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Julie-Anne Little, Patrick S Richardson, Kathryn J Saunders, Aman-Deep Singh Mahil; Quantifying crystalline lens opacities in Down syndrome with Anterior Segment OCT. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5649. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Down syndrome (DS) is frequently associated with cataract (prevalence 5-50%). Few studies have described congenital cerulean blue-dot cataracts, while others report cataracts similar to those seen in the ageing eye. It has also been proposed that supra-nuclear cataracts in DS are indicative of beta-amyloid aggregation. However, there remains scant information about morphology and frequency of cataract in non-clinical DS populations. This study employed anterior segment OCT and slit-lamp photography to image the crystalline lens in DS, compared with developmentally typical controls.
Assessment included case history, slit-lamp examination, intra-ocular pressure and visual acuity. Lens images were obtained by OCT (Zeiss Visante AS-OCT) after pupil dilation (Tropicamide 1%). Raw OCT data were processed in Matlab, and nucleus clarity and opacities analysed by calculating pixel intensity and area ratios (PIR and PAR). Participants were 28 individuals with DS (mean age 24.1±14.3years; range 6-55years; 17 male) and 36 controls (mean age 54.0±3.4years; range 50-60years; 11 male) recruited from the community.
For the DS group, initial visual assessment was successful in all individuals, and six eyes (21%) had clinically significant age-related cataracts. Usable OCT images were obtained in 33 DS and 46 control eyes. For the DS group, OCT imaging revealed the frequent presence of small dot opacities (16 eyes (48%)) scattered anteriorly and posteriorly throughout the cortex, and occasionally the nucleus (Figure 1). These had a significantly brighter intensity (Dot PIR: Mean±SD 1.33±0.12, p<0.0003) than nuclear PIR, and covered an area ranging from 0.2-14% of the cortex. However, there was no relation with age or VA in the PIRs or areas of these dot opacities (p>0.5). Mean (±SD) nuclear PIR was 1.20±0.06 in the DS group, comparable to controls (Mean±SD 1.24±0.04, F(2,23)=1.85, p=0.41). There was a significant relation with age and nuclear PIR in both groups (DS; R2=0.52, p<0.0001: Controls; R2=0.1, p<0.04).
Punctate dot opacities can be effectively imaged with AS-OCT and were seen frequently in DS lenses. VA is spared. Opacities, typically considered age-related, were also seen in individuals with DS as young as 26 years. Clinical assessment should include careful examination of the lens in DS.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Figure 1. Panel A: OCT of lens with dot opacities. B: Optic section of same eye
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