Accommodative changes after photorefractive keratectomy in myopic eyes

Evaluation of Early Accommodation Outcomes Following Femtosecond Laser-Assisted in situ Keratomileusis and Small Incision Lenticule Extraction

PURPOSE

The aim of this study is to assess the changes and differences in early postoperative binocular accommodative function following femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE).

METHODS

In this retrospective study, 120 patients (240 eyes) diagnosed with low-to-moderate and high myopia, who underwent either FS-LASIK or SMILE procedures were included. The assessment encompassed measurements of accommodative facility, accommodation time, relaxation time, and accommodation-to-relaxation ratio using a smart flipper. Measurements were taken preoperatively, as well as at 1 day, 1 week, and 1 month postoperatively. Additionally, the visual fatigue scale score was assessed and compared at the 1 month mark post-surgery. Changes in parameters were quantified by calculating the difference between preoperative values and those recorded at each postoperative time point.

RESULTS

At 1 month post-surgery, both FS-LASIK and SMILE procedures demonstrated potential for recovery or even improvement in accommodative facility, accommodation time, relaxation time, and accommodation-to-relaxation ratio compared to preoperative levels. The FS-LASIK group exhibited a greater magnitude of change in accommodative facility postoperatively compared to the SMILE group. In the low-to-moderate myopia subgroup, the FS-LASIK group exhibited lower changes in accommodation time and visual fatigue scale score at 1 month post-surgery compared to the SMILE group, with all associated p-values <0.05.

CONCLUSIONS

Early postoperative recovery of accommodation function was slower following SMILE compared to FS-LASIK. Additionally, the severity of visual fatigue at 1 month post-surgery was greater in the SMILE group than in the FS-LASIK group. This difference in visual fatigue levels may be attributed to the delayed recovery observed in postoperative SMILE procedures.

The changes and causes of asthenopia after ICL implantation

OBJECTIVE

To detect the presence of asthenopia after implantation of Implantable Collamer Lens (ICL).

METHOD

Design: prospective observational case series. Patients with myopia and/or astigmatism who underwent ICL surgeries and completed 3-month follow-up were enrolled. Asthenopia scores, amplitude of accommodation (AA), positive/negative relative accommodation (PRA/NRA), accommodative facility (AF), the ratio of accommodative convergence and accommodation (AC/A), Schirmer test, noninvasive breakup time (NBUT), and HOA were examined before surgeries and at 1 week, 1 month and 3 months postoperatively then statistically analyzed.

RESULTS

Symptoms of asthenopia were significantly decreased at 1 week after ICL surgeries than those before surgeries, but increased gradually as time went by, eventually recovered at 3 months postoperatively. AA, AF, AC/A decreased 1 week postoperatively, returned to the baseline at 1 month and were improved at 3 months after surgeries. NBUT at 1 week, 1 month and 3 months after surgeries were significantly decreased and was the lowest at 1 week postoperatively. PRA, NRA, Schiermer values and HOA had no significant change. Correlation analysis showed that the lower AF and NBUT after ICL surgeries, the more severe the asthenopia symptoms.

CONCLUSION

The symptoms of asthenopia aggravated transiently after ICL implantation surgeries, but improved gradually with time. AF and NBUT were important factors affecting the changes of asthenopia.

Changes in accommodation and convergence function after refractive surgery in myopic patients

In recent years, with the gradual maturation of myopia correction surgery, the changes in binocular visual function after surgery have attracted widespread attention. The accommodation of facility, the amplitude of accommodation, relative accommodation, and accommodation convergence/accommodation assembly are essential parameters for assessing binocular visual function. The changes in these parameters are significant for guiding patients in the design of the preoperative surgical approach and alleviating postoperative visual fatigue. This paper aims to guide the preoperative assessment, design, and postoperative visual training of refractive surgery in myopic patients from the perspective of changes in binocular visual function before and after myopia and surgery, which can improve accommodation and convergence function in patients after refractive surgery.

