Radial peripapillary capillary density as a predictive factor for glaucoma in eyes with ocular hypertension. An observational, comparative, single-centred study.

Background: Ocular hypertension (OH) is a condition characterized by elevated intraocular pressure (IOP) exceeding the normal range, without any evident damage to the optic nerve or visual field defects characteristic of glaucoma. It constitutes a significant precursor to the development of glaucoma, a leading cause of irreversible vision loss worldwide. Emerging evidence has shown that microcirculation alterations in eyes with OH could serve as predicting factors to identify eyes at high risk for progression to glaucoma. In view of the above, the purpose of our study is to investigate microcirculation alterations of the radial peripapillary capillary plexus using optical coherence tomography angiography (OCT-A) in patients with ocular hypertension (OH). Methods: A total of 192 eyes were included in this observational, comparative, single-centre study and were divided in two groups: OH eyes and healthy controls. OCT-A was performed to analyze microcirculation characteristics at the peripapillary area. Radial peripapillary capillary density was measured at the total area of the optic disc and at each separate region (superior, inferior, inside). The parameters of age, medical treatment for ocular hypertension, sex and retinal fiber layer thickness were evaluated. Results: Total radial peripapillary capillary density was significantly lower in patients with OH than in healthy controls Concerning the microcirculation characteristics at each separate region of the peripapillary area, the results were as follows: inferior radial peripapillary capillary density was significantly decreased in individuals with OH than in controls, while measurements in the superior peripapillary area and internal optic disc were similar in both groups. Conclusions: Our study indicates decreased radial peripapillary capillary density in eyes with OH. Microcirculation alterations in the inferior peripapillary area could potentially comprise biomarkers for OH progression to glaucoma.

Efficacy and safety of dexamethasone intravitreal implant in patients with retinal vein occlusion resistant to anti-VEGF therapy: a 12-month prospective study.

Purpose: To evaluate the safety and efficacy of repeated intravitreal dexamethasone implant (Ozurdex) injections administrated on an "as-needed" protocol for retinal vein occlusion patients with macular oedema, previously subjected to at least five anti-vascular endothelial growth factor (VEGF) injections with poor or no response. Methods: Prospective interventional case series of 13 branch retinal vein occlusion (BRVO) and 10 central retinal vein occlusion (CRVO) patients with persistent macular oedema (>250 µm) after at least five anti-VEGF injections. Exclusion criteria included: baseline visual acuity worse than 1.5 logMAR, previous intravitreal implant, history of vitreoretinal surgery, manifest glaucoma or ocular hypertension, epiretinal membrane, retinal neovascularization, massive retinal or macular ischaemia, vitreous haemorrhage or severe lens opacity, previous laser photocoagulation treatment. Each patient received an initial intraocular dexamethasone implant and the procedure was repeated at 6 months "as needed." Patients were followed up at months 2, 4, 6, 8, 10 and 12 with spectral domain optical coherence tomography and best corrected visual acuity measurements. Exclusion criteria included: baseline visual acuity worse than 1.5 logMAR, previous intravitreal implant, history of vitreoretinal surgery, manifest glaucoma or ocular hypertension, epiretinal membrane, retinal neovascularization, retinal or macular ischaemia, vitreous haemorrhage or severe lens opacity, previous laser photocoagulation treatment. Patients on topical or systemic corticosteroid therapy (during the last 3 months), and known steroid responders as well as diabetic patients were also excluded. Results: In the BRVO group, the mean central retinal thickness (CRT) and best corrected visual acuity (BCVA) significantly improved from 482.92 ± 139.99 µm (0.55 ± 0.12 logMAR) at baseline, to 369.31 ± 119.72 µm (0.43 ± 0.18 logMAR) at 6 months (p = 0.011/p = 0.019). At 12 months CRT was 295.82 ± 135.48 µm (p = 0.026) and BCVA 0.29 ± 0.17 logMAR (p = 0.002). Minimum CRT values were achieved at 3.45 months after the first injection, and 2.46 months after the second injection (197.00 ± 84.27 and 180.00 ± 76.89 µm, respectively). Best BCVA values were achieved at a mean of 4 ± 0.853 months after the first injection, and 4 months after the second injection (0.219 ± 0.129 and 0.222 ± 0.078 logMAR, respectively). In the CRVO group, neither the mean CRT nor BCVA improved significantly at 6 months: from 669.70 ± 203.20 µm (0.80 ± 0.231 logMAR) at baseline, to 586.20 ± 237.63 µm (0.740 ± 0.268 logMAR) at 6 months (p = 0.131/p = 0.333). At 12 months CRT was significantly improved: 549.90 ± 191.26 µm (p = 0.047), but BCVA lacked significant improvement: 0.690 ± 0.285 logMAR (p = 0.072). Minimum CRT values were achieved at a mean of 2 months after the first injection, and also 2 months after the second injection (261.60 ± 121.31 and 280.00 ± 177.43 µm, respectively). Best BCVA values were achieved at a mean of 2 months after the first injection, and 2 months after the second injection and were 0.390 ± 0.173 and 0.385 ± 0.233 logMAR, respectively. Cataract progression was a rare event (2/23 eyes), while transient steroid-induced ocular hypertension (5/23 eyes) was managed successfully with IOP-lowering medication Conclusion: Dexamethasone implant should be considered as an effective and safe alternative in patients with BRVO and CRVO who have failed anti-VEGF therapy. Shortening the re-injection interval especially for CRVO cases should be considered.

