What is the difference between monofocal, multifocal and toric intraocular lenses implanted during cataract surgery?
The natural lens in the eye has some refractive power to focus the light beam going inside the eye onto the retina. When this lens is removed during cataract surgery, a plastic lens called intraocular lens (IOL) is implanted in the place of the natural lens to do its function.
Monofocal IOLs give the best possible vision for one distance chosen by the patient but patients will need glasses for other distances. For example, if the patient chose to see perfectly well for distance without glasses, then she/he will need glasses for reading newspapers and computers. Or if the patient chose to read without glasses then she/he will need distance glasses and so on. Having said the above, it is difficult to give 100% guarantee of glasses free vision in all cases. Please, discuss your particular case with the surgeon.
Multifocal IOLs provide reasonable vision without glasses for distance and reading. There are many designs in the market. Some gives very good vision for distance, intermediate distances – computers and near reading but the patient might find it more difficult to see in dim light, in particular reading in dim surrounding. In addition, patients usually get glare when driving at night from coming lights. With time the brain gets used to the above side effects. Multifocal IOL is a trade-off patients do by losing some of the perfect quality of vision of monofocal IOLs for the sake of seeing for distance and near without glasses.
For patients looking for perfection of vision, I do not recommend multifocal IOL. However, if a patient is happy with the above trade-off, then many of them are very satisfied with their multifocal lenses. Some multifocal IOLs provide better vision for distance and computer reading with less glare compared to IOL that provide good vision for distance, intermediate computer and near newspaper reading.
Again, it is difficult to give 100% guarantee of glasses free vision in all cases. Please, discuss your particular case with the surgeon.
Toric IOLs are available in monofocal and multifocal lenses and they correct the astigmatism in the eye. The astigmatism is a very common condition available in about 30% of population. After cataract surgery, it is caused by the shape of the cornea: Ideally should be spherical so all the parts of the cornea refract the light with the same power, whereas in many people the corneal shape is not ideally spherical, hence different parts of the cornea refract the light with different powers and toric IOLs correct this discrepancy.
The choice of the intra-ocular lens is not an easy decision and require frank discussion with your surgeon.
Cataracts can be removed by using lasers?
Yes, cataracts can be removed using lasers in a procedure called Femto-phaco. However, this technique provided little benefit if at all compared to traditional ultrasound technique – phacoemulsification.
During cataract surgery, a small cut is made in the cornea, a circular window is cut in the front part of the capsular bag (the capsule that contains the opacified lens) then the cataract itself is removed by transforming it from hard state to liquid state using ultrasound power. With Femto laser, only the above stages are performed with the laser, you still need the ultrasound energy in many cases. Cleaning the remaining soft lens matter and inserting the intraocular lenses are the same in both techniques of surgery.
Visual outcome and complication rate is the same though some audits reported higher complication rate in Femto-phaco due to the learning curve. Femto-phaco takes longer to do as it is done in two stages on the same day, one under the laser machine and next step on the traditional phacoemulsification machine
Femto-phaco might have limited benefit in extremely dense cataracts. In many cases, it is done for the extra charge and the “exciting sound” of laser surgery.
Can cataracts grow back?
No, cataracts never grow back. The cataract is enveloped in a thin membranous bag called capsular bag. During surgery, a circular window is cut in the front part of the capsular bag then the cataract itself is removed by transforming it from hard state to liquid state using ultrasound power. Finally, an intraocular lens is implanted in the capsular bag. In 15-25% of patients after cataract surgery and within the next few years, the back part of the capsular bag becomes opacified/cloudy and that is when some people think the “cataract came back”. Capsular bag opacification is treated in clinic with a short “5 minutes” painless procedure by opening a small window in the capsule using laser.
If I have 20/20 vision and no symptoms, will I develop glaucoma?
Glaucoma is an optic nerve disease that shows progressive damage to the nerve on the back of the eye often but not always with raised intraocular pressure. In general, glaucoma does not affect vision until late stages hence it is common to see people with mild to moderated glaucoma with 20/20 vision. Early treatment stabilises or slow down the progression of the damage to the optic nerve and prevent irreversible blindness.
Can glaucoma affect young people?
Although glaucoma is much more common in patients aged 50 and above, however it could happen at any age even in children and new-born babies. In addition, glaucoma could happen as a secondary process to other eye diseases like inflammation inside the eye, bursting retinal veins due to occlusion, bleeding inside the eye and as a complication of eye surgery. There are many other diseases that could lead to glaucoma