T Riedel1, B Seitz, A Langenbucher, G O Naumann. 1. Augenklinik mit Poliklinik, Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen. tobias.riedel@augen.imed.uni-erlangen.de
Abstract
OBJECTIVE: Due to unfavourable optical and immunological conditions, an eccentric position of the corneal transplant is limited to curative or tectonic indications. The purpose of this study was to assess the morphological results of eccentric homologous penetrating keratoplasty (PK) with respect to diagnosis as well as position and size of the corneal graft. PATIENTS AND METHODS: In our retrospective study, 122 cases of eccentric homologous PK in 96 eyes between 01/1989 and 10/1997 were included, which in 104 patients was necessary because of a corneal ulcer (36 previous PK, 21 areactive/rheumatic, 20 herpetic, 15 bacterial, 12 other). Elective PK was performed on 6 eyes with corneal scars, 7 eyes with ectatic corneal diseases (ECT) and 5 others. Using postoperative slides the following parameters were quantified: the graft diameter (GD) and transparency, the distance of the geometric centre of the cornea from the central trephination margin (ABS) as well as from the geometric centre of the graft (decentration, DEZ). Of these, 17 grafts were classified as eccentric peripheral keratoplasty (EPK) with the optical axis through the host cornea and 67 as eccentric central keratoplasty (ECK) with the optical axis through the graft. RESULTS: The average follow-up period was 25 months. In EPK (ulcers only, 5.0 +/- 1.7 mm) the mean GD was significantly lower than in ECK (78% ulcers, 7.0 +/- 1.3 mm) (p < 0.001). The decentration of EPK (3.5 +/- 1.1 mm) was significantly higher than for ECK (1.4 +/- 0.8 mm, p < 0.001). ABS of EPK was +1.3 +/- 0.9 mm and for ECK was -2.0 +/- 1.0 mm. Of the grafts in EPK and ECK 46%/57%, respectively were crystal clear, 18%/15% respectively showed minor decompensation and 36%/28% were completely cloudy. In cases of ulcers/scars/ECT/others, 45%/75%/100%/75% were crystal clear, respectively, 18%/25%/0%/0% showed minor decompensation and 37%/0%/0%/25% were completely cloudy. With increasing stages of cloudiness, the mean graft decentration increased from 1.4 +/- 1.1 mm (crystal clear) to 1.7 +/- 1.2 mm (minor decompensation) and 2.2 +/- 1.4 mm (completely cloudy). Transplants with greater GD (p = 0.04) and ABS (p = 0.01) were significantly more often clear. Ulcers were significantly more cloudy than scars/ECT (p < 0.01). The position of the graft and its cloudiness was not significantly correlated. CONCLUSION: The diagnosis leading to eccentric PK seems to have the greatest impact on long-term graft transparency. Our results indicate that an increasing decentration of the graft is not inevitably associated with an increasing probability of clouding. A central penetrating repeat keratoplasty may be considered in the non-inflamed interval after eccentric tectonic mini-keratoplasty.
OBJECTIVE: Due to unfavourable optical and immunological conditions, an eccentric position of the corneal transplant is limited to curative or tectonic indications. The purpose of this study was to assess the morphological results of eccentric homologous penetrating keratoplasty (PK) with respect to diagnosis as well as position and size of the corneal graft. PATIENTS AND METHODS: In our retrospective study, 122 cases of eccentric homologous PK in 96 eyes between 01/1989 and 10/1997 were included, which in 104 patients was necessary because of a corneal ulcer (36 previous PK, 21 areactive/rheumatic, 20 herpetic, 15 bacterial, 12 other). Elective PK was performed on 6 eyes with corneal scars, 7 eyes with ectatic corneal diseases (ECT) and 5 others. Using postoperative slides the following parameters were quantified: the graft diameter (GD) and transparency, the distance of the geometric centre of the cornea from the central trephination margin (ABS) as well as from the geometric centre of the graft (decentration, DEZ). Of these, 17 grafts were classified as eccentric peripheral keratoplasty (EPK) with the optical axis through the host cornea and 67 as eccentric central keratoplasty (ECK) with the optical axis through the graft. RESULTS: The average follow-up period was 25 months. In EPK (ulcers only, 5.0 +/- 1.7 mm) the mean GD was significantly lower than in ECK (78% ulcers, 7.0 +/- 1.3 mm) (p < 0.001). The decentration of EPK (3.5 +/- 1.1 mm) was significantly higher than for ECK (1.4 +/- 0.8 mm, p < 0.001). ABS of EPK was +1.3 +/- 0.9 mm and for ECK was -2.0 +/- 1.0 mm. Of the grafts in EPK and ECK 46%/57%, respectively were crystal clear, 18%/15% respectively showed minor decompensation and 36%/28% were completely cloudy. In cases of ulcers/scars/ECT/others, 45%/75%/100%/75% were crystal clear, respectively, 18%/25%/0%/0% showed minor decompensation and 37%/0%/0%/25% were completely cloudy. With increasing stages of cloudiness, the mean graft decentration increased from 1.4 +/- 1.1 mm (crystal clear) to 1.7 +/- 1.2 mm (minor decompensation) and 2.2 +/- 1.4 mm (completely cloudy). Transplants with greater GD (p = 0.04) and ABS (p = 0.01) were significantly more often clear. Ulcers were significantly more cloudy than scars/ECT (p < 0.01). The position of the graft and its cloudiness was not significantly correlated. CONCLUSION: The diagnosis leading to eccentric PK seems to have the greatest impact on long-term graft transparency. Our results indicate that an increasing decentration of the graft is not inevitably associated with an increasing probability of clouding. A central penetrating repeat keratoplasty may be considered in the non-inflamed interval after eccentric tectonic mini-keratoplasty.