Endothelial keratoplasty in eyes with a retained angle-supported intraocular lens.

PURPOSE: To describe the outcomes of endothelial keratoplasty (EK) for bullous keratopathy in eyes with a retained angle-supported anterior chamber intraocular lens (acIOL). METHODS: Among 263 consecutive EK procedures, 7 DMEK and 11 DSAEK procedures were identified in eyes with an acIOL and included in the present retrospective case series. Pre- and postoperative status including ocular history, anatomical outcome and complications as well as best-corrected visual acuity was evaluated. RESULTS: Ocular history included complicated cataract surgery (n = 11), ocular trauma (n = 4) and primary intracapsular cataract extraction (n = 3). Surgery-related complications included primary graft failure (n = 1), graft detachment (n = 1), endophthalmitis (n = 1) and allograft rejection (n = 1). A clear cornea at the final examination (14 ± 4 months) was observed in 14/18 (78%), while the visual outcome was limited due to significant ocular comorbidity in 9 out of 14 uncomplicated procedures. CONCLUSION: The presented short-term outcomes suggest that both DMEK and DSAEK are feasible in eyes with an angle-supported acIOL yielding an acceptable graft survival rate in the first postoperative year.

Pars Plana Vitrectomy for Vitreomacular Traction Syndrome: Analysing the Preoperative Prognostic Factors.

PURPOSE: To identify the prognostic factors affecting the surgical outcomes in patients with vitreomacular traction syndrome undergoing pars plana vitrectomy. METHODS: This was a retrospective clinical study of 67 eyes of 67 patients with vitreomacular traction syndrome who underwent pars plana vitrectomy. Demographic, clinical, and optical coherence tomography (OCT) characteristics were collected and analyzed. Univariate and multivariate linear regression analysis were used to examine the effect of parameters on change in best-corrected visual acuity (BCVA). RESULTS: At a mean follow-up period of 15.9±12 months (mean±SD), the BCVA improved from 0.7±0.3 LogMAR (mean±SD) to 0.5±0.3. Seven patients developed full-thickness macular hole intraoperatively and tamponade (air, 20% SF6 or 12% C3F8) was used in 41 patients. Retinal breaks were identified intraoperatively in four patients. Regression analysis demonstrated that the preoperative BCVA was the only parameter affecting the postoperative visual outcome. CONCLUSION: In the present study, the preoperative BCVA plays a predictive role in the surgical outcome of patients with VMT undergoing pars plana vitrectomy. No other preoperative OCT characteristics demonstrated prognostic potential. Further prospective studies are needed in order to examine the role of several factors that could potentially facilitate preoperative patient counselling.

