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Results of a retrospective study show that simple congenital ptosis, even when the pupil is obstructed, is less amblyogenic than conventionally thought. The study supports correcting refractive error and strabismus before considering ptosis surgery.
Results of a retrospective review conducted to identify risk factors for amblyopia in patients with uncorrected congenital ptosis suggest the need to rethink conventional teaching about performing surgery early for congenital ptosis obstructing the visual axis in order to protect against amblyopia.
The study included 127 eyes of 112 patients, of which 17 eyes were amblyopic and 110 had normal vision. Compared with the group having normal vision, the amblyopic cohort had a higher incidence of pupil obstruction (76% vs. 60%) and significant refractive error (100% versus 29%). In multivariate analysis, however, only refractive error was an independent risk factor for amblyopia. Marcus Gunn jaw winking ptosis, strabismus, and unilateral ptosis were also not significant risk factors.
“We need to remember that ptosis correction in childhood requires general anesthesia and that up to one-third of patients will need repeat surgery,” said Roshmi Gupta, MD, Department of Oculoplastic Surgery, Narayana Nethralaya, Bangalore, India.
“Based on our study, we suggest that it is best to operate on those patients with congenital ptosis who are most likely to benefit. Therefore, refractive error and strabismus should be corrected before undertaking ptosis surgery. At our center, all patients with congenital ptosis are evaluated by the pediatric ophthalmology service and prescribed glasses, strabismus correction, and occlusion as appropriate. Then we proceed to surgery to correct ptosis only if the amblyopia is not improved after 2 to 4 months.”
Dr. Gupta and colleagues were motivated to undertake their study based on their experience seeing many adults with previously unoperated congenital ptosis who were requesting surgery for their ptosis and who were not amblyopic.
The cases were selected from patients seen between January 2012 and March 2016 and included individual with congenital ptosis with known vision and amblyopia status and accurate documentation of refractive error and strabismus assessment. Patients were excluded if they had a complex congenital ptosis, history of any ptosis surgery, or any other pathology that might cause poor vision.
In adults and older children, amblyopia was defined as visual acuity <6/12 in persons with bilateral ptosis or visual acuity 2 lines less than the better eye in cases with unilateral ptosis. The criteria in younger children were visual acuity below the age appropriate level with resistance to occlusion of the sound eye and an amblyogenic factor. Significant refractive error was defined as ≥-3 D myopia and ≥1.5 D of hypermetropia or astigmatism
Of the 112 patients, 97 had unilateral ptosis. The population had an average age of 18 years and included 9 patients aged 1 to 2 years. Ten patients (9%) had strabismus, 17 eyes (13.4%) were amblyopic, and 49 eyes (28%) had significant refractive error, with astigmatism being most common.
Dr. Gupta noted that the findings of the study seem to corroborate existing literature on the topic.
“Amblyopia has been associated with congenital ptosis in multiple studies. But when we went back to look at the papers that described improvement in or protection from amblyopia by correction of congenital ptosis, we found that the investigators selected their patients very carefully. In these studies, patients were being operated on only after management to eliminate strabismus and refractive error,” Dr. Gupta explained.
Roshmi Gupta, MD
This article was adapted from Dr. Gupta’s presentation at the American Academy of Ophthalmology. Dr. Gupta did not indicate any financial interest in the subject matter.