Epithelial thickness map-adjusted transepithelial photorefractive keratectomy for treatment of myopic astigmatism: 12-month results.

PURPOSE: To evaluate the refractive results of Transepithelial Photorefractive Keratectomy (t-PRK) with the Technolas Teneo2 Excimer laser platform. METHODS: In this retrospective comparative interventional case series, a total of 199 patients with myopia ranging from - 1 to - 7 diopters were enrolled and separated into three groups based on their target refraction of zero (group 1), - 0.25 (group 2), and - 0.5 diopters (group 3), respectively. The main outcome measure was post-operative cycloplegic refraction. Trans-PRK was performed using the Technolas Teneo2 Excimer laser. To prevent any remaining epithelium during stromal ablation, we adopted the thickest epithelial point in the 7 mm central map as the reference for Phototherapeutic keratectomy (PTK) depth. Patients were examined three and twelve months after the procedure, and the results were analyzed. RESULTS: At the 12-month follow-up, uncorrected distance visual acuity was 20/20 in all patients. However, there was a significant difference in cycloplegic spherical equivalent refraction between the three groups. The 12-month post-operative spherical equivalent refraction was 0.90 ± 0.33 D, 0.79 ± 0.26 D, and 0.60 ± 0.19 D in groups 1, 2, and 3, respectively (P < 0.001; Kruskal-Wallis test). The rates of spherical equivalent refraction of more than 0.75 D were 58.3%, 39.1%, and 9.1% in the 0 D, - 0.25 D, and -0.50 D groups, respectively (P < 0.001; Chi-squared test). CONCLUSIONS: The t-PRK with Technolas Teneo2 Excimer laser and epithelial thickness map adjustment of PTK induce a significant amount of residual hyperopia (> 0.75 D) in a large proportion of eyes with a target refraction of 0 or - 0.25, which is significantly reduced by using a target refraction of - 0.5.

Femtosecond laser-assisted decagonal deep anterior lamellar keratoplasty.

OBJECTIVE: To assess the use of a new polygonal trephination pattern for deep anterior lamellar keratoplasty (DALK) assisted by femtosecond laser. DESIGN: Prospective, nonrandomized clinical study. METHODS: Twenty-four eyes underwent decagonal DALK. All except 1 had advanced keratoconus. A laser was used to create decagonal cuts on both donor and recipient corneas. All patients were assessed for uncorrected visual acuity, best spectacle-corrected visual acuity (BCVA), and keratometry by Pentacam pre- and postoperatively. RESULTS: All eyes were treated successfully without intraoperative complications. All patients were followed for 18 months. Mean ± SD of postoperative BCVA was 0.26 ± 0.16 (logarithm of minimal angle of resolution), and there was a significant improvement in BCVA after 6 months. At 18 months, mean ± SD postoperative average K was 44.48 ± 0.87 D, which was significantly lower than preoperative average K (58.42 ± 12.1). Postoperative astigmatism at 18 months (mean ± SD: 1.82 ± 0.67) was significantly lower than that at 6 months (mean ± SD: 3.27 ± 0.81) (p = 0.001). CONCLUSIONS: Use of the decagonal trephination profile was effective to perform DALK. This study showed promising visual and refractive results. Longer follow-up, larger pool of patients, and comparative studies are necessary to determine advantages and optimal surgical settings of this technique.

Treatment of moderate to severe keratoconus with 6-mm Intacs SK.

AIM: To evaluate the effect of Intacs SK corneal ring segment implant for treatment of patients with moderate to severe keratoconus, who have clear central cornea and cannot tolerate contact lens. METHODS: In this prospective, non-comparative, interventional case series study performed in Dena Hospital, Shiraz, Iran, thirty-seven eyes of thirty-six patients with moderate to severe keratoconus, clear central cornea, and contact lens intolerance were enrolled and underwent Intacs SK corneal ring segment implantation. Preoperatively, uncorrected distance visual acuity (UCDVA), best-corrected distance visual acuity (BCDVA), central corneal thickness(CCT) and average keratometry (Av-K) were measured and compared with post-operative results at one week, one month, three months, and six months. RESULTS: Mean preoperative UCDVA and BCDVA were (1.32±0.31)logMAR and (1.07±0.27)logMAR, respectively. Av-K was (52.13±0.39)D, and the CCT was (432±39.5)µm. Post-operative examinations showed a clinically significant improvement in both UCDVA and BCDVA (P<0.001). There was also a significant effect based on the time of assessment on both UCDVA and BCDVA and both parameters had a continuous improvement during the follow-up period. Three months after operation there was a statistical significant reduction of Av-K (P=0.0001), but there were no significant changes in CCT (P=0.149). CONCLUSION: Intacs SK corneal ring segment implants seem to be a safe and effective treatment option for patients who have keratoconus, clear central cornea, and contact lens intolerance.

