An Uncommon Cause of Reading Problem
Case Study: An Uncommon Cause of Reading Problem.
Dr Daniel Chiu 
Presentation
Mr D.B. 77 yo male avid reader c/o difficulty reading books and newspaper gradually over last 3 years referred for possible bilateral ERM. Specifically reading problem when reading across the line horizontally. Reading is one of his remaining few important pleasure in life.
Past History
– Right macular focal laser 20 years ago for Type 1 macular telangiectasia (Coat’s Disease) with longstanding reduced Right acuity
– Severe Parkinson’s Disease
On Examination:
– RVA c +3.00 DS = 6/36
– LVA c +3.00 DS = 6/9
– BEO c 6/9
– N5 with +2.50 DS Add
– No ocular deviation or phoria on cover test near or distance
– Minimal lens opacities
– Minimal ERM clinically and normal fovea architecture on macular OCT
– Old Right foveal pigment changes from previous laser
– Severe rigidity and hypokinesia from Parkinson Disease
What is the likely cause for the patient’s reading symptoms?
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This case is quite unique in that the patient’s symptoms are specific to reading, particularly on scanning across horizontal lines of words. After ascertaining that there is no ocular deviation or motility issue, and lack of significant new macular pathology, I hypothesized that patient is having difficulty reading from peripheral spectacle lens aberration and prismatic effect.
He is using a +5.5D reading spectacle to read and due to his severe Parkinson’s Disease, he cannot move easily his head horizontally to read across lines like others. He can only rely on horizontal saccade to look through peripheral part of his thick reading spectacles to read across the line which I think is the main cause of his present symptoms.
More recent onset of reading symptoms in the last few years also does not support pre-existing Right macular pathology
What intervention would be recommended?
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Based on the above hypothesis, one can consider using contact lens to correct for reading need. Contact lens use posts difficulty because of his age and Parkinson Disease. I elect to offer him bilateral early cataract surgery with target refraction of -1.50DS. This is an uncommon indication for early cataract surgery.
Post-operatively, his reading problem totally resolved and was symptom-free with reading. Distance corrected acuities are unchanged in each eye.
What ocular problems may be found in Parkinson’s patients?
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Apart from the above unique problem due to use of high plus add for reading, Parkinson’s patients can rarely have a vertical gaze problem (progressive supranuclear palsy variety) and a problem of ocular surface from reduced blinking. Horizontal gaze and saccade is generally not affected. Hypokinetic head and neck movement also makes progressive multifocal much less useful as a reading aid.