#Itrace toric lens alignment manual#

The visual acuity was converted to the logarithm of the minimum angle of resolution.

Uncorrected distance visual acuity (UDVA) and best-corrected visual acuity (BCVA) were recorded before and after surgery. The study complied with the principles laid down in the Declaration of Helsinki and was approved by the Ethics Committee of Guangdong Provincial People’s Hospital. Written informed consent was obtained from the patients. Randomization was performed using computerized random number tables. Patients and MethodsĪll patients were randomly divided into the TRP marking group (15 eyes) and slit-lamp horizontal meridian (SHM) marking group (15 eyes). The aim of this study was to introduce the three-random-point (TRP) marking method performed using the iTrace system (Tracey Technologies Corp. However, using a digital image-guidance system has disadvantages of high cost and need for special equipment.

#Itrace toric lens alignment manual#

A digital image-guidance system used during toric IOL surgery is more reliable and precise than manual marking. Accurate preoperative marking of the eye with the patient in the sitting position can minimize the intraoperative misalignment errors. All manual methods for corneal marking can cause errors. Manual methods for horizontal meridian limbal marking were commonly used preoperatively, including the slit-lamp marking, surgeon’s direct visual marking, bubble marker-assisted method, pendular marker-assisted method, and tonometer marking. The average cyclotorsion of the eye when the patient is changed from the upright position to the supine position is approximately 2°–4° but can be up to 15°. When the patient is changed from the standing or sitting position to the supine position, cyclotorsion of the eye can cause misalignment. Precise preoperative limbal marking is crucial for an accurate alignment of toric IOLs. Toric intraocular lens (IOL) implantation during cataract surgery was more widely used owing to its reliability and effectiveness. Several surgical techniques, such as limbal relaxing incisions, peripheral corneal relaxing incisions, and excimer laser surgery, are used to eliminate or decrease coexisting astigmatism in patients with cataract. Because persisting astigmatism can decrease the visual acuity and the vision quality of patients after cataract surgery, predictable correction of the preexisting corneal astigmatism is critical and popular. It has been estimated that 30% of patients with cataract have preexisting astigmatism of over 0.75 D 8% of the eyes have corneal astigmatism of over 2.00 D and 2.6% of the eyes have corneal astigmatism of over 3.00 D. It can eliminate the potential systematic errors resulting from varying head positions during the preoperative keratometry measurement and from manual marking. The TRP marking method using the iTrace aberrometer is simple and accurate for preoperative marking of toric IOLs. The mean toric IOL misalignment was lesser but without significance in the TRP marking group than in the SHM marking group after 3 postoperative months (2.66° ± 1.42° versus 3.29° ± 1.67° ). There was no statistically significant difference in BCVA, UDVA, preexisting corneal astigmatism, or residual astigmatism between the groups before or after surgery. Fifteen eyes of 15 patients were in the TRP marking group and 15 eyes of 15 patients in the SHM marking group. The follow-up duration was 3 months after cataract surgery. TRP marking involved marking three points randomly in the corneal limbus of the patients and accurately marking the horizontal meridian was not required. All patients were prospectively randomized into the TRP marking group or slit-lamp horizontal meridian (SHM) marking group.

Thirty eyes of 30 patients undergoing cataract surgery with coexisting corneal astigmatism of over 1.0 D were included in this study. Prospective, randomized comparative trial. Department of Ophthalmology, Guangdong Eye Institute, Guangdong Academy of Medical Sciences, Guangdong Provincial People’s Hospital, Guangzhou, China. To evaluate the clinical outcome of the three-random-point (TRP) marking method for toric intraocular lens (IOL) alignment using the iTrace aberrometer (Tracey Technologies Corp., Houston, TX).