Study Shows Why Some Patients Misidentify Their Treatment Eye

The protocol of having a patient designate which eye is supposed to receive intravitreal injection is designed to be a safeguard against accidental injection into the wrong eye. If the patient identifies an eye that differs with the injecting physician’s records and the patient is correct, harm has been avoided. But, this approach could lead to potential redundancies in care if the patient is incorrect in their identification of the treatment eye. A recent study published in Retina sought to explain potential risk factors that could lead to patients incorrectly identifying their treatment eye before receiving intravitreal injections

Investigators found that patients with higher frequency of diabetic macular edema (DME) as the medical indication for treatment (P =.005); those who received a greater number of prior injections to the fellow eye (n = 6.7 ± 6.4; P =.03); patients who are receiving their first injection or patients who received their last injection more than year prior in the designated eye (P =.02) are most likely to incorrectly identify their treatment eye, or say that they don’t know which eye is to be treated. Patient history of intravitreal injections in the fellow eye over the past 6 months (P =.003), concurrent treatment of both eyes (P =.005) and possible language barriers (P =.05) also impact a patient’s likelihood of misidentifying the treatment eye.  

All study participants were consecutive patients who were referred by their treating retina specialist for intravitreal injection at the tertiary retina outpatient clinic of the Rambam Health Care Campus, Haifa, Israel, between June 2017 and November 2017. Overall, 91.4% of the 349 study participants correctly identified the eye intended for treatment; 1.4% identified the wrong eye; and 7.2% of patients did not know which eye was to be treated. 

If the potential risk factors are identified, then what can both practitioners and patients do to minimize the chance of incorrectly identifying the eye of treatment? Since patients receiving their first ever injection and those who experience more than a year between injections are more likely to falsely identify the eye intended for treatment, they need extremely thorough communication, the researchers said, explaining that, patients who misidentify their treatment eye “may not have been properly counseled or relayed their care plan effectively.”

Similar findings in prior research show that “when initiating new treatment, physicians often fail to communicate critical elements of proper medication use which contribute to misunderstandings of the treatment necessity and instructions of use, which in turn lead to patient failure to take medications appropriately,” the study explains.

“It seems that the physician and assisting staff should note that such patients may warrant a careful and prolonged explanation about the procedure and the laterality, to avoid potential errors and misunderstanding,” according to the researchers. 

The investigators also offer some suggestions, such as providing the patient with a sticker of their planned treatment eye in unilateral cases, and a treatment diary or log to outline the treatment schedule for each eye in either unilateral or bilateral cases. These strategies may help patients keep better track of their treatment plan. 

While the study’s authors point out that wrong-sided eye injections are rare, bilateral organs or structures are a “well-known potential source of interventional fault, not only for the patient but also for the treating team.” Proficient physician-patient communication is critical to reduce the risk of a patient incorrectly identifying the treatment eye and potentially leading to greater harm, the study shows 


Mimouni M, Ben Haim L,  Rozenberg E, et al. Self-designation of the treated eye before intravitreal injections: prevalence and predictors of incorrect calling. Retina. Published online August 18, 2020. doi: 10.1097/IAE.0000000000002956