THE CHOICE OF INTRAOCULAR LENS (IOL) TYPE FOR DISTANCE AND NEAR VISION CORRESCTION

The choice of intraocular lens (IOL) type for distance and near vision correction depends largely on the patient's visual needs, lifestyle, sensitivity to optical side effects, and expectations after cataract surgery. The following is a general order of choosing an IOL type based on its ability to correct distance and near vision, from the simplest to the most sophisticated.

1. Monofocal IOL (Standard)

• Correction : Only for one distance (usually long distance).
• Use of Glasses : Patients still need glasses for near and intermediate vision.
• Indications :
  • Patients who are only concerned with good distance vision and do not mind using glasses for reading or near activities.
• Profit :
  • Excellent visual quality for long distances.
  • Little or no optical side effects (halo/glare).
• Loss :
  • Does not provide independence from glasses.
  • Does not improve intermediate or near vision.

2. Monofocal Plus or Enhanced IOL

• Examples : TECNIS Eyhance, AcrySof IQ Vivity.
• Correction : Corrects distance vision with slight improvement in intermediate vision.
• Use of Glasses : Glasses are still needed for reading (near vision), but are not as intensive as standard monofocals.
• Indications :
  • Patients who desire good quality distance vision as well as slight improvement in intermediate vision, without significant optical side effects.
• Profit :
  • Intermediate vision is better than standard monofocals.
  • Minimal optical side effects (halo/glare).
• Loss :
  • Near vision still requires glasses.
  • Does not provide total independence from glasses.

3. Accommodating IOL

• Example : Crystalens (Bausch + Lomb).
• Correction : Provides better distance and intermediate vision, and in some cases helps with near vision by a lens shifting mechanism that follows the movement of the eye muscles.
• Use of Glasses : Glasses may still be needed for near-vision activities, such as reading small.
• Indications :
  • Patients who want good vision for distance and intermediate vision, as well as flexibility in near vision without over-reliance on glasses.
• Profit :
  • A natural transition between distance and intermediate vision.
  • Minimal optical side effects.
• Loss :
  • Independence for near vision may be less than optimal.
  • Doesn't always provide good enough near vision.

4. EDOF (Extended Depth of Focus) IOL

• Examples : TECNIS Symfony, AcrySof IQ Vivity.
• Correction : Provides excellent distance vision with improvement in intermediate vision, as well as some near vision ability.
• Use of Glasses : Glasses are usually still needed for very close viewing, such as reading small objects.
• Indications :
  • Patients who need good intermediate vision, for example to work in front of a computer or use gadgets, but do not mind using glasses for intense reading activities.
• Profit :
  • Smooth distance and intermediate vision without many optical side effects.
  • Minimal halo/glare side effects compared to trifocals.
• Loss :
  • Near vision may be less than optimal, and glasses may be needed for near activities.
  • Not completely free from glasses.

5. Bifocal Multifocal IOL

• Correction : Has two main focus points: distance and near vision.
• Use of Glasses : Patients may need glasses for intermediate vision, such as working at a computer.
• Indications :
  • Patients who want distance and near vision, but intermediate vision is not as important.
• Profit :
  • Helps provide independence from glasses for distance and near vision.
• Loss :
  • Intermediate vision is often less than optimal.
  • Optical side effects such as halos and glare are more common than with monofocal or EDOF IOLs.

6. Trifocal IOL

• Examples : PanOptix (Alcon), AT LISA Tri (Zeiss).
• Correction : Provides correction of distance, intermediate and near vision.
• Use of Glasses : In most cases, patients do not need glasses for distance, intermediate, and near vision.
• Indications :
  • Patients who desire maximum independence from glasses for all distances, and are prepared to accept possible optical side effects such as halos and glare.
• Profit :
  • High independence of glasses for vision at all distances.
• Loss :
  • More likely to cause optical side effects such as halos, glare, and decreased contrast in low light.
  • Requires longer visual adaptation.

7. Monovision IOL (Non-Special Lens Approach)

• Correction : One eye is adjusted for distance vision, and the other eye for near vision.
• Use of Glasses : Sometimes necessary for special tasks, especially for intermediate vision or when driving.
• Indications :
  • Patients who are tolerant of monovision and wish to minimize dependence on glasses.
• Profit :
  • A simple solution to overcome presbyopia without the need for multifocal lenses.
• Loss :
  • Not all patients are comfortable with a monovision setting as there may be decreased depth perception.

Conclusion

The order of IOL selection for distance and near vision correction starts from standard monofocal lenses to more advanced lenses such as trifocals and EDOFs. This order is based on the ability to provide spectacle-free vision at various distances, as well as possible optical side effects . IOL selection should be tailored to the patient's visual needs and preferences, as well as a thorough evaluation by an ophthalmologist.

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