Repeatability assessment of biometric measurements with different refractive states and age using a swept-source biometer.

BACKGROUND: We aim to assess if refractive error or age may influence the repeatability of measurements using a swept-source biometer. METHODS: A total of 61 subjects were evaluated with IOLMaster 700 acquiring measurements of axial length (AL), central corneal thickness (CCT), white-to-white distance (WTW), anterior aqueous depth (AQD), lens thickness (LT), and keratometry (K) readings. Repeatability was evaluated classifying the sample according to the refractive state and age by the calculation of the within-subject standard deviation (Sw), coefficient of repeatability, and intraclass correlation coefficient. RESULTS: Very similar Sw was acquired among groups for AL, CCT, and WTW. Differences found for AQD, LT, keratometry and astigmatism among refractive and age groups were not clinically significant. Refractive groups obtained a Sw for AQD between 0.016 and 0.026, while for LT was between 0.023 and 0.029 mm. Besides, Sw showed values from 0.014 to 0.029 mm for keratometry. Age groups obtained a Sw of 0.025 and 0.016 mm for AQD, and 0.029 and 0.018 mm for LT, respectively. Sw was 0.019 vs 0.018 mm for K1, 0.014 vs 0.031 mm for K2. CONCLUSIONS: IOLMaster 700 showed good repeatability for biometric and keratometric parameters in eyes classified according to their refractive error or age.

Assessment of the association of matrix metalloproteinases with myopia, refractive error and ocular biometric measures in an Australian cohort.

Extracellular matrix proteins have been implicated in protein remodelling of the sclera in refractive error. The matrix metalloproteinases (MMPs) falling into the collagenase (MMP1, MMP8, MMP13), gelatinase (MMP2, MMP9) and stromelysin (MMP3, MMP10, MMP11) functional groups are particularly important. We wished to assess their association with myopia, refractive error and ocular biometric measures in an Australian cohort. A total of 543 unrelated individuals of Caucasian ethnicity were genotyped including 269 myopes (≤-1.0D) and 274 controls (>-1.0D). Tag single nucleotide polymorphisms (SNPs) (n = 53) were chosen to encompass these eight MMPs. Association tests were performed using linear and logistic regression analysis with age and gender as covariates. Spherical equivalent, myopia, axial length, anterior chamber depth and corneal curvature were the phenotypes of interest. Initial findings indicated that the best p values for each trait were 0.02 for myopia at rs2274755 (MMP9), 0.02 for SE at both rs3740938 (MMP8) and rs131451 (MMP11), 0.01 for axial length at rs11225395 (MMP8), 0.01 for anterior chamber depth at rs498186 (MMP1) and 0.02 at rs10488 (MMP1). However, following correction for multiple testing, none of these SNPs remained statistically significant. Our data suggests that the MMPs in the collagenase, gelatinase and stromelysin categories do not appear to be associated with myopia, refractive error or ocular biometric measures in this cohort.

Nonlinear optical macroscopic assessment of 3-D corneal collagen organization and axial biomechanics.

PURPOSE: To characterize and quantify the collagen fiber (lamellar) organization of human corneas in three dimensions by using nonlinear optical high-resolution macroscopy (NLO-HRMac) and to correlate these findings with mechanical data obtained by indentation testing of corneal flaps. METHODS: Twelve corneas from 10 donors were studied. Vibratome sections, 200 µm thick, from five donor eyes were cut along the vertical meridian from limbus to limbus (arc length, 12 mm). Backscattered second harmonic-generated (SHG) NLO signals from these sections were collected as a series of overlapping 3-D images, which were concatenated to form a single 3-D mosaic (pixel resolution: 0.44 µm lateral, 2 µm axial). Collagen fiber intertwining was quantified by determining branching point density as a function of stromal depth. Mechanical testing was performed on corneal flaps from seven additional eyes. Corneas were cut into three layers (anterior, middle, and posterior) using a femtosecond surgical laser system and underwent indentation testing to determine the elastic modulus for each layer. RESULTS: The 3-D reconstructions revealed complex collagen fiber branching patterns in the anterior cornea, with fibers extending from the anterior limiting lamina (ALL, Bowman's layer), intertwining with deeper fibers and reinserting back to the ALL, forming bow spring-like structures. Measured branching-point density was four times higher in the anterior third of the cornea than in the posterior third and decreased logarithmically with increasing distance from the ALL. Indentation testing showed an eightfold increase in elastic modulus in the anterior stroma. CONCLUSIONS: The axial gradient in lamellar intertwining appears to be associated with an axial gradient in the effective elastic modulus of the cornea, suggesting that collagen fiber intertwining and formation of bow spring-like structures provide structural support similar to cross-beams in bridges and large-scale structures. Future studies are necessary to determine the role of radial and axial structural-mechanical heterogeneity in controlling corneal shape and in the development of keratoconus, astigmatism, and other refractive errors.

