Comparative Study of Three IOL Power Calculation Formulae for Asian Eyes Shorter Than 22mm or Longer Than 25mm

Launched by SINGAPORE NATIONAL EYE CENTRE · Jun 30, 2006

Keywords

ClinConnect Summary

Our primary objective is to compare three IOL power calculation formulae and determine the most appropriate formula for accurate prediction of postoperative refractive error in Asian eyes with axial length less than 22mm and greater than 25mm that are undergoing phacoemulsification cataract surgery.

This will be a randomized prospective study in patients with axial lengths less than 22mm and greater than 25mm undergoing phacoemulsification cataract surgery and IOL implantation. Each patient will be randomly assigned to have their IOL power calculated using one of three IOL power calculatio...

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • 1. Eyes with significant cataract and suitable for phacoemulsification and primary implantation of posterior chamber intraocular lens.
• • 2. Cataract as the only ophthalmic pathology causing significant visual impairment.
• • 3. Axial length less than 22mm or more than 25mm, as measured by Zeiss IOL Master.
• • 4. Evidence of a personally signed and dated informed consent document indicating the patient (or a legally acceptable representative) has been informed of all pertinent aspects of the trial.
• • 5. Patient is willing and able to comply with scheduled visits and other study procedures.
• Exclusion Criteria:
• • 1. Presence of other ophthalmic pathology causing visual impairment: amblyopia, glaucoma, optic neuropathy, age related macular degeneration, macular oedema, retinal detachment, proliferative diabetic retinopathy, ocular inflammation.
• • 2. Previous intraocular or corneal surgery (including refractive surgery).
• • 3. Corneal opacities or irregularities: previous scarring, dystrophy, ectasia
• • 4. Corneal astigmatism greater than 1.5 dioptres.
• • 5. Axial length unable to be measured by the Zeiss IOL master.
• • 6. Other ocular surgery at time of cataract extraction.
• • 7. Uncontrolled diabetes.
• • 8. Any neurological condition which may interfere with performance of required tests.
• • 9. Other severe acute or chronic medical or psychiatric condition that may increase the risk associated with study participation or may interfere with the interpretation of study results.
• • Surgical exclusion criteria
• The patient will not be included in the study if any of the following complications are encountered during surgery:
• • 1. Inability to achieve secure 'in-the-bag' placement of the IOL (i.e. due to posterior capsule rupture, radial tear in capsulorhexis, vitreous loss, zonular rupture)
• • 2. Use of corneal sutures.
• • 3. Multiple operative procedures at the time of IOL implantation.
• Post-implantation exclusion criteria:
• • 4. Haptic not in the capsular bag.
• • 5. Decentration of the IOL of more than 1.0mm.
• • 6. Other ocular pathology causing visual impairment that were not apparent prior to surgery (e.g. age related macular degeneration, macular oedema, glaucoma, retinal detachment).