Long Term Evaluation of Surgically Induced Astigmatism and Corneal Higher-Order Aberrations After 2.2 Mm Clear Corneal Incisions in Femtosecond Laser-Assisted Cataract Surgery: Temporal versus Superior Approach

Purpose

To assess long term changes of the surgically induced astigmatism (SIA) and corneal higher-order aberrations (HOAs) after 2.2 mm clear corneal incisions (CCIs) in femtosecond laser-assisted cataract surgery and compare them between 2 types of CCIs: temporal and superior approach.

Patients and Methods

Patients received the temporal CCIs (Group A) or the superior CCIs (Group B). Outcome measures included visual acuity, manifest refraction, corneal astigmatism, SIA, flattening effect, and corneal HOAs. Correlation between postoperative corneal HOA and SIA at each follow-up were analysed.

Results

This study assessed data from 106 eyes, of which 64 in Group A and 42 in Group B. The two groups had similar postoperative visual acuity of distance, intermediate and near (all P > 0.05). SIA and corneal HOAs were significantly lower in Group A than Group B in the early postoperative period, while there was no significant difference in the late postoperative period. At 6 months after surgery, the arithmetic mean of SIA over corneal 4mm zone was 0.33 ± 0.19D for temporal incision, and 0.37 ± 0.25D for superior incision. For Group A, the correlations of HOAs and SIA persisted from 1 week to 6 months after surgery. For Group B, the changes in corneal HOAs were significantly related to the SIA at 1 week and 1 month postoperatively.

Conclusion

This study suggested the consistency of increasing and recovering process of corneal HOAs and SIA after surgery. Compared to the superior incisions, temporal incisions might induce quicker corneal recovery and less change in SIA and corneal HOAs.

Comparative Analysis of Corneal Higher-Order Aberrations after Laser-Assisted In Situ Keratomileusis, Photorefractive Keratectomy, and Small Incision Lenticule Extraction with Correlations to Change in Myopic Q-Value and Spherical Equivalent with and without Astigmatism

Background: This retrospective chart review compared the higher-order aberrations (HOAs) among photorefractive keratectomy (PRK), laser-assisted in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE) alongside changes in spherical equivalent (SEQ) and corneal shape (Q-value). Methods: Analyzing 371 myopic eyes, including 154 LASIK, 173 PRK, and 44 SMILE cases, Pentacam imaging was utilized pre-operatively and at one-year post-operative visits. Results: All procedures resulted in 100% of patients achieving an uncorrected distance visual acuity (UDVA) of 20/40 or better, with 87% of LASIK and PRK, and 91% of SMILE patients having 20/20 or better. Significant increases in HOAs were observed across all procedures (p < 0.05), correlating positively with SEQ and Q-value changes (LASIK (0.686, p < 0.05), followed by PRK (0.4503, p < 0.05), and SMILE (0.386, p < 0.05)). Vertical coma and spherical aberration (SA) were the primary factors for heightened aberration magnitude among the procedures (p < 0.05), with the largest contribution in SMILE, which is likely attributed to the centration at the corneal apex. Notably, PRK showed insignificant changes in vertical coma (-0.197 µm ± 0.0168 to -0.192 µm ± 0.0198, p = 0.78), with an increase in oblique trefoil (p < 0.05). Conclusions: These findings underscore differences in HOAs among PRK, LASIK, and SMILE, helping to guide clinicians.

Fourier analysis of corneal irregular astigmatism after small-incision lenticule extraction and transepithelial photorefractive keratectomy: A comparative study

To compare changes in the spherical component, regular astigmatism, and irregular astigmatism of the anterior surface of the cornea after small-incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (TransPRK). Fifty-six patients underwent SMILE in 56 eyes, and 68 patients underwet TransPRK in 68 eyes. The right eye was chosen to enter the group. Six months after the procedure, Scheimpflug images were acquired, and Fourier analysis of the anterior surface of patients' corneas was performed using the Pentacam built-in software. Fourier parameters encompass various measurements such as the steepest radius of the curvature and average eccentricity of the spherical components (SphRmin and SphEcc), maximum decentration (MaxDec), central and peripheral regular astigmatism (regular astigmatism at the center [AstC] and regular astigmatism at the periphery [AstP]), and irregularity (Irr). At 6 months postoperatively, SphEcc decreased significantly (P < .001), MaxDec increased significantly (P < .001), and Irr increased insignificantly (P = .254) in the SMILE group. SphEcc decreased significantly (P < .001) and MaxDec and Irr increased significantly (P < .001) in the TransPRK group. TransPRK caused greater changes in SphEcc, MaxDec, and Irr on the anterior corneal surface than SMILE (P < .05). The amount of MaxDec-induced changes in SMILE and TransPRK was significantly correlated with the amount of higher-order aberrations and spherical aberration changes (P < .05). SMILE and TransPRK increase overall irregular astigmatism on the anterior surface of the cornea, more so with TransPRK, where changes in decentration are associated with with increased higher-order aberrations.

International Multicenter, Myopic and Myopic Astigmatism Femto LASIK, Customized by Automated Ray-Tracing Ablation Profile Calculation: A Postmarket Study

Purpose

To assess the safety and efficacy of a customized ablation treatment (InnovEyes) to correct myopia and myopic astigmatism with femtosecond laser-assisted in situ keratomileusis (Femto LASIK).

Patients and Methods

In this prospective, nonrandomized, multicenter study, 113 patients (225 eyes) with preoperative myopia less than -9.0 diopters (D) and astigmatism 0 to -4.0 D (based on InnovEyes refraction) underwent wavefront, tomography, and biometry assessment using a single diagnostic device (InnovEyes sightmap). These data were imported and used unmodified by the InnovEyes algorithm to automatically calculate and optimize correction of lower- and higher‑order aberrations (HOAs) treated by the EX500 ablation profile. Visual acuity, refractive error, HOAs, and patient satisfaction were evaluated over 3 months.

Results

A total of 106 patients (212 eyes) completed the study and were included in the analysis. Mean preoperative manifest refraction spherical equivalent (MRSE) was -3.38±1.76 D. At Month 3, uncorrected distance visual acuity was 20/20 or better in 208/212 (98.1%) eyes, and it was the same as, or better than, the preoperative best-corrected distance visual acuity (CDVA) in 162/212 (76.4%) eyes; 76/212 (35.8%) eyes gained ≥1 line of CDVA. MRSE was within ±0.5 D in 195/212 (92.0%) eyes. Additionally, 201/209 (96.2%) eyes had no change (defined as a change between -0.1 μm and 0.1 μm, inclusive) in HOAs, and 105/106 (99.1%) patients reported to be satisfied with the results.

Conclusion

Customizing ray-tracing Femto LASIK with this platform appeared safe and effective in correcting myopic astigmatism and also achieved a significant percentage of eyes gaining lines of vision, potentially by addressing HOAs, along with a consistently high level of patient satisfaction.

Symmetrical femtosecond laser arc incision in correcting corneal astigmatism in cataract patients

AIM

To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laser-assisted phacoemulsification (FLACS).

METHODS

This study enrolled patients with cataract combined with regular corneal astigmatism of >0.75 D, who underwent FLACS. Symmetrical arc incision was set at 8 mm diameter and 85% depth. The follow-up time was 3-24mo (4.92±3.49mo). Pentacam recorded the corneal astigmatism and higher-order aberration at pre-operation and post-operation. The changes in corneal astigmatism were analyzed by Alpins method. The correlation of astigmatism type, age, corneal horizontal diameter, corneal thickness, arc incision length, and correction index (CI) was analyzed, and the residual corneal astigmatism was compared with the residual whole eye astigmatism.

RESULTS

Totally 79 patients (102 eyes) were enrolled, 10 patients had corneal epithelial injury, 1 patient occurred corneal epithelial hyperplasia. The corneal astigmatism was 1.23±0.38 D pre-operation, and decreased to 0.76±0.39 D post-operation (t=10.146, P=0.000). Corneal high-order aberration was 0.17±0.08 µm pre-operation and 0.24±0.11 µm post-operation (t=-5.186, P=0.000). The residual corneal astigmatism and residual whole eye astigmatism were no significant difference (t=-0.347, P=0.729). Using Alpin's method, the following were determined: target-induced astigmatism (TIA) =1.23±0.38 D, surgery-induced astigmatism (SIA) =0.77±0.45 D, difference vector (DV)=0.77±0.39 D, and CI=0.54±0.28. Age, astigmatism size, corneal horizontal diameter, corneal thickness, and arc incision length were not correlated with CI. The CI for against the rule astigmatism (ATR) was better than that for with the rule astigmatism (WTR; P=0.001).

