Cambios fisiológicos de la córnea en respuesta al uso de ortoqueratología nocturna

Tesis de la Universidad Complutense de Madrid, Escuela Universitaria de Óptica, Departamento de Óptica II (Optometría y Visión), leída el 12-11-2010Depto. de Optometría y VisiónFac. de Óptica y OptometríaTRUEpu

Biomechanical properties in corneal refractive therapy during adaptation period and after treatment interruption: A pilot study

AbstractPurposeTo evaluate the potential influence and treatment-related changes of the corneal biomechanical properties (BMP) measured with the Ocular Response Analyzer (ORA, Reichert, Depew, NY) 15-days and 1-month after the initiation and cessation of corneal refractive therapy (CRT).MethodsTwenty-four young healthy subjects (24.04±3.19 years) participated in two different experiments. In the first one (#1), twelve right eyes from 12 subjects who were fitted with CRT lenses were evaluated after 15 days and 1 month of lens wear. In the second trial (#2) 12 subjects who had been wearing CRT lenses for a period of 1 year were evaluated at 15 days and 1 month after treatment interruption.ResultsThere was no statistically significant correlation between baseline BMP and absolute values of structural corneal parameters at 15 and 30 days treatment, and also when these variables were normalized according to the targeted refraction. In experiment #1, Corneal hysteresis (CH) reduction was observed over the time of treatment (p=0.019), but no significant differences were observed in the Corneal Resistance Factor (CRF) values. In addition, CRF reduction significantly correlated with spherical equivalent refraction (r=0.597; p=0.044), but no correlation was observed between CH or CRF reduction and the spherical component of the refraction. In experiment #2, no significant changes in CH or CRF were found initially after lens wear interruption, but a trend to increase was observed thereafter.ConclusionCH decreases during onset of the CRT after 30 days of lens wear. Such changes seem to be reversible after cessation of contact lens wear following 1 year of treatment. Corneal biomechanics, however, do not predict the outcomes of CRT in clinical setting although with the data obtained some correlative tendencies were observed that may merit further investigation

Tear Film Osmolarity in Response to Long-Term Orthokeratology Treatment

Purpose: To compare tear film osmolarity (TFO) measurements in non-contact lens (CL) wearers and wearers of hydrogel or overnight orthokeratology (OK) CLs, and to assess possible effects of long-term OK on TFO. Methods: Overall, 108 subjects with moderate myopia participated in 2 experiments, and TFO was measured using the TearLab osmolarity system. In experiment 1, TFO measurements were made in 77 right eyes of 23 non-CL wearers, 26 hydrogel wearers, and 28 OK wearers. Subjects in the last 2 groups had worn their CL for at least 3 years. In experiment 2, 31 individuals (habitual soft CL wearers) were enrolled for prospective long-term follow-up of OK treatment. These subjects were fitted with Paragon-CRT (n=16) or Seefree (n=15) lenses, and TFO readings were taken at baseline and after 1 month and 1 year of lens wear and after 1 month of OK treatment interruption. Results: Values of TFO were within the normal limits in all 3 subject groups, although significantly lower osmolarities (P<0.01) were observed in non-CL wearers (281.7+/-5.9 mOsm/L) compared with hydrogel (291+/-16.5 mOsm/L) or OK lens wearers (301.7+/-10.8 mOsm/L). In experiment 2, TFO differed significantly at baseline between the Paragon-CRT and Seefree groups (P<0.05), and a significant decrease in TFO compared with baseline (P<0.01) was observed in the Paragon-CRT group after 1 month of cessation of lens wear. Conclusion: Higher TFO values were observed in lens wearers (hydrogel or OK) than non-CL wearers. After interruption of OK treatment, TFO returned to similar values to those found in non-CL wearers

Short-term Effects of Overnight Orthokeratology on Corneal Sub-basal Nerve Plexus Morphology and Corneal Sensitivity

Objective: To assess the effects of a short period of orthokeratology (OK) on corneal subbasal nerve plexus (SBNP) morphology and corneal sensitivity. Methods: Measurements were made in 56 right eyes of 56 subjects with low-to-moderate myopia who wore 2 OK lens designs (Group CRT: HDS 100 Paragon CRT, n=35; Group SF: Seefree; n=21) for a period of 1 month and in 15 right eyes of noncontact lens wearers as controls. The variables determined in each participant were corneal sensitivity using a Cochet-Bonnet esthesiometer and 12 SBNP variables determined on laser scanning confocal microscopy images using 3 different software packages. Correlation between SBNP architecture and corneal sensitivity was also examined. Results: Few changes were observed over the 1-month period in the variables examined in the OK treatment and control groups. However, significant reductions were detected over time in the number of nerves in the central cornea in the groups CRT (P=0.029) and SF (P=0.043) and in central corneal sensitivity in CRT (P=0.047) along with significant increases in central and midperipheral corneal Langerhans cell counts in SF (P=0.001 and 0.048, respectively). Conclusions: This study provides useful data to better understand the anatomical changes induced by OK in corneal SBNP. The different response observed to the 2 OK lens designs requires further investigation

Long-Term Impacts of Orthokeratology Treatment on Sub-Basal Nerve Plexus and Corneal Sensitivity Responses and Their Reversibility

Purpose: To examine the effects of one year of overnight orthokeratology (OK) treatment on the sub-basal nerve plexus (SBNP) and corneal sensitivity and to assess the reversibility of these effects one month after treatment interruption. Methods: Thirty-two subjects with low-moderate myopia underwent OK treatment for one year. Fifteen non-contact lens wearers served as controls. At the time points baseline, one year of treatment, and one month after removing the OK lenses, two tests were conducted: corneal sensitivity (Cochet-Bonnet esthesiometer) and SBNP imaging by in vivo confocal microscopy. Results: In participants wearing OK lenses, significant reductions over the year were produced in SBNP nerve density (P=0.001 and P=0.006) and number of nerves (P<0.001 and P=0.001) in the central and mid-peripheral cornea, respectively. Differences over the year were also detected in central objective tortuosity (P=0.002). After lens removal, baseline values of nerve density (P=0.024 and P=0.001) and number of nerves (P=0.021 and P<0.001) for the central and mid-peripheral cornea, respectively, were not recovered. At one month post-treatment, a difference was observed from one-year values in central corneal sensitivity (P=0.045) and mid-peripheral Langerhans cell density (P=0.033), and from baseline in mid-peripheral objective tortuosity (P=0.049). Direct correlation was detected at one year between nerve density and tortuosity both in the central (P<0.01; r=0.69) and mid-peripheral cornea (P<0.01; r=0.76). Conclusions: Long-term OK treatment led to reduced SBNP nerve density and this was directly correlated with corneal tortuosity. After one month of treatment interruption, nerve density was still reduced

Aprendizaje de procedimientos clínicos optométricos mediante vídeos demostrativos

El objetivo principal del proyecto ha sido crear en el campus virtual de la asignatura Optometría IV del Grado de Óptica y Optometría una plataforma de material docente virtual basado en presentaciones, vídeos de exploración y cuestionarios autoevaluativos. En ellos el alumno ha podido visualizar la ejecución por parte del profesor de los procedimientos que se estudian en la asignatura en pacientes pediátricos o con alteraciones de la visión binocular, de manera que el aprendizaje ha sido significativo

Anterior segment changes produced in response to long-term overnight orthokeratology

1.663 JCR (2013) Q3, 32/58 Ophtalmolog

Propiedades biomecánicas en la terapia refractiva corneal durante el periodo de adaptación y tras la interrupción del tratamiento: estudio piloto

Evaluar la influencia potencial y los cambios relacionados con el tratamiento de las propiedades biomecánicas corneales, medidas con el Analizador de Respuesta Ocular (ORA, Reichert, Depew, NY), durante los 15 días y 1 mes posteriores al comienzo e interrupción de la terapia refractiva corneal.No data (2013

Short and long term corneal biomechanical analysis after overnight orthokeratology

AIM: To investigate the short and long term corneal biomechanical changes after overnight orthokeratology (OK) and compare them with those occurring in subjects not wearing contact lenses. METHODS: Retrospective case control study enrolling 54 subjects that were divided into three groups 18 subjects each: control group (CG), short term (15 nights) OK (STOK) group, and long term (more than 1y of OK wear) OK (LTOK) group. Corneal biomechanics were characterized using the CorVis? ST system (Oculus), recording parameters such as time [first/second applanation time (AT1, AT2)], speed [velocity of corneal apex at the first/second applanation time (AV1, AV2)], and amplitude of deformation (AD1, AD2) in the first and second corneal flattening, corneal stiffness (SPA1), biomechanically corrected intraocular pressure (bIOP) and corneal (CBI) and tomographic biomechanical indices (TBI). RESULTS: Significantly lower AD1 and standard deviate on of Ambrosio’s relational average thickness related to the horizontal profile (ARTh) values were found in the OK groups compared to CG (P<0.05). Likewise, significantly higher values of CBI were found in STOK and LTOK groups compared to CG (P<0.01). No significant differences between groups were found in integrated radius index (P=0.24), strain stress index (P=0.22), tomographic biomechanical index (P=0.91) and corneal stiffness parameter (SPA1, P=0.97). Significant inverse correlations were found between corneal thickness and CBI in STOK (r= -0.90, P<0.01) and LTOK groups (r=-0.71, P<0.01). CONCLUSION: OK does not seem to alter significantly the corneal biomechanical properties, but special care should be taken when analyzing biomechanical parameters influenced by corneal thickness such as amplitude of deformation, ARTh or CBI, because they change significantly after treatment but mainly due to the reduction and pachymetric progression induced by the corneal molding secondary to OK treatment.Supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471