One year follow-up of contrast sensitivity following conventional laser in situ keratomileusis and laser epithelial keratomileusis

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.

Comparison of contrast sensitivity based on the surgical results for intermittent exotropia

AIM

To compare contrast sensitivity (CS) based on the surgical results for intermittent exotropia (IXT) and to examine the relationship between CS and photophobia.

METHODS

Medical records of the patients who underwent bilateral lateral rectus muscle recession for IXT between 4 and 12 years old were reviewed retrospectively. They were categorized based on the surgical results; successful correction group (n=36) and overcorrection group (esotropia ≥10 PD at 3mo postoperatively, n=18). Using CGT-2000 test for CS was performed binocularly, and subjective reports of photophobia was investigated preoperatively and at 3mo postoperatively. Objective photophobia was defined as a significant decrease in CS in the presence of glare.

RESULTS

Preoperatively, there was no difference in CS between the groups. Postoperatively, under mesopic conditions, significant improvement of CS was observed at 6.3°, 4°, and 2.5° in the successful correction group and at 6.3° and 4° in the overcorrection group, regardless of glare. Under photopic conditions, at all visual angles except 0.64°, improvement in CS was noted in both groups while CS worsened significantly at 0.64° in the overcorrection group postoperatively. At all visual angles under photopic conditions postoperatively, regardless of glare, CS in the overcorrected group was significantly worse than that in the successful correction group, and CS was significantly decreased by addition of glare in both groups. All patients except one (96.4%) in the successful correction group and 8 patients (61.5%) in overcorrection group showed improvement of photophobia postoperatively, which correlated with CS under photopic conditions (P=0.001, 0.03).

CONCLUSION

After surgery for IXT, CS under photopic conditions improve at all visual angles except 0.64°, while CS is significantly worse in the overcorrection group postoperatively at 0.64°. Subjective photophobia have significant correlation with CS under photopic conditions, and may be used as an objective indicator of photophobia.

Comparison of postoperative visual quality after SMILE and LASEK for high myopia: A 1-year outcome

PURPOSE

To compare the 1-year outcome of visual quality after laser-assisted subepithelial keratomileusis (LASEK) and femtosecond laser-assisted small incision lenticule extraction (SMILE) for high myopia correction.

MATERIALS AND METHODS

This prospective, comparative study included 24 eyes of 24 patients in the LASEK group, with a mean spherical equivalent (SE) of -7.59 ± 1.32 diopters, and 26 eyes of 26 patients in the SMILE group, with a mean SE of -7.91 ± 1.08 diopters. Visual acuity, corneal topography, contrast sensitivity (CS), and wavefront aberrations were recorded preoperatively and compared with postoperative measurements. Objective scatter index (OSI) and modulation transfer function (MTF) cut-off frequency were measured 1 year postoperatively.

RESULTS

One year postoperatively, the two groups demonstrated no significant difference in the CS at all spatial frequencies. The increments of higher-order aberrations (HOAs) (HOA = 0.583 ± 0.210 μm), including spherical aberration (SA) (SA = 0.546 ± 0.249 μm), were higher (P < 0.05) in the LASEK group than those in the SMILE group (HOA = 0.451 ± 0.143 μm; SA = 0.450 ± 0.340 μm) after surgery. There were no significant differences in the increments of coma and trefoil aberrations between the two groups. The OSI and MTF cut-off frequency exhibited no significant differences between the two groups postoperatively. No vision-threatening complications were noted at any stage in either group.

CONCLUSIONS

Both LASEK and SMILE are safe and effective surgical options for the correction of high myopia. SMILE has a lower HOAs and SA induction rate 1 year postoperatively.

Prospective Cohort Comparison of Visual Acuity and Contrast Sensitivity Between Femto Laser In Situ Keratomileusis and Orthokeratology for Low-to-Moderate Myopia

PURPOSE

To compare the visual acuity and contrast sensitivity (CS) after femto laser in situ keratomileusis (fLASIK) and orthokeratology (OK) in patients with low-to-moderate myopia.

