Unwanted Astigmatism and High-order Aberrations One Year after Excimer and Femtosecond Corneal Surgery.

SIGNIFICANCE: Small incision lenticule extraction (SMILE) is advanced as the most minimally invasive and least traumatic corneal procedure for correcting refractive errors using a single laser. Although SMILE obtains similar results to femtosecond laser in situ keratomileusis (LASIK) with spherical myopia, it has deficiencies in astigmatism correction. PURPOSE: The purpose of this study was to compare refractive outcomes and high-order aberrations (HOAs) between SMILE and femtosecond LASIK corneal procedures at 1 year post-operative. METHODS: Ninety-two patients (181 eyes) with myopia/myopic astigmatism underwent either SMILE (group 1) or femtosecond LASIK (group 2). The refractive target was to achieve emmetropia in all cases. Data were analyzed to determine significance of change in refraction and HOAs. Furthermore, astigmatism was subjected to vector analysis using the Thibos (calculation of change, Δ, in J0 and J45 values) and Alpins (calculation of difference, ΔC, between target-induced astigmatism [TIA] and surgically induced astigmatism) methods. RESULTS: Forty-five patients (89 eyes) from group 1 and 47 patients (92 eyes) from group 2 completed the study. The main significant (P ≤ .001) findings were as follows: (a) residual astigmatism was greater in group 1; (b) group 1, ΔJ0 = 1.015J0 + 0.040 (R = 0.861), ΔJ45 = 1.082J45 + 0.019 (R = 0.792), ΔC = 0.401TIA + 0.323 (R = 0.489), and mean spherical aberration increased from -0.003 (SD, ±0.059; 95% confidence interval [CI], -0.015 to 0.009) to 0.028 µm (SD, ±0.041; 95% CI, -0.037 to -0.020); and (c) group 2, ΔJ0 = 0.952J0 - 0.005 (R = 0.921), ΔJ45 = 0.962J45 - 0.002 (R = 0.923), ΔC = 0.187TIA + 0.101 (R = 0.272), mean coma reduced from 0.114 (SD, ±0.087; 95% CI, 0.096 to 0.132) to 0.077 µm (SD, ±0.059; 95% CI, 0.065 to 0.089), and trefoil from 0.089 (SD, ±0.049; 95% CI, 0.079 to 0.0990) to 0.056 µm (SD, ±0.047; 95% CI, 0.046 to 0.066). CONCLUSIONS: In comparison with SMILE, femtosecond LASIK offered better precision in the overall control of astigmatism and HOAs.

Incidence and Clinical Characteristics of Post LASIK Ectasia: A Review of over 30,000 LASIK Cases.

PURPOSE: To report the incidence of postoperative ectasia after laser in situ keratomileusis (LASIK). METHODS: A retrospective case review of 30,167 eyes (16,732 patients) was conducted following LASIK between August 2007 and August 2015. The follow-up was between 2 and 8 years. Tomography was performed after 2 years postop. After identifying cases of ectasia, the charts of these patients were examined to identify any common factors that may have predisposed them to develop ectasia. RESULTS: Ten eyes of seven patients developed post-LASIK ectasia. Eight eyes had been treated for myopia and myopic astigmatism, two eyes for mixed astigmatism. There were no cases of ectasia after LASIK for hyperopia. All 10 cases of ectasia had a flap that was created using the Moria M2 mechanical microkeratome (average flap thickness 118.15 ± 12.88 µm) and refractive error corrected using the Wavelight Allegretto excimer laser. Retrospectively, most prevalent risk factors were thin cornea (≤ 500 µm, 50% of cases), anterior topographic map irregularities (e.g., asymmetric bow tie, 40% of cases), Ectasia Risk Score > 3 (40% of cases), percent tissue thickness alteration ≥ 40% (20% of cases) and low residual stromal bed (≤ 300 µm, 30% of cases). One eye had no identifiable risk factors. In the retrospective chart review 14.97% (4,506) of all the eyes had similar risk factors to the cases that went on to develop ectasia. CONCLUSION: The incidence of ectasia was 0.033% over 8 years. The incidence could be higher as some cases may destabilize beyond this period and some patients were lost to follow-up asymptomatic of any clinical signs. Other intrinsic factors may trigger the development of post LASIK ectasia. The current widely accepted risk factors are not sufficiently rigorous for screening out potential ectasia from developing after LASIK. There is a need to augment accuracy with higher sensitivity and specificity.

Transplantation of amniotic membrane in corneal ulcers and persistant epithelial defects.

Amniotic membrane transplantation (AMT) leads to reduction of inflammatory symptoms and causes faster epithelisation in corneal ulcers and persistant epithelial defect. 21 patients with corneal ulcer (n = 18) or non-healing epithelial defect (n = 3) unresponsive to conventional treatment were included in the study. All patients were treated by AMT. Corneal epithelial cells in patients suffering from corneal ulcer secreted 3.51 +/- 1.79 of IL-1alpha, 64.27 +/- 31.53 pg/mL of TNFalpha and 209.07 +/- 201.82 pg/mL of VEGF. Levels of all 3 investigated cytokines were significantly higher as compared to controls (p < 0.005). Amniotic membranes that were used contained 775.69 +/- 613.98 pg/mL of IL-1alpha, 0.036 +/- 0.033 pg/mL of sTNF and 175.01 +/- 166.63 pg/mL of VEGF-R. Supporting effect of the AMT could be explained by the fact that AM secretes its natural antinflammatory antagonists IL-1ra, sTNF and VEGF-R.

