Subjective and Objective Refraction in Pseudophakic Patients
Targeting of post-cataract refraction depends mainly on the prediction of the post-operative lens position, but also on the post-operative refraction itself. Hence, aim of this study is to evaluate the agreement and variability of subjective refraction performed by two independent examiners, autorefraction, and wavefront aberrometry in pseudophakic patients after uneventful cataract surgery.
|Condition or Disease
One of the main goals of modern cataract surgery, beside removing the cataractous lens, is to achieve the patient's desired post-operative refraction. Targeting this post-operative refraction depends mainly on the prediction of the post-operative lens position and the post-operative refraction itself. Reason for the contributing effect of post-operative refraction in the error-propagation analyses is that refraction in phakic patients was shown to have only moderate reproducibility.
In the past, different studies evaluated refraction methods. However, there is no study that included reproducibility of subjective refraction in pseudophakic patients and compares it with objective refraction methods (autorefraction, wavefront aberrometry).
100 eyes of 100 patients, which underwent uneventful cataract surgery, will be included in the study. Refraction of one eye of each patient will be tested using subjective refraction by two different examiners, autorefraction, and wavefront aberrometry at two separate occasions.
Arms and Interventions
|Other: Refraction reproducibility and agreement
Subjective and objective refraction will be performed in all patients
Device: Subjective refraction
Subjective refraction measurements will be performed by two testers for all the patients included
Five autorefraction measurements will be performed for all the patients included
Device: Wavefront aberrometry
Five wavefront measurements will be performed for all the patients included
Primary Outcome Measures
- Evaluation of the agreement between the subjective refraction measurements (in dioptres) of two examiners [12 months]
To show the number of measurements within the limits of agreement, Bland-Altman plots will be created for subjective refraction measurements in dioptres between examiner 1 and examiner 2.
Secondary Outcome Measures
- Evaluation of reproducibility between the subjective refraction measurements between two study visits [12 months]
To compare reproducibility of subjective refraction measurements between study visit 1 and study visit 2 Wilcoxon-signed rank test will be applied.
- Evaluation of the agreement between the measurements performed by subjective refraction, autorefraction, and wavefront aberrometry (in dioptres) [12 months]
To show the number of measurements within the limits of agreement, Bland-Altman plots will be created for subjective refraction measurements in dioptres between the 3 measurement methods.
- Evaluation of the reproducibility between measurements done with subjective refraction, autorefraction, and wavefront aberrometry in dioptres [12 months]
To compare reproducibility between the 3 measurement methods in dioptres, Friedman's multiple comparison will be applied.
Minimum age: 21 years
Cataract surgery (at least 8 weeks post-surgery)
written informed consent
Complications during or after cataract surgery
Ophthalmic diseases, that might interfere with measurements (macular degeneration, glaucoma, diabetic retinopathia)
Ophthalmic surgery other than cataract surgery
Clinically significant posterior capsule opacification
Contacts and Locations
|Vienna Institute for Research in Ocular Surgery (VIROS)
Sponsors and Collaborators
- Vienna Institute for Research in Ocular Surgery
- Principal Investigator: Oliver Findl, Prof., VIROS, Hanusch Hospital Vienna
Study Documents (Full-Text)None provided.