Evolution of corneal thickness and optical density after laser in situ keratomileusis versus small incision lenticule extraction for myopia correction.

PURPOSE: To compare the thickness and stromal optical density (OD) evolution of the flap and cap after femtosecond (FS-LASIK; Visumax) and small incision lenticule extraction (SMILE), respectively, for myopia correction. METHODS: A prospective study comprising 78 eyes (n=39 per group) was performed. Anterior segment optical coherence tomography (MS39) images were collected at each postoperative visit (1 day, 1 week and 1 and 3 months) and flap/cap thicknesses were measured. Using ImageJ software, three regions were defined to measure OD (in grayscale units: flap/cap stroma, residual stromal bed (RSB) and all stroma (including flap/cap-stroma, surgical interface and RSB). RESULTS: Mean central thickness significantly increased during the 3-month follow-up in both LASIK (5.43±4.23 µm; p=0.0118) and SMILE (2.76±5.61 µm; p=0.0118), with differences between both techniques statistically significant (p=0.020). All OD values showed a statistically significant reduction during SMILE follow-up: cap 48.96±5.55 versus 44.95±5.41 (p=0.19×10-6), RSB 50.26±7.06 versus 45.42±7.53 (p=0.00005), total stroma 50.34±6.49 versus 45.46±6.96 (p=0.5×10-5) at 1 day and 3 months, respectively, whereas no statistically significant changes were found during LASIK follow-up. No significant differences were observed in OD values between both techniques at any time point, although SMILE showed a tendency for higher OD values than LASIK within the first postoperative month. Visumax presented a tendency for thicker caps than target (11.48±7.85 µm), but not for flaps (2.73±8.93 µm) (p=0.00003). CONCLUSIONS: Both LASIK flaps and SMILE caps show a significant postoperative rethickening. SMILE corneas present higher optical densities than LASIK corneas in the early postoperative period, with a significant decrease thereafter and up to 3 months. These findings correlate with the delayed visual recovery observed after SMILE.

Effect of flap homogeneity on higher-order aberrations induction after femtosecond LASIK for myopia.

PURPOSE: To assess the relevance of the homogeneity of femtosecond laser flap thickness regarding induction of higher-order aberrations (HOAs). SETTING: Clínica Rementería & Clínica Novovisión, Madrid, Spain. DESIGN: Prospective observational study. METHODS: Two hundred thirty-one patients underwent in situ keratomileusis using 5 different femtosecond lasers. The flap thicknesses were measured using anterior segment optical coherence tomography 3 months postoperatively. The same masked observer measured 6 symmetrical points nasally and temporally 1.0 mm, 2.0 mm, and 3.0 mm from the center of the flap in each case. HOAs induced in the cornea were measured using tomography. RESULTS: Positive and significant correlations were found between HOA induction and the flap thickness heterogeneity 3.0 mm from the center of the flap. Pearson correlation coefficients for the induction of HOAs were third-order 0.17112 (P = .0224), fourth-order 0.22474 (P = .0026), fifth-order 0.16449 (P = .0282), coma-like 0.17370 (P = .0204), and total HOAs 0.18182 (P = .0151). CONCLUSIONS: The amount of flap-thickness heterogeneity at 3.0 mm from the center of the flap created using femtosecond lasers was correlated with the magnitude of the HOAs induced.

Evolution of visual acuity, flap thickness, and optical density after laser in situ keratomileusis performed with a femtosecond laser.

