Tiago Santos Prata

Effect of Diabetic Retinopathy and Panretinal Photocoagulation on Retinal Nerve Fiber Layer and Optic Nerve Appearance

OBJECTIVE To determine if panretinal photocoagulation (PRP) alters retinal nerve fiber layer (RNFL) thickness and optic nerve appearance. METHODS Patients with diabetes who did and did not undergo PRP and nondiabetic control subjects were enrolled in a prospective study. Participants underwent optical coherence tomography of the peripapillary retina and optic nerve. Stereoscopic optic nerve photographs were graded in a masked fashion. RESULTS Ninety-four eyes of 48 healthy individuals, 89 eyes of 55 diabetic patients who did not undergo PRP, and 37 eyes of 24 subjects with diabetes who underwent PRP were included in this study. Eyes that had been treated with PRP had thinner peripapillary RNFL compared with the other groups; this was statistically significantly different in the inferior (P = .004) and nasal (P = .003) regions. Optic nerve cupping did not increase with severity of disease classification, but the proportion of optic nerves graded as suspicious for glaucoma or as having nonglaucomatous optic neuropathy did (P = .008). These grading categories were associated with thinner RNFL measurements. CONCLUSIONS Diabetic eyes that have been treated with PRP have thinner RNFL than nondiabetic eyes. Optic nerves in eyes treated with PRP are more likely to be graded as abnormal, but their appearance is not necessarily glaucomatous and may be related to thinning of the RNFL.

Spectral-domain optical coherence tomography for early glaucoma assessment: analysis of macular ganglion cell complex versus peripapillary retinal nerve fiber layer

OBJECTIVE We sought to compare the glaucoma discrimination ability of macular inner retinal layer (MIRL) thickness with that of conventional peripapillary retinal nerve fiber layer (pRNFL) thickness as measured by spectral-domain optical coherence tomography (SD-OCT) in patients with early glaucoma. DESIGN Cross-sectional study. PARTICIPANTS We studied 67 patients with early glaucoma (visual field mean deviation index ≥-6 dB), and 56 healthy subjects were prospectively enrolled. METHODS All patients underwent MIRL thickness measurement (ganglion cell complex [GCC] scan) and pRNFL thickness measurement (3.45 mm scan) by SD-OCT. Whenever both eyes were eligible, one was randomly selected. Receiver operating characteristic curves and sensitivities at fixed specificities were generated for different parameters. The areas under the receiver operating characteristic curves (AUCs) of each parameter were compared. RESULTS The average mean deviation for the glaucomatous eyes was -2.5 ± 1.6 dB. The AUCs for average (0.815); superior (0.807); and inferior (0.788) MIRL thicknesses were not significantly different (p ≥ 0.18). The AUCs for average (0.735); superior (0.728); and inferior (0.697) pRNFL thicknesses were also similar (p ≥ 0.15). Average MIRL thickness had a significantly larger AUC compared to average pRNFL thickness analysis (0.815 vs 0.735; p = 0.03). Sensitivities at 80% specificity for average MIRL and pRNFL thicknesses were 66.7% (cutoff, 89.9 μm) and 62.9% (cutoff, 111.8 μm), respectively. CONCLUSIONS The GCC scan showed a similar or even a slightly better ability to discriminate between healthy and early glaucomatous eyes compared to the pRNFL scan. Different from previous analyses considering total macular thickness, the GCC macular scan seems to be a useful tool for identification of early structural damage in patients with glaucoma.

Association between corneal biomechanical properties and optic nerve head morphology in newly diagnosed glaucoma patients

Background:  To investigate the association between corneal biomechanics and optic nerve head morphology in newly diagnosed primary open‐angle glaucoma patients.

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients.

PurposeTo investigate factors associated with changes in optic nerve head (ONH) topography after acute intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG).MethodsUntreated POAG patients (IOP >21 mm Hg) were prospectively enrolled. Systemic and ocular information were collected, including central corneal thickness (CCT) and corneal hysteresis (CH). All patients underwent confocal scanning laser ophthalmoscopy and tonometry (Goldmann) before and 1 h after pharmacological IOP reduction. The mean of three measurements was considered for analysis. Changes in each ONH topographic parameter were assessed (one eye was randomly selected), and those that changed significantly were correlated with patients systemic and ocular characteristics.ResultsA total of 42 patients were included (mean age, 66.7±11.8 years). After a mean IOP reduction of 47.3±11.9%, significant changes were observed in cup area and volume, and in rim area and volume (P<0.01), but not in mean cup depth (P=0.80). Multiple regression analysis (controlling for baseline IOP and magnitude of IOP reduction) showed that CH (r2=0.17, P<0.01) and diabetes diagnosis (r2⩾0.21, P<0.01) were negatively correlated with the magnitude of changes in ONH parameters, whereas the cup-to-disc ratio was positively correlated (r2=0.30, P<0.01). Age, race, disc area, and CCT were not significant (P⩾0.12). Including all significant factors in a multivariable model, only the presence of diabetes remained significantly associated with all ONH parameters evaluated (P<0.01).ConclusionsDifferent systemic and ocular factors, such as diabetes, CH, and the relative size of the cup, seem to be associated with the magnitude of changes in ONH topography after acute IOP reduction in POAG patients. These associations partially explain the ONH changes observed in these patients and suggest that other factors are possibly implicated in an individual susceptibility to IOP.

