Congenital and developmental cataract: axial length and keratometry study in Brazilian children / Catarata congênita e do desenvolvimento: estudo do comprimento axial e da ceratometria em crianças brasileiras

ABSTRACT Purpose: To evaluate the ocular axial length (AL) and keratometry (K) in Brazilian children with congenital/developmental cataract, assess the differences and evolution of AL and K according to age, and establish functional models of AL and K as function of age. Methods: Children with congenital/developmental cataract aged 1.5 months old to 8 years old and no other ocular diseases were included. All eyes with unilateral cataract, the left eyes from children with bilateral cataracts, and healthy eyes from children with unilateral cataract were analyzed. After the administration of anesthesia, K was measured with a portable automatic keratometer, and AL was measured with a contact biometer. Cataract surgery was performed immediately after the measurements were taken. The data were statistically analyzed, and a linear regression with an age logarithm was used to model the relationship. Results: Forty-four eyes with cataract were included in this analysis, comprising 15 eyes with unilateral cataract and 29 left eyes from children with bilateral cataracts. The mean age was 27.3 months with a mean AL of 20.63 ± 2.11 mm and a mean K of 44.94 ± 2.44 D. The K value was significantly steeper and the AL value was significantly shorter in younger children (P< 0.001). No significant differences were found neither between eyes with unilateral and bilateral cataracts nor between eyes with unilateral cataract and their corresponding healthy eyes (P >0.05). Conclusion: The values of K and AL significantly change with age, especially during the first 6 months of life. A linear functional relationship between K and AL with the logarithm of age and between K and AL was established.

RESUMO Objetivo: Avaliar o comprimento axial (AL) e a ceratometria (K) de olhos de crianças brasileiras com catarata congênita/desenvolvimento, analisar diferenças e evoluções de acordo com a idade e estabelecer modelos funcionais de comprimento axial e ceratometria em função da idade e entre eles. Métodos: Crianças com catarata congênita/desenvolvimento com idade de 1,5 meses a 8 anos de idade e sem outras doenças oculares foram incluídas. Todos os olhos com catarata unilateral, o olho esquerdo de crianças com catarata bilateral e o olho sadio de crianças com catarata unilateral foram analisados. Após a administração de anestesia, a ceratometria foi obtida com um ceratômetro automático portátil e o comprimento axial medido com um biômetro de contato. Em seguida, a cirurgia de catarata foi realizada. Os dados foram analisados estatisticamente, a regressão linear com o logaritmo da idade foi utilizado para modelar os relacionamentos. Resultados: Todos os olhos com catarata unilateral (n=15) e um olho selecionados aleatoriamente a partir dos casos bilaterais (n=29) foram incluídos na análise (total= 44 olhos). A idade média foi de 27,3 meses, as médias do comprimento axial e da ceratometria foram respectivamente 20,63 ± 2,11 mm e 44,94 ± 2,44 dioptrias. A ceratometria foi significativamente mais curvo e comprimento axial significantemente mais curto em crianças mais jovens (P<0,001). Não foram encontradas diferenças significativas na comparação entre os olhos com cataratas unilaterais e bilaterais e comparando os olhos com catarata unilateral a correspondentes olhos saudáveis (P>0,05). Conclusão: Os valores de ceratometria e comprimento axial mudam significativamente com a idade, principalmente nos primeiros seis meses de vida. Foi estabelecida uma relação funcional linear entre comprimento axial e ceratometria com o logaritmo da idade e entre ceratometria e comprimento axial.

Repeatability of Ophtha TOP in measuring corneal parameters and its agreement with Pentacam / 中华实验眼科杂志

