Béla Csákány

Corneal topography changes after a 15 second pause in blinking

Purpose: To examine the effect of a short pause in blinking on the quantitative topographic parameters of the corneal surface. Setting: Refractive corneal surgery unit of a university eye hospital. Methods: Using a TMS‐1 instrument (Computed Anatomy, Inc.), corneal topographic parameters were measured 5 and 15 seconds after a complete blink in 12 healthy subjects. The main outcome measures were changes in the surface regularity index (SRI) and the surface asymmetry index (SAI). Results: During the pause in blinking, the mean SRI value increased from 0.18 ± 0.19 (SD) to 0.30 ± 0.19 (P < .02) and the SAI from 0.21 ± 0.08 to 0.24 ± 0.10 (P = .079, not statistically significant). There were no significant changes in the values for potential visual acuity, corneal refractive power, or astigmatism. Conclusion: The results indicated a significant change in corneal topography during even a short pause in blinking. In follow‐up studies using corneal topography, all measurements should be done at a fixed time after a complete blink.

Intraocular lens exchange in patients with negative dysphotopsia symptoms

PURPOSE: to evaluate the results of intraocular lens (IOL) exchange in cases of severe negative dysphotopsia and to measure the distance between the iris and the IOL optic using ultrasound biomicroscopy (UBM). SETTING: Szent Rókus Hospital and Eye Clinic, Semmelweis University, Budapest, Hungary. METHODS: Data of patients with major negative dysphotopsia symptoms after phacoemulsification with IOL implantation were reviewed retrospectively. In cases in which IOL exchange was performed to diminish the symptoms, the distance between the iris and the anterior surface of the IOL optic was measured by UBM and compared with that in a group of nonsymptomatic pseudophakic patients (control group). RESULTS: in 3806 cataract procedures, 5 eyes (4 patients) had severe negative dysphotopsia symptoms. Intraocular lens exchange was performed in 3 cases. In 1 case, the secondary IOL was implanted in the reopened capsular bag and the symptoms persisted. In 2 cases, the secondary IOL was implanted in the ciliary sulcus and the symptoms resolved. On UBM, the mean iris–optic distance was 0.45 mm ± 0.07 (SD) in the symptomatic group, 0.59 ± 0.29 mm in the control group (n = 21) (P = .353), and 0.00 mm in the sulcus‐fixated group. CONCLUSIONS: The iris–optic distance was not statistically significantly different between eyes with severe negative dysphotopsia symptoms and nonsymptomatic eyes. However, when IOL exchange reduced the iris–IOL distance, the severe negative dysphotopsia symptoms resolved. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Spontaneous alterations of the corneal topographic pattern.

Purpose: To assess whether the type of corneal topographic pattern is stable during a 1‐minute pause in blinking in healthy subjects. Setting: First Department of Ophthalmology, Semmelweis University, Budapest, Hungary. Methods: Corneal topographic images were recorded 5, 15, 30, and 60 seconds after a complete blink in the right eyes of 36 healthy subjects using the TMS‐1 instrument in a prospective observational study. The topographic pattern of each image was assessed from the color‐coded topographic map and classified into 5 groups (in order of decreasing regularity: round, oval, symmetric bow‐tie, asymmetric bow‐tie, and irregular). Results: During the 60‐second period, a change in the type of topographic pattern was found in 19 subjects (53%), whereas in 17 subjects (47%) the pattern was stable. The alteration of the topographic pattern was statistically significant (P<.001). Conclusions: Immediately after blinking, the ocular surface regularity improves, possibly due to the building up of the tear film. This is followed later by the distortion of the ocular surface, which is the precursor of the tear‐film break up phenomenon. Because of these changes, even in healthy eyes, the optimization and standardization of the postblink time of topographic image capture are very important, especially for planning refractive surgery.

Dynamics of ocular surface topography in healthy subjects

Our topography system is an enhancement of a standard TMS‐1 corneal topograph instrument (Computed Anatomy Inc., New York, NY, USA). Topographic images are captured at a rate of 4 s−1, allowing the recording of a series of 120 images in 30 s after a complete blink. In this prospective preliminary study 15 healthy volunteers were examined. The main outcome measures were the time profile of changes in surface regularity index (SRI), surface asymmetry index (SAI) and simulated keratometry values (K1, K2). After a blink there was a tendency for improvement in ocular surface regularity. Later trends were less clear. Our topography system makes possible the detailed evaluation of tear‐film dynamics in the post‐blink period. The new technique may play an important role in the diagnosis of various tear‐film abnormalities; the results may also have significant implications in the planning of refractive surgeries.

[Ultrasonographic findings in endophthalmitis following cataract surgery : a review of 81 cases].

PURPOSE Review and analysis of ultrasonographic data of patients with endophthalmitis following cataract surgery. PATIENTS AND METHODS We conducted a retrospective analysis of data and ultrasound findings of 81 patients with endophthalmitis following cataract surgery between 2000 and 2005. We evaluated the type of surgery, time of onset of endophthalmitis, and different ultrasonographic findings. RESULTS During the study period, acute endophthalmitis following cataract surgery developed in 41 eyes, subacute endophthalmitis in 25 eyes, and late-developing endophthalmitis in 20 eyes. In 51% of the cases, the endophthalmitis occurred after the phacoemulsification method. Ultrasonographic findings such as membrane formation were found in 23 eyes (28%), and dense vitreous opacities were detected in nine eyes. Posterior wall thickness was measured in 73 eyes. Two initial echography findings were associated with acute and subacute endophthalmitis: dense vitreous opacities and detachment of the posterior vitreous limiting membrane. CONCLUSION Ultrasonographic findings such as increased thickness of the posterior wall and dense organization of the vitreous can be useful in the clinical evaluation, prediction, and treatment of postoperative endophthalmitis.

