Surface Regularity Index Research Articles

Punctal plugs for treatment of post-LASIK dry eye

To evaluate the efficacy of punctal plugs for patients with post-LASIK dry eye. A prospective study was conducted on 25 eyes of 18 patients who underwent LASIK. All eyes fulfilled the Japanese dry-eye criteria and had not responded to conventional treatment with artificial tears by 1 month postsurgery. They were randomly divided into a plug and a non-plug group. Punctal plugs were inserted into the superior and inferior puncta in the plug group after the 1-month examination. Uncorrected and best corrected visual acuity (UCVA, BCVA), refraction, functional visual acuity (FVA) after 10 s eye opening (FVA 10), surface regularity index (SRI) after 10 s eye opening (SRI 10), corneal sensitivity, Schirmer test, fluorescein staining (FS), tear break-up time (TBUT), and symptoms were compared between the groups 1 and 3 months postsurgery. Changes in these data from 1 to 3 months were also compared between the groups. The values in SRI 10, FS, and TBUT were significantly better in the plug group at 3 months. Changes in the values of UCVA, FVA 10, FS, TBUT, and symptoms between 1 and 3 months improved significantly in the plug group compared with the non-plug group. Our results suggest that punctal occlusion for both puncta is effective for patients with post-LASIK dry eye that cannot be controlled by artificial tears alone. Punctal plugs can improve not only the symptoms and tear function, but also the quality of vision, for example FVA.

Langzeitergebnisse nach perforierender Keratoplastik bei bullöser Keratopathie – Auswirkungen von präoperativem Visus auf die Ergebnisse

The aim of this study was to analyse the long-term functional results of penetrating keratoplasty for pseudophacic bullous keratopathy and Fuchs endothelial dystrophy and to analyse the potential influence of the preoperative visual acuity on the final outcome. This retrospective study describes the postoperative results of 413 patients. 154 of them with bullous keratopathy and 259 patients with Fuchs dystrophy. All received penetrating excimer laser keratoplasty (PK).The results include the examination of the patients 1/3/5/8/ >9 years postoperatively. For analysis the patients were divided in two groups: group I includes patients with a visual acuity ≤0.1 and group II with a visual acuity >0.1. The trephination was performed using a 193 nm excimer laser. The transplanted cornea was fixed by using a double running cross-stitch suture. The outcome measures included best corrected visual acuity (CCV), keratometric equivalent (KEQ), keratometric astigmatism (AST), spherical equivalent (SEQ), refractive cylinder (CYL), best corrected visual acuity (BCVA), surface regularity index (SRI), surface asymmetry index (SAI), potential visual acuity (PVA), pachymetry (PAC), endothelial cell count (ECC), intraocular tension (TEN), topographic equivalent (T-EQ) and topographic astigmatism (T-AST). 5/8 years postoperatively CCV was 0.55/0.58; KEQ was 43.75/45.64 D; SEQ -0.88/-1.88 D; AST was 3.91/4.41 D; CYL was 3.09/3.40 D; ECC was 1230/1080 cells/mm (2); TEN was 13.61/14.36mmHg; PAC was 593.21/579.50µm; SRI was 1.08/0.89; SAI was 1.31/1.10; PVA was 0.77/0.83; T-EQ was 44.78/44.92 D and T-AST was 4.85/3.92 D. The outcome of patients with a preoperative visual acuity of ≤0.1 was significantly worse than the group with the visual acuity of >0.1. This study shows that the long-term results after penetrating keratoplasty for pseudophacic bullous keratopathy and Fuchs endothelial dystrophy are good. Patients with preoperative visual acuity of ≤0.1 had worse final results.