CONCLUSION

Femtosecond laser-assisted astigmatic keratotomy has better CI of ATR, but increase higher-order corneal aberration. CI is not ideal, it's not a perfect choice if we pursue ideal correction effect.

Association between Corneal Higher-Order Aberrations Evaluated with a Videokeratographer and Corneal Surface Abnormalities in Dry Eye

Analysis of higher-order aberrations (HOAs) is one reported method for evaluating dry eye disease (DED)-related loss of visual function. Tear film (TF) instability and corneal epithelial damage (CED) are both reportedly responsible for HOAs in DED, although, to the best of our knowledge, there are no reported methods that allow concurrent evaluation of their effects. In this study, we used a videokeratographer (VK) to continuously measure HOAs in DED after eye opening and investigated factors of ocular surface abnormalities that determine HOAs. This study involved 96 DED cases that underwent DED symptom assessment with a questionnaire and examination of tear volume, TF abnormalities (i.e., TF lipid-layer interference grades and spreading grades, and non-invasive breakup time and fluorescein breakup time), and CED, and their correlation with HOAs evaluated via VK. The results show that HOAs at 1 or 2 s after eye opening can reflect TF instability and CED within the central 4-millimeter-diameter area of the optical zone in DED eyes concurrently. This finding may be useful for the rapid and non-invasive detection and evaluation of degraded visual function in DED cases with a variety of clinical features.

A Prospective Study of Cyclosporine A 0.1% Combined with Loteprednol 0.2% vs Cyclosporine A 0.05% Alone in the Treatment of Dry Eye

PURPOSE

To examine the efficacy and tolerability of a combination of cyclosporine 0.1% and loteprednol 0.2% (CsA-LE; Klarity CL) in comparison to commercially available cyclosporine 0.05% (CsA; Restasis) in improving signs and symptoms of dry eye.

METHODS

This multicenter, prospective, randomized, controlled, open-label study evaluated 60 patients randomized to a single treatment for 4 weeks and evaluated at day 0, day 14, and day 28. Comparison was made of corneal higher-order aberrations (HOAs), dry-eye symptoms (SPEED score), tear-breakup time (TBUT), corneal staining, and ocular hyperemia, as well as tolerability of each medication with the validated COMTOL instrument.

RESULTS

A total of 56 patients completed enrollment. Corneal HOAs improved significantly with CsA-LE, but not CsA alone. Both groups showed significant improvement (with no significant differences between groups) in SPEED scores, corneal staining, TBUT, and conjunctival hyperemia. Tolerability was similar between the drugs, and no significant safety issues were identified.

CONCLUSION

The combination of CsA 0.1%-LE 0.2% provided significant improvement in corneal HOAs, while CsA 0.05% did not. For all other measures of ocular surface improvement, both medications showed similar benefits. Tolerability was comparable between the formulations. When rapid rehabilitation of the ocular surface is needed to reduce aberrations, CsA-LE is an appropriate choice.

A Novel Procedure for Keratoconus/Corneal Ectasia Treating Epithelial Compensation of Higher-Order Aberrations, Topographic Guided Ablation, and Corneal Cross Linking - The CREATE+CXL Protocol

Purpose

To present the outcomes of a retrospective study in keratoconus/corneal ectasia patients of treating the higher order aberrations compensated for the corneal epithelium in addition to topographic guided ablation followed by corneal cross linking.

Methods

Twenty-seven eyes of 14 patients were treated for keratoconus/corneal ectasia utilizing trans-epithelial topographic guided ablation photorefractive keratectomy (PRK) for treatment of corneal higher order aberrations and lower order astigmatism followed immediately by 15-minute cross linking were examined retrospectively. Six-month results were analyzed via measurement of vision, refraction, residual higher-order aberrations (HOAs), residual lower-order and higher-order aberrations, as well as for loss or gains of lines of best corrected visual acuity.

Results

All eyes save one had reduction in K1, K2, K Max, and K Mean. All eyes had reduction in manifest astigmatism, Contoura measured astigmatism, 57% reduction of higher-order aberrations (HOA), and 53% reduction of higher-order aberrations grouped with lower-order aberrations (Grouped). Nearly all (96.3%) eyes achieved 20/40 vision or better, 20 eyes had 1-7 lines gained of vision, and no eyes had any loss of lines of vision.

Conclusion

Use of the CREATE+CXL protocol combined with 15-minute corneal cross linking results in a significant increase in HOA reduction, as well as a significant improvement in corrected distance visual acuity over past procedures.

Efficacy of custom-made soft keratoconus lenses on corneal aberrations and photic phenomena in patients with keratoconus: a corneal topography imaging based study

AIM

To evaluate the efficacy of custom-made soft keratoconus (KC) lenses on corneal aberrations and photic phenomena in two different optical zones in patients with KC.

METHODS

Sixty eyes of 42 patients with KC were examined at baseline and after fitting HydroCone (Toris K) soft silicone hydrogel lenses. Best spectacle-corrected visual acuity (BSCVA) and contact lens-corrected visual acuity (CLCVA) were recorded. Lower- and higher-order corneal aberrations (LOAs and HOAs) were measured with and without Toris K lenses and compared in central 4.5 mm and 7 mm zones. Mesopic pupil diameter and subjective photic phenomena were also assessed.

RESULTS

Mean CLCVA was significantly improved compared to BSCVA (P<0.0001). Corneal curvature and refractive measurements were found to be significantly reduced by the use of Toris K lenses, except for posterior corneal curvature values. In the 4.5 mm central optical zone, all wavefront aberrations decreased significantly after lens fitting (P<0.0001). In contrast, in the 7 mm (peripheral) optical zone, values for HOAs, spherical and residual aberrations, and optical path differences were increased, while LOAs, trefoil, and quadrifoil coefficients were decreased. The rate of photic phenomena was significantly higher in participants with a pupil size >6.00 mm (85.7%).

CONCLUSION

Toris K lenses provide good visual results and a significant reduction in central corneal aberrations in patients with KC but could cause an increase in peripheral aberrations. This practical and nonsurgical approach appears to be an effective method for the visual management of KC.

Orthokeratology with increased compression factor in adolescent myopia control: a 2-year prospective randomized clinical trial

AIM

To explore the long-term efficacy, safety, and optical mechanism of orthokeratology with increased compression factor in adolescent myopia control.

METHODS

A prospective, double-masked, and randomized clinical trial was performed from May 2016 to June 2020. Subjects aged between 8 and 16y, with myopia (-5.00 to -1.00 D), low astigmatism (≥-1.50 D) and anisometropia (≤1.00 D), were stratified into low (-2.75 to -1.00 D) and moderate (-5.00 to -3.00 D) myopia groups. Then they were randomly assigned to wear either increased compression factor (ICF; 1.75 D) orthokeratology or conventional compression factor (CCF; 0.75 D) orthokeratology. The data were recorded including axial length (AL), spherical equivalent (SE), best corrected visual acuity (BCVA), near visual acuity (NVA), corneal staining (using Efron grading scales), corneal hysteresis (CH), corneal resistance factor (CRF), higher-order aberrations (HOAs, expressed as root mean square, RMS_h), and subfoveal choroidal thickness (SFChT) in the 2-year follow-up period. Pearson's correlation coefficient was conducted to analyze the association between the changes in AL and RMS_h, SFChT.

RESULTS

At the 2-year visit, there were no statistical differences in all the parameters between the ICF group and the CCF group in low myopia subjects (P>0.05). For the moderate myopia subjects, the ICF group had shorter AL elongation (0.23±0.08 vs 0.30±0.11 mm, P=0.015), higher RMS_h (1.94±0.50 vs 1.65±0.51 µm, P=0.041), and higher SFChT (279.04±35.72 vs 254.08±29.60 µm, P=0.008) than those in CCF group. The change in AL was negatively correlated with RMS_h (r=-0.687, P<0.001) and SFChT (r=-0.464, P=0.013).

CONCLUSION

ICF orthokeratology can control the progression of moderate myopia more effectively, which might be related to greater RMS_h and SFChT.