PURPOSE: To describe the postoperative evolution of visual acuity, flap morphology, and stromal optical density femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). SETTING: Clínica Rementería, Madrid, Spain. DESIGN: Prospective case series. METHODS: The study comprised 44 consecutive eyes that had FS-LASIK performed with the WaveLight FS200 and the Allegretto excimer laser to correct myopia. Visual outcomes, flap thickness, and stromal optical density were assessed 1 day, 1 week, 1 month, and 3 months postoperatively. RESULTS: A statistically significant improvement in the mean uncorrected distance visual acuity at 1 day (0.94 ± 0.2) and 1 week (0.93 ± 0.2) to 1 month (1.04 ± 0.2) and 3 months (1.11 ± 0.1) postoperatively (P < .05). At 3 months postoperatively, the femtosecond laser had good outcomes in efficacy (0.98 ± 0.1), safety (0.98 ± 0.1), and predictability (100% of eyes were within ± 0.5 D of emmetropia). The femtosecond-created flaps were slightly thicker than intended, the mean SD intraflap was 7.1 µm, the range between the thickest and thinnest points in each flap was 25.4 µm, and the mean flap thickness homogeneity was 7.6 µm at 3 months postoperatively. A progressive decrease in the optical density of the flap stroma and the residual stromal bed was detected during follow-up. CONCLUSIONS: The femtosecond laser study appears to be a safe, effective, and predictable platform to obtain LASIK flaps. The flaps were planar and homogeneous but slightly thicker than intended. The optical density of the flap stroma was slightly higher at early follow-up and decreased over time.

Analysis of corneal stromal roughness after iFS 150 kHz and LenSx femtosecond LASIK flap creation in porcine eyes.

PURPOSE: To describe and compare the stromal bed roughness obtained after laser in situ keratomileusis (LASIK) flap creation using a corneal femtosecond laser platform (iFS 150) and a "dual" femtosecond (FS) laser platform (LenSx). METHODS: This ex vivo experimental study was conducted in an animal model using 12 freshly enucleated porcine eyes, six with each femtosecond laser. The standard laser treatment parameters were used for the experiment. After LASIK flap creation, the corneal stromal roughness was assessed using atomic force microscopy (AFM) in contact mode immersed in liquid. In each sample, surface measurements were obtained in 60 regions of six eyes per FS laser in 10 20 × 20-micron areas of the central corneal stroma at 512 × 512-point resolution. The surface roughness was measured and the root-mean-square (RMS) values of the roughness were obtained. RESULTS: The mean RMS ± standard deviation values were 430 ± 150 nm for the corneal femtosecond laser platform and 370 ± 100 nm for the dual FS laser platform (P < 0.011). CONCLUSIONS: In this experimental study with AFM, we found smoother stromal beds after LASIK flap creation with LenSx compared to iFS 150 kHz. Further studies are needed to understand visual implications of the differences found.

Two Femtosecond Laser LASIK Platforms: Comparison of Evolution of Visual Acuity, Flap Thickness, and Stromal Optical Density.

PURPOSE: To compare postoperative evolution of visual acuity, flap thickness, and stromal optical density during the first 3 months after femtosecond (FS) laser in situ keratomileusis surgery for correction of myopia using the iFS 150-kHz FS laser and LenSx FS laser platforms. METHODS: This was a prospective case series. Thirty-nine eyes treated with the iFS 150-kHz FS laser versus 38 refraction-matched eyes treated with the LenSx FS laser platform were included. Visual outcomes, flap morphology, and optical density of the stroma (in both flap and residual stromal bed) were compared at 4 visits during a three-month follow-up period. RESULTS: No significant differences were found in uncorrected distance visual acuity in any of the follow-up visits (1 day -0.02 vs. -0.03; 1 week -0.04 vs. -0.03; 1 month -0.04 vs. -0.04; 3 months -0.03 vs. -0.05 logarithm of the minimum angle of resolution). Flaps created with the iFS 150-kHz FS laser were closer to the intended thickness (110 µm) in every postoperative comparison (1 day 108.6 vs. 124.3; 1 week 107.6 vs. 123.6; 1 month 110.4 vs. 126.8; 3 months 116.2 vs. 126.5 µm; P < 0.0001). Dispersion of values, standard deviation, intraflap range, and differences in symmetric points were lower in the iFS 150-kHz FS laser group. Flap stromal optical density was significantly higher in the LenSx FS laser group at day 1 and week 1 (134.5 vs. 158.9 gray scale unit [GSU]; P < 0.0001 and 144.8 vs. 160.1 GSU; P = 0.011, respectively). Residual stromal bed optical density was higher in the LenSx FS laser group at all postoperative visits, and the differences reached significance at 1 week postoperatively (121.9 vs. 135.4 GSU; P = 0.03). CONCLUSIONS: Although both devices provided satisfactory visual outcomes, significant differences were detected in flap parameters. Flaps made with the iFS 150-kHz FS laser were thinner, more uniform, transparent, and accurate compared with those obtained with the LenSx FS laser.

