Kaweh Mansouri

Continuous intraocular pressure monitoring with a wireless ocular telemetry sensor: initial clinical experience in patients with open angle glaucoma

The authors report their initial clinical results with a novel wireless ocular telemetry sensor (OTS) (Sensimed AG, Switzerland) for continuous intraocular pressure (IOP) monitoring in patients with open angle glaucoma. This was a prospective, observational cohort of 15 patients. The OTS is a disposable silicone contact lens with an embedded micro-electromechanical system, which measures changes in corneal curvature induced by variations in IOP. An antenna, mounted around the eye, receives the data, which are then transmitted to a recorder. A signal was recorded in all patients. Thirteen (87%) patients completed 24-h IOP monitoring: one patient discontinued IOP monitoring due to device intolerance, and incomplete recordings were obtained in a second patient due to technical device malfunction. In 9/13 (69%) patients, the highest signals were recorded during the nocturnal period. No serious adverse events were recorded. The OTS shows good safety and functionality to monitor IOP fluctuations in patients over 24 h. This technology has the potential to provide hitherto unobtainable data on the chronobiology of IOP, possibly leading to improved care of glaucoma patients.

The Structure and Function Relationship in Glaucoma: Implications for Detection of Progression and Measurement of Rates of Change

PURPOSE To evaluate the relationship between change in estimated retinal ganglion cell (RGC) counts and change in measures of functional and structural damage in glaucoma, from cross-sectional data. METHODS The study included 397 eyes of 397 patients with glaucoma, suspects, and healthy individuals. All eyes underwent testing with standard automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT). Estimates of retinal ganglion cell (RGC) counts were obtained from SAP and SD-OCT using a previously derived algorithm. Smoothing spline curves were fitted to investigate the relationship between functional/structural parameters and RGC counts. The first derivatives (i.e., slopes) of these curves were obtained to investigate the relationship between changes in these measures. RESULTS A nonlinear relationship was observed between SAP mean deviation (MD) and RGC counts. The same amount of RGC loss corresponded to largely different amounts of MD change depending on the stage of the disease. For SDOCT average retinal nerve fiber layer (RNFL) thickness, a linear relationship was seen with RGC counts throughout most of the spectrum of disease, but reaching a plateau in advanced glaucoma. Changes in RGC counts for eyes with early damage corresponded to small changes in MD, but to relatively larger changes in RNFL thickness. For eyes with advanced disease, changes in RGC counts produced relatively larger changes in MD but only small or no changes in average RNFL thickness. CONCLUSIONS The analysis and interpretation of rates of SAP and SD-OCT change, as indicators of the velocity of neural damage in glaucoma, should take into account the severity of the disease.

Long-term results of deep sclerectomy with collagen implant

Purpose: To study prospectively the success rate and complications of deep sclerectomy with collagen implant (DSCI). Setting: Glaucoma Unit, Department of Ophthalmology, Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland. Methods: This nonrandomized prospective trial comprised 105 eyes of 105 patients with medically uncontrolled primary and secondary open‐angle glaucoma. Visual acuity, intraocular pressure (IOP), and slitlamp examinations were performed before surgery and after surgery at 1 and 7 days, and 1, 3, 6, 9, 12, 18, 24, 30, 36, 48, 54, 60, 66, 72, 78, 84, 90, and 96 months. Visual field examinations were repeated every 6 months. Results: Mean follow‐up period was 64 months ± 26.6 (SD). Mean preoperative IOP was 26.8 ± 7.7 mm Hg, and mean postoperative IOP was 5.2 ± 3.35 mm Hg at day 1 and 12 ± 3 mm Hg at month 78. At 96 months, the qualified success rate (ie, patients who achieved IOP <21 mm Hg with and without medication) was 91%, and the complete success rate (ie, IOP <21 mm Hg without medication) was 57%. At 96 months, 34% of patients had an IOP <21 mm Hg with medication. Fifty‐one patients (49%) achieved an IOP ≤15 mm Hg without medication. Neodymium:YAG goniopuncture was performed in 54 patients (51%); mean time of goniopuncture performance was 21 months, and mean IOP before goniopuncture was 20 mm Hg, dropping to 11 mm Hg after goniopuncture. No shallow or flat anterior chamber, endophthalmitis, or surgery‐induced cataract was observed. However, 26 patients (25%) showed a progression of preexisting senile cataract (mean time 26 months; range 18 to 37 months). Injections of 5‐fluorouracil were administered to 25 patients (23%) who underwent DSCI to salvage encysted blebs. Mean number of medications per patient was reduced from 2.3 ± 0.7 to 0.5 ± 0.7 (signed rank P<.0001). Conclusion: Deep sclerectomy with collagen implant appears to provide stable and reasonable control of IOP at long‐term follow‐up with few immediate postoperative complications.

