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Contact and noncontact transscleral neodymium:YAG laser cyclophotocoagulation in a rabbit model
T B Choi1, J F Noriega, B J Glasgow
1Department of Ophthalmology, Jules Stein Eye Institute, UCLA School of Medicine 90024, USA.
Purpose:
Contact versus noncontact transscleral neodymium:YAG laser cyclophotocoagulation was compared in a rabbit model with respect to the effects on intraocular pressure and pathologic findings.
Methods:
Thirty-two rabbits received comparable energy levels (2 joules) of contact and noncontact cyclophotocoagulation. Pneumotonometry was performed every other day following treatment.
Results:
For both the 2-week and 8-week periods following treatment, intraocular pressure was significantly lower in eyes receiving contact cyclophotocoagulation than in eyes receiving noncontact cyclophotocoagulation (for the 2-week period, mean difference in intraocular pressure was 5.3 mm Hg, n = 22, p < 0.001; for the 8-week period, mean difference in intraocular pressure was 4.3 mm Hg, n = 17, p < 0.013). Pathologic findings include acute ciliary body hemorrhage and inflammation (1 day), chronic inflammation (1 week), granulation tissue within laser lesions (2 weeks), and marked ciliary body atrophy (8 weeks).
Conclusions:
In our rabbit model, contact cyclophotocoagulation was more effective in lowering intraocular pressure than noncontact cyclophotocoagulation. Both contact and noncontact cyclophotocoagulation produced a variety of pathologic lesions in the rabbit eye, including cataract, phthisis bulbi, and anterior synechiae.