Corneal topographic changes after transconjunctival 23-gauge sutureless vitrectomy

To evaluate the topographic changes of cornea after pars plana vitrectomy (PPV) with the 23-gauge- (23-G) transconjunctival sutureless vitrectomy (TSV) system within the first postoperative month. In this prospective study, corneal topographic changes were evaluated in 24 eyes of 24 patients who underwent PPV with the 23-G TSV system. All eyes underwent computer-assisted videokeratography using NAVIS (Nidek Advanced Vision Information System) software preoperatively and at the first day, first week, and first month postoperatively. The topographic parameters that were analyzed statistically were the average corneal power (ACP), corneal surface cylinder (CSC), surface asymmetry index (SAI), and surface regularity index (SRI). Mean induced astigmatism was estimated by vector analysis software. The Wilcoxon test was used for statistical analysis. Mean ACP was 43.12±1.16 diopters (D) preoperatively and 42.88±1.44 D at first day (P=0.301), 43.04±1.14 D at first week (P=0.796), and 43.32±1.17 D at first month postoperatively (P=0.187). Mean CSC was 0.61±0.32 D preoperatively and 0.71±0.48 D at first day (P=0.918), 0.60±0.25 D at first week (P=0.826), and 0.70±0.33 D at first month postoperatively (P=0.414). Mean SAI was 0.12±0.05 preoperatively and 0.21±0.16 at first day (P=0.070), 0.15±0.06 at first week (P=0.176), and 0.16±0.09 at first month postoperatively (P=0.198). Mean SRI was 0.41±0.37 preoperatively and 1.05±0.41 at first day (P=0.001), 0.54±0.42 at first week (P=0.211), and 0.41±0.5 at first month postoperatively (P=0.861). Mean surgically induced astigmatism was 0.67±0.7 D at first day, 0.36±0.2 D at first week, and 0.33±0.17 D at first month postoperatively. Corneal surface and astigmatic changes were observed to be insignificant in the early postoperative period after PPV with the 23-G TSV system.

Quantitative evaluation of night vision and correlation of refractive and topographical parameters with glare after orthokeratology

To evaluate night vision disturbance and investigate correlations between pre- and post-treatment parameters and glare scores in orthokeratology patients. Twenty-eight right eyes of 28 patients were enrolled in this study. Corneal topography and a night vision test (NVT) to evaluate the extent of glare were performed after orthokeratology. From the corneal topography, two indices [surface regularity index (SRI) and surface asymmetry index (SAI)] were calculated. Fourier analysis was performed on the topographic data from the central 6mm, and data were decomposed into asymmetric and higher order components for analysis. There was no correlation between the glare score and pre-treatment keratometric value, pre-treatment cylinder, post-treatment sphere, and post-treatment cylinder. However, there was a statistically significant correlation between pre-treatment sphere and glare score (Pearson correlation coefficient, r = -0.54, p < 0.01). SRI and SAI significantly correlated with glare score (SRI: r = 0.52, p < 0.01, SAI: r = 0.41, p < 0.05). Higher order and asymmetric components were also significantly correlated with glare score (asymmetry: r = 0.61, p < 0.01, higher order: r = 0.67, p < 0.001). The glare score was significantly correlated with corneal irregularity, and appeared to be a beneficial parameter for assessment of night vision performance in patients receiving orthokeratology.

Surface quality of human corneal lenticules after femtosecond laser surgery for myopia comparing different laser parameters

To determine the surface characteristics of human corneal lenticules after femtosecond laser surgery for myopia. The Carl Zeiss Meditec AG VisuMax® femtosecond laser system was used for refractive correction called Femtosecond Lenticule Extraction on 24 myopic eyes. The surface regularity on the refractive corneal lenticules recovered was evaluated by assessing scanning electron microscopy images using an established scoring system. Three different energy levels 150, 180, and 195 nJ were compared (n = 8 in each group). Surface irregularities were caused by tissue bridges, cavitation bubbles, or scratches. The surface regularity index (R(2) = 0.74) decreased as pulse energy increased. The average surface regularity score obtained was 7.5 for 150 nJ, 7.25 for 180 nJ, and 6.25 for 195 nJ. The human corneal lenticules created with the VisuMax® femtosecond laser system are of predictable, good-quality surface. This study shows the influence of pulse energy on surface regularity in human eyes. Further studies should focus on optimization of laser parameters as well as surgical technique to improve the regularity of the corneal stromal bed and so make the advantages of the femtosecond laser technology over conventional techniques clearer in the future.

