In the past, if you had cataract, you had to wait till your cataract was ‘ripe and mature’ before having it removed. Today, it can be taken off as soon as a cataract interferes with day to day professional or personal activities like watching television, driving, climbing stairs, playing games, cooking and reading etc. Cataracts significantly reduce a person’s ‘blue light’ perception. This happens as cataracts have blue light (short wave length light) blocking effect. Given that cataract is a slowly progressive disease, human mind does not perceive the alteration of color and slowly adapts to reduced blue color perception. Hence, after surgery, some patients see ‘blue’ with the eye, as compared to the other non-operated eye. This is normal. The ability to perceive colors in their correct form returns to normalcy within a few weeks after cataract surgery.
“Shyam underwent a very successful cataract surgery. His joy knew no bounds as he could read the full vision chart the first day after his cataract surgery. This was the first time in a long time that he could see so clearly and that too without the use of glass. After a week he got his other eye cataract surgery done as well. He took a few days off from his professional responsibilities. He is a tailor by profession. One week later he complained to me that all the threads have a hint of blue in them! He was very disturbed as his profession entailed appreciating colors and using them in various mixes“.
I could understand his dilemma and concerns. I reassured and explained to him the reasons behind the high blue light perception and after a while Shyam calmed down enough to wait it out. As of now he is happily enjoying his restored vision and his work.
Let’s first of all understand the various situations related to blue light transmission and perceptions in the human eye before and after the cataract surgery and whether there really is a need for any special IOL’s –
- Normal Adaption – I think it is important to counsel and explain to patients about the effect of lens on blue light transmission into the eye. Crystalline lens (natural lens) blocks out a proportion of blue light naturally with an increasing amount of blue light blocked with age. This happens due to increasing cataract. Replacing the crystalline lens with an artificial intra ocular lens increases blue light transmission. Patients often comment that everything looks ‘bluer’ after cataract surgery. This is normal and brain adapts to this in some time.
- Blue light blocking IOL (Intra Ocular Lens)– In special situations like those where patients have pre-existent Age Related Macular Degeneration (ARMD) it may be wise to go for IOL’s which have a selective blue light reducing/blocking effect. Though not proven, it is believed that blue light exposure may enhance the progression of ARMD in the retina. The use of a blue-blocking IOL is defensible on the basis of its biological plausibility and may offer significant health care savings on the long run, given the increasingly aging population.
- Cognitive function in elderly population– Blue light transmission increases after a cataract surgery and that may improve the sleep wake cycle, mood and cognitive functions like reaction times etc. Aging is associated with insomnia, depression and cognitive decline. Removal of opaque cataract lens and replacement with a clear intra ocular lens (IOL’s) with increased blue-light transmission has potential benefits to some brain responses, the human natural body rhythm and its associated effects on the body.
So overall lets just say that there are no clear guidelines or recommendations on the type of lens that should be implanted after cataract surgery. While blocking of blue light may be beneficial for retina and not blocking it may be important for other body functions. It is most important to understand that some amount of blueness will temporarily increase in everything even after the best of the cataract surgery and that is not a side effect of cataract surgery. In the recovery period after the cataract surgery the human brain is adapting its perception of colors and readjusting it to it’s original status.