Incidence and Risk Factors of Dry Eye in a Spanish Adult Population: 11-Year Follow-Up From the Salnés Eye Study.

PURPOSE: To estimate the incidence of dry eye (DE) and to evaluate risk factors in an adult cohort in Spain. METHODS: The Salnés Eye Study (SES) was a cross-sectional population-based study of 654 subjects conducted from 2005 to 2006. After 11 years, 264 individuals (65.8% response rate) participated in SES 2. The incidence cohort consisted of 209 subjects not diagnosed with DE in SES 1 [mean age (SD) 67.6 years (±10.1), range: 51-92, women 69.4%]. DE was defined as the simultaneous presence of symptoms and at least 1 sign. A Schirmer test score ≤5 mm, tear film breakup time ≤10 seconds, rose bengal staining ≥3, and fluorescein staining ≥1 were considered indicative of signs. Poisson regression models were performed to evaluate risk factors. RESULTS: The 11-year incidence of DE was 25.4% (95% confidence interval, 19.5-31.3) and that of symptoms was 31.6% (confidence interval, 25.4-37.8). DE incidence was significantly associated with age (P < 0.05). After adjusting for age, secondary or university studies were protective factors for DE; taking anxiolytics or antidepressants and angiotensin-converting enzyme inhibitors increased the risk of symptoms; a history of hypertension, chronic obstructive pulmonary disease, or autoimmune diseases increased the risk of signs. CONCLUSIONS: The annual incidence of DE, symptoms, and signs, was found to be 2.3 per 100 person-years. The incidence of symptoms was higher than that reported in similar studies. This study suggests that some factors may increase the risk of symptoms, whereas other factors may increase the risk of signs.

Early treatment of tuberculous uveitis improves visual outcome: a 10-year cohort study.

PURPOSE: Diagnosis of tuberculous uveitis (TBU) is often challenging and is usually made after excluding other causes of uveitis. We analysed the characteristics of TBU and variables associated with visual outcome. METHODS: A retrospective, observational analysis was performed in patients with presumptive TBU who were started on specific TB treatment between January 2006 and June 2016. Demographic, clinical, radiological, analytical and ophthalmic examination variables were studied. After completing TB treatment, a follow-up of at least 9 months was performed. A univariate and logistic regression analysis was applied to identify the variables associated with visual acuity and recurrences of uveitis. RESULTS: Forty affected eyes of 24 individuals were identified; 79% of patients were diagnosed during the last 3 years of the study period. Median delay from onset of symptoms to diagnosis was 12 weeks. Loss of visual acuity was the most frequent symptom (87.5%). Posterior uveitis was the most frequent localization (72.9%); 19 patients (79.2%) presented at least one of the Gupta signs predictive of TBU, but there were no confirmed diagnoses. OUTCOME: There was improvement in visual acuity in 74.4% of the eyes, but a complete response was achieved only in 56.4%. There was recurrence in two patients. The initiation of treatment ≥ 24 weeks after onset of symptoms was significantly associated with no improvement (p = 0.026). CONCLUSION: TBU can cause permanent damage to visual acuity, particularly in patients with delayed diagnosis. A prompt initiation of systemic TB treatment is essential to improve visual prognosis.

Comparison of visual outcomes and flap morphology using 2 femtosecond-laser platforms.