Kinetic analysis of topographical parameters and interference pattern of tear lipid layer in normal subjects

To investigate the post-blink changes of the topographical regularity indices, the corneal wavefront aberrations and the tear lipid layer's interference pattern, and analyze the relationship between these parameters' changes. Sequential topographical measurements were recorded on 23 normal participants. The surface regularity index (SRI), surface asymmetry index (SAI), corneal total higher order aberrations (HOA) root mean square (RMS), Coma RMS and Spherical RMS were calculated from the topographical measurement. The incidence of the type 1 (with an initial decrease after blink) alteration trend, and the times to the initial minimum were determined in every parameter. The movement of the tear lipid layer's interference pattern was recorded, and the spreading time of the lipid layer was measured subjectively by three independent observers. The incidence of the type 1 SRI trend (82%) was the most common among those measured. The average time to the type 1 SRI trends' minimum was 4.05 ± 1.46 s. There was no correlation between the time to the minimum of type 1 trends of the topographical indices, the HOA, Coma and Spherical RMS. The mean lipid layer spreading time was 5.09 ± 1.90 s. We found weak but significant correlation between the times to the minimum of type 1 SRI trends and the lipid spreading time (r = 0.540, p = 0.021).The minimum of the SRI index occurred before the stoppage of superficial lipid layer's motion. Relatively long lipid layer spreading time was observed suggesting that the tear film build-up process did not finish completely at the end of the initial rapid tear film alteration phase. The detected initial decrease of the SRI after blink related to the post-blink tear film motion. This initial pattern is characteristic of the majority of the normal population in spite of the post-blink alteration pattern of the topographical SAI or corneal aberrations. The SRI seems to be the most useful indirect topographical parameter of the tear film dynamics.

Langzeitverlauf nach perforierender Keratoplastik bei Keratokonus – Auswirkungen von präoperativem Visus und Astigmatismus auf die funktionellen Ergebnisse

The purpose of this study was to assess the long-term functional visual results of penetrating keratoplasty for keratoconus and to assess the impact of the patient's preoperative corneal curvature and preoperative best spectacle corrected visual acuity (BCVA) on the refractive outcome. In this retrospective study 456 patients with keratoconus who received central round penetrating keratoplasty (PK) were examined 1/3/5/8/ > 9 years postoperatively. Patients were divided retrospectively into subgroups: first based on their preoperative keratometric (K-) readings: group I.1, < 50 diopters (D) (n = 21); group I.2, 50 - 60 D (n = 102); group I.3, > or = 60 D (n = 164); group I.4, irregular corneal shape with non-measurable K-reading (n = 158), group I.0 unknown preoperative K-reading (n = 58) and then based on the preoperative BCVA: group II.0 BCVA < or = 0.1 (n = 204); group II.1 BCVA > 0.1 (n = 263). The trephination was performed using the 193-nm excimer laser and the transplanted cornea was fixed by a double running cross-stitch suture. The outcome measures included keratometric central refractive equivalent (KEQ), keratometric astigmatism (AST), spherical equivalent (SEQ), refractive cylinder (CYL), best corrected visual acuity (BCVA), surface regularity index (SRI), surface asymmetry index (SAI)topographic central power equivalent (T-EQ) and topographic astigmatism (T-AST). Five/eight years postoperatively, BCVA was 0.71/0.73; KEQ was 43.4/44.4 D; SEQ -1.6/-0.8; AST was 3.4/3.6 D; CYL was 3.0/3.0 D, SRI was 0.88/0.83; SAI was 0.78 / 0.78; T-EQ was 44.5/44.9 D and T-AST was 4.0/4.2 D. The results for BCVA of patients whose preoperative BCVA measured < or = 0.1 were significantly worse than the results of patients with better preoperative BCVA. Other comparisons among the subgroups revealed no further significant differences for any parameter tested. In our study the long-term results of BCVA after penetrating keratoplasty for keratoconus seem to be quite stable (0.7). This indicates that corneal transplantation is a viable option in the clinical course of keratoconus. Furthermore, the outcome of PK for keratoconus seems to be independent of the patient's preoperative corneal curvature. In contrast, unfavourable BCVA preoperatively may be a negative predictor for the visual outcome.

Pterjiyum Cerrahisinin Korneal Topografi Üzerine Etkileri

Objective: To evaluate the quantitative and qualitative effects of pterygium surgery on corneal topography. Material and Methods: Eighteen eyes of 17 patients with pterygium were included in the study. Computerized corneal topography were performed preoperatively, at one week-and one month-postoperatively. The quantitative parameters reviewed included central corneal power (sim K), corneal cylinder, surface regularity index (SRI), surface asymmetry index (SAI), horizontal length of the pterygium, surgically induced astigmatism (SIA), and positive astigmatic axis. Topography maps were also evaluated qualitatively. Results: The mean preoperative Sim K was statistically less than the mean Sim K at one week- (p= 0.014) and one month- postoperatively (p= 0.016). The mean SAI at one week-postoperatively was statistically higher than it was at one month-postoperatively (p= 0.017). The mean SRI at one week- postoperatively was higher than it was at one month- postoperatively (p= 0.006). Although there was a tendency towards decrease in corneal cylinder after surgery, this decrease was not statistically significant (p= 0.833). The horizontal length of the pterygium was positively correlated with the preoperative corneal cylinder, SIA at one week-, and SIA at one month- postoperatively (r= 0.741 p= 0.000; r= 0.771 p= 0.000, r= 0.669 p= 0.002, respectively). Preoperative corneal cylinder was positively correlated with SIA at one week- and one month- postoperatively (r= 0.937 p= 0.000, r= 0.966 p= 0.000, respectively). Corneal topography most frequently revealed regular astigmatic patterns before and after surgery. The distribution of spherical, regular astigmatic and irregular astigmatic patterns did not change by surgery (p= 0.949). Conclusion: Pterygium causes reversible changes on corneal topography in accordance with its horizontal length.

A contrastive research on high and normal corneal refractive power with myopia

Objective To study high and normal corneal refractive power comparatively accompanied with myopia, and discuss the surgery selection and safety of eximer corneal refractive surgery. Methods 65 eyes of 34 cases （male 15 cases, 28 eyes; female 19 cases, 37 eyes） which high corneal refractive power was more than or equal to 46D, 68 eyes of 34 cases （male 15 cases, 30 eyes; female 19 cases, 38 eyes） which normal corneal refractive power was less than 46D with no keratoconus were measured by topography. The corneal topography, the corneal curvature, the dioptre （ D）, corneal astigmism, central corneal thickness （CCT） and intraocular pressure （IOP） was analyzed statistically in two groups. Results The mean corneal curvature（ Simk 1 ） was （46.86 -48.99） D in high group and （41.35 -45.75）D in normal one. The age was no significant different between the two groups （ P 〉 0.05 ）. The corneal power of female patients was higher than that of male one in high group （P 〈0.01 ）, but it was no significant different in normal group （ P 〉 0.05 ）. There was significant difference between high group and normal group in CCT, IOP, maximum meridian （ Simk 1 ）, the vertical meridian （ Simk 2 ） , the minimum meridian （Mink） and the difference between simkl and simk2 （Ak）, the surface regularity index （SRI） （P 〈 0.01 ）. There was on significantdifference between high group and normal group in the dioptre（D） , and surface asymmetty index （SAI） （P 〉 0. 05 ）. Conclusion The CCT and lOP in high cornea refractive power eases are less than the normal value. But the Simk 1, Simk 2, Mink, △k, SR] are more than that in the normal group. Key words: corneal refractive power ; myopia ; corneal topography

Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) Using Corneal Donor Tissue Not Acceptable for Use in Penetrating Keratoplasty as a Result of Anterior Stromal Scars, Pterygia, and Previous Corneal Refractive Surgical Procedures

The purpose of this study was to evaluate outcomes of Descemet's stripping automated endothelial keratoplasty (DSAEK) using anterior stromal flawed (ASF) donor corneas that were unsuitable for use in full-thickness penetrating keratoplasty as a result of stromal scars, pterygia, or previous corneal refractive surgery and to compare results with DSAEK using standard tissue. We conducted a review of our initial 42 (19 with 6-month follow up) consecutive DSAEK surgeries using ASF tissue compared with 357 (199 with 6-month follow up) time-matched controls using standard tissue. Intraoperative and perioperative complications, including dislocations and primary graft failures, were compared. Six-month best spectacle-corrected vision, incidence of rejection episodes, postoperative refractive astigmatism, keratometric values, pre- and postoperative topography-derived surface asymmetry index, and surface regularity index were compared. One surgeon-cut ASF tissue was perforated before surgery and was discarded. No surgeon-cut standard tissue was perforated. No intraoperative complications and no episodes of primary graft failure or pupillary block glaucoma occurred in either group. One (2.4%) postoperative graft dislocation and one (5.2%) graft rejection episode occurred in the study group. There were 10 (2.8%) dislocations and 8 (2.2%) graft rejection in the controls. A statistically similar significant improvement in best spectacle-corrected vision occurred in both groups. Corneal topography, pachymetry, and manifest astigmatism were not significantly different between groups. Postoperative results of DSAEK using donor tissue excluded from use in penetrating keratoplasty as a result of stromal flaws are equivalent to results using standard donor tissue. Central corneal thickness measurements should be performed before cutting to avoid tissue perforation. The use of ASF tissue for DSAEK will expand the cornea donor pool.

Comparative Analysis of Some Modal Reconstruction Methods of the Shape of the Cornea from Corneal Elevation Data

A comparative study of the ability of some modal schemes to reproduce corneal shapes of varying complexity was performed, by using both standard radial polynomials and radial basis functions (RBFs). The hypothesis was that the correct approach in the case of highly irregular corneas should combine several bases. Standard approaches of reconstruction by Zernike and other types of radial polynomials were compared with the discrete least-squares fit (LSF) by the RBF in three theoretical surfaces, synthetically generated by computer algorithms in the absence of measurement noise. For the reconstruction by polynomials, the maximal radial order 6 was chosen, which corresponds to the first 28 Zernike polynomials or the first 49 Bhatia-Wolf polynomials. The fit with the RBF was performed by using a regular grid of centers. The quality of fit was assessed by computing for each surface the mean square errors (MSEs) of the reconstruction by LSF, measured at the same nodes where the heights were collected. Another criterion of the fit quality used was the accuracy in recovery of the Zernike coefficients, especially in the case of incomplete data. The Zernike (and especially, the Bhatia-Wolf) polynomials constitute a reliable reconstruction method of a nonseverely aberrated surface with a small surface regularity index (SRI). However, they fail to capture small deformations of the anterior surface of a synthetic cornea. The most promising approach is a combined one that balances the robustness of the Zernike fit with the localization of the RBF.

Corneal Epithelial Opacity in Dysfunctional Tear Syndrome

To compare the appearance of the superficial corneal epithelium in patients with dysfunctional tear syndrome (DTS) and that of an asymptomatic control group using laser scanning confocal microscopy and to determine the correlations between confocal microscopic findings and clinical severity parameters. Prospective case-control study. Thirty-one patients with newly diagnosed DTS and 21 asymptomatic control subjects were evaluated for this study. Subjects with DTS were classified into 4 levels of clinical severity (DTS 1 through 4) based on the Delphi dry eye panel report criteria. The Heidelberg Retina Tomograph 2 Rostock Cornea Module (Heidelberg Engineering GmbH, Heidelberg, Germany) laser scanning confocal microscope was used to image the superficial corneal epithelium. Areas of single or multiple opaque superficial epithelial cells were measured as a percentage of the 400 x 400-microm(2) field area in 4 randomly selected confocal images from each eye. Spearman correlations between the confocal findings and severity of symptoms, visual acuity, and ocular surface signs were calculated. The mean area of opaque superficial corneal epithelial cells was significantly greater in DTS patients than in normal subjects (P < .0001). Significant differences were observed between the DTS severity groups and the control group (P < .001), except for the DTS 1 group. The area of opaque cells significantly increased with level of clinical severity. The confocal findings showed significant correlation with clinical severity parameters, including blurred vision symptoms (r = 0.86; P = .0001), best-corrected visual acuity (Spearman r = 0.4; P = .03), conjunctival lissamine green staining scores (Spearman r = 0.4; P = .026), corneal fluorescein staining scores (Spearman r = 0.5; P = .002), and videokeratoscopic surface regularity index (Spearman r = 0.5; P = .02). Morphologic changes in the superficial corneal epithelium of DTS patients detected by laser scanning confocal microscopy correlates with blurred vision symptoms and objective severity parameters. Objective confocal image analysis of the superficial corneal epithelium may prove useful for classifying DTS severity and for monitoring the efficacy of therapies.