Background Accurate measurement of corneal refractive parameters plays an important role in the diagnosis of eye diseases,design of refractive surgery and calculation of intraocular lens (IOL) power.Ophtha TOP is a new IOL calculator,so it is necessary to evaluate the repeatability and accuracy of Ophtha TOP in measuring corneal refractive parameters.Objective This study was to evaluate the repeatability of Ophtha TOP in measuring corneal refractive status in normal eyes and determine the agreement of the measuring outcomes between Ophtha TOP and Pentacam in pre-surgery cataract eyes.Methods A reliability evaluation method of diagnosis test was performed from September 2013 to October 2014.Sixty eyes of healthy volunteers aged (30.83 ±8.66) years old were examined in Tianjin Eye Hospital with Ophtha TOP for more than 5 times to evaluate the stability in measuring corneal refractive parameters.Corneal refractive parameters were measured by both Ophtha TOP and Pentacam for more than twice in 30 pre-surgery cataract eyes to assess the agreement with Pentacam.Keratometry and astigmatism parameters were recorded,including the flattest meridian (Kf),steepest meridian (Ks),mean keratometry (Km) and the astigmatism at J0 and J45.Intra-class correlation coefficients (ICC),repeatability (2.77Sw) and coefficient of variation (CoVs) were used to assess the stability of Ophtha TOP,and Bland-Altman graphs were adopted to value the consistency of measuring outcomes between Ophtha TOP and Pentacam.This study complied with Helsinki declaration,and written informed consent was obtained from each patient prior to any medical examination.Results The ICC of Ks,Kf,Km,J0 and J45 by Ophtha TOP were all ≥0.90,and 2.77Sw were all ≤0.36,The CoVs of Kf,Ks,Km by Ophtha TOP were all ≤0.30.The measuring values of Kf,Ks and Km were significantly higher in the Ophtha TOP than those in the Pentacam,with the mean differences (0.18±0.28) D,(0.24±0.29) D and (0.21± 0.26) D,respectively(t =3.48,4.50,4.49,all at P=0.00).The mean difference of the J0 was (0.07±0.21) D and that of the J45 was (-0.02±0.18)D between Ophtha TOP and Pentacam,showing insignificant differences between them (both at P＞0.05).Bland-Altman graphs revealed that the 95％ limit of agreement (LoA) of Kf,Ks and Km between the two methods was-0.37 D to 0.73 D,-0.33 D to 0.81 D and-0.30 D to 0.72 D,respectively,and that of J0 and J45 was-0.34 D to 0.48 D and-0.37 D to 0.33 D,respectively.Conclusions Ophtha TOP shows an excellent repeatability.Compared with Pentacam,Ophtha TOP presents a good consistence for measurement of the corneal astigmatism and moderate consistence for corneal curvature.

Optimization of optical performance of biconvex Toric intraocular lens using a customized vision model / 中华实验眼科杂志

Background The optic quality of Toric intraocular lens (IOL)-implanted eye is affected by the residual astigmatism and individual difference of corneal spherical aberration and different magnification from steep and flat axis refraction.Whether correcting Toric IOL spherical aberration can effectively improve the image quality of individual patient is a question to be studied.Objective This study attempted to collect eye parameters of cataract patients to reconstruct the customized vision model by using Zemax optical software,and to evaluate the image performance with different Toric IOL spherical aberration.Methods A prospective study was performed.Forty-five eyes of 45 cataract patients were included in Second Hospital of Hebei Medical University from August 2012 to October 2013.Several relevant parameters were measured by Pentacam,including anterior and posterior surface height of cornea,corneal thickness,curvature radius of flat and steep meridians of anterior surface astigmatism,refractive diopter and curvature radius of posterior surface.The astigmatism of anterior and posterior corneal surface was described by Matlab 4.5 software.Corneal astigmatism model were set as aspheric state,and the effective position of Toric IOL was calculated using Holladay Ⅰ formula.Customized individual model eyes were constructed by Zemax software.The contrast sensitivity function (CSF) of different spherical Toric IOLs at different spatial frequencies were calculated and compared between 300 Td light environment with 3 mm pupil diameter (photopia light) and 0.3-1.0 Td light environment with 5 mm pupil diameter (mesopia light).This study was approved by Second Hospital of Hebei Medical University ethics committee,all the patients signed the informed consent.Results The mean astigmatism power was (1.51 ± 0.36) D and (1.49 ± 0.37) D,and the mean astigmatism meridian was (101.5 ± 59.8) ° and (101.9±58.5) ° in the model eyes and cataract eyes,respectively,without significant differences between them (t=0.886,0.652;both at P＞0.05).Bland-Altman test showed a good agreement in astigmatism power and astigmatism meridian between model eyes and cataract eyes.The LogCSF values at 1.5,3.0,6.0,12.0 and 18.0 c/d spatial frequencies were significantly higher in the aspherical Toric IOL model eyes than those in the spherical Toric IOL model eyes,and the LogCSF values at various spatial frequencies were significantly higher in the Toric IOLs with spherical aberrations of-0.13 μm and-0.26 μm than those in the zero spherical aberrations in both photopia light and mesopia light (all at P＜0.05).Conclusions A precise corneal astigmatism model based on cornea high data of cataract eyes was successfully constructed through special formulas with Zemax software.Aspherical Toric IOL can compensate for spherical aberration of cornea and enhance the optic quality in individual model eye.

