Comparison Of Visual And Topographic Outcomes Of Allograft And Synthetic Corneal Ring Segments

To analyze and compare the visual and topographic outcomes of keratoconus patients who underwent synthetic and allograft corneal ring implantation

Istanbul Medipol University Faculty of Medicine, Department of Ophthalmology

This retrospective study includes the visual and topographic results of keratoconic eyes treated with 55 allograft corneal rings and 27 synthetic corneal rings implantation. There was no difference between the two groups in terms of  demographic characteristics, visual acuity and topographic parameters preoperatively.  Uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), spherical refraction(SR), cylindrical refraction(CR), flat keratometry(K1), steep keratometry(K2), mean keratometry(Kmean), and maximum keratometry(Kmax) changes were calculated at 6 months postoperatively. The difference in topographic and visual results was compared between two groups.

At the postoperative 6th month, a flattening of the topographic findings and an increase in visual acuity were observed in both groups. Topographic flattening was not significantly different between the two groups. The increase in UCVA and CDVA was greater in the allograft group. (p=0.035 , <0.01 respectively) While there was no significant difference in SR changes, the change in CR was more in the synthetic group. (p=0.12, <0.05 respectively)

Topographic results of synthetic and allograft rings used in the treatment of keratoconus was similar, and allograft rings may be associated with better outcomes in terms of visual rehabilitation.