What types of intraocular lenses (IOLs) are recommended for patients undergoing cataract surgery, particularly those with underlying conditions such as nephrotic syndrome, cirrhosis, or severe burns?

Types of Intraocular Lenses for Cataract Surgery

The American Academy of Ophthalmology recommends discussing multiple IOL options with patients, including standard monofocal, toric (for astigmatism correction), aspheric, multifocal, extended depth of focus, accommodating, and postoperatively power-adjustable lenses, with selection based on patient visual needs, ocular anatomy, and willingness to accept trade-offs between spectacle independence and optical side effects. 1

Standard Monofocal IOLs

• Monofocal IOLs remain the most commonly implanted lens type and are appropriate for most patients undergoing cataract surgery. 2
• These lenses provide excellent distance vision but require spectacles for near and intermediate tasks. 1
• Surgeons should discuss postoperative refractive options including bilateral emmetropia, bilateral myopia, and monovision to optimize functional outcomes. 1

Toric IOLs for Astigmatism Correction

• Toric IOLs provide significantly lower residual astigmatism than non-toric IOLs, even when corneal relaxing incisions are used, with Level I+ evidence supporting their use. 1, 3
• These lenses are designed for capsular bag implantation and require preoperative measurement of corneal cylinder and knowledge of surgically induced astigmatism. 1
• Adding posterior corneal measurements improves outcome accuracy, whether by nomogram or direct measurement. 1
• Accurate intraoperative alignment verification is critical, as even small deviations significantly impact astigmatism correction. 3

Aspheric IOLs

• Modern aspheric IOLs improve mesopic and scotopic contrast sensitivity and visual quality by reducing or eliminating spherical aberration. 1
• These lenses are less tolerant of tilt and decentration and should be avoided in patients with zonulopathy or zonular weakness. 1, 4
• Some surgeons match the asphericity of the IOL to corneal asphericity to maximize visual quality under low-light conditions. 1
• In patients with retinitis pigmentosa or other conditions causing zonular instability, standard spherical IOLs are preferred over aspheric designs. 4

Premium IOLs for Spectacle Independence

Multifocal and Extended Depth of Focus IOLs

• The American Academy of Ophthalmology recommends discussing multifocal and extended depth of focus IOLs with patients desiring reduced spectacle dependence, while clearly explaining that these advanced technology lenses incur additional costs not covered by medical insurance. 1, 5
• These lenses can reduce dependence on eyeglasses for multiple distances but may be associated with optical side effects including glare and halos. 5

Accommodating IOLs

• Accommodating IOLs represent another option for reducing spectacle dependence, though their mechanism and efficacy differ from multifocal designs. 1

Postoperatively Power-Adjustable IOLs

• These lenses allow for refractive fine-tuning after initial implantation, potentially improving final refractive outcomes. 1

IOL Material Considerations

• Hydrophobic acrylic IOLs are recommended to minimize posterior capsule opacification, particularly in patients at higher risk such as those with retinitis pigmentosa. 4

Special Considerations for Extreme Refractive Errors

High Myopia

• Patients with high myopia may require unique lens constants for plus and minus power IOLs that differ significantly from manufacturer recommendations due to IOL geometry. 1

Extreme Hyperopia

• For patients requiring IOL power beyond the available range, piggybacking two posterior chamber IOLs is possible, with one placed in the capsular bag and one in the sulcus to reduce interlenticular membrane formation risk. 1

IOL Power Calculation

• Multiple modern formulas are available including Barrett Universal II, Kane, Haigis, Hill-RBF, Hoffer Q, Holladay 1 and 2, Olsen, and SRK/T, with varying complexity and variables beyond basic keratometry and axial length. 1, 4
• Optimization of lens constants based on individual surgeon outcomes improves accuracy beyond manufacturer-supplied values. 1
• Intraoperative aberrometry can assist with IOL power selection and toric axis alignment, though it is not clear that it always improves outcomes. 3, 4

Critical Pitfalls to Avoid

• Do not use aspheric IOLs in patients with zonular weakness, as these designs are less tolerant of decentration and tilt. 1, 4
• Always verify toric IOL alignment intraoperatively regardless of marking method, as alignment accuracy is critical for optimal astigmatism correction. 3
• Ensure the IOL is well-centered in the capsular bag, particularly with aspheric designs. 4