Measurement of Combined Corneal, Internal, and Total Ocular Optical Quality Analysis in Anterior Segment Pathology With the OPD-Scan and OPD-Station

Comparative analysis of the visual performance after implantation of the toric implantable collamer lens in stable keratoconus: a 4-year follow-up after sequential procedure (CXL+TICL implantation)

Aims

To report on 4-year postoperative visual performance with the toric implantable collamer lens (TICL) for stable keratoconus after sequential procedure (corneal collagen crosslinking plus TICL implantation).

Methods

Forty eyes of 24 patients with stable keratoconus with myopia between 0.00 and −18.00 dioptres (D) and astigmatism between 1.25 and 8.00 D were evaluated in this prospective interventional study (https://clinicaltrials.gov/ct2/show/NCT02833649). We evaluated refraction, visual outcomes, astigmatic changes analysed by Alpins vector, contrast sensitivity, aberrometry, modulation transfer functions (MTFs), defocus curve, and operative and postoperative complications.

Results

At 4-year follow-up, 45% had 20/20 vision or better and 100% had 20/40 or better uncorrected visual acuity (UCVA). Vector analysis of refractive astigmatism shows that the surgically induced astigmatism (SIA) (3.20±1.46 D) was not significantly different from the target induced astigmatism (TIA) (3.14±1.42 D) (p=0.620). At 4 years postoperatively, none of the eyes showed a decrease in UCVA, in contrast to 24 eyes in which UCVA was increased by ≥1 lines, with contrast sensitivity and improvement in total aberrations and MTF value at 5 per degree (*p=0.004) after TICL implantation. The cumulative 4-year corneal endothelial cell loss was ≤5%. No patients reported dissatisfaction. At the end of follow-up, the vault was 658±54.33m (range, 500–711) and the intraocular pressure was 11.7±2.08 mm Hg. Occurrences of glare and night-driving troubles diminished after TICL surgery.

Conclusion

The results from this standardised clinical investigation support TICL implantation from clinical and optical viewpoints in patients with stable keratoconus.

Trial registration number

NCT02833649, Pre-results

Simple and accurate alignment of toric intraocular lenses and evaluation of their rotation errors using anterior segment optical coherence tomography

PURPOSE

To describe a new method of alignment of toric intraocular lenses (IOLs) and evaluation of their rotation errors using anterior segment optical coherence tomography (AS-OCT).

METHODS

Twenty-nine eyes of 22 patients who had cataract extraction and implantation of an acrylic toric IOL were included. The new AS-OCT method was used for the alignment of toric IOLs and evaluation of their rotation errors. These rotation errors were evaluated and compared with those measured using the internal map of a wavefront aberrometer.

RESULTS

The mean rotation error ± standard deviation (SD) of the toric IOLs evaluated by AS-OCT was 3.2 ± 2.2° and 3.2 ± 2.4° at 1 week and 1 month after surgery, respectively. The mean difference in the reference axis between the visits was 1.8 ± 2.1°. The mean difference between the rotation errors of the alignment axes measured by AS-OCT and the internal map was 2.5 ± 1.9° (P = 0.037).

CONCLUSION

The current method is clinically useful not only for the accurate alignment of toric IOLs but also for evaluating their rotation errors.

Intrasubject repeatability of internal aberrometry obtained with a new integrated aberrometer

PURPOSE

To evaluate the intrasubject repeatability of the internal aberrometry obtained with a new integrated aberrometer in a sample of normal eyes to assess its clinical usefulness.

METHODS

Twenty-six healthy eyes of 26 participants, aged 20 to 50 years, were included in the study. All eyes achieved corrected distance visual acuity of 1.0 (Snellen decimal notation) and did not undergo previous ocular surgeries. Three consecutive measurements of internal aberrations were obtained with the KR-1W system (Topcon Corp) by an experienced examiner. Intrasubject repeatability for 4- and 6-mm pupils was evaluated by the within-subject standard deviation (S(w)) and intraclass correlation coefficient (ICC).

RESULTS

Low values of S(w) and values of ICC close to 1 were found for the 4-mm pupil astigmatism and for several aberrometric coefficients: primary spherical aberration and higher order, third order, and trefoil root-mean-square (RMS). Significant correlations of the S(w) for the 4-mm pupil higher order aberrations RMS with the magnitude of different aberrometric coefficients were found (r≥0.611, P<.01). In addition, tetrafoil RMS for 4-mm pupils correlated significantly with the S(w) for some higher order errors (r≥0.675, P<.01). Significantly larger values of S(w) for 6-mm pupils were found for trefoil (P<.01) and secondary astigmatism RMS (P=.02).

CONCLUSIONS

The KR-1W provided repeatable measurements of internal astigmatism and some higher order aberrations, although consistency of such measurements appears to be limited by the level of aberration.

