Abstract
PurposeTo determine normal macular thickness and its variation by age and gender in healthy eyes using spectral-domain optical coherence tomography (SD-OCT).MethodsIn this cross-sectional analysis, two hundred and twenty eyes of 220 healthy subjects underwent raster scanning using Topcon SD-OCT system, at the Department of Ophthalmology, Dow University of Health Sciences and Civil Hospital Karachi, Pakistan. Macular thickness from all 9 regions of the ETDRS map was documented for each subject. Variations in macular thickness measurements by age and gender were determined.ResultsThe 220 subjects had a mean age of 45.3 years (16–80 years). Using the ETDRS map, foveal thickness for all subjects was measured to be 229±20.46 µm. Mean macular thickness for all subjects was 262.8±13.34 µm. Male gender was associated with greater foveal (p<0.0001) and mean macular (p<0.0001) thickness compared to females. There was no association of mean macular thickness (r2 = 0.01; p>0.05) and foveal thickness (r2 = 0.00004; p>0.05) with age.ConclusionWe have provided normative data for macular thickness using Topcon SD-OCT system. Our results are comparable to some and vary from other reports using the similar OCT system. Our results suggest that male gender is associated with greater macular thickness, while macular thickness has no association with age in healthy eyes. This is the first normative data for macular thickness from Pakistan; benchmark for diagnosing and monitoring macular pathologies. The values obtained in this study may be useful for comparison with other populations, other SD-OCT systems and future imaging technologies.
Highlights
An increase in retinal thickness due to fluid accumulation is found in many ocular disorders such as diabetic retinopathy, age-related macular degeneration, central serous chorio-retinopathy (CSCR) and retinal vein occlusion
Of the commercially available optical coherence tomography (OCT) systems, a documented variability in macular thickness measurements has been reported [19,20,21,22,23], While Stratus OCT selects the inner segment/outer segment (IS/OS) junction as the outer retinal boundary for macular thickness measurements [5,19,20,21,22,24,25], spectral domain OCT systems select retinal pigment epithelium (RPE) as the outer retinal boundary for thickness measurements, leading to an increase in macular thickness reported with these systems, when compared to the TDOCT systems, while a slight variability amongst the different spectral-domain optical coherence tomography (SD-OCT) systems based on the various scanning protocols and differences in the segmentation algorithms [5,19,20,21,22,23,25]
We used the Topcon SD-OCT, which uses the inner border of RPE as the outer retinal boundary for macular thickness measurements
Summary
Macular edema is a common cause of visual impairment, and the degree of macular thickening is significantly correlated with visual acuity [1]. Traditional investigations for evaluating macular edema/thickening, such as fundus photography, slit lamp biomicroscopy and fluorescein angiography (FA), can provide only qualitative information, which is relatively insensitive to subtle changes in macular thickness [3]. OCT uses low coherence interferometry of light to examine the retina in vivo [4]. With progression of this technology, a true, non-contact, non-invasive ‘‘optical biopsy’’ of the posterior segment of the eye is achievable. It has enabled clinicians to appreciate refined details of the posterior segment of the eye on a micron scale, and to reliably detect and quantify subtle changes in macular thickness, making objective monitoring of disease progression and efficacy of different therapeutic modalities in various ocular diseases plausible [5,6,7]
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