Comparison Between Different Investigations Used in Intraocular Lens Calculation in High Myopic Cataractous Patients

Study Overview
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Brief Summary
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the purpose of the study is to compare the accuracy of optical and ultrasonic biometry in intraocular lens (IOL) calculation in high myopic cataractous patients

Detailed Description
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Prospective interventional (QUASI experimental) comparative study This study will be conducted on high myopic cataractous patients scheduled for phacoemulsification and IOL implantation in department of ophthalmology, Sohag university patients will be divided into 2 groups one will be subjected to intraocular lens (IOL) calculation by optical biometry the second one will be subjected to intraocular lens (IOL) calculation by ultrasonic biometry postoperative auto refraction after I month

Official Title
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Optical Biometry Versus Ultrasonic Biometry in Intraocular Lens Calculation in High Myopic Cataractous Patients: A Comparative Study

Conditions
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Calculation of Intraocular Lens in High Myopic Cataractous Patients

Intervention / Treatment
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* Device: optical biometry
* Device: ultrasonic biometry


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients with simple cataract not associated with other pathologies suitable for phacoemulsification and 1ry IOL implantation With axial length (AXL) equal to or greater than 26.5mm Exclusion Criteria: History of trauma Associated pathologies such as optic neuropathy, age related macular degeneration, macular edema, retinal detachment, , ocular inflammation, retinitis pigmentosa, proliferative diabetic retinopathy corneal opacities or irregularities, scars, dystrophy or ectasia Patients who underwent previous corneal surgery (including refractive surgery) Patients having intraoperative complications as inability to achieve secure 'in the bag' placement of the IOL (i.e. due to posterior capsule rupture, vitreous loss, weak zonules, or zonular rupture)

Ages Eligible for Study
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Minimum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: optical biometry<br> | Device: optical biometry<br>* optical biometry is a fast, noncontact method it uses the method of partial coherence interferometry (PCI) to measure the axial length (AXL), based on reflection of the interference signal of the retinal pigment epithelium.<br>|
| Experimental: ultrasonic biometry<br> | Device: ultrasonic biometry<br>* ultrasonic biometry is contact method depends on ultrasonic transducer producing thin sound beam travelling through different media of the eye when it faces interface of substance dissimilar from that it is travelling through part is reflecting and the other travel through the different substance<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| desired post operative refraction | detection of postoperative refraction by the use of autorefractor (one of the objective methods of assessment of refraction) after use of IOL power calculated by different investigations (optical vs ultrasonic) | postoperative refraction 1 month |