Quality of vision and patient satisfaction after LASIK

BCLA CLEAR Presbyopia: Management with corneal techniques

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report reviews the evidence for the treatment profile, safety, and efficacy of the current range of corneal techniques for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. In presbyopia correction by conductive keratoplasty, radiofrequency energy is applied to the mid-peripheral corneal stroma, leading to mid-peripheral corneal shrinkage and central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Agreement and repeatability of scotopic pupil size measurement with the 2WIN-S portable refractor in Chinese adults

To assess the agreement and repeatability of scotopic pupil size measurement using 2WIN-S (Adaptica, Padova, Italy) portable refractor in Chinese adults. This prospective non-randomized open-label controlled study assessed the scotopic pupil size of 100 right eyes using OPD-Scan III (Optical path difference) (Nidek Technologies, Gamagori, Japan) and 2WIN-S. OPD-Scan III and 2WIN-S measure pupil size using infrared light and detector, while 2WIN-S measures bilateral eyes simultaneously, OPD-Scan III measures unilateral eyes individually. Participants were first measured once using OPD-Scan III and two consecutive measurements were performed using 2WIN-S after 15 min of rest interval. The primary outcome was to evaluate the agreement between 2WIN-S and OPD-Scan III, and the secondary outcome was to evaluate the repeatability of 2WIN-S. Scotopic pupil size of 100 right eyes of 100 adults (28 male and 72 female) aged 18-53 years (mean 36 ± 12 years) was assessed using OPD-Scan III and 2WIN-S, respectively. The mean scotopic pupil size of OPD-Scan III and 2WIN-S was recorded to be 6.24 ± 0.88 mm and 6.27 ± 0.81 mm, respectively. For the mean scotopic pupil size of OPD-Scan III and 2WIN-S the difference was - 0.03 mm (95%CI - 0.10 to 0.04 mm), p = 0.445, the 95% limits of agreement (LOA) was - 0.71 to 0.66 mm. ICC between the two devices was 0.92 (95% CI 0.88-0.94) (ICC > 0.9 indicates excellent consistency). Coefficients of repeatability (CoR) of 2WIN-S was 0.37, which has a high repeatability. For the mean scotopic pupil size of 2WIN-S of the repeated measurements, the difference was -0.04 mm (95%CI - 0.08 to 0.01 mm), p = 0.019, the 95% limits of agreement (LOA) was - 0.41 to 0.32 mm, with a narrow LOA. However, the majority of the variations were less than ± 0.50 mm (98% of scotopic pupil size measurements were below this threshold), within the clinically acceptable range (± 0.50 mm). Our study showed excellent agreement between 2WIN-S and OPD-Scan III (ICC > 0.9) and a good repeatability of 2WIN-S (CoR = 0.37). This study suggests a novel technique for measuring pupillary responses in low light conditions, which can be considered an alternative to OPD-Scan III in clinical settings.

Patient-Reported Outcomes and Higher Order Aberrations Following Topography-Guided Femtosecond Laser-Assisted In Situ Keratomileusis

PURPOSE

To examine patient-reported outcomes and higher order aberrations following topography-guided laser-assisted in situ keratomileusis (LASIK).

METHODS

This was a prospective, nonrandomized observational study at a single academic center. Sixty eyes from 30 patients underwent bilateral topography-guided femtosecond LASIK for correction of myopia using the VisuMax 500 femtosecond laser (Zeiss; Oberkochen, Germany) and Allegretto Wave Eye-Q 400 Hz Excimer Laser (Alcon/Wavelight; Erlangen, Germany) with the Contoura topography system (Alcon; Geneva, Switzerland) for topography-modified refraction. The main outcomes of this study were higher order aberrations (HOAs) and results from the Patient-Reported Outcomes with LASIK questionnaire.

RESULTS

There was a small, significant increase in HOA root mean square, spherical aberration, and coma at 1, 3, 6, and 12 months following topography-guided LASIK (all P < 0.05), but no change in trefoil. In addition, self-reported worry related to vision (P < 0.001) and ability to perform activities (P < 0.001) significantly improved after surgery. The prevalence of double images, glare, halos, or starbursts decreased from 73% preoperatively to 56%, and no participants reported "very" or "extremely" bothersome visual symptoms after 12 months. Dry eye symptoms per Ocular Surface Disease Index score decreased significantly at 6 (P = 0.01) and 12 (P = 0.002) months after surgery. There was a 100% satisfaction rate with visual outcomes and duration of time to improvement in vision following the procedure.

CONCLUSIONS

Although there was an increase in HOAs following topography-guided LASIK, there were significant improvements in the presence of double images, glare, halos, and starbursts and vision-related quality-of-life metrics. Overall satisfaction rates in this study were high.

Clinical outcomes and higher order aberrations of wavefront-guided LASIK versus SMILE for correction of myopia: A systemic review and meta-analysis

To systematically evaluate the clinical effect of wavefront-guided laser in situ keratomileusis (WFG-LASIK) and small incision lenticule extraction (SMILE) in terms of refractive errors and high-order aberrations. A systematic literature search of PubMed, EMBASE, the Cochrane Library, Web of Science and China National Knowledge Internet was performed to identify studies evaluating the clinical outcomes of SMILE and WFG-LASIK ended in May 2022. Meta-analyses were performed according to the PRISMA guidelines. The risk of bias of the RCTs was evaluated using the Cochrane Handbook criteria, and the quality of the non-randomised controlled studies was assessed using the Newcastle-Ottawa Scale. In total, 1385 eyes (SMILE group, 750 eyes; WFG-LASIK group, 635 eyes) from 12 studies were included. The meta-analysis demonstrated that spherical aberration was smaller in the SMILE group than in the WFG-LASIK group (standardised mean difference [SMD]: -0.34, 95% confidence interval [CI]: -0.47, -0.22; p < 0.00001), and that the postoperative values of vertical coma (SMD: 0.83; 95% CI: 0.63, 1.03; p < 0.00001) and trefoil (SMD: 0.37; 95% CI: 0.02, 0.72; p = 0.04) were higher in the SMILE group compared to the WFG LASIK group. There were no significant differences in the clinical outcomes and the values of induced total higher order aberrations between the WFG-LASIK and SMILE groups (SMD: 0.05; 95% CI: -0.09, 0.19; p = 0.47). Both SMILE and WFG-LASIK were found to be safe, effective, and predictable. SMILE may induce more vertical coma and trefoil, whereas WFG LASIK may induce more spherical aberrations, but no significant differences were found in the total higher order aberrations between SMILE and WFG-LASIK.

Reversal of Myopic Correction for Patients Intolerant to LASIK

Purpose

To evaluate the outcome of the reversal of myopia correction in patients intolerant to LASIK.

Methods

This study is a retrospective and case series of patients who decided to reverse their previous myopic LASIK correction between July 2012 and July 2020. It was conducted at a private refractive surgery centre, Ismailia, Egypt. The patients were followed up after reversal treatment for one year. Primary LASIK and reversal treatment were performed by a 500 kHz Amaris excimer laser platform. The main outcomes included refractive predictability, stability, efficacy, and safety and any reported complications.

Results

This study included 48 eyes of 24 patients (6 male and 18 female patients). The average duration between the primary LASIK surgery and reversal treatment was 3.20 ± 0.30 months (range 3 to 4 months). Reversal treatment was bilateral in all patients. The mean age of the patients was 38 ± 1.9 years (range 37 to 45 yrs). After reversal, the mean postreversal cycloplegic refraction spherical equivalent was −1.82 ± 0.34 D (range −1.50 to −3.00 D). The mean ablation depth was 34.10 ± 7.36 μm (range 20 to 46 μm), and the mean of the central corneal thickness 12 months after reversal treatment was 510.2 ± 14.4 μm (range 515 to 487 μm). The mean keratometric reading was 42.6 ± 1.6 (range 42.5 to 44.8). The mean of CDVA was 0.2 ± 0.03 log MAR (range −0.10 to 0.4 log MAR). The mean optical zone of reversal treatment was 6.1 ± 0.3 mm (range 5.9 to 6.2 mm). UDVA was 0.4 log MAR in 87.5% of the patients, 0.5 log MAR in 8.3% of the patients, and 0.6 log MAR in 4.2% of the patients. CDVA remained unchanged in 83.3% of patients; 2.1% of the patients gained one line of CDVA (Snellen); 8.3% of the patients lost one line of CDVA; 6.3% of the patients lost two lines of CDVA. No cases of corneal ectasia were recorded. The only postoperative complications were flap microfolds in 3 eyes (6.25%).