Scheimpflug-Derived Corneal Lower and Higher Order Aberrations Post Intrastromal Corneal Ring Segments for Keratoconus

Intrastromal corneal ring segments (ICRS) improve corneal topographic symmetry and reduce corneal aberrations through regularization of the corneal surface, thereby functioning as a viable surgical intervention for patients with keratoconus. This study aims to evaluate changes in lower- (LOAs) and higher-order aberrations (HOAs) amongst varying pupil sizes pre- and post- ICRS implantation in keratoconus patients. We specifically investigate the impact of pupil size on total corneal HOAs up to the 6th order. Twenty-one eyes that underwent ICRS implantation were included in this prospective interventional study. LOAs and HOAs measurements at the 6 mm, 4 mm, and 2 mm pupil diameters were collected preoperatively and at 6 months postoperatively using the Zernicke analysis function on a Scheimpflug device. ICRS implantation demonstrated a statistically significant effect in vertical coma with a −0.23 reduction (p = 0.015) for a 4 mm pupil size and a −1.384 reduction (p < 0.001) for 6 mm, with no significant effect at 2 mm. Horizontal coma, astigmatism 0°, astigmatism 45°, trefoil 5th order 30°, and RMS HOA demonstrated significant reductions at 4 mm or 6 mm pupil sizes but not at 2 mm. Our analysis demonstrates a favorable effect of ICRS implantation on larger pupil sizes, suggesting the importance of pupil size as it correlates with HOAs reduction.

Evaluation of Anterior and Posterior Corneal Higher Order Aberrations for the Detection of Keratoconus and Suspect Keratoconus

AIM

To investigate the application of anterior and posterior corneal higher-order aberrations (HOAs) in detecting keratoconus (KC) and suspect keratoconus (SKC).

METHOD

A retrospective, case-control study evaluating non-ectatic (normal) eyes, SKC eyes, and KC eyes. The Sirius Scheimpfug (CSO, Italy) analyses was used to measure HOAs of the anterior and posterior corneal surfaces. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated.

RESULTS

Two-hundred and twenty eyes were included in the analysis (normal n = 108, SKC n = 42, KC n = 70). Receiver operating characteristic (ROC) curve analysis revealed a high predictive ability for anterior corneal HOAs parameters: the root mean square (RMS) total corneal HOAs, RMS trefoil, and RMS coma to detect keratoconus (AUC > 0.9 for all). RMS Coma (3, ±1) derived from the anterior corneal surface was the parameter with the highest ability to discriminate between suspect keratoconus and normal eyes (AUC = 0.922; cut-off > 0.2). All posterior corneal HOAs parameters were unsatisfactory in discriminating between SKC and normal eyes (AUC < 0.8 for all). However, their ability to detect KC was excellent with AUC of >0.9 for all except RMS spherical aberrations (AUC = 0.846).

CONCLUSIONS

Anterior and posterior corneal higher-order aberrations can differentiate between keratoconus and normal eyes, with a high level of certainty. In suspect keratoconus disease, however, only anterior corneal HOAs, and in particular coma-like aberrations, are of value. Corneal aberrometry may be of value in screening for keratoconus in populations with a high prevalence of the disease.

Evaluating early-stage disk halo changes after small incision lenticule extraction

PURPOSE

To investigate early changes in the disk halo under different light conditions after myopic small incision lenticule extraction (SMILE).

METHODS

This prospective study included 70 eyes of 70 myopic patients aged 18-33 years, with a spherical equivalent (SE) of -5.87 ± 1.86 D, who underwent SMILE. The subjective refraction, higher-order aberrations (HOAs), pupillometry, and halo were measured preoperatively and postoperatively to analyse disk halo variations and correlated factors.

RESULTS

At 5 cd/m2 and 1 cd/m2 luminance, the halo radius in the high myopia (HM) group reached a postoperative peak after 1 week (p = 0.000 and 0.019, respectively), and recovered to baseline after 3 months. In the low-to-moderate (LM) myopia group, the halo radius did not differ 1 week postoperatively compared to the preoperative level (p = 0.015), but significantly improved after 3 months (p = 0.000). The halo radius correlated with SE, uncorrected distance visual acuity (UDVA), ocular HOAs, coma, and the pupillary light reflex in the LM group at all time points, but there were no correlations in the HM group.

CONCLUSIONS

Halo symptoms occurred early after SMILE, but recovered within 3 months. The recovery process was slower in the HM group than in the LM group, and the halo radius correlated with SE, UDVA, ocular HOAs, coma, and the pupillary light reflex.

Combined corneal wavefront-guided transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking following intracorneal ring segment implantation in management of moderate keratoconus

PURPOSE

Keratoconus (KC) leads to gradual progressive loss of vision in young and adult patients. For the purpose of visual rehabilitation and for hindering KC progression in patients, we designed this study. The main aim of this study is to help the KC patients to improve and stabilize their vision.

METHODS

This prospective consecutive uncontrolled study includes 36 eyes of 36 patients with moderate degree of KC. All patients underwent combined wavefront-guided transepithelial photorefractive keratectomy (TPRK) and accelerated corneal collagen cross-linking (ACXL) after intracorneal ring segment (ICRS) implantation. Different measures will be evaluated at baseline, after ICRS implantation, and at one, 3, 6, and 12 months after combined (TPRK and ACXL). These measurements are uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, and higher-order aberrations (HOAs) based on (Sirius, Schwind) tomography.

RESULTS

There were significant improvements in logMAR (UDVA and CDVA) and reduction in sphere, manifest cylinder, MRSE, maximal keratometry, and mean keratometry after ICRS implantation in the first stage. After TPRK and ACXL as the second stage, there were significant improvements in visual acuity of both logMAR UDVA and CDVA. Reduction in refractive outcomes, including MRSE, sphere, and manifest cylinder. All corneal indices including steep, flat, mean, and maximal keratometries had been decreased. Furthermore, there were significant improvements in the final root mean square, HOAs, and coma aberrations from baseline.

CONCLUSION

In moderate KC, triple therapy of ICRS implantation followed by combined TPRK and ACXL appears to be a safe and effective approach. This approach provides an improvement in visual acuity, refraction, corneal indices, and HOAs. These improvements were maintained for 1 year postoperatively. It also halts KC progression.

The Influence of Angle Alpha, Angle Kappa, and Optical Aberrations on Visual Outcomes after the Implantation of a High-Addition Trifocal IOL

The aim of our investigation was to examine the possible correlations between optical aberrations, angle kappa, angle alpha, and visual outcomes following cataract surgery. In total, 56 eyes of 28 patients were implanted with the Liberty 677MY trifocal intraocular lens (IOL). Pre- and postoperative higher-order aberrations, coma, astigmatism, angle alpha, and angle kappa were registered, along with uncorrected and corrected visual acuities at multiple distances. Visual acuity and contrast sensitivity defocus curves were plotted, and the areas under the curve were calculated 1 and 3 months postoperatively. Excellent visual outcomes were found at all distances. Patients reported low levels of dysphotopsia, and 96.4% of patients achieved complete spectacle independence. While angle kappa significantly decreased during cataract surgery (p = 0.0007), angle alpha remained unchanged (p = 0.5158). Angle alpha correlated with postoperative HOAs and had a negative impact on near vision (p = 0.0543). Preoperative corneal HOA and coma had a strong adverse effect on future intermediate and near vision. Residual astigmatism significantly affected postoperative intermediate vision (p = 0.0091). Our results suggest that angle kappa is not an optimal predictive factor for future visual outcomes, while angle alpha and the preoperative screening of optical aberrations might help patient selection prior to multifocal IOL implantation.

Comparison of small incision lenticule extraction and transepithelial photorefractive keratectomy in terms of visual quality in myopia patients

PURPOSE

To comprehensively compare visual quality between small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK).

METHODS

Sixty-four eyes in the SMILE group and 42 eyes in the tPRK group were enrolled in this study. In both groups, visual acuity, manifest refraction, higher-order aberrations (HOAs), contrast sensitivity (CS) at four spatial frequencies (3, 6, 12, 18 c/d) under three conditions (photopic, low glare, high glare), the cut-off value of the modulation transfer function (MTFcut-off), the objective scatter index (OSI) and the Strehl ratio (SR) were measured preoperatively and 1, 3 and 6 months postoperatively.

RESULTS

At 6 months postoperatively, the SMILE and tPRK groups showed similar safety, efficacy and predictability. Additionally, MTFcut-off, SR and OSI exhibited comparable results. In contrast, the photopic area under the logarithm of the CS function (AULCSF) showed better outcomes in the tPRK group than in the SMILE group (SMILE versus tPRK: 1.21 ± 0.10 versus 1.25 ± 0.09, p = 0.014). Furthermore, the induced coma aberrations were larger in the SMILE group (SMILE versus tPRK: 0.10 ± 0.16 versus 0.06 ± 0.12, 95% CI [0.08, 0.31], p < 0.0001).

