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Vestnik Oftalmologii 2018The article reviews modern clinical, morphological, and genetic aspects of corneal dystrophies based on the most recent international classification updated in 2015.... (Review)
Review
The article reviews modern clinical, morphological, and genetic aspects of corneal dystrophies based on the most recent international classification updated in 2015. Corneal dystrophies is a group of slow progressing, non-inflammatory corneal pathologies, most of which are characterized by variability of the associated traits. The existence of such pathologies makes important their differential diagnosis from acute inflammatory processes of various etiology, which require urgent therapy. Conservative treatment suitable for dystrophies is usually associated with disorders of the anterior corneal surface and employ symptomatic tactic (lubricants, epithelizing agents, soft contact lenses). No effective etiopathogenetically targeted treatment is currently known. In cases with significant visual acuity decrease, it is possible to perform phototherapeutic keratectomy, abrasive polishing of Bowman's membrane with diamond bur and various types of keratoplasty depending on the depth of involvement.
Topics: Cornea; Corneal Dystrophies, Hereditary; Corneal Transplantation; Humans; Lasers, Excimer; Photorefractive Keratectomy
PubMed: 30499549
DOI: 10.17116/oftalma2018134051118 -
Journal of Cataract and Refractive... May 2021Twenty-eight case reports and case series published between 2000 and 2019 concerning laser refractive surgery in patients with corneal dystrophies, resulting in 173 eyes...
Twenty-eight case reports and case series published between 2000 and 2019 concerning laser refractive surgery in patients with corneal dystrophies, resulting in 173 eyes from 94 patients, were included in this systematic review. Best results were achieved in posterior corneal polymorphous and Cogan dystrophy. Unfavorable results were found in Avellino dystrophy and Fuchs endothelial corneal dystrophy (FECD). Photorefractive keratectomy was not indicated in Meesmann and Avellino dystrophy. Laser in situ keratomileusis was indicated in posterior polymorphous corneal dystrophy but not in FECD, Avellino, or Cogan dystrophy. Small-incision lenticule extraction and other dystrophies such as lattice, fleck, Lisch, or François did not achieve enough scientific evidence to report any recommendation.
Topics: Cornea; Corneal Dystrophies, Hereditary; Humans; Keratomileusis, Laser In Situ; Lasers, Excimer; Photorefractive Keratectomy
PubMed: 33149045
DOI: 10.1097/j.jcrs.0000000000000468 -
Journal of Glaucoma Jun 2022All devices evaluated in this study showed a significant underestimation in intraocular pressure (IOP) measurement after myopic photorefractive keratectomy (PRK),...
PRCIS
All devices evaluated in this study showed a significant underestimation in intraocular pressure (IOP) measurement after myopic photorefractive keratectomy (PRK), Goldmann tonometer more than others. Corneal biomechanics indicated a different influence on the different kinds of tonometry.
PURPOSE
The aim was to investigate the reliability of Goldmann applanation tonometry (GAT), rebound tonometry (RT), ocular response analyzer (ORA), Corvis ST (CST), and dynamic contour tonometry (DCT) in IOP evaluation after myopic PRK.
MATERIALS AND METHODS
One eye of 145 patients who underwent myopic PRK for a refractive defect ranging from -10.25 to -0.50 D (mean -4.69±2.00 D) was included in this retrospective comparative study. A complete eye visit with corneal tomography and IOP measurement with GAT, DCT, ORA, RT, and CST was performed before surgery and at 1, 3, and 6 months follow-up. Values provided by each device were tested and compared at each follow-up. Correlation analyses were run between changes in IOP and the corneal, morphologic and biomechanical parameters were measured after PRK.
RESULTS
GAT, DCT, ORA, RT, and CST showed a significant (P<0.01) underestimation of IOP at 6 months follow-up. GAT showed the greatest underestimation (-14.1%) and stronger correlations with corneal deformation parameter changes, whereas ORA, DCT, and RT appeared to be less conditioned by these variations. At 6 months follow-up DCT, ORA, RT, and CST provided IOP values with nonsignificant differences compared with GAT before PRK.