Conclusion

In conclusion, this study demonstrates that reversal of myopic LASIK treatment is a safe, stable, and effective option for intolerant patients.

Topography-Guided Versus Wavefront-Optimized LASIK for Myopia With and Without Astigmatism: A Meta-analysis

PURPOSE

To evaluate the differences in efficacy, predictability, safety, and visual quality between topography-guided customized ablation treatment (TCAT) and wavefront-optimized (WFO) laser in situ keratomileusis (LASIK) for the treatment of myopia with and without astigmatism.

METHODS

A comprehensive literature search of PubMed, Embase, the Cochrane library, Web of Science, and ClinicalTrials was used to identify randomized controlled trials (RCTs) comparing TCAT-LASIK with WFO-LASIK for myopia with and without astigmatism up to September 2020. The references of all searched literature were checked as supplements. Literature was screened according to the inclusion and exclusion criteria and relative data were extracted. RevMan software version 5.3.0 (Cochrane Collaboration) was used for meta-analysis.

RESULTS

A total of seven RCTs (1,168 eyes) were included. There were no statistically significant differences in the ratio of uncorrected distance visual acuity of 20/20 or better (relative risk [RR] = 1.01, 95% CI [0.97 to 1.06], P = .64) and 20/16 or better (RR = 0.96, 95% CI [0.80 to 1.16], P = .69). Compared with WFO-LASIK, TCAT-LASIK achieved a higher proportion of postoperative manifest refractive spherical equivalent within ±0.50 diopters of the target (RR = 1.06, 95% CI [1.02 to 1.11], P = .003) and less surgically induced higher order aberrations (weighted mean difference [WMD] = -0.11, 95% CI [-0.15 to -0.0], P < .00001), spherical aberrations (WMD = -0.04, 95% CI [-0.05 to -0.03], P < .00001), and coma (WMD = -0.15, 95% CI [-0.28 to -0.01], P = .03). No patient lost two or more lines of distance-corrected visual acuity postoperatively in the two groups.

CONCLUSIONS

This meta-analysis suggests that both TCATLASIK and WFO-LASIK show excellent efficacy, predictability, and safety for myopia. TCAT-LASIK exhibited more accurate postoperative refraction predictability and less surgically induced higher order aberrations, spherical aberrations, and coma. More randomized, prospective, and large sample-sized studies are needed to confirm these conclusions in the long term. [J Refract Surg. 2021;37(10):707-714.].

Safety and Efficacy of Myopic LASIK performed on Thin Corneas

Purpose:

The aim was to report on the visual outcomes and safety of myopic LASIK performed in patients with corneas of central thickness below average(<540μm) and normal topography.

Methods:

This is a retrospective cohort study conducted at a private practice setting on Mexican Hispanic patients who underwent myopic LASIK between January 2014 and January 2015. An analysis of records of patients >18 years-old with previous normal topography, stable refraction, corrected visual acuity ≥ 20/20 (Snellen), Central Corneal Thickness (CCT) < 540μm and at least 12 months follow up after surgery was conducted. The main outcome measures were standard visual outcomes (efficacy, safety, refractive stability) and Percent Tissue Altered (PTA) analysis was conducted.

Results:

A total of 51 patients (102 eyes) were included; 56% (n=57) were female. The mean age was 26.52 ± 8.06 (range 18-55 years) with a mean follow up of 13.9 ± 1.2 months. Preoperative CCT was 515.44 ± 17.87μm (range 452- 540μm), with a mean refractive spherical equivalent (SEQ): -4.08 ± 2.17 D (range -0.75 to -9.75 D), and mean refractive cylinder: -1.44 ± 1.29 D (range 0.00 to -6.00 D). Mean predictability of postoperative SEQ was -0.20 ± 0.40 D (range -1.25 to +1.25). Postoperative SEQ was ±0.50 D in 71%, ±1.00 D in 93% of the eyes. Postoperative uncorrected distance visual acuity was ≥20/20 in 78% and ≥20/25 in 95%. One line of CDVA was lost in 3% of the eyes, no eyes lost ≥2 lines. No ectasia cases were observed during follow-up.

Conclusion:

LASIK surgery in Mexican Hispanic patients with thinner than “normal” corneas (<540 μm) is safe, efficient and predictable at 1 year follow up for myopic refractive corrections with no evidence of postoperative keratectasia.

Pyramidal Aberrometry in Wavefront-Guided Myopic LASIK

PURPOSE

To evaluate measurement repeatability and clinical results for pyramidal aberrometry in routine myopic wavefront-guided laser in situ keratomileusis (LASIK).

METHODS

Results from 265 consecutive eyes treated with myopic wavefront-guided LASIK using the Amaris 1050RS Excimer Laser and Peramis pyramidal aberrometer (SCHWIND eye-tech-solutions GmbH) were reviewed. Limits of repeatability were calculated for the aberrometric refraction spherical equivalent and higher order aberrations for the Peramis aberrometer using results from three consecutive scans acquired preoperatively and postoperatively for the first 100 eyes treated.

RESULTS

The 95% limits of repeatability for pyramidal aberrometric measurement were: 0.3 diopters (D) for sphere, 0.2 D for cylinder, and 0.1 D (dioptric equivalent) for 3rd and 4th order aberration indices. A total of 95% of eyes were within ±0.50 D of the manifest refraction spherical equivalent target postoperatively. Uncorrected distance visual acuity was 20/20 or better in 96% of 232 eyes with a plano refraction target outcome. A total of 97% of eyes had a refraction cylinder of 0.50 D or less. No eyes lost one or more line of corrected distance visual acuity.

CONCLUSIONS

These data demonstrate good measurement repeatability, safety, and efficacy for pyramidal aberrometry in routine myopic LASIK. [J Refract Surg. 2020;36(7):442-448.].

Reasons for Laser in Situ Keratomileusis in China: A Qualitative Study

SIGNIFICANCE

Myopia is a major health issue in East Asian countries, especially in China. By identifying Chinese patients' motivations for laser in situ keratomileusis (LASIK) surgery, our results are expected to help clinicians counsel patients before LASIK surgery and to maximize patients' post-operative LASIK surgery satisfaction, improving the quality of LASIK surgery services.

PURPOSE

Laser in situ keratomileusis has become a popular type of refractive surgery for the correction of myopia worldwide. This study uses qualitative inquiry approaches to understand the motives and processes of patients' LASIK surgery decision making.

METHODS

A purposive sample of 45 patients who had decided to undergo LASIK was recruited. Our qualitative study used in-depth interviews and used content analysis to interpret the data.

RESULTS

Among 45 participants, 48.9% reported that career requirements were the most important reason for seeking LASIK surgery. The inconvenience of wearing glasses or lenses during activities of daily life was also a primary motive. Improving facial appearance was a main reason for female but not male respondents. Potential complications of spectacles and contact lenses in addition to maturation of LASIK technology were also reported motives to seek surgery. Participants gave multiple, overlapping reasons for LASIK surgery.

CONCLUSIONS

These findings suggest that motives to seek LASIK surgery are not only a desire to correct refractive error but also social factors and confidence in improved surgical technology. The implications for clinicians are to be aware of these multiple motives for LASIK to improve the quality and effectiveness of health services for myopia patients.

Comparing Patient-Reported Outcomes of Laser In Situ Keratomileusis and Small-Incision Lenticule Extraction: A Review

PURPOSE

Laser in situ keratomileusis (LASIK) and small-incision lenticule extraction (SMILE) are popular refractive surgeries. The objective refractive outcomes of LASIK and SMILE have been studied extensively; both procedures have comparable safety, efficacy, and predictability. However, owing to various psychosocial factors, refractive patients may report dissatisfaction despite good postoperative vision. Hence the importance of studies on subjective patient-reported outcomes. This review discusses the role of psychometric-technique-based validated questionnaires when evaluating subjective outcomes. It also summarizes the literature on patient-reported outcomes for LASIK and SMILE.

DESIGN

A literature search was performed on PubMed database to identify studies that have assessed patient-reported outcomes for LASIK and SMILE.

