24/11/2020
Mr Tan came to make a new pair of glasses. He sees double vision after an eyelid surgery, in which he needs prism to rectify the issue, or night driving can be very difficult.
Mr Tan is on monovision, one eye is optimised for far vision and the other eye is optimised for near vision. His right eye is optimised for far & left eye’s power is lowered to facilitate for near vision as well. He came 1month ago, and he also brought along his eye report from orthoptist indicating his left eye in need of prism.
Still facing some issues seeing double vision with his old glasses, Mr Tan also uses Fresnel prism (a thin, transparent plastic sheet) to stick on his spectacle lenses or sunglasses in order to see better when driving, which has caused the coating of his spectacle lenses peeled off a lot.
Upon wearing new glasses made with us, Mr Tan still faced the same issue. This double vision has bothered him for a long time and this time around, he has also gone to see an ophthalmologist as well, in which he has made another new pair of glasses at the eye hospital.
My sincerest apology to you Mr Tan for all the trouble that you have been through, for I missed rectifying prism that must be embedded in your lens for a comfortable vision. Thank you for sharing your visit with ophthalmologist, orthoptist & optometrists at the eye hospital with me & bringing your new glasses to me, allowing a chance for me to learn from my mistake.
With no prism embedded in your lens, we have sent back for replacement lens. And again, replacement lens came without prism and we had to send the lens back for replacement yet another time. After 1 month, the lens is finally ready with prism all in place.
Mr Tan, please accept my sincerest apology.. I’m sorry.
Chaw Zi Wen, Chaw optometrist
* Thank you to ophthalmologist, orthoptist & optometrists at the eye hospital
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Mr Tan (M/64) came for eye examination to make glasses, after he did cataract surgery in both eyes few months ago. Previously, he had very high myopia/shortsightedness around -9.00 to -10.00 and he needed prism correction in left eye to rectify his double vision. He has been very happy after the surgery as he wakes up seeing clearly now.
Vision without glasses
R: 6/9-, 6/7.5-
L: 6/6
Examination shows:
R: +1.00/-0.75×25 (6/6) (+1.25 blur lens test 6/7.5-)
L: +0.50/-0.25×20 (6/6) (+1.00 blur lens test 6/9-) [L: left dominant eye] L=R (adding +0.25 on L: R>L)
Add: +2.50 (N5@40cm) (his range of clear vision,ROCV can push so much nearer to eyes & still seeing clearly)
No further hyperopic power is accepted binocularly
No double vision reported on far vision during trial framing
Other assessments show:
Examination of Eye Alignment/Vergence (Cover Test)
small EP, fast recovery @ Distance
NMD @ Near
(normal value: orthophoria/NMD-No Movement Detected or small XP, fast recovery)
EP = Esophoria is misalignment of the eye, eye is deviated inwards
XP = Exophoria is misalignment of the eye, eye is deviated outwards
Examination of Eye Alignment/Posture (Howell Card) by 6^ Base Down on Right eye
Distance: 1 – 3 EP (yellow part), top arrow stops at 3 yellow
+1.00 Distance: 1 – 3 EP (yellow part)
Near: 0 – 2 XP (blue part)
(normal value: 0-1 EP or 0-3 XP @Distance and 0-6 XP @Near)
EP = Esophoria is misalignment of the eye, eye is deviated inwards
XP = Exophoria is misalignment of the eye, eye is deviated outwards
NRA (Accommodation analysis – ability to relax accommodation) by plus lens
+1.50
(normal value: +1.50 to +2.50)
PRA (Accommodation analysis – ability to stimulate accommodation) by minus lens
-1.00
(normal value: -1.37 to -3.37)
Mr Tan has some longsightedness/hyperopia/plus power with mild astigmatism. He has a readymade reading glasses to see near. Sometimes, when he is driving on long, straight road like highway (on concentrated focus @far), he notices that car in front will “split” & becomes like 2 cars. He tried wearing his readymade reading glasses.. car did not seem to “split into 2cars” but just that his vision is blurry. He has some esophoria at distance, plus power is indicated to relax/relieve the esophoric posture.. possibly explain no “car splitting into 2” is seen upon wearing his reading glasses (as reading glasses are of plus power). With 1 – 3 esophoria.. during concentrated task at far, eyes will break down into tropia/squint hence seeing double vision? We will have a look at his fusional reserves when he comes.
We prescribe max plus power for distance to let him try during driving as well as for fulltime wear.. in hope to relax his eyes over time.. not wearing correction may mean that eyes would be tensed up thus esophoria wont get a chance to be relieved? We understand that he would like to enjoy spectacle free.. we will try with contact lenses to see his far eye posture in contact lens too.
*Updated
Examination of Fusional Reserves (Convergent/Divergent reserve stamina) by Prism Bar
Distance, Base-In/Divergent, NFV: 6/4
(normal value: Break/Recovery)
Near, PFV: 10-28/7-21
Near, NFV: 7-19/5-15
Distance, PFV: 4-18/5-9
Distance, NFV: 4-10/2-6
[Scheiman – Adult Data]
Examination of Eye Alignment/Posture (Howell Card) by 6^ Base Down on Right eye
1 BO OU Distance: 3 EP (yellow part)
2 BO OU Distance: 3 EP (yellow part)
3 BO OU Distance: 1 EP (yellow part)
1 BI OU Distance: 5 – 7 EP (yellow part)
Contact lenses Distance: 5 – 7 EP (yellow part)
(normal value: 0-1 EP or 0-3 XP @Distance and 0-6 XP @Near)
EP = Esophoria is misalignment of the eye, eye is deviated inwards
XP = Exophoria is misalignment of the eye, eye is deviated outwards
Mr Tan brought along his ready-made reading glasses that he mentioned using them for driving. It is +2.50 with a stick-on Fresnel 4BO on left eye that was prescribed by his orthoptist previously. According to orthoptist’s report, he is diagnosed as decompensated distant eso with right lateral rectus muscle weakness with AHP noted since many years ago.