CONCLUSIONS
Each tested tonometer showed a significant IOP underestimation after myopic PRK. As this was most observed with GAT compared with all devices, we suggest DCT, ORA, RT, or CST to evaluate IOP in these patients following surgery.
Topics: Cornea; Humans; Intraocular Pressure; Myopia; Photorefractive Keratectomy; Reproducibility of Results; Retrospective Studies; Tonometry, Ocular
PubMed: 35394466
DOI: 10.1097/IJG.0000000000002023 -
Journal of Refractive Surgery... Dec 2018To determine how photorefractive keratectomy (PRK) and mitomycin C (MMC) affect corneal nerves and their regeneration over time after surgery.
PURPOSE
To determine how photorefractive keratectomy (PRK) and mitomycin C (MMC) affect corneal nerves and their regeneration over time after surgery.
METHODS
Twenty-eight New Zealand rabbits had corneal epithelial scraping with (n = 3) and without (n = 3) MMC 0.02% or -9.00 diopter PRK with (n = 6) and without (n = 16) MMC 0.02%. Corneas were removed after death and corneal nerve morphology was evaluated using acetylcholinesterase immunohistochemistry and beta-III tubulin staining after 1 day for all groups, after 1 month for PRK with and without MMC, and 2, 3, and 6 months after PRK without MMC. Image-Pro software (Media Cybernetics, Rockville, MD) was used to quantitate the area of nerve loss after the procedures and, consequently, regeneration of the nerves over time. Opposite eyes were used as controls.
RESULTS
Epithelial scraping with MMC treatment did not show a statistically significant difference in nerve loss compared to epithelial scraping without MMC (P = .40). PRK with MMC was significantly different from PRK without MMC at 1 day after surgery (P = .0009) but not different at 1 month after surgery (P = .90). In the PRK without MMC group, nerves regenerated at 2 months (P < .0001) but did not return to the normal preoperative level of innervation until 3 months after surgery (P = .05). However, the morphology of the regenerating nerves was abnormal-with more tortuosity and aberrant innervation compared to the preoperative controls-even at 6 months after surgery.
CONCLUSIONS
PRK negatively impacts the corneal nerves, but they are partially regenerated by 3 months after surgery in rabbits. Nerve loss after PRK extended peripherally to the excimer laser ablated zone, indicating that there was retrograde degeneration of nerves after PRK. MMC had a small additive toxic effect on the corneal nerves when combined with PRK that was only significant prior to 1 month after surgery. [J Refract Surg. 2018;34(12):790-798.].
Topics: Acetylcholinesterase; Alkylating Agents; Animals; Cornea; Debridement; Epithelium, Corneal; Female; Lasers, Excimer; Microscopy, Confocal; Mitomycin; Models, Animal; Nerve Regeneration; Photorefractive Keratectomy; Rabbits; Trigeminal Nerve; Wound Healing
PubMed: 30540361
DOI: 10.3928/1081597X-20181112-01 -
International Ophthalmology Apr 2018To compare postoperative visual outcomes and higher-order aberrations (HOAs) following transepithelial photorefractive keratectomy (t-PRK) and mechanical photorefractive...
PURPOSE
To compare postoperative visual outcomes and higher-order aberrations (HOAs) following transepithelial photorefractive keratectomy (t-PRK) and mechanical photorefractive keratectomy (m-PRK).
METHODS
The medical records of patients who underwent photorefractive keratectomy (PRK) were retrospectively evaluated. Forty-five patients were treated with m-PRK, and 45 were treated with t-PRK. Visual acuity, subjective manifest refraction, and corneal topography were analyzed before surgery and 12 months after surgery for both groups. Total HOAs, spherical, coma, and trefoil aberrations were derived from topography data over the 6-mm corneal zone.
