely before freezing again. The cycle is repeated thrice Topical steroids are given for a few days. Complications : Retinal edema occurs frequently Less frequently – Secondary Retinal Detachment Retinal Hemorrhages September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 62

63. RETINAL CRYOPEXY It is a procedure employing cryotherapy to induce a chorioretinal scar. It is used for the treatment of retinal tears & detachments. Retinal tears may arise from trauma or traction from the overlying vitreous. Retinal tears may then allow fluid influx between the neurosensory retina and the RPE, causing further extension of the separation and leading to a retinal detachment. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 63

64. PROPHYLACTIC MANAGEMENT OF RETINAL BREAKS 3 Modalities: Cryotherapy Laser photocoagulation Scleral Buckling Retinal tears that should be treated include: Symptomatic tear High Myopes Any break with subretinal fluid more than 1DD H istory of RD in fellow eye Horse-shoe shaped tears September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 64

65. Cryotherapy is preferred over laser photocoagulation in: Hazy ocular media Peripherally located tears near the ora-serrata Small pupils September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 65

66. Cryotherapy may also be used intraoperatively when scleral buckling is done for the treatment of retinal detachment . In a recent RCT, published 2010 (by RP Lira at al .) patients undergoing scleral buckling for rhegmatogenous retinal detachments along with either intra-op cryotherapy or post-op laser retinopexy (1 month later ) The reattachment and post-operative complication rates were similar in both groups September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 66

67. RETINOPATHY OF PREMATURITY ROP is an ischemic retinopathy of premature and low birth weight infants . The development of retinal vasculature begins during week 16 of gestation and can progress to the final weeks of gestation . Premature birth, in conjunction with subsequent iatrogenic oxygen supplementation, halts and alters normal retinal vasculature development, leading to the onset of ROP and abnormal neovascularization. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 67

68. F irst use of cryotherapy to prevent progression of ROP was reported in 1978. This revolutionized the treatment of ROP In this technique, trans-scleral cryotherapy is used to ablate areas of avascular retina and thereby prevent further neovascularization. In 1988, the first multicenter randomized trial of cryotherapy for treatment of ROP (the CRYO-ROP study) was reported. 9751 less than 1251gm babies were studied across 23 centers & one eye was randomized for cryotherapy. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 68

69. Five-year data from the CRYO-ROP study supported the safety and efficacy of cryotherapy treatment of ROP. Ten-year data from the CRYO-ROP study showed long-term value from cryotherapy in preserving visual acuity in eyes with ROP. Cryotherapy has been shown to be an effective treatment for ROP stage 3+ Cryotherapy has been employed to achieve peripheral retinal ablation for ROP since the 1970s but now has largely been replaced by laser photocoagulation. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 69

70. CONCLUSION Cryotherapy in ophthalmology has a rich history and continues to be an important supplement in the treatment of ophthalmic pathology. The use of cryotherapy in ophthalmology has helped advance maturing fields, while in other instances revolutionized patient care (including ocular surface malignancies) . Further applications of cryotherapy in eye disease continue to emerge. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 70

71. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 71

72. REFERENCES Ophthalmology 4 th edition- Yanoff & Duker Clinical Ophthalmology–A Systematic Approach 7 th edition (by Jack J Kanski) American Academy of Ophthalmology(AAO ) BSCS section 12 Indian Journal of Ophthalmology Vol.63, Issue-3 Open Journal of Ophthalmology , 2013, 3, 103- 117 Internet – http ://www.medscape.com http :// www.keelerusa.com February 18, 2015 Department of Ophthalmology, JNMC, Belagavi 72

73. VKC Jiang et al. (2006) combined resection, cryotherapy, and amniotic membrane transplantation for the treatment of VKC. In this study of 16 eyes, fourteen eyes (87.5%) were symptom-free 1 month after surgery with no evidence of VKC on examination. Recurrence of VKC was observed in 2 eyes (12.5%) after cryotherapy. It was concluded that resection and cryotherapy combined with AMT is an effective & safe treatment for VKC. September 09, 2015 Department of Ophthalmology, JNMC, Belagavi 73