METHODS

A total of 68 patients were enrolled in this prospective cohort study. Of these, 40 eyes from 40 patients with low-to-moderate myopia underwent fLASIK and 28 eyes from 28 patients underwent OK. In addition to uncorrected distance visual acuity and corrected distance visual acuity, photopic and mesopic CS (with CSV-1000E) were tested before treatment and at 1, 3, and 6 months after treatment.

RESULTS

The preoperative refraction and CS were not significantly different between the groups (P>0.05). Postoperative visual acuity and refraction were similar (P>0.05). The photopic CS of the fLASIK group was better than that of the OK group (P<0.01). The fLASIK mesopic CS was better than the OK at 3 c/d (P=0.023). In the fLASIK group, only the photopic CS of postoperative 12 c/d decreased at 1 month and 3 months (P<0.01) and 18 c/d decreased at 1 month (P=0.002); whereas in the OK group, all the postoperative photopic CS values decreased at 1 month (all P<0.01) and 3 months (P<0.05) and increased to the normal level at 6 months (P>0.05). While as to the mesopic CS, in the fLASIK group, the 3 c/d, 6 c/d, and 18 c/d decreased at 1 month (P<0.05) and in the OK group, the 3 c/d decreased at 1 month and 3 months (P<0.05) and the 6 c/d decreased at 3 months (P=0.041), and the 12 c/d and 18 c/d decreased at 1 month (P<0.01).

CONCLUSIONS

These results show that fLASIK provides better visual quality than OK for patients with low-to-moderate myopia.

Comparison of Visual Quality After SMILE and LASEK for Mild to Moderate Myopia

PURPOSE

To compare the objective and subjective quality of vision after femtosecond laser-assisted small incision lenticule extraction (SMILE) and laser-assisted subepithelial keratomileusis (LASEK) for mild to moderate myopia.

METHODS

This prospective, comparative study included 65 eyes of 33 patients in the SMILE group, with a mean spherical equivalent (SE) of -4.16 ± 0.82 diopters, and 50 eyes of 25 patients in the LASEK group, with a mean SE of -3.81 ± 0.97 diopters. Visual acuity, corneal topography, contrast sensitivity, and wavefront aberrations were recorded preoperatively and compared with postoperative measurements. A quality of vision questionnaire was scored and analyzed 3 months postoperatively.

RESULTS

Three months postoperatively, the SMILE group had fewer (P < .05) higher-order aberrations (HOAs) (0.390 ± 0.175 µm), including spherical aberration (SA) (0.262 ± 0.242 µm), than the LASEK group (HOAs = 0.479 ± 0.148 µm, SA = 0.576 ± 0.287 µm, trefoil = 0.465 ± 0.248 µm). There was no significant difference in the amount of coma and trefoil between the two groups after surgery. Analysis of the scores of glare and halos in the quality of vision questionnaire revealed that SMILE (night glare = 1.25 ± 1.22, halos = 0.97 ± 1.12) provided a better quality of vision (P < .05) than LASEK (night glare = 2.32 ± 1.99, halos = 1.96 ± 1.77). The two groups demonstrated no significant difference in contrast sensitivity 3 months postoperatively. No vision-threatening complications were noted at any stage in either group.

CONCLUSIONS

Both SMILE and LASEK are safe and effective surgical procedures in the correction of myopia. SMILE has a lower induction rate of HOAs and a higher degree of patient satisfaction than LASEK at 3 months postoperatively.

Contrast Sensitivity after Pars Plana Vitrectomy: Comparison between Macula-On and Macula-Off Rhegmatogenous Retinal Detachment

PURPOSE

To evaluate the contrast sensitivity (CS) of eyes successfully repaired by vitrectomy for rhegmatogenous retinal detachment (RRD) with or without preoperative macular involvement.

METHODS

In this retrospective, consecutive, interventional case series, 109 eyes received primary vitrectomy for RRD, of which 36 with at least 12 months of follow-up and a best-corrected visual acuity (BCVA) ≥1 at 12 months postoperatively were investigated. The main outcome measurements were BCVA and CS at 12 months postoperatively. Patients with macula-on RRD preoperatively were included in the macula-on group, and patients with macula-off RRD preoperatively were included in the macula-off group. The between-group difference in CS under evening vision conditions was measured with a Takagi glare tester CGT-2000 at 6 visual angles and 13 contrast levels with and without glare.

