2.5% v 10% phenylephrine in maintaining mydriasis during cataract surgery

Area of Science:

• Ophthalmology
• Pharmacology

Background:

• Maintaining adequate pupil dilation (mydriasis) is crucial for successful cataract surgery.
• Phenylephrine hydrochloride is commonly used to achieve mydriasis, but its efficacy can vary.

Purpose of the Study:

• To compare the effectiveness of a 10% viscous phenylephrine hydrochloride solution versus a 2.5% aqueous solution in maintaining mydriasis during extracapsular cataract surgery.
• To assess the impact of iris pigmentation on phenylephrine efficacy.

Main Methods:

• Extracapsular cataract surgery was performed.
• Pupil area was measured after nucleus expression.
• Phenylephrine hydrochloride solutions (10% viscous and 2.5% aqueous) were administered.
• Blood pressure was monitored.

Main Results:

• The 10% viscous phenylephrine solution resulted in a 57% larger pupil area post-surgery compared to the 2.5% solution.
• Efficacy was significantly higher in darkly pigmented irises (114% larger pupil area) compared to moderately (70%) or lightly pigmented irises (12%).
• No significant differences in mean blood pressure elevation were observed between the two phenylephrine concentrations.

Conclusions:

• A 10% viscous phenylephrine hydrochloride solution is more effective than a 2.5% aqueous solution for maintaining mydriasis during cataract surgery.
• The enhanced efficacy of the 10% solution is particularly notable in patients with darkly pigmented irises.
• This formulation offers a safe and effective option for optimizing surgical conditions in specific patient populations.