Authors refer about the effect of adjusting (adjustment of the suture tension) of the running corneal suture on the final cylindrical refraction in patients who underwentpenetratingkeratoplastyduetokeratoconus.Inourarticleweevaluate two groups of patients. The group I consists 76 patients (76 eyes) who regularly visited our department of ophthalmology. There were 52.6 % of females and 47.4 % ofmales. The average age at the time of surgery was 33.5 ± 5.2 years (range, 18 – 52 years). In this group of patients, the adjusting was performed during the surgery. In the group II 35 patients (40 eyes) underwent the adjusting procedure of the running corneal suture in the early postoperative period. There were 19 (54.0 %) women and 16 (46.0 %) men. The average age of the whole group at the time of surgery was 34.6 ± 3.8 years (range, 18 – 50 years). The indication to carry out the adjusting was topographically verified astigmatism of more then 3.5 cylindrical diopters (D cyl). The purpose of this study was to find the ultimate surgery technique to get not only the clearness and good healing of the corneal graft, but first of all to prevent extensiveametropia alreadyduringthesurgery.In theearly stageafter thesurgery we are trying to reduce emerged refractive error and to get faster recovery of good visual acuity of the operated eye. In the sense of the least final postoperative astigmatism, the best results we have reached in cases where the donor corneal graft was 0.25 mm larger in diameter and the suture was adjusted during the surgery using light circles according to Serdarevic. In this group of patients the average final cylindrical refractive error after the surgery was 2.00 ± 0.81 D cyl. When adjusting the corneal suture in postoperative period, the mean final refractive error decreased of about 3.09 ± 1.62 D cyl.penetrating keratoplasty, adjusting of the corneal suture, cylindrical refraction.

        Key words: penetrating keratoplasty, adjusting of the corneal suture, cylindrical refraction.