Emmetropization and optical aberrations in a myopic corneal refractive surgery chick model.

We studied the potential of myopic corneal refractive laser surgery to induce myopia (axial elongation) and potential interactions between aberrations (generally resulting from the procedure) and myopia development in chicks (Gallus domesticus). Ten white Leghorn chicks were monolaterally treated one day post-hatching with photorefractive keratectomy (PRK), with a nominal dioptric change of -9.9 D (imposed hyperopia). Axial length was measured using an adapted ultrasonic biometer; corneal radius of curvature was measured using a custom-built videokeratometer and spherical error and high order aberrations were measured using custom-built Hartmann-Shack aberrometer post-operatively on days 9, 12, 14 and 16 after hatching. Two-weeks after surgery, there were no significant differences in corneal radius of curvature between treated and control eyes. Astigmatism increased on average by a factor of 2.6 and 3rd and higher order aberrations by a factor of 4.3 after PRK. Both treated and control eyes were close to emmetropia, and no axial elongation was found in the treated eyes. The inability of the refractive procedure to achieve significant reductions in the corneal power could be attributed to the biomechanical properties of the chick eye. High order aberrations induced significant contrast decrease (by a factor of 1.7 at 4.5c/deg). However, reduced image quality neither produced myopic refractive error nor axial elongation in the treated eyes. Both normal and treated eyes emmetropized, indicating that increased amounts of aberrations do not appear to be a risk factor for myopia.

LC-ESI-MSD fast determination of residual mitomycin C in hen aqueous humour after corneal refractive surgery.

A simple, fast and reliable method has been developed for the assay of traces of mitomycin C (MMC) in hen aqueous humour samples. The determination was carried out by high-performance liquid chromatography with electrospray ionization mass spectrometric detection. In isocratic elution analysis, the mobile phase was a mixture of water-acetonitrile (78:22, v/v) and the chromatographic column was C(18) at 35 degrees C. The method has been validated over a range from 0.1 to 250 microg L(-1) in hen aqueous humour with correlation coefficients higher than 0.999. Limit of detection and limit of quantification for MMC based in signal to noise ratio of 3 and 10, respectively, were 20 and 71 ng L(-1). The developed method allows the analysis of MMC in hen aqueous humour samples obtained at different times and conditions in order to evaluate and compare the efficacy of the drug administration.

Keratoconus: an inflammatory disorder?

Keratoconus has been classically defined as a progressive, non-inflammatory condition, which produces a thinning and steepening of the cornea. Its pathophysiological mechanisms have been investigated for a long time. Both genetic and environmental factors have been associated with the disease. Recent studies have shown a significant role of proteolytic enzymes, cytokines, and free radicals; therefore, although keratoconus does not meet all the classic criteria for an inflammatory disease, the lack of inflammation has been questioned. The majority of studies in the tears of patients with keratoconus have found increased levels of interleukin-6 (IL-6), tumor necrosis factor-α(TNF-α), and matrix metalloproteinase (MMP)-9. Eye rubbing, a proven risk factor for keratoconus, has been also shown recently to increase the tear levels of MMP-13, IL-6, and TNF-α. In the tear fluid of patients with ocular rosacea, IL-1α and MMP-9 have been reported to be significantly elevated, and cases of inferior corneal thinning, resembling keratoconus, have been reported. We performed a literature review of published biochemical changes in keratoconus that would support that this could be, at least in part, an inflammatory condition.

Effect of hyaluronic acid on corneal haze in a photorefractive keratectomy experimental model.

PURPOSE: To evaluate the ability of topical hyaluronic acid to decrease corneal opacity after excimer laser photorefractive keratectomy (PRK) in hens. METHODS: Twenty-four white hens underwent bilateral 193-nm excimer laser PRK to correct -9.00 D of myopia. One eye received postoperative treatment with topical 1% hyaluronic acid six times daily for 3 days; the other eye received phosphate buffered saline. Slit-lamp evaluation by a masked observer was performed for 6 months after PRK, and electron microscopy was carried out at the end of the study. RESULTS: There were no significant differences in postoperative haze between the eyes treated with hyaluronic acid and those treated with phosphate buffered saline. CONCLUSION: Topical administration of hyaluronic acid had no effect on the development of corneal haze following PRK in hens.

Automated superficial lamellar keratectomy augmented by excimer laser masked PTK in the management of severe superficial corneal opacities.

