verion versus conventional, manual ink-marking in toric iol implantation

Conditions: Astigmatism

Summary: overview cataract is a clouding of the crystalline lens which causes vision loss and blindness if untreated. cataract surgery is the most frequently performed surgical intervention in medicine with an incidence of 880 surgeries per 100.000 population in 2010 amounting to a total number of over 160.000 surgeries per year in the netherlands. approximately 22% of patients with cataract have a substantial pre-existing corneal astigmatism. toric iols provide the opportunity to correct pre-existing astigmatism, offering the patients optimum distance vision without the use of spectacles or contact lenses. toric iols are increasingly used in cataract and refractive surgery. since the introduction of toric intraocular lenses (iols) in the treatment of cataract in patients with pre-existing corneal astigmatism, numerous studies have shown the importance of accurate positioning of the toric iol to the intended alignment axis. an error of 5º in toric iol alignment will decrease the anticipated effect by 17% and thus misalignment will decrease the effectiveness of the astigmatism treatment. there are several methods used to align the toric iol at the intended axis. most of these use a 3-step ink-marking procedure and are performed manually. clinical study showed an average error of 5º in toric iol alignment when using this method. two new tools that have recently been introduced to the market are the verion measurement module and verion digital marker. together, these tools provide integrated digital guidance for alignment of toric iols and they have the potential to eliminate the error in horizontal axis marking and the alignment axis marking error. this will lead to an improved visual outcome. so far, there are no published studies using the verion tools for toric iol alignment in cataract surgery. therefore, the investigators will perform this randomized control trial. main hypothesis the investigators hypothesise that cataract surgery with the implantation of a toric iol, when using the verion-tools, compared to manual ink-marking, in patients with corneal astigmatism will lead to: - an increase in accuracy in toric iol alignment objectives primary objective: the primary objective of the study is to compare the accuracy in toric iol alignment when using the verion-tools for alignment of the toric iol or the conventional manual ink-marking procedure. other hypotheses and objectives are available in the detailed description.

extra hypotheses * a decrease in residual astigmatism * an improved best corrected distance visual acuity (bcva) * an improved uncorrected distance visual acuity (ucva) * a decrease in residual refractive astigmatism * a decrease or comparable complication profile secondary objective: the secondary objective of the study is to compare residual astigmatism when using the verion measurement module and verion digital marker for alignment of the toric iol or the conventional manual ink-marking procedure. other secondary objectives: the other secondary objectives are to compare: 1. best corrected distance visual acuity (bcva) 2. uncorrected distance visual acuity (ucva) 3. residual refractive astigmatism 4. wavefront aberrations 5. complication profile

Eligibility criteria:
inclusion criteria: * astigmatism (at least 1.25d) * cataract * are at least 18 years of age * eye eligible to undergo cataract extraction * eye eligible for toric iol implantation * bilateral eyes: availability to undergo second eye surgery within 2 weeks of the first eye surgery * willing and able to comply with scheduled visits and other study procedures * understand and signed informed consent exclusion criteria: * irregular corneal astigmatism or keratoconus * extensive age related macular degeneration (atrophic or exudative amd or numerous soft drusen) * fuchs endothelial dystrophy (stage 2) * uncontrolled/manifest glaucoma * glaucoma related extensive visual field loss * extensive diabetic macular disease * previous intraocular or corneal surgery of any kind * subjects presenting any contraindications to cataract surgery * subjects with a recurrent or active ocular or uncontrolled eyelid disease * subjects with a history of lens instability (e.g. posterior polar cataract, traumatic cataract) or zonular instability

Keywords: toric iol alignment verion digital marker manual ink-marking randomized controlled trial