Shifting bubble sign, a useful tip in manual dissection of deep anterior lamellar keratoplasty / 国际眼科杂志(Guoji Yanke Zazhi)

Here we describe shifting bubble sign in manual dissection of deep anterior lamellar keratoplasty (DALK). This sign can be noticed in more than 99% of patients. It is very useful in phakic keratoconic eyes, the leading indication for DALK. We believe that our small modification can help surgeons early in learning curve to avoid inadvertent anterior chamber penetration during the final stages of DALK.

Fixed dilated pupil (urrets-zavalia syndrome) after deep anterior lamellar keratoplasty.

PURPOSE: To report 4 cases that developed fixed dilated pupil after deep anterior lamellar keratoplasty (DALK) for treating keratoconus and granular corneal dystrophy. METHODS: Four patients underwent DALK (either Melles's manual dissection or Anwar's big-bubble technique) with diagnosis of keratoconus (2 cases) and granular corneal dystrophy (2 cases). In Melles's technique, the anterior chamber was fully filled with air at the beginning of procedure. When corneal dissection was complete, air was replaced with balanced salt solution. In Anwar's technique, a large bubble was formed between Descemet's membrane and the deepest stroma. Viscoelastic was not used within the anterior chamber in either technique. For microperforation, air was left in the anterior chamber for a couple of days. Two patients developed severe fibrinous anterior uveitis that was controlled with intense topical and systemic steroid. Other two patients developed high intraocular pressure that was controlled with antiglaucoma medications. RESULTS: After 1-2 weeks, all 4 DALK patients developed fixed dilated pupil and posterior synechiae; 2 patients developed a faint anterior subcapsular opacity. Of 286 patients who underwent DALK, 6 patients had microperforation (2%) and 4 patients developed fixed dilated pupil (1.4%). Best-corrected visual acuity (BCVA) decreased in all patients; most of them complained about visual symptoms like glare and halo at night. CONCLUSIONS: Fixed dilated pupil (Urrets-Zavalia syndrome) is an uncommon but rather serious complication of corneal transplantation. Iris ischemia is the most common proposing mechanism. Decreased BCVA and visual symptoms at night (glare and halo) are late sequelae.A fixed dilated pupil with iris atrophy (Urrets-Zavalia syndrome) is an uncommon postoperative complication that was originally described after penetrating keratoplasty for keratoconus. In these cases, the iris is fixed and dilated and adheres to anterior lens capsule. Prepupillary iris atrophy is usually seen and may be accompanied by a severe fibrinous reaction and anterior subcapsular lens opacity.

Comparison of anterior and posterior elevation map measurements between 2 Scheimpflug imaging systems.

PURPOSE: To compare the anterior and posterior elevation measurements above the best-fit sphere (BFS) between the Galilei (dual-Scheimpflug) and Pentacam (single-Scheimpflug) systems in candidates for refractive surgery. SETTING: Poostchi Ophthalmology Research Center, Shiraz, Iran. METHODS: In this prospective study, both eyes of consecutive patients were examined with the 2 imaging systems. The anterior and posterior BFS and the central and maximum elevation measurements in each of 4 quadrants were compared between the dual-Scheimpflug system and the single-Scheimpflug system. Bland-Altman plots were used to evaluate the agreement in the measurements between the imaging systems. RESULTS: The study comprised 31 patients (62 eyes). The mean radius of the anterior BFS measurement was 7.72 mm +/- 0.21 (SD) with the dual-Scheimpflug system and 7.83 +/- 0.21 mm with the single-Scheimpflug system. The mean radius of the posterior BFS was 6.37 +/- 0.18 mm and 6.47 +/- 0.19 mm, respectively. On the anterior and posterior elevation maps, the single-Scheimpflug system led to statistically significantly higher measurements than the dual-Scheimpflug system in the central, inferior, and temporal elevations (P<.001). Bland-Altman plots showed more agreement between the systems in anterior elevation measurements than in posterior elevation measurements. CONCLUSION: In refractive surgery candidates with healthy eyes, the elevation map measurements with the single-Scheimpflug system were significantly different from those with the dual-Scheimpflug system in most aspects and therefore may lead to misinterpretation of clinical data that could alter clinical decisions if the 2 imaging systems are considered interchangeable.