The purpose of this study is to compare the efficacy on pupillary dilation between the single dose versus the three doses of 1% tropicamide with 10% phenylephrine for complete ocular examination.

To the best of the authors' knowledge, there have been no clinical trials using an appropriate regimen for pupillary dilation up until now. Therefore, the authors were interested to find out the most appropriate regimen for complete ocular examination, based on the finding that a pupil diameter of 6 mm or greater is adequate for indirect ophthalmoscopy. The authors hypothesize that a single dose of 1% tropicamide and 10% phenylephrine is adequate to complete the job and are conducting this prospective randomized clinical controlled trial to prove the hypothesis.

Inclusion Criteria:

• aged between 20 and 80 years old
• dark iris
• require binocular indirect ophthalmoscopy for complete ocular examination
• signed written consent forms

Exclusion Criteria:

• history of ocular trauma
• history of intraocular surgery
• history of laser treatment
• previous eye drop instillation that may affect pupillary dilation
• ocular diseases that may affect pupil size such as Horner's syndrome, Adies' pupil, glaucoma and uveitis
• history of diabetes mellitus, severe hypertension and cardiovascular diseases