Assessment of choroidal thickness and volume during the water drinking test by swept-source optical coherence tomography.

OBJECTIVE To evaluate changes in peripapillary and macular choroidal thickness and volume after the water-drinking test (WDT) using swept-source optical coherence tomography (SS OCT). DESIGN Prospective, cross-sectional, observational study. PARTICIPANTS Fifty-six eyes of 28 healthy volunteers. METHODS Participants underwent a 3-dimensional optic disc and macula scanning protocol with a prototype SS OCT (Topcon, Inc., Tokyo, Japan) at baseline and 15, 30, 45, and 120 minutes after the start of the WDT. The WDT consisted of drinking 1000 ml of water within 5 minutes. Objective measurements of the choroid were obtained with automated segmentation of the choroidal boundaries. MAIN OUTCOME MEASURES Choroidal thickness and volume. RESULTS Mean age ± standard deviation of participants was 35.6 ± 9.1 years. Intraocular pressure (IOP) increased from 14.9 ± 2.7 mmHg at baseline to a peak of 16.8 ± 3.0 mmHg 15 minutes after the WDT (P < 0.001). Mean baseline choroidal thickness and volume were 181.3 ± 50.8 μm and 6.19 ± 1.80 mm(3), respectively, at the optic disc and 217.4 ± 43.6 μm and 7.83 ± 1.55 mm(3), respectively, at the macula. After the WDT, peripapillary and macular choroidal thickness increased by a maximum of 5.7% (P<0.001) and 4.3% (P<0.001), respectively. Choroidal volumes increased by 6.4% (P<0.001) and 3.9% (P<0.001), respectively. There was no association between change in IOP and peripapillary (P = 0.27) or macular (P = 0.09) choroidal thickness. CONCLUSIONS Using automated segmentation of SS OCT measurements, significant increases in choroidal thickness and volume are observed after the WDT in healthy subjects.

Assessment of rates of structural change in glaucoma using imaging technologies

PurposeTo review the ability of current imaging technologies to provide estimates of rates of structural change in glaucoma patients.Patients and methodsReview of literature.ResultsImaging technologies, such as confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT), provide quantifiable and reproducible measurements of the optic disc and parapapillary retinal nerve fibre layer (RNFL). Rates of change as quantified by the rim area (RA) (for CSLO) and RNFL thickness (for SLP and OCT) are related to glaucoma progression as detected by conventional methods (eg, visual fields and optic disc photography). Evidence shows that rates of RNFL and RA loss are significantly faster in progressing compared with non-progressing glaucoma patients.ConclusionMeasurements of rates of optic disc and RNFL change are becoming increasingly precise and individualized. Currently available imaging technologies have the ability to detect and quantify progression in glaucoma, and their measurements may be suitable end points in glaucoma clinical trials.

Quality of diurnal intraocular pressure control in primary open-angle patients treated with latanoprost compared with surgically treated glaucoma patients: a prospective trial

