Marco Zeppieri

Comparison of ICare tonometer with Goldmann applanation tonometer in glaucoma patients.

PurposeTo compare the intraocular pressure (IOP) readings taken with the new ICare tonometer and with the Goldmann applanation tonometer (GAT) and to evaluate the influence of central corneal thickness (CCT) on the IOP measurements. Patients and MethodsOne eye of 178 consecutive patients with primary open-angle glaucoma underwent ultrasonic CCT measurement, followed by IOP evaluation with the GAT and with the ICare tonometer. The deviation of ICare readings from GAT values, corrected according to the Doughty and Zaman formula, was calculated and correlated to CCT by a linear regression model. The agreement between the 2 devices was assessed by use of the Bland-Altman method. ResultsThe average CCT was 552±39 μm. The mean IOP and the mean corrected IOP with GAT were 19.4±5.4 mm Hg, and 18.5±5.7 mm Hg, respectively. The mean ICare IOP reading was 18.4±5.2 mm Hg. The deviations of ICare readings from corrected GAT values were highly correlated with CCT values (r=0.63, P<0.01). Linear regression analysis showed that a CCT change of 10 μm resulted in an ICare reading deviation of 0.7 mm Hg. The Bland-Altman scatter-plot showed a reasonable agreement between the 2 tonometers. ConclusionsThe ICare tonometer can be useful in a routine clinical setting. The IOP readings are quite in accordance with those obtained by GAT. The measurements seemed to be influenced by CCT variations, and thus pachymetry should always be taken into consideration.

Short-term effect of intravitreal injection of Ranibizumab (Lucentis) on intraocular pressure.

PurposeTo investigate short-term effect on intraocular pressure (IOP) after intravitreal injection of ranibizumab (Lucentis) (IVIL). Materials and MethodsThis prospective study included 1 eye of 54 patients (64±12 y) with wet age-related macular degeneration treated with IVIL. IOP measurements with TonoPen were taken: immediately before and 5 seconds, 5, 10, 15, 30, 60 minutes, and 1 day after IVIL. Axial length (with ultrasound biometry) was assessed in 24 eyes. The analysis included IOP difference at various time points and between phakic and pseudophakic eyes and the relationship between axial length and IOP increases after 5 seconds. ResultsMean IOP were 16.3±3.0 mm Hg (range: 12.0 to 21.3), 44.1±10.6 (22.0 to 59.3), 29.0±9.6 (15.0 to 49.0), 25.8±7.9 (16.0 to 45.0), 23.7±6.6 (15.7 to 39.0), 21.9±5.6 (14.7 to 37.0), 18.8±6.1 (10.0 to 35.0), and 16.1±3.0 (11.0 to 21.0), respectively, for time points immediately before, 5 seconds, 5, 10, 15, 30, 60 minutes, and 1 day after IVIL. Differences between before IVIL and after IVIL IOP were statistically significant after 5 seconds, 5, 10, 15, and 30 minutes (P=0.0001); however, were not significant after 1 hour (P=0.064) and 1 day (P=0.449). Differences between phakic and pseudophakic eyes were not significant (P>0.05). The relationship between shorter axial length and IOP increase after 5 seconds was significant (linear regression analysis; R2=0.28, P=0.007). ConclusionsIVIL causes a considerable short-term transient rise in IOP. The IOP increase after IVIL can be statistically significant at 0 to 30 minutes after injection in both phakic and pseudophakic eyes, and tends to be greater in shorter eyes.

Frequency Doubling Technology Perimetry With the Humphrey Matrix 30-2 Test

PurposeTo assess the Humphrey Matrix 30-2 test in detecting functional glaucomatous damage. Patients and MethodsOne eye in each of 60 healthy individuals, 108 patients with ocular hypertension (OHT), and 150 patients with preperimetric (48) or perimetric (102) high-tension primary open-angle glaucoma (POAG) were considered. Visual fields were assessed by the standard automated perimetry (SAP) Humphrey Field Analyzer 30-2, frequency doubling technology (FDT) N-30, and Humphrey Matrix 30-2 tests. Significantly abnormal points in the pattern deviation probability plot, testing time, sensitivity, specificity, and area under the receiver operating characteristic curve of the FDT tests were evaluated. ResultsFDT revealed a significantly greater percentage of depressed points than did SAP in OHT and preperimetric POAG eyes. The FDT-N-30 test showed a significantly greater percentage of areas with P<5% in the OHT, preperimetric POAG, and early POAG groups. The Matrix-30-2 test provided an area under the receiver operating characteristic curve slightly lower than the FDT-N-30 test in the preperimetric POAG group, and significantly greater in the perimetric POAG group. ConclusionsFDT perimetry appeared more sensitive than SAP in detecting early glaucomatous VF loss. The FDT-N-30 test showed a slightly higher ability to detect early glaucomatous damage in patients at risk for the development of glaucoma, whereas the Matrix-30-2 test provided a more detailed characterization of the glaucomatous VF loss pattern, although it required 30% more time.

Probing glaucoma visual damage by rarebit perimetry

Aim: To compare rarebit perimetry (RBP) with standard achromatic perimetry (SAP) in detecting early glaucomatous functional damage. Methods: 43 patients with ocular hypertension (OH), 39 with early primary open angle glaucoma (POAG), and 41 controls were considered. Visual fields were assessed using the Humphrey field analyser (HFA) 30-2 and RBP tests. Differences among the groups were evaluated using Student-Newman-Keuls and χ2 tests. Correlation between HFA and RBP parameters was assessed using the Pearson’s correlation coefficients and regression analysis. Sensitivity and specificity of RBP in detecting early glaucomatous visual damage were calculated with different algorithms. Results: RBP-mean hit rate (MHR) was respectively 88.6% (SD 4.8%) in controls; 79.1% (10.9%) in the OH group; 64.3% (13.8%) in the POAG group (differences statistically significant). Good correlation in the POAG group was found between HFA-mean deviation and RBP-MHR. Largest AROC (0.95) and optimal sensitivity (97.4%) were obtained when an abnormal RBP test was defined as having (at least 1): MHR <80%; >15 areas with a non-hit rate of >10%; ⩾2 areas with a non-hit rate of >50%; at least one area with a non-hit rate of ⩾70%. Conclusions: The RBP appeared to be a rapid, comfortable, and easily available perimetric test (requiring only a PC device), showing a high sensitivity and specificity in detecting early glaucomatous visual field defects.

Corneal Deformation Parameters Provided by the Corvis-ST Pachy-Tonometer in Healthy Subjects and Glaucoma Patients.

Purpose:To evaluate precision and accuracy of Corvis-ST, a new noncontact tonometer equipped with a high-speed Scheimpflug technology, which measures intraocular pressure (IOP), central corneal thickness (CCT), and corneal deformation parameters (CDPs). Relationships among IOP, CCT, and CDPs were also assessed. Materials and Methods:This prospective, randomized study included 1 eye of 164 subjects (79 controls and 85 glaucoma patients), which underwent IOP measurements taken 3 times with Goldmann applanation tonometry (GAT) and Corvis-ST in random order. Precision was evaluated using intraclass correlation coefficients. Intermethod agreement was assessed using Bland-Altman method. Relationships amongst IOP, CCT and CDPs were evaluated using linear regression analysis. Results:Corvis-ST intraclass correlation coefficients ranged between 0.95 and 0.99 for IOP and CCT; between 0.17 and 0.97 for CDPs. Mean (GAT−Corvis-ST) IOP was 1.4±2.7 mm Hg, which appeared related to IOP and CDPs (P<0.05). CDPs significantly differed between glaucoma patients and controls (P<0.05). GAT and Corvis-ST IOP was related to CCT (P<0.05) and CDPs (P<0.001). Conclusions:Corvis-ST precision was excellent for IOP and CCT; moderate for CDPs. Corvis-ST underestimated GAT IOP, especially at higher IOP and at lower corneal deformability levels. GAT and Corvis-ST IOP increased in thicker and less deformable corneas. Glaucoma patients showed significantly less deformable corneas than controls.

Comparison between laser scanning in vivo confocal microscopy and noncontact specular microscopy in assessing corneal endothelial cell density and central corneal thickness.

