Objective assessment of graft clarity and recurrence after penetrating keratoplasty for granular, lattice and macular corneal dystrophy using scheimpflug densitometry

Abstract

Purpose To evaluate long-term outcomes and recurrence patterns following penetrating keratoplasty (PKP) in granular (GCD), lattice (LCD), and macular corneal dystrophy (MCD), using Scheimpflug-based corneal densitometry (grayscale units–GSU) as an objective tool to assess graft clarity.

Methods In this retrospective single-center study, 99 eyes of 59 patients with GCD (n = 38), LCD (n = 30), or MCD (n = 31) were analyzed. A total of 112 PKPs, including 74 excimer laser-assisted PKPs, were evaluated. Clinical examinations included visual acuity, slit-lamp evaluation, and corneal tomography using the Pentacam HR. Clinical recurrence was defined as the appearance of dystrophy-specific changes within the graft. Corneal densitometry was assessed in the anterior, central, and posterior layers and the total corneal thickness at 0–2 mm and 2–6 mm zones. Follow-up ranged from 6 weeks to more than 5 years (5y+) postoperatively.

Results A significant postoperative improvement in BCVA was observed in eyes with GCD and MCD, with sustained visual gains up to 4y and 5y postoperatively, respectively. GCD demonstrated the earliest and highest clinical recurrence rate, with all grafts affected by 5y. LCD showed delayed recurrence from 4y onward, while MCD did not show any recurrence within 5y. Corneal densitometry revealed a progressive increase in GSU in GCD and LCD, particularly in the anterior (GCD:5y / LCD:5y+) and central layers (GCD:4y / LCD:5y+). MCD showed stable GSU values throughout follow-up. Linear regression analysis showed the strongest GSU increase in LCD (slope = 1.65, R²=0.47) and GCD (slope = 0.94, R²=0.14), particularly in the anterior 0–2 mm zone. MCD showed minimal change across all layers and diameters.

Conclusion Scheimpflug-based corneal densitometry enables objective, layer-specific monitoring of graft clarity and recurrence after PKP. Recurrence rates differ significantly among dystrophy subtypes, highlighting the clinical utility of densitometry in tailoring follow-up strategies, particularly in GCD and LCD with high risk of recurrence.