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BMC Ophthalmology Apr 2024The purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term...
BACKGROUND
The purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term myopic regression.
METHODS
We included civilian pilots who had undergone CRS to correct their myopia and who had at least 5 years of follow-up. We collected retrospective data and completed eye examinations and a questionnaire to assess their eye habits.
RESULTS
A total of 236 eyes were evaluated in this study. 211 eyes had Intrastromal ablations (167 eyes had laser in situ keratomileusis, LASIK, 44 eyes had small incision lenticule extraction, SMILE) and 25 eyes had subepithelial ablations (15 eyes had laser epithelial keratomileusis, LASEK and 10 eyes had photorefractive keratectomy, PRK). The mean preoperative spherical equivalent (SE) was - 2.92 ± 1.11 D (range from - 1.00 to -5.00 D). A total of 56 eyes (23.6%) suffered from myopic regression after CRS. Comparisons of individual and eye characteristics between the regression and non-regression groups revealed statistically significant differences in age, cumulative flight time, postoperative SE (at 6 months and current), uncorrected visual acuity (UCVA), accommodative amplitude (AA), positive relative accommodation (PRA), postoperative period, types of CRS and eye habits. Generalized propensity score weighting (GPSW) was used to balance the distribution of covariates among different age levels, types of CRS, cumulative flying time, postoperative period and continuous near-work time. The results of GPS weighted logistic regression demonstrated that the associations between age and myopic regression, types of CRS and myopic regression, continuous near-work time and myopic regression were significant. Cumulative flying time and myopic regression, postoperative period and myopic regression were no significant. Specifically, the odds ratio (OR) for age was 1.151 (P = 0.022), and the OR for type of CRS was 2.769 (P < 0.001). The OR for continuous near-work time was 0.635 with a P value of 0.038.
CONCLUSIONS
This is the first report to analyze myopic regression after CRS in civilian pilots. Our study found that for each year increase in age, the risk of civilian pilots experiencing myopic regression was increased. Intrastromal ablations had a lower risk of long-term myopia regression than subepithelial ablations. There is a higher risk of myopic progression with continuous near-work time > 45 min and poor accommodative function may be related factors in this specific population.
Topics: Humans; Infant; Retrospective Studies; Cornea; Photorefractive Keratectomy; Visual Acuity; Refraction, Ocular; Keratomileusis, Laser In Situ; Lasers, Excimer; Myopia; Treatment Outcome
PubMed: 38561680
DOI: 10.1186/s12886-024-03399-5 -
Frontiers in Bioengineering and... 2024To evaluate the change in corneal biomechanics in patients with postoperative ectasia risk when combining two common laser vision correction procedures (tPRK and...
To evaluate the change in corneal biomechanics in patients with postoperative ectasia risk when combining two common laser vision correction procedures (tPRK and FS-LASIK) with cross-linking (in tPRK Xtra and FS-LASIK Xtra). The study included 143 eyes of 143 myopic, astigmatic patients that were divided into non-cross-linked refractive surgery groups (non-Xtra groups, tPRK and FS-LASIK) and cross-linked groups (Xtra groups, tPRK Xtra and FS-LASIK Xtra) according to an ectasia risk scoring system. The eyes were subjected to measurements including the stress-strain index (SSI), the stiffness parameter at first applanation (SP-A1), the integrated inverse radius (IIR), the deformation amplitude at apex (DA), and the ratio of deformation amplitude between apex and 2 mm from apex (DARatio2mm). The measurements were taken preoperatively and at 1, 3, and 6 months postoperatively (pos1m, pos3m, and pos6m). Posterior demarcation line depth from the endothelium (PDLD) and from the ablation surface (DLA) were recorded at pos1m. SP-A1 significantly decreased, while IIR, deformation amplitude, and DARatio2mm increased significantly postoperatively in all four groups ( < 0.01)-all denoting stiffness decreases. In the FS-LASIK group, the changes in IIR, DA, and DARatio2mm were 32.7 ± 15.1%, 12.9 ± 7.1%, and 27.2 ± 12.0% respectively, which were significantly higher ( < 0.05) compared to 20.1 ± 12.8%, 6.4 ± 8.2%, and 19.7 ± 10.4% in the FS-LASIK Xtra group. In the tPRK group, the change in IIR was 27.3 ± 15.5%, significantly larger than 16.9 ± 13.4% in the tPRK Xtra group. The changes of SSI were minimal in the tPRK (-1.5 ± 21.7%, = 1.000), tPRK Xtra (8.4 ± 17.9%, = 0.053), and FS-LASIK Xtra (5.6 ± 12.7%, = 0.634) groups, but was significant in the FS-LASIK group (-12.1 ± 7.9%, < 0.01). After correcting for baseline biomechanical metrics, preoperative bIOP and the change in central corneal thickness (△CCT) from pre to pos6m, the changes in the IIR in both FS-LASIK and tPRK groups, as well as DA, DARatio2mm and SSI in the FS-LASIK group remained statistically greater than their corresponding Xtra groups (all < 0.05). Most importantly, after correcting for these covariates, the changes in DARatio2mm in the FS-LASIK Xtra became statistically smaller than in the tPRK Xtra ( = 0.017). The statistical analysis results indicate that tPRK Xtra and FS-LASIK Xtra effectively reduced the biomechanical losses caused by refractive surgery (tPRK and FS-LASIK). The decrease in corneal overall stiffness was greater in FS-LASIK than in tPRK, and the biomechanical enhancement of CXL was also higher following LASIK than after tPRK.
PubMed: 38558790
DOI: 10.3389/fbioe.2024.1323612 -
Graefe's Archive For Clinical and... Apr 2024The goal of this study is to describe characteristics of cataract surgery patients who previously underwent laser in situ keratomileusis/photorefractive keratectomy...
PURPOSE
The goal of this study is to describe characteristics of cataract surgery patients who previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK) in comparison to non-LASIK/PRK cataract surgery patients including psychiatric comorbidities, as well as describe refractive prediction error after cataract surgery while accounting for axial length (AL) using the Barrett True-K and Barrett Universal II formulas.
METHODS
This was a retrospective study of patients from the University of Colorado Cataract Outcomes Registry. The primary outcomes were refraction prediction error (RPE), mean absolute RPE, and median absolute RPE. Outcomes were stratified by five axial length groups. Univariate and multivariate models for RPE were stratified by the AL group.
RESULTS
Two hundred eighty-one eyes with prior LASIK/PRK and 3101 eyes without are included in the study. Patients with prior LASIK/PRK were significantly younger: 67.0 vs 69.9 years, p < 0.0001. The LASIK/PRK group had significantly better mean pre-operative BCVA in comparison to the non-LASIK group, logMAR 0.204 vs logMAR 0.288, p = 0.003. The LASIK/PRK group had significantly lower rates of cardiovascular disease (18.5% vs 29.3%, p < 0.001), hypertension (49.1% vs 59.3%, p < 0.012), and type 2 diabetes (10.7% vs 26.0%, p < 0.001), and no significant difference in psychiatric disease. The absolute RPE was higher for the LASIK group for all ALs, but only significantly higher for eyes with AL less than 25 mm.
CONCLUSION
Patient eyes with prior LASIK/PRK surgery undergoing cataract surgery were significantly younger, had significantly less comorbidities, and a significantly better pre-operative BCVA. Using the Barrett formulas, absolute prediction error for eyes with longer ALs was not significantly worse for LASIK/PRK eyes than those without and the difference was smaller for eyes with longer AL.
PubMed: 38558260
DOI: 10.1007/s00417-024-06456-3 -
Journal of Clinical Medicine Mar 2024The aim of this review was to investigate the influence of various laser refractive surgery methods on the corneal endothelium in myopic patients. The role of the... (Review)
Review
The aim of this review was to investigate the influence of various laser refractive surgery methods on the corneal endothelium in myopic patients. The role of the corneal endothelium in laser refractive surgery (LRS) is currently being addressed in the assessment of postoperative corneal edema risk. : Changes in corneal endothelial cell density and morphology after LRS were evaluated based on a systematic review of current studies. The results of a literature search in the PubMed, Science Direct, Google Scholar, and the Web of Science databases, as well as a manual search, were selected for the final review according to the PRISMA 2020 flow diagram. : We included 24 prospective clinical trials in the review: surface ablation (twelve), LASIK and FemtoLASIK (two), femtosecond lenticule extraction (two), and comparable studies (eight). Endothelial cell density was determined by specular or in vivo confocal microscopy. In most studies, no statistically significant differences were found between preoperative and postoperative endothelial parameters. In nine studies, the changes were statistically significant, but no vision-threatening complications occurred, and no serious corneal complications developed in any eyes during the follow-up period. : Based on collected data, laser keratorefractive surgery appears not to exert a significant effect on the corneal endothelium.
PubMed: 38541890
DOI: 10.3390/jcm13061665 -
Arquivos Brasileiros de Oftalmologia 2024To investigate the association of pre-photorefractive keratectomy Schirmer-1 test value with post-photorefractive keratectomy central corneal epithelial thickness,...
PURPOSE
To investigate the association of pre-photorefractive keratectomy Schirmer-1 test value with post-photorefractive keratectomy central corneal epithelial thickness, ocular surface disease index score, and uncorrected distance visual acuity.
METHODS
Patients were categorized according to preoperative Schirmer-1 value: the normal Schirmer Group (n=54; Schirmer-1 test value, >10 mm) and the low Schirmer Group (n=52; Schirmer-1 test value, between 6 and 10 mm). We analyzed ablation depth, visual acuity, result of Schirmer-1 test (with anesthesia), tear film break-up time, ocular surface disease index score, central corneal epithelial thickness, and spherical equivalent refraction.
RESULTS
We found significant differences between the groups in Schirmer-1 test value, tear film break-up time, and ocular surface disease index score, both preoperatively and postoperatively (p<0.001). The preoperative central corneal epithelial thicknesses of the two groups were similar (p>0.05). After photorefractive keratectomy, the Schirmer-1 test value and spherical equivalent refraction decreased in both groups (p<0.05), and ocular surface disease index scores and central corneal epithelial thickness values increased in the low Schirmer Group (p<0.001) but not in the normal Schirmer Group (p>0.05). The postoperative central corneal epithelial thicknesses of the low Schirmer Group were significantly higher than those of the normal Schirmer Group (p<0.001). Postoperative uncorrected distance visual acuity did not differ significantly between the two groups (p>0.05).
CONCLUSIONS
In patients with low Schirmer-1 test values before photorefractive keratectomy, the corneal epithelium thickened and ocular surface complaints increased during the postoperative period. However, changes in the corneal epithelium did not affect the postoperative uncorrected distance visual acuity. To reduce postoperative problems on the ocular surface in these patients, we recommend that dry eye be treated before photorefractive keratectomy.
Topics: Humans; Photorefractive Keratectomy; Myopia; Visual Acuity; Refraction, Ocular; Epithelium, Corneal; Lasers, Excimer
PubMed: 38537048
DOI: 10.5935/0004-2749.2023-0049 -
Vision (Basel, Switzerland) Mar 2024The type and nature of refractive surgery procedures has greatly increased over the past few decades, allowing for almost all patient populations to be treated to... (Review)
Review
The type and nature of refractive surgery procedures has greatly increased over the past few decades, allowing for almost all patient populations to be treated to extremely high satisfaction. Conventional photorefractive keratectomy involves the removal of the corneal epithelium through mechanical debridement or dilute alcohol instillation. An improvement to this method utilises laser epithelial removal in a single-step process termed transepithelial photorefractive keratectomy (transPRK). We explore the history of transPRK from its early adoption as a two-step process, identify different transPRK platforms from major manufacturers, and describe the role of transPRK in the refractive surgery armamentarium. This is a narrative review of the literature. This review finds that TransPRK is a safe and effective procedure that works across a variety of patient populations. Though often not seen as a primary treatment option when compared to other corneal-based procedures that offer a faster and more comfortable recovery, there are many scenarios in which these procedures are not possible. These include, but are not limited to, cases of corneal instability, previous refractive surgery, or transplant where higher-order aberrations can impair vision in a manner not amenable to spectacle or contact lens correction. We discuss refinements to the procedure that would help improve outcomes, including optimising patient discomfort after surgery as well as reducing corneal haze and refractive regression.
PubMed: 38535765
DOI: 10.3390/vision8010016 -
The British Journal of Ophthalmology Apr 2024To evaluate the bilateral changes in the sub-basal nerve plexus of the cornea and ocular surface function after unilateral small incision lenticule extraction (SMILE)...
AIMS
To evaluate the bilateral changes in the sub-basal nerve plexus of the cornea and ocular surface function after unilateral small incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (tPRK) procedures.
METHODS
34 patients were enrolled in the study and underwent unilateral SMILE (21 of 34 patients) or unilateral tPRK (13 of 34 patients). Complete ophthalmic examinations, tear film function tests and Cochet-Bonnet esthesiometry were conducted to assess the effects of the surgeries on the corneal nerves and tear function. Morphological changes were assessed using in vivo confocal microscopy to evaluate the corneal sub-basal nerve plexus and dendritic cells. ELISA was used to measure the tear neuromediators. Clinical and morphological data at each follow-up point were compared with preoperative baseline values.
RESULTS
All patients who underwent unilateral SMILE or tPRK procedures exhibited bilateral corneal nerve degenerative changes, decreased corneal sensitivity, worsening of dry eye symptoms and changes in bilateral tear neuromediators. In the SMILE group, bilateral corneal sensitivity was positively correlated with corneal nerve fibre length and negatively correlated with dendritic cell area. The dry eye severity was negatively correlated with corneal sensitivity. Tear levels of substance P and nerve growth factor were positively correlated with mean dendritic cell area and dry eye severity, but negatively correlated with corneal sensitivity. In the tPRK group, bilateral corneal sensitivity was positively correlated with corneal nerve fibre density.
CONCLUSIONS
Unilateral refractive surgery may bilaterally affect the morphology and function of corneal nerves and ocular surface status postoperatively.
PubMed: 38527771
DOI: 10.1136/bjo-2023-324358 -
Diagnostics (Basel, Switzerland) Feb 2024(1) Background: Laser-assisted refractive surgery is a safe and effective surgical correction of refractive error. For most patients, both the newer Trans-PRK and the...
(1) Background: Laser-assisted refractive surgery is a safe and effective surgical correction of refractive error. For most patients, both the newer Trans-PRK and the established LASIK technique can produce the required surgical correction, sparking the question of which technique should be opted for. (2) Methods: The study prospectively evaluated 121 patients (230 eyes) for at least one month postoperatively; 66 patients (126 eyes) and 45 patients (85 eyes) returned for 6 months and 1 year follow-up. (3) Results: No statistical difference was recorded at 1 week or 1 month post-operation. At 6 months, a difference was found for spherical diopters (Trans-PRK -0.0476 ± 0.7012 versus FS-LASIK +0.425 ± 0.874, = 0.004) and spherical equivalent (Trans-PRK -0.1994 ± 0.0294 versus FS-LASIK +0.225 ± 0.646, = 0.025) but not for CYL D (Trans-PRK -0.3036 ± 0.5251 versus FS-LASIK -0.4 ± 0.820, = 0.499). Uncorrected visual acuity was better for Trans-PRK 6 months post-operation (UCVA logMAR 0.02523 versus 0.0768 logMAR; = 0.015 logMAR). At 1-year, Trans-PRK was favored for spherical diopters (Trans-PRK -0.0294 ± 0.6493 versus FS-LASIK +0.646 ± 0.909, < 0.001) and spherical equivalent (Trans-PRK -0.218 ± 0.784 versus FS-LASIK 0.372 ± 1.08, = 0.007). Overall speed in visual recovery, variance of results and surgically induced astigmatism were in favor of Trans-PRK. (4) Conclusions: The study reported improvements for Trans-PRK patients, with both techniques found to be safe and effective.
PubMed: 38472953
DOI: 10.3390/diagnostics14050481 -
Photorefractive Keratectomy in Student Naval Aviators: Outcomes of the U.S. Navy Accessioning Study.Journal of Refractive Surgery... Mar 2024To present the outcomes of the U.S. Navy photorefractive keratectomy (PRK) accessioning study conducted between 2000 and 2005 that helped lead to the acceptance of laser...
