Yasin Çınar

Long-Term Results of Deep Anterior Lamellar Keratoplasty for the Treatment of Keratoconus

PURPOSE To evaluate the long-term endothelial cell density (ECD) changes and visual and refractive outcomes after deep anterior lamellar keratoplasty (DALK) using the big-bubble technique in eyes with keratoconus. DESIGN Retrospective interventional case series study. METHODS setting: Single hospital. patients: Two hundred forty-one eyes of 214 patients who underwent DALK for moderate to advanced keratoconus. main outcome measures: Intraoperative and postoperative complications, postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), spherical equivalent refraction, topographic astigmatism, and ECD. RESULTS Two hundred thirty-four procedures (97%) were completed as DALK. Big bubble was successfully achieved in 193 eyes (82.4%). In 7 eyes (3%), the procedure was converted to penetrating keratoplasty because of Descemet membrane macroperforations. Microperforations occurred in 18 eyes (7.5%). The mean follow-up time was 50.5 ± 22.2 months (range 24 to 96 months). UCVA was lower than 20/100 in all eyes preoperatively and better than 20/100 in 191 eyes (81.6%) postoperatively. BSCVA was 20/40 or better in 187 eyes (79.9%) and 20/20 or better in 38 eyes (16.2%). The mean (± SD) preoperative ECD that was possible in 166 eyes was 2797 ± 561 cells/mm(2). Mean (± SD) endothelial cell loss was 8.1% ± 4.6% at 1 year, 10.5% ± 5.7% at 2 years, 15.1% ± 14.8% at 6 years, and 22.5% ± 15.9% at 8 years. Stromal graft rejection episodes occurred in 4 eyes, which resolved with appropriate therapy. CONCLUSIONS Deep anterior lamellar keratoplasty that uses the big-bubble technique is effective in patients with keratoconus. Long-term endothelial cell loss was moderate and lower than penetrating keratoplasty grafts.

Comparison of accelerated and conventional corneal collagen cross-linking for progressive keratoconus

Abstract Purpose: To compare outcomes of accelerated and conventional corneal cross-linking (CXL) for progressive keratoconus (KC). Materials and methods: Patients were divided into two groups as the accelerated CXL group and the conventional CXL group. The uncorrected distant visual acuity (UDVA), corrected distant visual acuity (CDVA), refraction and keratometric values were measured preoperatively and postoperatively. The data of the two groups were compared statistically. Results: The mean UDVA and CDVA were better at the six month postoperative when compared with preoperative values in two groups. While change in UDVA and CDVA was statistically significant in the accelerated CXL group (p = 0.035 and p = 0.047, respectively), it did not reach statistical significance in the conventional CXL group (p = 0.184 and p = 0.113, respectively). The decrease in the mean corneal power (Km) and maximum keratometric value (Kmax) were statistically significant in both groups (p = 0.012 and 0.046, respectively in the accelerated CXL group, p = 0.012 and 0.041, respectively, in the conventional CXL group). There was no statistically significant difference in visual and refractive results between the two groups (p > 0.05). Conclusions: Refractive and visual results of the accelerated CXL method and the conventional CXL method for the treatment of KC in short time period were similar. The accelerated CXL method faster and provide high throughput of the patients.

Comparison of mechanical and femtosecond laser tunnel creation for intrastromal corneal ring segment implantation in keratoconus: Prospective randomized clinical trial

PURPOSE: To compare the outcomes of mechanical and femtosecond laser–assisted tunnel creation for intrastromal corneal ring segment (ICRS) implantation in eyes with keratoconus. SETTING: Kartal Training and Research Hospital, Istanbul, Turkey. METHODS: In this prospective study, consecutive eyes with keratoconus were randomly assigned to have ICRS tunnel creation with a mechanical device or a femtosecond laser. Keraring ICRS with a 5.0 mm diameter and 160‐degree arc length were implanted in all cases. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, and keratometry (K) readings were measured preoperatively and 1 year postoperatively, and the data in the mechanical group and the femtosecond group were compared statistically. RESULTS: One year postoperatively, there was significant improvement in UDVA, CDVA, K readings, spherical equivalent (SE), and manifest sphere and cylinder in both groups (P<.05). The UDVA improved by 2.4 lines in the mechanical group and 2.0 lines in the femtosecond group and the CDVA by 3.3 lines and 2.7 lines, respectively; the mean reduction in maximum keratometry was 4.50 diopters (D) and 4.70 D, respectively, and the mean reduction in SE, 3.18 D and 3.09 D, respectively. There were no statistically significant differences between the 2 groups in visual or refractive results (P>.05). Anterior corneal perforation, superficial segment placement, and segment extrusion occurred in 1 eye each in the mechanical group. Segment migration occurred in 1 eye in the femtosecond group. CONCLUSION: Despite intraoperative complications in the mechanical group, the visual and refractive outcomes were similar to those in the femtosecond group. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Accelerated corneal collagen cross-linking for progressive keratoconus

