Total Cornea Research Articles

Characteristics of corneal high-order aberrations in adolescents with mild to moderate myopia

BackgroundThis study investigated the characteristics of corneal higher-order aberrations (HOAs) of the anterior surface, posterior surface, and total cornea in adolescents with mild to moderate myopia.MethodsA total of 183 patients with myopia (183 eyes) aged 8 to 18 years were enrolled in this study. The axial length (AL) of the eyes was measured by an IOL-Master, and corneal curvatures (K-values) and HOAs were measured by a Pentacam anterior segment diagnostic analyzer.ResultsResults of this study showed that the anterior, posterior and total corneal horizontal coma Z31 were − 0.1249 ± 0.105 μm, 0.0009 ± 0.001 μm, and − 0.1331 ± 0.116 μm, respectively; the anterior, posterior and total corneal vertical coma Z3− 1 were − 0.0212 ± 0.164 μm, 0.0003 ± 0.043 μm, and − 0.0216 ± 0.168 μm, respectively; and spherical aberration (SA) Z40 values were 0.2244 ± 0.091 μm, 0.1437 ± 0.029 um, and 0.1889 ± 0.090 μm, respectively. Total corneal Z31 was statistically correlated with posterior corneal astigmatism (K2b − K1b) (p = 0.038). Total corneal Z3− 1 was correlated with anterior corneal astigmatism (K2f − K1f) (p = 0.027). Anterior, posterior, and total corneal Z40 were correlated with anterior and posterior corneal curvature (K1f, K2f, K1b, K2b) (p = 0.001). Posterior corneal Z40b was also significantly correlated with AL.ConclusionsIn adolescents with mild to moderate myopia, the posterior corneal surface shape may play a compensatory role in the balance of corneal aberrations, and the posterior corneal SA tended to become less negative as the AL increased. The corneal coma may also play a compensatory role in posterior corneal surface astigmatism, which was valuable for the treatment for improving visual quality. This conclusion still needs to be verified.

Four-Year Outcomes of Small Incision Lenticule Extraction for Extreme High Myopia and Myopic Astigmatism.

Purpose: To evaluate the long-term safety, efficacy, predictability, and stability of small incision lenticule extraction (SMILE) for the treatment of high myopia and myopic astigmatism >−10.0 D.Methods: This was a prospective study that incorporated 35 consecutive patients (35 eyes) undergoing SMILE from September 2015 to March 2016. These patients had a mean preoperative spherical equivalent refraction of −10.06 ± 0.64 D. Patients were followed over a 4-year period and assessed for outcomes including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and corneal topography.Results: At 4 years post-SMILE, respective efficacy and safety indices were 1.01 ± 0.19 and 1.07 ± 0.15. In total, 97% of operated eyes achieved an UDVA of 20/25 or better. ≥1 line was gained for 9 eyes (26%), with 25 eyes (71%) remaining stable. Twenty-four (69%) and 33 (94%) eyes, respectively, were within ±0.50 D and ±1.0 D of target refraction. From 3 months to 4 years postoperatively, a mean refractive regression of −0.22 D (−0.06 D per year) was detected, whereas no significant changes in mean corneal back curvature or posterior central elevation were detected (P = 0.617 and 0.754, respectively). We detected significant increases in higher-order aberrations (HOAs) of the anterior and total cornea (all P < 0.001), with spherical aberrations and vertical coma being particularly common, whereas posterior corneal HOA remained fairly stable (all P < 0.05).Conclusion: SMILE is a safe, effective, predictable, and stable means of correcting high myopia and myopic astigmatism over a 4-year postoperative period.

Pentacam corneal densitometry-guided treatment of adenoviral corneal subepithelial infiltrates: a comparative study between transepithelial phototherapeutic keratectomy and topical tacrolimus

To compare the changes in the measurement of corneal densitometry and total corneal higher-order aberrations (HOAs) between topical tacrolimus and transepithelial phototherapeutic keratectomy (Te-PTK) in the treatment of adenoviral corneal subepithelial infiltrates (SEIs). This is an interventional prospective randomized study, including 63 eyes of 35 patients with symptomatic adenoviral corneal SEIs for at least 6months. All patients underwent previous topical steroid therapy associated with unsatisfactory response and/or complications. Patients were assigned into three groups: (1) Te-PTK group: Te-PTK with MMC 0.02% was performed by a Technolas; Teneo excimer laser; (2) tacrolimus group: tacrolimus 0.03% ointment was applied once daily for 2-6months; the endpoint of treatment was based on the improvement in the corneal densitometry, BCVA, and OSDI; and (3) control group: no intervention was done. BCVA, corneal densitometry, and total corneal higher-order aberrations (HOAs) evaluation using Pentacam HR were done at the baseline, 1week, and then 1, 3, 6, and 12months of the study. The study population was similar between all groups. The mean follow-up was 12.75 ± 0.9months. Bilateral corneal SEI was recorded at 80%. At 12-month follow-ups, the mean BCVA improved in both the Te-PTK and tacrolimus groups without significant changes in the control group. The mean corneal densitometry of the anterior, central, and total cornea decreased significantly in the Te-PTK and tacrolimus groups. HO-RMS and total RMS decreased significantly in the Te-PTK and tacrolimus groups. BCVA, corneal densitometry (anterior, central, and total cornea), and corneal aberrations (total coma, total trefoil, HO-RMS, and total RMS) values were significantly better for the Te-PTK and tacrolimus groups than the control group. There were no statistically significant differences between Te-PTK and tacrolimus groups in terms of BCVA, corneal densitometry, corneal HOA, and the persistence of corneal SEIs. The persistence of corneal SEIs was significantly lower in Te-PTK and tacrolimus groups than the control group. Te-PTK and topical tacrolimus are effective methods for the treatment of adenoviral corneal SEIs improving visual acuity, corneal densitometry, and corneal HOA. The densitometry program of the Pentacam may give an objective guide for the treatment of adenoviral corneal SEIs. ClinicalTrials.gov ID is NCT04267991.

Comparison of visual outcomes after femtosecond laser-assisted LASIK versus flap-off epipolis LASIK for myopia

BackgroundThis study clinically evaluated the visual outcomes after refractive surgery for myopia using femtosecond laser-assisted in situ keratomileusis (femto-LASIK) and flap-off epipolis LASIK (epi-LASIK).MethodsIn this retrospective case series study, 40 eyes of 27 patients were divided into two groups depending on the technique used for refractive surgery. Femto-LASIK and flap-off epi-LASIK flaps were created using femtosecond laser and Epi-K™ epikeratome, respectively. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, manifest refraction, corneal asphericity, and corneal higher-order aberrations (HOAs) were assessed pre- and postoperatively.ResultsThe improvement in logarithm of the minimum angle of resolution (logMAR) UDVA after refractive surgery was statistically significant for both groups (P < 0.001 for all groups); it was significant better in UDVA in femto-LASIK than flap-off epi-LASIK, 0.03 ± 0.06 logMAR (femto-LASIK) and 0.54 ± 0.31 logMAR (flap-off epi-LASIK), at 1 day postoperatively; 0.02 ± 0.05 logMAR (femto-LASIK) and 0.14 ± 0.13 logMAR (flap-off epi-LASIK), at 1 week postoperatively (P < 0.001 and P = 0.019). With regard to the corneal HOAs, the increment in spherical aberration (Z4,0) was greater in flap-off epi-LASIK than femto-LASIK: 0.626 ± 0.232 μm and 0.479 ± 0.139 μm in the front cornea; 0.556 ± 0.227 μm and 0.430 ± 0.137 μm in the total cornea (P = 0.016 and P = 0.017). However, the back corneal HOA changes did not have a significant effect on the total corneal HOA changes.ConclusionFemto-LASIK yielded better early visual outcomes than did flap-off epi-LASIK, but there was no significant difference between the outcomes of the two procedures, 1 week postoperatively.

Invasive Fungal Keratitis as an Uncommon Form of Mucormycosis Leading to Endophthalmitis: Report of Two Cases and Literature Review

This study was conducted to report two cases of fungal keratitis caused by mucormycetes that led to endophthalmitis. Case number 1: a 24-year-old male, with a known case of thalassemia major, presented with chief complaints of painful periorbital edema and redness in the left eye. Intravenous antibiotics were prescribed upon diagnosis of orbital cellulitis, but it progressed to the cornea and sclera and led to endophthalmitis, which was treated with penetrating keratoplasty (PK) combined with deep vitrectomy. Case number 2: a 6-year-old healthy boy presented to the ophthalmology emergency room with ocular pain and redness in his right eye. He had a history of swimming in a river 2 weeks prior to presentation. At the time of presentation, eye examinations showed a dense stromal infiltration with hypopyon. He underwent therapeutic PK due to progression of infiltration to the total cornea and limbus. After the first PK, the patient underwent combined Re-PK and deep vitrectomy, because of recurrence of infection on graft and development of endophthalmitis. The infection relapsed on corneal graft and visual acuity decreased to no light perception. For this patient, enucleation was performed in order to prevent spread of infection to the orbit and brain. Fungal keratitis caused by mucormycetes as an uncommon infection might occur in healthy individuals. Accordingly, timely diagnosis and administration of appropriate antimicrobial agents are vital. In fungal keratitis, patients who have intraocular involvement and are unresponsive to initial antifungal therapy should be evaluated regarding suspicion of mucormycetes.

Corneal higher-order aberrations in phlyctenular keratitis.

To characterize tomographic patterns and quantify corneal higher-order aberrations (HOAs) in eyes with corneal scar due to phlyctenular keratitis. Retrospective consecutive case series. This study included 51 eyes of 38 patients (24 women; 14 men) with corneal scar due to phlyctenular keratitis. HOAs of the total cornea, and of the anterior and posterior surfaces were measured using anterior segment optical coherence tomography (AS-OCT). Corneal tomographic patterns were classified into five types: increased regular astigmatism, ectasia, asymmetric, flattening and minimal change patterns. The correlation between corneal HOAs and visual acuity was evaluated. Mean months from onset was 50.7 ± 74.7 and mean number of recurrences 2.1 ± 1.1 (1-5). Mean logarithm of the minimal angle of resolution (logMAR) was 0.19 ± 0.31. AS-OCT showed ectasia pattern in 16 eyes (31.4%), asymmetric pattern in 12 eyes (23.5%), increased regular astigmatism pattern in 9 eyes (17.6%), flattening pattern in 3 eyes (5.9%) and minimal change pattern in 11 eyes (21.6%). HOAs of the total cornea were 0.57 ± 0.44μm and 1.16 ± 0.77μm within a 4-mm and 6-mm diameter, significantly larger than in normal controls (P < 0.0001). LogMAR visual acuity was significantly correlated with corneal HOAs (4-mm: r = 0.558, P < 0.0001, 6-mm: r = 0.566, P < 0.0001), central corneal thickness (r = - 0.349, P = 0.016), and corneal astigmatism (r = 0.414, P = 0.004), but not with average keratometric value (r = - 0.092, P = 0.537). The most common tomographic pattern was ectasia, followed by a asymmetric pattern in eyes with phlyctenular keratitis. Corneal HOAs were associated with decreased visual acuity in phlyctenular keratitis patients.

Microporous Drug Delivery System for Sustained Anti-VEGF Delivery to the Eye.

PurposeTo describe a novel microporous drug delivery system (DDS) for sustained anti- vascular endothelial growth factor (VEGF) delivery to the eye and to evaluate its efficacy in a corneal injury model.MethodsA macro-porous DDS (1.5 × 1.5 × 4 mm) loaded with 2 mg of bevacizumab was implanted subconjunctivally in three Dutch-belted pigmented rabbits after corneal alkali injury (2N NaOH). Three rabbits received sham DDS. Animals were followed for three months and assessed in vivo and ex vivo for corneal neovascularization (NV), epithelial defect, stromal scarring, endothelial cell loss, and expression of angiogenic and inflammatory markers in the cornea and retina.ResultsAnti-VEGF DDS treatment led to complete inhibition of superior cornea NV and complete corneal re-epithelialization by day 58 whereas sham DDS resulted in severe cornea NV and persistent epithelial defect (9%∼12% of total cornea area) through the end of the study. Histologically, anti-VEGF DDS significantly reduced CD45+ and F4/80 CD11b+ cell accumulation (79%, P < 0.05) in the cornea, ameliorated tumor necrosis factor–α expression (90%, P < 0.05), reduced corneal stromal scarring and prevented corneal endothelial cell loss, as compared to sham DDS. Moreover, anti-VEGF DDS achieved retinal penetration and reduction in retinal VEGF levels at 3 months.ConclusionsUse of subconjunctival anti-VEGF DDS suppresses cornea NV, inflammation, stromal scarring, prevents endothelial cell loss, and abrogates retinal VEGF upregulation in a rabbit corneal alkali burn model. Moreover, it delivers anti-VEGF antibodies to the retina for three months. This delivery platform could enable antibody therapy of other corneal and retinal vascular pathologies.Translational RelevanceWe describe a method for sustained anti-VEGF delivery to the eye for the treatment of ocular injuries.

Multivariate Regression Analysis to Predict Postoperative Refractive Astigmatism in Cataract Surgery.

Purpose To assess the correlation between postoperative refractive astigmatism and preoperative parameters in cataract surgery. Methods Left eyes of 100 consecutive patients scheduled for cataract surgery with a 2.4 mm clear corneal incision were examined prospectively. Refractive astigmatism was measured using an autokerato/refractometer. Corneal astigmatism of the total cornea was calculated using a Scheimpflug camera. The vertical/horizontal component (J0) and oblique component (J45) of refractive and total corneal astigmatism were determined using power vector analysis. Refractive astigmatism at 8 weeks postoperatively was estimated using multivariate linear regression analysis. Independent variables analyzed included age, sex, refractive astigmatism, total corneal astigmatism, sphere, intraocular pressure, corneal thickness, anterior chamber depth, lens thickness, axial length, and pupil diameter. Results Multivariate regression analysis identified total corneal J0 and age as significant contributors to postoperative refractive J0 (P < 0.001 and P=0.029, respectively). The standard partial regression coefficients in the multiple regression analysis were 0.59 and −0.16 for total corneal J0 and age, respectively. Significant contributors to postoperative refractive J45 were total corneal J45 and lens thickness (P < 0.001 and P=0.015, respectively). The standard partial regression coefficients were 0.79 and −0.15 for total corneal J45 and lens thickness, respectively. Conclusion These results suggest that preoperative total corneal astigmatism is the most significant predictor of postoperative refractive astigmatism when performing astigmatism correction in cataract surgery.

Wavefront properties of the anterior and posterior corneal surface after transepithelial photorefractive keratectomy in myopia.

The present study aimed to evaluate the changes of corneal higher-order aberrations (HOAs) after transepithelial photorefractive keratectomy (TransPRK) in patients with myopia. A total of 80 eyes of 80 patients with myopia with or without astigmatism were evaluated. Prior to and 1 year after the surgery, uncorrected and corrected distance visual acuity in logMAR were assessed. Wavefront aberrations on the anterior surface of the cornea, as well as the posterior and total cornea, were measured via Pentacam. The HOA of the anterior surface and total values of spherical and coma aberrations increased significantly (P<0.001). However, HOAs of the anterior surface, and posterior and total values of the trefoil were not significantly changed (P=0.442, 0.805 and 0.936, respectively). A significant correlation of the pre-operative mean spherical equivalent refraction (MSER), astigmatism and central corneal ablation depth (CCAD) with the changes in coma aberration (r=0.268, P=0.016; r=0.260, P=0.020; r=0.323, P=0.004, respectively) and HOA (r=0.554, P<0.001; r=0.312, P=0.005; r=0.583, P<0.001, respectively) of the anterior surface of the cornea was determined. Furthermore, a significant correlation of the pre-operative MSER and CCAD with the changes in spherical aberration of the anterior corneal surface (r=0.462, P<0.001; r=0.510, P<0.001, respectively) was obtained. In conclusion, TransPRK offers an effective option for improving visual function in patients with myopia. The anterior corneal HOA, as well as spherical and coma aberrations, were significantly increased post-operatively. The HOA of the posterior cornea was not significantly changed. The change in the trefoil aberration was significantly correlated with pre-operative astigmatism, but the pre- and post-operative values were not significantly different.

Comparison between color light‐emitting diode corneal topographer and scheimpflug imager in measuring corneal astigmatism and corneal higher order aberrations

AbstractPurposeTo compare corneal astigmatism magnitude, axis, keratometry, and corneal anterior aberrations between the light emitting diode corneal topography analyzer (Cassini) and Scheimpflug Imager (pentacam).MethodsThis prospective study involved 45 eyes of healthy individuals from Seoul St. Mary’s hospital. For each eye, keratometry, astigmatism and its axis of anterior, posterior and total cornea, higher order aberrations were evaluated with a Scheimpflug Imager (Pentacam HR; Oculus, Wetzlar, Germany) and a color‐LED corneal topographer (Cassini; i‐Optics, The Hague, The Netherlands)ResultsAstigmatism magnitude measured using Cassini® and Pentacam® showed no statistically different but anterior and total astigmatic axis were significantly different between two devices (p &lt; 0.05). Anterior and total mean keratometry were statistically significantly different between two devices (p &lt; 0.05) and J0 and J45 vectors of anterior and total cornea were statistically different (p &lt; 0.05). In addition, Cassini® and Pentacam® showed a discrepancy among total corneal astigmatism, total J0 and J45 vectors. Corneal anterior spherical aberration, vertical and horizontal coma, oblique and horizontal trefoil aberrations were not statistically different between 2 devices.ConclusionsAstigmatic axis obtained from the two devices based on different principles showed significantly differences. Astigmatism magnitude was not statistically different but showed a discrepancy between two devices.

Innovative cold atmospheric plasma (iCAP) decreases mucopurulent corneal ulcer formation and edema and reduces bacterial load in Pseudomonaskeratitis

PurposeTo evaluate the effect of application of 3% air in helium cold atmospheric plasma jet, using an inexpensive device termed iCAP, in corneal scratch wound closure in vitro and the treatment of Pseudomonas aeruginosa (P. aeruginosa) keratitis in vivo. MethodsThermal imaging to measure temperature of surfaces to which iCAP was applied and UV energy density delivered by iCAP were measured. Scratch wounds inflicted on in vitro cultures of a human corneal epithelial cell line were treated with iCAP and wound widths at various times post-application were measured. Rabbit eyes infected with P. aeruginosa were treated with iCAP and slit lamp biomicroscope examination conducted to determine corneal health outcomes 25 h post infection. Corneal homogenates were plated on agar and viable bacterial colonies enumerated to determine the effect of iCAP on bacterial load in vivo in P. aeruginosa keratitis. ResultsiCAP was shown to operate in the non-thermal regime and also shown to deliver much lower UV energy density than that necessary to cause harmful effects on ocular tissue. iCAP treatment significantly improved the rate of scratch wound gap closure in vitro in a human corneal epithelial cell line compared to controls. In vivo, iCAP treatment of P. aeruginosa keratitis infection in the rabbit eyes (N = 20) significantly reduced the incidence of corneal ulcer (P = 0.003) and corneal edema (P = 0.011) and significantly improved total cornea health (P = 0.034) compared to untreated (N = 10). Finally, in vivo iCAP treatment of P. aeruginosa keratitis infection in the rabbit eyes (N = 19) significantly reduced bacterial loads (P = 0.012) compared to untreated (N = 9). ConclusionOur results strongly suggest that iCAP treatment was effective in improving corneal epithelial defect closure in vitro, reducing ulcer formation and decreasing inflammation in P. aeruginosa infected corneas in vivo and decreasing bacterial loads in P. aeruginosa infected corneas in vivo which led to improved overall cornea health outcomes in vivo. Further studies to investigate iCAP's safety and efficacy against other infectious microbes responsible for causing ulcerative keratitis, with and without co-treatment with antimicrobial therapies are warranted.

Corneal higher-order aberrations in Stevens-Johnson syndrome and toxic epidermal necrolysis

PurposeTo characterize the topography patterns and quantify corneal higher-order aberrations (HOAs) in the chronic phase of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). MethodsThis retrospective, consecutive case series included 84 eyes of 49 patients in the chronic phase of SJS/TEN. HOAs of the total cornea, and of the anterior and posterior surfaces were measured using anterior segment optical coherence tomography (AS-OCT). Corneal topography patterns were classified into one of the 4 types: ectasia-, asymmetric-, flattening- and minimal change- patterns. ResultsMean logarithm of the minimal angle of resolution (logMAR) was 0.93 ± 0.95. AS-OCT showed ectasia pattern in 16 eyes (19.0%), asymmetric pattern in 28 eyes (33.3%), flattening pattern in 11 eyes (13.0%) and minimal change pattern in 29 eyes (34.5%). The HOAs of the total cornea were 1.23 ± 1.04 μm within a 4-mm diameter, which were significantly larger than those in normal controls (P < 0.0001). LogMAR visual acuity was significantly correlated with corneal HOAs (4-mm: r = 0.793, P < 0.0001, 6-mm: r = 0.798, P < 0.0001) and corneal astigmatism (r = 0.508, P < 0.0001), but not with average keratometric value (r = 0.198, P = 0.065). When the participants were stratified based on corneal opacity, logMAR was significantly correlated with corneal HOAs within a 4-mm diameter in opacity grades 0 (35 eyes, r = 0.649, P < 0.0001), 1 (23 eyes, r = 0.678, P = 0.0004), and 2–3 (26 eyes, r = 0.570, P = 0.0024). Ectasia pattern was derived from either corneal thinning (68.7%) or epithelial hyperplasia (31.3%). ConclusionsThe most common topographic patterns for SJS/TEN were minimal change pattern and asymmetric pattern. Corneal HOAs were associated with decreased visual acuity in SJS/TEN.

Distribution and related factors of corneal regularity and posterior corneal astigmatism in cataract patients.

PurposeTo study the distribution of posterior corneal astigmatism (PCA) and its influencing factors in Chinese patients before cataract surgery.Patients and methodsA retrospective study was conducted in the First Affiliated Hospital of Soochow University, Suzhou, China. In all, this study enrolled 121 eligible eyes of 121 cataract patients. The astigmatism, aberrations and Q value of anterior, posterior and total cornea and anterior segment parameters (ACD, CCT, WTW, ATA) were measured by the Sirius System, and AL was measured by Lenstar LS 900. Cataract was diagnosed using slit-lamp examination.ResultsThe mean age of patients was 67.44±10.66 years old. Mean PCA was 0.31±0.17 (range 0.05–1.09) D and 85.9% eyes had PCA values <0.5 D. With-the-rule (WTR) astigmatism predominated the anterior cornea astigmatism (ACA) (48.8%) and total corneal astigmatism (TCA) (61.2%), while against-the-rule (ATR) astigmatism predominated posterior (86.0%). Significant positive correlation was found between the astigmatic power vector (APV) of ACA and PCA (Pearson correlation=0.318, P<0.001); TCA and PCA (Pearson correlation=0.204, P=0.025); keratometric astigmatism and PCA (Pearson correlation=0.356, P<0.001); this study also found a positive correlation between primary spherical aberration (Z4°) of the total cornea and PCA (Pearson correlation=0.266, P=0.003); primary spherical aberration (Z4°) of the corneal front surface and PCA (Pearson correlation=0.260, P=0.004); total corneal aberrations (Total cornea root mean square [RMS]) and PCA (Pearson correlation=0.327, P<0.001); total corneal higher-order aberrations (Total HOA RMS) (Pearson correlation=0.232, P=0.011); total corneal lower-order aberrations (Total LOA RMS) (Pearson correlation=0.250, P=0.006). A positive linear correlation between Q value of corneal front surface and PCA, either 6 mm pupil diameter (Pearson correlation=0.264, P=0.003) or 8 mm pupil diameter (Pearson correlation=0.184, P=0.043) was found in this study.ConclusionCorneal aberration, Q value (front surface specifically) was essential that we need to take into consideration when we conduct PCA and intraocular lens measurement in clinics.

Impact of Corneal Higher-Order Aberrations on Visual Acuity After Deep Anterior Lamellar Keratoplasty in Treating Keratoconus.

To evaluate the incidence of the Descemet membrane (DM) folds after deep anterior lamellar keratoplasty (DALK) in treating keratoconus. We also evaluated the influence of DM folds and corneal higher-order aberrations (HOAs) on visual acuity after DALK. This retrospective study included 89 consecutive eyes of 87 patients who underwent DALK for the treatment of keratoconus at Tokyo Dental College Ichikawa General Hospital from April 2002 to June 2017. The presence or absence of DM folds was determined by slitlamp microscopy. Visual acuity after DALK was compared between the eyes with and without DM folds. Corneal HOAs of the anterior and posterior surfaces and the total cornea were measured by anterior segment optical coherence tomography. Correlations among the presence of DM folds, corneal HOAs, and visual acuity were analyzed. The Descemet membrane folds developed in 28.1% (25/89) eyes after DALK for the treatment of keratoconus. However, there were no significant differences in postoperative visual acuity between the eyes with and without DM folds at 1, 3, 6, and 12 months (P=0.739, P=0.106, P=0.223, and P=0.186, respectively). The visual acuity at 12 months was significantly correlated with corneal HOAs within a 4-mm diameter (anterior surface: R=0.546, P=0.003; total cornea: R=0.506, P=0.007). Larger corneal HOAs, but not the presence of DM folds, were associated with poor visual acuity after DALK. In treating advanced keratoconus with DALK, it is important to minimize postoperative corneal HOAs, although DALK improves visual acuity by reducing HOAs due to keratoconus.

Fourier Analysis of Corneal Irregular Astigmatism After Small Incision Lenticule Extraction and Comparison to Femtosecond Laser-Assisted Laser In Situ Keratomileusis

Evaluation of spherical component (SC), regular astigmatism (RA), and irregular astigmatism (IA, ie, Asymmetry and Irregularities) 3 years after small incision lenticule extraction (SMILE) and comparison to femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Thirty-two eyes of 21 patients who underwent SMILE for myopia and astigmatism were compared with 32 eyes of 21 patients treated with FS-LASIK. Scheimpflug images were obtained preoperatively and 3 years postoperatively. Fourier analysis of keratometric-derived parameters (SC, RA, Asymmetry, and Irregularities) of the anterior, posterior, and total cornea were evaluated at 4 concentric rings (ring 1, 2 mm diameter; ring 2, 4 mm; ring 3, 6 mm; ring 4, 8 mm) and over the entire 8-mm zone. After FS-LASIK, over the 8-mm zone, the RA and IA of the anterior cornea increased significantly (P ≤ 0.002), whereas SMILE induced an insignificant increase in RA and Asymmetry (P ≥ 0.276) and a decrease in Irregularities (P = 0.770). At the 8-mm zone of the posterior cornea, the Irregularities increased significantly (P = 0.027) after FS-LASIK, whereas SMILE induced no significant changes in the examined variables (P ≥ 0.347). RA and IA of the total cornea increased significantly after FS-LASIK (P ≤ 0.001), whereas SMILE induced an insignificant increase in RA and Asymmetry (P ≥ 0.092) and a significant decrease in Irregularities (P < 0.001). FS-LASIK induced a greater decrease in SC of the total cornea at ring 4 (P = 0.009). FS-LASIK resulted in a greater increase in RA and Irregularities and greater flattening of the midperiphery of the anterior and total cornea compared with SMILE. The posterior cornea remained unaffected after SMILE, whereas more Irregularities were induced after FS-LASIK over the 8-mm zone.

Еfficacy of Combined Treatment of Epithelial and Endothelial Corneal Dystrophy Using Corneal Crosslinking and Automated Posterior Lamellar Keratoplasty

The purpose: to establish a combined approach to the treatment of patients with epithelial and endothelial cornea dystrophy (EED) based on a comparative study of the results of one-step and two-step methods. Patients and methods. The study included 75 patients (81 eyes) with corneal EED, who underwent surgical treatment at the Ufa Eye Research Institute from 2011 to 2016. The patients were divided into two groups — the main group consisted of 43 (46 eyes, 57 %) patients, who underwent the first stage of the CC before surgical treatment of EED, the second stage after 1–12 months — automated posterior lamellar keratoplasty (APLK). In the control group, isolated APLK was performed in 32 (35 eyes, 43 %) patients. Results. After CC (1–10 days) in the main group an increase in corneal thickness due to edema enhancement in the cornea stroma was observed in patients with stage I–III of the corneal EED. After 3 months, a decrease in corneal thickness was recorded in patients of the main group with I-II stages of the disease (p &lt; 0.05), after 6 months — in all stages of the corneal EED compared with the control group (p &lt; 0.05). According to optical coherence tomography (OCT), a decrease in the total cornea thickness in both зфешутеы groups was noted within 12 months after APLK: in the main group from 667 ± 65 μm initially to 594 ± 31 μm, in the control group, where there was a pronounced corneal edema from 787 ± 56 to 612 ± 67 μm. Conclusion. Corneal cross-linking in patients with I–III stages of corneal EED provides improvement of the cornea, manifested in reducing edema and its thickness. It allows to delay the implementation of the automated posterior lamellar keratoplasty without corneal deterioration in patients with stage I up to 6–12 months, in patients with stage II–III up to 3–6 months.