Purpose: To compare central corneal thickness (CCT) and endothelial cell density (ECD) with laser scanning confocal microscope Heidelberg Retina Tomograph (HRT) II Rostock Corneal Module and noncontact specular microscope Tomey EM-3000 and to assess intra- and interobserver agreement in normal corneas. Methods: This prospective study included 48 normals (69.6 ± 7.2 years, range: 55-80 years) who underwent CCT and ECD with both Tomey and HRT 3 times by 2 independent observers. Measurement differences between instruments, agreement between devices, and test-retest variability (TRV) were determined. Results: Mean CCTs with Tomey and HRT were 529.4 ± 35.4 and 536 ± 37.6 μm (P = 0.06), respectively; average ECDs with Tomey and HRT were 2473.5 ± 242.2 and 2539.7 ± 338.6 cells per square millimeter (P = 0.04), respectively. The mean of the differences (HRT minus Tomey) was 6.5 ± 17 μm for CCT and 65 ± 135.1 cells per square millimeter for ECD. Differences between instruments were not related to CCT (P = 0.35), whereas significantly increased with increasing ECD (P = 0.0001). Intraexaminer TRV for Tomey and HRT were 3.9 ± 3.7 and 22.2 ± 18.4 μm for CCT and 73 ± 63.4 and 152.2 ± 148.4 cells per square millimeter for ECD, respectively; interexaminer TRV was 4.6 ± 4.2 and 23.8 ± 17.3 μm for CCT and 84.9 ± 72.3 and 159.8 ± 149.8 cells per square millimeter for ECD. Conclusions: HRT II Rostock Corneal Module and the Tomey EM-3000 showed an overall good intermethod agreement. HRT showed a tendency to slightly overestimate CCT measurements, significantly underestimate ECD measurements in eyes with a reduced cell density (<2290 cells per square millimeter), and overestimate ECD in eyes with a high cell density. Both instruments showed low intra- and interobserver TRV for both CCT and ECD measurements, which tended to be less for Tomey.

In vivo analysis of conjunctiva in canaloplasty for glaucoma

Aim To assess the epithelial features of the bulbar conjunctiva using in vivo confocal microscopy in patients with glaucoma undergoing canaloplasty. Methods Thirty consecutive patients with glaucoma were enrolled. Canaloplasty was considered successful if the preoperative intraocular pressure (IOP) was reduced by one-third. The conjunctiva was examined using confocal laser-scanning microscopy 1 week before (baseline) and 12 weeks after surgery. The mean density (MMD, cysts/mm2) and mean area (MMA, μm2) of conjunctival microcysts and IOP were measured. Anterior segment optical coherence tomography was performed to evaluate post-operative trabecular distension and scleral modifications at the surgery site. Results Twelve weeks after surgery, canaloplasty was successful in 23 patients (group 1) but unsuccessful in 7 (group 2). At baseline, IOP was 28.1±2.98 and 28.3±2.81 mm Hg, MMD was 10.61±4.31 and 11.35±5.6 and MMA was 2845.02±411.85 and 2700.56±518.85 in groups 1 and 2, respectively (p>0.05). Twelve weeks after canaloplasty, mean IOP was 13.2±4.48 (p<0.05) and 24.6±3.48 mm Hg in groups 1 and 2, respectively. In group 1, MMD and MMA were 37.86±21.4 and 11997.84±8630.35, respectively, a fourfold increase compared to baseline (p<0.001); no significant differences were found in group 2. Conjunctival bleb was not documented in any case. Conclusions Conjunctival microcysts were evident in all glaucomatous eyes prior to surgery, and tended to increase in density and surface area after successful canaloplasty. These findings indicated enhanced aqueous humour filtration across the sclera and conjunctiva after canaloplasty.

Perceived spatial frequency of sinusoidal gratings.