CONCLUSIONS

Both SMILE and tPRK obtained comparable visual quality at 6 months postoperatively, accompanied by better photopic CS and smaller induced coma aberrations with tPRK. Paying more attention to alignment or developing a centration technique would be beneficial for visual quality when performing SMILE.

Effect of corneal incision features on anterior and posterior corneal astigmatism and higher-order aberrations after cataract surgery

PURPOSE

To evaluate the influence of 2.2 mm clear corneal incision (CCI) features in surgically induced astigmatism (SIA) and higher-order aberrations (HOAs) after cataract surgery.

METHODS

Right eyes of 92 subjects receiving 2.2 mm incision cataract surgery were involved. A total of 38 eyes were categorized as the intact incision group, and 54 eyes were the defective incision group. Pre- and postoperative (1 month and 6 months) corneal astigmatism and HOAs on anterior and posterior corneal surfaces, corneal volume, and corneal thickness (CT) were measured using Pentacam. The CCI features including incision length (IL), incision angles, distance from incision to central cornea (Dis-En/Ex), and CT at incision site were quantified using AS-OCT.

RESULTS

The defective incision group showed shorter IL and larger incision angles [false discovery rate (FDR) - p < 0.05]. Changes in CT at incision site were more pronounced for the defective incision group (FDR - p < 0.05). Some SIA parameters were related to the certain specific CCI features, especially IL (FDR - p < 0.05). Both groups exhibited significant increased 6 mm posterior corneal tHOAs at 1 month (Bonferroni corrected - p < 0.01) and the defective incision group showed increased 6 mm posterior tHOAs at 6 months (Bonferroni corrected - p = 0.023). There were characteristic correlations between Zernike terms and CCI features including IL, CT, Dis-En/Ex, and incision angles at 1 month, especially over 6 mm zone.

CONCLUSION

The CCI deformities can affect corneal recovery and induce more HOAs at 1 month postoperatively. Such effects became minor, but could persist until 6 months. The IL combined with Angle-En/Ex was important factor influencing CCI integrity and corneal optical quality.

Corneal Higher-Order Aberrations after Microhook ab Interno Trabeculotomy and Goniotomy with the Kahook Dual Blade: Preliminary Early 3-Month Results

We examined postoperative corneal higher-order aberrations (HOAs) present after combined phacoemulsification with either microhook ab interno trabeculotomy (μLOT-Phaco) or goniotomy, using the Kahook Dual Blade (KDB-Phaco). Retrospective study: A total of 45 eyes underwent μLOT-Phaco and KDB-Phaco (LOT-Phaco) procedures, with 21 eyes that underwent cataract surgery alone used as controls. Visual acuity and corneal HOAs, coma-like aberrations, and spherical-like aberrations were analyzed before and at 1, 2, and 3 months after the surgeries. Risk factors that could potentially influence HOAs were evaluated. No significant postoperative changes were noted for corneal HOAs, coma-like aberrations, and spherical-like aberrations after cataract surgery alone. The mean corneal HOAs, coma-like aberrations, and spherical-like aberrations were 0.222 ± 0.115 μm, 0.203 ± 0.113 μm, and 0.084 ± 0.043 μm at baseline and 0.326 ± 0.195 μm (p < 0.001), 0.302 ± 0.289 μm (p = 0.03), and 0.150 ± 0.115 μm (p < 0.001) at 3 months after LOT-Phaco, respectively. Results of the analysis for risk factors suggested that a longer incision in Schlemm’s canal could influence corneal HOAs, coma-like aberrations, and spherical-like aberrations after LOT-Phaco. Although no significant postoperative changes were observed in corneal HOAs and coma-like or spherical-like aberrations after cataract surgery alone, a significant increase in corneal HOAs and coma-like or spherical-like aberrations remained after the LOT-Phaco procedure.

Treatment of Keratoconus with WaveLight Contoura and Corneal Cross-Linking Combined

Purpose

To investigate the outcomes of the treatment of keratoconus/corneal ectasia utilizing topographic-guided ablation (WaveLight Contoura) followed by corneal cross-linking.

Methods

Thirty-six eyes of 21 patients were treated for keratoconus/corneal ectasia utilizing topographic guided ablation photorefractive keratectomy (PRK) for treatment of corneal higher-order aberrations and refractive error followed immediately by 15-minute cross-linking were examined retrospectively. Six-month results were analyzed via measurement of vision, refraction, residual higher-order aberrations (HOAs), residual lower-order and higher-order aberrations, as well as for loss or gains of lines of best-corrected visual acuity.

Results

All eyes save one had reduction in K1, K2, K Max, K Mean. All eyes had reduction in manifest astigmatism, Contoura-measured astigmatism, higher-order aberrations, higher-order aberrations grouped with lower-order aberrations (Grouped). Four eyes had lost 1-2 lines of vision, mainly to corneal haze formation, 17 eyes gained lines of vision, and 15 eyes equaled their pre-op best-corrected visual acuity. Eight eyes from four sample patients have their data included in this manuscript to demonstrate the procedure and the outcomes.

Conclusion

Treatment with WaveLight Contoura combined with 15-minute corneal cross-linking is an effective and safe treatment for keratoconus and should be considered a primary treatment to prevent corneal transplant as well as improve vision and corneal irregularity.

[Comparative assessment of functional outcomes of different endothelial keratoplasty techniques]

PURPOSE

Comparative analysis of the higher-order aberrations (HOA) of the cornea after endothelial keratoplasty (EK) using DSAEK and DMEK techniques; evaluation of the correlation between higher-order corneal aberrations and functional outcomes of the treatment.

MATERIAL AND METHODS

The study included 47 patients (59 eyes). The main group consisted of 35 patients (35 eyes) with bullous keratopathy and Fuchs' endothelial dystrophy; among them, 19 patients underwent endothelial keratoplasty using the DSAEK technique and 16 - DMEK technique. The control group included 12 patients (24 eyes) of corresponding age without corneal pathology. Standard and special examination tests were performed before, as well as 6 and 12 months after the operation, including computed tomography and aberrometry of the cornea using the Pentacam HR system. Same tests were performed in the control group.

RESULTS

The values of the main HOA of the anterior corneal surface: RMS coma (Z₃^±1, Z₅^±1), RMS spherical aberration (SA; Z₄⁰, Z₆⁰) and RMS HOA (Z_3-6) 6 months after different EK techniques were statistically significantly higher than in the control group. A statistically significantly lower induction of aberrations of the posterior corneal surface after DMEK technique was revealed. Analysis of the final aberration pattern 6 months after surgery did not reveal any statistically significant differences in the values of the main (RMS coma, RMS SA, RMS HOA) total corneal aberrations after DSAEK and DMEK. A negative correlation was revealed between the best corrected visual acuity (BCVA) and HOA; however, it was statistically significant only for individual aberration values: RMS HOA (Z_3-6) of the posterior corneal aberrations after DMEK (r= -0.634, p=0.049), and RMS coma (Z₃^±1, Z₅^±1) of the cornea after DSAEK (r= -0.57, p=0.042).

CONCLUSION

Comparative analysis of total corneal HOA did not reveal a statistically significant difference in the main parameters: RMS coma, RMS SA, RMS HOA in patients after DSAEK and DMEK surgeries. Correlation analysis did not reveal any statistically significant effects of most aberrations on the functional outcomes of the treatment.

Factors Influencing Contrast Sensitivity Function in Eyes with Mild Cataract

This study was aimed to evaluate the relationship between the area under the log contrast sensitivity function (AULCSF) and several optical factors in eyes suffering mild cataract. We enrolled 71 eyes of 71 patients (mean age, 71.4 ± 10.7 (standard deviation) years) with cataract formation who were under surgical consultation. We determined the area under the log contrast sensitivity function (AULCSF) using a contrast sensitivity unit (VCTS-6500, Vistech). We utilized single and multiple regression analyses to investigate the relevant factors in such eyes. The mean AULSCF was 1.06 ± 0.16 (0.62 to 1.38). Explanatory variables relevant to the AULCSF were, in order of influence, logMAR best spectacle-corrected visual acuity (BSCVA) (p < 0.001, partial regression coefficient B = −0.372), and log(s) (p = 0.023, B = −0.032) (adjusted R² = 0.402). We found no significant association with other variables such as age, gender, uncorrected visual acuity, nuclear sclerosis grade, or ocular HOAs. Eyes with better BSCVA and lower log(s) are more susceptible to show higher AULCSF, even in mild cataract subjects. It is indicated that both visual acuity and intraocular forward scattering play a role in the CS function in such eyes.