Corneal Higher-Order Aberrations in Eyes With Corneal Scar After Traumatic Perforation.

To evaluate corneal higher-order aberrations (HOAs) in eyes with corneal scar after traumatic perforation and their correlation with visual acuity. This retrospective consecutive case study included 40 eyes of 40 consecutive patients (mean age, 39.2±21.6 years), treated for traumatic corneal perforation at Tokyo Dental College, and 18 normal control eyes. Higher-order aberrations of anterior and posterior corneal surfaces and total cornea were analyzed by swept-source optical coherence tomography. Correlations between corneal HOAs and visual acuity were analyzed. Higher-order aberrations within 4-mm diameter were significantly larger in eyes with corneal perforation (anterior surface, 0.51±0.54 μm; posterior surface, 0.20±0.14; and total cornea, 0.52±0.50) as compared to normal controls (0.10±0.02, 0.02±0.01, and 0.09±0.02, respectively; all P<0.001). Higher-order aberrations within 6-mm diameter were significantly larger in eyes with corneal perforation (anterior surface, 1.15±1.31; posterior surface, 0.31±0.23; and total cornea, 1.09±1.28) as compared to normal controls (0.21±0.06, 0.06±0.01, and 0.19±0.06, respectively; all P<0.001). The most common topography pattern observed was the minimal change pattern (37.5%), followed by asymmetric pattern (30.0%). Visual acuity significantly correlated with corneal HOAs (anterior surface: R=0.646, P<0.001; posterior surface: R=0.400, P=0.033; and total cornea: R=0.614, P<0.001). Corneal scar after traumatic perforations not only induces corneal opacity, but also increases corneal HOAs, which indicates a direct effect on visual acuity.

Higher-order aberration measurements: Comparison between Scheimpflug and dual Scheimpflug–Placido technology in normal eyes

To compare higher order aberrations (HOAs) in normal eyes between a Scheimpflug imaging system (Pentacam HR) and dual Scheimpflug-Placido imaging system (Galilei G4). Emory University, Atlanta, Georgia, and the University of Southern California, Los Angeles, USA. Retrospective case series. Eyes screened for refractive surgery were evaluated sequentially using a Scheimpflug device and a dual Scheimpflug-Placido device. Differences, correlations, and agreement between values for total root mean square (RMS), trefoil, coma, and spherical aberration were analyzed, and Bland-Altman plots were generated. One hundred five eyes of 105 patients (44 men, 61 women) were evaluated. Total RMS, coma, and trefoil were significantly different between groups (all P<.001), while spherical aberration values were not. There was moderate correlation between devices for trefoil (r=0.475 to 0.652), coma (r=0.574 to 0.651), and spherical aberration (r=0.483) and a strong correlation for total cornea RMS (r=0.817). There was no directional bias between groups. The 95% limits of agreement for absolute values was 0.039μm for trefoil at 30 degrees, 0.405μm for trefoil at 0 degree, 0.553μm for horizontal coma, 0.545μm for vertical coma, 0.318μm for spherical aberration, and 0.617μm for RMS. A Scheimpflug imaging device and dual Scheimpflug-Placido imaging device generated statistically different values for total cornea HOAs; however, the correlation between devices was moderate to strong and there was reasonable agreement in all measures for normal eyes. Based on these findings, the devices appear functionally equivalent for clinical use, although caution is warranted for outcomes-based research protocols that report HOAs.

Corneal shape changes of the total and posterior cornea after temporal versus nasal clear corneal incision cataract surgery

AimTo compare changes in the shape and astigmatism of the total and posterior cornea between eyes with a nasal clear corneal incision (CCI) and eyes with a temporal CCI in...

Changes of the anterior, posterior corneal surface and total cornea high order aberrations after SMILE or ICL correction for low and moderate myopia

Changes of the anterior, posterior corneal surface and total cornea high order aberrations after SMILE or ICL correction for low and moderate myopia