Clinical Trial Finds Oral CBD May Control Post-Surgery Eye Pain as Effectively as Opioids

Oral CBD Matches Opioids for Post-Surgery Eye Pain in Clinical Trial

A new clinical trial from researchers affiliated with the University of Florida suggests that oral cannabidiol, better known as CBD, may relieve pain following certain laser eye surgeries as effectively as a commonly prescribed opioid combination.

The findings are especially notable because researchers did not merely compare CBD with a placebo. They directly compared a standardized, low-THC oral CBD formulation with codeine-acetaminophen, a conventional medication used for acute postoperative pain.

According to the study, patients reported no significant difference in pain between the two treatments. Recovery and visual outcomes were also similar, while the CBD regimen produced only minimal side effects.

For patients, physicians and cannabis-policy advocates, this study offers another reason to investigate cannabinoid-based treatments as potential alternatives to opioids. It does not establish that every CBD product can replace prescription pain medication, but it provides a meaningful clinical signal that deserves larger trials.

What Did the CBD Eye-Surgery Study Examine?

The prospective, randomized, crossover clinical trial involved 35 adults undergoing bilateral photorefractive keratectomy, commonly known as PRK. PRK is a laser vision-correction procedure used to treat nearsightedness, farsightedness and astigmatism. Although it can be appropriate for patients who are not ideal candidates for LASIK, the healing process can involve substantial discomfort during the first several days.

Each participant underwent surgery on both eyes at separate times. For one eye procedure, the patient received oral CBD. For the other, the same patient received codeine-acetaminophen. The order of the treatments was randomized.

This self-controlled crossover design is important because every participant experienced both treatment regimens. Rather than comparing two completely different groups of people, researchers could compare each patient’s response to CBD with that same patient’s response to the opioid medication.

The tested CBD regimen was a low-THC oral formulation administered at 50 milligrams twice daily. The comparison treatment was codeine-acetaminophen containing 30 milligrams of codeine and 300 milligrams of acetaminophen, taken as directed for postoperative pain.

CBD and Codeine Produced Comparable Pain Scores

Pain levels peaked on the second day after surgery under both treatment regimens. Researchers found no statistically significant difference in either average pain or maximum pain ratings between CBD and codeine-acetaminophen.

Patients’ uncorrected visual acuity improved significantly by the three-month follow-up, with no treatment-related difference in vision outcomes. Other reported symptoms and quality-of-life measures were also generally equivalent between the two treatments.

The study’s authors concluded that the low-THC oral CBD formulation provided pain control that was non-inferior to codeine-acetaminophen following PRK, with similar recovery outcomes and minimal side effects. They identified oral CBD as a potential opioid-sparing option in refractive surgery and possibly other acute-pain settings, although additional research will be necessary.

What About Side Effects?

The researchers observed a mild change in sensorium—a person’s general level of awareness or sensation—when CBD was used during a participant’s first eye procedure. That effect was not seen when CBD was used for the second procedure, suggesting that unfamiliarity with the treatment or the surgical experience may have played a role.

No major safety signal was reported in the study. Still, “minimal side effects” does not mean that CBD is risk-free. CBD can cause drowsiness, affect how the body processes certain medications and interact with prescription drugs. Product composition also matters enormously.

The trial evaluated a specific, standardized, full-spectrum, low-THC formulation. Its findings should not be generalized to every oil, gummy, capsule or untested CBD item on the market.

Why an Opioid Alternative Matters

Opioids can be effective medications for severe acute pain, but their risks are well documented. Depending on the drug, dose and patient, those risks can include nausea, constipation, sedation, respiratory depression, physical dependence and misuse.

Postoperative prescriptions can also become a patient’s first exposure to opioids. That does not mean everyone who receives a short-term prescription will develop a problem, nor does this study suggest that doctors should stop prescribing opioids when they are medically appropriate. It does mean that a safe and effective non-opioid alternative could reduce unnecessary exposure and give physicians more options.

This is why a direct comparison between CBD and codeine-acetaminophen is so valuable. Much of the public discussion surrounding CBD and pain has been based on consumer reports, observational evidence or studies involving chronic pain. A randomized human trial examining acute postoperative pain moves the conversation forward.

