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Accuracy of Intraocular Lens Power in High Myopia

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03394300
Recruitment Status : Unknown
Verified January 2018 by salma safwat abdelhady mangora, Assiut University.
Recruitment status was:  Not yet recruiting
First Posted : January 9, 2018
Last Update Posted : January 9, 2018
Information provided by (Responsible Party):
salma safwat abdelhady mangora, Assiut University

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

Condition or disease Intervention/treatment
High Myopia 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

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

Resource links provided by the National Library of Medicine

Intervention Details:
  • Other: iol power calculation
    iol power calculation in high myopia

Primary Outcome Measures :
  1. accuracy of iol power in high myopia [ Time Frame: one year ]
    biometry assment of IOLpower

Information from the National Library of Medicine

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Ages Eligible for Study:   30 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Sampling Method:   Probability Sample
Study Population
data will be collected from all patients who meet inclusion criteria

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.
Additional Information:

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Responsible Party: salma safwat abdelhady mangora, ophthalmology resident, Assiut University Identifier: NCT03394300    
Other Study ID Numbers: 29110202500209
First Posted: January 9, 2018    Key Record Dates
Last Update Posted: January 9, 2018
Last Verified: January 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Plan Description: Evaluation of accuracy of IOL power calculation in high myopia.

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Refractive Errors
Eye Diseases