[Comparative morphometric assessment between eyes with acute primary angle-closure glaucoma and contralateral eyes]. / Análise morfométrica comparativa entre olhos com glaucoma agudo primário e olhos contralaterais.

PURPOSE: To establish the profile of patients with acute primary angle-closure glaucoma (APACG) and to assess comparatively clinical and morphometric parameters between eyes with APACG and contralateral eyes (CLEs). METHODS: Prospective study including patients attended from September 2005 to March 2007. INCLUSION CRITERIA: diagnosis of APACG. EXCLUSION CRITERIA: presence of cataract (except for "glaukomflecken") that may cause low visual acuity or myopization, secondary glaucoma, previous APAGC or surgical procedure in the (CLE), no possibility to control the acute crisis of glaucoma clinically, plateau iris. The following were evaluated: incidence of APACG, age, gender, race, family history of glaucoma, corrected visual acuity (CVA) and uncorrected visual acuity (UVA), spherical equivalent (SE), cup/disc ratio (C/D), gonioscopy, keratometry (K), central corneal thickness (CCT), and echobiometric data [anterior central chamber depth (ACCD), axial length (AL), lens thickness (LT)] and relation between lens thickness and axial length (LT/AL). RESULTS: One thousand and three hundred and forty-three patients were examined from September 2005 to March 2006; 28 (2.1%) had the diagnosis of APACG. The incidence of the APACG was 20.8 cases per 1000 patients. The patients with APACG were manly white women with a negative familial history of glaucoma and with an average age of 59.6 years. When clinical aspects were compared between eyes with APACG and CLEs, statistical significance was observed: UVA (APACG: 0.27 +/- 0.32; CLE: 0.57 +/- 0.33, p=0.000); CVA (APACG: 0.53 +/- 0.44; CLE: 0.88 +/- 0.23, p=0.000); SE (APACG: +0.49 +/- 1.98; CLE: +1.21 +/- 2.03, p=0.007); C/D (APACG: 0.51 +/- 0.28; CLE: 0.42 +/- 0.20; p=0.031). Also, by gonioscopy, eyes with APACG demonstrated more frequently angle closure than CLEs. The eye of the crisis showed the following characteristics: average K of 45.21 +/- 1.96 D, average CCT of 534.46 +/- 34.15 mm, average ACCD of 2.43 +/- 0.28 mm, average AL of 21.68 +/- 0.96 mm, average LT 4.85 +/- 0.32 mm and average LT/AL of 2.24 +/- 0.16. The CLE presented average K of 44.92 +/- 1.86 D, average CCT of 533.18 +/- 31.41 microm, average ACCD of 2.51 +/- 0.29 mm, average AL of 21.82 +/- 0.92 mm, average LT 4.85 +/- 0.36 mm and average LT/AL of 2.23 +/- 0.18. There were statistically significant differences only in two parameters (K and ACCD) when affected and the CLE were compared. CONCLUSIONS: The incidence of the APACG was 20.8/1000. It was more frequent in white women, leu kodermics, without family history of glaucoma and with an age average of 59.6 years. The eyes with APACG showed, with statistical significance, worse visual acuity, higher C/D, lower hypermetropic SE, higher average K, and lower ACCD than CLEs.