Isolated descemetorhexis for anterior synechiolysis prior to endothelial keratoplasty - case report and technique.

PURPOSE: To describe the utilization of descemetorhexis for reformation of the anterior chamber in eyes with central iridocorneal synechiae before endothelial keratoplasty (EK). METHODS: A 71-year-old man with a history of trabeculectomy complicated by hypotony presented with bullous keratopathy in the presence of extensive iridocorneal synechiae and a flat anterior chamber. In order to proceed with EK, synechiolysis with the use of viscoelastic and scissors was attempted. Despite successful dissection of the peripheral strands, the pupillary margin of the iris remained attached to the endothelium. Therefore, descemetorhexis was performed to detach the Descemet membrane along with central synechiae and create sufficient space for safe EK at a later stage. RESULTS: Corneal clarity was restored by ultrathin Descemet stripping automated endothelial keratoplasty, leaving a fibrous membrane in the pupillary plane, which was excised 2 months later, allowing an improvement of best-corrected visual acuity to 0.5. CONCLUSION: Isolated descemetorhexis was successfully employed to reform the anterior chamber and proceed with EK in a case of bullous keratopathy and resistant iridocorneal synechiae. This stepwise approach may be considered in similar cases in order to avoid a more invasive treatment, ie, penetrating keratoplasty and synechiolysis.

Comparison of Goldmann applanation tonometry and Pascal dynamic contour tonometry in relation to central corneal thickness and corneal curvature.

PURPOSE: The aim of the study was to assess the influence of central corneal thickness (CCT) and corneal curvature in tonometry measurements taken by Goldmann applanation tonometry (GAT) and Pascal dynamic contour tonometry (DCT). METHODS: This was a prospective study of 185 eyes from 97 subjects, attending outpatient ophthalmology appointments, who underwent intraocular pressure measurements by GAT and Pascal DCT. CCT and corneal curvature were obtained using ultrasound pachymetry and Orbscan topography, respectively. All measurements were carried out among males and females during the period 2009-2012. Apart from the usual descriptive and exploratory data analysis, one-way analysis of variance and agreement analysis were performed, linear as well as intraclass correlation coefficients were estimated, and multiple scatter and Bland-Altman plots were produced. RESULTS: Mean IOP measurements obtained were 17.21±4.10 mmHg by DCT and 13.23±4.07 mmHg by GAT. Mean difference between the GAT and DCT measurements was 3.88±2.8 mmHg. Mean CCT and corneal curvature were 522.78±52 µm and 43.83±2.9823 D, respectively. CONCLUSION: Intraocular pressure measured by GAT was consistently lower when compared with DCT, and this difference was greatest with thinner CCT. Flat corneas seem to influence GAT measurements compared to DCT.

Predictive Value of HRT Stereometric Parameters and Blue-on-Yellow Perimetry Global Indices in Glaucoma-suspected Subjects.

OBJECTIVE: To determine subtle changes of Heidelberg retina tomography (HRT) stereometric parameters and blue-on-yellow (B/Y) perimetry global indices for the early diagnosis of glaucoma in suspected subjects. PATIENTS AND METHODS: Cross-sectional data on 174 eyes of 87 subjects from a larger cohort, attending the Glaucoma Department of the "G. Gennimatas" General Hospital of Athens from January 2004 to February 2014, were used in the study. Subjects were assigned to 3 groups: (a) "normals" not requiring treatment throughout the study (group 1), (b) suspects who developed glaucoma and required treatment during the study (group 2), and (c) patients with incipient glaucoma (group 3). Specific HRT and B/Y perimetry variables were compared among the 3 groups. RESULTS: Significant differences were established for the following HRT parameters: "reference height" differed significantly between groups 1 and 2 and groups 1 and 3; "cup shape measure" differed significantly between groups 1 and 2 and groups 2 and 3. B/Y perimetry global index "mean deviation" significantly distinguished group 2 from groups 1 and 3. CONCLUSIONS: The results of the present study suggest the predictive value of the HRT stereometric parameters "reference height" and "cup shape measure" and of the B/Y perimetry global index "mean deviation" in glaucoma-suspected subjects; further corroboration through longitudinal studies is warranted.