AIM: To assess superficial lamellar keratectomy augmented by excimer laser smoothening with sodium hyaluronate 0.25%, for the management of superficial corneal opacities. METHODS: Consecutive procedure performed in 14 eyes (13 patients) with an automated microkeratome and excimer laser phototherapeutic keratectomy (PTK) smoothening using sodium hyaluronate 0.25%. MAIN OUTCOME MEASURES: UCVA, BCVA, pachymetry, degree of haze, ray tracing analysis, and complications. Mean follow up was 12 (SD 1.6) months. RESULTS: Mean preoperative haze from previous corneal refractive surgeries was 3.5 (SD 0.5) (11/14 cases). In one case, opacity was caused by ocular trauma and in two by infectious keratitis. The mean preoperative UCVA was 0.7 logMAR (0.2 (SD 0.13) decimal value). BCVA was 0.4 logMAR (0.4 (SD 0.17) decimal value). Mean preoperative corneal pachymetry was 508 (SD 62.5) micro m and mean opacity depth measured by corneal confocal microscopy was 115.2 (SD 49.4) micro m. At 6 months, 71.4% of the eyes with previous corneal refractive surgery showed grade I haze or less. Mean postoperative corneal pachymetry at 6 months was 352.36 (SD 49.05) micro m. CONCLUSIONS: Automated superficial lamellar keratectomy combined with excimer laser PTK smoothening assisted by sodium hyaluronate 0.25% induces a significant improvement of corneal transparency and visual acuity in cases of corneal opacity caused by previous refractive surgery, ocular trauma, and keratitis.

Five year follow up of biocolonisable microporous fluorocarbon haptic (BIOKOP) keratoprosthesis implantation in patients with high risk of corneal graft failure.

AIM: To study the anatomical and visual performance following implantation of a model of artificial cornea and to evaluate the postoperative long term complications. METHODS: 11 eyes of 11 patients with bilateral corneal blindness considered as potentially having high risk of failure of penetrating corneal keratoplasty were implanted with biocolonisable Kpro keratoprosthesis (BIOKOP I, FCI, Rantigny, France) in the period between January 1996 and May 1998. Only one eye was implanted in all patients and followed up for a period of 60 months. The visual outcome, anatomical and functional stability, complications, and the general performance of the keratoprosthesis were evaluated. RESULTS: The keratoprosthesis (BIOKOP I) only 36.3% remained in position to date. In the patients' last visit five eyes (45.4%) were blind and one (9.0%) showed a slight improvement in the best corrected visual acuity (BCVA) in comparison to preoperative tests. Six eyes (54.5%) showed improved BCVA before having postoperative complications. Four eyes underwent replacement of a BIOKOP I Kpro with a BIOKOP II as a result of extrusion. The keratoprostheses remained anatomically in situ for a mean of 25.5 months and their functional performance period was limited to a mean of 22 months. CONCLUSION: Corneal keratoprosthesis (BIOKOP I, II) does not provide a stable anatomical relation with the surrounding ocular structures. Its ability to restore vision is limited to a short postoperative period in eyes implanted with severe ocular surface disease.

[Glaucoma related with photoreceptor outer segments in aqueous humor. Schwartz-Matsuo syndrome]. / Glaucoma asociado a segmentos externos de fotorreceptores en el humor acuoso (Síndrome de Schwartz-Matsuo).

CASE REPORT: We present the case of a patient who was initially diagnosed of hypertensive uveitis with marked fluctuation that was resistant to the common treatment. After a systematic examination, retinal detachment of the ora serrata in the inferotemporal quadrant was diagnosed. The sample of aqueous humor showed melanic pigment and degenerated photoreceptor outer segments. After retinal detachment surgery, the intraocular pressure returned to normal levels without antiglaucoma medication. DISCUSSION: The presence of photoreceptor outer segments in aqueous humor confirms the diagnosis of Schwartz-Matsuo syndrome, which should be considered as a differential diagnosis of iritis and glaucoma.

Tear proteome and protein network analyses reveal a novel pentamarker panel for tear film characterization in dry eye and meibomian gland dysfunction.

Dry eye and meibomian gland dysfunction are common ocular surface disorders. Discrimination of both conditions often may be difficult given the overlapping of signs and symptoms, and the lack of correlation with clinical parameters. A total of 144 individuals were included in this study. To search for proteome differences, tear proteins were collected by Merocel sponge and analyzed using 2D-PAGE. Comparative tear protein profile analysis indicated changes in the expression levels of fifteen proteins. Subsequent to MALDI-TOF/TOF protein identification, network analysis revealed expression/interaction connections with other proteins, thereby identifying additional putative markers. A screening validation assay demonstrated the discriminative power of six candidate biomarkers. A further validation study using multiplexed-like ELISA assays in tear samples collected with both sponge and capillary confirmed the high discriminatory power of five biomarkers: S100A6, annexin A1 (ANXA1), annexin A11 (ANXA11), cystatin-S (CST4), and phospholipase A2-activating protein (PLAA) with an area under ROC curve (AUC)≥ 97.9% (sensitivity ≥ 94.3%; specificity ≥ 97.6%) when comparing dry eye and control individuals. This panel also discriminated between dry eye, meibomian gland dysfunction and control individuals, with a global correct assignment (CA) of 73.2% between all groups. Correct assignment was not found to be significantly dependent on the tear collection method.

Experimental measurement of corneal haze after excimer laser keratectomy.