What This Study Does—and Does Not—Prove

The findings are promising, but they should be viewed in context.

First, the trial included only 35 adults. The crossover design strengthens the comparison, but the sample remains small. Larger, multicenter studies would help determine whether the results hold across a broader and more diverse population.

Second, the study focused specifically on pain after PRK eye surgery. It did not test CBD following abdominal surgery, joint replacement, dental procedures or every other form of acute pain.

Third, the study tested a defined dose and formulation. CBD products can differ dramatically in concentration, cannabinoid profile, manufacturing quality and labeling accuracy. A favorable result for one clinical formulation is not an endorsement of every commercially available CBD product.

Finally, patients should not replace prescribed pain medication with CBD without speaking to a qualified healthcare professional. Postoperative pain can sometimes signal a complication, and any treatment plan should account for a person’s medical history, current prescriptions and surgical instructions.

Florida Researchers Help Advance Cannabinoid Medicine

The University of Florida connection makes this research particularly relevant to patients and cannabis advocates across the Sunshine State. Florida is home to one of the nation’s largest medical cannabis populations, yet federal restrictions and decades of prohibition continue to complicate cannabinoid research and medical education.

Studies like this demonstrate why cannabis policy should be guided by evidence rather than stigma. When researchers are able to test standardized cannabinoid formulations against conventional medications, patients and doctors gain information that prohibition-era assumptions could never provide.

The responsible response is not to declare CBD a miracle drug. It is to support rigorous research, honest labeling, physician education and policies that make scientifically sound cannabis studies easier to conduct.

A Promising Step Toward Opioid-Sparing Pain Care

This clinical trial does not settle the entire debate over CBD and pain. It does, however, offer compelling preliminary evidence that a low-THC oral CBD formulation can provide pain relief comparable to codeine-acetaminophen after PRK eye surgery.

That is a meaningful result. If larger trials confirm it, cannabinoid-based medicines could eventually give some surgical patients an effective pain-management option with fewer of the risks associated with opioids.

For Suncoast NORML, the broader lesson is clear: cannabis and cannabinoids deserve to be researched like medicine, regulated with honesty and discussed without the baggage of prohibition. Patients benefit when policy makes room for science.

Frequently Asked Questions

Can oral CBD relieve pain after eye surgery?

In this randomized trial, a standardized low-THC oral CBD formulation provided pain control comparable to codeine-acetaminophen after PRK laser eye surgery. More research is needed before the finding can be applied broadly.

Was CBD more effective than the opioid medication?

No. Researchers found no significant difference in average or maximum pain ratings. The treatments produced comparable pain control in this small study.

What dose of CBD did the researchers test?

Participants received a low-THC oral CBD formulation at 50 milligrams twice daily. This was a controlled research product, so readers should not assume that any retail CBD product will produce the same result.

Does this mean patients should replace prescribed opioids with CBD?

No. Patients should follow their surgeon’s instructions and discuss CBD with a qualified healthcare professional before changing any medication. CBD may interact with other drugs, and postoperative pain sometimes requires medical evaluation.

Did the CBD treatment affect surgical recovery or vision?

The study reported similar recovery outcomes under both treatments. Visual acuity improved by the three-month follow-up, with no treatment-related difference between CBD and codeine-acetaminophen.

Sources and Credit

This article was inspired by and credits National NORML’s original report, “Clinical Trial: Oral CBD Mitigates Post-Surgery Ocular Pain as Effectively as Opioids”.

Read the peer-reviewed study abstract: “Randomized, Controlled Cross-over Comparison of Oral Cannabidiol to Oral Opioid for Postoperative Photorefractive Keratectomy Pain Control” in the Journal of Cataract & Refractive Surgery. DOI: 10.1097/j.jcrs.0000000000002030.

Medical disclaimer: This article is for educational and informational purposes only. It is not medical advice and should not be used to diagnose, treat or replace guidance from a licensed healthcare professional. Consult your physician before using CBD, especially following surgery or while taking other medications.