A Case Of Decompensated Phoria
Binocular diplopia is a complex condition involving the extra-ocular muscles and the oculo-motor(CNlll), trochlear (CNlV) and abducens (CNVl) cranial nerves. It has a variety of aetiologies, may be congenital or acquired, ranging from extra-ocular muscle lesion, idiopathic, accommodative, to vasculopathic, head or facial trauma, intracranial hypertension or hypotension, tumour, stroke, aneurysm, or autoimmune disease, which requiring co-management of experienced clinical optometrist and ophthalmologist or neurologist, or may require management of endocrinologist, head & neck or thoracic surgeon, depending to the aetiology.
Binocular diplopia is commonly presented, diagnosed and managed appropriately by the comprehensive optometrists without the need of any sophisticated digital equipment.
Mr Tan, age 52, an administrative officer, presented with complaint of ”seeing double” frequently for the past two months.
Elicitation:
He has no known family and personal medical and ocular history. His routine comprehensive health screening done few months ago was unremarkable. Other than taking health supplements, he was not on any medication.
Besides binocular diplopia he didn’t experience any other symptom. He described the double vision as one object appeared above the other, despite being able to see distance objects and read papers clearly with existing distance and near spectacles.
Current distance spec: R-7.50-1.00×95, L-7.75-0.75×80
Current near spec: R-5.75-1.00×95, L-5.75-0.75×80
He didn’t have any recent head or face trauma and also not participated in any high impact sports or activities.
He also reported the double vision was lesser on downward gaze and greater images separation when making upward gaze.
The present SV specatacles have been used for the past two years without any problem prior to “seeing double” recently.
Observation:
The spectacles appeared to be in good condition and rested well balanced on his nose-bridge and ears. The optical centers of both spectacles were accurately positioned.
He showed no unusual facial appearance or head posture, and absence of Ptosis.
Ocular Examination:
- Eyes remained straight and unmoved on Cover/Uncover and Alternating Cover tests.
- No limitation or aberrant eye movement in all diagnostic positions of gaze.
- No gross visual field defect on confrontation test, and RAPD is not present.
- Slit lamp examination found no abnormality of the eyelids and the anterior segment of eyes. Posteriorly, abnormal sign not seen in either eye with high plus fundus lens.
Refraction:
R-7.00-1.25 x 90 (6/6), L-7.25-1.00 x 80 (6/6). ADD+2.00 (N5).
Patient complaining of hard to focus on test letters and described letters appeared jumpy when seeing binocularly.
When presented a single test letter E with red filter only on the Right eye, he reported a red E appeared above the white E (picture a).
The two separated E became a single E (picture b) after a 3Δ base-up trial lens was inserted over Right side, and the binocular single vision maintained during all positions of gaze.
He also reported a comfortable and clear reading chart without jumpy text with the reading correction.
Management:
A symptom relieving 3D base-up Fresnel Prism was later issued to stick on right lens of the new SV spectacles as temporary remedy. A referral letter also issued for him to consult neuro-ophthalmologist to exclude other possible underlying cause of diplopia.
A year later, the patient confessed he did not consult any ophthalmologist because he found his vision was absolutely fine since then, but not when without the temporary prism “sticker”. He requested to have new spectacles made without the hazy appearance resulted from the press-on prism on the right lens.
His ocular conditions and visual functions were found to be stable after comprehensive examination was performed, new spectacles were prescribed for constant wear:
Distance: (PD=63mm)
R-7.00-1.25 x 90 / o.c.height 15mm, L-7.25-1.00 x 80 / o.c. height 19mm.
Reading: (PD=61mm)
R-5.00-1.25 x 90 / o.c. height 14mm, L-5.25-1.00 x 80 / o.c. height 18mm
He was advised again to follow up eye examination every six months for possible change of the decompensated phoria and visual correction.
By: ALAN CHONG Dip. Optom, FBDO CL.