Surgical Team Offers Pupillary Membrane Protocol

For patients with hyperplastic persistent pupillary membranes covering the visual axis, surgical intervention may not result in significant complications with early intervention, according to study results published in BMC Ophthalmology. Results also suggested that prompt visual rehabilitation, besides deprivation with patching, may lead to the most optimal visual prognosis in patients associated with risk of ametropic and strabismic amblyopia. 

Although persistent pupillary membranes may affect up with 95% of newborns, the congenital abnormality does not significantly influence visual development, as regression is most often completed within the first year of life; however, fine diaphanous remnants can be found at the pupillary margin in older children and adults. In cases where the persistent pupillary membranes are centrally located and thick or heavily pigmented, intervention including pharmacologic therapy and surgery may be necessary. 

As other congenital abnormalities may be linked to persistent pupillary membranes, a group of investigators conducted a retrospective, interventional case series study (IRB number, CMHU109-REC2-069) at China Medical University Hospital to determine the long-term visual prognosis and complications associated with early surgical intervention and timely visual rehabilitation in patients with dense persistent pupillary membranes and other related abnormalities. 

The researchers retrospectively reviewed patients younger than 4 years who underwent surgical intervention of thick persistent pupillary membranes with other amblyopic risk factors or ocular abnormalities. All patients underwent preparation for cataract surgery, as underlying cataract and anterior lens capsule damage during surgery were possible. Visual rehabilitation programs commenced as soon as patients were “suitable” and continued until visual acuity was stable. 

The surgical techniques employed varied, according to the investigators, who suggested using “‘cataract-extraction-like’ incision wounds,” in other words, a single 2.2 mm main wound with another smaller side port incision. “The advantage is pediatric surgeons are familiar with this intraocular operation setting because it is the same as in cataract surgery. Further, much more working space can be achieved compared with a single entry. The most important advantage compared with single port entry is if an underlying cataract is discovered during the operation, sequential cataract operations can be done without changing wound settings. As for separating the PPM from the iris, vitrectors, vitrectomy scissors, and intraocular scissors are all recommended instruments,” according to the report.

A total of 5 patients (7 eyes) were included in the analysis; 3 patients were boys, 2 were girls. The mean age at baseline was 33.9 months, and the mean age at time of surgery was 42.3 months.   

Ocular abnormalities included inferior oblique overaction of both eyes, exotropia, and severe astigmatism in patient 1, severe astigmatism in patient 2, right eye keratoconus in patient 3, large optic nerve coloboma of both eyes in patient 4, and severe anisometropia in patient 5. As 3 patients were too young for viable results, visual acuity before surgery assessed in 4 eyes of 2 patients was0.54 logMAR. 

The average follow-up period was 4.9 years and the best-corrected visual acuity was a logMAR of 0.29 upon final visit with an average refractive error of -5.46 D. 

Iris strands were removed and visual axes were cleared successfully in all patients. The investigators did not observe any intraoperative complications; however, slight bleeding occurred when iris strands were cut but this stopped spontaneously.   

Most favorable outcomes were observed in cases with only refractive errors as associated ocular abnormalities, although cases with high astigmatism had favorable outcomes as well. Conversely, highly myopic cases had less favorable final best-corrected visual acuity (all <0.18 logMAR). 

“Besides patching, early [persistent pupillary membrane] intervention and timely visual rehabilitation achieve the best visual prognosis in patients associated with risks of ametropic and strabismic amblyopia,” according to investigators. We suggest early intervention and timely visual rehabilitation to achieve the best vision prognosis in patients with significant persistent pupillary membrane.”

Reference 

Huang YT, Lin HJ. Long term surgical outcome for persistent pupillary membranes with associated ocular abnormalities: a retrospective case series study. BMC Ophthalmol. 2021;21(1):232. doi:10.1186/s12886-021-01990-8