Evaluation of the learning curve of laser peripheral iridectomy:the 20^(th)case reaches the turning point

AIM:To explore the learning curve for ophthalmologists at the start of laser peripheral iridectomy(LPI)training.METHODS:The learning curve of 4 doctor groups without previous LPI experience was studied.Three main parameters of LPI were reviewed:total energy,argon energy and neodymium-doped yttrium aluminum garnet(Nd:YAG)energy.Procedures were evaluated in cohorts of 20 cases to identify the turning points of the three variables.RESULTS:There was no significant difference in terms of age or eye among the 4 doctor groups.There were stable trends on the learning curve for the Doctor A and C groups regarding total energy and argon energy.In addition,the turning points on the learning curve were determined after the 20th procedure for the Doctor B and D groups regarding total energy and argon energy.Moreover,the Nd:YAG energy was relatively stable since the first procedure.CONCLUSION:It requires approximately 20 procedures for a beginner to reach a turning point on the learning curve regarding LPI.It can serve as a point of reference or guideline for training beginners to perform LPI.

Intervention of laser periphery iridectomy to posterior iris bowing in high myopic eyes

Background For some high myopic patients with posterior iris bowing, laser periphery iridectomy should be performed pre-operation to prevent pupil block glaucoma if these patients would have phakic intraocular lens implantation to correct high myopia. So we had the opportunity to analysis the influence of laser iridectomy on posterior iris bowing. Methods Eighteen high myopic patients with posterior iris bowing （11 males and 7 females） were involved in the study in Beijing Tongren Eye Center from March 2008 to July 2008. Phakic intraocular lens were implanted to correct their ametropia. The mean age was （32＋6） years （range, 25-40 years）. The center anterior chamber depth, the pupil diameter, the posterior iris bowing depth and the anterior chamber angle were measured with anterior segment coherence tomography （AS-OCT） under the normal condition, myosis condition induced by 2% pilocarpine, laser periphery iridectomy after myosis, and 2% pilocarpine eluting condition respectively. Results There was no significant difference of center anterior chamber depth under the four conditions （P=0.512）. The pupil constricted after pilocarpine （P=0.001）. After＇ laser iridectomy performed and pilocarpine eluted, posterior iris bowing depth reduced more than that in normal condition （P=0.003）. The anterior chamber angle reduced significantly after laser periphery iridectomy and pilocarpine eluted （P=0.012）. Conclusion Laser periphery iridectomy can reduce the posterior iris bowing, which might be due to the change in aqueous circulate pathway.