Corneal Topographic Changes Research Articles

Evaluation of visual quality parameters after Descemet membrane endotelial keratoplasty (DMEK)

Purpose and ObjectivesTo evaluate progressive changes in visual quality parameters in patients who underwent DMEK for Fuchs endotelial dystrophy (FED), and to compare the visual quality results with healthy controls without corneal pathology.MethodsFourteen eyes with FED who underwent DMEK were evaluated for corneal topographic changes using Pentacam (OCULUS, Iberia SL), preoperatively, at 1 month and at 6 months after surgery. Mean keratometry (Km), corneal density (1‐2 mm, central and total), high order aberrations (HOA), low order aberrations (LOA) and total aberrations (total RMS) were analyzed in the anterior and posterior cornea. Fourteen healthy subjects were evaluated using the same protocol and compared with the patient's final evaluation data.ResultsSignificant improvement was observed in patients at 1 month after surgery in the posterior Km (p=0.005), central posterior density (p=0.034), 1‐2 mm posterior density (p=0.006) and central anterior density (p=0.045), and anterior LOA (p=0.026) and total aberrations (p=0.020). After 6 months all densities (anterior and posterior) had improved compared to preoperative results (p<0.05) as well as all posterior aberrations (total, HOA and LOA, p<0.05). Posterior and anterior Km values and corneal densities did not show significant differences compared to healthy subjects (p>0.05). Corneal aberrations (anterior and posterior)remained significantly higher in DMEK subjects (p>0.05)ConclusionsDMEK surgery improves corneal visual quality parameters in FED patients after the first month postoperatively. Corneal density and mean keratometry values are not different from healthy corneas at 6 months after DMEK. However, despite corneal aberrations decrease after surgery they remain higher than those values found in healthy corneas.

Corneal topography and keratometry changes after glued intraocular lens implantation

To analyze the alterations in corneal topography and keratometry (K) after glued transscleral-fixated intraocular lens (IOL) implantation. Dr. Agarwal's Eye Hospital, Chennai, India. Prospective case series. Eyes having glued IOL implantation for aphakia or subluxated lens (>180 degrees) were included. Preoperative autorefractometer and corneal topography was performed. Intraoperative parameters, namely the type, position, and incision size, flap position, and number of sutures were noted. The mean corneal curvature in a steep meridian (maximum K), flat meridian (minimum K), simulated K, pachymetry, and surgically induced astigmatism (SIA) were analyzed. This study evaluated 16 eyes with aphakia and 15 eyes with a subluxated over a mean follow-up of 12months±6 (SD). There was a significant reduction in mean simulated K (P=.014) after surgery. The maximum K decreased significantly (P=.002), from 44.85±2.83 diopters (D) preoperatively to 44.47±2.75 D at 6months. The mean SIA was 1.0±0.7 D (range 0.16 to 3.6 D) and the postoperative astigmatism analysis by the Alpins method was negative (-1.8), showing relative flattening after surgery. Multiple regression analysis found no association between postoperative vision and preoperative maximum K, postoperative simulated K, incision size, and number of sutures. There was no correlation between the postoperative simulated K and incision position (P=.674), sutures (P=.881), and scleral flap position (P=.401). Glued transscleral fixation resulted in a reduction in mean corneal curvature in the steep meridian and there was significant change in corneal astigmatism.

Genetic aspects of keratoconus development

Keratoconus (KC) is the most common form of keratoectasia characterized by changes in corneal topography and its thinning, stretching, and protrusion. The hereditary or genetic theory of keratoconus development is widely recognized. To date, a large number of candidate genes have been investigated in patients with KC. One of the most important of them are the gene encoding a homeodomain-containing protein that belongs to the subfamily of paired-like homeodomain proteins (VSX1), superoxidedismutase 1 (SOD1) gene, and the gene of lysyloxidase (LOX). The linkage analysis reveals over 17 chromosomal regions mutations in which can lead to the development of KC. In families with a hereditary form of keratoconus by GWAS analysis, the association of central corneal thickness (CCT) with a number of genetic loci is revealed. Thus, diverse results of genetic studies and a large number of identified chromosomal regions associated with keratoconus, firstly, show marked genetic heterogeneity of the disease and, secondly, are associated with challenges in DNA diagnosis of this disease. However, there are prerequisites that keratoconus belongs to both hereditary and genetically caused diseases and identified genetic variants are specific both to individual populations and to certain ethnic groups in general.

Effects of chalazia on corneal astigmatism

BackgroundA chalazion is a common eyelid disease that causes eye morbidity due to inflammation and cosmetic disfigurement. Corneal topographic changes are important factors in corneal refractive surgery, intraocular lens power calculations for cataract surgery, and visual acuity assessments. However, the effects of chalazia on corneal astigmatism have not been thoroughly investigated. The changes in corneal astigmatism according to chalazion size and location is necessary for better outcome of ocular surgery. The aim of this study is to evaluate changes in corneal astigmatism according to chalazion size and location.MethodsIn this cross-sectional study, a total of 44 eyes from 33 patients were included in the chalazion group and 70 eyes from 46 patients comprised the control group. Chalazia were classified according to location and size. An autokeratorefractometer (KR8100, Topcon; Japan) and a Galilei™ dual-Scheimpflug analyzer (Ziemer Group; Port, Switzerland) were utilized to evaluate corneal changes.ResultOblique astigmatism was greater in the chalazion group compared with the control group (p < 0.05). Astigmatism by simulated keratometry (simK), steep K by simK, total root mean square, second order aberration, oblique astigmatism, and vertical astigmatism were significantly greater in the upper eyelid group (p < 0.05). Astigmatism by simK, second order aberration, oblique astigmatism, and vertical astigmatism were significantly greater in the large-sized chalazion group (p < 0.05). Corneal wavefront aberration was the greatest in the upper eyelid chalazion group, whole area group, and large-sized chalazion group (p < 0.05).ConclusionsLarge-sized chalazia in the whole upper eyelid should be treated in the early phase because they induced the greatest change in corneal topography. Chalazion should be treated before corneal topography is performed preoperatively and before the diagnosis of corneal diseases.

Evaluation of corneal topographic changes and surgically induced astigmatism after transconjunctival 27-gauge microincision vitrectomy surgery.

To evaluate the corneal topographic changes and postvitrectomy astigmatism after 27-gauge (g) microincision vitrectomy surgery (MIVS) by using Pentacam HR-Scheimpflug imaging system. This prospective descriptive study included 30 eyes of 30 patients who underwent 27-g MIVS. All eyes underwent a Pentacam HR examination preoperatively and on the first week, first month and third month postoperatively. The power of the corneal astigmatism, mean keratometry (K m), K 1 and K 2 values and corneal asphericity (Q value) values for the both front and back surfaces of the cornea, index of surface variance (ISV), index of vertical asymmetry (IVA), index of height asymmetry (IHA), index of height decentration (IHD) and higher-order aberrations including coma, trefoil, spherical aberration, higher-order root-mean-square and total RMS were recorded. Additionally, the mean induced astigmatism was estimated by vector analysis. No statistically significant changes were observed in the mean power of corneal astigmatism, mean keratometry, K 1 and K 2 values, corneal asphericity values, ISV, IVA, IHA, IHD and higher-order aberrations on the first week, first month and third month after the operation. The mean surgically induced astigmatism was calculated as 0.23±0.11 D on the first week, 0.19±0.10 D on the first month and 0.19±0.08 D on the third month postoperatively. Minor corneal surface and induced astigmatic changes are expected to result in rapid visual rehabilitation after pars plana vitrectomy with the 27-g MIVS system.

Corneal topographic changes and surgically induced astigmatism following combined phacoemulsification and 25-gauge vitrectomy

To evaluate corneal topographic changes and surgically induced astigmatism (SIA) after combined phacoemulsification and 25-gauge transconjunctival sutureless vitrectomy (25-G TSV). A retrospective study on 96 eyes of 87 patients who underwent combined phacoemulsification and 25-G TSV. The different topographic parameters and SIA were analyzed pre- and postoperatively. There was no significant changes in corneal topographic parameters at different follow up periods. Only surface regularity index changed significantly in the 2nd postoperative week and then returned to baseline values thereafter. Mean SIA gradually decreased to reach 0.12 D by the 6th postoperative month. Corneal surface and astigmatic changes are insignificant in either early or late postoperative periods following combined phacoemulsification and 25-G TSV. The SIA was the minimum among previous reports on sutureless vitrectomy alone or combined with phacoemulsification. Improvement of SIA did not stop at the 3rd postoperative month but it continued till the 6th month postoperatively.

Различия профиля периферического дефокуса после ортокератологической и эксимерлазерной коррекции миопии

A variety of factors that change the topography of the cornea may also induce changes in peripheral refraction. Purpose. The paper is aimed at assessing the peripheral refraction and retinal contour of myopic eyes after FS-LASIK and orthokeratological (Ortho-k) correction. Materials and methods. We examined a total of 30 patients (60 eyes) aging from 28.86 ±2.83 years which included 12 patients (24 eyes) with myopia of -5.11 ± 0.5 D and with an axial length (AL) of 25.04 ±0.33 mm before and 1 month after FS-LASIK surgery, and also included 18 patients (36 eyes) with myopia of -5.4 ± 0.24 D and AL of 25.78 ± 0.2 mm who wore ESA-DL Ortho-k lenses. The peripheral refraction of all the patients was measured using the Grand Seiko Open-field binocular autoref/keratometer and the peripheral eye length was measured using the IOL Master 500 (Carl Zeiss) at 15° and 30o nasally (N) and temporally (T), respectively, from the center of fovea. Results. The peripheral eye length measured before and after FS-LASIK as well as after Ortho-k correction was less in all peripheral zones than in the center, which corresponds to characteristics observed in hyperopic peripheral defocus. Refraction measured after FS-LASIK showed the formation of myopic defocus with a maximum at 30° from the following results: -2.49 D at T15°, -2.5 D at N15°, -6.73 D at T30°, and -7.8 D at N30°. The maximal myopic defocus after Ortho-k correction was detected in the middle periphery from these following results: -4.89 D at T15°, -5.51 D at N15°, -2.92 D at T30° and -2.4 D at N30°. Conclusions. Both procedures induced a significant peripheral myopic defocus. In the first case, the maximum values of defocus were detected in the peripheral zone (30° from the center of the fovea); in the second case, the maximal effect on the middle periphery was identified 15° from the center. Such patterns of peripheral refraction fully coincided with the specific changes in corneal topography after the two procedures. The retinal contour within 30° from the center retained the relative hyperopic defocus characteristic of intact myopic eyes // Russian Ophthalmological Journal, 2017; 1: 31-5. doi: 10.21516/2072-0076-2017-10-1-31-35.

New technique for femtosecond laser creation of clear corneal incisions for cataract surgery

To evaluate the changes in corneal topography and corneal higher-order wavefront aberrations with the use of a new technique in which clear corneal incisions (CCIs) for cataract surgery are created with a femtosecond laser. IRCCS Fondazione G.B. Bietti, Rome, Italy. Prospective randomized case series. Cataract surgery patients were randomized into 2 groups. In the study group, a 3-plane CCI was created with a femtosecond laser. In the control group, the single plane-angled CCI was created manually using disposable knives. Simulated keratometry (K) values and corneal higher-order wavefront aberrations with 3.5mm and 6.0mm pupils were compared between groups. Each group comprised 10 eyes. At 6months, the mean change in K values from preoperatively was 0.16 diopter (D)±0.14 (SD) in the study group and 0.34±0.16 D in the control group, with no differences between groups (P>.05). The manual CCI significantly increased corneal higher-order wavefront aberrations with 3.5mm and 6.0mm pupils (both P<.05). In the study group, corneal higher-order wavefront aberrations increased significantly with a 6.0mm pupil only (P≤.02). The induced changes in corneal higher-order wavefront aberrations were significantly different between groups over both pupil sizes (P<.05). The femtosecond laser-created CCI did not induce significant changes in simulated K or corneal higher-order wavefront aberrations over the mesopic pupil size. The lower amount of induced corneal higher-order wavefront aberrations with the new technique than with manual CCI could be related to the different geometry of the 2 techniques.

Non-Penetrating Femtosecond Laser Intrastromal Astigmatic Keratotomy Performed during Laser-Assisted Cataract Surgery: Results on Keratometric Astigmatism

Purpose: To investigate the efficacy of non-penetrating femtosecond laser intrastromal astigmatic keratotomy (ISAK) in terms of topographic and refractive changes. Methods: Retrospective study including 42 eyes (35 patients) with a corneal astigmatism between 0.5 and 1.5 D. All eyes underwent femtosecond laser-assisted cataract surgery with ISAK for astigmatism management using the Catalys laser system (Johnson & Johnson Vision). Visual acuity, refraction, as well as corneal topographic and corneal endothelial cell density (ECD) changes were evaluated during a 12-month follow-up. Astigmatic changes were analyzed using the Alpins vector method. Results: A significant reduction in manifest cylinder was observed at 1 month postoperatively (p = 0.03), with no significant changes afterwards (p = 0.90). A total of 38.1%, 52.4% and 59.2% of eyes had a manifest cylinder of 0.50 D or lower preoperatively and at 1 and 12 months after surgery, respectively. A significant reduction was found in topographic astigmatism at 1 month postoperatively (p

Effect of Pupil Size on Wavefront Refraction during Orthokeratology.

It has been hypothesized that central and peripheral refraction, in eyes treated with myopic overnight orthokeratology, might vary with changes in pupil diameter. The aim of this work was to evaluate the axial and peripheral refraction and optical quality after orthokeratology, using ray tracing software for different pupil sizes. Zemax-EE was used to generate a series of 29 semi-customized model eyes based on the corneal topography changes from 29 patients who had undergone myopic orthokeratology. Wavefront refraction in the central 80 degrees of the visual field was calculated using three different quality metrics criteria: Paraxial curvature matching, minimum root mean square error (minRMS), and the Through Focus Visual Strehl of the Modulation Transfer Function (VSMTF), for 3- and 6-mm pupil diameters. The three metrics predicted significantly different values for foveal and peripheral refractions. Compared with the Paraxial criteria, the other two metrics predicted more myopic refractions on- and off-axis. Interestingly, the VSMTF predicts only a marginal myopic shift in the axial refraction as the pupil changes from 3 to 6 mm. For peripheral refraction, minRMS and VSMTF metric criteria predicted a higher exposure to peripheral defocus as the pupil increases from 3 to 6 mm. The results suggest that the supposed effect of myopic control produced by ortho-k treatments might be dependent on pupil size. Although the foveal refractive error does not seem to change appreciably with the increase in pupil diameter (VSMTF criteria), the high levels of positive spherical aberration will lead to a degradation of lower spatial frequencies, that is more significant under low illumination levels.

Peripheral refraction and retinal contour after FS‐LASIK and orthokeratology

PurposeA variety of factors that change the topography of the cornea may also induce changes in peripheral refraction. The paper is aimed at assessing the peripheral refraction and retinal contour of myopic eyes after FS‐LASIK and orthokeratological (OK) correction.MethodsWe examined 30 patients (60 eyes) including 12 patients (24 eyes) aged 28.86 ± 2.83 years with myopia of −5.11 ± 05 D on average, and axial length (AL) = 25.04 ± 0.33 mm before FS‐LASIK and 1 month after it and 18 patients (36 eyes) with myopia of −5.4 ± 0.24 D on average, AL = 25.78 ± 0.2 mm who wore ESA‐DL OK‐lenses. All patients were tested for peripheral refraction on Grand Seiko Open‐field binocular autoref/keratometer and had their peripheral eye length measured on IOL Master 500 (Carl Zeiss) at 15° and 30° nasally (N) and temporally (T) from the center of fovea.ResultsThe peripheral eye length measured before and after FS‐LASIK as well as after OK‐correction was less in all peripheral zones than the central length, which corresponds to hyperopic peripheral defocus. Refraction measured after FS‐LASIK showed the formation of myopic defocus with a maximum at 30°: T15° ‐2.49 D, N15° ‐2.5 D, T30° ‐6.73 D and N30° ‐7.8 D. The maximal myopic defocus after OK‐correction is detected in the middle periphery: −4.89 D at T15°, −5.51 D at N15°, −2.92 D at T30° and 2.4 D at N30°.ConclusionsBoth procedures induce a significant peripheral myopic defocus. In the first case, the maximum values of defocus is detected in the peripheral zone (at 30° from the center of the fovea), in the second case it affects the middle periphery (15° from the center) most of all. Such patterns of peripheral refraction fully coincide with the specific changes in corneal topography after the two procedures. The retinal contour within 30° from the center retains the relative hyperopic defocus characteristic of intact myopic eyes.

Keratoconus correction using a new model of intrastromal corneal ring segments

To evaluate the optical value of a new model of intrastromal corneal ring segments (ICRS) (Keratacx Plus) in patients with keratoconus and to quantify subsequent changes in corneal topography and asphericity. Private practice. Prospective case series. This study comprised patients who had primary keratoconus or keratectasia after laser in situ keratomileusis (LASIK); none wore contact lenses. Rings were implanted through tunnels created manually or with a femtosecond laser. All eyes had clear visual axes and corneal thickness over 450 μm at the incision site. Preoperative and postoperative pachymetry images were acquired. Results were analyzed using a matched-pair t test and the Kolmogorov-Smirnov test. Twenty-nine eyes (24 patients; mean age 30.1 years ± 10.6 [SD]) were evaluated. The ICRS significantly increased uncorrected and corrected visual acuities from 0.05 to 0.16 and from 0.17 to 0.5, respectively (z = 4.7, P < .001). They reduced the median spherical error from -4.0 to -0.5 diopters (D) (P < .001) and median cylindrical error from -4.4 to -2.5 D (P < .001). All topographic parameters were reduced, including maximum keratometry (K) (49.4 D versus 45.1 D), minimum K (49.4 D versus 45.1 D), mean K (51.4 D versus 48.4 D), astigmatism (-2.0 D versus -0.5 D), and asphericity (eccentricity 0.49 versus 0.23) (all P < .001). The ICRS provided topographic and visual improvement in keratoconus and post-LASIK keratectasia. Variance in surgical outcomes with manual versus femtosecond tunneling and the effect of different ring sizes are yet to be studied.

Hypoxic Corneal Changes following Eight Hours of Scleral Contact Lens Wear

To examine the change in corneal thickness and posterior curvature following 8 hours of miniscleral contact lens wear. Scheimpflug imaging (Pentacam HR; Oculus) was captured before, and immediately following, 8 hours of miniscleral contact lens wear for 15 young (mean age 22 ± 3 years), healthy participants with normal corneae. Natural diurnal variations were considered by measuring baseline corneal changes obtained on a separate control day without contact lens wear. Over the central 6 mm of the cornea, a small but highly statistically significant amount of edema was observed following 8 hours of miniscleral lens wear, after accounting for normal diurnal fluctuations (mean ± standard deviation percentage swelling 1.70 ± 0.98%, p < 0.0001). Posterior corneal topography remained stable following lens wear (-0.01 ± 0.07 mm steepening over the central 6 mm, p = 0.60). The magnitude of posterior corneal topographical changes following lens wear did not correlate with the extent of lens-related corneal edema (r = -0.16, p = 0.57). Similarly, the initial central corneal vault (maximum post-lens tear layer depth) was not associated with corneal swelling following lens removal (r = 0.27, p = 0.33). Although a small amount of corneal swelling was induced following 8 hours of miniscleral lens wear (on average <2%), modern high Dk miniscleral contact lenses that vault the cornea do not induce clinically significant corneal edema or hypoxic-related posterior corneal curvature changes during short-term wear. Longer-term studies of compromised eyes (e.g. corneal ectasia) are still required to inform the optimum lens and fitting characteristics for safe scleral lens wear to minimize corneal hypoxia.

Effect of Pterygium Size on Astgmatism and Corneal Topography Before and After Surgery

Background: Objective: To analyze the association between pterygium size with astigmatism and corneal topography changes before and after surgery. Methods: This study was conducted at Dr. Soetomo General Hospital and Surabaya Eye Clinic on February-June 2013. In 31 eyes of 20 patients with primary pterygium, size of pterygium was measured in millimeters from the limbus (horizontal length) by caliper and the beam of slit lamp microscope. Twenty four eyes with pterygium type 2 and 3 were excised with bare sclera technique and intraoperative MMC application. Astigmat and corneal topography was investigated with the help of Orbscan preoperatively and 4-6 weeks postoperatively. Result: The size of pterygia had a significant correlation on the elevation of the preoperative corneal astigmatism and irregularities (p&lt;0.001). The mean Sim K astigmatism (p=0.005) and irregularity index (&lt;0.001) significantly decreased after pterygium surgery. The mean refractive power significantly increased after the operation (p&lt;0.001). Conclusion: Pterygium leads to significant changes in corneal refractive status, which increase with the increase in the size of pterygia and improve following pterygium surgery. Keywords: Pterygium, astigmatism, corneal topography

The comparison of conjunctival autograft method with fibrin glue and sutured conjunctival autograft method in terms of vision, refraction and corneal topography

Purpose: To compare the results of pterygium surgery done by using the conjunctival autograft method with suture and the outcomes of pterygium surgery done by using the conjunctival autograft method with fibrin glue in terms of visual acuities, corneal astigmatism and corneal topography changes. Methods: 20 eyes were included in this prospective study. The patients were divided into two groups. Sutured conjunctival graft were performed to the first group. Conjunctival graft with Tisseel fibrin glue were performed to the second group. 10 eyes have been assigned for each group. The best corrected visual acuities, slit lamp and corneal topographic (Orbscan II, Bausch&Lomb) examination were performed. Patients were followed up postoperative day 1, in the 1.week and 1. month. Results: . The mean age of patients was 56. It has not been observed that there is a significant difference between the group in which the autograft method with suture has been used and the group in which fibrin glue has been used in terms of postoperative refractive astigmatism(p=0.96) and corneal topographic astigmatism(p=0.93). Conclusions: Sutured conjunctival autograft and fibrin glue methods for pterygium surgery have similar results in terms of visual acuity, refractive and corneal topographic changes. Both methods could be used safe end effective.

Miniscleral lens wear influences corneal curvature and optics.

Transient changes in corneal topography associated with soft and conventional or reverse geometry rigid contact lens wear have been well documented; however, only a few studies have examined the influence of scleral contact lens wear upon the cornea. Therefore, in this study, we examined the influence of modern miniscleral contact lenses, which land entirely on the sclera and overlying tissues, upon anterior corneal curvature and optics. Anterior corneal topography and elevation data were acquired using Scheimpflug imaging (www.pentacam.com) immediately prior to and following 8 h of miniscleral contact lens wear in 15 young healthy adults (mean age 22 ± 3 years, eight East Asian, seven Caucasian) with normal corneae. Corneal diurnal variations were accounted for using data collected on a dedicated measurement day without contact lens wear. Corneal clearance was quantified using an optical coherence tomographer (RS-3000, www.nidek.com) following lens insertion and after 8 h of lens wear. Although corneal clearance was maintained throughout the 8-h lens wear period, significant corneal flattening (up to 0.08 ± 0.04 mm) was observed, primarily in the superior mid-peripheral cornea, which resulted in a slight increase in against-the-rule corneal astigmatism (mean +0.02/-0.15 × 94 for an 8 mm diameter). Higher order aberration terms of horizontal coma, vertical coma and spherical aberration all underwent significant changes for an 8 mm corneal diameter (p ≤ 0.01), which typically resulted in a decrease in RMS error values (mean change in total higher order RMS -0.035 ± 0.046 μm for an 8 mm diameter). There was no association between the magnitude of change in central or mid-peripheral corneal clearance during lens wear and the observed changes in corneal curvature (p > 0.05). However, East Asian participants displayed a significantly greater reduction in corneal clearance (p = 0.04) and greater superior-nasal corneal flattening compared to Caucasians (p = 0.048). Miniscleral contact lenses that vault the cornea induce significant changes in anterior corneal surface topography and higher order aberrations following 8 h of lens wear. The region of greatest corneal flattening was observed in the superior-nasal mid-periphery, more so in East Asian participants. Practitioners should be aware that corneal measurements obtained following miniscleral lens removal may mask underlying corneal steepening.

Biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy.