Retinal vascular occlusions occur more frequently in the more affected eye in exfoliation syndrome

PurposeTo evaluate the relationship between retinal vascular occlusions (RVOs) and exfoliation syndrome (XFS) in a cohort of patients with the two conditions.MethodsWe reviewed the records of patients with XFS with or without glaucoma and any type of RVO between 1983 and 2007. Patients with prior incisional surgery or a history of uveitis were excluded. Data collected included demographics, systemic comorbidities, type of RVO, and intraocular pressure (IOP) before the RVO. Slit-lamp biomicroscopy regarding the presence of exfoliation material on the lens capsule and pupillary margin before the vascular event was used to evaluate the laterality and degree of XFS.ResultsWe identified 36 patients (mean age 78.4±8.3 years, 19 women). Most patients were of European descent (34/36) and 20 (56%) had no prior glaucoma diagnosis. The most common retinal vascular events were central retinal vein occlusion (18/36) and BRVO (10/36). Mean IOP between eyes with (19.5±6.5 mm Hg) and without (17.9±4.8 mm Hg) RVO was similar (P=0.12). RVOs occurred more commonly in the eye with more pronounced XFS in 92% (33/36) of the cases. A similar agreement was found when considering patients with and without glaucoma separately (94% (15/16) vs90% (18/20); P=0.83). In addition, no difference in the agreement percentage was observed when comparing patients with unilateral XFS (87% (13/15)) with all study patients (P=0.87).ConclusionsRetinal vascular occlusion in patients with XFS occurs most often in the affected or more severely affected eye. As vascular occlusions happened in patients with and without glaucoma in similar proportions, the presence of XFS seems to play an important role in these findings.

Concentração de proteínas no humor aquoso de pacientes com glaucoma primário de ângulo aberto em tratamento clínico

PURPOSE: To compare total protein concentration in the aqueous humor of primary open-angle glaucoma and non-glaucomatous patients. METHODS: Aqueous humor samples were obtained from 22 patients just before trabeculectomy for clinically uncontrolled primary open angle glaucoma (POAG group). Aqueous humor (0.1 mL) was aspirated by inserting a 26-gauge needle into the anterior chamber. The same procedure was performed in 22 non-glaucomatous patients just before cataract surgery (control group). Immediately after collection, the aqueous humor was stored at -20°C. Aqueous humor total protein concentration was determined using a colorimetric assay. RESULTS: The geometric mean of total protein concentration of the aqueous humor samples was 32 mg/dL (range: 8-137 mg/dL) in the primary open angle glaucoma group and 16 mg/dL (range: 2-85 mg/dL) in the control group. The ratio of the protein concentration between the two groups was 2.0 (95% confidence interval: 1.3 to 3.2; p=0.003). CONCLUSIONS: The total protein concentration in primary open-angle glaucoma aqueous humor was approximately two times higher than that in non-glaucomatous subjects.

Factors affecting the variability of the Heidelberg Retina Tomograph III measurements in newly diagnosed glaucoma patients

PURPOSE To determine factors associated with the test-retest variability of optic nerve head (ONH) topography measurements with confocal scanning laser ophthalmoscopy (CSLO) in newly diagnosed glaucomatous patients. METHODS Consecutive patients with newly diagnosed primary open-angle glaucoma were prospectively enrolled. Patients presenting with any ocular disease other than glaucoma were excluded. All patients underwent CSLO using the Heidelberg Retina Tomograph III (HRT-III) in one randomly selected eye (three consecutive scans; performed by the same examiner). For each Heidelberg Retina Tomograph III parameter, repeatability was assessed using within subject standard deviation (Sw) and coefficient of variation (CVw), repeatability coefficient (RC) and intraclass correlation coefficient (ICC). Scatter plots and regression lines were constructed to identify which factors influenced test-retest measurement variability. RESULTS A total of 32 patients were included (mean age, 65.4 ± 13.8 years). Most patients were female (65%) and white (50%). Among all Heidelberg Retina Tomograph III parameters evaluated, rim area and mean cup depth had the best measurement repeatability. Vertical cup-to-disc ratio (CDR, as determined by optic disc stereophotograph examination) was significantly associated (R²=0.21, p<0.01) with test-retest measurement variability. Eyes with larger CDR showed less variable measurements. Other factors, including age, disc area, central corneal thickness and intraocular pressure were not significant (p>0.14). CONCLUSION Heidelberg Retina Tomograph III showed good test-retest repeatability for all ONH topographic measurements, mainly for rim area and mean cup depth. Test-retest repeatability seemed to improve with increasing CDR. These findings suggest that HRT-III topographic measurements should be cautiously interpreted when evaluating longitudinally glaucoma patients with early structural damage (small CDR).