Comparison of central corneal thickness measurements using optical low-coherence reflectometry, Fourier domain optical coherence tomography, and Scheimpflug camera / Comparação entre medidas de espessura central da córnea com reflectometria óptica de baixa coerência, tomografia de coerência óptica de domínio Fourier, e câmera Scheimpflug

Purpose: To compare the results of central corneal thickness (CCT) measurements obtained using optical low-coherence reflectometry (OLCR), Fourier domain optical coherence tomography (FD-OCT), and a Scheimpflug camera (SC), combined with Placido corneal topography. Methods: A total of 25 healthy subjects were enrolled in the present study, and one eye of each subject was included. A detailed ophthalmic examination was performed in all cases following CCT measurements with OLCR, FD-OCT, and SC. The results were compared using an ANOVA test. Bland-Altman analysis was used to demonstrate agreement between methods. Intra-examiner repeatability was assessed by using intraclass correlation coefficients (ICCs). Results: Statistically significant differences were observed between the results of the CCT measurements obtained using the three different devices (p=0.009). Significant correlations were found between OLCR and FD-OCT (r=0.97; p<0.0001), FD-OCT and SC (r=0.91; p<0.0001), and OLCR and SC (r=0.95; p<0.0001). The 95% limits of agreement (LOA) obtained from Bland-Altman plots were from -7.2 μm to 28.7 μm for OLCR versus FD-OCT, from -19.2 μm to 30.4 μm for OLCR versus SC, and from -42.6 to 32.3 μm for FD-OCT versus SC. Intra-examiner repeatability was excellent for each method, with ICCs >0.98. Conclusion: Although the results of CCT measurements obtained from these three devices were highly correlated with one another and the mean differences between instruments were comparable with the reported diurnal CCT fluctuation, the measurements are not directly interchangeable in clinical practice because of the wide LOA values. .

Objetivo: Comparar os resultados de medições de espessura corneana central (CCT ) obtidos com reflectometria óptica de baixa coerência (OLCR), tomografia de coerência óptica de domínio Fourier (FD-OCT ), e uma câmera Scheimpflug (SC), combinada com topografia corneana de placido. Métodos: Um olho de cada de 25 indivíduos saudáveis foram incluídos neste estudo. Um exame oftalmológico detalhado foi realizado em todos os casos após as medidas de CCT com OLCR, FD-OCT, e SC. Os resultados foram comparados por meio do teste ANOVA. Análise de Bland-Altman foi utilizada para demonstrar concordância entre os métodos. A repetibilidade intra-examinador foi avaliada por meio de coeficientes de correlação intraclasse (ICCs). Resultados: Foram observadas diferenças estatisticamente significativas entre os resultados das medidas de CCT obtidas a partir de três dispositivos diferentes (p=0,009). Foram encontradas correlações significativas entre OLCR e FD-OCT (r=0,97, p<0,0001), FD-OCT e SC (r=0,91, p<0,0001), e OLCR e SC (r=0,95; p<0,0001). Os limites de 95% de confiança (LOA) obtidos a partir de gráficos de Bland-Altman foram de -7,2 a 28,7 μm para OLCR contra FD-OCT, de -19,2 a 30,4 μm para OLCR contra SC, e de -42,6 a 32,3 μm para FD-OCT contra SC. A repetibilidade intra-examinador foi excelente para cada método com ICCs>0,98. Conclusões: Apesar de os resultados das medições CCT obtidos a partir destes três dispositivos terem sido altamente correlacionados entre si e as diferenças médias entre os instrumentos serem comparáveis à flutuação relatado da CCT diurna, as medições não são diretamente intercambiáveis na prática clínica em razão da largura dos valores limites de confiança. .