PURPOSE: To compare the 3-month postoperative refractive results and flap thickness homogeneity after correction of myopia using the Intralase femtosecond platform and the Victus dual femtosecond laser platform. SETTING: Novovision Clinic, Madrid, Spain. DESIGN: Prospective case series. METHODS: Eyes treated with a 60 kHz femtosecond laser (Group 1) and eyes treated with a dual femtosecond laser (Group 2) were included. The refractive results 3 months postoperatively were compared. The differences between the maximum and the minimum thickness point of each flap, the intraflap standard deviation (SD), and the achieved and the targeted central flap thickness were evaluated in each group. RESULTS: The study comprised 31 eyes in Group 1 and 20 eyes in Group 2. Three months postoperatively, the uncorrected distance visual acuity, residual refraction, efficacy, safety, and predictability were significantly better in Group 1. The dual femtosecond laser induced a significantly greater increase in higher-order aberrations than the conventional femtosecond laser. The mean central flap thickness was 123.2 µm ± 9.2 (SD) in Group 1 and 116.3 ± 14.4 µm in Group 2 (P = .005). The mean difference between the maximum and the minimum flap thickness points in each flap was significantly lower in Group 1 than in Group 2 (22 ± 8.3 µm versus 35.7 ± 16.9 µm) (P = .0007). The intraflap SD was significantly lower in Group 1 than in Group 2 (6.1 µm versus 10.8 µm) (P = .0001). CONCLUSION: The conventional femtosecond laser provided better efficacy, safety, predictability, and flap thickness homogeneity than the dual femtosecond laser for the correction of myopia.

Foster Kennedy Syndrome: An Atypical Presentation.

PURPOSE: To describe an unusual presentation of Foster Kennedy syndrome (FKS; unilateral optic nerve atrophy with optic nerve edema in the other eye) with optic nerve atrophy and retinal vein occlusion. It is an example of how common clinical features can hide a rare condition or presentation of a disease. Foster Kennedy syndrome is uncommon. Therefore, a space-occupying lesion should be suspected when there is optic atrophy associated with acute pathology of the other eye. CASE REPORT: A 56-year-old man presented with hemiretinal retinal vein occlusion in his right eye. He had previous optic nerve atrophy in his left eye attributed to nonarteritic anterior ischemic optic neuropathy. He lacked cardiovascular or prothrombotic risk factors. Consideration was given whether the presence of contralateral optic atrophy was associated with the retinal vein occlusion. A computed tomographic scan revealed a suprasellar mass. The tumor was excised and identified as meningioma. CONCLUSIONS: Although typical FKS would present with optic nerve atrophy and contralateral optic nerve edema secondary to an intracranial mass, in this case, edema was replaced by a hemiretinal vein occlusion. In optic atrophy that does not show characteristic visual field alterations, typical symptoms, or the classic evolution of a given disease, diagnostic imaging may reveal the etiology. As FKS is uncommon, when there is optic atrophy associated with acute pathology of the other eye, a space-occupying lesion should be suspected.

Bilateral Iritis after Vaccine for Bladder Cancer.

PURPOSE: Bacille Calmette-Guérin (BCG) is a vaccine that can be instilled into the urinary bladder as immunotherapy against superficial bladder cancer. Several case reports have implicated intravesical BCG in the development of uveitis. Patients treated with BCG therapy may present with systemic symptoms resembling reactive arthritis and, less frequently, have ocular adverse effects including bilateral panuveitis or chorioretinitis. In all but three previously reported cases of uveitis associated with BCG treatment, HLA-B27 has been positive. No patients have been reported to be positive for rheumatoid factor or antinuclear antibody (ANA). CASE REPORT: An HLA-B27-negative and low-positive ANA patient presented with bilateral uveitis after treatment with BCG therapy for superficial bladder cancer. CONCLUSIONS: There is a need for greater awareness among urologists, primary care physicians, and optometrists of the potential for BCG to cause uveitis. These doctors should look for indicators of uveitis, such as circumlimbal conjunctival injection, photophobia, irregular pupils, and keratic precipitates. Together with appropriate treatment or prompt referral, this could prevent unnecessary morbidity. Future studies are needed to further elucidate the possible reasons for ANA positivity in these patients and the future role of the test in diagnosis and management.