Evaluation of axis alignment and refractive results of toric phakic IOL using image-guided system.

AIM: To evaluate accuracy of axis alignment and refractive results of toric phakic intraocular lens (IOL) implantation using a digital imaging system. METHODS: This retrospective study investigated toric implantable collamer lens (ICL) implantation in 30 eyes of 21 patients with myopic astigmatism more than 2.0 D guided with digital imaging system. Data were collected during the first week after phakic IOL implantation. RESULTS: Thirty eyes of 21 patients were included in our study. Patients includes 9 males and 12 females. The mean age of the patients was 26.5±7.1 (range 21-44)y. The mean preoperative manifest astigmatism was 3.2±1.7 (range from 2.25 to 4.75) D. The mean postoperative uncorrected distance visual acuity (UCDVA) were 0.07±0.07 (range from 0.1 to 0.0) logMAR. The mean postoperative residual refractive cylinder was 0.25±0.29 (range 0-0.75) D. Eyes with postoperative residual refractive cylinder of 0.5 D or less represented 80% (24 eyes). The mean postoperative toric IOL misalignment measured by the OPD scan III was 1.9°±1.45° (range from 0 to 5°). CONCLUSION: Image guided system allows accurate alignment of toric ICL. This is associated with good postoperative visual acuity and low residual refractive astigmatism which correlates with the precision of toric phakic IOL alignment.

Visual and refractive outcomes of posterior chamber phakic IOL in stable keratoconus.

We evaluated the visual and refractive outcomes after phakic visian toric implantable collamer lens (ICL) insertion in stable keratoconus (KC). This retrospective study investigated toric ICL implantation in 14 eyes of 8 patients with stable KC. After 6mo, the mean uncorrected distance visual acuity improved significantly from 0.77 to 0.15 logMAR. The mean best corrected distance visual acuity (BCDVA) improved from 0.18±0.1 to 0.15±0.1 logMAR. Fifty percent of eyes maintained their preoperative BCDVA; 42.8% gained one line. There was no statistical difference in high order or coma aberration. The mean refractive manifest spherical equivalent (MSE), mean refractive manifest spherical error, mean manifest astigmatism decreased significantly postoperatively. At 6mo postoperatively, our achieved mean spherical equivalent was approximately 74%. No intraoperative or postoperative complications occurred. Toric ICL implantation was effective, predictable and safe to correct refractive error and improve visual acuity in patients with stable KC.

Comparison of Central Corneal Thickness Measurements by Pentacam and Ultrasound Pachymetry in Normal Myopic Patients.

INTRODUCTION: Precise measurement of corneal thickness is of crucial importance in corneal refractive procedures. The aim of this work is to compare the central corneal thickness measurements using Scheimpflug imaging (Pentacam) and contact US pachymetry in normal myopic patients. METHODS: This retrospective cohort study was conducted on in 144 eyes of 72 normal myopic patients during 6 months. The study location was the Research Institute of Ophthalmology (Giza, Egypt), and Magrabi Eye Hospital (Dubai, United Arab Emirates). Central corneal thickness was measured with the two devices. Data were analyzed by descriptive statistics, independent-samples t-test, paired-samples t-test, Mann-Whitney U test and Pearson-Product Moment Correlation Coefficient. RESULTS: The mean age was 25.3±5.6 years (range 18 to 38 years). The median age for our patients is 24 years. The average measurements of CCT were 526.8±35.3 and 529.1±37.9 for the Pentacam pachymetry and US pachymetry values, respectively. Mean difference between both measurements was 2.3±2.6µm which is statistically insignificant (p=0.08). Bland Altman Plot shows border line agreement of the two methods US pachymetry and Pentacam in detection of central corneal thickness. CONCLUSION: The results of this study showed no significant differences in CCT readings between the measurements obtained by Pentacam and US pachymetry in normal myopic patients.

Corneal healing after uncomplicated LASIK and its relationship to refractive changes: a six-month prospective confocal study.

PURPOSE: To investigate corneal healing and the factor(s) possibly responsible for refractive changes after laser in situ keratomileusis (LASIK). METHODS: Twenty eyes of 10 patients who underwent LASIK for myopia were examined clinically and by real-time confocal microscopy for 6 months. Epithelial and posterior stromal thicknesses and the thickness of the keratocyte activation zone were measured, and refractive changes were compared with these values. Keratocyte morphology, flap thickness, and subbasal nerve fiber bundle morphology after LASIK were also investigated. RESULTS: No significant change was detected over time in epithelial thickness after LASIK treatment; however, the posterior stromal thickness was found to be significantly higher 1 month after surgery. A slight but statistically significant negative correlation was detected between the thickness of the keratocyte activation zone and the spheroequivalent refraction after LASIK. The subbasal nerve fiber bundle's morphology returned to its preoperative appearance 6 months after LASIK, but in the flap stroma the nerve fiber bundle morphology remained abnormal at 6 months after LASIK surgery. CONCLUSIONS: A weak but significant negative correlation between the thickness of the keratocyte activation zone and spheroequivalent refraction was found after LASIK. The different refractive properties of activated keratocytes may be responsible for the myopic shift after LASIK. Further studies are needed to clarify this hypothesis.