RESULTS
In the m-PRK group, the mean preoperative spherical equivalence (SE) changed from -3.15 ± 0.70 D preoperatively to -0.24 ± 0.70 D 1 year postoperatively. Likewise, SE decreased from -3.36 ± 0.63 to -0.25 ± 0.63 D in the t-PRK group 1 year after the surgery. The number of eyes within ± 0.50 D of the target refraction was 89% for m-PRK and 87% for t-PRK groups (p = 0.20). Eighty-four percentage of eyes in the t-PRK group and 80% of eyes in the m-PRK group showed an uncorrected distance visual acuity of 20/25 or better (p = 0.24). Total HOAs, spherical aberration, coma, and trefoil aberrations increased in both groups after surgery, but no statistically significant differences were detected postoperatively among the corneal aberrations.
CONCLUSIONS
t-PRK and m-PRK result in comparable refractive results for the correction of low and moderate myopia. Corneal aberrations induced by t-PRK and m-PRK were similar. Epithelial removal techniques do not affect visual, refractive results, or HOAs in PRK.
Topics: Adult; Corneal Topography; Corneal Wavefront Aberration; Female; Humans; Lasers, Excimer; Male; Middle Aged; Myopia; Photorefractive Keratectomy; Refraction, Ocular; Regression Analysis; Retrospective Studies; Visual Acuity; Young Adult
PubMed: 28349503
DOI: 10.1007/s10792-017-0501-y -
Eye & Contact Lens Mar 2019To compare the visual and refractive outcomes of transepithelial photorefractive keratectomy (Trans-PRK) and sub-Bowman femtosecond-assisted laser in situ keratomileusis... (Comparative Study)
Comparative Study
PURPOSE
To compare the visual and refractive outcomes of transepithelial photorefractive keratectomy (Trans-PRK) and sub-Bowman femtosecond-assisted laser in situ keratomileusis (SBK).
SETTING
University hospital.
DESIGN
Retrospective, comparative study.
METHODS
Two hundred forty patients with myopia and myopic astigmatism underwent SBK (n=157) or Trans-PRK (n=83). The main outcome measures included manifest spherical equivalent refraction (MRSE), logarithm of the minimum angle of resolution uncorrected visual acuity (UCVA), and best-corrected visual acuity (BCVA), which were evaluated at 1 and 3 months postoperatively.
RESULTS
The preoperative mean MRSE was -4.00±1.2 diopters (D) and -4.05±1.36 D (P=0.76) in Trans-PRK and SBK groups, respectively. There was a significant improvement in UCVA after Trans-PRK (1.29-0.00 at 1 month and -0.05 at 3 months; P<0.001 for both) and SBK (1.25 to -0.04 at 1 month and -0.05 at 3 months; P<0.001 for both). Both UCVA and BCVA were better after SBK compared with Trans-PRK at 1 month (-0.07 vs. -0.03; P<0.001) but not at 3 months (-0.08 vs. -0.07; P=0.223). The patients in Trans-PRK group were significantly more hyperopic compared with those in the SBK group at 1 month (0.11 vs. 0.04; P=0.034) and 3 months (0.11 vs. 0.04; P=0.011) postoperatively. Subgroup analysis showed that patients with myopia >3 diopters were more hyperopic at 1 month postoperatively as compared to patients with myopia of ≤3 diopters.
CONCLUSIONS
Both Trans-PRK and SBK are effective procedures to correct mild to moderate myopia and myopic astigmatism. Patients undergoing SBK experience quick visual recovery. Both procedures had no difference in visual outcomes 3 months postoperatively.
Topics: Adolescent; Adult; Cornea; Female; Follow-Up Studies; Humans; Keratomileusis, Laser In Situ; Lasers, Excimer; Male; Myopia; Photorefractive Keratectomy; Refraction, Ocular; Retrospective Studies; Time Factors; Treatment Outcome; Visual Acuity; Young Adult
PubMed: 30067519
DOI: 10.1097/ICL.0000000000000533 -
Eye (London, England) Jun 2023To assess and compare the six-month outcome of the two-step transepithelial phototherapeutic keratectomy- photorefractive keratectomy (PTK-PRK) and the single-step... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
To assess and compare the six-month outcome of the two-step transepithelial phototherapeutic keratectomy- photorefractive keratectomy (PTK-PRK) and the single-step transepithelial PRK for myopia and myopic astigmatism.