Comparison of accommodation and accommodative micro-fluctuation after implantable collamer lens and LASIK surgery for myopia

BACKGROUND

To longitudinally analyze and compare the accommodative micro-fluctuation (MFs) and accommodative function between myopic patients after implantable collamer lens (ICL) implantation and laser in situ keratomileusis (LASIK).

METHODS

Patients with good corrected visual acuity (20/20 or better) and underwent ICL (V4c) and LASIK for myopic-correction (ranging from - 3.50 to - 8.50 D) were recruited. Refraction, amplitude of accommodation (AMP), accommodative lag, higher-order aberration (HOA), and MFs were recorded before surgery and 1 and 3 months after surgery. The ACOMEREF automatic refractor was used to measure the high-frequency component (HFC) of the MFs, which suggested tension of the ciliary muscle.

RESULTS

The study comprised 120 eyes. At 3 months after surgery, the manifest refractive spherical equivalent of the ICL and LASIK groups were - 0.11 and - 0.09 D, respectively (p = 0.46). HFC values were significantly higher at 1 month (p = 0.03) and 3 months postoperatively (p = 0.03) in the ICL group compared to that in the LASIK group. The ocular HOA of the ICL group was 1.08 ± 0.43 μm, which was lower than the LASIK group 1.45 ± 0.54 μm (p = 0.01). No significant differences in AMP and accommodative lag between groups were noted at 3 months postoperatively. There was a positive correlation between HFC and vault of the ICL lens (r² = 0.14, p = 0.005). There were no correlations between HFC and ocular HOA and postoperative MRSE in the two groups (all p>0.05).

CONCLUSIONS

The HFC increased significantly after an early period of ICL implantation compared to laser in situ keratomileusis for myopic correction, which indicated increased tension of the ciliary muscle, and had a positive correlation on the vault of the ICL lens; However, studies with longer follow-up time and more structural evaluation are needed.

'The role of accommodative function in myopic development: A review.'

Purpose: Involvement of the accommodative mechanism in myopia progression has been hypothesised and investigated over the past years, given the emerging myopia crisis across the globe. This review aimed at exploring the clinical role of accommodative function in myopia development.Methods: A literature search of MEDLINE and EMBASE was performed from conception to May 2021.Results:The initial stimulus for accommodation is derived from near work, in an attempt of the eye to obtain a clear image. When there is a lag in the accommodative response, the resulting blurred retinal image is believed to precipitate axial elongation and lead to myopia development. The dynamic accommodative functions implicated in binocular vision evaluation include the accommodative accuracy, amplitude and facility. Association of these accommodative parameters to current treatment options for myopia control is of great clinical interest. Effective myopia treatments, including orthokeratology, multifocal lenses and atropine eyedrops appear to induce changes in the dynamic accommodative response.Conclusions: Current knowledge indicates an evident relationship between the accommodative mechanism and myopia development. Further investigation by future studies is warranted in order to explore the use of accommodative function as a promising myopia-monitoring tool.

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

BACKGROUND

To compare the correction effect and optical quality after small-incision lenticule extraction (SMILE) and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia.

METHODS

51 high myopia eyes after SMILE and 49 high myopia eyes after FS-LASIK were enrolled and divided into two groups retrospectively. The OQAS and iTrace analyzer were used for optical quality inspection. Between the two groups the spherical equivalent (SE), astigmatism, uncorrected distant visual acuity (UDVA), strehl ratio (SR), modulation transfer function cutoff frequency (MTF cutoff), objective scatter index (OSI) and wavefront aberrations were analyzed and compared before surgery and at 1, 6 and 12 months after surgery.

RESULTS

After the operation: (1) SE and astigmatism declined and UDVA increased significantly in both groups, and UDVA was better after SMILE than FS-LASIK. (2) SR and MTF cutoff reduced and OSI increased significantly after SMILE and FS-LASIK. SR and MTF cutoff were significantly higher after SMILE than FS-LASIK. OSI was significantly lower after SMILE than FS-LASIK. (3) The total wavefront aberration, total low-order wavefront aberration, defocus and astigmatism aberration as well as trefoil aberration reduced significantly in both groups. The total high-order wavefront aberration increased significantly after FS-LASIK. The spherical and coma aberration increased significantly in both groups. The total high-order wavefront aberration and coma aberration at 1 month were higher after FS-LASIK than SMILE.