RESULTS

CS was significantly lower in the macula-off group for targets with visual angles of 1.6, 1.0, and 0.64° with glare (p < 0.05) and for the target with a visual angle of 0.64° without glare (p < 0.05).

CONCLUSIONS

CS in the higher spatial frequency range (especially with glare) is reduced in macula-off RRD patients with good postoperative BCVA compared to macula-on RRD patients with good postoperative BCVA.

Visual performance after conventional LASIK and wavefront-guided LASIK with iris-registration: results at 1 year

AIM

To compare visual performance of wavefront-guided laser in situ keratomileusis (LASIK) with iris-registration (Wg-LASIK group) and conventional LASIK (LASIK group) one year after surgery and analyze the correlation between wavefront aberrations and visual performance.

METHODS

Eight hundred and fifty-two myopic eyes of 430 patients were enrolled in this prospective study and divided into two groups: Wg-LASIK group (436 eyes) and LASIK group (416 eyes). A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square (RMS) of higher order aberrations, and Optec 6500 visual function instrument was used to measure contrast sensitivity (CS) before and 3, 6, 12 months after surgery.

RESULTS

The mean spherical equivalent (SE) in Wg-LASIK group was significantly better than those in LASIK group one year after surgery (P=0.024). Wg-LASIK eyes showed better CS values than LASIK eyes at all spatial frequencies with and without glare after surgery (P all<0.01). Moreover, the increase of higher RMS (RMSh), coma, RMS3, RMS4, RMS5 in Wg-LASIK group were significantly lower than those in LASIK group 1 year after surgery (P all<0.05). The increase of coma, spherical aberration (SA), RMS3 and RMS4 in Wg-LASIK and coma and RMS3 in LASIK group were negatively correlated with reduction of contrast sensitivity 1 year after surgery.

CONCLUSION

A significant better visual performance is got in Wg-LASIK group compared with LASIK group 1 year after surgery, and the Wg-LASIK is particularly suitable for eyes with high-magnitude RMSh.

Wavefront-optimized excimer laser in situ keratomileusis for myopia and myopic astigmatism: refractive outcomes and corneal densitometry

PURPOSE

To determine the refractive outcomes of wavefront-optimized laser in situ keratomileusis (LASIK) treatments, in particular to measure corneal densitometry after LASIK using the densitometry function of the Pentacam Scheimpflug system.

SETTING

Division of Ophthalmology and Visual Sciences, University of Nottingham, United Kingdom.

DESIGN

Cohort study.

METHODS

Changes in postoperative visual acuity, refraction, and contrast sensitivity were evaluated after wavefront-optimized laser treatment. Corneal densitometry was evaluated with the Scheimpflug system before and after LASIK.

RESULTS

One year postoperatively, the uncorrected distance visual acuity was 6/6 or better in 92% of eyes and 6/9 or better in all eyes. Eighty-six percent of eyes had no change in the corrected distance visual acuity (CDVA); 4% gained 1 or more lines. Wavefront-optimized LASIK was stable over 1 year postoperatively. Eighty-nine percent of eyes were within ±0.50 diopter (D) and 100% were within ±1.00 D of the intended correction 1 year postoperatively. Contrast sensitivity showed a nonsignificant improvement (1.55 ± 0.10 [SD] preoperatively to 1.57 ± 0.09 12 months postoperatively) (P > .05). There was a nonsignificant increase in corneal densitometry 1 year postoperatively (from 12.72 ± 2.43 to 13.04 ± 2.58) (P > .05). No correlation was found between corneal densitometry and contrast sensitivity or CDVA.

CONCLUSIONS

Wavefront-optimized LASIK gave excellent refractive and visual outcomes and did not seem to affect corneal densitometry significantly 1 year postoperatively. However, larger studies may show a masked effect on corneal densitometry.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.