All ETDs from UAB

Advisory Committee Chair

Cynthia Owsley

Advisory Committee Members

Roderick Fullard

Paul Gamlin

Gerald McGwin Jr

Kristina Visscher

Document Type

Dissertation

Date of Award

2020

Degree Name by School

Doctor of Philosophy (PhD) School of Optometry

Abstract

Childhood permanent, uncorrectable vision impairment (VI) is rare, yet it is a public health burden as the impairment lasts a lifetime. Vision impairment describes decreased vision that affects everyday activities. Acuity cut-points commonly used include 20/40, 20/60 or 20/70. Blindness often refers to legal blindness (best corrected visual acuity of 20/200 or worse or a visual field less than 20 degrees). Children with VI often have hereditary conditions such as albinism, optic atrophy and retinal degenerations and are different in many ways than adults with VI. The majority have conditions with onset at or near birth and as a result also have nystagmus. Despite this, relatively little is known about the best rehabilitation strategies to ameliorate the symptoms caused by VI. This dissertation focuses on measuring 3 aspects of pediatric VI: quality of life, near focusing (accommodation) and reading. Here we have shown that the PedsQLTM 4.0, a generic health related quality of life instrument, has excellent internal consistency reliability. It has good convergent validity as poorer visual acuity is associated with lower quality of life scores. The PedsQLTM 4.0 can discriminate between samples of children with normal vision and those with VI. Near accommodative accuracy was measured using a gold standard autorefraction method and a quick clinical test. Both tests found greater focusing inaccuracy for children with vision impairment and that the inaccuracy was greater for a 6D demand condition than 4D. Lastly, this work validated the use of the MNREAD for measuring reading in children with VI. Maximum reading rate and reading acuity had excellent test-retest repeatability. Critical print size showed more variability. The MNREAD test and a paragraph reading test, the Jerry Johns Basic Reading Inventory, were strongly correlated (p=0.88), however reading rates were faster on the MNREAD. Clinicians should be aware that MNREAD testing may over-estimate reading speeds expected for typical reading materials. The PedsQLTM 4.0, accommodative response testing and MNREAD testing are all valuable tools that can be used to evaluate function in children with VI. They should be considered as potential outcome measures for future studies on rehabilitation in pediatric VI.

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