Perioperative management of anticoagulant users scheduled for glaucoma surgery: a survey among the Brazilian Glaucoma Society members

PURPOSE To investigate and describe, among the members of the Brazilian Glaucoma Society (BGS), the practices regarding the perioperative management of anticoagulants (warfarin and aspirin) use in patients scheduled for glaucoma surgery. METHODS The active members of the Brazilian Glaucoma Society answered a questionnaire evaluating different aspects of their current perioperative management of glaucomatous patients taking warfarin or aspirin. RESULTS A total of 52 participants returned a complete questionnaire. Warfarin or aspirin was routinely interrupted prior to glaucoma surgery by 82.7% of the respondents. The majority of the surgeons who discontinued these medications reported doing so 7 days prior to surgery and resumed their use the day after the procedure. Almost half of our interviewees reported hemorrhagic complications that could be related to anticoagulant therapy. A large number of the surgeons (86.5%) preferred a particular surgical technique for anticoagulated patients; however, most of them (88.5%) do not change the anesthetic planning in such patients. Finally, the majority of the participants (90.4%) refer their anticoagulated patients to a preoperative appointment with a cardiologist or a general practitioner before the surgery. CONCLUSIONS The majority of Brazilian Glaucoma Society members participating in this study interrupt either warfarin or aspirin prior to glaucoma surgery. Although there is scant information available in the literature to offer definitive guidance, most participants from the Brazilian Glaucoma Society seem to share the same opinion when it comes to perioperative management of anticoagulant users.

Intraocular pressure, corneal thickness, and corneal hysteresis in Steinert's myotonic dystrophy

PURPOSE Low intraocular pressure (IOP) measured by Goldmann applanation tonometry (GAT) is one of the ocular manifestations of Steinerts myotonic dystrophy. The goal of this study was to evaluate the corneal-compensated IOP as well as corneal properties (central corneal thickness and corneal hysteresis) in patients with myotonic dystrophy. METHODS A total of 12 eyes of 6 patients with Steinerts myotonic dystrophy (dystrophy group) and 12 eyes of 6 age-, race-, and gender-matched healthy volunteers (control group) were included in the study. GAT, Dynamic Contour Tonometry (DCT-Pascal) and Ocular Response Analyzer (ORA) were used to assess the IOP. Central corneal thickness was obtained by ultrasound pachymetry, and corneal hysteresis was analyzed using the ORA device. In light of the multiplicity of tests performed, the significance level was set at 0.01 rather than 0.05. RESULTS The mean (standard deviation [SD]) GAT, DCT, and corneal-compensated ORA IOP in the dystrophy group were 5.4 (1.4) mmHg, 9.7 (1.5) mmHg, and 10.1 (2.6) mmHg, respectively. The mean (SD) GAT, DCT, and corneal-compensated ORA IOP in the control group was 12.6 (2.9) mmHg, 15.5 (2.7) mmHg, and 15.8 (3.4) mmHg, respectively. There were significant differences in IOP values between dystrophy and control groups obtained by GAT (mean, -7.2 mmHg; 99% confidence interval [CI], -10.5 to -3.9 mmHg; P<0.001), DCT (mean, -5.9 mmHg; 99% CI, -8.9 to -2.8 mmHg; P<0.001), and corneal-compensated ORA measurements (mean, -5.7 mmHg; 99% CI, -10.4 to -1.0 mmHg; P=0.003). The mean (SD) central corneal thickness was similar in the dystrophy (542 [31] µm) and control (537 [11] µm) groups (P=0.65). The mean (SD) corneal hysteresis in the dystrophy and control groups were 11.2 (1.5) mmHg and 9.7 (1.2) mmHg, respectively (P=0.04). CONCLUSIONS Patients with Steinerts myotonic dystrophy showed lower Goldmann and corneal-compensated IOP in comparison with healthy individuals. Since central corneal thickness and corneal hysteresis did not differ significantly between groups, the lower IOP readings documented in this dystrophy seem not to be related to changes in corneal properties.

Imaging of a traumatic cyclodialysis cleft in a child using slit-lamp-adapted optical coherence tomography

Imaging of a traumatic cyclodialysis cleft in a child using slit-lamp-adapted optical coherence tomography