Radial keratotomy: I. The wound healing process and measurement of incisional gape in two animal models using in vivo confocal microscopy

J. V. Jester, Walter M Petroll, W. Feng, J. Essepian, Harrison D Cavanagh

Research output: Contribution to journalArticle

76 Scopus citations

Abstract

Using in vivo confocal microscopy, corneal wound healing was evaluated in both rabbit and cat eyes after radial keratotomy. A total of six rabbit and six cat eyes were evaluated sequentially over time for 1 mo after surgery by in vivo confocal microscopy, and quantitative measurements of changes in incisional wound gape were determined. In vivo histopathologic changes were correlated with conventional histopathologic findings in 18 rabbit and 4 cat eyes; the animals were killed at various intervals from 0-30 days after surgery. In the rabbit, in vivo corneal wound healing was characterized by the initial ingrowth of corneal epithelium followed by persistence within the wound without a marked fibrotic response. Measurement of incisional wound gape showed increasing gape from 144 ± 32 μm on day 0 to 976 ± 155 μm on day 26 at a distance of 2.4 mm from the optical zone. These in vivo measurements were not significantly different (P = 0.996) from those obtained using conventional histopathologic techniques which showed an incisional wound gape of 252 ± 112 μm on day 0 and 917 ± 216 μm on day 26 at 2.5 mm from the optical zone. In the cat eyes, healing of radial keratotomy wounds showed an initial increase in incisional wound gape from 135 ± 56 μm on day 0 to 245 ± 88 μm on day 7 at a distance of 2.4 mm from the optical zone. Starting at day 14 and continuing to day 30, there was a progressive decrease in incisional wound gape from 198 ± 41 μm to 92 ± 35 μm. Sequential, in vivo histopathologic analyses indicated that increasing incisional wound gape correlated with the retention of corneal epithelium in the wound. Initiation of decreasing incisional wound gape was associated with replacement of the incisional epithelial plug with fibroblastic tissue. These changes in the incisional wound gape observed in the cat suggest that healing of radial keratotomy wounds involves contraction of the wound in response to the ingrowth of fibroblastic cells. Furthermore, the contractile response appears to be biphasic involving a precontractile and contractile phase. Overall these data indicated that in vivo confocal microscopy provides quantitative histopathologic data on living tissue comparable with that obtained with conventional techniques on dead, fixed, and sectioned tissue. Additionally, the absence of wound fibrosis in the rabbit radial keratotomy model raises important questions as to the appropriateness of this experimental model for human radial keratotomy.

Original languageEnglish (US)
Pages (from-to)3255-3270
Number of pages16
JournalInvestigative Ophthalmology and Visual Science
Volume33
Issue number12
StatePublished - Jan 1 1992

Keywords

  • confocal microscopy
  • corneal wound healing
  • light microscopy
  • myofibroblasts
  • radial keratotomy
  • refractive surgery

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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