"Treatment for ocular hypertension"

I have been on eye drops for ocular hypertension for the last 20 years or so. During this time, the original single drop I was using was upgraded to a combined drop as the pressures were gradually rising. This worked well in terms of keeping the pressures within a reasonable level, but I was experiencing some discomfort, and it was suggested that this was due to the preservative in the drops. I had appointments in December, and in January with the dr, when it was agreed that drops without preservative might be worth a try. I was prescribed a new eye drop, which I was led to believe was the same as my previous prescription. However, when I attended the hospital again in September, I was shocked to find the pressures had gone up to 38 in both eyes. I also learned that the drops I had been given were not the combined drop I had previously been on. I was immediately put on a third eye drop, together with the second, to try to get the situation under control.   The stress of this outcome caused me to suffer a series of migraines, and I feel it was something that never have happened in the first place.