Visual and optical performance before and after rotation of a misaligned STAAR Toric Implantable Collamer Lens

PURPOSE

To document the use of the NIDEK OPD-Scan II/Station as a monitoring tool and clinical aid in the evaluation and re-rotation of a misaligned STAAR Toric Implantable Collamer Lens (TICL).

METHODS

A 22-year-old man underwent bilateral TICL implantation. Emmetropia was achieved in the left eye after TICL implantation; however, the right eye showed residual compound myopic astigmatism. Both eyes were evaluated using the OPD-Scan II/Station, and re-rotation of the TICL in the right eye was planned using the internal wavefront and corneal topography maps. The remaining residual error after re-rotation was treated using photorefractive keratectomy (PRK).

RESULTS

The left eye showed excellent axis alignment and optical quality. The right eye showed a difference of 8 degrees to 10 degrees in axis of orientation and an under-calculation of the lens power, which resulted in poor optical quality. After rotation of the lens and PRK, emmetropia was achieved and the patient reported resolution of symptoms. Higher order aberrations were reduced by 0.535 microm and the modulation transfer function increased 42% compared to initial TICL implantation.

CONCLUSIONS

Internal and corneal surface aberrometry allowed proper evaluation and precise realignment of a TICL. The objective assessment of the internal astigmatism, optical quality, and visual performance aids in planning complicated surgical cases that require combination surgery to restore visual quality.

Axis alignment and rotational stability after implantation of the toric implantable collamer lens for myopic astigmatism

PURPOSE

To assess axis alignment and stability of the Toric Implantable Collamer Lens (TICL; STAAR Surgical Co) over time.

METHODS

Thirty-five consecutive eyes of 19 patients received the TICL for treatment of myopic astigmatism. Manifest refraction spherical equivalent (MRSE) and manifest refractive cylinder were measured preoperatively and at 3 months postoperatively. The axis alignment of the TICL was measured using the internal OPD map obtained with the OPD-Scan II (NIDEK Co Ltd).

RESULTS

Mean refractive cylinder was reduced from 2.80+/-1.45 diopters (D) preoperatively to 0.63+/-0.75 D at 3 months postoperatively; MRSE was -7.61+/-4.02 D preoperatively and -0.14+/-0.38 D at 3 months. Mean absolute value of the measured axis misalignment from baseline (day 1) to 1 month was 2.90+/-2.11 degrees and from 1 month to 3 months was 4.6+/-11.2 degrees. Mean absolute value of the measured changes in axis misalignment from baseline to 3 months was 2.68+/-2.11 degrees (after excluding one eye that required repositioning due to TICL rotation). At 3 months postoperatively, 96.8% (30/31) eyes had <or=8 degrees and 90.3% (28/31) had <or=5 degrees of axis misalignment.

CONCLUSIONS

The TICL showed minimal axis misalignment after implantation and remained stable 3 months postoperatively.

Objective and subjective preoperative refraction techniques for wavefront-optimized and wavefront-guided laser in situ keratomileusis

PURPOSE

To determine which of 3 methods for measuring preoperative refractive error yields the best refractive outcomes after wavefront-guided (Visx Star S4) or wavefront-optimized (WaveLight Allegretto Wave) excimer laser in situ keratomileusis (LASIK).

SETTING

Emory Eye Center and Emory Vision, Emory University, Atlanta, Georgia, USA.

METHODS

This retrospective analysis of LASIK, performed from June to December 2007, analyzed sphere, cylinder, and spherical equivalent (SE) refractions generated from 3 methods (manifest refraction, aberrometer autorefraction [CustomVue WaveScan], corneal analyzer autorefraction [Nidek ARK-10000 OPD]), actual programmed treatment, and absolute deviation from ideal treatment (deviation) for each technique.

RESULTS

In the wavefront-guided group (63 eyes, 33 patients), manifest refraction and aberrometer autorefraction generated similar deviation for sphere and SE; both were significantly better than corneal analyzer autorefraction (P= .02 and P= .03, respectively). Aberrometer autorefraction generated less cylinder deviation than the other methods (both P= .003). In the wavefront-optimized group (61 eyes, 36 patients), manifest refraction generated less deviation for sphere and SE than aberrometer autorefraction or corneal analyzer autorefraction (sphere: P= .005 and P= .009, respectively; SE: P= .005 and P= .002, respectively). Manifest refraction and aberrometer autorefraction cylinder generated similar deviation, while aberrometer autorefraction was less than corneal analyzer autorefraction (P= .041).

CONCLUSIONS

Overall, manifest refraction was most accurate in generating postoperative emmetropia with both laser treatments; however, aberrometer autorefraction produced the least cylinder deviation for wavefront-guided treatment. Corneal analyzer autorefraction produced the least accurate results with both lasers.