RESUMEN
IMPORTANCE: It is unknown whether a neurotrophic deficit or pathologic nerve morphology persists in keratoconus in the long term after corneal collagen cross-linking (CXL) treatment. Nerve pathology could impact long-term corneal status in patients with keratoconus. OBJECTIVE: To determine whether CXL treatment of keratoconus results in normalization of subbasal nerve density and architecture up to 5 years after treatment. DESIGN, SETTING, AND PARTICIPANTS: Observational study of 19 patients with early-stage keratoconus indicated for a first CXL treatment with longitudinal follow-up to 5 years postoperatively (examinations were performed from 2009 to 2015; analysis was performed from February to May 2015) and 19 age-matched healthy volunteers at a primary care center and a university hospital ophthalmology department. EXPOSURE: The patients with keratoconus underwent standard epithelial-off UV-A/riboflavin CXL treatment with 30-minute UV-A exposure at 3 mW/cm2 irradiance. MAIN OUTCOMES AND MEASURES: Central corneal subbasal nerve density and subbasal nerve architecture by use of laser-scanning in vivo confocal microscopy; subbasal nerve analysis by 2 masked observers and by use of a fully automated method; wide-field mosaics of subbasal nerve architecture by use of an automated method; and ocular surface touch sensitivity by use of contact esthesiometry. RESULTS: Mean (SD) age of the 19 patients with keratoconus was 27.5 (7.1) years (range, 19-44 years), and minimal corneal thickness was 428 (36) µm (range, 372-497 µm). Compared with the mean (SD) preoperative subbasal nerve density of 21.0 (4.2) mm/mm2 in healthy corneas, the mean (SD) preoperative subbasal nerve density of 10.3 (5.6) mm/mm2 in the corneas of patients with stage 1 or 2 keratoconus was reduced 51% (mean difference, 10.7 mm/mm2 [95% CI, 6.8-14.6 mm/mm2]; P < .001). After CXL, nerves continued to regenerate for up to 5 years, but nerve density remained reduced relative to healthy corneas at final follow-up (mean reduction, 8.5 mm/mm2 [95% CI, 4.7-12.4 mm/mm2]; P < .001) despite recovery of touch sensitivity to normal levels by 6 months. Preoperatively, more frequent nerve loops, crossings, and greater crossing angles were observed in the corneas of patients with keratoconus compared with healthy corneas. Postoperatively, the frequency of nerve looping increased, crossings were more frequent, and nerve tortuosity increased. Wide-field mosaics indicated persistent disrupted orientation of the regenerating subbasal nerves 5 years after CXL. CONCLUSIONS AND RELEVANCE: Keratoconus is characterized by a neurotrophic deficit and altered nerve morphology that CXL treatment does not address, despite providing a positive biomechanical effect in the stroma. Given the widespread use of CXL in the management of patients with keratoconus, the progression of abnormal innervation after CXL should be recognized.
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Colágeno/metabolismo , Córnea/inervación , Reactivos de Enlaces Cruzados , Queratocono/tratamiento farmacológico , Queratocono/fisiopatología , Regeneración Nerviosa/fisiología , Nervio Trigémino/fisiología , Adulto , Paquimetría Corneal , Sustancia Propia/metabolismo , Técnicas de Diagnóstico Oftalmológico , Femenino , Estudios de Seguimiento , Voluntarios Sanos , Humanos , Queratocono/metabolismo , Masculino , Microscopía Confocal , Fármacos Fotosensibilizantes/uso terapéutico , Estudios Prospectivos , Riboflavina/uso terapéutico , Rayos Ultravioleta , Adulto JovenRESUMEN
BACKGROUND/AIMS: To evaluate the alterations of mean foveal thickness (MFT) and visual acuity (VA) outcomes after uncomplicated cataract surgery in different groups of patients. METHODS: This study included eyes of consecutive patients who underwent cataract surgery between November 2007 and June 2009. The patients included in the study were divided into 4 groups, as follows: history-free patients, patients with diabetes mellitus without macular involvement at baseline, patients with glaucoma, and patients with epiretinal membrane (ERM). Preoperatively and at 1, 3 and 6 months postoperatively, patients were evaluated for MFT by optical coherence tomography at the central 1-mm macular zone and for logarithm of the minimum angle of resolution best spectacle-corrected VA (BSCVA). RESULTS: A total of 202 eyes were included in the study. MFT values demonstrated a statistically significant increase (p < 0.01) after cataract surgery in all groups at the first and third postoperative month. The history-free (p = 0.09) and glaucoma (p = 0.19) groups did not demonstrate a statistically significant difference in MFT values between the preoperative and 6-month measurements. MFT values 6 months after cataract surgery in the diabetes and ERM groups remained significantly higher (p < 0.01). Despite these findings, VA increased significantly (p < 0.01) in all groups at all postoperative follow-ups. CONCLUSIONS: MFT values increased significantly in all groups at the first and third months after cataract surgery. At 6 months, MFT values returned to preoperative levels in the history-free and glaucoma patients, while they remained significantly higher in the diabetic and ERM patients. Despite these macular alterations, BSCVA improved significantly after cataract surgery in all groups at all postoperative follow-ups.
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Fóvea Central/patología , Implantación de Lentes Intraoculares , Facoemulsificación , Complicaciones Posoperatorias , Enfermedades de la Retina/etiología , Adulto , Anciano , Anciano de 80 o más Años , Diabetes Mellitus/etiología , Membrana Epirretinal/etiología , Femenino , Glaucoma/etiología , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Enfermedades de la Retina/diagnóstico , Tomografía de Coherencia Óptica , Agudeza Visual/fisiologíaRESUMEN
We present a case of a retinal hole detected after routine cataract surgery and discuss possible pathogenetic mechanisms of this complication.