RESULTS

Several studies have looked into patient-reported outcome measures for LASIK, but the number of equivalent studies for SMILE is limited. Questionnaires (validated and non-validated) are used to evaluate patient-reported outcomes. Validated questionnaires are designed based on psychometric techniques, such as Classic Test Theory, Item Response Theory, and Rasch analysis. The Quality of Life Impact of Refractive Correction (QIRC) questionnaire, a validated questionnaire administered to both LASIK and SMILE patients, suggests that both groups have comparable vision-related quality of life in the first few months postoperatively; but SMILE might confer a slight advantage in the later postoperative period (postoperative month 6).

CONCLUSIONS

Future LASIK-SMILE comparative studies utilizing standardized validated questionnaires for patient-reported outcome measures with longer follow-up durations would be a welcome contribution to this important aspect of refractive surgery.

Comparison of Wavefront-Optimized Ablation and Topography-Guided Contoura Ablation With LYRA Protocol in LASIK

PURPOSE

To compare the refractive outcomes and aberration data analysis of wavefront-optimized (WFO) ablation and topography-guided Contoura ablation (TGCA) (Contoura on the WaveLight laser; WaveLight GmbH, Erlangen, Germany) in patients who had laser-assisted in situ keratomileusis (LASIK) for myopia or myopic astigmatism.

METHODS

In this comparative contralateral eye study, patients who underwent LASIK with TGCA in one eye and with WFO ablation in the fellow eye were analyzed. Aberration measurements and corneal topography were analyzed using the WaveLight Oculyzer II diagnostic device (Alcon Laboratories, Inc., Fort Worth, TX). Total corneal higher order aberrations (HOAs) including vertical and oblique astigmatism (Z² ₂, Z² _-2), coma (Z³ ₁, Z³ _-1), trefoil (Z³ ₃, Z³ _-3), spherical aberration, and Q value were analyzed. These measurements were taken preoperatively and 3 months postoperatively.

RESULTS

This study comprised 32 patients. There were no significant differences between both procedures according to postoperative uncorrected and corrected distance visual acuity values, refractive errors, and manifest refraction spherical equivalents within ±0.50 diopters (D) of emmetropia (P > .05). The preoperative corneal HOAs and Q values were also similar between the groups (P > .05). At 3 months postoperatively, the vertical and horizontal coma values in the WFO ablation group were statistically significantly higher compared to the TGCA group (P = .013 and .020, respectively). Less stromal tissue was ablated in the TGCA group compared to the WFO ablation group (P < .001).

CONCLUSIONS

Although WFO ablation and TGCA protocols had statistically similar visual outcomes, the TGCA protocol was associated with a significantly lower induction in vertical and horizontal coma and smaller amount of tissue ablation compared to WFO ablation. [J Refract Surg. 2019;35(4):222-229.].

Prospective Randomized Multicenter Comparison of the Clinical Outcomes of V4c and V5 Implantable Collamer Lenses: A Contralateral Eye Study

Purpose

To compare the visual and refractive outcomes and night vision performance questionnaire results between V4c and V5 implantable Collamer lenses in a prospective, randomized, multicenter study.

Settings

Four refractive surgery centers.

Design

Prospective randomized multicenter single-masked comparative study.

Methods

Twenty-three patients were enrolled in this study. A conventional V4c model (EVO Visian ICL) was implanted in one eye, and a V5 model (EVO+ Visian ICL), which has a larger optic diameter than the V4c model, was implanted in the contralateral eye. The uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were evaluated before and 6 months after surgery. At 6 months after surgery, a questionnaire on night vision disturbances was administered. The efficacy, safety, and predictability of the two implanted ICL models were compared.

Results

There were no significant differences in the postoperative UDVA and CDVA between the two ICL models. The mean efficacy indexes for the V4c and V5 lenses were 1.16 ± 0.22 and 1.03 ± 0.23, respectively. The mean safety indexes of the V4c and V5 lenses were 1.21 ± 0.20 and 1.19 ± 0.20, respectively. The night vision performance questionnaire revealed that 7 patients (37%) noticed a difference in visual performance between the eyes, and all of them reported that they could see better at night with the V5-implanted eye compared with the V4c-implanted eye.

Conclusion

The V4c and V5 ICL models achieved similar visual and refractive outcomes, whereas the V5 model showed a possible advantage in reducing night vision disturbances.

Comparison of simulated keratometric changes following wavefront-guided and wavefront-optimized myopic laser-assisted in situ keratomileusis

Purpose

The aim of the study was to determine and compare the relationship between change in simulated keratometry (K) and degree of refractive correction in wavefront-guided (WFG) and wavefront-optimized (WFO) myopic laser-assisted in situ keratomileusis (LASIK).

Methods

A total of 51 patients were prospectively randomized to WFG LASIK in one eye and WFO LASIK in the contralateral eye at the Byers Eye Institute, Stanford University. Changes in simulated K and refractive error were determined at 1 year post-operatively. Linear regression was employed to calculate the slope of change in simulated K (ΔK) for change in refractive error (ΔSE). The mean ratio (ΔK/ΔSE) was also calculated.

Results

The ratio of ΔK to ΔSE was larger for WFG LASIK compared to WFO LASIK when comparing the slope (ΔK/ΔSE) as determined by linear regression (0.85 vs 0.83, p = 0.04). Upon comparing the mean ratio (ΔK/ΔSE), subgroup analysis revealed that ΔK/ΔSE was larger for WFG LASIK for refractive corrections of >3.00 D and >4.00 D (0.89 vs 0.83; p = 0.0323 and 0.88 vs 0.83; p = 0.0466, respectively). Both linear regression and direct comparison of the mean ratio (ΔK/ΔSE) for refractive corrections <4.00 D and >4.00 D revealed no difference in ΔK/ΔSE between smaller and larger refractive corrections.

Conclusion

WFO LASIK requires a smaller amount of corneal flattening compared to WFG LASIK for a given degree of refractive correction. For both, there was no significant difference in change in corneal curvature for a given degree of refractive error between smaller and larger corrections.

Reducing starbursts in highly aberrated eyes with pupil miosis

PURPOSE

To test the hypothesis that marginal ray deviations determine perceived starburst sizes, and to explore different strategies for decreasing starburst size in highly aberrated eyes.

METHODS

Perceived size of starburst images and visual acuities were measured psychophysically for eyes with varying levels of spherical aberration, pupil sizes, and defocus. Computationally, we use a polychromatic eye model including the typical levels of higher order aberrations (HOAs) for keratoconic and post-LASIK eyes to quantify the image quality (the visually weighted Strehl ratio derived from the optical transfer function, VSOTF) with different pupil sizes at both photopic and mesopic light levels.

RESULTS

For distance corrected post-LASIK and keratoconic eyes with a night-time pupil (e.g., 7 mm), the starburst diameter is about 1.5 degrees (1 degree for normal presbyopic eyes), which can be reduced to ≤0.25 degrees with pupil sizes ≤3 mm. Starburst size is predicted from the magnitude of the longitudinal spherical aberration. Refracting the eye to focus the pupil margin also removed starbursts, but, unlike small pupils, significantly degraded visual acuity. Reducing pupil diameter to 3 mm improved image quality for these highly aberrated eyes by about 2.7 ×  to 1.7 ×  relative to the natural pupils when light levels were varied from 0.1 to 1000 cd m^-2 , respectively.

CONCLUSION

Subjects with highly aberrated eyes observed larger starbursts around bright lights at night predictable by the deviated marginal rays. These were effectively attenuated by reducing pupil diameters to ≤3 mm, which did not cause a drop in visual acuity or modelled image quality even at mesopic light levels.

Q-optimized Algorithms: Theoretical Analysis of Factors Influencing Visual Quality After Myopic Corneal Refractive Surgery

PURPOSE

To model the effect of pupil size, optical zone, and initial myopic level on the retinal image quality after Q-optimized myopic corneal refractive surgery.

METHODS

Different Q-optimized and paraxial Munnerlyn algorithms were tested using a schematic myopic eye model to analyze the optical quality of the final retinal image for initial myopic errors from -1.00 to -7.00 diopters (D). Different optical zones (5.5, 6, and 6.5 mm in diameter) and two pupil diameters (5 and 7 mm, mesopic-scotopic conditions) were included in the comparison. Modulation transfer function (MTF) and area under the MTF from 0 to 60 cycles per degree (MTFa) were calculated by ray tracing to evaluate this retinal image quality.

RESULTS

The Q-optimized algorithm with Q = -0.45 provided the highest MTF and MTFa results for myopic corrections less than -5.00 D. For refractive errors greater than -5.00 D, Q = -0.26 provided the highest MTF and MTFa results.

CONCLUSIONS

Q-optimized algorithms improve the visual outcomes with respect to the paraxial Munnerlyn algorithm for myopic corneal surgery. The results show that the Q value that optimizes the results of the Q-optimized algorithm depends on the degree of myopia to correct and the size of the pupil. [J Refract Surg. 2016;32(9):612-617.].

Single-step transepithelial photorefractive keratectomy in high myopia: qualitative and quantitative visual functions

AIM

To investigate quantitative and qualitative optical outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) in high myopia.

METHODS

In a prospective interventional case-series, 30 eyes with high myopia (-6.00 to -8.75 D) with (up to -3.00 D) or without astigmatism were enrolled from Bina Eye Hospital, Tehran, Iran. One-step TransPRK was performed with aberration-free aspherical optimized profile and SCHWIND AMARIS 500 laser. One-year follow-up results for refraction, visual acuities, vector analysis, ocular wave-front (OWF) and corneal wave-front (CWF) higher order aberrations (HOA), contrast sensitivity (CS), and post-operative haze were assessed.

RESULTS

After the surgery, both photopic and mesopic CSs significantly improved (both P<0.001). We detected significant induction of OWF coma and trefoil (P<0.001 for both) HOAs; CWF coma (P=0.002), spherical (P<0.001), and tetrafoil (P=0.003) HOAs in 6 mm analysis diameter; and CWF trefoil (P=0.04) HOA in 4 mm analysis diameter. The range of mean induction observed for various HOAs was 0.005-0.11 µm. The 86.7% of eyes reached an uncorrected distance visual acuity of 20/20 or better; 96.7% of eyes were within ±0.5 D of targeted spherical refraction. In vector analysis, mean correction index value was 1.03 and mean index of success was 0.22. By 12mo after the operation, no eye lost any number of corrected distance visual acuity lines. We detected no corneal haze greater than 1⁺ throughout the follow-up.

CONCLUSION

Our findings show promising effects of single-step TransPRK on quality of vision in high myopic eyes. It also improves refraction and visual acuity.

Factors Predicting the Need for Retreatment After Laser Refractive Surgery

PURPOSE

To identify the potential risk factors that increase the likelihood of requiring retreatment after refractive surgery.

METHODS

This retrospective study included patients who underwent laser in situ keratomileusis or photorefractive keratectomy between January 2005 and December 2012 at the Care-Vision Laser Centers, Tel-Aviv, Israel. Patients were divided into 2 groups according to whether they underwent additional refractive surgery (retreatment) during the study period.

RESULTS

Overall, 41,504 eyes (n = 21,313) were included in the final analysis of this study. Throughout the study period, there was a significant reduction in the 2-year annual retreatment rates with a decline from 4.52% for primary surgeries done in 2005 to 0.18% for surgeries performed in 2012 (quadratic R = 0.96, P < 0.001). The retreatment group had significantly higher preoperative age, maximum keratometric power, sphere, cylinder, and better best-corrected visual acuity. They were more likely to have preoperative hyperopia, photorefractive keratectomy as opposed to laser in situ keratomileusis, intraoperative higher humidity conditions and lower temperature, and higher ablation depths. Significant differences in retreatment rates were found between the 5 high-volume surgeons (>1500 procedures performed) ranging from 0.48 to 3.14% (P < 0.0001). Multiple logistic regression analysis demonstrated that age, astigmatism, hyperopia, temperature, and surgeon's experience all significantly affected the need for retreatment.

CONCLUSIONS

The following factors significantly increase the need for refractive retreatment: older preoperative age, higher degrees of astigmatism, hyperopia, colder operating room temperature, and less surgeon experience. Some of these factors may be incorporated into nomograms to reduce future retreatment rates.

Comparison of visual acuity of the patients on the first day after sub-Bowman keratomileusis or laser in situ keratomileusis

AIM

To compare recovery of the visual acuity in patients one day after sub-Bowman keratomileusis (SBK) or laser in situ keratomileusis (LASIK).

METHODS

Data from 5923 eyes in 2968 patients that received LASIK (2755 eyes) or SBK (3168 eyes) were retrospectively analyzed. The eyes were divided into 4 groups according to preoperative spherical equivalent: between -12.00 to -9.00 D, extremely high myopia (n=396, including 192 and 204 in SBK and LASIK groups, respectively); -9.00 to -6.00 D, high myopia (n=1822, including 991 and 831 in SBK and LASIK groups, respectively), -6.00 to -3.00 D, moderate myopia (n=3071, including 1658 and 1413 in SBK and LASIK groups, respectively), and -3.00 to 0.00 D, low myopia (n=634, including 327 and 307 in SBK and LASIK groups, respectively). Uncorrected logMAR visual acuity values of patients were assessed under standard natural light. Analysis of variance was used for comparisons among different groups.

RESULTS

Uncorrected visual acuity values were 0.0115±0.1051 and 0.0466±0.1477 at day 1 after operation for patients receiving SBK and LASIK, respectively (P<0.01); visual acuity values of 0.1854±0.1842, 0.0615±0.1326, -0.0033±0.0978, and -0.0164±0.0972 were obtained for patients in the extremely high, high, moderate, and low myopia groups, respectively (P<0.01). In addition, significant differences in visual acuity at day 1 after operation were found between patients receiving SBK and LASIK in each myopia subgroup.

CONCLUSION

Compared with LASIK, SBK is safer and more effective, with faster recovery. Therefore, SBK is more likely to be accepted by patients than LASIK for better uncorrected visual acuity the day following operation.

Effect of postoperative keratometry on quality of vision in the postoperative period after myopic wavefront-guided laser in situ keratomileusis

PURPOSE

To determine whether postoperative keratometry is a predictor of patient-reported satisfaction and night-vision phenomena after wavefront-guided myopic laser in situ keratomileusis (LASIK).

SETTING

Optical Express, Glasgow, United Kingdom.

DESIGN

Retrospective case series.

METHODS

Myopic eyes treated with wavefront-guided LASIK were analyzed in this study. All patients completed pre-operative and 1-month postoperative questionnaires, in which the satisfaction with visual outcomes and pre-operative and postoperative night-vision symptoms (glare, halos, starburst, ghosting/double-vision) were rated. Multivariate regression analysis was performed to determine factors associated with questionnaire outcomes.

RESULTS

This study evaluated 8672 myopic eyes of 4602 patients. The mean pre-operative manifest spherical equivalent was -3.72 diopters (D) ± 2.00 (SD) (range -0.50 to -11.00 D) and the mean pre-operative keratometry (K) value was 43.64 ± 1.43 D (38.38 to 49.00). At 1 month after surgery, 93.7% and 99.1% of eyes were within 0.50 D and 1.00 D of emmetropia, and 94.6% and 98.3% of eyes achieved monocular and binocular uncorrected-distance visual acuity(UDVA) of 20/20 or better, respectively. There were 48.7% of eyes that had the flat corneal meridian (minimum K) of 40.0 D or less. Although postoperative keratometry was a significant predictor of patient-reported satisfaction and the change in halo reports in the regression analysis, its relative contribution was very low and accounted for less than 0.50% of the variance explained by either model. Postoperative keratometry was not a significant predictor of a change in reports of glare, starburst, and ghosting or double vision.

CONCLUSION

In this large cohort of patients, postoperative keratometry played a minimal and clinically insignificant role in predicting post-LASIK halo visual phenomena and patient-reported satisfaction.

FINANCIAL DISCLOSURE

Dr. Schallhorn is a consultant to Abbott Medical Optics and Zeiss and a Global Medical Director for Optical Express. None of the other authors have a financial or proprietary interest in the products and materials presented in this paper.

Dry Eye Disease following Refractive Surgery: A 12-Month Follow-Up of SMILE versus FS-LASIK in High Myopia

Purpose. To compare dry eye disease following SMILE versus FS-LASIK. Design. Prospective, nonrandomised, observational study. Patients. 90 patients undergoing refractive surgery for myopia were included. 47 eyes underwent SMILE and 43 eyes underwent FS-LASIK. Methods. Evaluation of dry eye disease was conducted preoperatively and at 1, 3, 6, and 12 months postoperatively, using the Salisbury Eye Evaluation Questionnaire (SEEQ) and TBUT. Results. TBUT reduced following SMILE at 1 and 3 months (p < 0.001) and at 1, 3, and 6 months following FS-LASIK (p < 0.001). TBUT was greater following SMILE than FS-LASIK at 3, 6, and 12 months (p < 0.001, p < 0.001, and p = 0.009, resp.). SEEQ scores increased (greater symptoms) following SMILE at 1 month (p < 0.001) and 3 months (p = 0.003) and at 1, 3, and 6 months following FS-LASIK (p < 0.001). SMILE produced lower SEEQ scores (fewer symptoms) than FS-LASIK at 1, 3, and 6 months (p < 0.001). Conclusion. SMILE produces less dry eye disease than FS-LASIK at 6 months postoperatively but demonstrates similar degrees of dry eye disease at 12 months.

Patient and surgeon experience during laser in situ keratomileusis using 2 femtosecond laser systems

PURPOSE

To describe the subjective experience of patients and surgeons during laser in situ keratomileusis (LASIK) using the Intralase 60 kHz or the Visumax 500 kHz femtosecond laser.

SETTING

Singapore National Eye Centre, Singapore.

DESIGN

Prospective randomized clinical study.

METHODS

In myopic patients, LASIK was performed with the corneal flap created using the 60 kHz laser in 1 eye and the 500 kHz laser in the contralateral eye. Postoperatively, patients completed a standardized validated questionnaire about their subjective intraoperative experiences (eg, light perception, pain, fear). Surgeons reported their intraoperative experiences and preferences.

RESULTS

Loss of light perception occurred in 50.0% of 60 kHz laser cases and 0% of 500 kHz laser cases during docking and in 63.0% and 0% of cases, respectively, during laser flap creation (P < .0001). The mean pain score with the 60 kHz laser was significantly higher during docking (P < .0001) but not during laser flap cutting (P = .006). Subconjunctival hemorrhage occurred in 67.4% of eyes with the 60 kHz laser and in 2.2% of eyes with the 500 kHz laser (P < .0001). The 500 kHz laser was preferred by 78.3% of patients, while 21.7% preferred the 60 kHz laser (P < .0001). The surgeons preferred the 60 kHz laser in 50.0% of cases and the 500 kHz laser in 8.7% (P < .0001); 41.3% had no preference.

CONCLUSIONS

Patients preferred surgery with the 500 kHz laser with no loss of light perception, less pain, less fear, and less subconjunctival hemorrhage. Surgeons preferred the 60 kHz laser.

Pupil size and LASIK: a review

PURPOSE

To provide a literature review on the evidence both for and against pupil size as an independent predictor of adverse visual outcomes after LASIK.

METHODS

Peer-reviewed publications on the effect of pupil size on LASIK outcomes since 2002 are reviewed. Particular attention was paid to the following attributes of each publication: type of study, number of patients or eyes, mean age, mean level of myopia, mean pupil size, testing conditions, ablation zone diameter, presence or absence of blend zones, and mean follow-up period.

RESULTS

Among the 19 studies examined, none correlates a persistent relationship between pupil size and night vision complaints (NVCs) beyond 3 months when LASIK was performed with a 6.0-mm optical zone or larger ablation. The studies that did explicitly determine a correlation either included some or all patients with ablation zones smaller than 6.0 mm or did not specify ablation diameter at all. Among the studies that had drawn more mixed conclusions, the studies either covered short follow-up intervals (1 to 3 months) or showed a progressive improvement in NVCs over time in a relatively small patient cohort.

CONCLUSIONS

As keratorefractive technology continues to evolve, the role of pupil size warrants further investigation; however, based on the literature reviewed herein, modern LASIK has negated the role of the low light pupil in predicting adverse visual outcomes after LASIK outside of the early postoperative period.

Risk factors associated with night vision disturbances after phakic intraocular lens implantation

PURPOSE

To investigate the incidence and severity of night vision disturbances after implantable collamer lens surgery and to analyze the risk factors.

DESIGN

Retrospective, noncomparative study.

METHODS

Medical charts from 50 eyes of 25 patients who underwent implantable collamer lens implantation were retrospectively reviewed. The incidence and severity of night vision disturbances were evaluated using questionnaires administered 6 months after surgery. Univariate simple and multiple logistic regression analyses were used to detect risk factors associated with postoperative night vision disturbances. Potential risk factors included in the analysis were keratometric value, anterior chamber depth, postoperative residual refractive error, higher-order aberrations, preoperative and postoperative mesopic pupil size, the difference between preoperative and postoperative mesopic pupil size, the difference between mesopic pupil size and implantable collamer lens optic zone diameter, white-to-white diameter, sulcus-to-sulcus diameter, and postoperative implantable collamer lens vaulting. The power, size, optic zone diameter, and toricity of the implantable collamer lens were also included as variables.

RESULTS

The incidence of night vision disturbances was 34.0% for halos and 26.0% for glare. Halos were found to be significantly related to the difference between mesopic pupil size and implantable collamer lens optic zone diameter (P = .013), white-to-white diameter of the cornea (P = .028), and implantable collamer lens optic zone diameter (P = .030). For glare, toricity of the implantable collamer lens was revealed as a significant risk factor (P = .047).

CONCLUSIONS

Although not severe, the incidence of night vision disturbances after implantable collamer lens implantation was not negligible. Possible risk factors for night vision disturbances include implantable collamer lens optic zone diameter, the difference between mesopic pupil size and implantable collamer lens optic zone diameter, and white-to-white diameter of the cornea for causing halos, and the toricity of the implantable collamer lens for causing glare.

Small optical zones with aspheric profiles in laser refractive surgery for myopia: a surgical outcome and patient satisfaction study

PURPOSE

To assess the outcomes of small optical zone (OZ) ablations used in conjunction with large transition zones (TZ) and a highly aspheric treatment profile.

METHODS

Interventional case series of 39 consecutive patients with myopia or myopic astigmatism. Patient data included pre and postoperative refraction and visual acuities, laser treatment settings and pre and postoperative corneal topography as well as questionnaire responses about the use of glasses and the quality of vision postoperatively.

RESULTS

The mean preoperative spherical equivalent was -4.50±2.11 dioptres (D) and the mean OZ and TZ diameters were 4.5±0.5mm and 8.1±0.4mm, respectively. The mean patient age was 40.7±10.4 years. Manifest spherical refraction was within ±0.5D in 87% of patients (±1.0D in 99%) and cylindrical refraction within 0.5D in 79% (≤1.0D in 95%). The need to wear distance glasses postoperatively was associated with dissatisfaction with the quality of daytime vision (p=0.05) and unhappiness with night vision was associated with symptoms of halos (p=0.03) and starbursts (p=0.02). The proportion of patients reporting symptoms of dysphotopsias included: ghosting 0%; glare 2%; halos 10%; and starbursts 15%. There was a significant difference in the measured mean effective OZ diameter (4.8±0.3mm) compared to the mean programmed OZ (4.5±0.5mm, p=0.00).

CONCLUSIONS

Small ablation zones, when used in conjunction with a large diameter TZ, do not lead to a greater incidence of unwanted visual phenomena over that reported by many studies with larger OZs.

Satisfaction level of physicians who have undergone corneal refractive surgery

Purpose

To evaluate the levels of satisfaction among physicians who have undergone corneal refractive surgery.

Methods

This study included 212 eyes of 107 consecutive patients who underwent laser in situ keratomileusis or laser sub-epithelial keratomileusis surgery. Patients were divided into two groups: one group of physicians and one group of other healthcare workers (HCWs). The physicians' group was also subdivided into two different groups: surgeons or doctors using microscopes and medical physicians. The main outcome measures were scale scores obtained by using the Visual Function Index-14 questionnaires; uncorrected distance visual acuity (UDVA), residual spherical equivalent (SE), optical zone diameter, and residual corneal thickness were also compared between the groups.

Results

No significant differences in preoperative parameters, with the exception of the ratio of types of refractive surgery, were noted between the physicians and the HCWs group. Additionally, no differences between the groups were noted in the postoperative UDVA, residual SE, optical zone diameter, residual corneal thickness, and level of satisfaction. When comparing the two subgroups of physicians, the differences in satisfaction rates were not statistically significant, even in terms of the performance of delicate manual work.

Conclusions

No statistically significant differences in the clinical outcomes and satisfaction scores were detected after surgery between the physicians and HCWs groups, nor were any significant differences detected between the surgeons and medical physicians groups. Corneal refractive surgery can conceivably be recommended even for physicians who perform intensive near vision-dependent activities and delicate operations.

Comparison of work-related symptoms and visual contrast sensitivity between employees at a severely water-damaged school and a school without significant water damage

BACKGROUND

The National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation (HHE) of a water-damaged school in New Orleans (NO), Louisiana. Our aim in this evaluation was to document employee health effects related to exposure to the water-damaged school, and to determine if VCS testing could serve as a biomarker of effect for occupants who experienced adverse health effects in a water-damaged building.

METHODS

NIOSH physicians and staff administered a work history and medical questionnaire, conducted visual contrast sensitivity (VCS) testing, and collected sticky-tape, air, and dust samples at the school. Counting, culturing, and/or a DNA-based technology, called mold-specific quantitative PCR (MSQPCR), were also used to quantify the molds. A similar health and environmental evaluation was performed at a comparable school in Cincinnati, Ohio which was not water-damaged.

RESULTS

Extensive mold contamination was documented in the water-damaged school and employees (n = 95) had higher prevalences of work-related rashes and nasal, lower respiratory, and constitutional symptoms than those at the comparison school (n = 110). VCS values across all spatial frequencies were lower among employees at the water-damaged school.

CONCLUSIONS

Employees exposed to an extensively water-damaged environment reported adverse health effects, including rashes and nasal, lower respiratory, and constitutional symptoms. VCS values were lower in the employees at the water-damaged school, but we do not recommend using it in evaluation of people exposed to mold. Am. J. Ind. Med. 55:844-854, 2012. This article is a U.S. Government work and is in the public domain in the USA.

Analysis of optical side-effects of fs-laser therapy in human presbyopic lens simulated with modified contact lenses

BACKGROUND

In a single-blinded study, optical side-effects of a potential femtosecond (fs)-laser therapy in presbyopic human lenses were tested. Simulation of this therapy was carried out by applying fs-laser patterns into standard contact lenses (CL).

METHODS

In the first part of the study, the influence of the numerical aperture on optical side-effects was investigated by comparing a typical fs-LASIK configuration to a fs-presbyopia treatment (n = 11). The second part focused on a possible improvement of visual performance by comparing a regular grid pattern to a randomly chosen spacing of the laser spots (n = 16). Visual acuity was measured with ETDRS charts, contrast sensitivity with F.A.C.T. charts and mesopic vision with Mesotest II. Forward scattered light was measured with the C-Quant (both instruments: Oculus Optikgeräte GmbH, Germany). A questionnaire detected subjective quality of vision. Differences between laser-treated and untreated CL and among the modifications were analyzed.

RESULTS

The laser-treated and standard CL indicated no significant difference in visual acuity, contrast sensitivity and mesopic vision without glare. While wearing modified lenses with a regular grid, quality of vision decreased significantly by means of mesopic vision with glare and subjective straylight. These modifications also caused an impairment of subjective quality of vision. In contrast, there was no significant difference between the random pattern and standard CL.

CONCLUSION

The increase of optical side-effects was reproducibly dependent on the geometry of the laser-structure. A randomized grid induced the least limitation. The study results are useful for planning possible laser-patterns in fs-laser therapy of the presbyopic lens.

Long-term outcome of epi-LASIK for high myopia

PURPOSE

To evaluate the long-term outcomes of epipolis laser-assisted in situ keratomileusis (epi-LASIK) for high myopia.

METHODS

High myopic patients who underwent epi-LASIK during 2004 and 2005 were included in this study. Epi-LASIK was performed with an automatically rotational epikeratome (KM-5000D). Postoperative visual acuity, manifest refraction, and haze formation were assessed 3 mo, 6 mo, 1 y, and 3 y after surgery. Results were compared by dividing patients into 2 groups according to preoperative mean refractive spherical equivalent (MRSE): group A (≥-6 D to -10 D; group B ≥-10 D). The differences within groups were analyzed using mixed model for continuous variables. The differences between groups were analyzed using t test or rank sum test for continuous variables, and Pearson χ² or Fisher exact probabilities for categorical variables.

RESULTS

A total of 20 patients (33 eyes) were followed up for more than 3 years with 17 eyes in group A (MRSE -8.15 ± 1.41 D) and 16 eyes in group B (MRSE -12.95 ± 2.91 D). While postoperative refraction regression occurred in both groups, it was more prominent in group B (p<0.05). The long-term predictability is good in group A with 14 eyes (82.35%) within ±1 D of attempted correction at 3 years while the percentage in group B was 18.75%. The efficacy index was significantly different between the 2 groups (p<0.05): 0.84 ± 0.29 for group A and 0.61 ± 0.47 for group B at 3 years. The safety index was above 1.0 at each timepoint in both groups. Haze was at low level and faded with time after epi-LASIK.

CONCLUSIONS

Epi-LASIK had a satisfactory long-term effect for high myopia of less than -10 D. Myopic regression limited the satisfaction of epi-LASIK in eyes with myopia of more than -10.0 D.

Contrast sensitivity after zyoptix tissue saving LASIK and standard LASIK for myopia with 6-month followup

This control-matched comparative study evaluated changes in contrast sensitivity after Zyoptix tissue-saving (TS) LASIK and Planoscan standard LASIK (Technolas 217z, Bausch & Lomb) for myopia 6 months postoperatively. 102 TS LASIK-treated eyes were matched with 102 standard LASIK-treated eyes (divided into low, moderate, and high groups). There were no significant differences in refraction outcomes between the groups postoperatively. In high group, a significant reduction in contrast sensitivity after TS LASIK was found at high spatial frequencies (P < .05) under photopic conditions and at middle to high spatial frequencies (P < .05) under mesopic conditions. And significant reduction was also found in standard LASIK at high spatial frequency (P < .05) under mesopic conditions. The reduction was significantly lower in TS LASIK than that in standard LASIK at high spatial frequencies (P < .05) under mesopic conditions. TS LASIK was prone to reduce mesopic contrast sensitivity of high myopia at high spatial frequencies.

Comparison of simulated keratometric changes induced by custom and conventional laser in situ keratomileusis after myopic ablation: retrospective chart review

PURPOSE

To determine the relationship between the achieved refractive change and the change in simulated keratometry (K) after myopic laser situ keratomileusis (LASIK) and compare this relationship between custom and conventional treatments.

SETTING

Department of Ophthalmology, University of California, Davis, Sacramento, California, and John A. Moran Eye Center, Salt Lake City, Utah, USA.

METHODS

The change in simulated K and the refractive change induced by custom myopic LASIK and conventional LASIK were determined. The relationship between the variables was analyzed by regression methods.

RESULTS

Custom treatment was performed in 106 eyes and conventional treatment in 224 eyes. Simple linear regression analysis did not fit the clinical observation when the refractive change was less than 2.00 diopters (D) of myopic correction with both treatments. Under the linear model and nonlinear model, each unit of refractive change yielded a greater change in corneal topographic power with custom treatment than with conventional treatment. With both treatments, the rate of change in simulated K was not constant and was much more variable with lower amounts of correction. The relationship was more constant and linear with larger amounts of refractive correction.

CONCLUSIONS

The relationship between the measured change in simulated K and the induced refractive change better fit a nonlinear relationship with smaller amounts of refractive correction in custom LASIK and conventional LASIK. Under all forms of analysis, custom treatments yielded a greater per-unit change in corneal curvature than conventional treatments, especially for refractive corrections of 4.00 D and higher.

A comparison of corneal cellular responses after 213-nm compared with 193-nm laser photorefractive keratectomy in rabbits

PURPOSE

Corneal refractive surgery is typically performed using a 193-nm excimer laser. However, a recently developed 213-nm solid-state (5th harmonic) Nd:YAG laser presents some practical and user safety advantages, although the biological impact of using this wavelength remains poorly characterized. Here, we provide in vivo and in vitro comparisons of the corneal cellular outcomes after irradiation with 213 and 193 nm wavelengths.

METHODS

New Zealand White rabbits underwent photorefractive keratectomy with -5 diopters and a 6.5-mm optical zone and studied at time points up to 1 year. The development of haze was examined ophthalmologically and by detecting myofibroblasts immunohistochemically. Cell death was quantified using a terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL) assay, and the number of stromal keratocytes undergoing apoptosis estimated histologically. Superoxide dismutase activity was estimated in vitro by enzyme-linked immunosorbent assay in irradiated rabbit corneal keratocytes.