Bilateral Ultrathin Descemet's Stripping Automated Endothelial Keratoplasty vs. Bilateral Penetrating Keratoplasty in Fuchs' Dystrophy: Corneal Higher-Order Aberrations, Contrast Sensitivity and Quality of Life

Background and Objectives: The objective of this paper is to compare the visual outcomes and quality of life (QoL) after bilateral ultrathin Descemet's stripping automated endothelial keratoplasty (UT-DSAEK) with bilateral penetrating keratoplasty (PK) for Fuchs' endothelial dystrophy (FED). Materials and Methods: Retrospective comparative cohort study, including 11 patients with FED who underwent bilateral PK and 13 patients with FED who underwent bilateral UT-DSAEK. All patients were already pseudophakic or had undergone a combined cataract procedure. The main outcomes were corrected distance visual acuity (CDVA) corneal higher-order aberrations (HOAs), contrast sensitivity (CS) and quality of life (QoL). Results: The mean follow-up after the second eye surgery was 32.5 ± 10.2 months in PK and 19.6 ± 8.6 months in UT-DSAEK patients. The CDVA in the UT-DSAEK group was significantly better than in the PK one (0.18 ± 0.07 vs. 0.35 ± 0.16 logMAR, p < 0.0001). The mean anterior corneal total HOAs of the central 5 mm were significantly lower in UT-DSAEK eyes than in PK eyes (0.438 ± 0.078 µ and 1.282 ± 0.330 µ respectively, p < 0.0001), whilst the mean posterior total HOAs did not differ between groups (0.196 ± 0.056 µ and 0.231 ± 0.089 µ, respectively, p = 0.253). The CS was lower at 0.75 and 1.5 cycles/degree in P the K group when compared to the DSAEK one (p = 0.008 and 0.005, respectively). The QoL scores by the NEI RQL-42 test exhibited better values in DSAEK patients in 9 out of 13 scales. Conclusion: Our study confirms that UT-DSAEK provides a better visual function in terms of CDVA and CS, together with lower HOAs, when compared to PK. Hence, the vision-related QoL, binocularly evaluated by the NEI RQL-42 items, indicates a higher satisfaction in UT-DSAEK eyes.

Effects of Scleral Contact Lenses for Keratoconus Management on Visual Quality and Intraocular Pressure

Purpose

To evaluate the visual acuity level achieved by scleral contact lens (CL) fitting in patients affected by keratoconus and to evaluate possible intraocular pressure (IOP) changes during the scleral CL wear using a transpalpebral tonometer.

Methods

In a prospective case series a comparison was made between visual acuity obtained with glasses, RGP and 16.8mm diameter scleral CL in 30 consecutive patients affected by keratoconus. IOP was tested during scleral CL wear by transpalpebral Diaton Tonometer (DT) and also by Goldmann Applanation Tonometer (GAT) before and after scleral CL wear.

Results

The mean logMAR visual acuity improved from 0.2±0.25SD with glasses and 0.1±0.02SD with RGP, to −0.002±0.041SD when using the scleral CL (p<0.05). The mean IOP value before scleral CL wear was 12.93mmHg±2.20SD when measured with GAT and 7.85mmHg±2.27SD when measured with DT. During scleral CL wear, IOP was assessed through DT, with a mean value of 8.86mmHg±2.36SD; values were stable after 8 hours of scleral CL use. Immediately after scleral CL removal, the mean IOP measured with GAT was 12.85mmHg ±2.40SD and the mean IOP measured with DT was 7.66mmHg±1.88SD. Therefore, during scleral CL wear, it was evidenced a small but statistically significant increase of the mean IOP value (1.01mmHg; p<0.01), with a reversion to values prior to application when scleral CL was removed.

Conclusion

Scleral CLs remarkably improved visual acuity in keratoconus patients when compared to glasses or RGP contact lenses. Even if it was evidenced a small increase of the mean IOP value during their wear, it may not be significant in otherwise healthy eyes. Statistical analysis demonstrated good agreement between GAT and DT but their numerical values presented a constant gap, that should be taken into account when there is a need to relate the DT values to the reference ones.

Corneal wavefront aberrations and subjective quality of vision after small incision lenticule extraction

PURPOSE

To analyse in depth the associations between objectively measured corneal higher-order aberrations (HOAs) and subjectively perceived visual quality after small incision lenticule extraction (SMILE) as quantified with the standardized and clinically validated quality of vision (QOV) questionnaire.

METHODS

This cross-sectional study included patients after bilateral simultaneous SMILE for the treatment of myopia and/or myopic astigmatism with plano target refraction. Scheimpflug imaging (Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany) was used to objectively quantify corneal HOAs. The standardized and validated QOV questionnaire was employed to gauge patients' subjectively perceived visual quality regarding frequency, severity and bothering effect of visual disturbances.

RESULTS

A total of 394 eyes of 197 patients with a mean age of 32.4 ± 7.7 years and a mean postoperative follow-up of 24.3 ± 14.1 months were included. SMILE induced a statistically significant (p < 0.001) increase in spherical aberration (0.074 ± 0.131 µm), coma (0.142 ± 0.179 µm), trefoil (0.018 ± 0.067 µm) as well as in total HOAs (0.191 ± 0.176 µm). Surgically induced and postoperative levels of HOA showed no correlation with the three QOV scores representative of overall visual symptom frequency, severity and bothering effect (all R² values ≤ 0.016). In addition, the associations between specific visual symptoms (e.g. starburst) and singular HOA terms (e.g. haloes) were very weak (all Rho values ≤ 0.164).

CONCLUSIONS

Small incision lenticule extraction induced significant amounts of corneal HOAs that, however, showed no clear relationships to patient-reported QOV or specific long-term visual symptoms.

The Effect of Lifitegrast on Refractive Accuracy and Symptoms in Dry Eye Patients Undergoing Cataract Surgery

Purpose

To determine the effect of lifitegrast ophthalmic solution 5% on improving the tear film, biometry/keratometry, and refractive accuracy for dry eye patients scheduled for cataract surgery.

Patients and Methods

Multicenter, prospective, open-label study of 100 eyes of 100 patients undergoing cataract surgery who had a confirmed diagnosis of dry eye. Patients underwent biometry at baseline and again after a 28-day course of lifitegrast 5% BID. Primary outcome was an improvement in the accuracy of preoperative anterior corneal power measurements at predicting postoperative spherical equivalent (SE) pre- and post-lifitegrast treatment. Secondary outcomes included changes in dry eye symptoms and corneal staining.

Results

The accuracy of the biometry readings for the achieved refractive SE: within 0.25 D in 47% and 50% of eyes before and after the initial lifitegrast treatment, respectively; within 0.5 D in 71% and 79% of eyes before and after the initial lifitegrast treatment; and within 0.75 D in 81% and 91% of eyes before and after the initial lifitegrast treatment (p < 0.04).

Conclusion

Lifitegrast 5% significantly improved preoperative corneal surface measurement accuracy in patients with confirmed dry eye who were scheduled for cataract surgery.

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Customised aberration-controlling corrections for keratoconic patients using contact lenses

Technological advancements in the design of soft and scleral contact lenses have led to the development of customised, aberration-controlling corrections for patients with keratoconus. As the number of contact lens manufacturers producing wavefront-guided corrections continues to expand, clinical interest in this customisable technology is also increasing among both patients and practitioners. This review outlines key issues surrounding the measurement of ocular aberrations for patients with keratoconus, with a particular focus on the possible factors affecting the repeatability of Hartmann-Shack aberrometry measurements. This review also discusses and compares the relative successes of studies investigating the design and fitting of soft and scleral customised contact lenses for patients with keratoconus. A series of key limitations that should be considered before designing customised contact lens corrections is also described. Despite the challenges of producing and fitting customised lenses, improvements in visual performance and comfortable wearing times, as provided by these lenses, could help to reduce the rate of keratoplasty in keratoconic patients, thereby significantly reducing clinical issues related to corneal graft surgery. Furthermore, enhancements in optical correction, provided by customised lenses, could lead to increased independence, particularly among young adult keratoconic patients, therefore leading to improvements in quality of life.

The influence of orthokeratology compression factor on ocular higher-order aberrations

BACKGROUND

To investigate the influence of compression factor upon changes in ocular higher-order aberrations (HOAs) in young myopic children undergoing orthokeratology treatment.

