Mean Corneal Thickness Research Articles

Topographic changes simulating keratoconus in patients with irregular inferior epithelial thickening documented by anterior segment optical coherence tomography.

PurposeTo present six patients with keratoconus-like topographic changes due to inferior inhomogenous epithelial thickening, demonstrated by AS-OCT epithelium map.Patients and methodsWe present twelve eyes of six patients evaluated in the refractive surgery consultation with Pentacam® HR Scheimpflug rotating camera system, presenting topographical irregularities suggestive of keratoconus. Slit-lamp examination, best-corrected visual acuity, Scheimpflug tomography and anterior segment optical coherence tomography epithelium map (Optovue® ) were conducted and analyzed.ResultsThe mean age was 42 years and the female:male ratio was 2:1. Mean Kmax was 45±2 D. The mean corneal thickness at apex was 560±33 µm and the mean thickness at the thinnest location was 555±34 µm. All patients had an abnormal index of height decentration (IHD) in at least one eye. In all cases, anterior segment OCT demonstrated relative epithelial thickening over the steep area measured by tomography. The mean thickness of the inferior epithelium over the suspicious area was 60±2 µm, whereas the mean thickness of the superior epithelium was 56±2 µm.ConclusionEpithelial irregularity, as measured by anterior segment OCT, should be considered as a possible contributing factor in the appearance of suspicious keratoconus-like topographies.

Diurnal Variation in Corneal Edema in Fuchs Endothelial Corneal Dystrophy

The extent of diurnal variation in corneal edema in Fuchs dystrophy is unknown. We measured corneal thickness and posterior profile over the course of the day using Scheimpflug imaging. Prospective cohort study. Participants with clinically advanced Fuchs dystrophy eyes undergoing endothelial keratoplasty and participants with healthy corneas were assessed around noon the day before surgery and late afternoon, in presumed steady state. After controlled overnight patching to standardize eyelid closure, participants were assessed immediately upon eye opening in hospital the morning of surgery. Directly upon awakening, patients had mean corneal thickness of 663μm (interquartile range [IQR], 625-707) in Fuchs dystrophy (n= 44) and controls (n= 11) had thickness of 557μm (IQR, 527-601). In control corneas, there were no systematic changes with time. In Fuchs dystrophy eyes, corneal thickness decreased after awakening. Ninety-five percent of patients can be expected to have a decrease in corneal thickness over the first 4 hours after awakening between 31μm and 58μm (95% prediction interval). Posterior Q decreased on average by 0.15 (95% confidence interval [CI], 0.07-0.23) and posterior radius of curvature decreased by 0.20mm (95% CI, 0.14-0.27) over the first 4 hours, indicating that edema resolution steepened the central posterior cornea. Beyond 4 hours after awakening, corneas no longer changed considerably in Fuchs dystrophy. Impaired hydration control in clinically advanced Fuchs dystrophy makes measurements of key corneal parameters unreliable directly after eye opening. Beyond the first hours after eye opening, corneal thickness measurements are unlikely to vary more in Fuchs dystrophy eyes than in normal eyes.

Corneal indices following photorefractive keratectomy in children at least 5 years after surgery

To evaluate long-term corneal outcomes in pediatric patients who underwent photorefractive keratotomy (PRK) for the treatment of refractive amblyopia. In this prospective interventional case series, children with refractive amblyopia underwent PRK between January 1, 2007, and December 31, 2011, at Texas Children's Hospital's Department of Ophthalmology, a single tertiary eye center, and were followed for at least 5years after surgery. Main outcome measures were 5+years postoperative indices of corneal thickness, keratometry, degree of corneal haze, and presence or absence of keratectasia. Twelve eyes of 8 subjects aged 3-9years who underwent PRK and were followed for at least 5years were included. The mean PRK treatment dose was 8.46 D for the myopic cohort and 4.49 D for the hyperopic cohort, which removed an average of 72μm of corneal stromal tissue in addition to the 50μm of corneal epithelium that was removed prior to laser ablation. The mean corneal thickness was 563μm preoperatively, which decreased to 441μm immediately following the PRK. The mean corneal thickness 5+years after PRK was stable, at 498μm, because of epithelial regrowth. None of the subjects developed visually significant corneal haze or topographic evidence of keratectasia. In this study cohort, there were no topographic signs of keratectasia or corneal haze in childrentreated with PRK for high refractive error 5years or more after surgery.

Refractive stability following uncomplicated cataract surgery

BackgroundQuality of life may be negatively impacted following cataract surgery if glasses prescription is delayed. This study aims to confirm the refractive stabilisation time in an Australian population to form the basis for suggesting an appropriate timeframe for spectacle prescription.MethodsParticipants (51 female and 35 male) were recruited one day after uncomplicated unilateral cataract surgery using a monofocal intraocular lens. Subjective refraction, automated refraction and central corneal thickness were measured at two, four and six weeks post‐operatively. A short questionnaire assessing the impact of uncorrected near vision on daily activities was collected at two and four weeks.ResultsThere was no significant change in the mean automated or subjective spherical equivalent refraction (peq < 0.001), mean corneal thickness (peq < 0.001), mean uncorrected distance visual acuity (peq < 0.001) or mean uncorrected near visual acuity (peq < 0.001) over the six‐week study period. At week two, 59 per cent of patients stated that their uncorrected near vision affected their ability to perform daily tasks ‘somewhat’ or ‘a lot’, increasing to 75 per cent by week four.ConclusionUncorrected near vision affected quality of life for most participants. All measured visual and ocular parameters were stable from two weeks post‐operatively. Patients need not wait longer than this for spectacle prescription following uncomplicated unilateral cataract surgery.

Keratometric, Pachymetric, and Surface Elevation Characterization of Corneas With Fuchs Endothelial Corneal Dystrophy Treated With DMEK.

To characterize pachymetric, keratometric, and surface elevation parameters in pseudophakic eyes with Fuchs dystrophy that underwent Descemet membrane endothelial keratoplasty (DMEK) and to compare these characteristics with those in normal pseudophakic eyes. Postoperative corneal tomography with a median follow-up of 20 months was evaluated using the Pentacam tomographer on 46 DMEK eyes. Results were compared with data from an age-matched cohort of 46 normal eyes. Parameters included curvature analysis, keratometry values, corneal thickness (CT), pachymetric progression index, Ambrósio relational thickness, posterior elevation, and D-index values. Bonferroni correction was used for multiple comparisons. CT at the apex (mean difference 41 μm; 95% confidence interval 28-54) and CT at the thinnest point (46 μm; 33-60) were statistically significantly lower in the DMEK group (P < 0.001), whereas pachymetric progression index average (0.47; 0.32-0.62), Ambrósio relational thickness maximum (172; 126-228), IHD (0.096; 0.005-0.014), and the global D-index (1.03; 0.51-1.56) were significantly higher in eyes with DMEK (P < 0.001). The mean CT along the vertical and horizontal meridians was significantly lower in the DMEK group within the central 5 mm. A quarter and one half of the DMEK eyes had a CT of less than 500 μm at the apex or at the thinnest point, respectively. Resolution of corneal edema after DMEK was associated with a thinner-than-normal central cornea, steeper pachymetric progression from the thinnest point to the periphery, and some high-end outliers for posterior elevation values. Caution should be exerted in planning corneal refractive surgery for residual refractive errors.

Comparison of rebound tonometry and non-contact airpuff tonometry to Goldmann applanation tonometry.

Purpose:The aim of this study was to compare the intraocular pressure measurements obtained from healthy subjects with the rebound tonometry, non-contact airpuff tonometry, and Goldmann applanation tonometry in different age groups.Methods:A total of 180 eyes of 90 healthy subjects were included in the study. According to the subjects’ ages, the eyes were categorized into three groups: group 1 (age: 7–17 years), group 2 (age: 18–40 years), and group 3 (age: 41–75 years). Intraocular pressure was measured on each subject always in the same order: rebound tonometry, non-contact airpuff tonometry, and Goldmann applanation tonometry. Central corneal thickness values were obtained using ultrasonic pachymetry. One-way repeated-measures analysis of variance, Pearson’s correlation coefficient, and Bland–Altman analysis were used for the statistical assessment.Results:The mean corneal thickness was found to be 604 ± 13 µm, 546 ± 15 µm, and 547 ± 15 µm in group 1, group 2, and group 3, respectively. Non-contact airpuff tonometry was significantly higher than both Goldmann applanation tonometry and rebound tonometry measurements in all groups (p < 0.001, for all). No statistical difference between Goldmann applanation tonometry and rebound tonometry measurements was found in group 1 (p = 0.248), group 2 (p = 0.63), and group 3 (p = 0.126). There was a significant positive correlation in the meaning of intraocular pressure measurements between rebound tonometry and non-contact airpuff tonometry; non-contact airpuff tonometry and Goldmann applanation tonometry; and Goldmann applanation tonometry and rebound tonometry in all groups.Conclusion:As a result, without need for topical anesthesia, fast measurement and ease-of-use rebound tonometry is a reliable alternative to Goldmann applanation tonometry in different age groups.

Correlation of central and peripheral keratometric parameters after corneal collagen cross-linking in keratoconus patients

To evaluate the difference in the central and peripheral keratometric parameters in patients with keratoconus after corneal collagen cross-linking (CXL). Forty-eight eyes of 32 patients (18 males, 16-28years) affected by progressive keratoconus in different stages of evolution underwent CXL using the standard epithelium-off protocol. Corneal thickness and corneal curvature before CXL and after 6 and 12 months using the Sirius tomographer were analyzed. The values of the mean corneal thickness at the corneal apex (CAT), center of the pupil (PCT), thinnest point (CTTL) and along concentric circles of 2, 4, 6, 8, 8.5, 9, 9.5 and 10mm diameter were evaluated; the values of the mean curvature at the corneal apex and at the points in which the inferior, superior, nasal and temporal meridians crossed the above-mentioned concentric circles were also evaluated. The mean preoperative values for CAT, PCT and CTTL were 461.4 ± 30.3, 475.3 ± 30.5 and 441 ± 32.0, respectively. The values after 12months of CXL were 444.6 ± 36.2, 451.6 ± 36.7 and 418.2 ± 41.4. The peripheral corneal thickness at the eight points ranged from 479 to 733 preoperatively. At 12-month post-CXL, the values ranged from 444.6 to 734.1. The mean posterior curvature from apex to periphery ranged from - 4.5 to - 9.1days preoperatively and from - 4.5 to - 9.2days at 12months. These were not statistically significant (ANOVA and unpaired T test). Our data suggest that CXL over an 8-mm zone can stabilize the peripheral cornea. Longer-term follow-up studies on the peripheral cornea after CXL will provide useful information.

Four-year change in ocular biometric components and refraction in schoolchildren: A cohort study

PurposeTo determine 4-year changes of ocular biometric and dioptric components in Iranian children aged 7–11 years following the first phase. Methods468 children were evaluated in the first phase of the study in 2012 and again in 2016–2017. Multi-stage stratified cluster sampling was applied to select the participants. The Topcon autorefractometer and the LENSTAR/BioGraph biometer (WaveLight AG, Erlangen, Germany) were used for cycloplegic refraction and biometry, respectively. All measurements were repeated at 4 years as the baseline assessments. ResultsOf 468 children, 251 (53.6%) were boys. Spherical equivalent (SE) showed a marked myopic shift (P = 0.000) in the second phase which was significantly higher in boys (0.24 vs. 0.18 D) (P < 0.001). Axial length (AL) and anterior chamber depth (ACD) increased by 0.49 ± 0.05 and 0.12 ± 0.02 mm, while lens thickness (LT) and lens power (LP) decreased by 0.08 ± 0.01 mm and 1.59 ± 0.12 D, respectively (P < 0.05). The mean corneal curvature and thickness did not change significantly during 4 years. All biometric component changes were greater in boys. Biometric changes in different age groups showed a decreased LP, increased AL, and increased ACD in most age groups (P < 0.05), while LT and SE did not change significantly in the age groups 9 and 11 years and 8 and 9 years, respectively. Changes in the corneal thickness, diameter, curvature, and refractive astigmatism were not significant in any of the age groups (P > 0.05). ConclusionsStatistical and clinical changes were seen in AL, ACD, LP, and LT. The changes observed in biometric components (AL, ACD, and LT) had a sinus rhythm.

Corneal remodeling and spatial profiles following small incision lenticule extraction.

To evaluate the three-dimensional corneal spatial profiles following small incision lenticule extraction (SMILE) based on corneal asphericity, thickness, and volume. Eighty-three eyes in 83 patients who underwent SMILE were examined before and 1 and 6months after surgery. The asphericity of the anterior and posterior corneal surfaces was analyzed. Corneal volume (CV) was measured in corneal regions measuring 3.0mm, 5.0mm, and 7.0mm in diameter. Mean corneal thickness (CT) values were acquired at the apex (0.0mm) and in four concentric radial zones from the apex (with diameters of 2.0, 4.0, 6.0, and 8.0mm). The mean anterior Q value increased from - 0.32 preoperatively to 0.67 at 1month and 0.62 at 6months postoperatively. The mean posterior Q value decreased from - 0.30 preoperatively to - 0.26 at 1month and to - 0.25 at 6months postoperatively. The CV increased by 0.05 ± 0.06mm3 (1.40%), 0.06 ± 0.11mm3 (0.83%), and 0.09 ± 0.17mm3 (0.73%) along the radial zones with respective diameters of 3.0mm, 5.0mm, and 7.0mm. The CT increased by 6.02 ± 6.48µm (1.36%) at the apex and then decreased with increasing distance from the center, i.e., to 5.52 ± 6.31µm (1.20%) at 2.0mm, 4.72 ± 6.55µm (0.92%) at 4.0mm, 4.47 ± 7.86µm (0.75%) at 6.0mm, and 4.86 ± 10.31µm (0.70%) at 8.0mm. No correlations were observed between changes in CV and CT and refractive fluctuation between 1month and 6months postoperatively. The corneal profile displayed a less oblate shift on the anterior surface; however, the posterior surface showed a slight backward shift during the postoperative period. The CV and CT steadily increased after surgery and mainly within the operative zones. Refraction remained stable postoperatively and was not affected by the corneal remodeling.

Spectral Domain Anterior Segment Optical Coherence Tomography in Fungal Keratitis.

To evaluate the use of spectral domain anterior segment optical coherence tomography (SD-ASOCT) in fungal keratitis. Fifty eyes of 50 patients with fungal keratitis were recruited. Serial ASOCT was performed on days 0, 7, 14, 21, 28, 42, and 56. Corneal thickness (CT) in the infiltrate area, infiltrate thickness (IT), and infiltrate width were measured at each follow-up. The presence of any specific feature on ASOCT was evaluated. Mean CT and IT at presentation were 650.5 ± 108 μm and 401.1 ± 91 μm, which reduced significantly at each follow-up [on days 7, 14, 28, and 42; 626.8 ± 113 μm (P < 0.001) and 367.3 ± 94 μm (P = 0.002), 601.4 ± 109 μm and 344.7 ± 94 μm (P < 0.001), 544.8 ± 103 μm and 305.1 ± 80 μm (P < 0.001), and 522.8 ± 97 μm and 291.4 ± 79 μm (P < 0.001), respectively]. The mean CT and scar depth at complete healing were 496.3 ± 101 μm and 283.2 ± 77 μm, respectively. In 10/50 (20%) eyes, the posterior border of the cornea was not clearly visible because of posterior shadowing; therefore, IT was measured along the maximum visible area of hyperreflectivity, whereas CT was measured just adjacent to the area of shadowing. The infiltrate width was measured in 35 eyes, and the mean values at days 0, 7, 14, 28, 42, and 56 were 5.5 ± 0.8 mm, 4.6 ± 0.7 mm, 4.4 ± 0.6 mm, 4.2 ± 0.6 mm, 4.1 ± 0.6 mm, and 4.1 ± 0.6 mm, respectively. A satellite lesion and endothelial plaque were seen in 30% (15/50) and 44% (22/50) eyes, respectively. ASOCT is a useful adjunct in monitoring fungal keratitis especially in cases with deep stromal involvement and endothelial plaques. In addition, it also provides insight into the activity of keratitis.

Epi-Off versus Epi-On Corneal Collagen Cross-Linking in Keratoconus Patients: A Comparative Study through 2-Year Follow-Up

Aim To evaluate two different techniques of cross-linking: standard epithelium-off (CXL epi-off) versus transepithelial (CXL epi-on) cross-linking in patient with progressive keratoconus. Methods Forty eyes from 32 patients with progressive keratoconus were prospectively enrolled from June 2014 to June 2015 in this nonblinded, randomized comparative study. Twenty eyes were treated by CXL epi-off and 20 by CLX epi-on, randomly assigned, and followed for 2 years. All patients underwent a complete ophthalmologic testing that included uncorrected and best corrected visual acuity, central and peripheral corneal thickness, corneal astigmatism, simulated maximum, minimum, and average keratometry, corneal confocal microscopy, Schirmer I and break-up time (BUT) tests, and the Ocular Surface Disease Index. Intra- and postoperative complications were recorded. The solution used for CXL epi-off comprised riboflavin 0.1% and dextran 20.0% (Ricrolin), whereas the solution for CXL epi-on (Ricrolin TE) comprised riboflavin 0.1%, dextran 15.0%, trometamol (Tris), and ethylenediaminetetraacetic acid. Ultraviolet-A treatment was performed with a UV-X system at 3 mW/cm2. Results In both groups, a significant improvement in visual function (Group 1: baseline 0.36 ± 0.16 logMAR, two-year follow-up 0.22 ± 0.17 logMAR, p=0.01; Group 2: baseline 0.32 ± 0.18 logMAR, 2-year follow-up 0.27 ± 0.19 logMAR, p=0.01) was recorded. Keratometry remained unchanged in both groups. The mean corneal thickness showed a significant reduction (mean difference of corneal thickness: −55 micron and −71 micron, resp.). One-month after treatment, OSDI© reached 13.56 ± 2.15 in Group 1 (p=0.03) and 11.26 ± 2.12 in Group 2 (p=0.04). At confocal microscopy, abnormal corneal nerve alterations were found in both groups. Fibrotic reaction (43.75%) and activated keratocyte (62.6%) were more commonly recorded in Group 1 than in Group 2 (25.0% and 18.75%), with p=0.668 and 0.356, respectively. Conclusion Our findings demonstrate that both procedures are able to slow keratoconus progression. Both treatment modalities are equivalent in terms of results and related complications. CXL epi-on technique is preferable to CXL epi-off since it preserves the corneal thickness and improves visual acuity, also reducing the postoperative ocular discomfort during the study period.

Evaluation of the Effectiveness of Cross-Linking Combined With Photorefractive Keratectomy for Treatment of Keratoconus

To evaluate the effectiveness and safety of combined epithelium-off cross-linking (CXL) with photorefractive keratectomy (CXL Plus) for correction of the myopic and astigmatic components of keratoconus. Seventy-nine eyes of 46 patients who underwent CXL Plus were enrolled in this retrospective, multicenter, noncomparative clinical study. Uncorrected distance visual acuity, corrected distance visual acuity, refraction, keratometry, and pachymetry measurements were recorded preoperatively and at 3, 6, 12, and 18 months during follow-up. The mean (±SD) preoperative uncorrected distance visual acuity and corrected distance visual acuity were 1.00 ± 0.22 logarithm of the minimum angle of resolution (logMAR) and 0.62 ± 0.38 logMAR, respectively, and improved to 0.71 ± 0.36 logMAR and 0.32 ± 0.18 logMAR postoperatively. The mean k value, mean corneal thickness at the thinnest location, and mean myopic and astigmatic components decreased from 46.58 ± 0.97 D, 473 ± 29 μm, 3.65 ± 1.72 D, and 1.83 ± 0.69 D preoperatively to 43.79 ± 1.17 D, 431 ± 38 μm, 1.02 ± 0.78 D, and 1.15 ± 0.26 D, respectively, during follow-up. Eleven eyes had delayed epithelial healing, 2 had stromal opacities, 1 had primary herpes simplex keratitis, and 5 showed progression of keratoconus. CXL Plus improved the refractive status of keratoconus during 18 months of follow-up, despite its potential early postoperative complications of delayed epithelial healing and corneal haze. CXL Plus reduced the myopic component more than the astigmatic component of keratoconus. However, the safety and stability of the procedure were offset by longer-term postoperative complications and a high rate of postoperative progression of keratoconus.

A dose-escalation ex vivo study on the effects of intracameral benzalkonium chloride in rabbits

BackgroundRabbits are currently not a good model for studying diseases of the corneal endothelium because their corneal endothelial cells (CECs) maintain a high proliferative capacity throughout almost all their life. Addressing this particular feature might allow the use of this species for such a purpose. The aim of this study was to evaluate the corneal endothelial injury after intracameral benzalkonium chloride (BAC) injection into rabbit eyes ex vivo, and to establish the most suitable starting dose for an in vivo study aimed at developing an animal model of corneal endothelial disease.ResultsForty rabbit eyes obtained postmortem by transconjunctival enucleation were divided into 8 groups according to the injected compound: Control (no injection), BSS, and increasing BAC concentrations (0.005%, 0.01%, 0.025%, 0.05%, 0.1% and 0.2%). At 0, 6, 24 and 48 h, ophthalmologic examination of the anterior segment, pachymetry and specular microscopy were performed, and corneas were finally vital-stained and observed under the light microscope to assess the CECs morphology and mortality rate. When compared to BSS, CECs density started to decrease significantly at 0.025% BAC concentration, while mean cell area, corneal edema and corneal thickness began to increase significantly at 0.05%, 0.005% and 0.1% BAC concentrations, respectively. Concentrations of 0.05% BAC and above caused significant increases in CECs pleomorphism (decreased hexagonality) and mortality, compared to control and BSS.ConclusionsEx vivo intracameral BAC injection induces corneal endothelial toxicity in rabbits. However, confirmatory in vivo studies are required to develop the desired model, with 0.05% BAC being a suggested starting point.

Reproducibility of corneal, macular and retinal nerve fiber layer thickness measurements using the iVue-100 optical coherence tomography.

To determine the intra-session and inter-session reproducibility of corneal, macular and retinal nerve fiber layer thickness (RNFL) measurements with the iVue-100 optical coherence tomography in normal eyes. These parameters were measured in the right eyes of 50 healthy participants with normal vision. Six scans each for corneal thickness, macular and optic nerve head were taken on one day (intra-session), followed by similar repeated measures on five separate days (inter-session). Reproducibility was computed using intra-class correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability (TRV). For intra-session reproducibility, the ICC, COV and TRV values for mean corneal thickness were 0.924, 2.82%, and 3.06 µm respectively. For the mean macular thickness, they were 0.978, 4.64% and 4.51 µm respectively, while for mean RNFL thickness they were 0.946, 3.19%, and 5.66 µm respectively. Inter-session values for mean corneal thickness were 0.926, 2.65% and 3.48 µm, and 0.916, 2.24% and 2.03 µm for mean macular thickness. For mean RNFL thickness, they were 0.962, 2.21%, and 4.72 µm respectively. There was good reproducibility of all measured parameters. However, mean RNFL thickness measurements were the most reproducible, suggesting that this may be the best parameter to use to determine measured changes over time.

To study the effects of central corneal thickness, axial length, and anterior chamber depth on intraocular pressure

Purpose: The aim of the research project is to study the effects of central corneal thickness (CCT), axial length (AL), and anterior chamber (ACD) depth on intraocular pressure (IOP). Study Period: It was a cross-sectional study and was conducted from February 2015 to June 2015. Methodology: A total of 100 participants of varying age groups were selected from Qassim University clinics who had clinically normal corneas and then were divided into different groups based on their ages. All the participants had no evidence of any ocular disease and both eyes were examined in each participant. Anterior chamber depth (ACD) and CCT were measured with Pentacam (OCULUS). IOP was measured with air puff tonometer. AL was measured by A-scan ultrasonography. Results: Two hundred eyes of one hundred participants were examined. The ages of the participants ranged between 18 and 30 years. Mean age was 23.94 years with ± 2.994 standard deviations The number of emmetropes, myopes, and hypermetropes was 50, 19, and 31, respectively. The mean corneal thickness in the right eye was 541.64 μm (±34.80) and in the left eye, it was 543.46 μm (±33.65). IOP was found to increase with increased CCT and it was statistically significant (P

Accelerated corneal collagen cross-linking in pediatric keratoconus: One year study

PurposeTo evaluate the safety and effectiveness of accelerated corneal collagen crosslinking (CXL) in pediatric keratoconus. DesignProspective non-randomized observational study. Methods33 eyes of 25 children with keratoconus were included. The corneal epithelium was mechanically removed. Next, riboflavin/hydroxypropyl methylcellulose solution) was applied for 10min. Accelerated CXL (10mW/cm2 for 9min), was accomplished. Visual acuity, slit lamp examination, refraction, keratometry readings, pachymetry, anterior and posterior elevations, average progression indices, and Q values were recorded. The follow-up visits were scheduled on one day, 3 days, 7 days, one month and then on 3, 6, 12 months after the procedure. ResultsIt was statistically significant improvement of the mean UAVA, AVA, and the mean corneal astigmatism (P<.0001). The mean corneal thickness showed a significant reduction. The preoperative mean K max reading was reduced from 49.12±3.7D preoperatively to 47.9±3.7D at 12 months. The mean max anterior elevation, average progression index and Q value showed statistically significant improvement. No significant impact on posterior elevation was recorded. Serious complications were not encountered in this study. ConclusionAccelerated CXL shows a stabilization and beneficial clinical outcomes in pediatric keratoconus. It seems an effective and safe procedure in this age group. Effects of accelerated CXL on the posterior corneal surface will need further evaluation.

Transepithelial High-Intensity Cross-Linking for the Treatment of Progressive Keratoconus: 2-year Outcomes

ABSTRACTPurpose: To report 2-year outcomes of transepithelial high-intensity cross-linking (CXL) procedure in the treatment of patients with progressive keratoconus.Methods: Forty-eight eyes of 48 consecutive progressive keratoconus patients who underwent transepithelial accelerated CXL procedure were enrolled in the study. Each patient underwent pre- and postoperative comprehensive ophthalmologic examinations including determination of refractive error as spherical equivalent (SE) and corrected distant visual acuity (CDVA), slit lamp biomicroscopic examination, fundoscopy, and a detailed analysis on a Scheimplug+Placido device (Sirius, CSO, Florence, Italy). The riboflavin solution, which was composed of riboflavin 0.25% with hydroxypropyl methylcellulose (HPMC) and benzalkonium chloride (BAC) (ParaCel, Avedro), was used in the procedure. The cornea was exposed to ultraviolet A light (KXL System, Avedro Inc., Waltham, MS, USA) for 2 minutes and 40 seconds at an irradiance of 45 mW/cm2.Results: The mean age of the patients was 25.9 ± 4.0 (ranging from 18 to 33) years. No significant changes were observed in the mean CDVA, SE, and topographic indices at year 1 and year 2 visits compared to preoperative examination. The mean corneal thickness at the thinnest point was significantly higher at year 1 and year 2 visits than at preoperative examination (p1 = 0.014 and p2 = 0.017, respectively). No intra- or postoperative complications or adverse reactions were observed.Conclusions: Transepithelial high-intensity (irradiance of 45 mW/cm2 for 2 minutes and 40 seconds) CXL using 0.25% riboflavin solution was a safe and effective method to halt the progression of keratoconus for a 2-year follow-up period.

Morphometric changes of corneal endothelial cells following intracameral air for micro perforation of the Descemet Membrane during big-bubble deep anterior lamellar keratoplasty

AimThe aim of this study was to assess the effect of intracameral air on the endothelial cell morphometrics. Patients and methodsThis is a retrospective controlled interventional cohort study of 26 patients (18 males and 8 females) who underwent unilateral deep anterior lamellar keratoplasty (DALK) for moderate keratoconus. The DALK patients were divided into two groups: a treatment group (14), which had micro perforations of the Descemet Membrane (DM) intraoperatively and received intracameral air at the end of the surgery; and an independent control group (12), which had no micro perforation and thus no intracameral air was injected. Postoperative best corrected visual acuity (BCVA), sphere, cylinder, spherical equivalent (SEQ), central corneal thickness, and endothelial cell morphometric features consisted of the endothelial cell density (ECD), polymegathism, and pleomorphism were compared between treatment and control groups. ResultsThe mean BCVA was 0.36±0.36 logMAR in the treatment group and 0.17±0.11 logMAR in the control group (p=0.081), and the mean corneal thickness was 507.86±62.69μm in the treatment group and 525.67±37.54μm in the control group air (p=0.399). Furthermore, the mean sphere was −5.14±4.17D and −1.02±3.29D, the mean cylinder was −3.16±2.20D and −2.88±1.21D, and the mean SEQ was −6.72±4.66D and −2.46±3.14D and in the treatment and control groups respectively (p=0.011, 0.693, and 0.013). As to morphometric features, the mean ECD was 2176.76±549.18cell/mm2 and 2257.30±436.12cell/mm2 in the treatment and control groups respectively (p=0.686), and the mean pleomorphism 0.48±0.09 and 0.54±0.10 in the treatment and control groups respectively (p=0.139). In contrast, the mean polymegathism was 0.37±0.06 and 0.31±0.05 in the treatment and control groups respectively (p=0.009). ConclusionThe presence of air inside the anterior chamber for a short term may not cause further endothelial cell loss and can be safely performed to prevent postoperative Descemet Membrane detachment in case of micro perforations.

