Association Between Corneal Changes and Retinal Oximetry in Diabetes Mellitus.

Purpose: Diabetes mellitus (DM) causes different corneal changes that are associated with the severity of diabetic retinopathy. To identify the pathophysiological reasons for this, corneal tomography and optical densitometry (COD) were combined with retinal oximetry. Methods: Patients with DM and healthy subjects were included in this pilot study. Spatially resolved corneal thickness and COD were assessed using the Pentacam HR (Oculus). The pachymetry difference (PACDiff) was calculated as an indicator of an increase in the peripheral corneal thickness. Oxygen saturation (SO2) of the retinal vessels was measured using the Retinal Vessel Analyzer (Imedos Systems UG). Subsequently, the associations between corneal and retinal parameters were analyzed. Results: Data from 30 patients with DM were compared with those from 30 age-matched healthy subjects. In DM, arterial (P = 0.048) and venous (P < 0.001) SO2 levels were increased, and arteriovenous SO2 difference was decreased (P < 0.001). In patients, PACDiff was higher than that in healthy subjects (P < 0.05), indicating a stronger increase in peripheral corneal thickness. The COD was reduced in DM (P = 0.004). The PACDiff of concentric rings with a diameter of 4 mm (r = -0.404; P = 0.033) to 8 mm (r = -0.522; P = 0.004) was inversely correlated with the arteriovenous SO2 difference. Furthermore, PACDiff 4 mm was negatively associated with arterial SO2 (r = -0.389; P = 0.041), and the COD of the peripheral corneal areas correlated positive with arterial SO2 (COD total 10-12 mm: r = 0.408; P = 0.025). Conclusion: These associations might indicate a common pathogenesis of corneal and retinal changes in DM, which could be caused by reduced oxygen supply, mitochondrial dysfunction, oxidative stress, and cytokine effects.

Retinal changes are particularly important for ophthalmologists in the management of diabetes mellitus. These are primarily consequences of diabetic vascular changes that can lead to a lack of oxygen. However, there is also evidence of significant changes in the cornea of patients with diabetes. In the present study, the associations between changes in corneal thickness profile, optical density of the cornea, and oxygen saturation of retinal vessels in diabetes mellitus were demonstrated for the first time. Therefore, this study could contribute to clarifying the possible causes of corneal changes in patients with diabetes.

Evaluation of Corneal Biomechanical Indices in Distinguishing Between Normal, Very Asymmetric, and Bilateral Keratoconic Eyes.

PURPOSE: To evaluate the ability of biomechanical indices provided by the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments) and dynamic Scheimpflug analyzer (Corvis ST; Oculus Optikgeräte GmbH) to distinguish between normal eyes and eyes with very asymmetric ectasia (VAE) and mild and moderate keratoconus. METHODS: This prospective, observational, and monocentric study included normal eyes (defined as keratoconus percentage index < 60, Belin/Ambrósio total deviation value [BAD-D] < 1.6, inferior-superior keratometry [I-S value] < 1.45 and maximum keratometry [Kmax] < 47) and eyes with clinical bilateral keratoconus (mild and moderate) and VAE (defined as unilateral keratoconus, where one eye showed a clinical keratoconus and the fellow eye was topographically normal [VAE-NT] or topographically and tomographically normal [VAE-NTT]). All eyes were measured by the Pentacam (Oculus Optikgeräte GmbH), ORA, and Corvis ST. Receiver operating characteristic curve analysis was performed to test the diagnostic ability. RESULTS: Fifty-eight normal eyes and 238 ectatic eyes were included. The highest area under the curve (AUC) was provided by the Corvis Biomechanical Index (CBI) with an AUC of 0.979, followed by ORA corneal resistance factor (0.865), and corneal hysteresis (0.824) separating normal eyes from all ectatic subgroups. The AUC of the CBI was statistically significantly higher than all other parameters (DeLong test, P < .001). A sensitivity of 100% and 70.9%, respectively, and a specificity of 93.1% was found to distinguish normal eyes from VAE-NT and VAE-NTT using a cut-off value of 0.2. CONCLUSIONS: The assessment of biomechanical properties is an additional important method to evaluate corneal ectasia independent of its stage. The CBI provides further information for ectasia screening in cases where corneal topography and tomography are clinically not suspicious by using a cutoff of 0.2. [J Refract Surg. 2022;38(6):364-372.].

Effect of upper eyelid blepharoplasty on corneal biomechanical, topographic and tomographic parameters 4 weeks after surgery.

PURPOSE: To investigate the effect of "skin-only" upper eyelid blepharoplasty on corneal biomechanics and central as well as peripheral topographic/tomographic parameters before and 4 weeks after surgery. METHODS: In a prospective study, the corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated before and after blepharoplasty. Corneal topographic (maximum simulated keratometry value, inferior-superior value, index of surface variance, index of vertical asymmetry, index of height asymmetry, index of height decentration) and tomographic parameters (corneal thickness, corneal astigmatism and mean 5-mm- and 7-mm-zone keratometry value) were measured by the Pentacam HR. Statistical analysis was performed using a linear mixed model considering correlated data of both eyes. RESULTS: This study included 42 eyes of 35 patients (mean age: 64.5 years, range 52-82 years). Four weeks after surgery CH and CRF increased (9.4 ± 2.3 to 10.2 ± 2.2 mmHg and 9.7 ± 2.1 to 10.5 ± 2.2 mmHg) but did not reach statistical significance (P = 0.100 and P = 0.072). A significant increase in central maximum simulated keratometry value (Kmax) from 45.0 ± 2.3 to 45.4 ± 2.2 diopters (D) was observed (P = 0.004). Inferior-superior value (I-S) and index of surface variance (ISV) showed significant changes from 0.32 ± 0.98 to 0.10 ± 0.98 D (P = 0.02) and from 19.98 ± 9.84 to 22.93 ± 11.23 (P = 0.009), respectively. These alterations did not affect the subjective spherical equivalent (-0.09 ± 4.71 to -0.04 ± 4.51 D; P = 0.437) and the best-corrected distance visual acuity of patients (0.11 ± 0.14 to 0.15 ± 0.15 logMAR; P = 0.142). Age, gender and corneal thickness were not correlated with pre and postoperative differences of CH, CRF, corneal compensated IOP, Kmax, corneal astigmatism or I-S. CONCLUSION: The trend of increasing CH and CRF values might indicate a rise of corneal damping capacity. Despite statistically significant differences of Kmax, I-S and ISV, all other tomographical and topographical parameters did not change 4 weeks after surgery. The corneal steepening with a mean change of 0.4 diopters and the decrease of I-S with a mean of 0.22 diopters do not seem to have a clinically relevant effect for blepharoplasty patients in daily practice.

The retinal venous pressure at different levels of airway pressure.

PURPOSE: To investigate retinal venous pressure (RVP) as a function of airway pressure (AirP) during the Valsalva maneuver (VM) in human subjects. METHODS: Forty-three healthy volunteers (age, 22.0 (2.3) years) (median and interquartile range) were investigated using the following instruments: dynamic contour tonometer, contact lens dynamometer (CLD), and aneroid manometer. The following measurements were performed in their left eyes: tonometry and dynamometry during VM at different levels of airway pressure (AirP = 0, 10, 20, 30, and 40 mmHg). RESULTS: The median RVP during spontaneous breathing (AirP = 0) was 19.7 (6.4) (median in mmHg (interquartile range)) and the intraocular pressure (IOP) in mydriasis was 16.3 (3.1) mmHg. Spontaneous pulsation occurred in 58.1% of the subjects. RVP increased nonlinearly. The coefficient of variation of four individual measurements of RVP at each pressure level averaged 8.1 (7.6) %. At different AirP levels of 10, 20, 30, and 40 mmHg, the following RVPs were measured: 29.6 (12.6); 34.2 (12.8); 38.0 (10.5); and 40.3 (11.0), respectively. The rise of RVP (Δ RVP) during VM was significantly higher than that of Δ IOP (p < 0.0001, Wilcoxon test). Δ RVP between 0 and 40 mmHg AirP was 20.6 mmHg and Δ IOP 1.5 mmHg. The steepest slope of the RVP/AirP curve was observed at the first step from 0 to 10 mmHg of AirP (∆ RVP = 9.9 mmHg). CONCLUSION: A nonlinear relationship between RVP and AirP was found during VM. Small rises in AirP increase the RVP and affect retinal circulation.

Is the Corneal Thickness Profile Altered in Diabetes Mellitus?

Purpose: To investigate the influence of chronic hyperglycemia in diabetes mellitus (DM) on spatial corneal thickness distribution and to analyze the influence of disease-specific factors. Methods: DM patients and healthy subjects were matched according to age and intraocular pressure (IOP). In diabetics, disease duration, DM type, and HbA1c value were assessed. Spatially resolved corneal thickness was measured by Pentacam HR. Thinnest corneal thickness (TCT) and peripheral pachymetry of concentric circles around TCT were determined. The Dynamic Scheimpflug Analyzer Corvis ST (CST) was used to measure the parameter pachy slope, which is an indicator of the change of corneal thickness from the apex to the periphery. Results: 59 DM patients and 57 healthy subjects were included. Age (P = .486) and IOP (P = .154) were not different between the groups. In DM, pachy slope was significantly higher than in healthy subjects (41.1 ± 9.87 vs. 35.18 ± 10.64 µm, P = .004). Also, the differences between TCT and the average of peripheral corneal thickness of concentric circles with a diameter of 2 mm (10.3 ± 1.7 vs. 9.3 ± 3.8 µm, P < .001) to 6 mm (82.2 ± 12.4 vs. 76.8 ± 12.6 µm, P = .011) were increased in patients. Changes in thickness profile were associated with HbA1c value and presence of diabetic retinopathy or maculopathy. Conclusion: In DM, a stronger peripheral corneal thickness increase was detectable. This change was shown using the novel CST parameter pachy slope and confirmed by Pentacam readings. These alterations might affect IOP and biomechanical measurements, and influence refractive procedures.

Corneal Densitometry in Diabetes Mellitus.

PURPOSE: Chronic hyperglycemia induces morphological and functional changes of the cornea. Corneal clarity is essential for visual function, and the measurement of corneal optical density (COD) might provide further information on diabetes mellitus (DM)-induced alterations. METHODS: COD of patients with DM and age-matched healthy subjects was measured using the Pentacam HR. Furthermore, central and thinnest corneal thickness and peripheral pachymetry of concentric circles around thinnest corneal thickness were investigated. In DM, information on disease duration, type, presence of diabetic retinopathy and maculopathy, and HbA1c value was recorded. RESULTS: In this study, 76 patients with DM and 65 healthy subjects were included. In patients with DM, the COD values of nearly all corneal layers and zones were reduced in comparison with healthy subjects (P < 0.05). Furthermore, the COD measurements were inversely correlated with the HbA1c value (total COD central layer: r = -0.424, P = 0.044) and stage of diabetic retinopathy (total COD: r = -0.271, P = 0.019). Diabetic patients with maculopathy revealed lower total COD values than patients without maculopathy (16.5 ± 5.6 vs. 21 ± 7.6, P = 0.031), and COD was lower in DM type 1 than in type 2 (16.1 ± 5.1 vs. 20.8 vs. 7.5, P = 0.035). In both groups, the COD values increased with age (patients with DM: r = 0.336, P = 0.003; healthy subjects: r = 0.679, P < 0.001) and decreased with peripheral corneal thickness increase. CONCLUSIONS: In patients with DM, COD was significantly reduced in comparison with healthy subjects. These changes were associated to disease-specific factors and measurements of peripheral corneal thickness profiles.

Factors Influencing Corneal Biomechanics in Diabetes Mellitus.

PURPOSE: Diabetes mellitus (DM) induces changes in corneal biomechanical properties. The influence of disease-specific factors was evaluated, and a novel DM index was created. METHODS: Eighty-one patients with DM and 75 healthy subjects were matched according to age, intraocular pressure, and central corneal thickness. Information on the disease was collected, and measurements with the Ocular Response Analyzer and the Corvis ST were taken. Results were compared between the groups, and the influence of disease-specific factors was evaluated. From dynamic corneal response parameters, a DM index was calculated. RESULTS: In DM, corneal hysteresis was higher than in healthy subjects (10.5 ± 1.9 vs. 9.7 ± 1.9 mm Hg, P = 0.008). In addition, dynamic corneal response parameters showed significant differences. Among others, highest concavity (HC) (17.212 ± 0.444 vs. 16.632 ± 0.794 ms, P < 0.001) and A2 time (21.85 ± 0.459 vs. 21.674 ± 0.447 ms, P = 0.017) as well as A1 (0.108 ± 0.008 vs. 0.104 ± 0.011 mm, P = 0.019) and A2 deflection amplitudes (0.127 ± 0.014 vs. 0.119 ± 0.014 mm, P < 0.001) were increased in DM. In DM type 1, HC deformation amplitude (1.14 ± 0.19 vs. 1.095 ± 0.114 mm, P = 0.035) was higher than in type 2. The time of deflection amplitude max correlated with the severity of retinopathy (R = 0.254, P= 0.023). In case of diabetic maculopathy, A1 velocity (0.155 ± 0.018 vs. 0.144 ± 0.019 ms, P = 0.043) and A2 time (22.052 ± 0.395 vs. 21.79 ± 0.46 ms, P = 0.04) were increased. Deformation amplitude max (R = 0.297, P = 0.024), HC time (R = 0.26, P = 0.049), HC deformation amplitude (R = 0.297, P = 0.024), and A2 deformation amplitude (R = 0.276, P = 0.036) were associated to disease duration. The DM index revealed a sensitivity of 0.773 and a specificity of 0.808 (area under the curve of receiver operating characteristic = 0.833). CONCLUSIONS: In DM, changes in corneal biomechanics were correlated with disease-specific factors. The DM index achieved reliable sensitivity and specificity values.

Clinical and visual outcome of endophthalmitis patients: a single-center experience.

PURPOSE: To report the clinical and visual outcome and the therapeutical management in a large cohort of endophthalmitis patients. METHODS: In a monocentric, observational study, we retrospectively analyzed the data of all patients with endophthalmitis who were referred to the department of ophthalmology of the Carl Gustav Carus Hospital Dresden between 2006 and 2018. RESULTS: In total, data of 104 patients (49 female, 55 male) were included in the present analysis. The most frequent clinical scenario for endophthalmitis was postcataract surgery (30.8%). The most frequent treatment at presentation was a pars plana vitrectomy (ppV) in 42 patients, followed by an intravitreal antibiotic in 41 patients. Out of 41 patients who received an intravitreal antibiotic, 35 patients (85%) needed additional treatment. In contrast, out of 42 patients who received a ppV as the initial treatment, 19 patients (42%) needed additional therapy, which was significantly different (p < 0.0001). The best presenting visual acuity improved significantly after treatment (p < 0.0001). CONCLUSION: The results of the present study suggest that, compared with an intravitreal antibiotic, a ppV as the initial therapy of endophthalmitis might reduce the number of additional treatments. From our data, it can be hypothesized that a ppV should be performed as early as possible to achieve the best visual outcome in most endophthalmitis patients. Prospective studies are now needed to address this issue in greater detail and to confirm our findings.

Intraocular pressure measurements in diabetes mellitus.

PURPOSE: To investigate the impact of diabetes mellitus-induced changes on intraocular pressure measurements using Goldmann applanation tonometry, Ocular Response Analyzer, and Corvis ST. METHODS: Measurements were done using Goldmann applanation tonometry, Ocular Response Analyzer, and Corvis ST in 69 diabetic patients. Biomechanical-corrected intraocular pressure values by Ocular Response Analyzer (IOPcc) and Corvis ST (bIOP) were used. In addition, biometry and tomography were performed and information on diabetes mellitus specific factors was collected. Results were compared to an age-matched group of 68 healthy subjects. RESULTS: In diabetes mellitus, Goldmann applanation tonometry intraocular pressure (P = 0.193) and central corneal thickness (P = 0.184) were slightly increased. Also, IOPcc (P = 0.075) and bIOP (P = 0.542) showed no significant group difference. In both groups, IOPcc was higher than Goldmann applanation tonometry intraocular pressure (P = 0.002, P < 0.001), while bIOP was nearly equal to Goldmann applanation tonometry intraocular pressure (P = 0.795, P = 0.323). Central corneal thickness showed a tendency to higher values in poorly controlled than in controlled diabetes mellitus (P = 0.059). Goldmann applanation tonometry intraocular pressure correlated to central corneal thickness, while IOPcc and bIOP were independent from central corneal thickness in both groups. All intraocular pressure values showed significant associations to corneal biomechanical parameters. Only in diabetes mellitus, bIOP was correlated to Pachy slope (P = 0.023). CONCLUSION: In diabetes mellitus, Goldmann applanation tonometry intraocular pressure was slightly, but not significantly, increased, which might be caused by a higher central corneal thickness and changes in corneal biomechanical properties. However, intraocular pressure values measured by Ocular Response Analyzer and Corvis ST were not significantly different between diabetes mellitus patients and healthy subjects. The bIOP showed a higher agreement with Goldmann applanation tonometry than IOPcc and was independent from central corneal thickness.

Intraocular Pressure Measurement Using Ocular Response Analyzer, Dynamic Contour Tonometer, and Scheimpflug Analyzer Corvis ST.

PURPOSE: To compare intraocular pressure (IOP) measurements with Goldmann applanation tonometry (GAT), ocular response analyzer (ORA), dynamic contour tonometer (DCT), and Corvis ST (CST) in healthy subjects. METHODS: In a prospective, observational study, IOP measurements with GAT (GAT-IOPc), ORA (IOPcc), DCT (DCT-IOP), and CST (bIOP) were performed and analyzed in 94 healthy subjects. RESULTS: Mean age of the participants was 45.6 ± 17.2 years (range 18 to 81 years). Mean GAT-IOPc was 12.9 ± 2.4 mmHg, mean DCT-IOP was 16.1 ± 2.6 mmHg, and mean IOPcc was 15.6 ± 3.3 mmHg. DCT-IOP and IOPcc were significantly higher than GAT-IOPc (P < 0.001). Mean bIOP was 13.5 ± 2.4 mmHg that was slightly higher but not significantly different from GAT-IOPc (P=0.146). Correlation analysis of IOP values and central corneal thickness (CCT) revealed a negative correlation between GAT-IOPc and CCT (r = -0.347; P=0.001). However, IOPcc, DCT-IOP, and bIOP showed no significant correlation to CCT. Only bIOP revealed a weak but significant age dependency (r = 0.321, P=0.002). CONCLUSION: All tonometry devices showed a good agreement of biomechanical corrected IOP values with GAT-IOPc. As no influence of CCT on IOPcc, DCT-IOP, and bIOP was detectable, the used correction algorithms appear to be appropriate in these tonometers in the clinical setting. The highest agreement was found between GAT-IOPc and bIOP. However, bIOP weakly correlated with participants' age. Further studies are needed to elucidate the role of bIOP for IOP measurement.

Predictive value of positive temporal artery biopsies in patients with clinically suspected giant cell arteritis considering temporal artery ultrasound findings.

PURPOSE: To investigate the impact of ocular symptom, non-ocular symptom, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and temporal artery ultrasound (TAU) findings on the predictive value of a positive temporal artery biopsy (TAB) in patients with clinically suspected giant cell arteritis (GCA). METHODS: In a retrospective, interventional study, data from 68 patients with clinically suspected GCA who underwent TAB between 2015 and 2017 were analysed. Analysis included five parameters: ocular symptom, non-ocular symptom, ESR, CRP level and TAU findings. Using a contingency table, each parameter was separately analysed for the predictive value of a positive TAB, and a discriminant analysis was applied to check for the predictive value of a positive TAB under consideration of all five parameters and of the three strongest predictive parameters. RESULTS: A positive TAB was significantly associated with a positive TAU in 15 of 15 patients (p < 0.001), an increased ESR in 37 of 53 patients (p < 0.001), an increased CRP level in 35 of 56 patients (p = 0.004) and non-ocular symptoms in 27 of 40 patients (p = 0.01). A positive TAB was not significantly associated with the presence of ocular symptoms (25 of 46 patients, p = 0.988). Using a discriminant analysis, the combined parameters TAU, ESR and CRP were able to predict a positive TAB in 97.3% of all patients. The positive predictive value was 78.3%, and the negative predictive value was 95.4%. CONCLUSION: Temporal artery biopsy to confirm the diagnosis of GCA may not be mandatory in patients who show an elevated ESR and CRP level and a positive TAU.

Assessment of corneal biomechanical parameters in healthy and keratoconic eyes using dynamic bidirectional applanation device and dynamic Scheimpflug analyzer.

PURPOSE: To investigate corneal biomechanical parameters in healthy and keratoconic eyes using the Ocular Response Analyzer dynamic bidirectional applanation device (ORA) and the Corvis ST dynamic Scheimpflug analyzer (CST). SETTING: Department of Ophthalmology, Carl Gustav Carus University Hospital Dresden, Germany. DESIGN: Prospective, monocentric, case-control study. METHODS: Corneal biomechanical parameters were obtained in 60 eyes of 60 healthy participants (Group I) and 60 eyes of 60 keratoconus patients (Group II) with different grades of severity using the ORA and the CST. Participants were matched by age (Group I: 38.3 years ± 12.8 [SD], Group II: 37.3 ± 11.2 years) and intraocular pressure (Group I: 13.7 ± 1.7 mm Hg, Group II: 13.6 ± 1.5 mm Hg). RESULTS: For the ORA, the receiver operating characteristic curve analysis showed an area under the curve (AUC) of 0.950 for the keratoconus score, a sensitivity of 87% and a specificity of 93%. The AUC for the corneal resistant factor and corneal hysteresis was 0.930 and 0.868 with a sensitivity of 87% and a specificity of 87%, and sensitivity of 80% and a specificity of 80%, respectively. For the CST, the corneal biomechanical index showed the highest AUC (0.977) with a sensitivity of 97% and a specificity of 98%. The AUC of integrated radius (0.974; 90% sensitivity, 93% specificity) was followed by maximum inverse radius (0.962; 92% sensitivity, 93% specificity). Most parameters were able to discriminate healthy eyes from different keratoconus stages and early stages of keratoconus from moderate stages. CONCLUSION: Both devices allowed for good differentiation between healthy eyes and keratoconic eyes and between different severity grades of keratoconus. Several parameters of ORA and CST revealed high sensitivity and specificity values for keratoconus detection.

Measurement of Corneal Biomechanical Properties in Diabetes Mellitus Using the Ocular Response Analyzer and the Corvis ST.

PURPOSE: Hyperglycemia in diabetes mellitus (DM) might induce changes in corneal biomechanics. Therefore, biomechanical properties of the cornea were measured using the ocular response analyzer and the Corvis ST. METHODS: In the study, 35 eyes of 35 diabetic patients were included. After an ophthalmological examination, measurements with the ocular response analyzer and the Corvis ST were taken. Additionally, biometry and corneal topography were performed and HbA1c values were collected. Results were compared to an age-, pachymetry- and intraocular pressure-matched group of 35 healthy subjects. RESULTS: Mean age (67.6 ± 10.3; 64.1 ± 8.3 years), intraocular pressure (13.4 ± 2.9; 12.8 ± 2.8 mm Hg), and central corneal thickness (556.4 ± 31.7; 548.6 ± 32.9 µm) were not significantly different between the groups (P > 0.05). In DM, the corneal hysteresis (CH) and the corneal resistance factor (CRF) were increased (CH: 10.8 ± 2 vs. 9.4 ± 1.6, P = 0.002; CRF: 10.6 ± 2.1 vs. 9.6 ± 1.5, P = 0.022). Also, most dynamic corneal response parameters showed significant differences. Beside others, A1 and A2 deflection amplitudes were increased (P < 0.001) and highest concavity and A2 time were extended (P < 0.001 and 0.007) in DM. According to current HbA1c value, DM was classified as controlled (≤7%) and poorly controlled (>7%) and significant biomechanical differences were measured between both groups. CONCLUSIONS: In DM, significant changes in corneal biomechanical properties were detectable. In patients, CH and CRF were increased and most dynamic corneal response parameters were different compared to healthy subjects.

The short-term effect of acupuncture on different ocular blood flow parameters in patients with primary open-angle glaucoma: a randomized, clinical study.

INTRODUCTION: To investigate the effect of acupuncture on different ocular blood flow (OBF) parameters in patients with primary open-angle glaucoma (POAG). PATIENTS AND METHODS: In a prospective, randomized study, 56 POAG patients were randomly assigned either to an eye-specific acupuncture (group I, n=28) or to an eye-unspecific acupuncture treatment (group II, n=28). Blood flow parameters were measured before and 10 minutes after treatment. Parapapillary retinal blood flow was determined by the Heidelberg retina flowmeter. Retinal vessel diameters were measured by the dynamic vessel analyzer. Pulsatile ocular blood flow, ocular pulse amplitude, and IOP were investigated by the Langham OBF system. Systemic blood pressure was obtained additionally. RESULTS: Pulsatile ocular blood flow increased significantly after the eye-specific acupuncture treatment from 5.6±4.3 to 6.7±4.9 µL/min (P=0.014). There was no significant change in parapapillary retinal blood flow, retinal vessel diameter, systemic blood pressure, or IOP after treatment in neither of the two groups. CONCLUSION: An eye-specific acupuncture treatment may affect OBF in POAG patients.

Rapid progressive visual decline and visual field defects in two patients with the Heidenhain variant of Creutzfeld-Jakob disease.

BACKGROUND: Heidenhain variant of Creutzfeldt-Jakob (HvCJD) is a rare disease, patients presenting with loss of visual acuity and a decline in visual fields. CASE PRESENTATION: Two patients with rapid loss of visual acuity and declining visual fields presented with homonymic hemianopsia over several weeks. Cranial MRI showed neither stroke nor other morphological changes explaining the severe visual field defects. Neurological examination revealed no pathologies. However, lumbar puncture showed an increase in total protein in cerebrospinal fluid (CSF). Visual field testing revealed further deterioration during follow-up. Several weeks later, patients' behaviour changed markedly, exhibiting aggression, declining memory function and physical degeneration. The suspected diagnosis was the Heidenhain variant of Creutzfeld-Jakob disease (HvCJD). CSF analysis showed evidence of PrPSc and 14-3-3 protein. Both patients died within 8 weeks of the CJD diagnosis. CONCLUSIONS: Loss of visual acuity and a decline in visual fields without corresponding MRI findings and marked changes in behaviour should lead to a diagnosis of HvCJD. Corresponding diagnostic tests should be performed for confirmation. The prognosis for survival is poor and should be immediately communicated to affected patients and their relatives.

Measurement of Orbital Biomechanical Properties in Patients with Thyroid Orbitopathy Using the Dynamic Scheimpflug Analyzer (Corvis ST).

PURPOSE: To investigate orbital biomechanical properties in patients with thyroid orbitopathy and in age- and gender-matched healthy subjects using the Corvis-ST (CST, Oculus Wetzlar, Germany). METHODS: The CST allows a non-contact tonometry with an ultra-high-speed Scheimpflug device to record the deformation of the cornea during an air pulse. Biomechanical response parameters (intraocular pressure (IOP), whole eye movement length (WEMl) and time (WEMt), deflection amplitude 2 mm ratio max, deflection amplitude max, stiffness parameter, and biomechanically corrected IOP were measured in 39 patients with thyroid orbitopathy (= group I) and in 33 age- and gender-matched healthy subjects (= group II) using the CST. RESULTS: Mean age in group I was 54.3 ± 11.6 years and in group II 54.2 ± 12.3 years with no statistical significant difference between the groups (P = 0.98). The gender distribution between the groups was not statistically significantly different (P = 0.51). Mean central corneal thickness was 571 ± 30 µm in group I and 563 ± 36 µm in group II (P = 0.306). There were statistically significant differences (P < 0.001) between groups I and II in mean IOP (19.3 ± 4.5 vs. 14.8 ± 2.3 mmHg, mean biomechanically corrected IOP (17.1 ± 3.4 vs. 13.4 ± 2.1 mmHg), mean WEMl (207 ± 57 vs. 322 ± 50 µm), mean WEMt (20.5 ± 1.0 vs. 21.9 ± 0.7 ms), mean IOP-adjusted WEMl (213 ± 56 vs. 314 ± 62 µm), and in mean stiffness parameter (132.5 ± 29.6 vs. 107.8 ± 23.3 mmHg/mm), respectively. CONCLUSION: Biomechanical parameters as measured by the CST were significantly reduced in patients with thyroid orbitopathy compared to age- and gender-matched healthy subjects, indicating a reduction in orbital compliance in thyroid orbitopathy. The parameters WEMl and WEMt might be a useful diagnostic tool to evaluate the condition of the eyeball within the orbit.

Assessment of Optic Nerve Head Pallor in Primary Open-Angle Glaucoma Patients and Healthy Subjects.

PURPOSE: To investigate optic nerve head (ONH) pallor quantitatively in patients with primary open-angle glaucoma (POAG) and in healthy subjects, and to examine the relationship to mean deviation in perimetry (MD), cup-disk ratio (CDR), and diameters of retinal vessels. METHODS: A total of 89 POAG patients (67.6 ± 11.1 years) and 48 healthy subjects (63.3 ± 14 years) were included. A dual-bandpass transmission filter was introduced in the illumination path of the fundus camera of the Dynamic Vessel Analyzer (Imedos Systems UG) and two monochromatic images at different wavelenghts (548 ± 10 and 610 ± 10 nm) were recorded simultaneously. ONH pallor was defined as the quotient of light reflection in both spectral channels. Pallor values were averaged over four fields which were positioned on the ONH. The mean of these measurements was calculated. In 47 of 89 POAG patients diameters of retinal vessels were determined peripapillary. RESULTS: In POAG, the ONH showed a significantly higher pallor value compared to healthy subjects (82.34 ± 19.28 vs. 62.67 ± 10.41, p < 0.001). ONH pallor was correlated to indicators used to estimate disease severity: MD (r = -0.565, p < 0.001) and CDR (r = 0.561, p < 0.001). The pallor value was associated to diameters of retinal arterioles (r = -0.313, p = 0.032) and venules (r = -0.397, p = 0.006). CONCLUSIONS: Pallor determined by this method was higher in POAG patients than in healthy subjects and increased in patients with advanced disease. ONH pallor might result from a reduced blood perfusion of the ONH or tissue atrophy accompanied by vessel obliteration in POAG. By measuring ONH pallor additional diagnostic information about the vitality of the neuroretinal rim might be gained in glaucoma patients.

Effect of selective laser trabeculoplasty on ocular haemodynamics in primary open-angle glaucoma.

PURPOSE: Selective laser trabeculoplasty (SLT) is known to reduce intraocular pressure (IOP) effectively. The aim of this study, however, was to evaluate the effect of SLT on ocular haemodynamics. METHODS: A total of 69 eyes of 69 patients (age 67.8 ± 9.9 years) with already treated primary open-angle glaucoma who were assigned for SLT for further IOP reduction were consecutively enrolled in this prospective interventional case series. Intraocular pressure, the ocular pulse amplitude (OPA), ocular pulse volume (OPV) and pulsatile ocular blood flow (pOBF) were assessed with the Ocular Blood Flow Analyzer prior to and 3 months after SLT. RESULTS: Intraocular pressure was statistically significantly reduced from 16.0 ± 5.4 mmHg to 12.8 ± 4.0 mmHg (p = 0.001). The OPA did not change (p = 0.783) after IOP reduction following SLT. OPV and pOBF increased statistically significantly. OPV increased from 7.33 ± 3.05 to 8.59 ± 3.35 µl (17.2%; p = 0.001) and pOBF from 17.11 ± 5.42 to 19.74 ± 6.59 µl/s (15.4%; p = 0.002). CONCLUSION: Selective laser trabeculoplasty probably does not induce any pharmacological changes effecting systemic blood pressure or ocular blood flow as topical IOP-lowering medication might do, nor does it change biomechanical properties of the eye as surgery could. Therefore, an increase in ocular blood flow following SLT can only be explained by the reduction in IOP and might be a sign of dysfunctional autoregulation in glaucoma patients.

Corneal Biomechanical Changes After Trabeculectomy and the Impact on Intraocular Pressure Measurement.

PURPOSE: To evaluate corneal biomechanical changes induced by trabeculectomy and their impact on intraocular pressure (IOP) measurements. MATERIALS AND METHODS: In total, 35 eyes of 35 consecutive glaucoma patients undergoing first-time trabeculectomy with mitomycin C were enrolled in this prospective interventional case series. Goldmann applanation tonometry (GAT) IOP, central corneal thickness, axial length, and Ocular Response Analyzer measurements [Goldmann-correlated IOP (IOPg), corneal-compensated IOP (IOPcc), corneal hysteresis (CH), and corneal resistance factor (CRF)] were assessed before and 6 months after uncomplicated trabeculectomy. Linear mixed models were used to compare the parameters before and after surgery. RESULTS: IOP, central corneal thickness, and axial length showed a strong correlation with CH and CRF preoperatively and postoperatively. After adjusting for these influencing factors, CH changed from 7.75±1.46 to 7.62±1.66 mm Hg (P=0.720) and CRF from 8.67±1.18 to 8.52±1.35 mm Hg (P=0.640) after trabeculectomy, but these changes were not statistically significant. IOP decreased statistically significantly with all IOP measurements (P=0.001). IOPcc was statistically significantly higher than GAT (4.82±5.24 mm Hg; P=0.001) and IOPg (2.92±1.74 mm Hg; P=0.001) preoperatively and postoperatively (GAT, 3.29±3.36 mm Hg; P=0.001; IOPg, 3.35±1.81 mm Hg; P=0.001). The difference between IOPcc and GAT (P=0.5) and IOPcc and IOPg (P=0.06) did not change significantly before or after trabeculectomy. CONCLUSIONS: Despite a marked IOP reduction and a possible weakening of the ocular walls after trabeculectomy, corneal structural tissue properties are not altered, and therefore, the accuracy of IOP measurements is not changed postoperatively. It seems likely, however, that Goldmann-correlated IOP measurements are underestimated in glaucoma patients before and after surgery.