METHODS

Subjects aged between six and < 11 years, with low myopia (0.50-4.00 D inclusive), low astigmatism (≤ 1.25 D), and anisometropia (≤ 1.00 D), were randomly assigned to wear orthokeratology lenses of different compression factors in each eye (one eye 0.75 D and the fellow eye 1.75 D). HOAs were measured weekly over one month of lens wear. Wavefront analysis was conducted over a 5-mm pupil using a sixth order Zernike polynomial expansion. Linear mixed models were used to examine the individual Zernike co-efficients and specific root-mean-square (RMS) error (spherical, comatic, total HOAs) metrics and their changes between the two eyes during the study period.

RESULTS

Twenty-eight myopic (mean manifest spherical equivalent refraction: -2.10 ± 0.58 D) children (median [range] age: 9.3 [7.8-11.0] years) were analysed. Significant interocular differences in HOAs at baseline were observed for Z 6 - 6 and Z 6 - 4 only (both p < 0.05). During the lens wear period, eyes fitted with the increased compression factor showed greater changes in primary spherical aberration ( Z 4 0 , p = 0.04) and RMS values for spherical and total HOAs (both p < 0.01). Considering data from both eyes together, after adjusting for the paired nature of the data, some other Zernike terms ( Z 3 1 and Z 6 0 , both p < 0.01) and the RMS value of comatic aberrations (p < 0.001) significantly increased after one month of orthokeratology treatment. The increase in primary spherical aberration ( Z 4 0 ) was positively correlated with the reduction in spherical equivalent refractive error, but only in eyes fitted with the increased compression factor (r = 0.69, p < 0.001).

CONCLUSIONS

Increasing the orthokeratology compression factor by 1.00 D significantly altered some HOAs, particularly spherical aberration. Given the association between positive spherical aberration and eye growth in children, further research investigating the influence of orthokeratology compression factor on axial eye growth is warranted.

Evaluation of interface reflectivity and corneal aberrations following Descemet's stripping automated endothelial keratoplasty

PURPOSE:

This study aims to evaluate visual outcome after Descemet's membrane stripping automated endothelial keratoplasty (DSAEK) and relate to interface and corneal higher-order aberrations (HOAs).

MATERIALS AND METHODS:

We enrolled 16 eyes of 16 patients (eight males and eight females) in this interventional case series and followed DSAEK operation for about two to 20 months. OCULUS Pentacam, as well as other ophthalmic evaluations in follow-up visits, examined interface reflectivity and HOAs. Statistical relations were analyzed.

RESULTS:

There was statistically significant correlation between interface reflectivity and best corrected visual acuity (BCVA) (r = 0.56, P = 0.021). Pachymetry (central corneal thickness) and BCVA had a moderate correlation (r = 0.6, P = 0.013). There was no statistically significant correlation between pachymetry and follow-up time (r = −0.36, P = 0.16). Negative correlation between follow-up and interface reflectivity was also not statistically significant (r = −0.24, P = 0.35). Coma had a significant correlation with BCVA in cornea and cornea front maps (r = 0.74, P = 0.009 and r = 0.71, P = 0.013, respectively).

CONCLUSION:

Significant correlation between interface reflectivity and BSCVA was found, and anterior corneal HOAs are significantly higher than posterior HOAs.

Corneal backward scattering and higher-order aberrations in children with vernal keratoconjunctivitis and normal topography

PURPOSE

To investigate the corneal backward scattering and higher-order aberrations (HOAs) in children with vernal keratoconjunctivitis (VKC) and normal topography.

METHODS

Thirty-six eyes of 22 patients with VKC and 54 eyes of 34 normal subjects were included. All participants had clear cornea, absence of dry eyes and a normal corneal tomography. Scheimpflug imaging was used to measure corneal backward scattering in zones centred on the corneal apex (central 2-mm zone and paracentral 2- to 6-mm zone), and HOAs were compared between VKC and normal control.

RESULTS

The mean age of participants was 12.0 ± 4.1 years in VKC group and 11.2 ± 4.1 years in control group (p = 0.339). There was no significant intergroup difference in mean keratometry, astigmatism and apex pachymetry (p ≥ 0.076). Total corneal backscatter was higher in the VKC group compared to the control group (p ≤ 0.012). Anterior and posterior cornea displayed a higher level of backward scattering in the VKC group (p < 0.001 for anterior; p ≤ 0.048 for posterior). Patients with VKC exhibited higher total HOAs and coma (p ≤ 0.036). There were significant correlations between total anterior HOAs and backward scattering measured at the central (r = 0.500; p = 0.032) and paracentral zones (r = 0.470; p = 0.024) for VKC.

CONCLUSION

The current study showed optical quality changes in patients with clear corneas and quiescent VKC. An increase in corneal backward scattering and HOAs was noted in patients with VKC as compared to normal patients.

Impact of Forward and Backward Scattering and Corneal Higher-Order Aberrations on Visual Acuity after Penetrating Keratoplasty

PURPOSE

To assess the relationship of forward and backward scattering and corneal higher-order aberrations (HOAs) with corrected distance visual acuity (CDVA) after penetrating keratoplasty (PK).

METHODS

This retrospective study comprised 25 eyes of 25 consecutive patients who underwent PK using the VisuMax femtosecond laser system and age-matched 25 eyes of 25 healthy subjects. We quantitatively assessed objective scattering index (OSI) using the double-pass instrument (OQAS II, Visiometrics), corneal densitometry (CD) and corneal HOAs with the Scheimpflug rotating camera (Pentacam HR, Oculus) 1 year postoperatively.

RESULTS

The OSI, CD, and corneal HOAs were significantly larger in the PK group than those in the control group (p ≤ 0.011). We found significant correlations of logMAR CDVA with the OSI (r = 0.477, p = 0.016), and with the anterior, posterior, and total corneal HOAs of the central 4-mm zone (anterior: r = 0.573, p = 0.003, posterior: r = 0.596, p = 0.002, total: r = 0.472, p = 0.017), but no significant association with the CD of the 0-2 mm zone at any layers (anterior: r = 0.236, p = 0.257, center: r = 0.139, p = 0.506, posterior: r = 0.073, p = 0.728, total: r = 0.212, p = 0.308). Similar results were obtained when the analysis was repeated with corneal HOAs of the central 6-mm zone and CDs in 2-6 mm zone.

CONCLUSIONS

Our pilot study demonstrated that the postoperative CDVA was significantly correlated with OSI and corneal HOAs, but not with backward scattering in post-PK eyes, suggesting that OSI as well as corneal HOAs plays an essential role in postoperative visual performance after PK.

Effects of higher-order aberrations on contrast sensitivity in normal eyes of a large myopic population

AIM

To study the relation between higher-order aberrations (HOAs) and contrast sensitivity (CS) in normal eyes among a population of laser in situ keratomileusis (LASIK) candidates.

METHODS

In 6629 eyes of 3315 LASIK candidates, CS were measured under dark environment at the spatial frequencies of 1.5, 3, 6, 12 and 18 cycles per degree (c/d), respectively, using an Optec 6500 visual function tester. Meanwhile, ocular HOAs were measured for a 6.0 mm pupil with a Hartmann-Shack wavefront analyzer.

RESULTS

In the study, the subjects with an average spherical equivalent of -4.86±2.07 D were included. HOAs decreased from the third to the sixth order aberrations with predominant aberrations of third-order coma, trefoil and fourth-order spherical aberration. At low and moderate spatial frequencies, CS was negatively correlated with the third-order coma and trefoil aberrations, and decreased with increasing Z₃¹, but increased with increasing Z₃^-3 and Z₅^-1. At high spatial frequencies, CS decreased with increasing Z₃^-3 and increased with increasing Z₅^-1.

CONCLUSION

At a large pupil size of 6.0 mm, the third-order aberrations, but not the total aberrations, are the main factors affecting CS. Vertical coma is negatively correlated with CS.

Peripheral aberrations in adult hyperopes, emmetropes and myopes

PURPOSE

To determine differences in peripheral aberrations in hyperopic, emmetropic and myopic groups.

METHODS

Cycloplegic peripheral aberrations for 5 mm pupils were measured at 39 locations across 42° × 32° of right eye visual fields with a COAS-HD Hartmann-Shack aberrometer in nine hyperopes (mean age 29 ± 5 years, spherical equivalent refraction M + 1.47 ± 0.58 D), 20 emmetropes (28 ± 7 years, +0.06 ± 0.36 D) and 20 myopes (27 ± 6 years, -2.55 ± 1.82 D). Relative peripheral refraction error RPRE and 3rd-4th order Zernike coefficients were compared between the groups.

