Clinical trial NCT03856346: Intraocular Lens Power Calculation for Combined Phaco-vitrectomy Procedures
Official title: Intraocular Lens Power Calculation for Combined Phaco-vitrectomy Procedures: Calculation of a New Constant for Biometry IOL-formulas
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Intraocular Lens Calculation
Combined Phaco-vitrectomy
Keywords: Vitrectomy
Phacoemulsification
Biometry
IOL calculation
Cataract
Lead sponsor: Cantonal Hospital of St. Gallen
Sponsor class: OTHER
First posted: 2019-02-27
Enrollment: 200
Sex: ALL
Minimum age (years): 18
Maximum age (years): 99
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_ONLY
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: Patients who undergo a combined procedure with phacoemulsification and pars plana vitrectomy

Brief summary: The aim of the study is to evaluate the degree of refractive error postoperatively in combined procedures and to calculate a new constant in order to improve current state of the art biometry calculations.

Detailed description: The IOL power calculation in combined phaco-vitrectomy has been performed similar to that in cataract surgery alone. In patients who undergo combined phaco-vitrectomy, deviations in refractive outcomes may be observed because of possible errors in measurement of axial length, changes in the properties of the vitreous cavity after removal of the vitreous, or intraocular tamponade. Most of the previous studies have reported variable degrees of myopic shift after phaco-vitrectomy for diabetic retinopathy, epiretinal membrane, and macular hole. Furthermore, use of intraoperative gas may increase further the risk of anterior displacement of the intraocular lens which may induce a higher myopic shift. However, these publications did not provide any quantification of the spherical deviations nor calculate any specific constant in order to improve currents state of art biometry calculations.

Eligibility criteria: Inclusion Criteria:

* Patients who undergo a combined procedure with phacoemulsification and pars plana vitrectomy

Exclusion Criteria:

* Sulcus fixation of the IOL, sulcus suture of the IOL, or intra-scleral IOL fixation because of intraoperative posterior capsule rupture
* corneal disease, such as keratoconus, that interfered with refractive results
* IOL implantation with a toric IOL or multifocal IOL
* History of previous vitrectomy or corneal transplantation
* Other coexisting ocular disease such as proliferative diabetic retinopathy, advanced age-related macular degeneration, uveitis, acute retinal necrosis, Coat's disease, proliferative vitreous retinopathy, or trauma
* Intraocular tamponade using silicon oil

Primary outcomes:
measure: Refractive prediction error (measured by subjective refraction, in diopters)
timeFrame: 6 weeks postoperatively
measure: Absolute prediction error (measured by subjective refraction, in diopters)
timeFrame: 6 weeks postoperatively
measure: Changes in Axial Length (measured by biometry, in milimeters)
timeFrame: 6 weeks postoperatively
measure: Changes in corneal curvature (measured by corneal topography, in diopters)
timeFrame: 6 weeks postoperatively
Secondary outcomes:
Other outcomes:
Locations:
city: Sankt Gallen
country: Switzerland
facility: Cantonal Hospital of Sankt Gallen
Study officials:
References: