Tropicamide may be more suitable for cycloplegic refraction vs. cyclopentolate
Key takeaways:
- Cyclopentolate and tropicamide had comparable refractive error values across four studies.
- Tropicamide may be preferable for cycloplegic refraction due to its ideal characteristics.
Cyclopentolate 1% and tropicamide 1% had similar efficacies for cycloplegic refraction in youth and adults without strabismus, according to a study.
Such findings “have significant implications in clinical and epidemiological contexts” and may support tropicamide’s use, the study authors noted.
“Cyclopentolate 1% is the drug of choice for cycloplegic refraction; however, it has potential adverse reactions such as headache, dizziness and restlessness,” Jeewanand Bist, MOptom, of the Tilganga Institute of Ophthalmology in Nepal, told Healio. “In addition, more serious side effects such as hallucinations, fainting and altered perceptions are also frequently encountered.”
Tropicamide has a safe profile, rapid onset and a shorter duration of action, all ideal characteristics for a cycloplegic drug, Bist and colleagues wrote in Optometry and Vision Science. Yet, “the depth of cycloplegia of tropicamide has been a matter of controversy. This has led to many clinicians preferring cyclopentolate over tropicamide for full cycloplegia.”
Prior research has indicated “that the refractive error post-cycloplegia with tropicamide is comparable to that with cyclopentolate in healthy nonstrabismic subjects,” so Bist and colleagues aimed to confirm these findings in a systematic review and meta-analysis in which they assessed four randomized controlled trials conducted between 1993 and 2024. The analysis was composed of 171 eyes of 171 participants, aged 4 months to 50 years, in each group.
There were no statistically significant differences in mean spherical equivalent refractive error values between the two groups. There was also no heterogeneity seen between the studies, and the primary outcome did not change when only children were included in the meta-analysis.
Bist and colleagues wrote that all the studies “were well conducted,” but only one analysis was judged to have a low risk of bias across all seven domains of assessment.
There were multiple study limitations. For example, there was a small number of randomized controlled trials on this topic. If more trials, particularly those with larger sample sizes, had been available to evaluate, “it would have strengthened the message of the present review,” the researchers wrote.
“Another limitation of our review is that our results are valid for nonstrabismic healthy subjects,” they wrote. “In this meta-analysis, we did not evaluate the effect of interventions in strabismic patients.”
Bist and colleagues explained that despite the comparable determination of refractive error between cyclopentolate and tropicamide, cyclopentolate is a poorer dilator and has a longer duration of action vs. tropicamide.
These downsides of cyclopentolate “bring on visual difficulties in patients for a few days post-cycloplegia, particularly in schoolchildren who cannot perform their near tasks for a longer duration,” they wrote.
Therefore, these data “provide important evidence for using a safer and shorter-acting drug” in tropicamide 1% for cycloplegic refraction in nonstrabismic patients, they said.
They added that “further randomized controlled trials, particularly in children, are still warranted to validate our findings.”
Bist explained the impetus behind this research: “During my clinical practice as an optometrist, I encountered many children who showed serious adverse reactions when using cyclopentolate 1%, which made me reluctant to use this drug unless otherwise strongly indicated. I often used tropicamide 1% in nonstrabismic children because there were few primary studies that showed similar efficacies between the two drugs.
“During my practice, surprisingly, I also encountered many eye care practitioners who did not even consider tropicamide as a cycloplegic drug, particularly in the developing countries. This led to me conceptualizing this review, which we were finally able to publish.”
Editor’s note: This article was updated March 22, 2025, to add comments from Bist.
Perspective
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As an optometrist specializing in pediatric and custom contact lenses, I have long been accustomed to using 1% cyclopentolate to examine infants and children in my practice. A good retinoscopy in a dark room frequently tells me most of what I need to know without any pharmacological interference with the accommodative system. The purpose of cycloplegia in these examinations is:
- to stabilize the accommodation and make it easier to obtain a stable reflex for proper assessment before reaching a final prescription;
- to tease out residual amounts of hyperopia, especially in hyperopic and strabismic children who have an accommodative component to their esotropia; and
- to examine the fundus through a dilated pupil.
This meta-analysis confirms that for nonstrabismic patients, there is no clinically significant difference in refractive outcome between 1% tropicamide and 1% cyclopentolate. Tropicamide is also a more effective dilating agent with a much shorter duration of action and faster recovery compared with cyclopentolate. While I agree that for adults, most myopic children, most low hyperopes and nonstrabismic patients, this is true, nonetheless I have come across many cases in my 30-plus-year career in which a child brought for a second opinion is found to be significantly (more than 1.5 D) more hyperopic than in prior dilated examinations in which only tropicamide was used.
The takeaway for the primary eye care provider is that one must use sound clinical judgment when ordering tests. A cookbook approach is never ideal. Remember that whichever drop one chooses, optimal effect still takes a full 30 minutes for both, and while 1% tropicamide usually wears off in 3 to 4 hours, it can last up to 24 hours. If a child or adult presents with strabismus or headaches and the clinician suspects an accommodative component is involved, some form of cycloplegia is indicated, and for most nonstrabismic patients, that choice can be 1% tropicamide. However, if strabismus is present, cyclopentolate is still a useful tool in the diagnostic arsenal.
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