METHODS
A prospective randomized study. The study enrolled 100 eyes of 50 patients with mild to moderate myopia or myopic astigmatism stratified into two groups, PTK-PRK (n = 50 eyes) and single step PRK (n = 50 eyes). Primary outcome measures were visual acuity and manifest refraction. Secondary outcome measures were epithelial healing duration, post-PRK pain scores and 3-month postoperative haze grading.
RESULTS
Preoperative characteristics were similar in both groups (p value > 0.05). The mean uncorrected distance visual acuity (UDVA) at 1 week, 1 month, 3 and 6 months was significantly better in the single-step PRK group than in the two-step PTK-PRK group (p < 0.001). The mean manifest sphere, cylinder and spherical equivalent showed a significant difference at all follow up visits in favour of the single-step PRK (p value < 0.001). Epithelial healing duration was faster in single-step PRK (p value < 0.001). Pain scores were significantly lower following single-step PRK at 8 h, 1 day, 3 days (p value < 0.001) but were similar at the 7th day. Haze scores showed no statistical difference between the two groups at 3-month follow-up.
CONCLUSION
The two transepithelial PRK techniques were effective in correcting mild to moderate myopia and myopic astigmatism. However, Single-step transepithelial PRK achieved faster visual recovery, better refractive outcome and shorter epithelial healing time with less post-PRK pain.
CLINICAL TRIALS REGISTRY
(Clinical Trials.gov Identifier): NCT04710082.
Topics: Humans; Photorefractive Keratectomy; Astigmatism; Prospective Studies; Refraction, Ocular; Myopia; Pain; Lasers, Excimer; Treatment Outcome
PubMed: 35864163
DOI: 10.1038/s41433-022-02174-4 -
Journal of Refractive Surgery... Nov 2022To evaluate the safety, efficacy, and predictability of photorefractive keratectomy (PRK) at least 4 years after primary laser in situ keratomileusis (LASIK) and compare...
PURPOSE
To evaluate the safety, efficacy, and predictability of photorefractive keratectomy (PRK) at least 4 years after primary laser in situ keratomileusis (LASIK) and compare it to the United States Food and Drug Administration (FDA) criteria.
METHODS
This retrospective, single-site study compared patients who underwent PRK enhancement from 2014 to 2019 after primary LASIK to those who only underwent primary LASIK without re-treatment from the same time period. Patient demographics and clinical information were compared between the two groups. Visual outcomes and postoperative complications were evaluated in the enhancement group.
RESULTS
A total of 374 eyes with PRK enhancement were compared to 472 without re-treatment. Age, sex, surgical eye, and preoperative sphere, and spherical equivalent (SE) were significantly different between the enhancement and control groups ( < .05). At 12 months post-enhancement, 67% had uncorrected distance visual acuity (UDVA) of 20/20 or better, 98% had UDVA of 20/40 or better, and 0.4% of eyes lost at least two lines of corrected distance visual acuity (CDVA). A total of 83% and 98% of eyes were within ±0.50 and ±1.00 diopters of the target, respectively. Post-enhancement complications (n = 66) included dryness (6.1%), epithelial ingrowth (2.7%), and haze (2.7%).
CONCLUSIONS
Older age at the time of the primary LASIK, female sex, right surgical eye, and more myopic sphere and SE were risk factors for enhancement. Although PRK enhancements are considered off-label procedures, they produce favorable outcomes at 3 and 12 months postoperatively while meeting FDA benchmarks for safety, efficacy, and predictability. .
Topics: Humans; Female; Photorefractive Keratectomy; Keratomileusis, Laser In Situ; Lasers, Excimer; Retrospective Studies; Myopia; Refraction, Ocular; Treatment Outcome
PubMed: 36367261
DOI: 10.3928/1081597X-20221019-01 -
Journal of the College of Physicians... Sep 2023To compare changes in corneal biomechanical properties after laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in low and moderate...
