Pluronic polyol: A potential alloplastic keratorefractive material

Abstract

Pluronic polyol possesses a negative temperature coefficient of gelation; it is liquid at low temperatures and gelatinous at high temperatures. Pluronic F108 was evaluated as a potential material for alloplastic keratorefractive surgery: 0.3 ml of the material in a liquid state was injected into a surgically prepared axial 7 mm mid-stromal corneal bed in 17 rabbits; fellow eyes in the rabbits were sham-operated but not injected. Postoperatively, rabbits were clinically evaluated with biomicroscopy, keratometry, and pachymetry at regular intervals up to three months following surgery. Animals were periodically sacrificed and corneas were studied by light and electron microscopy. The material appeared to be well tolerated by the cornea. Both control and pluronic eyes showed an initial increase in corneal thickness peaking at one week postoperatively, with return to near normal levels by the end of the third week. Refractive flattening of approximately three diopters was noted in the experimental group, while no change was seen in the control group.

Safety Assessment of Poloxamers 101, 105, 108, 122, 123, 124, 181, 182, 183, 184, 185, 188, 212, 215, 217, 231, 234, 235, 237, 238, 282, 284, 288, 331, 333, 334, 335, 338, 401, 402, 403, and 407, Poloxamer 105 Benzoate, and Poloxamer 182 Dibenzoate as Used in Cosmetics

“…Poloxamer 338 Kim et al (1988) investigated a 25% w/w aqueous solution of Poloxamer 338 for potential use as an alloplastic keratorefractive material. Keratorefractive procedures involve surgical alteration of the cornea to change the refractive power and improve visual acuity; this study tested Poloxamer 338 in rabbits in hopes of its use in humans.…”

“…The authors reported that, despite initial scarring and other issues, the Poloxamer was well tolerated by the end of 3 months and may be of use in keratorefractive surgery. They did not find a well-defined disc of material upon examination of treated eyes and suggest that they did not achieve adequate gelation of the material and the Poloxamer may have been phagocytized by keratocytes or resorbed throughout the stroma (Kim et al 1988).…”