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 co...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 1 y of OK wear) OK(LTOK) group. Corneal biomechanics were characterized using the Cor Vis? 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(b IOP) 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 stif fness 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.展开更多
AIMTo present the results of same-day topography-guided photorefractive keratectomy (TG-PRK) and corneal collagen crosslinking (CXL) after previous intrastromal corneal ring segment (ISCR) implantation for keratoconus.
AIM：To compare visual efficiency,specifically accommodation,vergence,and oculomotor functions among athletes and non-athletes.METHODS：A cross-sectional study on sports vision screening was used to evaluate the visua...AIM：To compare visual efficiency,specifically accommodation,vergence,and oculomotor functions among athletes and non-athletes.METHODS：A cross-sectional study on sports vision screening was used to evaluate the visual skills of 214elementary students（107 athletes,107 non-athletes）,aged between 13 and 16y.The visual screening assessed visual parameters such as ocular motor alignment,accommodation,and vergence functions.RESULTS：Mean visual parameters were compared between age-group matched athletes（mean age14.82±0.98y）and non-athletes（mean age 15.00±1.04y）.The refractive errors of all participants were corrected to maximal attainable best corrected visual acuity of log MAR0.0.Accommodation function assessment evaluated amplitude of accommodation and accommodation facility.Vergence functions measured the near point of convergence,vergence facility,and distance fusional vergence at break and recovery point.Ocular motor alignment was not statistically significant between both groups.Athletes had a statistically significant amplitude of accommodation for both the right eye（t=2.30,P=0.02）and the left eye（t=1.99,P=0.05）.Conversely,non-athletes had better accommodation facility（t=-2.54,P=0.01）and nearpoint of convergence（t=4.39,P〈0.001）when compared to athletes.Vergence facility was found to be better among athletes（t=2.47,P=0.01）.Nevertheless,non-athletes were significantly better for both distance negative and positive fusional vergence.CONCLUSION：Although the findings are still inconclusive as to whether athletes had superior visual skills as compared to non-athletes,it remains important to identify and elucidate the key visual skills needed by athletes in order for them to achieve higher performance in their sports.展开更多
基金Supported by the Ministry of EconomyIndustry and Competitiveness of Spain within the program Ramón y Cajal,RYC-2016-20471。
文摘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 1 y of OK wear) OK(LTOK) group. Corneal biomechanics were characterized using the Cor Vis? 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(b IOP) 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 stif fness 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.
基金the Research Centre,College of Applied Medical Sciences and the Deanship of Scientific Research at King Saud University for funding this research
文摘AIMTo present the results of same-day topography-guided photorefractive keratectomy (TG-PRK) and corneal collagen crosslinking (CXL) after previous intrastromal corneal ring segment (ISCR) implantation for keratoconus.
基金Supported by the Ministry of Higher Education Malaysia Sports Grant[No.KPT.N.660-7 Jld 7(3)]UKM Research Code NN-2013-069
文摘AIM：To compare visual efficiency,specifically accommodation,vergence,and oculomotor functions among athletes and non-athletes.METHODS：A cross-sectional study on sports vision screening was used to evaluate the visual skills of 214elementary students（107 athletes,107 non-athletes）,aged between 13 and 16y.The visual screening assessed visual parameters such as ocular motor alignment,accommodation,and vergence functions.RESULTS：Mean visual parameters were compared between age-group matched athletes（mean age14.82±0.98y）and non-athletes（mean age 15.00±1.04y）.The refractive errors of all participants were corrected to maximal attainable best corrected visual acuity of log MAR0.0.Accommodation function assessment evaluated amplitude of accommodation and accommodation facility.Vergence functions measured the near point of convergence,vergence facility,and distance fusional vergence at break and recovery point.Ocular motor alignment was not statistically significant between both groups.Athletes had a statistically significant amplitude of accommodation for both the right eye（t=2.30,P=0.02）and the left eye（t=1.99,P=0.05）.Conversely,non-athletes had better accommodation facility（t=-2.54,P=0.01）and nearpoint of convergence（t=4.39,P〈0.001）when compared to athletes.Vergence facility was found to be better among athletes（t=2.47,P=0.01）.Nevertheless,non-athletes were significantly better for both distance negative and positive fusional vergence.CONCLUSION：Although the findings are still inconclusive as to whether athletes had superior visual skills as compared to non-athletes,it remains important to identify and elucidate the key visual skills needed by athletes in order for them to achieve higher performance in their sports.