The expression of interleukin-1 alpha, TNF and VEGF in corneal cells of patients with bullous keratopathy.

Bullous keratopathy (BK) is a chronic corneal edema with or without subepithelial bullae as a result of a loss of the endothelial cells. 15 patients with BK after cataract surgery with intraocular lens implantation, due to Fuchs dystrophy (n = 3) or corneal endothelial trauma (n = 12) were included in the study. All patients were treated by amniotic membrane transplantation (AMT). Corneal epithelial cells in patients suffering from BK secreted 3.91 +/- 3.09 pg/mL of IL-1 alpha, 4446 +/- 16.8 pg/mL of TNF and 81.43 +/- 37.81 pg/mL of VEGF-I. Levels of all 3 investigated cytokines were significantly higher as compared to controls (p < 0.005). Amniotic membranes that were used to treat investigated patients contained 638.98 +/- 613.98 pg/mL of IL-1ra, 0.026 +/- 0.009 pg/mL of sTNF and 81.39 +/- 21.01 pg/mL of VEGF-R. Beneficial clinical effect of the AMT in treating BK could be explained by its natural production of pro-inflammatory cytokine antagonists such as IL-ra, sTNF antagonist and VEGF-R.

Vascular endothelial growth factor in aqueous humor of patients with perforative eye injuries.

Considering that VEGF is the key factor for angiogenesis stimulation, we wanted to establish if VEGF level is increased in aqueous humor of patients with open globe eye injury. The study included 20 patients with open globe injury. During the surgery, aqueous humor samples were taken out and VEGF levels were measured by ELISA. VEGF levels were significantly higher in the aqueous humor of patients with open globe eye injury and uveitis, in patients with wound bigger than 2 mm and in patients where from injury to surgery passed more than 4 hours. VEGF levels were also higher, but not significantly, in patients with intrabulbar foreign body. Considering that VEGF levels were significantly higher in patients with open globe eye injury with uveitis, wound larger than 2 mm and in patients where from injury to surgery passed more than 4 hours, anti VEGF therapy might have application in these conditions.

Expression of vascular endothelial growth factor in proliferative diabetic retinopathy.

The study included 20 patients with diabetes mellitus type I (DM I) and 16 with type II (DM II) suffering from prolipherative diabetic retinopathy (PDR) for which they underwent vitrectomy. The quantity of VEGF and its receptors in the vitreous of investigated patients were measured by immunoassay and results compared between patients with DM I and II. The mean levels in the vitreous were significantly higher in diabetics with PDR and diabetes mellitus I (432.2 pg/mL, 1460.4 pg/mL and 1054.6 pg/mL) than in diabetics with PDR and diabetes mellitus II (147.5 pg/mL, 641.4 pg/mL and 448.5 pg/mL) and in control group (63.26 pg/mL). Considering that VEGF VEGFR1 and VEGFR2 levels were significantly higher in diabetics with PDR than in controls and that the patients with DM I had higher levels than with DM II, anti-VEGF therapy might be beneficial for diabetics with PDR, especially those with DM I.

Complications after primary and secondary transsclerally sutured posterior chamber intraocular lens implantation.

This retrospective study analyses and compares early complications during the first month after primary and secondary posterior chamber implantation of transsclerally sutured IOL. The analysis covered medical records of 65 patients who underwent posterior chamber implantation of transsclerally sutured IOL at the Eye Clinic in Rijeka between 1998 and 2003. In 30 patients (group 1) lenses were implanted in one eye during complicated cataract surgery (primary implantation), whereas 35 patients (group 2) had lenses implanted afterwards (secondary implantation). There were 77 early complications, equally represented in both groups, i.e. 40 in (51.9%) the first and 37 (48.1%) in the second group. The most frequent complications were: vitreous hemorrhages 24.7% (14.3% and 10.4%), cystoid macular edema 19.5% (9.1% and 10.4%), keratopathy 14.3% (6.5% and 7.8%), pupil distortion 11.7% (9.1% and 2.6%), IOL decentration and tilt 10.4% (6.5% and 3.9%), high intraocular pressure 9.1% (2.6% and 6.5%), inflammation 6.5% (2.5% and 3.9%). Retinal and choroidal detachment had low incidence: 2.6% (1.3% and 1.3%) and 1.3% (0% and 1.3%) respectively. As concerns early complications, there were no statistically significant differences between the two groups, except for pupil distortion, which was more frequent in primary IOL implantation (p = 0.045). After primary implantation of IOL, the average visual acuity was 0.38 +/- 0.27, whereas after secondary implantation visual acuity was 0.52 +/- 0.21. The difference was not statistically significant.