ß-Thalassemia and ocular implications: a systematic review.

BACKGROUND: Beta-thalassemia is a severe genetic blood disorder caused by a mutation in the gene encoding for the beta chains of hemoglobin. Individuals with beta-thalassemia major require regular lifelong Red Blood Cell transfusions to survive. Ocular involvement is quite common and may have serious implications. METHODS: Extensive review of observational studies on beta-thalassemia, to determine the prevalence and spectrum of ocular abnormalities, by clinical examination and multimodal imaging, and to investigate risk factors for their development. RESULTS: Frequency of ocular involvement differs among various studies (41.3-85 %, three studies). Ocular findings in beta-thalassemia may correlate to the disease itself, iron overload or the chelating agents used. Beta-thalassemia ocular manifestations include ocular surface disease, as demonstrated by tear function parameters (two studies). Lens opacities are present in 9.3-44 % (five studies). Lenticular opacities and RPE degeneration correlated positively with use of desferrioxamine and deferriprone respectively (two studies). Ocular fundus abnormalities characteristic of pseudoxanthoma elasticum (PXE), including peau d'orange, angioid streaks, pattern dystrophy-like changes, and optic disc drusen are a consistent finding in seven studies. Patients with PXE-like fundus changes were older than patients without these fundus changes (two studies). Age (two studies) and splenectomy (one study) had the strongest association with presence of PXE-like fundus changes. Increased retinal vascular tortuosity independently of the PXE-like fundus changes was found in 11-17.9 % (three studies), which was associated with aspartate amino transferase, hemoglobin and ferritin levels (two studies). Fundus autofluorescence and electrophysiological testing (ERG and EOG) may indicate initial stages or more widespread injury than is suggested by fundus examination (two studies). CONCLUSIONS: Beta-thalassemia may present with various signs, both structural and functional. Pseudoxanthoma elasticum like fundus changes are a frequent finding in patients with b-thalassemia. These changes increase with duration or severity of the disease. Retinal vascular tortuosity may be an additional disease manifestation related to the severity and duration of anemia and independent of the PXE-like syndrome. Patients with long-standing disease need regular ophthalmic checkups because they are at risk of developing PXE-like fundus changes and potentially of subsequent choroidal neovascularization.

Safety and efficacy of phacoemulsification and intraocular lens implantation through a small pupil using minimal iris manipulation.

PURPOSE: The aim of this study was to compare the results of phacoemulsification through a small pupil using minimal iris manipulation versus phacoemulsification through a well-dilated pupil. METHODS: This prospective randomized control (comparative) study comprised 78 patients (group I) with a maximally dilated pupil size of ≤4.00 mm and 45 patients (group II) with dilated pupil size of ≥7.00 mm. In group I patients, only viscodilation and minimal push-and-pull iris stretching with two collar-button iris-retractor hooks were utilized without iris manipulation. Phacoemulsification was performed by two senior surgeons and the technique used consisted of either stop and chop or quick chop, infusion/aspiration of lens cortex, capsular bag refill with ocular viscoelastic devices, and implantation of an acrylic foldable intraocular lens. Patients were examined on the first day and 1 month postoperatively. RESULTS: Forty-six eyes of group I patients had pseudoexfoliation syndrome, eleven eyes had previous glaucoma surgery, 14 eyes had angle-closure or open-angle glaucoma, and seven eyes had posterior synechiae with iritis. In group I patients, the mean pupil size measured under an operating microscope was 3.2 mm preoperatively, 4.3 mm after viscoelastic and mechanical pupil dilation, and 4.1 mm at the end of a surgical procedure. Rupture of the zonular fibers occurred in six patients of group I and the intraocular lens was implanted in the sulcus. Small iris-sphincter rupture and small hemorrhages occurred in four eyes during pupillary manipulation, but they were not evident at the end of the surgery. In group II patients, no intraoperative complications occurred. Signs of significant corneal edema and iritis were observed more frequently in group I eyes (26 eyes and 20 eyes, respectively) on the first postoperative day in comparison with group II eyes (ten eyes and six eyes, respectively). Intraocular pressure was <20 mmHg in all eyes of both groups. One month postoperatively, the pupil was round and reactive to light, the anterior chamber was quiet, and the cornea was clear in all eyes. The best-corrected visual acuity on Snellen chart was 20/40 (Monoyer's scale) or better in both groups. CONCLUSION: Phacoemulsification through a small pupil using minimal iris manipulation can be safe and exhibits the same results as those obtained with phacoemulsification through normal pupils.

Trabeculectomy with Healaflow versus Trabeculectomy for the Treatment of Glaucoma: A Case-Control Study.

Purpose. To compare the outcomes of trabeculectomy with and without Healaflow (Anteis S.A, Geneva, Switzerland), a high molecular weight viscoelastic gel, in patients requiring glaucoma surgery. Methods. This was a retrospective, comparative, interventional case-control study. Forty patients formed two matched study groups and were analyzed (trabeculectomy alone (control) versus trabeculectomy with Healaflow (study)). Results. The postoperative levels of mean IOP were statistically significantly lower (P < 0.05) than preoperatively in both groups, for all time intervals. There was no statistical difference, at the end of the follow-up period, between the two groups in the mean values of the IOP (14.9 ± 3.2 mmHg for the study group versus 14.8 ± 3.3 mmHg for the control group). The number of antiglaucoma drugs used in the study group was reduced from a preoperative mean of 3.4 ± 0.75 to a 6-month postoperative mean of 0.6 ± 0.8 (P < 0.001) and in the control group from 3.6 ± 0.59 to 0.55 ± 0.9 (P < 0.001). Conclusions. Although trabeculectomy with Healaflow appears to be a safe procedure, we failed to identify any significant advantages in the use of Healaflow when compared with trabeculectomy alone, at the end of the 6-month follow-up period.

Ophthalmic Metastasis of Breast Cancer and Ocular Side Effects from Breast Cancer Treatment and Management: Mini Review.

Breast cancer is one of the most common malignant diseases occurring in women, and its incidence increases over the years. It is the main site of origin in ocular metastatic disease in women, and, due to its hematogenous nature of metastatic spread, it affects mainly the uveal tissue. The purpose of this paper is to summarize the clinical manifestations of the breast cancer ocular metastatic disease, alongside the side effects of the available treatment options for the management and regression of the systematic and ophthalmic disease.

Post-cataract surgery diplopia: aetiology, management and prevention.

Diplopia is an infrequent but distressing adverse outcome after uncomplicated cataract surgery. Many factors may contribute to the occurrence of this problem, including prolonged sensory deprivation resulting in disruption of sensory fusion, paresis of one or more extraocular muscles, myotoxic effects of local anaesthesia, optical aberrations (for example, aniseikonia) and pre-existing disorders (for example, thyroid orbitopathy). The purpose of this review is to present the aetiology and clinical features of diplopia after cataract surgery and to discuss the possible modalities for the prevention and treatment of this frustrating complication.

Comparison of the nerve fiber layer of type 2 diabetic patients without glaucoma with normal subjects of the same age and sex.