Reproducibility of keratometric measurements decreases with time after blinking

Purpose The reproducibility of keratometry measurements was investigated in relation to the elapsed time after blinking. Methods Thirty ophthalmologically healthy subjects were examined, using a standard corneal topographic instrument (17 women, 13 men, age 25.7±5.6 years). Photographs were taken in series of four: at 5, 15, 30, and 60 seconds after a complete blink. The series was repeated three times in each individual. The main outcome measures were the mean values, the standard deviation, and the reproducibility error of the simulated keratometric values (K1, K2), the surface regularity index (SRI), and the surface asymmetry index (SAI). Results The mean of K1 and K2 values did not change (p=0.684 and p=0.982); however, the measurement error increased significantly for K1 (p=0.007) and for K2 (p=0.038). The mean values of SRI changed significantly (p=0.034) during the 1-minute pause in blinking together with a non-significant change in the standard deviation (p=0.106), without elevation of the measurement error (p=0.619). The elevation of SAI with time was not significant (p=0.093). Conclusions The break-up phenomenon of the tear film at the ocular surface induces significant deterioration of the reliability of keratometric measurements on prolonged gaze without blinking. The created error can exceed 0.6 D, which is unacceptably high in practice. Therefore care should be taken to avoid such circumstances during the examination.

Tear film function in patients with seasonal allergic conjunctivitis outside the pollen season.

Background: Seasonal allergic conjunctivitis can manifest itself through tear film instability and symptoms of eye discomfort during the pollen season. This study investigated whether seasonal allergic inflammation defines tear film instability outside the season. Methods: Twenty-three control subjects and 13 ragweed-allergic patients were involved (21 female, 15 male; mean age 26.6 ± 5.4 years). Outside the pollen season, subjective ocular symptoms, non-invasive tear film break-up time, lower tear meniscus height and the tear lipid layer’s interference pattern grade were recorded. C3a complement activation level was also measured in collected tear samples. Results: Non-invasive tear film break-up time, lower tear meniscus height, C3a complement activation level and the incidence of the different grades of tear lipid pattern did not differ significantly in the two examined groups (p ≧ 0.223). The mean eye symptom score outside the season was greater in the allergic group, but the difference was not significant (p = 0.062). The C3a complement activation level showed a significant and inverse correlation with the lipid layer grade (r = –0.343, p = 0.017). Among the participants with thinner tear lipid layers, the complement activation in the tear samples was higher than among those patients with normal tear lipid layers. Conclusion: Seasonal allergic inflammation did not cause permanent tear film instability and eye symptoms were not observed outside the pollen season.

Ultrasonographische Befunde bei Endophthalmitis nach Kataraktoperationen

PURPOSE Review and analysis of ultrasonographic data of patients with endophthalmitis following cataract surgery. PATIENTS AND METHODS We conducted a retrospective analysis of data and ultrasound findings of 81 patients with endophthalmitis following cataract surgery between 2000 and 2005. We evaluated the type of surgery, time of onset of endophthalmitis, and different ultrasonographic findings. RESULTS During the study period, acute endophthalmitis following cataract surgery developed in 41 eyes, subacute endophthalmitis in 25 eyes, and late-developing endophthalmitis in 20 eyes. In 51% of the cases, the endophthalmitis occurred after the phacoemulsification method. Ultrasonographic findings such as membrane formation were found in 23 eyes (28%), and dense vitreous opacities were detected in nine eyes. Posterior wall thickness was measured in 73 eyes. Two initial echography findings were associated with acute and subacute endophthalmitis: dense vitreous opacities and detachment of the posterior vitreous limiting membrane. CONCLUSION Ultrasonographic findings such as increased thickness of the posterior wall and dense organization of the vitreous can be useful in the clinical evaluation, prediction, and treatment of postoperative endophthalmitis.

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

Purpose:  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.

Spontaneous calcification of a choroidal melanoma

for ocular diseases and had history of ocular surgery or contact-lens use. Seventeen healthy volunteers (nine male, eight female; 32.8 ± 4.9 years) met these criteria and were enrolled in this study. The lateral eye with more tear secretion was selected for the study. This research was approved by the institutional review board of Ryogoku Eye Clinic and was performed in accordance with the tenets of the Declaration of Helsinki. For the FVA measurement, we selected a 2-second duration for the presentation of optotypes and the patients were allowed to blink freely during the measurements. Topical anaesthesia was not administered. Corneal topography was assessed using the TMS-2N instrument (Tomey Corporation, Nagoya, Japan). Measurements were made immediately after and 5 min after instilling 0.1SH and 0.3SH. Each measurement with different eyedrops was performed on a different day. The eye before using eyedrops served as a control. Two-way analysis of variance (anova) for FVA, Wilcoxon’s signedrank test for the surface asymmetry index (SAI) and surface regularity index (SRI) were used to compare the control and 0.1SH and 0.3SH groups. During the 30 seconds immediately after instilling 0.3SH, the FVA deteriorated significantly compared to the control, whereas the FVA did not change in the control eye or with 0.1SH (Fig. 1A). Five minutes after instillation, no significant differences were observed among all three groups (Fig. 1B). As shown in Table 1, both the SRI and SAI were increased immediately after instilling 0.3SH, but not with 0.1SH. Five minutes after instillation, no significant differences of SRI and SAI were observed among the three groups. SRI and SAI approach zero for a normally smooth corneal surface and increase directly with irregular astigmatism (Wilson & Klyce 1991). The corneal topography findings implicated irregularity in the tear film in this temporary blurring of vision. With the FVA system, we were able to detect the transient, short-term blurring of vision caused by viscous eyedrops.