title: Long-Term Density Changes in Corneal Layers After Primary Pterygium Excision With Topical Mitomycin-C.
abstract: OBJECTIVE
  To evaluate the long-term change in average corneal densities at 18 months after primary pterygium excision with topical adjuvant mitomycin-C application, particularly the relationship between anterior and posterior corneal layer densities.
  
  
  METHODS
  Prospective observational case series. Patients were imaged with the Pentacam at 18 months after their surgery. Average corneal densities were the primary outcome and were compared with postoperative weeks 1, 4, and 12 data using paired t test.
  
  
  RESULTS
  In all, 31 eyes of 31 patients were recruited. Mean age at time of operation was 62.0 ± 9.4 years. Mean best-corrected logarithm of the minimal angle of resolution visual acuity at 18 months was 0.14. The mean total anterior, central, and posterior average corneal densities were 30.6, 25.9, and 20.5 respectively. Compared with postoperative week 1 data, the anterior layer was reduced by 12.7% (P = 0.0144); however, there was no significant change in the central and posterior layers (P = 0.5353 and 0.0858, respectively). Subgroup analyses did not support the use of a 10- to 12-mm annulus as opposed to total-diameter data, and density reduction effect at 18 months from week 12 and week 1 seemed to be stronger in males (P = 0.0074 and 0.0042, respectively).
  
  
  CONCLUSIONS
  Anterior corneal scars continued to diminish in density with time. Previous finding of a significant increase in posterior layer density at postoperative week 12 is likely not a result of optical phenomenon caused by a less dense anterior layer. Sex difference in terms of scar remodeling may be present.
authors.affiliation: *Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong; †Department of Ophthalmology and Vision Science, University of Arizona, Tucson, AZ; and ‡Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Ka Wai
authors.initials: KW
authors.lastname: Kam
authors.forename: Rachel P W
authors.initials: RP
authors.lastname: Kwok
authors.forename: Michael W
authors.initials: MW
authors.lastname: Belin
authors.forename: Alvin L
authors.initials: AL
authors.lastname: Young
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000477:Alkylating Agents / Q000627:therapeutic use*; D002452:Cell Count; D003131:Combined Modality Therapy; D003315:Cornea / Q000473:pathology*; D003720:Densitometry; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000627:therapeutic use*; D009883:Ophthalmic Solutions; D013508:Ophthalmologic Surgical Procedures; D011446:Prospective Studies; D011625:Pterygium / Q000503:physiopathology* / Q000601:surgery*
chemical_list: D000477:Alkylating Agents; D009883:Ophthalmic Solutions; D016685:Mitomycin