Localized RPE Removal with a Novel Instrument Aided by Viscoelastics in Rabbits.
OBJECTIVE
We developed a surgical method for localized and atraumatic removal of the retinal pigment epithelium (RPE) with a novel instrument.


METHODS
Bleb retinal detachments (bRD) were raised with balanced salt solution (BSS) following vitrectomy in 27 rabbits. The RPE was scraped with 3 loop variants (polypropylene [PP], 0.1 mm; PP, 0.06 mm; metal, 0.1 mm) of a custom-made instrument. Stabilization of bRDs with BSS or various concentrations (0.1%-0.5%) of hyaluronic acid (HA) was video analyzed. Perfusion-fixed samples of scraped areas and controls were studied by light and transmission electron microscopy.


RESULTS
The bRDs were sufficiently stabilized by ≥0.25% HA. Using the PP 0.1 mm loop with a single forward/backward stroke, an area of ca. 2.5 × 1.5 mm was nearly devoid of RPE, yet did show occasional Bruch's membrane (BM) defects combined with choriocapillaris hemorrhages in 13% of the bRDs. A single scrape with PP 0.06 mm resulted in unsatisfactory RPE denudement, while repeated scraping maneuvers caused more BM defects and hemorrhages. The metal loop resulted in incomplete RPE removal and massive intraoperative subretinal hemorrhages. Histologically, intact photoreceptor outer segments (POS) were observed above the RPE wounds in bRDs. Controls with bRDs alone showed an intact RPE monolayer with microvilli, with few engulfed remains of POS.


CONCLUSIONS
Localized removal of RPE in HA stabilized bRD can be achieved by a PP 0.1 mm loop instrument.


CONCLUSIONS
Removal of degenerated RPE may aid RPE cell replacement strategies.
Department of Ophthalmology, University of Bonn, Bonn, Germany.
Fabian
F
Thieltges
Department of Ophthalmology, University of Bonn, Bonn, Germany ; Present address: Zengping Liu, Department of Ophthalmology, National University of Singapore, Singapore.
Zengping
Z
Liu
Department of Ophthalmology, University of Bonn, Bonn, Germany.
Ralf
R
Brinken
Geuder AG, Heidelberg, Germany.
Norbert
N
Braun
Mettapracharak Eye Institute, Raikhing, Nakhon Pathom 73210, Thailand.
Warapat
W
Wongsawad
Mettapracharak Eye Institute, Raikhing, Nakhon Pathom 73210, Thailand.
Sudawadee
S
Somboonthanakij
Department of Ophthalmology, University of Bonn, Bonn, Germany.
Martina
M
Herwig
Department of Ophthalmology, University of Bonn, Bonn, Germany.
Frank G
FG
Holz
Department of Ophthalmology, University of Bonn, Bonn, Germany ; Present address: Singapore National Eye Center, Singapore.
Boris V
BV
Stanzel
AMD; Bruch's membrane; RPE transplantation; cell replacement; cell-based therapy; hyaluronic acid; hydrogel; retina; retinal surgery; tissue engineering