Multiple insulin injections for small dog

Question
My 13 year old Shih-tzu has diabetes. Diagnosed four months ago. He has had four hospital stays for glucose curve. Currently, the vet advised me to give him 8 units of insulin in the morning and 8 units at night.
Meanwhile, he developed cataracts and is mostly blind, as well as mostly deaf.
He still eats, sleeps, pees and poops, but suffers from cognitive disorders everyday between the hours of 7 a.m. and 9 a.m. and 7 p.m. and 9 p.m.  He is normal at other times of the day.
Could it be that during those times, his glucose levels are too high?  I give him the shot at 7 a.m. and 7 p.m.  
Should I try giving him the same amount of insulin a day (16 units) at 8 hour intervals instead of 12?  Would that be worth trying?  
I just hate to make this dog go through another lengthy hospital visit at this time.  It seems to take the life out of him.  He's the love of the my life and I feel at this point, I am losing the battle.  
My plan would be to feed him at 7 and give 5.3 units of insulin, then feed him again at 3 p.m. and give another 5.3 units and then again at 11 p.m.  Same amount of food, same amount of insulin, just spread into three feedings instead of two.  Could this harm him? Could this help level him out? The last visit to the vet his levels remained between 500 and 200.  Too high if you ask me.

Answer
Susan,

I wish I could help you regarding dosing and management of your puppy's diabetes.  Unfortunately, since I have never examined him, I can not give specific medical advice.  However, you bring up some good questions that probably should be answered at some point by someone.

Dog's with diabetes should be closely managed because, like humans, unlike cats, they do not tolerate large fluctuations in their blood sugar levels without side effects such as those you have described.  For this reason, I will personally teach my clients how to do their own blood sugar curves at home.  Not only are the home curves more accurate but you can better predict what is happening based on either too high blood sugar or too low blood sugar levels.  I think that only way to regulate dogs is with an parent who is willing to put in the time and effort it takes to draw blood themselves and monitor their pets.  By doing this, I've successfully regulated diabetic dogs with simple phone calls back and forth.

I suggest you speak with your vet about learning how to monitor blood sugar at home.  If they will not teach you, there are websites you can go to, or simply call other vet clinics to see if they can help you.  I have one client that did this.  She called us because she wanted to monitor her cat at home and her vet said no, they had to come in for glucose curves.  She came here, learned how to perform glucose curves and got her cat managed quickly.  (She also went home with a little diabetic poodle that we had been trying to find a home for but that is a whole 'nother story ;-)

Good Luck to you.