Clinical efficacy of combined treatment of pellucid marginal degeneration

Abstract

Purpose. The analysis of clinical efficacy of combined treatment of pellucid marginal degeneration (PMD), which included the implantation of intrastromal corneal ring segments (ICRS) and corneal collagen crosslinking (CXL).Material and methods. The analysis of results in the treatment was carried out in 12 eyes of 7 patients with PMD. A quantity and characteristic parameters of the implantable ICRS were determined using the own method of calculation based on keratotopography data. After 3 months, the procedure of local CXL was performed. The follow-up period was 1 year. In the process of observation the parameters of uncorrected (UCVA) and best corrected (BCVA) visualacuity, spherical equivalent and cylindrical component of subjective refraction were examined on the 1st day, 3 and 12 months after the start of treatment. At the same time the keratotopography data were analyzed – the cylindrical component and maximum keratometry and their dynamics. Keratopachymetry and endothelial cell density were examined before treatment, and 3 and 12 months after the treatment.Results. On the 1st day after the ICRS implantation, the refractive effect of operation varied from 7.0 to 10.5D (mean 7.6±2.1). A slightly decrease of refractive effect, which did not affect the functional results, was noted 3 months after operation before CXL. After CXL at the end of the follow-up period, the refraction of the cornea remained stable. An UCVA increase compared with the baseline by an average of 0.28±0.09, and for BCVA – by 0.09±0.05 was observed already on the 1st day after the ICRS implantation. One year after beginning of treatment, the UCVA increased by 0.32±0.18, BCVA – by 0.32±0.11 and amounted respectively 63.5±17.3% and 83.8±12.5% of retinal visual acuity before the treatment. At the same time, the parameters of keratopachymetry and endothelial cell density practically did not change after the performed treatment.Conclusion. The performed analysis showed a high efficiency and a safety of the combined treatment of PMD in the correction of refractive disorders, characteristic for this disease that allowed an increase in visual acuity of operated eyes and to ensure their stability for 1 year of follow-up period. Long-term results of proposed method require a further study.

Keywords

• intrastromal corneal ring segments
• pellucid marginal degeneration
• keratotopography
• corneal collagen cross-linking