Typical Volume for Diclofenac Eye Drops
The standard volume for diclofenac ophthalmic solution is one drop per application, with typical eye drop volumes ranging from 25-70 microliters, though optimal therapeutic volumes are 5-15 microliters. 1, 2
FDA-Approved Dosing Regimen
The FDA-approved diclofenac sodium ophthalmic solution 0.1% is administered as follows:
For Cataract Surgery
- One drop applied to the affected eye 4 times daily 1
- Begin 24 hours after cataract surgery 1
- Continue through the first 2 weeks postoperatively 1
For Corneal Refractive Surgery
- One to two drops within the hour prior to surgery 1
- One to two drops within 15 minutes after surgery 1
- Continue 4 times daily for up to 3 days 1
Physical Characteristics of Eye Drop Volume
Standard commercial eye drop bottles deliver drops between 25-70 microliters in volume, though this varies based on multiple factors 2:
- Dropper tip design and physical characteristics affect drop size 2
- Bottle design and material (glass vs. plastic) influence volume 2
- Physico-chemical properties of the solution alter drop formation 2
- Patient technique during administration impacts delivered volume 2
Optimal Volume Considerations
From a biopharmaceutical and economic perspective, smaller volumes of 5-15 microliters should ideally be instilled 2. The conjunctival sac can only hold approximately 30 microliters, meaning standard drops often result in overflow and waste 2.
Clinical Efficacy Evidence
Diclofenac sodium 0.1% eye drops administered 4 times daily demonstrated equivalent efficacy to 1% prednisolone acetate in controlling postoperative inflammation after cataract surgery 3. No significant differences were observed in objective inflammation markers (anterior chamber cells and flare) from postoperative days 3-28 3.
Important Distinction: Ophthalmic vs. Dermatologic Formulations
Do not confuse ophthalmic diclofenac drops with topical diclofenac gel 4, 5: