Accuracy of Intraocular Lens Power in High Myopia

Sponsor
Assiut University (Other)
Overall Status
Unknown status
CT.gov ID
NCT03394300
Collaborator
(none)
30
12

Study Details

Study Description

Brief Summary

evaluation of the accuracy of iol power in high myopia using different biometry formula & iol master

Condition or Disease Intervention/Treatment Phase
  • Other: iol power calculation

Detailed Description

High myopia or pathological myopia is associated with elongation of axial length longer than 26 mm or refractive error at least-6 diopter.

High myopia is one of the most prevalent refractive condition globally with a higher risk of other eye conditions Moreover in high myopic eyes the incidence of cataract is significantly higher than in non myopic eyes and the progression is also faster.

Calculation of IOL in high myopic eyes remains a challenge often leading to unexpected postoperative hyperopia the main potential sources of errors in IOL calculation for high myopic eyes include AL measurement & IOL constants used &IOL power calculation formula used.

investigators suspect that the SRK I1 formula is inaccurate for myopic eyes, and that new formulas are needed, taking into account all those factors that make up the dioptric power of an eye.

Formulas for IOL power calculation had past four generations, first generation formulas were theoretical and based on the same fundamental constant with no respect to anterior chamber depth. Since then, Binkhorst, Holladay, Hoffer and Shammas had refined the existing theoretical formulas where each of them developed his regression formula based on analysis of their previous IOL cases .

This work was amalgamated in 1980 and yielded the Sanders Retzlaff Kraff I (SRKI) formula The second generation was designed by combining linear regression analysis and stepwise adjustment for long and short eyes according to anterior chamber depth .

The third and fourth generation formulas, started by Holladay in 1988, all aimed at better calculation of the IOL power in eyes with extreme axial length where another term had appeared which is IOL specific anterior chamber depth .

The accuracy of third and fourth generation formulas for IOL calculation in patients with high axial myopia had not been fully evaluated For that, the need for more studies conducted to evaluate such accuracy is crucial.

This study will be conducted to evaluate the accuracy of different formulas used for IOL power calculation in patients with high axial myopia undergoing cataract surgery

Study Design

Study Type:
Observational [Patient Registry]
Anticipated Enrollment :
30 participants
Observational Model:
Case-Crossover
Time Perspective:
Prospective
Official Title:
Accuracy of Intraocular Lens Power in High Myopia
Anticipated Study Start Date :
Feb 1, 2018
Anticipated Primary Completion Date :
Feb 1, 2019
Anticipated Study Completion Date :
Feb 1, 2019

Outcome Measures

Primary Outcome Measures

  1. accuracy of iol power in high myopia [one year]

    biometry assment of IOLpower

Eligibility Criteria

Criteria

Ages Eligible for Study:
30 Years to 60 Years
Sexes Eligible for Study:
All
Inclusion Criteria:
  • 1- patients with clear lense extraction or cataract & high myope with{ AL more than 26 mm.

2-their IOLpower is less than 15 diopter or their refraction before operation is more than -6.

Exclusion Criteria:
  1. Keratoconus patients or those with irregular cornea

  2. Patients with post operative complications like posterior capsule injury or vitrous loss.

  3. patients who had undergone previous intraocular surgery at anterior segment or posterior segment.

Contacts and Locations

Locations

No locations specified.

Sponsors and Collaborators

  • Assiut University

Investigators

None specified.

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.
Responsible Party:
salma safwat abdelhady mangora, ophthalmology resident, Assiut University
ClinicalTrials.gov Identifier:
NCT03394300
Other Study ID Numbers:
  • 29110202500209
First Posted:
Jan 9, 2018
Last Update Posted:
Jan 9, 2018
Last Verified:
Jan 1, 2018
Individual Participant Data (IPD) Sharing Statement:
Undecided
Plan to Share IPD:
Undecided
Studies a U.S. FDA-regulated Drug Product:
No
Studies a U.S. FDA-regulated Device Product:
No
Additional relevant MeSH terms:

Study Results

No Results Posted as of Jan 9, 2018