Purpose: To compare the intraocular pressure (IOP) diurnal fluctuations of glaucoma patients treated with latanoprost 0.005% once a day with patients with controlled IOP after deep sclerectomy or trabeculectomy. Methods: The trial included 60 prospectively recruited subjects with primary open-angle glaucoma. The medical group consisted of 20 patients with controlled IOP (<18 mm Hg) under latanoprost 0.005% monotherapy and with no history of previous intraocular surgery or argon laser trabeculoplasty; the surgical groups included 20 patients after trabeculectomy, and 20 patients after deep sclerectomy with collagen implant (DSCI). The patients in the surgical groups had a controlled IOP without any ocular hypotensive medications. All patients underwent a diurnal tension curve (08:00–17:00/three-hour intervals), followed by a water-drinking test (WDT) with the last IOP measurement taken at 21:00 hours. The between-group differences were tested for significance by means of analysis of variance (ANOVA). Results: Baseline IOP was significantly different between the trabeculectomy group (10.1 mm Hg (3.4 SD)), the DSCI group (13.9 mm Hg (2.8)) and the latanoprost group (15.5 mm Hg (2.0); p = 0.005). The average IOP during the diurnal tension curve (10.1, 13.7, and 15.7 mm Hg, respectively, for the trabeculectomy, DSCI, and latanoprost groups) differed significantly between groups (ANOVA; p<0.0001), but the variation was comparable in the three groups (ANOVA; p = 0.13). After the WDT, elevation of IOP was significantly greater among patients treated with latanoprost (p = 0.003). Conclusion: Trabeculectomy patients had a statistically significant lower average IOP in the diurnal tension curve compared with the other two groups. No wider variation in diurnal IOP with latanoprost compared with the surgical procedures was found. The IOP increase during the WDT was most marked in patients under latanoprost therapy.

Effects of aging on 24-hour intraocular pressure measurements in sitting and supine body positions.

PURPOSE To evaluate how aging alters 24-hour measurements of intraocular pressure (IOP) in the sitting and supine body positions. METHODS Fifteen older volunteers with healthy eyes (ages, 53-71 years) were each housed for 1 day in a sleep laboratory. An 8-hour accustomed sleep period was assigned to each subject. Every 2 hours, measurements of IOP were taken in the sitting and supine positions. Sitting and supine patterns of 24-hour IOP were compared. Simulated 24-hour IOP rhythms in the same body position were determined using cosine fitting of individual 24-hour data. The average postural IOP effects during the diurnal/wake period and the nocturnal/sleep period were compared. Data from this group of older subjects were compared with previously collected data from 16 healthy younger subjects (ages, 18-25 years) under the same experimental conditions. RESULTS Within each age group, sitting and supine patterns of 24-hour IOP were similar and parallel. Compared to the younger subjects, the phase timing (simulated peak) of 24-hour IOP was significantly delayed for the older subjects in both body positions. The postural IOP effect for the older subjects was 4.7 ± 0.8 and 4.8 ± 0.8 mm Hg during the diurnal and nocturnal periods, respectively. These postural IOP effects were not significantly different from the postural effects in the younger subjects. CONCLUSIONS Although aging can significantly delay the phase timing of the 24-hour IOP pattern toward the diurnal/awake period, it may not affect the postural IOP effect during the diurnal and the nocturnal periods.

Analysis of Continuous 24-Hour Intraocular Pressure Patterns in Glaucoma

PURPOSE To present a method to analyze circadian intraocular pressure (IOP) patterns in glaucoma patients and suspects undergoing repeated continuous 24-hour IOP monitoring. METHODS Forty patients with established (n = 19) or suspected glaucoma (n = 21) underwent ambulatory 24-hour IOP monitoring on two sessions 1 week apart using a contact lens sensor (CLS). The CLS provides its output in arbitrary units (a.u.). A modified cosinor rhythmometry method was adapted to the CLS output to analyze 24-hour IOP patterns and their reproducibility. Nonparametric tests were used to study differences between sessions 1 and 2 (S1 and S2). Patients pursued their routine daily activities and their sleep was uncontrolled. CLS data were used to assess sleep times. RESULTS Complete 24-hour data from both sessions were available for 35 patients. Mean (SD) age of the patients was 55.8 ± 15.5 years. The correlation of the cosinor fitting and measured CLS values was r = 0.38 (Spearman r; P < 0.001) for S1, r = 0.50 (P < 0.001) for S2, whereas the correlation between S1 and S2 cosinor fittings was r = 0.76 (P < 0.001). Repeated nocturnal acrophase was seen in 62.9% of patients; 17.1% of patients had no repeatable acrophase. The average amplitude of the 24-hour curve was 143.6 ± 108.1 a.u. (S1) and 130.8 ± 68.2 a.u. (S2) (P = 0.936). CONCLUSIONS Adapting the cosinor method to CLS data is a useful way for modeling the rhythmic nature of 24-hour IOP patterns and evaluating their reproducibility. Repeatable nocturnal acrophase was seen in 62.9% of patients. (ClinicalTrials.gov number, NCT01319617.).

