RESUMEN
PURPOSE: To report one-year outcomes of a modified version of two-stage multimodal surgical protocol for moderate keratoconus which has been suggesting promising preliminary results. MATERIALS AND METHODS: 30 eyes of 25 patients with moderate keratoconus who exhibited visual complaints and/or disease progression were included for this retrospective case study. Approximately 3 months after implantation of intracorneal ring segment (Intacs SK™), a combination of corneal wavefront-guided transepithelial photorefractive keratectomy (CWG-transPRK, Schwind Amaris® 1050, and Schwind Sirius) and accelerated collagen cross-linking (accCXL, Avedro KXL™) was performed. Patients were examined for uncorrected and corrected distance visual acuity (UDVA; CDVA), keratometric power (K), corneal thickness, and corneal higher-order aberrations (HOAs) preoperatively and at postoperative 1, 3, 6, and 12 months. RESULTS: The median UDVA and mean CDVA were enhanced from 6/38 to 6/12 and from 6/19 to 6/7.5, respectively, through 12 months after CWG-transPRK/accCXL. The 12-month CDVA of all patients was better than 6/12 Snellen, and no subject lost one or more lines of CDVA. The magnitudes of both myopia and corneal steepness were decreased in turn by Intacs SK implantation and also by CWG-transPRK/accCXL, but the reduction in HOA was largely the result of CWG-transPRK/accCXL. The magnitude of corneal thinning stabilized within 3 months after CWG-transPRK/accCXL. CONCLUSION: This approach may allow patients with moderate keratoconus to obtain satisfactory vision without the need for contact lens wear. This surgery appeared to be effective and safe through 1 year of follow-up.
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Colágeno/metabolismo , Sustancia Propia , Topografía de la Córnea , Queratocono , Queratectomía Fotorrefractiva , Seguridad , Agudeza Visual , Adulto , Sustancia Propia/diagnóstico por imagen , Sustancia Propia/metabolismo , Sustancia Propia/fisiopatología , Sustancia Propia/cirugía , Femenino , Estudios de Seguimiento , Humanos , Queratocono/diagnóstico por imagen , Queratocono/metabolismo , Queratocono/fisiopatología , Queratocono/cirugía , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
PURPOSE: To suggest that tear film is a refractive outcome predictor in small-incision lenticule extraction (SMILE) for myopia and describe methods of controlling the tear film and its effects on refractive outcomes. METHODS: In this retrospective case-control study, the tear film was kept clear and appropriate in amount during tear-film-controlled SMILE (TFC-SMILE). In contrast, no special care to the tear film was given in direct-docking SMILE (DD-SMILE). Both procedures were performed by the same experienced surgeon, using the same surgical parameters, over defined periods. In select cases, scanning electron microscopy (SEM) of the lenticule and surgical videos of opaque bubble layers (OBLs) were obtained and compared. RESULTS: Forty-one eyes had DD-SMILE and 55 eyes had TFC-SMILE. Multivariate analysis showed that TFC-SMILE and the patient's age were significant predictors of refractive outcomes. The refractive predictability of TFC-SMILE was better than that of DD-SMILE, and under-correction of high myopia was evident in the latter patients. The predictive errors of DD-SMILE became more myopic and variable during 1 year than those of TFC-SMILE. The lenticular surface on SEM was more serrated in DD-SMILE. Severe OBLs were evident in four cases of DD-SMILE and the OBL pattern was sporadic at the anterior surface of the lenticule. CONCLUSIONS: The presence of a clear and appropriate tear film in SMILE enhanced predictability, minimized variability, and ensured stability of refractive outcomes. An uncontrolled tear film might render cutting imprecise and trigger severe OBL formation. TFC-SMILE had more predictable results than DD-SMILE.
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Cirugía Laser de Córnea/métodos , Miopía/cirugía , Refracción Ocular/fisiología , Lágrimas/fisiología , Adulto , Estudios de Casos y Controles , Sustancia Propia/cirugía , Topografía de la Córnea , Femenino , Humanos , Masculino , Microscopía Electrónica de Rastreo , Microcirugia , Miopía/fisiopatología , Estudios Retrospectivos , Agudeza Visual/fisiología , Adulto JovenRESUMEN
A 49-year-old man with an uncorrected visual acuity (UCVA) of 20 / 1000, a best spectacle-corrected visual acuity (BSCVA) of 20 / 400, keratometric readings of K1 = 59.88 × 82° / K2 = 45.88 × 172°, and an inferior steepening that was consistent with keratoconus in his left eye was treated with clear-cornea phacoemulsification and an intraocular lens (IOL) implantation after insertion of keraring intrastromal corneal ring segments for severe keratoconus and cataract. An asymmetrical pair of kerarings was implanted with the assistance of a femtosecond laser in September 2008; the one segment was 250 µm and the other was 150 µm and both were placed at 70°. Three months after the kerarings were implanted, clear-cornea phacoemulsification and IOL implantation were performed on the left eye. After surgery, both the UCVA and the BSCVA of the left eye improved by eight lines. Postoperative central keratometry showed a decrease of 7.35 diopters in the left eye. Both the postoperative refraction (-0.75 -0.75 × 60°) and the keratometric reading (K1 = 50.05 × 93° / K2 = 48.83 × 3°) remained stable one month following the procedures. Thus, the sequential order of intrastromal corneal rings implantation and cataract surgery can be considered as a treatment option in patients with severe keratoconus and cataract.
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Catarata/complicaciones , Sustancia Propia/cirugía , Queratocono/cirugía , Implantación de Lentes Intraoculares/métodos , Facoemulsificación/métodos , Catarata/diagnóstico , Sustancia Propia/patología , Topografía de la Córnea , Estudios de Seguimiento , Humanos , Queratocono/complicaciones , Queratocono/diagnóstico , Masculino , Persona de Mediana Edad , Índice de Severidad de la EnfermedadRESUMEN
PURPOSE: To determine the reproducibility of morphoscopic contrast sensitivity test values in healthy subjects using the Visual Capacity Analyzer (VCA) (L2 Informatique). SETTING: Institute of Vision Research, Department of Ophthalmology, Yong-Dong Severance Hospital, Yonsei University, Seoul, South Korea. METHODS: Five healthy volunteers were recruited for this study. With the VCA, 1 eye of each person was tested with different sized letters displayed on a computer screen at 11 spatial frequencies ranging from low (3.0 cycles/deg [cpd]) to high (30.0 cpd). The measurement was repeated 5 times under 2 screen luminance levels (maximum and 3 cd/m2). RESULTS: Under maximum luminance background, the coefficient of variation (CV) and reliability coefficient (RC) at the spatial frequencies examined ranged from 4.3% to 35.0% and 89.1% to 99.8%, respectively. Under a screen luminance of 3 cd/m2, the CV ranged from 0.5% to 15.9% and the RC, from 97.5% to 100.0%. CONCLUSION: At the spatial frequencies examined, morphoscopic contrast sensitivity testing using the VCA had a high level of reproducibility and may be useful in measuring a patient's visual function in the actual environment.