We developed a model of corneal haze following photorefractive keratectomy (PRK) in Iber Braun hens and studied optical properties. The animals underwent PRK for -9.0 diopters of myopia and were divided into groups based on treatment with different wound-healing modulators. At different time points postoperatively, we evaluated haze by slit-lamp microscopy. An experimental device was developed to measure transmittance spatial maps and forward scattering of He-Ne laser light in the excised corneas. Subjective and objective haze measures were compared for each group at the different times. Keratocyte densities were determined by optical microscopy and keratocyte sizes by electron microscopy. The agreement between experimental results and a simple numerical model of scattering suggests that increases in stromal keratocyte density after PRK might explain the degree of corneal haze.

Efectividad e impacto en la calidad de vida del colirio de ketotifeno. Resultados del estudio ZETA en pacientes con conjuntivitis alérgica estacional / Effectiveness and impact in the quality of life of ketotifen ophthalmic solution. Results of ZETA study in patients with seasonal allergic conjunctivitis

Objetivos: Estudiar la efectividad del colirio de ketotifeno (0,25 mg/ml) en la conjuntivitis alérgica estacional (CAE) y su impacto en la calidad de vida del paciente. Métodos: Estudio multicéntrico, longitudinal, prospectivo, en el que participaron 284 oftalmólogos de todo el territorio Español reclutando consecutivamente 1145 pacientes con CAE, y tras obtener su consentimiento, les instilaban una gota de colirio de ketotifeno. En la visita se evaluó la sintomatología clínica pre y post-tratamiento. Los pacientes respondieron un cuestionario de calidad de vida (CVRS) pre-tratamiento y como mínimo a la semana de haber iniciado el tratamiento. Las variables cualitativas se describieron mediante porcentajes y las cuantitativas con la media, la mediana, la desviación estándar, los valores máximos y los mínimos. Se estudió la efectividad (cambio de intensidad de los síntomas) y la calidad de vida mediante el test de Wilcoxon con significación del 5 por ciento (alfa = 0,05). Resultados: Tras la instilación, la intensidad de la clínica ocular (hiperemia, edema, lagrimeo, secreción, fotofobia y trastorno de agudeza visual) disminuyó significativamente. Comparando ambos CVRS, se observó un descenso estadísticamente significativo de la limitación percibida por el paciente, de la afectación del estado anímico, y de los síntomas oculares. En el 0’7 por ciento se refirió algún acontecimiento adverso, ninguno grave, y en sólo un caso se especificó la probable relación con el fármaco. Conclusiones: El colirio de ketotifeno, en el estudio ZETA, muestra tolerabilidad y efectividad frente a todos los síntomas de la CAE en condiciones reales de uso, observando mejoría en la calidad de vida del paciente (AU)

Purpose: To study the effectiveness of ketotifen ophthalmic solution (0.25 mg/ml) in seasonal allergic conjunctivitis (SAC) and the impact on the patient’s quality of life. Methods: A multicentric, longitudinal, prospective study was designed. 284 Spanish ophthalmologists participated recruiting 1145 patients with SAC. After obtaining the informed consent, a drop of ketotifen ophthalmic solution was instilled. At the visit, clinical symptoms pre and post-treatment were assessed. The patients answered a questionnaire of quality of life (QOL) pre-treatment and minimum one week after initiating the treatment. The qualitative variables were described by the percentage, and the quantitative were described by the average, median, standard deviation, and maximum and minimum values. The effectiveness (change of intensity of the symptoms) and the quality of life were studied by the Wilcoxon test with a significance level of 5% (α= 0.05). Results: Following the instillation of the ketotifen ophthalmic solution the intensity of the ocular symptoms (redness, edema, tearing, secretion, photophobia and visual acuity impairment) decreased significantly. Comparing both QOL, we observed a statistically significant reduction of the limitation perceived by the patients in their daily activities, animic state and ocular symptoms. In 0,7% some adverse event was referred, none was serious and only in one case the probable relationship with the drug was specified. Conclusion: The results of the ZETA study demonstrate the tolerability and effectiveness of the ketotifen ophthalmic solution for all the symptoms of SAC in clinical practice, observing improvement in the quality of life of the patient (AU)

Glaucoma asociado a segmentos externos de fotorreceptores en el humor acuoso (síndrome de Schwartz-Matsuo) / Glaucoma related with photoreceptor outer segments in aqueous humor (Schwartz-Matsuo syndrome)

Caso clínico: Presentamos el caso de un paciente diagnosticado inicialmente de uveítis hipertensiva fluctuante y resistente al tratamiento habitual. Tras una exploración sistemática se descubrió un desprendimiento plano de la ora serrata en el cuadrante inferotemporal. La muestra de humor acuoso evidenció pigmento melánico y tilacoides desestructurados. Tras la cirugía del desprendimiento de retina la presión volvió a niveles normales sin medicación antiglaucomatosa. Discusión: La presencia de segmentos externos de fotorreceptores en humor acuoso confirmó el diagnóstico de síndrome de Schwartz-Matsuo, el cual debe considerarse en el diagnóstico diferencial de la iritis y el glaucoma. (AU)