Article

Repeatability and reproducibility of pachymetric mapping with Visante anterior segment-optical coherence tomography.

Hong Kong Eye Hospital, Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Peoples Republic of China.
Investigative Ophthalmology &amp Visual Science (Impact Factor: 3.44). 01/2008; 48(12):5499-504. DOI: 10.1167/iovs.07-0591
Source: PubMed

ABSTRACT To determine the repeatability and reproducibility of central and peripheral corneal pachymetry mapping with anterior segment-optical coherence tomography (AS-OCT).
An observational cross-sectional study involving two groups: 27 healthy eyes and 20 eyes with keratoconus. Each subject underwent scanning sessions with AS-OCT to determine intraobserver repeatability, interobserver reproducibility, and additionally for healthy eyes, intersession reproducibility for different regions of the cornea up to a 10-mm diameter. Main outcome measures were reproducibility and repeatability coefficients, intraclass correlation coefficients, and coefficients of variation of the average central (0-2 mm), pericentral (2-5 mm), transitional (5-7 mm), and peripheral (7-10 mm) corneal thicknesses generated by the Visante AS-OCT (Carl Zeiss Meditec, Inc., Dublin, CA) pachymetric mapping protocol.
The coefficients of repeatability were less than 2% in healthy subjects and less than 3% in patients with keratoconus. The reproducibility coefficients were less than 2% and 4% in healthy subjects and patients with keratoconus, respectively. There was no significant difference between scans obtained by different observers or during different visits. The intraclass correlation coefficients were greater than 0.99 and 0.97 in healthy subjects and patients with keratoconus, respectively.
With the pachymetric mapping protocol of Visante AS-OCT, these results suggest that central and peripheral corneal thickness measurements in healthy subjects and in eyes with keratoconus are repeatable and reproducible.

0 Bookmarks
 · 
83 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the characteristics of the graft-host interface after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography (AS-OCT). Forty-nine eyes of 49 patients with three different underlying diseases (corneal scar, 22 eyes; bullous keratopathy, 14 eyes; keratoconus, 13 eyes) who underwent PKP were retrospectively reviewed. AS-OCT was performed in all patients and wound profiles of the graft-host junctions were classified into well-apposed junction, gap, step, and protrusion. The correlations between clinical characteristics and wound profiles from the AS-OCT were analyzed. A total of 392 graft-host junctions from 49 eyes were analyzed. Among them, 155 sections (39.5 %) had well-apposed junctions and 237 sections (60.5 %) had malapposed junctions. The most frequent type of malapposition was protrusion (117 sections, 39.9 %). When categorizing the eyes according to the most frequent alignment type among the 8 cross-sections, the alignment pattern showed significant differences between the preoperative diagnosis groups (P = 0.04). Spherical equivalent (P = 0.04) and keratometric astigmatism (P < 0.01) showed significant differences between the alignment groups. Graft-host thickness disparities showed significant correlations with keratometric astigmatism (r = 0.56, P < 0.01) and degree of graft oversize (r = 0.29, P = 0.04). The alignment pattern of wound interface after PKP differed according to the clinical diagnosis before surgery and was significantly associated with spherical equivalent and keratometric astigmatism.
    Japanese Journal of Ophthalmology 02/2014; · 1.27 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the relationship between different ocular and corneal biomechanical parameters in emmetropic and ametropic healthy white children. This study included 293 eyes of 293 healthy Spanish children (135 boys and 158 girls), ranging in age from 6 to 17 years. Subjects were divided according to the refractive error: control (emmetropia, 99 children), myopia (100 children), and hyperopia (94 children) groups. In all cases, corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated with the Ocular Response Analyzer system. Axial length (AL) and mean corneal power were also measured by partial coherence interferometry (IOLMaster), and central corneal thickness (CCT) and anterior chamber depth were measured by anterior segment optical coherence tomography (Visante). Mean (±SD) CH and CRF were 12.12 (±1.71) and 12.30 (±1.89) mm Hg, respectively. Mean (±SD) CCT was 542.68 (±37.20) μm and mean (±SD) spherical equivalent was +0.14 (±3.41) diopters. A positive correlation was found between CH and CRF (p < 0.001), and both correlated as well with CCT (p < 0.0001). Corneal resistance factor was found to decrease with increasing age (p = 0.01). Lower levels of CH were associated with longer AL and more myopia (p < 0.001 and p = 0.001, respectively). Higher values of CH were associated with increasing hyperopia. Significant differences in CH were found between emmetropic and myopic groups (p < 0.001) and between myopic and hyperopic groups (p = 0.011). There were also significant differences in CRF between emmetropic and myopic groups (p = 0.02). Multiple linear regression analysis showed that lower CH and CRF significantly associated with thinner CCT, longer AL, and flatter corneal curvature. The Ocular Response Analyzer corneal biomechanical properties seem to be compromised in myopia from an early age, especially in high myopia.
    Optometry and vision science: official publication of the American Academy of Optometry 04/2014; · 1.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Biomicroscopy is generally used, sometimes in conjunction with photography or ultrasound pachymetry, to monitor conditions involving stromal keratitis and edema. Spectral-domain optical coherence tomography (SD-OCT), a technology typically used to examine the posterior segment, may be useful in monitoring the therapeutic interventions for conditions involving corneal edema such as disciform keratitis. Two cases of disciform keratitis were followed to resolution using SD-OCT with anterior segment imaging software (Cirrus 4000; Carl Zeiss Meditec, Dublin, CA) to quantify decreasing edema throughout treatment. The thickest area of the cornea was located and measured across time using SD-OCT until resolution was achieved. Throughout each case, SD-OCT allowed precise localization of microcystic edema and keratic precipitates as well as the objective measurement of therapeutic interventions resulting in reduced edema and thickness. The use of SD-OCT allows objective measurements of corneal thickness and presents an additional method for following stromal keratitis with greater accuracy than can be appreciated using biomicroscopy alone.
    Optometry and vision science: official publication of the American Academy of Optometry 03/2014; · 1.53 Impact Factor

Full-text

View
0 Downloads
Available from