No single type of laser or set of laser parameters is appropriate for all type of irides. Pure Nd:YAG laser iridotomy is very effective in the light color irides. It was considered as the gold standard for iridotomy. It, however, is less effective and causes some complication such as iris hemorrhage especially in patients with dark iris.

By using the double frequency YAG to make the initial bore and the Nd:YAG laser to complete the perforation, the technique should be able to effectively combine most of the advantages of both lasers whilst avoiding their disadvantages. It is possibly the ideal iridotomy technique to use in the Asian irides. The investigators aim to study the energy use for laser iridotomy comparing between the two techniques as well as objectively measure the variables associated with complications.

Inclusion Criteria:

• Patient in need to have a laser iridotomy

  • primary angle closure glaucoma or
  • primary angle closure or
  • primary angle closure suspect (needed repeated pupil dilation) or
  • fellow eyes of acute angle closure crisis, and

• Age of at least 18 years, and

• Dark iris patients (only black and dark brown color)

Exclusion Criteria:

• Eye with acute angle closure crisis
• Active conjunctiva or corneal infection or inflammation
• Active anterior uveitis
• History of any prior laser treatment
• History intraocular surgery
• Eye with corneal scar
• Corneal haziness obscure iridotomy site
• Endothelial cell count less than 1000 cells/mm2 (pre-laser)
• Iris color other than black or dark brown
• Inability to sit at the slit lamp to have laser done