Optical quality and intraocular scattering in a healthy young population

Abstract

Background:We objectively assessed the optical quality and intraocular scattering by means of parameters provided by a clinical double-pass system in healthy young subjects and thereby we obtained new reference data for clinical diagnosis. We calculated normal values of neural contrast sensitivity function (nCSF) from the measured modulation transfer function (MTF) and the contrast sensitivity function (CSF). Methods: Eligible subjects were healthy adults aged from 18 to 30 years with a logMAR visual acuity (VA) of 0.0 or better and normal values of CSF. Optical quality measurements for a 4.0 mm pupil were performed using the Optical Quality Analysis System (OQAS) based on the double-pass technique. The following parameters were analysed: the modulation transfer function cutoff frequency (MTF cutoff), the Strehl 2D ratio, the OQAS values (OV) at 100, 20 and nine per cent contrasts and the objective scatter index (OSI). Results: A total of 178 volunteers responded to the call, of whom 181 eyes were finally part of the study taking into account the criteria for inclusion. The values for the optical quality parameters were: 44.54 Ϯ 7.14 cpd (MTFcutoff), 0.27 Ϯ 0.06 (Strehl 2D ratio), 1.48 Ϯ 0.24 (OV100%), 1.58 Ϯ 0.32 (OV20%), 1.64 Ϯ 0.39 (OV9%), and 0.38 Ϯ 0.19 (OSI). The nCSF calculated was 1.76 Ϯ 0.21 (3 cpd), 2.13 Ϯ 0.23 (6 cpd), 2.01 Ϯ 0.28 (12 cpd) and 1.86 Ϯ 0.33 (18 cpd). Conclusion:The normal values provided can be a useful tool for discriminating healthy eyes from early abnormal ones in which the optical quality or sensory function is impaired.

Optical quality after myopic photorefractive keratectomy and laser in situ keratomileusis: Comparison using a double-pass system

“…Normal values for these parameters in a healthy young population, a post-refractive surgery group, and a cataract group have been reported. [47][48][49] The MTF cutoff corresponds to a 0.01 MTF value in the double-pass instrument because there is background noise in the MTF profile from the real recorded double-pass image. This parameter is directly related to the patient's visual acuity, although it is not affected by retinal and neural factors.…”

Double-pass technique and compensation-comparison method in eyes with cataract

“…A combined analysis of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 [19][20][21][22] . It computes an objective scatter index (OSI) 23 , which is a dimensionless parameter based on the relative intensity divided by 10 between the central area within 1 minute of arc and a peripheral ring between 12 and 20 minutes of arc of the DP image of the eye.…”

High-gain visual feedback exacerbates ankle movement variability in children

“…For example, the visual system of children is immature compared with that of adults (Liu et al 2014). This is demonstrated by Liu et al (2014) as a lower contrast sensitivity function in children, which is considered to be the most fundamental assessment of the visual system (Martinez-Roda et al 2011;Michael et al 2011). In addition, the deficient visuomotor integration observed in preadolescent children in this study and the study by Deutsch and Newell (2002) may be the consequence of immature cortical activation in specific areas of the brain.…”