Changes in corneal thickness following combined cataract and vitreous surgery

Background We investigated changes in corneal thickness following combined cataract and vitreous surgery and determined whether such changes could be used as a criterion for evaluating the invasiveness of combined surgery.MethodsThis retrospective, consecutive, comparative study examined 35 eyes that had undergone combined cataract and 23-gauge vitrectomy for epiretinal membrane (ERM) (18 eyes) and rhegmatogenous retinal detachment (RRD) (17 eyes). Corneal thickness was measured before, 1 day, 1 week, and 1 and 3 months after the surgery. Measurements were performed at the center and at points 3 mm superior, inferior, nasal and temporal to the center of the cornea.ResultsIn both groups, postoperative corneal thickness at all points showed a significant increase at 1 day after the surgery when compared with the preoperative measurements (p < 0.05, paired t test). At the center and inferior points, the mean corneal thickness in the RRD group was thicker than the mean of the ERM group at 1 day after surgery. With the exception of the inferior point, the postoperative data for both groups showed a significant increase in the corneal thickness at 1 week after surgery compared with the preoperative measurements. At 1 week after surgery, the mean corneal thickness in the RRD group at the center, inferior and temporal points was thicker than the mean of the ERM group.ConclusionsCorneal thickness measurements are useful for assessing the extent of surgical stress that follows combined cataract and vitreous surgery.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1676-9) contains supplementary material, which is available to authorized users.

Descemet Stripping Endothelial Keratoplasty for Fuchs' Endothelial Corneal Dystrophy: Five-Year Results of a Prospective Study

To determine 5-year outcomes of Descemet stripping endothelial keratoplasty (DSEK) for Fuchs' endothelial corneal dystrophy (FECD). Prospective cohort study. Fifty-two eyes of 45 subjects with FECD undergoing primary DSEK. Subjects were examined before and at fixed intervals through 60 months after DSEK. At each visit, graft survival was determined by slit-lamp examination; best spectacle-corrected visual acuity (BSCVA) was measured using the electronic Early Treatment Diabetic Retinopathy Study (ETDRS) protocol; total anterior corneal higher-order aberrations (HOAs) were derived from corneal topography; and corneal backscatter, corneal thickness, and endothelial cell density were measured from confocal microscopy images. Corneal thickness also was measured by ultrasonic pachymetry. Changes after DSEK were analyzed using generalized estimating equation models. Best-corrected visual acuity, HOAs, endothelial cell loss, corneal thickness, and corneal backscatter. Complete 60-month follow-up was possible in 34 eyes. Mean BSCVA±standard deviation improved from 0.45±0.19 logarithm of the minimum angle of resolution (logMAR) (Snellen equivalent, 20/56) before DSEK to0.09±0.13 logMAR (Snellen equivalent, 20/25) at 5 years (P < 0.001). Between 1 and 5 years, BSCVA improved by 0.06 logMAR (or 3 ETDRS letters; 95% confidence interval, 0.05-0.07 logMAR) per year (P < 0.001), and 56% of eyes were 0.1 logMAR (20/25) or better at 5 years. Graft thickness (approximately 155 μm) and corneal thickness (approximately 700 μm) did not change after surgery. Anterior corneal HOAs and backscatter decreased between 1 and 5 years (P ≤ 0.002). Six grafts failed, of which 4 were primary (iatrogenic); mean endothelial cell loss±standard deviation was 55±15% at 5 years. Between 1 and 5 years after DSEK, BSCVA continues to improve such that at 5 years, more than half of eyes see better than 20/25 with a mean total corneal thickness of 700 μm. Improvement in vision is accompanied by continued reduction in corneal haze and aberrations, suggesting ongoing remodeling of the cornea after restoration of endothelial function.