RESULTS

Our results demonstrate subtle differences in the cellular outcomes after irradiation with 213- and 193-nm lasers, despite similar degrees of corneal haze developing in both treatment groups. In vivo, the 213-nm laser results in more stable stromal cell numbers, implying a more predictable ablation outcome. In vitro, higher levels of superoxide dismutase in corneal keratocytes irradiated with 213 nm compared with 193 nm wavelengths suggest a better endogenous protection against free radicals induced by laser surgery.

CONCLUSIONS

The more favorable cellular responses after irradiation with 213 nm compared with 193 nm wavelengths are consistent with good clinical outcomes previously reported. Ablation with a 213 nm wavelength may result in better wound healing, leading to a more reliable correction of refractive errors.

Patient-centered treatment goals for pelvic floor disorders: association with quality-of-life and patient satisfaction

OBJECTIVE

We sought to determine the relationship of patient-centered goal achievement in pelvic floor disorder (PFD) treatment to PFD-specific quality-of-life (QOL), depression, health status, and patient satisfaction.

STUDY DESIGN

Ninety women with PFD identified up to 5 goals for treatment and reported their level of goal attainment (-2 to +2) at 1.5, 3, 6, and 12 months; completed the Incontinence Impact Questionnaire, Urogenital Distress Inventory, Incontinence Quality-of-Life Scale, Patient Health Questionnaire, and Short Form-12 Health Survey; and indicated their satisfaction with treatment.

RESULTS

Twelve-month mean goal attainment was moderately correlated with PFD-specific measures of QOL (r range, -0.40 to 0.55; P < .05) but less strongly with depression and general health status (r range, -0.27 to 0.28). Twelve-month goal attainment differed significantly among those who were completely satisfied (1.6 +/- 0.5), very satisfied (1.2 +/- 0.6), satisfied (0.4-1.0), or not satisfied (-0.5 +/- 0.9; F = 24.2; P < .01). Earlier follow-up results were similar.

CONCLUSION

PFD treatment goal attainment is associated with improved condition-specific QOL and patient satisfaction.

Patient satisfaction and visual symptoms after wavefront-guided and wavefront-optimized LASIK with the WaveLight platform

PURPOSE

To investigate patient satisfaction and visual symptoms after wavefront-guided LASIK.

METHODS

A prospective, randomized, double-masked, controlled study comprised 200 eyes of 100 young patients who underwent LASIK for myopia and astigmatism. Patients were randomly divided into two different treatment groups: standard ablation using wavefront-optimized profiles (wavefront-optimized group) and aberration customized aspheric treatment ablation (customized group) using the WaveLight ALLEGRETTO platform. Patients were asked to complete questionnaires regarding reasons for surgery, satisfaction, and visual symptoms. Patients were followed for 6 months.

RESULTS

The most frequent motivating factor for surgery was to improve uncorrected visual acuity (UCVA) in the wavefront-optimized and customized groups (both 100%), followed by freedom from spectacles (86.9% vs 96.3%). At 6 months postoperatively, over 95% of patients in both groups reported their UCVA was as good as anticipated and they were satisfied with the surgery and would recommend the operation to a friend or family member. Satisfaction was not correlated with age, attempted refractive error, residual refractive error, postoperative UCVA, or root-mean-square higher order aberration. The rate of postoperative overall visual symptoms was reduced and the mean analog scores of the symptoms in both groups did not change significantly postoperatively (P > .05). The rate of visual symptoms such as glare (8.7% vs 7.4%), halo (0% vs 7.4%), and night driving difficulty (8.7% vs 3.7%) decreased after LASIK at 6 months postoperatively in the wavefront-optimized and customized groups, respectively.

CONCLUSIONS

Patient satisfaction was achieved in young myopic patients who underwent wavefront-guided and standard ("wavefront-optimized") LASIK. The rate of visual symptoms such as glare, halo, and night driving difficulty decreased postoperatively after both treatment protocols.

Active Eye-tracking Improves LASIK Results

PURPOSE

To study the advantage of active eye-tracking for photorefractive surgery.

METHODS

In a prospective, double-masked study, LASIK for myopia and myopic astigmatism was performed in 50 patients using the ALLEGRETTO WAVE version 1007. All patients received LASIK with full comprehension of the importance of fixation during the procedure. All surgical procedures were performed by a single surgeon. The eye-tracker was turned off in one group (n = 25) and kept on in another group (n = 25). Preoperatively and 3 months postoperatively, patients underwent a standard ophthalmic examination, which included comeal topography.

RESULTS

In the patients treated with the eye-tracker off, all had uncorrected visual acuity (UCVA) of > or = 20/40 and 64% had > or = 20/20. Compared with the patients treated with the eye-tracker on, they had higher residual cylindrical astigmatism (P < .05). Those treated with the eye-tracker on achieved better UCVA and best spectacle-corrected visual acuity (P < .05). Spherical error and potential visual acuity (TMS-II) were not significantly different between the groups.

CONCLUSIONS

The flying-spot system can achieve a fair result without active eye-tracking, but active eye-tracking helps improve the visual outcome and reduces postoperative cylindrical astigmatism.

Measurement of pupil reactivity using fast pupillometry

Analysis of human eye pupil reactivity is a very valuable diagnostic method used mainly for evaluation of the condition of the autonomic nervous system and the visual system. The paper presents an experimental pupillometer built in the Institute of Physics of the Wroclaw University of Technology. The apparatus makes it possible to record and analyze pupillary light reflex and spontaneous changes in the pupil diameter during a session in the dark. The detector system used in the pupillometer allows us to record the pupil diameter at a rate of 90 Hz with a linear accuracy of 0.008 mm. In this paper, the proposed detection method, the principle of operation and calibration of the apparatus and the possibilities of the measurement system are presented.

Does Dilated Wavefront Aberration Measurement Provide Better Postoperative Outcome after Custom LASIK?

PURPOSE

To compare outcomes after custom LASIK based on non-pharmacologically dilated (natural mesopic pupil) and pharmacologically dilated wavefront aberration measurement.

DESIGN

Case-control study.

PARTICIPANTS AND CONTROLS

The study group included 81 myopic eyes from 81 patients (mean preoperative spherical equivalent [SE], -4.15+/-1.97 diopters [D]). The control group consisted of 87 myopic eyes from 87 patients (mean preoperative SE, -4.98+/-2.00 D).

METHODS

The 81-eye study cohort was treated based on nonpharmacological low mesopic dilated wavefront aberration measurement (Zywave aberrometer), and the postoperative outcome was compared with that of the control group of 87 eyes treated, based on pharmacologically dilated (2.5% neosynephrine) wavefront data, using the Zyoptix platform. The same nomogram was used for both groups, which adjusts sphere based on the amount of preoperative higher-order aberration. All eyes had a low mesopic pupil diameter of > or =6.3 mm without pharmaceutical intervention.

MAIN OUTCOME MEASURE

Postoperative 3-month visual acuity (VA), contrast sensitivity, and refractive error.

RESULTS

Of the non-pharmacologically dilated eyes (study) and pharmacologically dilated (control) eyes, 96.3% and 96.6%, respectively, attained postoperative uncorrected VA of 20/20 or better. Although 96.6% of the eyes were within the target SE of +/-0.50 D in the control group, 100% of the 81 study eyes were within an SE of +/-0.50 D postoperatively. The range of postoperative SE (-0.75 to +1 D) was slightly reduced among the study eyes (+/-0.50 D). Differences were not statistically significant.

CONCLUSIONS

When a low mesopic pupil dilates to > or =6.3 mm, pharmacological dilation with wavefront-guided ablation may provide no additional benefit with regard to spherical accuracy when compared with nonpharmacological wavefront-guided ablation. The use of the Rochester nomogram, which accounts for aberration interaction, provided excellent results with or without pharmacological dilation.

Measurement of Contrast Sensitivity and Glare Under Mesopic and Photopic Conditions Following Wavefront-guided and Conventional LASIK Surgery

PURPOSE

To compare contrast and glare vision in a prospective study of eyes treated using conventional and wavefront-guided LASIK surgery. The reproducibility of a glaremeter device used to quantitatively measure glare and halo was also determined.