CONCLUSION

The optical quality descended after SMILE and FS-LASIK. SMILE was superior to FS-LASIK at the correction effect and optical quality for high myopia. The combination of OQAS and iTrace analyzer is a valuable complementary measurement in evaluating the optical quality after the refractive surgery.

TRIAL REGISTRATION

This is a retrospective study. This research was approved by the ethics committee of Xiangya Hospital and the IRB approval number is 201612074.

Transepithelial photorefractive keratectomy for myopia: effect of age and keratometric values

AIM

To investigate demographic and preoperative factors increasing the risk of ametropia following transepithelial photorefractive keratectomy (transPRK) in myopia and myopic astigmatism.

METHODS

This retrospective cohort study included myopic eyes (-0.50 to -8.75 D) with or without astigmatism (up to 3.50 D) enrolled at Dr. Yap Eye Hospital Yogyakarta. TransPRK was performed using Technolaz 217z100 excimer laser. Subjects were clustered into ametropia and emmetropia group based on uncorrected distance visual acuities (UDVA) 3mo post-operatively. Multiple preoperative and intraoperative parameters were analyzed using Logistic regression to obtain their effect on ametropia risk following transPRK.

RESULTS

A total of 140 eyes of 87 consecutive subjects were studied. Prevalence of ametropia following transPRK was 20 (14.29%) eyes. Subjects in ametropia group were significantly older than the emmetropia group (31.80±14.23 vs 18.88±2.41, respectively; P<0.001). Bivariate Logistic regression analysis showed that older age (OR=1.23), higher preoperative spherical equivalent (>-6 D; OR=12.78), steeper anterior keratometric readings (Kmax>45 D and mean K>44 D; OR=4.28 and 4.35, respectively) increased the risk of ametropia following transPRK. Adjusted multivariate Logistic regression analysis showed that age was the strongest predictor for the incidence of ametropia following transPRK. Complications of transPRK were overcorrection, suspected posterior keratoectasia and accommodation insuffiency.

CONCLUSION

Older age can be the strongest factor for increasing ametropia risk following transPRK. Cut-off points of Kmax and mean K at 45 and 44 D respectively are proposed as the predictors for ametropia following transPRK.

Changes in accommodative function following small-incision lenticule extraction for high myopia

PURPOSE

To examine whether the amplitude of accommodation, the accommodative response, and the accommodative facility is affected and correlated with changes in higher-order aberrations for patients with high myopia surgically treated with small-incision lenticule extraction (SMILE).

METHODS

35 highly myopic eyes (myopic spherical equivalent of at least 6 diopters) of 35 patients treated with SMILE were included. Assessments were made before and 3 months after surgery. Donders push-up-method was used to measure the amplitude of accommodation. The accommodative response was assessed using an open-field autorefractor"Grand Seiko WAM-5500" (Grand Seiko Co. Ltd., Hiroshima, Japan) in combination with a Badal optometer and stimuli of accommodation at 0.0, 0.5, 1.25, 2.0, 3.0, and 4.0 D, respectively. Accommodative facility was measured at 40 cm with ±2,00D flipper lenses. All measurements of accommodation were performed monocularly with the refractive error corrected with soft contact lenses.

RESULTS

The amplitude of accommodation did not change statistically significantly (mean difference -0.24 D (SD 0.98), 95% CI of mean difference -0.58 D to 0.11 D, paired-sample t(34) = -1.39; P = 0.17). The accommodative responses at 0.0, 0.5, 1.25, 2.0, 3.0, and 4.0 D did not statistically significantly change either (F(6,29) = 1.15; P = .36). Finally, the accommodative facility was also unchanged with a mean difference of 1.11 cycles per minute (SD 5.11, 95% CI of mean difference -0.64 to 2.87, paired-sample t(34) = 1.29; P = 0.21). No clinically significant associations between changes in accommodation and higher-order aberrations were found.

CONCLUSIONS

SMILE does not alter the amplitude of accommodation, the accommodative response, nor the accommodative facility for highly myopic patients, and the surgically induced corneal higher-order aberrations do not affect the accommodative function.

Accommodation changes after visian implantable collamer lens with central hole for high myopia: A STROBE-compliant article

To characterize the accommodative changes in high-myopic patients after the implantation of the Visian implantable collamer lens with a central hole (ICL V4c).This prospective study enrolled 30 patients (60 eyes) with uneventful surgery of ICL V4c implantation. Parameters including amplitude of accommodation (AA), monocular and binocular facility of accommodation (FA), positive relative accommodation (PRA), negative relative accommodation (NRA), near point convergence (NPC), accommodative response, and accommodation convergence/accommodation (AC/A) ratio were assessed before surgery, at 1 and 3 months postoperatively.Mean preoperative SE was -10.86 ± 3.87 diopter (D) (range, -6.5D to -22D), which improved to 0.27 ± 0.51D at 1 month and 0.09 ± 0.47D at 3 months after surgery (P <.001). Significant improvements in AA, NRA, PRA, NPC, monocular, and binocular FA were seen at 1 month and 3 months postoperatively compared to the values before surgery (P <.05), but the difference between 1 month and 3 months were not obvious (P >.05) except for binocular FA (P = .002). However, no significant changes were seen in either AC/A ratio or accommodative response at any postoperative follow-ups in contrast to those before surgery (P >.05). Similar changes in accommodative function were found in patients with less myopia (> -10.00D) and those with more myopia (≤10.00D) (P >.05).The accommodative function of eyes after the implantation of ICL V4c is enhanced and stabilizes at 1 month, except for the AC/A ratio and accommodative response. The clearer vision and increased amount of accommodation for near target account for the majority of the improvement.

Binocular vision alterations after refractive and cataract surgery: a review

To review binocular and accommodative disorders documented after corneal or intraocular refractive surgery, in normal healthy prepresbyopic patients. A bibliographic revision was performed; it included works published before 1st July 2017 where accommodation and/or binocularity was assessed following any type of refractive surgical procedure. The search in Pubmed yielded 1273 papers, 95 of which fulfilled the inclusion criteria. Few publications reporting binocular vision and/or accommodative changes after refractive surgery in normal subjects were found. The reduction in fusional vergence is the most frequently reported alteration. Anisometropia is an important risk factor for postoperative binocular vision-related complaints. Most diplopia-related visual complaints, irrespective of the surgical procedure, were in fact misdiagnosed preoperative disorders. The preoperative evaluation of patients seeking spectacle/contact lens independence should include a complete binocular and accommodation assessment where parameters such as the phoric posture, accommodative amplitude and facility, near point of convergence, fusional reserves and accommodative convergence/accommodation coefficient are measured. This would allow the identification of risk factors that could compromise the success of the refractive surgery and cause clinical symptoms.

A Comparison of the Effects of Orthokeratology Lens, Medcall Lens, and Ordinary Frame Glasses on the Accommodative Response in Myopic Children

OBJECTIVE

To observe and compare changes in accommodative response between myopic children wearing ordinary frame glasses (OFG), Mouldway orthokeratology lenses (M-OK), and medcall lenses (ML).

METHODS

A total of 240 myopic children were divided into three groups: OFG [n=90]; M-OK [n=90]; and ML [n=60]). The diopter, accommodative lag, and binocular accommodative facility before wearing glasses (T0) and 1-year after wearing glasses (T1) were compared among the three groups.

RESULTS

Commercially available software was used to perform statistical analysis, and the data were expressed as mean±SD. There were no significant differences among the three groups at T0. The accommodative lags in M-OK and ML at T1 were significantly lower than those at T0; this finding was most evident in M-OK. Although accommodative facility increased in all three groups, the increase was most evident in M-OK and ML.

CONCLUSION

Mouldway orthokeratology lenses and ML can reduce the accommodative lag and increase the accommodative facility in myopic children. Compared with ML, M-OK showed considerably more marked effects to myopia progression in children.

Accommodative changes after SMILE for moderate to high myopia correction

Background

To investigate accommodative response and accommodative lag changes after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction.