Purpose. The “frequency-doubling” effect or illusion, in which the apparent spatial frequency of a grating appears to be doubled, is produced when a low spatial frequency sinusoidal grating is counterphase flickered at a high temporal frequency. This study examines changes in apparent spatial frequency of sinusoids of various spatiotemporal content after equating them for detectability. Methods. Detection contrast thresholds were determined for various spatiotemporal gratings. The perceived spatial frequency was then evaluated using stimuli that were four and six times detection threshold. Match ratios were determined for each spatiotemporal combination, whereby the periodicity of a stationary sinusoid was matched with that of a counterphase flickered grating. The same matching task was repeated under different matching task instructions for five randomly chosen spatiotemporal combinations. Results. Match ratios were fractional for many spatiotemporal combinations. Apparent spatial frequency ranged from less than veridical to greater than double depending on observer and spatiotemporal stimulus content. The effect of task instruction on match ratios was very small, yet significant. Conclusions. The appearance of fractional spatial frequency percepts draws into question the notion that frequency-doubling is solely generated by spatially non-linear Y-type magnocellular ganglion cells.

Pulsar perimetry in the diagnosis of early glaucoma.

PURPOSE To assess the ability of Pulsar perimetry (Pulsar) in detecting early glaucomatous visual field (VF) damage in comparison with Frequency Doubling Technology (FDT), Scanning Laser Polarimetry (SLP, GDx VCC), and Heidelberg Retina Tomography (HRT). DESIGN Prospective observational cross-sectional case study. METHODS This multicenter study included: 87 ocular hypertensives (OHT); 67 glaucomatous optic neuropathy (GON) patients; 75 primary open-angle glaucoma (POAG) patients; and 90 normals. All patients underwent standard automated perimetry (SAP) HFA 30-2, Pulsar T30W, FDT N-30, HRT II, and GDx VCC. Area under Receiver Operating Characteristic Curves (AROCs) for discriminating between healthy and glaucomatous eyes and agreement among instruments were determined. RESULTS The best parameters for Pulsar, FDT, HRT, and GDx were, respectively: loss variance square root; no. of areas with P< 5%; Cup-Shape-Measure; and Nerve Fiber Indicator (NFI). In detecting POAG eyes, Pulsar (AROC, 0.90) appeared comparable with FDT (0.89) and significantly better than HRT (0.82) and GDx (0.79). For GON, Pulsar ability (0.74) was higher than GDx (0.69) and lower than FDT (0.80) and HRT (0.83). The agreement among instruments ranged from 0.12 to 0.56. Pulsar test duration was significantly shorter than SAP and FDT (P< .001). CONCLUSIONS Pulsar T30W test is a rapid and easy perimetric method, showing higher sensitivity than SAP in detecting early glaucomatous VF loss. Its diagnostic ability is good for detecting early perimetric POAG eyes and fair for GON eyes. Pulsar performance was comparable with FDT, HRT, and GDx, even if the agreement between instruments was poor to fair.

Human Adipose-Derived Stem Cells for the Treatment of Chemically Burned Rat Cornea: Preliminary Results

Abstract Purpose: Adipose-derived stem cells (ADSC) are multipotent, safe, non-immunogenic and can differentiate into functional keratocytes in situ. The topical use of ADSC derived from human processed lipoaspirate was investigated for treating injured rat cornea. Methods: A total of 19 rats were used. Six animals initially underwent corneal lesion experiments with 0.5 N NaOH (right eye) and 0.2 N (left). The 0.2 NaOH protocol was then used in 13 rats. All 26 eyes of 13 rats eyes received topical azythromycin bid for 3 d and divided into five treatment groups (n = 5 eyes/group), which included: control, stem cells, serum, stem + serum and adipose (raw human lipoaspirate). The four treatment groups received topical treatment three times daily for 3 d. Stem cells were isolated and harvested from human lipoaspirate. Topical eye drops were prepared daily with 1 × 105 cells/treatment. Fluorescein positive defect area and light microscope assessment was performed at 20, 28, 45, 50 and 74 h. Animals were sacrificed at 74 h for histological evaluation. Data were statistically analyzed for differences amongst groups. Results: The stem cell-treated eyes had significantly smaller epithelial defects at each time point compared to control- and adipose-treated eyes (p < 0.05). This group showed slightly better epithelium healing than the serum and combined group, yet not significantly different. Histology showed that stem cell-treated corneas had complete re-epithelization, with less inflammatory cells and limited fibroblast activation structure compared with the control eyes. Conclusions: Our preliminary results show that topical treatment with ADSC seems to improve corneal wound healing.