Tae Gi Kim

The Long-term Clinical Outcome after Corneal Collagen Cross-linking in Korean Patients with Progressive Keratoconus

Purpose To evaluate the long-term clinical effectiveness and safety of corneal collagen cross-linking (CXL) in progressive keratoconus compared with untreated contralateral eyes. Methods In this retrospective study, nine eyes of nine patients with progressive keratoconus who received CXL (treatment group) and nine untreated contralateral eyes with keratoconus (control group) were included. All patients were followed for at least 5 years and assessed with best-corrected visual acuity, maximum keratometry, mean keratometry, corneal astigmatism, and corneal thickness. Clinical data were collected preoperatively and at 1, 3, 6, 12, 24, 36, 48, and 60 months, postoperatively. Results Mean best-corrected visual acuity improved significantly from 0.58 ± 0.37 logarithm of minimum angle of resolution preoperatively to 0.39 ± 0.29 logarithm of minimum angle of resolution at 5 years after corneal CXL (p = 0.012). There was significant flattening of the maximum keratometry and mean keratometry from preoperative values of 63.39 ± 10.89 and 50.87 ± 6.27 diopter (D) to postoperative values of 60.89 ± 11.29 and 49.54 ± 7.23 D, respectively (p = 0.038, 0.021). Corneal astigmatism decreased significantly from 7.20 ± 1.83 D preoperatively to 5.41 ± 1.79 D postoperatively (p = 0.021). The thinnest corneal thickness decreased from 434.00 ± 54.13 to 365.78 ± 71.58 µm during 1 month after treatment, then increased to 402.67 ± 52.55 µm at 5 years, which showed a statistically significant decrease compared to the baseline (p = 0.020). In the untreated contralateral eyes, mean keratometry increased significantly at 2 years compared with the baseline (p = 0.043). Conclusions CXL seems to be an effective and safe treatment for halting the progression of keratoconus over a long-term follow-up period of up to 5 years in progressive keratoconus.

The Effects of Distance Between the Corneal Apex and the Inner and Outer Corneal Wound Edges on Corneal Astigmatism After Cataract Surgery

PURPOSE To compare the effects of the distance from the inner and outer corneal incision wounds to the corneal apex on the changes in corneal astigmatism after cataract surgery. METHODS Seventy-two eyes with anterior corneal astigmatism less than 2.50 diopters (D) were evaluated. The distance between the incision wound and the corneal apex was measured using the Pentacam (Oculus Optikgeräte, Wetzlar, Germany) Scheimpflug image and the Image J program (National Institutes of Health, Bethesda, MD). Patients were subgrouped into the inner incision distance close (less than 4,816.44 µm) and far (4,816.44 µm or greater) groups based on the median value of inner incision distance and the outer incision distance close (less than 6,131.77 µm) and far (6,131.77 µm or greater) groups based on the median value of outer incision distance. RESULTS In the inner incision distance group, the mean change in anterior, posterior, and total corneal astigmatism at 1 week and anterior astigmatism at 1 month were statistically significantly greater in the inner incision close group than in the inner incision far group. In the outer incision distance group, the mean change in anterior corneal astigmatism at 1 week was statistically significantly greater in the close group than in the far group. Surgically induced astigmatism (SIA) of the posterior cornea showed a statistically significant increase in the inner incision close group compared to the inner incision far group 1 month postoperatively, whereas there were no significant differences in the outer incision distance groups. Inner incision distance significantly correlated with the mean change in anterior and posterior corneal astigmatism and posterior SIA at 1 week postoperatively. CONCLUSIONS Corneal astigmatism was affected more by inner incision distance than outer incision distance, and a larger change in the posterior SIA was noted with decreasing inner incision distance. During cataract surgery, the position of the inner corneal incision should be considered rather than the outer incision. [J Refract Surg. 2017;33(7):460-468.].

Spontaneous corneal perforation in Terrienʼs marginal degeneration in childhood: A case report

Rationale: Terriens marginal corneal degeneration (TMD) is characterized by progressive peripheral corneal thinning. It appears primarily above the age of 40 years and is rare at younger ages. Spontaneous corneal perforation in TMD is a rare, but serious complication that may occur in childhood. Patient concerns: This review presents the case of a 16-year-old girl presented with blurred vision in the right eye on awakening in the morning. Slit-lamp examination revealed superior corneal thinning with a corneal perforation. Diagnoses: The best-corrected visual acuity (BCVA) was 20/50 in the right eye and 20/20 in the left eye. Intraocular pressures were 5 and 18 mm Hg in the right and left eyes, respectively, measured using a noncontact tonometer. Slit-lamp examination revealed superior corneal thinning with superficial pannus. A 1-mm corneal perforation was observed at the 11 o’clock position. The anterior chamber of the right eye was flat and the Seidel test result was positive. The left eye showed no apparent abnormality on slit-lamp examination. Corneal topography showed 4.3 D of against-the-rule astigmatism, and anterior segment optical coherence tomography revealed superior corneal thinning. We diagnosed it as childhood onset TMD. Interventions: Multilayered amniotic membrane transplantation was performed over the perforation site and a bandage contact lens was placed. Outcomes: At 1 week postoperatively, the BCVA of the right eye improved to 20/32, the amniotic membrane graft was well-attached, and the anterior chamber remained deep. At 2 months postoperatively, the BCVA was 20/25 and the anterior chamber depth was maintained. Lessons: Spontaneous corneal perforation due to TMD is rare, but may occur in childhood. The possibility of corneal perforation should be considered even in childhood and good surgical results can be obtained with amniotic membrane transplantation.