METHODS

Ninety-two eyes of 46 patients underwent conventional LASIK surgery and 104 eyes of 52 patients underwent wavefront-guided LASIK surgery. Visual acuity, glare disability measured using a glaremeter, and contrast sensitivity assessed using a Pelli-Robson chart were measured monthly for 6 months postoperatively. Glaremeter testing was performed under both mesopic (5.4 +/- 0.4 cd/m2) and photopic (78.3 +/- 4.4 cd/m2) conditions. To evaluate the reproducibility of the glaremeter, 36 eyes of 18 nonoperated myopic patients were tested.

RESULTS

The coefficient of variation and the reliability coefficient for the glare test were 13.6% and 95.2%, respectively. The glaremeter showed that glare disability under mesopic conditions differed between conventional and wavefront-guided LASIK eyes over 6-month follow-up (907.5 +/- 491.5 vs 986.1 +/- 448.0 pixels preoperatively and 1717.1 +/- 521.2 vs 1407.8 +/- 411.3 pixels at 6 months, P<.0001). At 6 months, contrast sensitivity log values were 1.62 +/- 0.31 and 1.78 +/- 0.34 for conventional and wavefront-guided LASIK eyes, respectively (P=.010). The visual complaint score was lower in the wavefront-guided LASIK group (P=.0116).

CONCLUSIONS

Compared to conventional ablation, wavefront-guided ablation provided superior outcomes in terms of postoperative glare under mesopic conditions, subjective complaints, and contrast sensitivity. In addition, it appears the glaremeter can be used for clinical quantitative evaluation of glare and halo.

Functional outcome and patient satisfaction after Artisan phakic intraocular lens implantation for the correction of myopia

PURPOSE

To determine patient satisfaction after Artisan phakic intraocular lens (PIOL) implantation to correct myopia.

DESIGN

Non-comparative prospective case series.

METHODS

One hundred twenty eyes of 60 patients who had undergone Artisan PIOL implantation to correct myopia were analyzed. A validated questionnaire that consisted of 66 satisfaction items were self-administered by patients 12 months after surgery. Clinical parameters (PIOL decentration, the difference between pupil size and PIOL optical zone, and optical aberrations) were measured. Main outcome measures of satisfaction scale scores (global satisfaction, quality of uncorrected and corrected vision, night vision, glare, day and night driving) were analyzed. Correlations with clinical parameters were obtained.

RESULTS

After surgery, 98.3% of patients were satisfied, and 73.3% of patients considered their night vision to be the same or better; 44.1% of patients reported more bothersome glare. The night vision score correlated with spheric aberration (r = -0.303; P = .020). The glare score correlated with the difference between scotopic pupil size and PIOL optical zone (r = -0.280; P = .030) and vertical coma (r = -0.337; P = .009). The night driving score correlated with postoperative spheric equivalent (r = 0.375; P = .009), total root mean square aberrations (r = -0.337; P = .017), higher order root mean square aberrations (r = -0.313; P = .027), and vertical coma (r = -0.297; P = .036).

CONCLUSION

Overall satisfaction after Artisan PIOL implantation for myopia is excellent. The quality of night vision and night driving were related to scotopic pupil size, individual higher order aberrations, and residual refractive error.

[Optical quality after refractive corneal surgery]

Correction of myopia, hyperopia and astigmatism within its indicated margin by means of refractive corneal surgical procedures such as LASIK and surface ablation (e.g. PRK) is one of the standard procedures in ophthalmology. Now that advances in the fields of surgical techniques and the technical devices employed have further progressed in terms of safety and predictability, research also focuses on optical quality. "Optical quality" is not a clearly defined parameter, but can be captured indirectly by means of directly measured data. One has to start with the anatomical properties of the eye, which determine the optical images on the retinal level. The quality of the retinal image influences the eye's function, i.e. acuity and contrast perception. Finally, there is the subjective perception of the image we receive. "Optical quality" as such is reflected by the patient's evaluation of this image perception. Three phenomena are especially responsible for deterioration of the quality of the retinal image: diffraction, aberrations and dispersion. Some of the methods for measuring optical quality are subjective questionnaires, functional testing procedures for measuring visual acuity and contrast sensitivity, optical measuring procedures for the determination of optical quality, as well as biomicroscopy, aberrometry and corneal topography for assessing anatomical changes.

Outcome of simultaneous phakic implantable contact lens removal with cataract extraction and pseudophakic intraocular lens implantation

PURPOSE

To assess the outcome of simultaneous implantable contact lens (ICL) removal and cataract extraction with pseudophakic intraocular lens (IOL) implantation.

SETTING

CODET Aris Vision Institute, Tijuana, Mexico.

METHODS

This retrospective noncomparative interventional case series evaluated 14 eyes of 12 patients with ICL implantations who developed a cataract and simultaneously had ICL removal and cataract extraction with IOL implantation. The follow-up time was at least 6 months (range 6 to 24 months). Visual acuity (logMAR), manifest refraction, intraocular pressure, and adverse events were recorded.

RESULTS

Of the 12 patients (14 eyes), 10 patients (12 eyes) had ICL surgery to correct high myopia and 2 patients (2 eyes), to correct hyperopia. The mean uncorrected visual acuity after ICL implantation (before cataract development), before cataract surgery, and after cataract surgery were 0.48 +/- 0.32, 0.83 +/- 0.34, and 0.40 +/- 0.27, respectively. The mean best corrected visual acuity (BCVA) before ICL implantation, after ICL implantation, and after cataract surgery were 0.31 +/- 0.21, 0.28 +/- 0.19, and 0.27 +/- 0.21, respectively. The mean final manifest spherical equivalent was 0.30 diopters (D) +/- 1.07 (SD) (range +2.38 to 2.0 D). Ten eyes (71.4%) were within +/-1.0 D of the calculated target. One eye had a tear in the posterior capsule with vitreous loss during cataract surgery. No other intraoperative, perioperative, or postoperative complications were observed. No loss of BCVA was recorded at the last postoperative visit.

CONCLUSIONS

Lens opacities and cataract formation are a potential complication of ICL surgery. The removal of the ICL and the cataract with IOL implantation was found to be safe, with predictable refractive results.

The Refractive Status and Vision Profile: Evaluation of psychometric properties and comparison of Rasch and summated Likert-scaling

The psychometric properties of the Refractive Status and Vision Profile (RSVP) questionnaire were evaluated using Rasch analysis. Ninety-one myopic patients from a refractive surgery clinic and general optometric practice completed the RSVP. Rasch analysis of the RSVP ordinal data was performed to examine for unidimensionality and item reduction. The traditional Likert-scoring system was compared with a Rasch-scored RSVP and a reduced item Rasch-scored RSVP. Rasch analysis of the original RSVP showed poor targeting of item difficulty to patient quality of life, items with a ceiling effect and underutilized response categories. Combining the underutilized response scales and removal of redundant and misfitting items improved the internal consistency and targeting of the RSVP, and the reduced 20-item Rasch scored RSVP showed greater relative precision over standard Likert scoring in discriminating between the two subject groups. A Rasch scaled quality of life questionnaire is recommended for use in refractive outcomes research.

Étude prospective de la sensibilité au contraste et des effets visuels après LASIK

PURPOSE

To evaluate changes in visual effects (contrast sensitivity, halos, and glare) following laser in situ keratomilleusis (LASIK).

PATIENTS AND METHODS

In this prospective study, 72 eyes had LASIK to correct myopia. Contrast sensitivity was tested preoperatively, as well as 6 and 12 months postoperatively. The spatial frequencies tested were 3, 6, 12, and 18 cycles per degree (c/d). There were two groups: group 1 for myopia between -6 D (n=30) and -7.5 D and group 2 for myopia between -7.5 D and -10 D (n=25). There were 17 cases with loss of sight. For each visit, pupil diameter, halos, and glare were measured.

RESULTS

Contrast sensitivity was better in group 1 than in group 2 (p<0.05) (for spatial frequencies of 3, 12, 18, c/d). In group 1, contrast sensitivity decreased 6 months postoperatively for all spatial frequencies (p<0.05); 12 months after surgery the changes were not significant. In group 2, changes were not significant. For halos and glare, pre- and postoperative percentages were not different. There was no correlation with pupil diameter.

CONCLUSIONS

After LASIK to correct myopia, there may be a persistent decrease in contrast sensitivity. Changes are only significant at 6 months postoperatively. Patients should be informed preoperatively of this possible decrease in functional vision.