OBJECTIVE
To compare changes in corneal biomechanical properties after laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in low and moderate myopia by Ocular Response Analyzer.
STUDY DESIGN
Quasi-experimental study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi, Pakistan, between September 2020 and April 2022.
METHODOLOGY
Myopic correction was done in forty-six eyes of twenty-three patients by PRK, and forty-seven eyes of twenty-four patients by LASIK. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using Ocular Response Analyzer (ORA), pre-operatively, and then 1, 3, and 6 months, postoperatively. The relationship between the amount of myopia treated and biomechanical properties was also studied.
RESULTS
CRF and CH were decreased significantly after LASIK and PRK. A significantly larger decrease in CRF was observed after LASIK as compared to PRK at 6 months (Mann-Whitney U test: CRF, p = 0.02); however, decrease in CH was not statistically significant between LASIK and PRK at 6 months period (Mann-Whitney U test: CH, p = 0.388). A significant correlation was observed between the changes in biomechanical properties and extent of myopic correction after LASIK and PRK.
CONCLUSION
Biomechanical strength of the cornea was significantly reduced by PRK and LASIK, which was also dependent on the spherical equivalent (SEQ) of myopic correction. A significantly larger change in CRF was observed after LASIK as compared to post PRK.
KEY WORDS
Myopia, Laser in situ keratomileusis, Photorefractive keratectomy, Cornea, Biomechanics.
Topics: Humans; Keratomileusis, Laser In Situ; Photorefractive Keratectomy; Cornea; Myopia; Lasers
PubMed: 37691365
DOI: 10.29271/jcpsp.2023.09.1023 -
Journal of Cataract and Refractive... Apr 2019To study the effect of variables on the accuracy and reliability of the optical pachymeter built into the WaveLight EX500 excimer laser during photorefractive...
PURPOSE
To study the effect of variables on the accuracy and reliability of the optical pachymeter built into the WaveLight EX500 excimer laser during photorefractive keratectomy (PRK).
SETTING
John A. Moran Eye Center, University of Utah, Salt Lake City, USA.
DESIGN
Retrospective case series.
METHODS
A chart review of 352 eyes (181 patients) that had excimer laser PRK was performed. Programmed excimer laser residual stromal bed (RSB) measurements, optical pachymeter measurements after ablation, and Scheimpflug pachymetry measurements (Pentacam) at the 1-year follow-up were compared. Variables included ablation time, preoperative spherical equivalent (SE), 1-year SE, mitomycin-C use, operating room temperature and humidity, and programmed monovision.
RESULTS
The mean programmed RSB was 27 μm greater than the optical pachymetry post-ablation measurement (P < .001). Of patients with a 1-year follow-up, the 1-year Scheimpflug pachymetry RSB was 24 μm greater than the optical pachymetry post-ablation RSB (P < .001). Comparison of the programmed RSB with the optical pachymetry post-ablation RSB showed that the preoperative SE and ablation time had a Pearson correlation coefficient of -0.36 and 0.30, respectively (P < .001). There was no correlation between operating room temperature, humidity, or programmed monovision with these differences.
CONCLUSIONS
The RSB post-ablation values measured by optical pachymetry during PRK were significantly lower than the programmed excimer laser RSB value and 1-year Scheimpflug pachymetry RSB value. Intraoperative pachymetry during PRK underpredicted the actual long-term RSB thickness. The greater temporary drying effect associated with increased ablation time in higher myopic corrections might have caused this error.
Topics: Adult; Aged; Body Temperature; Corneal Pachymetry; Corneal Stroma; Corneal Topography; Female; Follow-Up Studies; Humans; Humidity; Intraoperative Period; Lasers, Excimer; Male; Middle Aged; Operative Time; Organ Size; Photorefractive Keratectomy; Refraction, Ocular; Retrospective Studies; Surgical Flaps; Visual Acuity; Young Adult
PubMed: 30819562
DOI: 10.1016/j.jcrs.2018.11.033