Corneal wound healing after laser vision correction.

Any trauma can trigger a cascade of responses in tissues, with the purpose of safeguarding the integrity of the organ affected by the trauma and of preventing possible damage to nearby organs. Subsequently, the body tries to restore the function of the organ affected. The introduction of the excimer laser for keratorefractive surgery has changed the treatment landscape for correcting refractive errors, such as myopia, hyperopia, and astigmatism. In recent years, with the increased understanding of the basic science of refractive errors, higher-order aberrations, biomechanics, and the biology of corneal wound healing, a reduction in the surgical complications of keratorefractive surgery has been achieved. The understanding of the cascade of events involved in the corneal wound healing process and the examination of how corneal wound healing influences corneal biomechanics and optics are crucial to improving the efficacy and safety of laser vision correction.

Under-air staining of the anterior capsule using Trypan blue with a 30 G needle.

The original technique of staining the anterior capsule of the lens with Trypan blue involves the injection of an air bubble in the anterior chamber. A drawback of this technique is the possible instability of the anterior chamber caused by the sudden exit of air when the dye is injected with the cannula through the side-port incision. Other staining techniques that use viscoelastic substances to increase the stability of the anterior chamber and to dose the injected dye have been described. The authors present an under-air staining technique of the anterior capsule using one drop of Trypan blue injected with a 30 G needle through the peripheral cornea. This procedure prevents the air bubble from escaping the anterior chamber and allows fast and selective staining of the capsule.

Comparison of macular thickness measurements between time-domain and spectral-domain optical coherence tomographies in eyes with and without macular abnormalities.

PURPOSE: To compare Stratus time-domain optical coherence tomography (OCT) with Cirrus spectral-domain HD-OCT for measuring macular thickness in eyes with and without macular abnormalities. METHODS: Seventy-five eyes of 48 patients were included in the study. Forty-one eyes of 29 patients had a normal macular thickness, and 34 eyes of 26 patients had an abnormal macular thickness. Macular scans were performed by 2 examiners (E1 and E2) with both OCTs. The agreement between the two OCT systems and interrater repeatability of each OCT system were determined using the Bland-Altman method. RESULTS: Mean agreement between the 2 OCTs as 1.96 × standard deviation of the mean difference between the measurements of central macular subfield was 21 µm in normal eyes and 36.8 µm in abnormal eyes. In five macular subfields, the agreement was significantly better in normal eyes. Cirrus HD-OCT repeatability was significantly better than Stratus in five macular subfields in normal eyes and in six macular subfields in abnormal eyes. The repeatability was significantly better in normal eyes in five macular subfields for Stratus and in three macular subfields for Cirrus HD-OCT. CONCLUSION: The agreement between the two OCTs is low and varies in each macular subfield. Cirrus HD-OCT has shown a better repeatability than Stratus OCT, especially when measuring eyes with a thickened macula.

Anti-vascular endothelial growth factor activity in the bevacizumab and triamcinolone acetonide combination for intravitreal use.

PURPOSE: To find out if the combination for intravitreal use of the antibody bevacizumab (AvastinTM; Genentech, Inc., San Francisco, CA) and triamcinolone acetonide (TA) (Kenacort; Bristol-Myers Squibb, Anagni, Italy) could affect over time the anti -vascular endothelial growth factor (VEGF) activity of bevacizumab. METHODS: Two different combined preparations were obtained, drawing up together 1.25 mg/0.05 mL of bevacizumab and 2 mg/0.05 mL (B+TA(2mg)) or 4 mg/0.05 mL (B+TA(4mg)) of TA into insulin syringes with 29-G needle. Control preparations were obtained with bevacizumab and an injectable solution (B). The syringes were stored refrigerated at 4 degrees C. The bevacizumab concentration was measured, through its binding to VEGF-165 isoform, at 48 hours and at 1 week. RESULTS: No preparations showed statistically significant changes in bevacizumab concentration with time (p=0.74 for B+T(2mg), p=0.92 for B+T(4mg), p=0.57 for B). The B+TA(2mg) preparations showed a larger percentage of degradation of bevacizumab than the B+TA(4mg) preparations (28.4% versus 17.6% at 48 hours; 26.4% versus 18% at 1 week). The B control preparations showed the lowest drug degradation: 9.6% at 48 hours and 14.8% at 1 week. CONCLUSIONS: After storage at 4 degrees C for 48 hours and 1 week, the combined preparations showed a larger reduction in bevacizumab concentration than the control preparations. No significant change was observed with the length of storage. The preparations obtained mixing 4 mg/0.05 mL of TA and 1.25 mg/0.05 mL of bevacizumab maintained the highest anti-VEGF activity over time.

Excimer laser-assisted lamellar keratoplasty for the surgical treatment of keratoconus.

PURPOSE: To evaluate the anatomical and functional results of excimer laser-assisted lamellar keratoplasty (ELLK) in keratoconus patients. SETTING: Eye Clinic, University of L'Aquila, L'Aquila, Italy. METHODS: This prospective case series comprised patients with keratoconus who had ELLK and were examined preoperatively and 3, 6, 12, and 24 months postoperatively. Outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, computerized videokeratography, pachymetry, and endothelial specular microscopy. RESULTS: Forty-one eyes (41 patients) were examined. The UCVA and BSCVA were significantly better at all follow-up examinations than preoperatively. After the 24-month follow-up (33 patients), the UCVA was better than 20/60 in 11 patients (33.3%) and the BSCVA was 20/40 or better in 29 patients (87.9%). The mean refractive astigmatism was 2.20 diopters (D) and the mean manifest refraction spherical equivalent refraction, -1.18 D. Corneal topographic patterns were regularly astigmatic in 28 (84.8%) of 33 eyes, and the mean corneal thickness (440.0 mum) was significantly greater than preoperatively (553.0 mum). No statistically significant changes in mean corneal endothelial cell density were observed postoperatively. Complications included corneal melting treated with penetrating keratoplasty (PKP) (1 case) and postoperative high refractive error requiring topographically guided excimer laser photorefractive keratectomy (7 cases). CONCLUSIONS: Two-year findings indicate that ELLK is as efficacious as PKP for the surgical treatment of moderate to advanced keratoconus. The procedure is relatively simple. Most steps can be standardized, and there are no time-consuming maneuvers.