Análise morfométrica comparativa entre olhos com glaucoma agudo primário e olhos contralaterais / Comparative morphometric assessment between eyes with acute primary angle-closure glaucoma and contralateral eyes

OBJETIVOS: Estabelecer o perfil dos pacientes com glaucoma agudo primário (GAP) e proceder a uma análise clínica e morfométrica comparativa entre o olho que sofreu a crise de GAP e o olho contralateral (OCL). Métodos: Estudo prospectivo. Foram avaliados pacientes no período de setembro de 2005 a março de 2007. Critério de inclusão: diagnóstico de GAP. Critérios de exclusão: catarata (exceto "glaukomflecken") à biomicroscopia que acarrete baixa acuidade visual ou miopização, glaucomas secundários, sinais de crise GAP prévio ou de procedimento cirúrgico anterior no OCL, impossibilidade de controle clínico do GAP, íris em platô. Foram avaliados: incidência do GAP, idade, sexo, raça, história familiar de glaucoma, acuidade visual com (AVCC) e sem correção (AVSC) na escala decimal, equivalente esférico (EE), escavação do disco óptico (E/D), gonioscopia, ceratometria (K), espessura central da córnea (ECC) e dados ecobiométricos [profundidade central da câmara anterior (PCCA), diâmetro axial ântero-posterior do olho (AXL), espessura do cristalino (CR)], e relação espessura do cristalino e diâmetro axial (CR/AXL). RESULTADOS: Foram admitidos 1346 pacientes no período de setembro de 2005 a março de 2007, 28 (2,1 por cento) tiveram o diagnóstico de GAP. A incidência de GAP no SGHSG (Serviço de Glaucoma do Hospital São Geraldo) foi de 20,8 por 1000 atendimentos. Os pacientes com GAP eram, na grande maioria, do sexo feminino, leucodérmicos, com história familiar negativa para glaucoma e média de idade de 59,6 anos. Na comparação entre olhos com GAP e os OCLs verificou-se diferença estatisticamente significativa nos seguintes parâmetros clínicos: AVSC (GAP:0,27 ± 0,32; OCL:0,57 ± 0,33, p=0,000); AVCC (GAP:0,53 ± 0,44; OCL:0,88 ± 0,23, p=0,000); EE (GAP: +0,49 ± 1,98; OCL: +1,21 ± 2,03, p=0,007); E/D (GAP: 0,51 ± 0,28; OCL: 0,42 ± 0,20; p=0,031). Além disso, à gonioscopia, os olhos com GAP apresentaram com maior freqüência os seios camerulares fechados...

PURPOSE: To establish the profile of patients with acute primary angle-closure glaucoma (APACG) and to assess comparatively clinical and morphometric parameters between eyes with APACG and contralateral eyes (CLEs). METHODS: Prospective study including patients attended from September 2005 to March 2007. Inclusion criteria: diagnosis of APACG. Exclusion criteria: presence of cataract (except for "glaukomflecken") that may cause low visual acuity or myopization, secondary glaucoma, previous APAGC or surgical procedure in the (CLE), no possibility to control the acute crisis of glaucoma clinically, plateau iris. The following were evaluated: incidence of APACG, age, gender, race, family history of glaucoma, corrected visual acuity (CVA) and uncorrected visual acuity (UVA), spherical equivalent (SE), cup/disc ratio (C/D), gonioscopy, keratometry (K), central corneal thickness (CCT), and echobiometric data [anterior central chamber depth (ACCD), axial length (AL), lens thickness (LT)] and relation between lens thickness and axial length (LT/AL). RESULTS: One thousand and three hundred and forty-three patients were examined from September 2005 to March 2006; 28 (2.1 percent) had the diagnosis of APACG. The incidence of the APACG was 20.8 cases per 1000 patients. The patients with APACG were manly white women with a negative familial history of glaucoma and with an average age of 59.6 years. When clinical aspects were compared between eyes with APACG and CLEs, statistical significance was observed: UVA (APACG: 0.27 ± 0.32; CLE: 0.57 ± 0.33, p=0.000); CVA (APACG: 0.53 ± 0.44; CLE: 0.88 ± 0.23, p=0.000); SE (APACG: +0.49 ± 1.98; CLE: +1.21 ± 2.03, p=0.007); C/D (APACG: 0.51 ± 0.28; CLE: 0.42 ± 0.20; p=0.031). Also, by gonioscopy, eyes with APACG demonstrated more frequently angle closure than CLEs. The eye of the crisis showed the following characteristics: average K of 45.21 ± 1.96 D, average CCT of 534.46 ± 34.15 mm, average ACCD of 2.43 ±...