To determine the biometric and refractive changes after orbital decompression in Korean patients with thyroid-associated orbitopathy (TAO). Retrospective, observational study (between October 2012 and September 2014) was performed. Patients with TAO undergoing orbital decompression for stable proptosis received ophthalmic examinations, including Hertel exophthalmometry, A-scan biometry, autorefraction measures, corneal topography, and wavefront aberration measures, before orbital decompression and again 2 months after surgery. Included in the study were 43 eyes from 23 patients. The mean exophthalmometric value decreased by 4.1 mm 2 months after orbital decompression (P<0.001). On average, axial length (AL) increased significantly by 0.08 mm (P<0.001); specifically, 37 (86%) of the 43 eyes had increased AL. Whereas anterior chamber depth and lens thickness showed no significant changes (P=0.086 and P=0.905, respectively), the mean spherical refraction and spherical equivalent (SE) decreased by 0.35 and 0.48 D, respectively (P=0.008 and P<0.001, respectively). However, cylindrical refraction and axis showed no significant changes (P=0.057 and P=0.218, respectively). The changes in AL and SE were significantly correlated (R=-0.411, P=0.009). Notably, there were no changes in corneal topography or wavefront aberration after orbital decompression. TAO patients who underwent orbital decompression showed myopic refractive change via increase in AL. Possible refractive changes should be considered in cases of TAO complaining of decreased visual acuity after orbital decompression.

Influence of involuntary eyelid spasms on corneal topographic and eyelid morphometric changes in patients with hemifacial spasm

Background/aimsIn patients with hemifacial spasm (HFS), treatment relieves eyelid spasms on the affected side, thus changes in corneal topography and eyelid morphometry may be observed after treatment. We aimed to...

Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study.

To evaluate in a pilot study the visual, refractive, corneal topographic, and aberrometric changes after wavefront-guided LASIK or photorefractive keratectomy (PRK) using a high-resolution aberrometer to calculate the treatment for aberrated eyes. Twenty aberrated eyes of 18 patients undergoing wavefront-guided LASIK or PRK using the VISX STARS4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Inc., Santa Ana, CA) were enrolled in this prospective study. Three groups were differentiated: keratoconus post-CXL group including 11 keratoconic eyes (10 patients), post-LASIK group including 5 eyes (5 patients) with previous decentered LASIK treatments, and post-RK group including 4 eyes (3 patients) with previous radial keratotomy. Visual, refractive, contrast sensitivity, corneal topographic, and ocular aberrometric changes were evaluated during a 6-month follow-up. An improvement in uncorrected (UDVA) and corrected visual acuity (CDVA) associated with a reduction in the spherical equivalent was observed in the three groups, but was only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). All eyes gained one or more lines of CDVA after surgery. Improvements in contrast sensitivity were observed in the three groups, but they were only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). Regarding aberrations, a reduction was observed in trefoil aberrations in the keratoconus post-CXL group (P = .05) and significant reductions in higher-order and primary coma aberrations in the post-LASIK group (P = .04). Wavefront-guided laser enhancements using the evaluated platform seem to be safe and effective to restore the visual function in aberrated eyes.

Changes in straylight and densitometry values after corneal collagen crosslinking

To evaluate the change in backward-directed and forward-directed corneal straylight in eyes after corneal collagen crosslinking (CXL) and its correlation with corrected distance visual acuity (CDVA) and changes in corneal topography. Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. Retrospective cohort study. Following the Dresden protocol, corneal CXL was performed in eyes with progressive keratoconus. Corneal light scattering was evaluated using densitometry measurements from different corneal layers and zones obtained using Scheimpflug tomography (Pentacam HR). Retinal straylight values were measured using the C-Quant device. The CDVA was recorded during each follow-up examination. Changes in corneal topography were measured using Scheimpflug tomography. The study evaluated 31 eyes of 31 patients. The mean densitometry of different corneal layers and in 3 different zones increased 3 months postoperatively and decreased thereafter. The mean densitometry in the 0.0 to 2.0 mm zone remained statistically significantly elevated after 12 months (P < .05). The mean preoperative retinal straylight was 1.14 log(s) ± 0.28 (SD). The mean straylight peaked after 1 month and then decreased continuously but remained elevated after 1 year at 1.26 ± 0.21 log(s). There was an increase in CDVA and flattening of the steepest keratometry (K) value (maximum K). Eyes with the greatest maximum K reduction also had the highest densitometry values. Crosslinking-induced stromal changes resulted in an increase in densitometry, especially in the anterior stroma of the central (0.0 to 2.0 mm) zone. These changes correlated with an increase in retinal straylight but not with the postoperative CDVA values.