Exclusion Criteria

• Clinically significant ocular disease as deemed by the Investigator(eg, amblyopia, congenital cataract, congenital glaucoma) that might interfere with the study
• Unwilling or unable to discontinue use of contact lenses at screening until study completion
• Unwilling or unable to suspend use of topical medication at screening until study completion
• Ocular trauma or ocular surgery within the 6 months prior to screening
• Use of any topical prescription or over-the-counter (OTC)ophthalmic medications of any kind within 7 days of screening
• Recent or current evidence of ocular infection or inflammation in either eye (such as current evidence of clinically significant blepharitis, conjunctivitis, or keratitis). Subjects must be symptom-free for at least 7 days prior to screening
• Closed or very narrow-angle that in the Investigator's opinion is potentially occludable if the subject's pupil is dilated
• History of any traumatic (surgical or nonsurgical) or non-traumatic condition affecting the pupil or iris
• Known allergy, hypersensitivity, or contraindication to any component of the phentolamine ophthalmic solution or to any component of the mydriatic agents or vehicle formulation

Systemic:

• Known hypersensitivity or contraindication to α- and/or β-adrenoceptor antagonists
• Clinically significant systemic disease (eg, uncontrolled diabetes, cancer, hepatic, renal, endocrine, or cardiovascular disorders) that in the opinion of the Investigator could interfere with the study
• Subjects with learning disabilities that in the opinion of the investigator could interfere with the study
• Initiation of treatment with or any changes to the current dosage, drug, or regimen of any systemic adrenergic or cholinergic drugs within 7 days prior to screening or during the study(Appendix 4)
• Participation in any investigational study within 30 days prior to screening