Go to see an ophthalmologist,
I am 60 years old, I went yesterday to BKK Hospital for a eye checkup. I suspected I got cataract on my left eye base on the symptoms I got and I was right. You will get a Ultrasound A-Scan as they enable the Opthalmologist to determine the power of the intraocular lens (IOL) needed for the artificial implant and an OCT Optical Coherence Tomography (OCT) is used to provide eye doctors with an image of the retina in the back of a patient's eye, adding the Opthalmologist fee and you will get a cost of around $6.6K bahts. then, later you go for a lense replacement, mono, bi or tri-focal to see form near, middle and far, your choice. Tri-focal is around $140K bahts (for one eye). My insurance do not cover cataracts unfortunately, so everything is out of my pocket. Yes, it is expensive, but the peace of mind is there, knowing it is top quality healthcare services. I do not know the price for something equivalent with Rutnin hospital, but I will ask anyway.