RESULTS

Hyperopes and emmetropes had relative peripheral myopia across the visual field, with considerable nasal-temporal asymmetry for both groups and superior-inferior asymmetry for hyperopes. Myopes had minimal RPRE along the horizontal meridian, but myopic RPRE along the vertical meridian which was less than the other groups. There was little difference between groups in astigmatic components or higher-order Zernike coefficients, except for fourth-order spherical aberration which was more positive in hyperopes than in both emmetropes (mean difference ±95% CI = +0.05 ± 0.05 μm, p = 0.03) and myopes (+0.07 ± 0.04 μm, p = 0.003). Coma changed rapidly across the visual field with similar rates for all groups.

CONCLUSIONS

Hyperopes and emmetropes had greater relative peripheral myopia than myopes. There was asymmetry in RPRE along the vertical meridian for hyperopes which was not present in the emmetropes, suggesting there may be asymmetries in peripheral eye length along the vertical meridian for the former. Higher-order aberrations were affected by field eccentricity, but refractive error affected only the spherical aberration coefficient, which was more positive for hyperopes than for other groups.

Changes in meibomian gland morphology and ocular higher-order aberrations in eyes with chalazion

PURPOSE

To examine the changes in meibomian gland morphology and ocular higher-order aberrations (HOAs) in eyes with chalazion and its excision.

METHODS

Seven male patients with previous history of chalazion excision and seven control male subjects were enrolled. Changes in meibomian gland morphology (meiboscores, gland dropout, and shortening) were evaluated by using meibography equipped in a wavefront analyzer KR-1W and in a slit-lamp device BG-4M. Ocular HOAs were measured sequentially with KR-1W. The tear film breakup time (BUT) was measured.

RESULTS

Both KR-1W and BG-4M visualized meibomian gland as clear similar images. The tear film BUT (mean ± SD, 5.6±3.0 vs 9.4±2.3 seconds, P=0.025), the total meiboscore (median [interquartile range], 2 (2-3) vs 0 (0-1), P=0.007) as well as the meibomian gland dropout rate (86% vs 14%, P=0.008) and shortening rate (100% vs 29%, P=0.031) differed significantly between the patient and control groups. The first total ocular HOAs (0.142±0.063 vs 0.130±0.015, P=0.80) were similar in both groups, whereas the stability index of the total HOAs over time (0.0041±0.0048 vs -0.0012±0.0020, P=0.030) differed significantly between the patient and control groups.

CONCLUSIONS

Chalazion and its excision were associated with dropout and shortening rate of meibomian glands. The morphological changes of meibomian glands in chalazion may be associated to instability of the tear film, which was suggested by the tear film BUT and the stability of ocular HOAs.

Effects of 3% diquafosol sodium ophthalmic solution on higher-order aberrations in patients diagnosed with dry eye after cataract surgery

Purpose

To evaluate the effects of diquafosol sodium ophthalmic solution 3% (DQS) and artificial tears (AT) on higher-order aberrations (HOAs) in patients with dry eye after cataract surgery.

Design

This was a post hoc analysis of a previously conducted randomized clinical study.

Methods

Fifty-nine eyes from 42 patients (17 males and 25 females, aged 72.6±8.0 years) with verified or suspected dry eye at 4 weeks after cataract surgery were evaluated. The dry eye patients were randomly assigned to receive DQS or AT for 4 weeks. Tear breakup time (BUT), corneal and conjunctival fluorescein staining scores, and HOAs were analyzed before and after instillation. HOAs were measured consecutively for 10 seconds with a wavefront analyzer. Average HOAs, HOA fluctuations (fluctuation index [FI]) and changes in HOAs (stability index [SI]) were compared within and between the two groups.

Results

After 4 weeks of instillation, BUT significantly increased (P=0.001) compared with preinstillation values in the DQS group, but not in the AT group. This increase in BUT in the DQS group was significantly greater than in the AT group (P=0.014). Corneal and conjunctival fluorescein staining scores after instillation significantly improved compared with preinstillation values in the DQS group (P=0.018). In HOAs, the cornea aberration changed from an upward curve (a sawtooth pattern) to an almost constant value (a stable pattern) in the DQS group, but not in the AT group. In FI and SI, there were no significant changes in either group; however, FI and SI were significantly lower in the DQS group than in the AT group (both, P=0.004).

Conclusion

The dry eye patients after cataract surgery had a visual dysfunction in HOAs. DQS is effective to treat dry eye disease after cataract surgery with improvement of visual function.

Association between multifocal soft contact lens decentration and visual performance

PURPOSE

The aim of this study was to assess the association between decentration of several commercial multifocal soft contact lenses (MFCLs) and various objective and subjective visual performance variables in presbyopic and non-presbyopic participants.

MATERIALS AND METHODS

All presbyopic (age >40 years, near add ≥+1.25 D) and non-presbyopic (age ≥18 years, no near add requirements, spherical equivalent ≤-0.50 D) participants were each fitted bilaterally with six and two MFCLs (test lens), respectively, and with one single vision lens (control lens). Lens decentration, ie, the x- and y-differences between the contact lens and pupil centers, was objectively determined. Third-order aberrations were measured and compared. Visual performance (high- and low-contrast acuities and several subjective variables) was analyzed for any associations (Pearson's correlation, r) with MFCL decentration.

RESULTS

A total of 17 presbyopic (55.1±6.9 years) and eight non-presbyopic (31.0±3.3 years) participants completed the study. All lenses displayed a temporal-inferior decentration (x=-0.36±0.29 mm, y=-0.28±0.28 mm, mean ± SD). Compared to the control, a significant inferior decentration was found for the Proclear® MFCL Near lens in both groups (ypresbyopic =-0.26 mm, ynon-presbyopic =-0.70 mm) and for the Proclear® MFCL Distance lens in the non-presbyopic group (ynon-presbyopic =-0.69 mm). In both groups, lens-induced vertical coma (C(3, -1)) was, by at least tenfold, significantly more positive for the Proclear® MFCL Distance lens and significantly more negative for the Proclear® MFCL Near lens. In the presbyopic group, the correlation of total MFCL decentration with vision variables was weak (r<|0.191|). Conversely, a moderate but significant correlation with total MFCL decentration was found in the non-presbyopic group for most of the vision variables, indicating a decrease in vision as decentration increased.

CONCLUSION

Certain MFCLs decentered more than others; the same lens designs also induced significant amounts of third-order aberrations. An association between MFCL decentration and seven out of nine vision variables was found in the non-presbyopic group, ie, the group where lenses were most decentered, which had larger pupils and lower levels of inherent third-order aberrations.

Comparison of the femtosecond laser and mechanical microkeratome for flap cutting in LASIK

AIM

To compare refractive results, higher-order aberrations (HOAs), contrast sensitivity and dry eye after laser in situ keratomileusis (LASIK) performed with a femtosecond laser versus a mechanical microkeratome for myopia and astigmatism.

METHODS

In this prospective, non-randomized study, 120 eyes with myopia received a LASIK surgery with the VisuMax femtosecond laser for flap cutting, and 120 eyes received a conventional LASIK surgery with a mechanical microkeratome. Flap thickness, visual acuity, manifest refraction, contrast sensitivity function (CSF) curves, HOAs and dry-eye were measured at 1wk; 1, 3, 6mo after surgery.

RESULTS

At 6mo postoperatively, the mean central flap thickness in femtosecond laser procedure was 113.05±5.89 µm (attempted thickness 110 µm), and 148.36±21.24 µm (attempted thickness 140 µm) in mechanical microkeratome procedure. An uncorrected distance visual acuity (UDVA) of 4.9 or better was obtained in more than 98% of eyes treated by both methods, a gain in logMAR lines of corrected distance visual acuity (CDVA) occurred in more than 70% of eyes treated by both methods, and no eye lost ≥1 lines of CDVA in both groups. The difference of the mean UDVA and CDVA between two groups at any time post-surgery were not statistically significant (P>0.05). The postoperative changes of spherical equivalent occurred markedly during the first month in both groups. The total root mean square values of HOAs and spherical aberrations in the femtosecond treated eyes were markedly less than those in the microkeratome treated eyes during 6mo visit after surgery (P<0.01). The CSF values of the femtosecond treated eyes were also higher than those of the microkeratome treated eyes at all space frequency (P<0.01). The mean ocular surface disease index scores in both groups were increased at 1wk, and recovered to preoperative level at 1mo after surgery. The mean tear breakup time (TBUT) of the femtosecond treated eyes were markedly longer than those of the microkeratome treated eyes at postoperative 1, 3mo (P<0.01).

CONCLUSION

Both the femtosecond laser and the mechanical microkeratome for LASIK flap cutting are safe and effective to correct myopia, with no statistically significant difference in the UDVA, CDVA during 6mo follow-up. Refractive results remained stable after 1mo post-operation for both groups. The femtosecond laser may have advantages over the microkeratome in the flap thickness predictability, fewer induced HOAs, better CSF, and longer TBUT.

Effect of diquafosol ophthalmic solution on the optical quality of the eyes in patients with aqueous-deficient dry eye

PURPOSE

To investigate the short- and long-term effects of diquafosol ophthalmic solution on the optical quality of the eyes in patients with aqueous-deficient dry eye.

METHODS

Sixteen eyes in 16 patients with mild or moderate aqueous-deficient dry eye were treated with 3% diquafosol ophthalmic solution. Ocular higher-order aberrations (HOAs) were measured with a wavefront sensor before and at 15 min after diquafosol instillation at the baseline visit and at 4 weeks after treatment initiation. Dry eye symptoms, tear break-up time (BUT), corneal/conjunctival fluorescein staining and Schirmer's test were also evaluated before and after treatment with diquafosol.

RESULTS

Treatment with diquafosol ophthalmic solution significantly improved dry eye symptoms, corneal staining and BUT. Compared with mean total HOAs at baseline (0.180 ± 0.06 μm), those at 4 weeks after treatment significantly decreased (0.148 ± 0.039 μm; p = 0.035), whereas those 15 min after diquafosol instillation at the baseline visit did not change significantly (0.170 ± 0.049 μm; p = 0.279).

CONCLUSIONS

Although no significant change in HOAs was observed as a short-term effect of a single-drop instillation of diquafosol, long-term use of diquafosol to treat aqueous-deficient dry eye reduced HOAs as well as improved corneal epithelial damage and tear film stability.

Comparisons of amplitude of pseudoaccommodation with aspheric yellow, spheric yellow, and spheric clear monofocal intraocular lenses

Purpose

To determine the amplitude of pseudoaccommodation and higher-order aberrations with three types of implanted monofocal intraocular lenses (IOLs): aspheric yellow (IQ); spheric yellow (NT); and spheric clear (AT).

Setting

Department of Ophthalmology, Nara Medical University, Nara, Japan.

Methods

We studied 60 patients who underwent small incision phacoemulsification with the implantation of a monofocal IQ, NT, or AT IOL. The pseudoaccommodation was measured by the lens-loading method, and the postoperative ocular higher-order aberrations were measured with a Hartmann–Shack wavefront analyzer through natural and 4 mm pupils.

Results

Sixty eyes of 60 patients were studied. The average amplitude of the pseudoaccommodation was 0.45±0.24 D with the IQ IOL, which was significantly lower than that with the AT IOL at 0.81±0.37 D (Tukey’s test; P<0.01). The differences in the amplitude of the pseudoaccommodation between the IQ and the NT IOLs, and between the NT and the AT IOLs were not significant (Tukey’s test; P>0.05). The degree of spherical aberration was significantly different for the IQ, NT, and AT lenses (analysis of variance, P=0.016). The spherical aberration through the IQ IOL was significantly lower than that through the NT and the AT IOLs (Tukey’s test; P<0.01). The fourth-order RMS (root mean square) aberration of the IQ lens was also significantly lower than that of the NT and AT IOLs (Tukey’s test; P<0.01).

Conclusion

Our results suggest that the spherical aberration and selective spectral transmission of IOLs may work together to increase the amplitude of the pseudoaccommodation.

Short-term effects of overnight orthokeratology on corneal epithelial permeability and biomechanical properties

PURPOSE

To investigate the effects of 30 nights of overnight orthokeratology (OOK) on corneal epithelial permeability (Pdc) and corneal biomechanical properties.

METHODS

BE Retainer and Paragon CRT lenses were used. Visits were scheduled approximately 4 hours after awakening at baseline and after 1, 5, 10, 14, and 30 days of treatment. Pdc was measured at baseline and at day 30, whereas corneal biomechanical properties and visual acuities (VAs) were measured at all visits.

RESULTS

Thirty-nine neophytes and soft contact lens wearers completed the study. There was no difference in Pdc between baseline (ln[Pdc] [95% confidence interval (CI)] = -2.65 [-2.80 to -2.50]) and day 30 (ln[Pdc][CI] = -2.68 [-2.85 to -2.50]) (P = 0.88). Corneal hysteresis (CH) and corneal resistance factor (CRF) reduced significantly from baseline (CH [CI] = 10.89 [10.59-11.19] mm Hg and CRF [CI] = 10.35 [9.99-10.72] mm Hg) to day 30 (CH [CI] = 10.59 [10.31-10.87] mm Hg and CRF [CI] = 9.58 [9.26-9.89] mm Hg) (P = 0.001 for CH and P < 0.001 for CRF). Posttreatment VA did not reach baseline targets, and the difference was worse with low-contrast letters. Asian individuals (n = 18) had significantly worse VA than non-Asian individuals (n = 21) under most conditions through day 5, and the difference extended through day 14 with low-contrast letters under mesopic conditions. The percentage of participants who achieved 20/20 uncorrected was 17% Asian and 40% non-Asian individuals after day 1 and reached 69% Asian and 83% non-Asian individuals at day 30.

CONCLUSIONS

Thirty nights of OOK did not alter Pdc when measured 4 hours after awakening. OOK caused CH and CRF to decrease, but the changes were not clinically significant compared with diseased and postsurgical cases. Asian individuals, who had lower baseline CH in this study, responded slower to OOK based on early uncorrected VA and overrefraction measurements.

Evolution of visual performance in 70 eyes implanted with the Tecnis(®) ZMB00 multifocal intraocular lens

PURPOSE

To evaluate the development of visual acuity, dysphotopsia phenomena, and subjective sensations in patients implanted with the Tecnis(®) ZMB00 (Advanced Medical Optics Inc, Santa Ana, CA) multifocal intraocular lens.

METHODS

In a sample of 70 eyes, distance and near visual acuity, with and without correction, contrast sensitivity, and patient satisfaction, were analyzed at 15, 30, and 60 days post-surgery.

RESULTS

Mean uncorrected distance visual acuity (logarithm of minimum angle of resolution) at 15, 30, and 60 days was 0.194 ± 0.054, 0.119 ± 0.026, and 0.076 ± 0.014 (P < 0.0001), respectively, and with correction, 0.051 ± 0.007 vs 0.041 ± 0.004 vs 0.022 ± 0.002 (P < 0.0001), respectively. At 60 days, 94.3% of eyes could read 1.00 close-up without correction. Patient satisfaction in terms of dysphotopsia effects and visual acuity was excellent. The mean contrast sensitivity was 1.64 ± 0.10 (logarithmic units) measured with the Pelli-Robson test.

CONCLUSION

This type of multifocal intraocular lens was very effective at the distances analyzed, producing excellent objective and subjective results.

Transient increase of higher-order aberrations after lateral rectus recession in children

The changes of higher-order aberrations (HOAs) after bilateral lateral rectus muscle recession were evaluated. Forty eyes of 20 children were enrolled and their wavefront information was assessed until postoperative 3 months. Even though the root mean square (RMS) of total aberration was not changed, the RMS of HOA was transiently increased at postoperative 1 week and returned to baseline level after 1 month. Among individual Zernike coefficient, secondary astigmatism, quadrafoil, secondary coma, secondary trefoil, and pentafoil showed similar tendency with the RMS of HOA. However, coma, trefoil, and spherical aberration were not changed. Regarding recession amount, it did not correlate with any Zernike coefficient. In summary, our data imply that the HOAs are transiently increased after lateral rectus recession surgery. These results are in collusion with previous reports that strabismus surgery induced transient corneal astigmatism.

Corneal Aberrations Before and After Photorefractive Keratectomy

Purpose

To determine whether - and which - higher-order corneal aberrations, up to the sixth order, are induced by photorefractive keratectomy (PRK).

Methods

197 eyes of 197 patients have been examined with a corneal aberrometer for a 3.5 and a 6.0 mm pupil simulation, both before and 1, 3, 6 months after myopic PRK treatment ranging from −15.25 D to -0.5 D (mean −5.31±2.95 D). The statistical evaluation was performed using a paired Student's T-test.

Results

After PRK there is a clear-cut increase in almost all the higher-order corneal aberrations for both a 3.5 and a 6.0 mm pupil simulation. These aberrations tend to normalize after 3 and 6 months mainly for a 3.5 mm simulation, whereas such normalization is not present for a 6.0 mm simulation.

Conclusions

PRK induces significant aberrations both for 3.5 and 6 mm pupils, 1 month after PRK, but a trend towards normalization is evident at the 6 month follow-up for the smaller pupil size.