| ObjectiveTo compare the axial length, spherical equivalent, retinal nerve fiber layer (RNFL) and the choroidal thickness in young adult with low, moderate, high and extremely high myopia.MethodsA total of123eyes of62individuals with myopia were classified into4groups. The group was stratified according to refractive error into low myopia (-0.50D to-2.75D), moderate myopia (-3.0D to-5.75D), high myopia (.-6.0D to-9.75D), extremely high myopia (≥-10.0D). All subjects underwent a thorough ocular examination; including Intraocular pressure (IOP), autorefractometer, comprehensive refractometer, best-corrected visual acuity (BCVA), axial length measurement, RNFL thickness and choroidal thickness. RNFL thickness and choroidal thickness were imaged by positioning the Spectral-Domain Optical Coherence Tomography (SD-OCT) device (Heidelberg Germany). RNFL scan protocol using circμmpapillary scans with a preset diameter of3.46mm centered around the optic nerve head, the peripapillary RNFL thickness was divided into four quadrants defined as superior (46to135degrees), nasal (136to225degrees), inferior (226to315degrees) and temporal (316to45 degrees). Then we characterized the RNFL thickness in young adult, Compare RNFL thickness with low, moderate, high, and extremely high myopia.and to examine RNFL thickness and correlation with refraction and axial length. Choroidal thickness measurements were made of the subfoveal choroid and at1.5mm intervals from the fovea to3mm nasal,3mm temporal,3mm superior, and3mm inferior from the center of the fovea (9ETDRS sectors). The values of the measurements were compared by each observer and then averaged for analysis.characterized the choroidal thickness in young adult. Compare choroidal thickness with low, moderate, high, and extremely high myopia and to examine choroidal thickness correlation with refraction and axial length.ResultsThe study population consisted of123eyes of62individual, the mean age was21.66±0.78(range,20-23)years,the mean refractive error was-5.05±3.42(range,-0.5-13.25) diopters, the mean axial length was25.56±1.41(range,23.09～29.20)mm. The mean IOP was16.16±2.47mmHg. The mean RNFL thickness was97.62±26.31μm at temporal,47.63±18.65μm at nasal,116.99±21.34μm at superior, and117.50±20.45μm at inferior. The mean RNFL thickness was thicker inferiorly and superiorly, there was no statistically significant between inferior and superior (p>0.05).Then followed by the temporal, and the nasal was the thinnest (p=0.000). Superior, inferior, nasal and temporal RNFL thicknesses were significant difference compared with low, moderate, high and extremely high myopia groups (p=0.000). The RNFL thickness in inferior, superior and nasal quadrant is thinner and thinner with an increase of myopia degree (p<0.005). The RNFL thickness in temporal quadrant is thicker and thicker with an increase of myopia degree except extremely high myopia group. The Superior, inferior, nasal RNFL thickness was significant correlated with refraction error, axial length and choroidal thickness (p<0.005). Temporal RNFL thicknesses was not significant correlated with refraction error, axial length (p>0.05). Mean macular choroidal thicknesses were252.55±146.15μm at fovea,246.87±60.79μm at temporally,167.05±55.40μm at nasally,256.78±58.51μm at superiorly and241.57±63.19μm at inferiorly. The choroidal was the thickest at superior and subfoveal, and the nasal area was thinnest (p=0.000). Choroidal thickness at each sector was significant difference compared with low, moderate, high and extremely high myopia groups (p<0.01). The choroid in highly myopia eyes was thinner than that in low myopia eyes. The mean choroidal thickness at each sector showed a significant correlation with refraction error, axial length and superior, inferior, nasal RNFL thickness (p<0.05).Conclusions:RNFL thickness and choroidal thickness are significantly associated with refraction error and axial length. |
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