Methods

A total of 32 eyes of 32 patients with no strabismus who underwent SMILE were enrolled in this prospective clinical study. The accommodative response was obtained viewing monocularly with spherical equivalent refractive error corrected, using an open-field autorefractor at different stimulus levels (2.00D, 2.50D, 3.00D, 4.00D and 5.00D) for the right eye before a standard SMILE surgery and at 1-month follow-up after surgery.

Results

The mean age of the patients were 23.34 ± 2.90 years and the mean preoperative manifest refraction spherical equivalent was −5.74 ± 1.98 diopters. Significant differences were detected in both preoperative and postoperative accommodative responses to different stimulus levels (P < 0.001). Multiple linear regression model analysis revealed preoperative manifest refractive spherical equivalent (P = 0.006) and preoperative accommodative lag (P = 0.04) showed a significant impact on postoperative accommodative lag.

Conclusions

This is the first report of accommodative changes after SMILE. Our preliminary results showed that a decrease in postoperative accommodative lag that might be related to the relief of the visual discomfort symptom.

Morphology, topography, and optics of the orthokeratology cornea

The goal of this work was to objectively characterize the external morphology, topography, and optics of the cornea after orthokeratology (ortho-k). A number of 24 patients between the ages of 17 and 30 years (median=24  years) were fitted with Corneal Refractive Therapy® contact lenses to correct myopia between −2.00 and −5.00 diopters (D) (median=−3.41  D). A classification algorithm was applied to conduct an automatic segmentation based on the mean local curvature. As a result, three zones (optical zone, transition zone, and peripheral zone) were delimited. Topographical analysis was provided through global and zonal fit to a general ellipsoid. Ray trace on partially customized eye models provided wave aberrations and retinal image quality. Monozone topographic description of the ortho-k cornea loses accuracy when compared with zonal description. Primary (C40) and secondary (C60) spherical aberration (SA) coefficients for a 5-mm pupil increased 3.68 and 19 times, respectively, after the treatments. The OZ area showed a strong correlation with C40 (r=−0.49, p<0.05) and a very strong correlation with C60 (r=0.78, p<0.01). The OZ, as well as the TZ, areas did not correlate with baseline refraction. The increase in the eye’s positive SA after ortho-k is the major factor responsible for the decreased retinal optical quality of the unaccommodated eye.

Transepithelial photorefractive keratectomy mode using SCHWIND-ESIRIS excimer laser: initial clinical results

AIM

To evaluate postoperative pain, uncorrected visual acuity (UCVA), and cornea haze value after transepithelial photorefractive keratectomy (T-PRK) performed with aspherical ablation profile using SCHWIND ESIRIS excimer laser.

METHODS

Retrospective case series. Fifty-nice eyes (32 patients) with myopia associated with or without astigmatism underwent phototherapeutic keratectomy (PTK) followed by photorefractive keratectomy (PRK) which performed by Optimized Refractive Keratecomy (ORK)-CAM software based on aspherical ablation profile using SCHWIND ESIRIS excimer laser. Postoperative pain scale was measured on a questionnaire through five levels. Haze was graded by five grades, and UCVA, manifest refraction spherical equivalent (MRSE) were analyzed.

RESULTS

Mean pain level was (1.37±0.613) (range: 1 to 3), the mean time picking out the soft contact lens was (6.22±1.73) days, at 3 months, UCVA was 1.0 for 40 eyes (67.8%), 0.5 for all eyes (100.0%). The UCVA was significantly less than the preoperative best spectacle corrected visual acuity (BSCVA) (t=-2.84, P=0.006), haze value was (0.27±0.25), no patients had a haze grade up to 2. Mean MRSE was (0.76±0.96) diopter(D) by 3 months.

CONCLUSION

The outcomes from this study show that using the SCHWIND ESIRIS aspherical ablation profile for transepithelial PRK has a good visual result. The primary advantage is related to a spherical ablation profile, automatically considers the ablation volume of the stroma and the accurate and smooth removal of the epithelium with PTK. Additional studies are needed to determine long-term outcomes.