Comparison of different aspects in Contact lenses and spectacles are given below.
Field of view:
When you wear spectacles, the field of view decreases towards periphery. Because you can see clearly only through glasses and in the periphery due to the space between the spectacles and eye, vision is blurred. The rim of the spectacle also plays an important role in restricting the field of view. Peripheral vision is not restricted in Contact lenses.
Minimum magnification and minification:
Myopia is treated by negative lenses. The eyes behind the negative lens appear small (Minification). For a high myope it is more prominent. Slight double image is seen in a high myopia. Hyperopia and presbyopia are treated by positive lenses which makes eyes to appear larger (Magnification). Both of these problems are reduced to a large extent by using Contact lenses.
High power glasses:
They are very thick which increases the aberrations resulting decrease in visual clarity. Weight of the glasses is very high. High positive glasses causes’ pincushion effect and high negative glasses causes barrel effect. Contact lenses serves this purpose well.
Persons with unilateral or bilateral aphakia will have to use high powered plus lenses. Contact lens serves a better option to reduce pincushion effect.
Sports persons and dancers:
Spectacles fall off from the eyes while playing or dancing. Elastic band/straps can be used to avoid this problem. Contact lens does not fall off from the eye as spectacles while playing or dancing. It does not interrupt the work.
Watching 3D movie:
It would be very uncomfortable to wear 3D glasses over normal spectacles. There are specially manufactured spectacles called polarizers which would be helpful in watching 3D movies. But you can’t buy them just for a movie. If you opt for contact lens you can wear 3D glasses easily over your eyes.
Fogging up in cold weather:
While you are in cold weather, the spectacles get fogged up easily and needs to be wiped off. To avoid this, Anti fog coating can be done over the glasses but this is not effective much. There is no such fogging in Contact lenses.
There are reflections from the back surface the spectacles where as contact lenses doesn’t have these reflections. Anti reflection coating is available which reduces the reflections to some extent.
Wearing spectacles makes us feel like an obstruction in the vision. Contact lenses are directly placed over the cornea Hence there is no such problem.
Contact lenses must be kept more clean and hygienic than spectacles. This makes the person to be more conscious on hygiene.
As far as the patient is hygienic there is no point of infections while using contact lenses. If there is any sudden onset of infections for contact lens wearer it’s better to use spectacles.
Spectacles or Contact lenses must be replaced only after the ophthalmic consultation. Spectacles are replaced when your vision is blurry with them or got scratches,lost or broken. Contact lenses are replaced when you have blurred vision with them or scratches,tears or any other defects and when the wear schedule is completed.
The patient should practice insertion, removal and maintenance of the Contact lenses. The spectacles maintenance doesn’t need any practice.
Fall asleep accidentally:
When you fall asleep suddenly with your glasses, there is a chance of someone removing your glasses and placing them off your eyes. But if you wear Contact lenses and fall asleep unintentionally the cornea(outer transparent layer over your brown or black part) would be deprived of oxygen and may result in serious complications. There are contact lenses available which can be worn during sleep(Extended wear).
For Contact lenses you need to maintain a contact lens solution and Lens case. For spectacles, have lens box and a microfiber cloth.
Many of the disadvantages of the contact lens are due to non-compliance of the patient. At the end, even if you are using contact lens you have to have a spare spectacles to wear during sudden unexpected infection or ocular injury.