Comparison of optical low coherence reflectometry and ultrasound pachymetry in the measurement of central corneal thickness before and after photorefractive keratectomy.

PURPOSE: To compare an ultrasound pachymeter with an optical low coherence reflectometry (OLCR) pachymeter for measuring pre- and postoperative central corneal thickness of patients undergoing photorefractive keratectomy (PRK). METHODS: In a prospective, noncomparative, interventional study, 48 myopic eyes (mean manifest refractive spherical equivalent: -4.93 +/- 2.93 diopters [D]) of 30 healthy patients underwent PRK. Pre- and postoperative central corneal thickness was measured by two examiners (E1, E2) with an ultrasound pachymeter and an OLCR pachymeter. Agreement and inter-rater repeatability were determined using the comparison method described by Bland and Altman. RESULTS: The limits of agreement between the two devices ranged from 17.8 microm (E1) to 20.5 microm (E2) preoperatively and from 22.4 microm (E1) to 16.9 microm (E2) postoperatively. The coefficient of inter-rater repeatability ranged from 9.1 microm (ultrasound pachymeter) to 5.4 microm (OLCR pachymeter) preoperatively and from 7.1 microm (ultrasound pachymeter) to 4.7 microm (OLCR pachymeter) postoperatively. CONCLUSIONS: The OLCR pachymeter seems to show better pre- and postoperative repeatability compared to the ultrasound pachymeter. The agreement between the two devices should be considered acceptable for clinical practice. Photorefractive keratectomy did not affect the postoperative agreement and repeatability of the pachymeters.

Immunotherapy with imiquimod 5% cream for eyelid nodular basal cell carcinoma.

PURPOSE: To evaluate the efficacy and safety of topical imiquimod 5% cream for the treatment of eyelid basal cell carcinoma. DESIGN: Two interventional case reports. METHODS: Imiquimod 5% cream was applied topically once daily, 3 days a week for 8 to 12 weeks, in two patients affected by eyelid nodular basal cell carcinoma. Patients were followed up clinically with slit-lamp examination for evidence of tumor disappearance or recurrence, and local and systemic side effects. RESULTS: Complete clinical response was obtained in both patients. No severe local side effects were observed. Patients did not show any local recurrence after 1 year. CONCLUSIONS: Topical imiquimod 5% cream seems to be a useful treatment for eyelid nodular basal cell carcinoma in selected cases, but further long-term studies are needed to assess the efficacy and safety of this approach.

Pre-excimer laser and post-excimer laser refractive surgery measurements of scotopic pupil diameter using 2 pupillometers.

PURPOSE: To compare a digital infrared pupillometer with a handheld light amplification pupillometer for measuring scotopic pupil size and to evaluate if the postoperative refractive changes of the cornea can influence pupil measurements. DESIGN: Prospective noncomparative interventional case series. PARTICIPANTS: One hundred eyes, 50 myopic (mean spherical equivalent [SE] refraction [+/- standard deviation], -4.32+/-2.44 diopters [D]) and 50 hyperopic (mean SE refraction, +2.95+/-0.99 D), of 50 otherwise healthy subjects underwent photorefractive keratectomy or LASIK. INTERVENTION: The preoperative and postoperative scotopic pupil sizes were measured by 2 examiners (E1, E2) with both a handheld light amplification pupillometer (Colvard, Oasis Medical, Glendora, CA) and a digital infrared pupillometer (Eye World Pupillometer [EWP], Oculus Keratograph, Oculus Opikgerate GmbH, Wetzlar, Germany). The agreement and interrater repeatability were determined using the comparison method described by Bland and Altman. The paired Student's t test was used to evaluate the difference between the preoperative and postoperative measurements. MAIN OUTCOME MEASURES: Scotopic pupil diameter, topographic corneal refractive power, uncorrected visual acuity (VA), best spectacle-corrected VA, and manifest spectacle refraction. RESULTS: The preoperative mean scotopic pupil diameter was 6.12+/-0.90 mm with the EWP and 6.18+/-0.91 mm with the Colvard. After the surgery, mean SE refractions were -0.22+/-0.98 D (myopic patients) and +0.19+/-0.40 D (hyperopic patients). Postoperative mean scotopic pupil diameters were 6.12+/-0.89 mm (EWP) and 6.17+/-0.90 mm (Colvard). There was no statistically significant difference between preoperative and postoperative mean scotopic pupil sizes in either patient group. The limits of agreement between the 2 devices ranged from 2.24 mm (E1) to 2.12 mm (E2) preoperatively and from 2.27 mm (E1) to 2.08 mm (E2) postoperatively. The coefficient of interrater repeatability ranged from 0.56 mm (EWP) to 1.12 mm (Colvard) preoperatively and from 0.62 mm (EWP) to 1.14 mm (Colvard) postoperatively. CONCLUSIONS: The digital infrared pupillometer showed better preoperative and postoperative repeatability than the handheld light amplification pupillometer. In the present study, a mean correction of <3 D of the corneal refractive power did not seem to modify the preoperative scotopic pupil size measurements.