PURPOSE
To present the outcomes of the U.S. Navy photorefractive keratectomy (PRK) accessioning study conducted between 2000 and 2005 that helped lead to the acceptance of laser vision correction within the U.S. aviation industry.
METHODS
In this prospective masked study, a total of 301 students who had PRK and underwent naval flight training were compared to 4,368 untreated peers. Three training pipelines were compared: propeller/jet transport, jet fighters, and helicopters. The evaluated metrics were flight and academic performance (assessed for the primary and advanced stage of the training as normalized Navy Standard Score [NSS]), as well as the student attrition rate from training.
RESULTS
The attrition rate was lower in the PRK group compared to controls (15.9% vs 23.2%; = .004). In the primary stage of training, students who had PRK outperformed controls in flight training performance in the propeller/jet transport pipeline (average NSS after PRK: 52.4 ± 7.5 vs controls: 50.7 ± 6.4, = .02), but the flight performance in the jet fighter and helicopter pipelines was comparable between the two groups. Academic performance in the primary stage of training was approximately 7% to 13% higher in students who had PRK for all training pipelines. During the advanced training stage, there was no difference in the flight performance between the groups in any of the presented pipelines. Academic performance was significantly better for students who had PRK in the helicopter pipeline (51.2 ± 11.0 vs 46.7 ± 11.7 < .001) but comparable between the two groups in the remaining pipelines.
CONCLUSIONS
Refractive surgery did not have adverse effects on flight performance metrics. Pilots who had PRK had comparable or better outcomes than their untreated peers. .
Topics: Humans; Photorefractive Keratectomy; Visual Acuity; Prospective Studies; Pilots; Students; Lasers, Excimer; Refraction, Ocular
PubMed: 38466768
DOI: 10.3928/1081597X-20240131-02 -
Journal of Cataract and Refractive... Jul 2024To explore visual outcomes in patients with extreme myopia receiving an implantable collamer lens (ICL) at -18.00 diopters (D), with central port, followed by bioptics...
PURPOSE
To explore visual outcomes in patients with extreme myopia receiving an implantable collamer lens (ICL) at -18.00 diopters (D), with central port, followed by bioptics by laser vision correction (laser in situ keratomileusis [LASIK] or photorefractive keratectomy [PRK]) to address residual myopia or myopic astigmatism.
SETTING
Clínica Baviera (Aier Eye Hospital Group), Bilbao, Spain.
DESIGN
Retrospective analysis of cases.
METHODS
The study assessed uncorrected distance visual acuity, corrected distance visual acuity (CDVA), predictability, safety, efficacy, and patient satisfaction after implantation of the ICL and bioptics. The model implanted was V4c and EVO, with a correction of -18.00 D. Bioptics were performed at least 3 months after implantation, and patients were followed up for at least 3 months after LASIK or PRK.
RESULTS
The analysis included 125 eyes from 90 patients. Of these, 51.2% underwent LASIK and 48.8% PRK. Mean time from implantation to bioptics was 5.9 ± 9.4 months. Patients were followed up for a mean of 40.2 ± 37.9 months after bioptics. Median manifest refractive spherical equivalent was -2.89 D before bioptics and -0.49 D after. Median CDVA was 0.18 logMAR before bioptics and 0.17 after. The mean safety and efficacy indices were 2.22 ± 1.88 and 2.06 ± 1.85, respectively.
CONCLUSIONS
Visual outcomes and safety indices after ICL implantation and subsequent LASIK or PRK in patients with extreme myopia are excellent.
Topics: Humans; Visual Acuity; Retrospective Studies; Keratomileusis, Laser In Situ; Lens Implantation, Intraocular; Photorefractive Keratectomy; Phakic Intraocular Lenses; Male; Female; Adult; Refraction, Ocular; Lasers, Excimer; Young Adult; Patient Satisfaction; Myopia; Middle Aged; Myopia, Degenerative; Astigmatism; Treatment Outcome
PubMed: 38446490
DOI: 10.1097/j.jcrs.0000000000001438