Effect of Chalazion Excision on Refractive Error and Corneal Topography

To evaluate refractive and corneal topographic changes following excision of chalazia. This prospective noncomparative quasi-experimental clinical trial includes consecutive patients older than 7 years with chalazia of minimum duration of 1 month who underwent excision of the lesions by an internal or external approach. Overall, 253 lids from 228 eyes of 195 patients including 110 female subjects with mean age of 31-/+14 years (range 7-71) were studied. Mean duration of presenting symptoms was 4-/+2.8 months (range 1-24). Lesions were equally distributed in medial, central, and lateral areas of the eyelids. The chalazia were single in 172 (88.2%) and multiple in 23 (11.8%) patients. Mean change in best-corrected visual acuity, spherical equivalent refractive error, and difference of keratometry (corneal astigmatism) were 0.0004-/+0.007 logMAR (p=0.3), -0.06-/+0.6 D (p=0.1), and 0.34-/+0.35 (p<0.0001) after surgery, respectively. Corneal topographic analysis revealed significant changes in surface regularity index (0.13), surface asymmetry index (0.09), and potential visual acuity (0.06-/+0.1 logMAR) after the procedure (p<0.0001 for all comparisons). Single, central, and firm chalazia were compared with multiple, peripheral, and soft lesions; change in difference of keratometry and spherical equivalent were 0.75-/+0.42 D versus 0.22-/+0.15 D (p=0.001) and -0.35-/+0.19 versus -0.11-/+0.30 D (p=0.1), respectively, implying more induced astigmatism with the former type of lesions. Chalazion excision can decrease corneal astigmatism and irregularity, which is more prominent in single, firm, and central upper lid lesions. These findings may have implications in pediatric patients at risk for amblyopia.

Microkeratome-assisted anterior lamellar keratoplasty is effective to remove corneal scars

to present our experience with microkeratome-assisted anterior lamellar keratoplasty using a manual microkeratome. left eye of a 67 year old man was operated with microkeratome-assisted lamellar keratoplasty to remove a central corneal scar of the anterior stroma and to reduce secondary high-degree irregular astigmia caused by pterygium remnant. Videokeratography was performed to record the status of the cornea. postoperative best-corrected visual acuity was superior to preoperative value which was 0.6 with +7.0 spherical and -2.0 cylindrical Diopters before the operation. Uncorrected visual acuity improved from 0.15 to 0.6. The topographical cylinder decreased from 7.98 D to 3.79 D, surface asymmetry index from 2.42 to 1.48, surface regularity index form 3.24 to 1.72. Minimum keratometry reading increased from 38.35 to 41.69. microkeratome-assisted anterior lamellar keratoplasty seems to be safe and effective to remove corneal scars and reduce high degree irregular astigmia, moreover, to improve visual acuity.

