Medicine prides itself on being evidence-based, and yet every specialty harbors beliefs that persist long after the evidence supporting them has faded – or never even existed in the first place. Ophthalmology is no exception.

What makes these myths particularly fascinating is not simply that they are incorrect, but that they continue to influence everyday clinical decisions despite increasingly robust data to the contrary. Most of these myths did not arise from poor science. Rather, they originated from logical physiological assumptions, expert opinion, isolated case reports, or historical practice patterns that gradually became accepted as unquestionable truths. Once incorporated into residency training, textbooks, and routine practice, they proved remarkably resistant to change.

This problem is not merely academic. Every outdated belief in medicine has consequences: unnecessary patient anxiety, avoidance of effective treatments, additional healthcare costs, cumbersome postoperative restrictions, and sometimes even preventable harm.

Several examples illustrate how difficult it can be for evidence to overturn clinical tradition.

Consider the long-standing teaching that intravenous mannitol is ineffective in vitrectomized eyes because its mechanism depends on shrinking the vitreous. It is an elegant explanation – but an incomplete one. Clinical studies now demonstrate that mannitol continues to lower intraocular pressure effectively after vitrectomy, indicating that additional mechanisms, including reduced aqueous production and enhanced uveoscleral outflow, contribute significantly to its action (1). Patients with acute postoperative pressure elevation should not be denied an effective therapy simply because an old physiological model seemed convincing at the time.

A similar story exists in pediatric refraction. Cyclopentolate has long been regarded as the indispensable cycloplegic agent for children, while tropicamide has often been viewed as insufficient. Yet comparative studies repeatedly show that tropicamide provides remarkably similar refractive measurements while offering substantial practical advantages: shorter recovery, less photophobia, improved tolerability, and reduced disruption of school and family life (2). Sometimes the "stronger" option is not necessarily the "better" option.

Perioperative aspirin management offers another striking example. Despite overwhelming evidence that continuing aspirin during routine cataract surgery does not meaningfully increase the risk of vision-threatening hemorrhage, many surgeons continue recommending discontinuation (3). The irony is obvious: while the ocular bleeding risk is largely theoretical, the systemic thrombotic risk of stopping aspirin is well established. Similar misconceptions have historically extended to vitreoretinal surgery. Contemporary evidence supports the safety of continuing aspirin in appropriately selected patients undergoing vitreoretinal procedures, reinforcing the principle that evidence should outweigh habit when balancing ocular and systemic risks (4).

Perhaps no group of medications has suffered more from reputation than prostaglandin analogues. For years, ophthalmologists have hesitated to prescribe these highly effective glaucoma medications because of concerns regarding cystoid macular edema (CME) and uveitis. Both concerns originated from plausible biological hypotheses and scattered case reports. Yet large observational studies and modern evidence consistently fail to demonstrate a clinically meaningful increase in either complication (5, 6). Nevertheless, these concerns continue to influence prescribing habits, depriving many patients – particularly those with uveitic glaucoma – of one of our most effective classes of intraocular pressure-lowering medications.

Postoperative face-down positioning after macular hole surgery represents another tradition ripe for reconsideration. Generations of retinal surgeons instructed patients to remain face down for prolonged periods, often for a week or longer. The burden on elderly patients and caregivers is substantial, affecting mobility, sleep, nutrition, and quality of life. Yet randomized studies increasingly suggest that less restrictive positioning achieves comparable anatomical success in many patients, particularly those with smaller macular holes (7). While individual cases still require tailored recommendations, the universal prescription of prolonged face-down positioning deserves critical reassessment.

Laser peripheral iridotomy provides another lesson in how intuitive reasoning can become dogma. Superior placement has traditionally been favored under the assumption that the upper eyelid would reduce dysphotopsia. It seems anatomically reasonable. However, studies examining patient-reported outcomes have failed to confirm any consistent advantage of superior placement, with some even suggesting that temporal iridotomies may offer superior patient comfort (8). Once again, plausible anatomy has proven to be a poor substitute for clinical evidence.

Even outside ophthalmology clinics, myths continue to shape patient counselling. One persistent misconception is that vaginal delivery increases the risk of retinal detachment in women with high myopia or previous retinal pathology (9). This belief has led to unnecessary obstetric referrals and even cesarean deliveries based solely on ocular history. However, modern ophthalmic and obstetric evidence demonstrates that spontaneous vaginal delivery does not increase retinal detachment risk in these patients (9). Despite repeated reassurance from the literature, outdated recommendations continue to circulate among both ophthalmologists and obstetricians.

These examples raise a broader question: why do myths survive?

The answer likely lies in how physicians learn. We remember vivid complications far better than reassuring cohort studies. A memorable case report often carries greater emotional weight than a meta-analysis involving thousands of patients. Expert opinion frequently becomes embedded in residency teaching before definitive evidence emerges. Once a practice becomes routine, changing it requires more than publishing a paper – it requires changing habits, educational curricula, and institutional culture.

Confirmation bias also plays a powerful role. We naturally notice cases that reinforce existing beliefs while overlooking the many patients who contradict them. Every episode of postoperative inflammation in a patient receiving prostaglandin therapy becomes memorable, whereas the thousands of uneventful cases quietly fade into the background.

Evidence-based medicine is not simply about generating new evidence; it is equally about abandoning outdated ideas when better evidence becomes available. This process – sometimes called “medical de-implementation” – is arguably one of the greatest challenges in modern healthcare. Stopping an unnecessary practice often proves harder than adopting a new one.

Perhaps the greatest lesson from these myths is one of humility. Today's certainty may become tomorrow's misconception. As clinicians, we should remain willing to question even our most deeply held assumptions. After all, progress in medicine depends not only on discovering new treatments but also on having the courage to let go of old beliefs that no longer withstand scientific scrutiny.

The best ophthalmologists are not those who never change their minds – they are those who change them when the evidence demands they do so.