Assessment of corneal wound healing by interactive topography.

INTRODUCTION: Constitutive properties of the cornea and wounds within the cornea have been measured previously by destructive methods in which a strip of cornea was removed, placed on an instrument, and stretched until broken. To assess corneal wound healing and the interaction of medication, incision patterns and other clinical issues, we present a simple, noninvasive test of corneal wound healing utilizing a videokeratoscope and Honan balloon. METHODS: A pre-test corneal topography was performed. The Honan balloon was placed on the eye at a pressure of 30mm mercury for 5 minutes. After removal of the balloon, additional corneal topographies were performed for comparison to the baseline topography. Study eyes were divided into six groups: 15 eyes in the normal group not involved in the Honan balloon test, 15 eyes formed a control group without previous ocular surgery, 15 eyes were within 3 months of radial keratotomy (RK), 15 eyes were more than 9 months after RK, 12 eyes had previous automated in situ keratomileusis (ALK), and 12 eyes had previous penetrating keratoplasty (PK). RESULTS: Average videokeratometric flattening was reported for all groups at intervals of 1, 2, and 3 minutes after removal of the Honan balloon. The normal group flattened by 0.04 +/- 0.10 D (range, +0.10 to -0.12 D) at 1 minute; 0.02 +/- 0.08 D (range, +0.10 to -0.10 D) at 2 minutes; and 0.02 +/- 0.06 D (range, +0.10 to -0.09 D) at 3 minutes. The control group flattened by -0.10 +/- 0.10 D (range, +0.30 to -0.30 D) at 1 minute; 0.01 +/- 0.12 D (range, +0.15 to -0.25 D) at 2 minutes; and 0.07 +/- 0.11 D (range, +0.14 to -0.18 D) at 3 minutes. The 3-month RK group flattened 0.95 +/- 0.23 D (range, 1.35 to 0.67 D) at 1 minute; 0.53 +/- 0.16 D (range, 0.71 to 0.39 D) at 2 minutes; and 0.40 +/- 0.15 D (range, 0.56 to 0.30 D) at 3 minutes. The 9-month RK group flattened 0.10 +/- 0.13 D (range, 0.23 to 0.02 D) at 1 minute; 0.10 +/- 0.12 D (range, 0.18 to -0.01 D) at 2 minutes; and 0.01 +/- 0.14 D (range 0.05 to 0.10 D) at 3 minutes. The ALK group flattened 0.65 +/- 0.42 D (range 0.98 to 0.38 D) at 1 minute; 0.27 +/- 0.19 D (range 0.39 to 0.10 D) at 2 minutes; and 0.21 +/- 0.17 D (range, 0.29 to 0.09 D) at 3 minutes. The PK group flattened 1.30 +/- 0.60 D (range, 1.75 to 0.90 D) at 1 minute; 1.18 +/- 0.43 D (range, 1.51 to 0.98 D) at 2 minutes; and 0.41 +/- 0.57 D (range, 0.88 to 0.30 D) at 3 minutes. CONCLUSIONS: We have established normal corneal wound healing curves from preliminary data utilizing Buzard interactive topography on normal control eyes and after radial keratotomy, automated lamellar keratoplasty, and penetrating keratoplasty. Deviation from these normal curves indicates either excessive or inadequate wound healing.

Methodologic differences and measurement of cup-disc ratio: an epidemiologic assessment.

A retrospective analysis was undertaken to estimate the effect on measurements of cup-disc ratio (CDR) that result from overall differences among examination methods used by experienced investigators. The findings suggest large inter-observer differences, that is, large differences in measurement attributable to differences in definitions and methods between one observer and another. Extreme caution is indicated before attaching wide clinical or investigative importance to a specific value of CDR. A value of CDR regarded as the dividing line between normalcy and suspicion by one observer may be a highly inappropriate cutoff for another observer. Similarly, if different observers record measurements on the same patient, it may be impossible to determine whether the cup of an individual patient changes with time. Interobserver differences also can cast doubt on conclusions drawn from the comparison of data collected by different investigators. There is a need for standardization of definitions and methods in such clinical or research situations.