Postkeratoplasty Corneal Wavefront Analysis of Selective Suture Removal

To analyze the corneal wavefront higher order aberrations (HOAs) after penetrating keratoplasty and selective suture removal. All patients undergoing penetrating keratoplasty by the same surgeon (R.K.F.) using identical suturing technique were retrospectively identified. Corneal HOAs were calculated at the week 6, week 10, 6-month, and final postoperative visits and compared with simulated corneal astigmatism, surface regularity index, surface asymmetry index, and best-corrected visual acuity. Ninety-two eyes were identified. Total corneal HOAs declined from the week 6 visit to the final visit (week 6: 0.65, final: 0.50, P = 0.041). Final visit linear regression demonstrated correlations of surface asymmetry index and surface regularity index with total corneal HOAs (R = 0.51 and R = 0.45, respectively). No relationship for simulated corneal astigmatism or vision was found with total corneal HOAs (R = 0.003 and 0.30, respectively). Total corneal HOAs are increased in the early postkeratoplasty course, possibly representing the optical consequences of surface irregularity. Because simulated keratometry provides no information in regard to corneal HOAs, measuring HOAs may be indicated in select cases. Total corneal HOAs perhaps provide a clinical representation of irregular astigmatism. The visual significance of these total corneal HOAs was not evident.

Production and Activity of Matrix Metalloproteinase-9 on the Ocular Surface Increase in Dysfunctional Tear Syndrome

To evaluate production and activity of metalloproteinase (MMP)-9 on the ocular surface of patients with dysfunctional tear syndrome (DTS) and determine any correlation between MMP-9 activity and clinical parameters. Forty-six patients with newly diagnosed DTS and 18 control subjects were recruited. Complete ocular surface examinations were performed. Tear MMP-9 activity was assessed with an MMP-9 activity assay in 1 microL of unstimulated tear fluid. Using conjunctival epithelial cells from 19 patients with DTS and 16 controls, levels of MMP-9 and its regulating cytokine mRNA transcripts were evaluated by semiquantitative real-time PCR. Each of four DTS severity-based groups had significantly higher mean MMP-9 activities than did the control group, which was 8.39 +/- 4.70 ng/mL. The DTS4 group had the highest MMP-9 activity (381.24 +/- 142.83 ng/mL), for which the mean was significantly higher than that of other DTS groups. In addition, patients with DTS had significantly higher levels of IL-1beta, IL-6, TNF-alpha, and TGF-beta1 mRNA transcripts in their conjunctival epithelia than did the control subjects. Tear MMP-9 activities showed significant correlation with symptom severity scores, decreased low-contrast visual acuity, fluorescein tear break-up time, corneal and conjunctival fluorescein staining, topographic surface regularity index (SRI), and percentage area of abnormal superficial corneal epithelia by confocal microscopy. Tear MMP-9 activity was significantly higher in patients with DTS. This activity was associated with increased mRNA expression of MMP-9 and its regulating genes and correlated strongly with clinical parameters. MMP-9 appears to be a potentially useful biomarker for diagnosing, classifying, and monitoring DTS.

Visual Performance After Reduced Blinking in Eyes With Soft Contact Lenses or After LASIK

To evaluate visual performance during concentrated visual work in patients wearing soft contact lenses or after LASIK. Thirty-one eyes of 17 patients who had worn soft contact lenses before LASIK were examined by the following tests immediately and 10 seconds after eye opening: 1) functional visual acuity, which is defined as visual acuity measured after prolonged eye opening without blinking; 2) surface regularity index (SRI) and surface asymmetry index (SAI) in corneal topography; and 3) higher order aberration measured with NIDEK OPD-Scan. Results were compared in the same patients before (with soft contact lenses and no eye surgery) and 1 month after LASIK (without soft contact lenses). Functional visual acuity was significantly decreased 10 seconds after eye opening compared with immediately after eye opening, both with soft contact lenses and after LASIK, and decreased to a greater extent with soft contact lenses. The SRI and SAI were significantly increased 10 seconds after eye opening compared with immediately after eye opening, both with soft contact lenses and after LASIK, and increased to a greater extent with soft contact lenses. Higher order aberration was increased 10 seconds after eye opening with soft contact lenses, but not after LASIK. Our results suggest that prolonged eye opening induces a decreased quality of vision in eyes of soft contact lens wearers and after LASIK. Under conditions in which blinking is restricted due to concentrated visual work, such as visual display terminal work, reading, and driving, visual performance may be more compromised with soft contact lens wear than after LASIK.

