Case Study

Debilitating diplopia (double vision) Presbyope with high refractive difference in R and L eye

Presbyope with high refractive difference in R and L eye

THE PROBLEM

Third, fourth and sixth nerve palsies can cause debilitating diplopia. Strokes, lesions, car accidents, and systemic diseases such as diabetes and thyroid conditions can cause partial or total nerve palsies. Once the main cause of the palsy has been addressed, our goal is to help improve quality of life. If the nerve palsy has affected convergence, the patient can see well in the distance but struggle with reading.

Gary is a patient of mine struck down by a severe stroke, leaving him unable to walk, weaker RHS, slurred in speech and diplopia, which was worse for reading. He would follow an object one eye at a time temporally but was unable to reach straight ahead (especially with his RE) initially, but after a month of trying, he managed to be able to follow either eye across his midline, just. This meant he no longer had diplopia in the distance.

However, Gary is 69 years old and loves to read and with no accommodation stimulus left, he really struggled with the diplopia for near work. Short of covering one eye, he found relief with 2BI each eye for reading. The difficulty was that he did not tolerate any BI prism at distance. Two pairs in the nursing home is just too easily lost (or ‘borrowed’ by another person).

Jeff Greenwood, Optometrist

40 years’ experience

Greenwood Optical, Brisbane.

Reverse slab off prism flat top 28 bifocal

THE SOLUTION

Reverse Slab Off Prism Flat Top 28 Bifocal

Careful counsel along the way allowed this determined patient to grow into “wearing success”. Using as little seg offset as possible, we worked out a reading distance with a trial frame where reading became comfortable. It was surprisingly more comfortable to read much more closely (than 50cm without accommodation for a +2.00) at 30 to 33 and this made for a satisfied patient.

A most embracing way to help assist fusion in anisometropic induced tendency to diplopia at near, is to use Younger Optics’ slab off prism (flat top bifocal 28 segs). Younger kindly allowed us to trial a small (B I) left eye as well to soften the base down binocular difference, and it proved an aid to visual comfort.

Would you like to share a speciality lens case study with your peers?If so, please contact Craig Johnston – info@youngeroptics.com.au or 0476 834 342.