Nitric oxide levels of aqueous humor after photorefractive keratectomy


Adiguzel U., Bilgihan K., Ozdek Ş., Sancak B., Hasanreisoglu B.

EUROPEAN JOURNAL OF OPHTHALMOLOGY, vol.14, no.2, pp.100-105, 2004 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 2
  • Publication Date: 2004
  • Doi Number: 10.1177/112067210401400203
  • Journal Name: EUROPEAN JOURNAL OF OPHTHALMOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.100-105
  • Gazi University Affiliated: Yes

Abstract

PURPOSE. To measure the nitric oxide (NO) levels of aqueous humor in rabbits after photorefractive keratectomy (PRK) and to evaluate the alterations of NO levels according to the PRK surgery steps, ablation depth, and time. METHODS. Fifty eyes of 25 New Zealand white rabbits were included in the study. One eye was later randomly excluded from the study in order to equalize the number of eyes in groups. Eyes were divided into seven groups, each comprising seven eyes: unwounded control (Group 1), epithelial scrape (Group 2; aqueous humor samples taken at the 4th hour), superficial PRK (Group 3; samples taken at the 4th hour), deep PRK (Group 4; samples taken at the 4th hour), epithelial scrape (Group 5; samples taken at the 24th hour), superficial PPK (Group 6; samples taken at the 24th hour), and deep PPK (Group 7; samples taken at the 24th hour). The corneal epithelium was mechanically removed in surgical groups. The authors performed superficial corneal ablation (59 mum) in Groups 3 and 6 and deep corneal ablation (99 mum) in Groups 4 and 7. Aqueous humor samples were taken at the 4th hour (Groups 2-4) or 24th hour (Groups 5- 7) after corneal surgeries. NO measurements were performed indirectly by using the Griess reaction with a spectrophotometer. RESULTS. Aqueous humor NO levels 4 hours after Corneal surgery were statistically significantly lower than the control group (p<0.05). However, there was no difference among the surgical groups at the 4th hour (p>0.05). At the 24th hour, the deep PRK group had significantly lower NO levels than both the control group and Groups 5 and 6 (p<0.05). NO levels were normalized at the 24th hour in epithelial scrape and superficial PRK groups (p<0.05) but remained stable at lower levels in (Jeep PPK groups (p<0.05). CONCLUSIONS. Corneal surgery caused low NO levels in aqueous humor 4 hours after surgery. However, 24 hours after surgery, NO levels normalized following epithelial scrape and superficial PRK and were stable at lower levels in the deep PRK group. Complications of deep PPK application are possibly induced by low NO existence in the aqueous humor. (Eur J Ophthalmol 2004; 14: 100-5)