Abstract Purpose: To evaluate the efficacy of accelerated corneal cross-linking (CXL) procedure for progressive keratoconus. Materials and methods: Twenty-three eyes of 23 patients undergone accelerated CXL procedure were evaluated preoperatively and postoperatively at 1st, 3rd and 6th month for uncorrected distant visual acuity (UDVA), best corrected distant visual acuity (CDVA), spherical error, cylindrical error, spherical equivalent (SE), keratometric values and thinnest corneal thickness (TCT) values with corneal topography by Scheimpflug camera and endothelial cell density (ECD). Results: The mean UDVA was improved from 0.97 ± 0.41 logarithm of minimal angle of resolution (logMAR) to 0.76 ± 0.45 logMAR at the 6th month after CXL (p = 0.332). The mean CDVA was improved from 0.49 ± 0.30 logMAR to 0.34 ± 0.22 logMAR at the 6th month after CXL (p = 0.026). The mean sphere was decreased from −4.47 ± 4.1 diopter (D) to −3.79 ± 3.86 D and the mean cylinder was decreased from −5.60 ± 2.2 D to −4.55 ± 1.98 D and the mean SE was decreased from −7.22 ± 4.48 D to −6.36 ± 4.34 D at the 6th month after CXL (p = 0.128, p = 0.002 and p = 0.045, respectively). Flat keratometry, steep keratometry, mean keratometry and maximum keratometry were significantly reduced at the 6th month after CXL (p = 0.025, p < 0.001, p = 0.004 and p = 0.03, respectively). TCT and ECD were not changed significantly the 6th month after CXL (p = 0.135 and p = 0.082, respectively). Conclusion: Accelerated CXL procedure was effective to stabilize progression of keratoconus with significant reduction in topographic keratometric values and significant increase in CDVA in 6 months.

Intrastromal Corneal Ring Segment Implantation for the Treatment of Keratoconus

Purpose: To evaluate the safety and efficacy of intrastromal corneal ring segment implantation using both mechanical and femtosecond-assisted tunnel creation for the treatment of patients with keratoconus. Methods: A retrospective noncomparative interventional study including 96 eyes of 75 patients with keratoconus. All patients had contact lens intolerance and clear central corneas. Corneal tunnels were made using a femtosecond laser in 26 eyes (femtosecond group) and mechanically in 70 eyes (mechanical group). The Keraring (Mediphacos, Belo Horizonte, Brazil) was implanted in each eye, and a complete ophthalmic examination was performed, including visual acuity, refraction, and keratometric readings. Results: The mean preoperative uncorrected visual acuity for all eyes was 1.40 ± 0.39 logarithm of the minimal angle of resolution (logMAR) (mean ± SD) and improved to 0.60 ± 0.34 logMAR at the sixth month (n = 96, P < 0.001) and 0.50 ± 0.32 (n = 54, P < 0.001) at the 18th month. The mean preoperative best spectacle-corrected visual acuity (BSCVA) for all eyes (n = 96) was 0.68 ± 0.36 logMAR. The mean BSCVA was 0.29 ± 0.21 (n = 96, P < 0.001) at the sixth month and improved to 0.26 ± 0.20 (n = 54, P < 0.001) at the 18th month. There was a significant reduction in spherical equivalent refractive error from −5.88 ± 3.65 diopters (D) (n = 96) to −2.26 ± 1.98 D (n = 54, P < 0.001) at the 18th month. The mean preoperative maximum keratometry (Kmax) was 53.58 ± 5.90 D and decreased to 49.02 ± 4.70 (n = 96, P < 0.001) at 6 months and 48.57 ± 4.36 D (n = 54, P < 0.001) at the 18th month. Sixth month results of the mechanical versus femtosecond groups were as follows: improvement in uncorrected visual acuity (2.08 vs. 1.50 lines), improvement in BSCVA (2.93 vs. 2.19), reduction in spherical equivalent (3.78 vs. 3.75 D), and reduction in maximum keratometry (4.66 vs. 4.62 D). There was no statistically significant difference between both groups for any parameter. Conclusions: Keraring implantation is effective for the treatment of keratoconus, providing safety and good visual outcomes after both mechanical and femtosecond-assisted tunnel creation.

Transient corneal endothelial changes following accelerated collagen cross-linking for the treatment of progressive keratoconus

Abstract Purpose: To evaluate the corneal endothelial changes following accelerated collagen cross-linking (CXL) for the treatment of progressive keratoconus. Methods: Thirty-six consecutive progressive keratoconus patients who received accelerated CXL treatment were enrolled in the study. Following de-epithelization, isoosmolar 0.1% riboflavin solution without dextran was instilled every 3 min throughout the 30 min of soaking time before the 5 min of 18 mW/cm2 UVA irradiation and every 2 min during the UVA irradiation. Corneal specular microscopy was performed on both treated and fellow eyes of each patient preoperatively, in the first week, and in the first, third and sixth month postoperatively. Results: There were significant differences in endothelial cell density (ECD), percentages of hexagonality (6A) and coefficient of variation of endothelial cell area (CV) in the first week and first month postoperatively in the treated eyes when compared to their preoperative values and also to the first week and first month ECD, 6A and CV values of the non-operative eyes. ECD returned to the preoperative values at sixth month whereas 6A and CV returned to the preoperative values at third month. Conclusion: Our results suggested that there may be transient changes in human corneal endothelium following accelerated UVA/riboflavin CXL. Resolution of these changes during the follow-up may indicate a safe recovery. However, the treatment guidelines for accelerated CXL including irradiance level and soaking time should be clearly established to minimize the toxic effects of the treatment.

