Intraocular Lens Power and Corneal Topographic Change After Pterygium Surgery.

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Pterygium, a common ocular condition, can alter corneal topography.
• Accurate intraocular lens (IOL) power calculation is crucial for successful cataract surgery outcomes.
• The effect of pterygium excision on pre-operative IOL calculations requires further investigation.

Purpose of the Study:

• To evaluate the impact of pterygium excision on IOL power calculations.
• To assess changes in corneal astigmatism following pterygium surgery.
• To correlate pterygium size with refractive prediction errors.

Main Methods:

• Prospective cohort study involving 30 eyes with primary pterygium.
• Pre- and post-operative measurements of IOL power and corneal topography using IOL Master 700 and Pentacam.
• Analysis of pterygium length/area against IOL power and topographic changes over 12 months.

Main Results:

• Pterygium excision led to a significant reduction in calculated IOL power values one year post-surgery.
• Larger pterygium size (length/area) correlated with greater errors in IOL power calculation (0.5-1.0 D).
• Pterygia exceeding 1.83 mm in length or 5.1 mm² in area caused a 2.0 D error in anterior corneal astigmatism.

Conclusions:

• Pterygium significantly influences IOL power calculations, with larger pterygia causing more substantial refractive errors.
• Cataract surgery with IOL implantation is advised at least six months post-pterygium excision.
• A reduction of 0.5 to 1.5 D in calculated IOL power is recommended for combined pterygium and cataract cases.