Incidence and quantification of corneal haze by Pentacam Scheimpflug densitometry following photorefractive keratectomy for myopia in virgin and post corneal transplant eyes with dark irides

Abstract

Purpose: To assess the incidence and quantification of corneal haze after myopic photorefractive keratectomy in virgin and post corneal transplant eyes with dark irides.

Methods: In this retrospective study at the tertiary eye hospital, the corneal haze was evaluated by slit-lamp and quantified by Pentacam Scheimpflug densitometry after myopic photorefractive keratectomy with mitomycin C in virgin eyes (group I) and post corneal transplant eyes (group II) with dark irides over 12 months.

Results: Group I compromised 126eyes from 77patients (35males and 42females) aged 31.31 years (24.11-36.18 years), and group II compromised 44eyes from 33patients (18males and 15females) aged of 32.25 years (26.15-36.66 years). The incidence of corneal haze was 9.5% (95%CI: 5.0%-16%) and 6.8% (95%CI: 1.4-18.7%) in group I and II respectively (P = 0.587). The corneal densitometry was 22.69 ± 8.28GSU preoperatively and 17.98 ± 3.13GSU at 12 months postoperatively (P = 0.010) in group I. The corneal densitometry was 21.86 ± 6.22GSU preoperatively and 21.23 ± 4.29GSU at 12 months postoperatively (P = 0.815) in group II. High corneal maximal densitometry was associated with the thin central corneal thickness (P = 0.027), the presence of haze (P = 0.028), post-keratoplasty (P = 0.004), steep keratometry (P = 0.035).

Conclusion: The incidence of corneal haze was comparable in virgin and post corneal transplant eyes. The Pentacam Scheimflug densitometry can be helpful in the diagnosis of corneal haze; however, the cutoff values need to be studied further in larger studies.

Keywords: Corneal haze; corneal transplant; myopia; photorefractive keratectomy; scheimpflug system.

Figure 1

Course of corneal densitometry over time in the group I and II

Figure 2

Receiver Operating Characteristic curve for corneal densitometry