Effects of vernal and allergic conjunctivitis on severity of keratoconus

AIM To demonstrate the effects of two different types of allergic conjunctivitis on severity of keratoconus (KC). METHODS We retrospectively reviewed the medical records of 171 KC patients referred between June 2010 and June 2011. The KC patients were divided into 3 groups as KC (group A), KC with vernal keratoconjunctivitis (VKC) (group B) and KC with allergic conjunctivitis (AC) (group C). Main outcome measures were demographic and ocular clinical features including age at presentation, gender, spherical equivalent (SE), best spectacle corrected visual acuity (BCVA), mean keratometric measurement (Km), central corneal thickness (CCT), and intraocular pressure (IOP). Groups were compared in term of study variables. RESULTS The median age at presentation was significantly lower in group B (P<0.001). According to the median SE (P=0.003), BCVA (P=0.022), Km (P<0.001), CCT (P=0.015) and Amsler-Krumeich classification (P<0.001), KC was more severe in group B. There was no significant difference in terms of IOP and corrected IOP among the groups (P=0.44), however there were 4 patients who had increased corrected IOP developed after topical corticosteroid use in group B. The differences among the groups persisted even after controlling for age and gender. CONCLUSION Our findings demonstrated a more severe KC in VKC patients despite their younger age which suggests evaluation of VKC patients as a separate group in keratoconus disease.

Intravitreal bevacizumab monotherapy for retinopathy of prematurity.

The aim of this study was to evaluate the treatment outcomes of intravitreal bevacizumab (IVB) injections, used as a monotherapy in type 1 retinopathy of prematurity (ROP).

The effects of Nd:YAG laser posterior capsulotomy on macular thickness, intraocular pressure, and visual acuity.

BACKGROUND AND OBJECTIVE To evaluate how different energy levels of Nd:YAG laser posterior capsulotomy affect best-corrected visual acuity (BCVA), intraocular pressure (IOP), and macular thickness of patients with posterior capsule opacification. PATIENTS AND METHODS Thirty eyes of 30 patients with posterior capsule opacification following phacoemulsification were enrolled in the study. Patients were classified according to total energy used during Nd:YAG laser capsulotomy (≤ 80 mJ = group I, > 80 mJ = group II). RESULTS Mean total energy levels were 58 ± 18 mJ (range: 14 to 80 mJ) in group I and 117 ± 36 mJ (range: 84 to 200 mJ) in group II. BCVA at 1 week preoperatively and 1 and 3 months postoperatively was significantly better compared to preoperative BCVA in both groups (P < .001). In group I, IOP increased 1 week postoperatively (P = .007) and declined to preoperative levels at 1 month. In group II, IOP increased 1 week postoperatively (P = .001) and did not return to preoperative levels during 3 months of follow-up (P = .04). Both groups had increased macular thickness compared to preoperative levels, but group II measurements were significantly higher 1 week and 1 month postoperatively compared to group I (P = .004 and .03, respectively). CONCLUSION Increased IOP and macular thickness are inevitable after Nd:YAG laser capsulotomy, but the severity and duration are less when a total energy level less than 80 mJ is used.

The Mean Platelet Volume in Patients with Retinal Vein Occlusion

Background. The aim of this study was to investigate the mean platelet volume (MPV) of patients with retinal vein occlusion (RVO). Methods. Hundred and ninty-three patients with the diagnosis of RVO and 83 healthy control subjects were included in this retrospective study. Retinal vein occlusion was diagnosed based on clinical examination. All patients and control subjects underwent complete ocular examination. MPV, hematocrit, hemoglobin, and platelet count of the participants were recorded. The data of patients with RVO was compared with the control subjects. Results. Patients with RVO had significantly higher MPV values (8.19 ± 1.22 fL) compared with the control subjects (7.68 ± 1.11 fL) (P = 0.004). No significant difference was found in platelet counts between RVO group and the control group (275.77 ± 70.87 109/L and 261.96 ± 59.40 109/L, resp., P = 0.161), Mean platelet volume was an independent predictor of RVO (odds ratio (OR) = 1.43; 95% confidence interval (CI) = 1.09–1.89; P = 0.011). Conclusion. Our results demonstrated that the MPV values were significantly higher in patients with RVO, suggesting that larger platelets may contribute to the pathogenesis of the RVOs.