Association between Corneal Biomechanical Properties and Glaucoma Severity

PURPOSE To investigate the association between corneal biomechanical parameters using the Ocular Response Analyzer (ORA) and glaucoma severity. DESIGN Observational cross-sectional study. METHODS Two hundred ninety-nine eyes of 191 patients with confirmed or suspect glaucoma were recruited at the University of California, San Diego. Corneal hysteresis (CH) and corneal resistance factor (CRF) were obtained from all participants. Standard automated perimetry was done using the 24-2 Swedish Interactive Threshold Algorithm. Retinal nerve fiber layer (RNFL) thickness measurements were obtained using GDx ECC and spectral-domain optical coherence tomography (SD-OCT). The association between ORA parameters and disease severity was evaluated using univariable and multivariable regression models. RESULTS CH and CRF were both positively associated with mean defect (MD) (R(2) = 0.03; P < .01 and R(2) = 0.10; P < .01, respectively). In multivariable analysis, the association between CRF and MD remained significant while CH to MD did not (P < .01 and P = .77). In the GDx ECC subgroup (204 eyes), there was a weak association between CH and CRF and average RNFL thickness (R(2) = 0.07; P < .01 and R(2) = 0.05; P < .01, respectively), which was not observed in the SD-OCT subgroup (146 eyes) (R(2) = 0.01; P = .30 and R(2) = 0.01; P = .21). After adjusting for central corneal thickness, age, and axial length, the relationship of CH and CRF to RNFL thickness no longer reached statistical significance. CONCLUSIONS The current study found only a weak relationship between corneal biomechanical parameters and measures of structural and functional damage in glaucoma.

Comparing polymethylmethacrylate implant with collagen implant in deep sclerectomy: a randomized controlled trial.

PurposeTo compare the intraocular pressure (IOP) lowering effect and safety of a new rigid, nonabsorbable polymethylmethacrylate implant (PMMA) with the commercially available cylindrical collagen implant used in deep sclerectomy procedure. InterventionNonpenetrating deep sclerectomy was performed on all patients. Patients were randomly assigned to receive either a PMMA implant or a collagen implant. MethodsThe trial involved 60 patients (60 eyes) with medically uncontrolled primary and secondary open-angle glaucoma who were randomized to receive either a PMMA implant (30 eyes) or the collagen implant (30 eyes). The patients were examined before and after the operation 1 day before surgery and at day 1; weeks 1, 2 and 3; and months 1, 2, 3, 6, 9, 12, 18, 24, and 30. At each visit, the following examinations were performed: slit lamp examination, tonometry, visual acuity, and fundoscopy. ResultsThe mean follow-up period was 20.4 (SD 12.4) months (PMMA) and 15.1 (SD 7.7) months (collagen) (P=NS). The mean preoperative IOP was 21.4 (SD 7.1) mm Hg (PMMA) and 21.0 mm Hg (SD 5.4) (collagen). The mean postoperative IOP was 7.4 (SD 4.5) mm Hg (PMMA) and 5.4 (SD 4.4) mm Hg (collagen) at day 1 (P=NS), 15.7 (SD 5.0) mm Hg (PMMA) and 14.7 (SD 5.0) mm Hg (collagen) at month 1 (P=NS), and 13.8 (SD 4.8) mm Hg (PMMA) and 13.3 (SD 2.4) mm Hg (collagen) at month 12 (P=NS). Seven patients had perforations of the trabeculo-Descemet membrane and were excluded from the analysis. At the last follow-up visit, 42% of PMMA patients and 44% of collagen patients achieved an IOP of 21 mm Hg or less without medication (P=NS). The number of medications was reduced from 2.4 (SD 1.0) to 0.6 (SD 0.6) (P<0.001) in the PMMA group, and from 2.4 (SD 1.1) to 0.7 (SD 0.8) (P<0.001) in the collagen group. There were no significant differences between the 2 groups in postoperative and transient complications. ConclusionsThe new PMMA implant offered success and complication rates equal to those of the collagen implant. The new PMMA implant could serve as a low-cost alternative to the collagen implant and render the use of deep sclerectomy with an implant affordable for settings with limited financial resources.