DOI: 10.1097/IJG.0b013e3181c29b8a
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Issn Print: 1057-0829
Publication Date: 2010/03/01
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Excerpt
Tham et al1 should be commended for their effort to investigate the effects of phacoemulsification and combined phacotrabeculectomy on drainage angle status in primary angle closure glaucoma in Hong Kong by gonioscopy and ultrasound biomicrosopy (UBM). Gonioscopy and UBM were both good methods used worldwide to evaluate the anterior chamber angle status.2,3 They claim that phacoemulsification alone resulted in greater opening of drainage and greater deepening of anterior chamber than combined phacotrabeculectomy in primary angle closure glaucoma eyes.
However, we noticed that the results of gonioscopy and UBM were not identical in their study. There is no statistically significant difference between phacoemulsification and combined phacotrabeculectomy in the mean extent of synechial angle closure preoperatively (P=0.98) or at 1 year after surgery (P=0.23) by gonioscopy. Such results may indicate that these 2 options of surgery could result in the same extent of drainage angle opening. UBM results in their study indicated that phacoemulsification alone resulted in greater opening of drainage than combined phacotrabeculectomy (P<0.001).
We found that gonioscopy was performed for all the patients (72 eyes) whereas UBM was performed for the patients only in Hong Kong Eye Hospital. The exact number was not mentioned in this article. The different number of patients may influence the conclusion.
From another interesting viewpoint, we noticed among the UBM data, the AOD500 in 3 quarters was from 39 to 450 μm preoperatively. As the authors claimed that “All UBM examinations were performed with great care to avoid inadvertent corneal indentation by the eyecup and artificial opening up of the angle,” there is not even 1 quarter in which AOD500 is zero. Does that mean there was no synechial angle closure or even appositional angle closure of the patients in whom UBM was performed? Such data were not identical with most related articles. The AOD500 range of these articles also included 0, which means angle closure.4,5 This may make the conclusion of this article underpowered and of limited value.
