biostudies-literatureGuasch FMNEI NIH HHSNational Eye Institute104105https://www.ebi.ac.uk/biostudies/studies/S-EPMC12090076biostudies-literatureUnknown29(1)We report the use of the Harms trabeculotome to facilitate 360° microcatheter advancement during illuminated microcatheter-assisted circumferential trabeculotomy (IMCT) ab externo in a 3-month-old infant with bilateral primary congenital glaucoma who required repeat surgery. The illuminated microcatheter was advanced 270°, from 9 to 6 o'clock; however, a focal blockage occurred, and, despite viscodilation, further advancement was not possible. The surgeon introduced a right Harms trabeculotome in the opposite direction, counterclockwise through the same scleral flap. The trabeculotome approximated and manipulated the illuminated microcatheter tip. The illuminated microcatheter was then able to advance beyond the focal obstruction, and the 360° circumferential trabeculotomy was completed.Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and StrabismusUse of Harms trabeculotome to assist failed microcatheter advancement during trabeculotomy in primary congenital glaucoma.PMC12090076K23 EY032525Thompson RGuasch FMLevin MRAlexander JLOula DWard SfalseUse of Harms trabeculotome to assist failed microcatheter advancement during trabeculotomy in primary congenital glaucoma.We report the use of the Harms trabeculotome to facilitate 360° microcatheter advancement during illuminated microcatheter-assisted circumferential trabeculotomy (IMCT) ab externo in a 3-month-old infant with bilateral primary congenital glaucoma who required repeat surgery. The illuminated microcatheter was advanced 270°, from 9 to 6 o'clock; however, a focal blockage occurred, and, despite viscodilation, further advancement was not possible. The surgeon introduced a right Harms trabeculotome in the opposite direction, counterclockwise through the same scleral flap. The trabeculotome approximated and manipulated the illuminated microcatheter tip. The illuminated microcatheter was then able to advance beyond the focal obstruction, and the 360° circumferential trabeculotomy was completed.2025-01-01T00:00:00Z2025 Feb2026-06-09T03:20:41.126Z2026-06-09T03:12:00.483ZS-EPMC120900763984843610.1016/j.jaapos.2025.104105