Reversibility of Effects of Orthokeratology on Visual Acuity, Refractive Error, Corneal Topography, and Contrast Sensitivity

To investigate the changes in corneal shape and optical performance during and after discontinuation of overnight orthokeratology for correction of myopia. Both eyes of 15 subjects were fitted with overnight reverse-geometry orthokeratology lenses, which were then worn for >4 hr overnight for 52 weeks. Subjects were free of ocular disease and had a corrected visual acuity of > or =1.0. Refractive correction, uncorrected visual acuity, corneal topography, and contrast sensitivity (at 4 spatial frequencies) were measured under photopic conditions. Refractive error (spherical equivalent) and contrast sensitivity were decreased, whereas uncorrected visual acuity, the surface asymmetry index, and the surface regularity index were increased, 1 week after the onset of overnight orthokeratology and remained so during the 52 weeks of treatment. These parameters had largely returned to baseline values by 8 weeks after treatment discontinuation. Overnight orthokeratology improved uncorrected visual acuity and reduced refractive error but increased corneal irregularity and impaired contrast sensitivity. However, these changes in visual function and corneal shape were reversed after discontinuation of orthokeratology lens wear.

Tear Film Function in Type 2 Diabetic Patients with Retinopathy

Purpose: To investigate whether diabetes mellitus is correlated with tear film dysfunction. Methods: Tear film function tests including tear film breakup time (BUT), fluorescein staining, Schirmer I test, rose Bengal staining, total tear protein detection, tear sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and TMS-4 corneal topography were performed. A dry-eye questionnaire was used. Results: Compared with the control group and nonproliferative diabetic retinopathy (NPDR) group, in the proliferative diabetic retinopathy (PDR) group, the BUT and the value of the Schirmer I test were reduced significantly (p < 0.01); corneal fluorescein staining scores, the positive rate of rose Bengal staining and the surface regularity index (SRI) and surface asymmetry index (SAI) were higher (p < 0.01); concentrations of lactoferrin and tear-specific prealbumin were lower (p < 0.01, p < 0.05, respectively). In diabetic patients, the SRI and SAI were positively correlated with fluorescein staining scores (r = 0.754, 0.480, p < 0.01, respectively), and the dry-eye symptoms were significantly related to an abnormal BUT and Schirmer I test (p < 0.01, respectively). Conclusion: The declined tear film function is severer in the patients with PDR than in those with NPDR. Besides the traditional methods, tear SDS-PAGE and TMS corneal topographic indices contribute to the discovery of tear film dysfunction in diabetic patients.

Descemet-Stripping Automated Endothelial Keratoplasty

To report 6-month results in a large, prospective study of Descemet-stripping automated endothelial keratoplasty (DSAEK). A 5-mm scleral-limbal tunnel approach was created for placement of an automated microkeratome-prepared 8.0-mm endothelial graft after DSAEK in 150 consecutive cases between September 2005 and October 2006. Six-month follow-up data were available on 100 eyes. Intraoperative peripheral scraping was performed to promote adherence of the donor. Preoperative and postoperative visual acuity with and without spectacle correction (BSCVA and UCVA), refractive astigmatism, average topographic keratometry, surface asymmetry index, surface regularity index, and pachymetry were measured prospectively. After DSAEK surgery, average BSCVA improved from 20/86 to 20/38, and average UCVA improved from 20/155 to 20/73, which were both statistically significant (P < 0.05). Excluding 26 eyes with known retinal pathology: 97% of the 74 eyes had a vision of 20/40 or better at 6 months and 14% obtained 20/20 or better. Refractive astigmatism changed an average 0.06 D, and average topographic keratometry changed an average -0.13 D, which were not statistically significant. Surface regularity index and surface asymmetry index improved to normal levels of 0.67 and 1.03, respectively (P < 0.001 and P = 0.002). Pachymetry decreased significantly from 0.70 to 0.66 mm (P = .001). This large prospective study of DSAEK shows that this surgery provides a significant improvement in vision, corneal thickness, and surface regularity. It does not change refractive astigmatism or average topographic keratometry significantly. This newer technique of endothelial keratoplasty yields many of the benefits of its predecessors, deep lamellar endothelial keratoplasty and posterior lamellar keratoplasty, while improving the visual results.