BACKGROUND: The retinal nerve fiber layer (RNFL) thickness in patients with diabetes mellitus type 2 was compared to normal subjects of similar age and sex, having first excluded any risk factors for glaucoma. The correlation between the RNFL thickness and the severity of diabetic retinopathy was investigated at its primary stages and with other ocular and diabetic parameters. METHODS: A prospective, case series study was carried out. Twenty-seven diabetic patients without diabetic retinopathy, 24 diabetic patients with mild retinopathy, and 25 normal, age-matched subjects underwent a complete ophthalmological examination and imaging with scanning laser polarimetry for the evaluation of the RNFL. Multivariate analysis was applied in order to investigate the correlation between RNFL and diabetic parameters, such as age, duration of diabetes, insulin therapy, levels of glycosylated hemoglobin; and ocular parameters, such as cup to disc ratio, levels of normal intraocular pressure, and central corneal thickness. RESULTS: The mean inferior average of RNFL and the temporal-superior-nasal-inferior-temporal standard deviation were statistically significantly lower in both diabetic groups, and the nerve fiber index was higher (P=0.04) compared to the normal group. There was no statistically significant difference between the diabetic groups. The factor analysis showed no significant correlation between the RNFL and the previously mentioned diabetic and ocular parameters. CONCLUSION: The existence of diabetes should be seriously considered in evaluating the results of scanning laser polarimetry. Multivariate analysis for RNFL was used for the first time.

Renal injury following intravitreal anti-VEGF administration in diabetic patients with proliferative diabetic retinopathy and chronic kidney disease--a possible side effect?

The use of intravitreal injections of anti-Vascular Endothelial Growth Factor (anti-VEGF) has been used for a broad spectrum of ocular pathologic entities. Although the dose of anti-VEGF agents used for treating eye disease is minute compared with that used intravenously, intraocular administration can lead to systemic absorption and reduce serum VEGF levels. Several systemic side effects, such as hypertension and cardiovascular complications have been rarely reported in the literature. Renal complications of intravenous administration of anti-VEGF, are well known and include a variety of renal pathological damage which can induce proteinuria and hypertension. We describe herein, 2 cases of diabetic patients with preexisting kidney disease who presented severe reduction of their renal function after intraocular administration of anti-VEGF. Although a cause -effect correlation cannot be established unless further studies are performed, we believe that pretreatment counseling should include a discussion outlining the possible risk of aggravating of the renal function in patients with kidney disease. Close cooperation with the patient's nephrologist and close monitoring of the patient may be required, in such cases, in order to monitor the renal function before and after the intravitreal administration of anti-VEGF.

Clinical trial evaluating Viscoat and Visthesia ophthalmic viscosurgical devices in corneal endothelial loss after cataract extraction and intraocular lens implantation.

PURPOSE: To assess and compare the safety and the efficacy of VisThesia™ and Viscoat® in cataract surgery. METHODS: This prospective randomized clinical trial included 44 eyes of 44 patients that were assigned randomly to undergo phacoemulsification either with VisThesia™ or with Viscoat®. Preoperative data included age, gender, visual acuity, IOP and mean endothelial cell density. Postoperative, best corrected visual acuity (BCVA), IOP, mean endothelial cell density and painful sensation during surgery were recorded. RESULTS: BCVA, evaluated with Snellen chart in decimal fraction, was statistically improved in both groups. Specifically, mean BCVA in VisThesia group was increased from 0.28 ± 1.8 SD preoperatively to 0.83 ± 1.4 SD postoperatively, whereas, in the Viscoat group, BCVA was increased from 0.31 ± 2.1 SD preoperatively, to 0.85 ± 1.2 SD after surgery (p > 0.1). The mean postoperative IOP was lower in the VisThesia group, but the difference was not statistically significant (p > 0.1). Preoperatively, the mean endothelial cell count was 2322.3 ± 161.1 SD cells/mm(2) in Viscoat group and 2304.8 ± 142.8 SD cells/mm(2) in the VisThesia group, similar between groups (p > 0.1). At day 15 after cataract surgery the postoperative endothelial cell count was 2102.9 ± 182.8 SD cells/mm(2) in Viscoat group and 2032.6 ± 160.4 SD cells/mm(2) in the VisThesia group (p > 0.1). The mean endothelial cell decrease was 212 cells/mm(2) (9.1%) in the Viscoat group and 272 cells/mm(2) (11.8%) in the VisThesia group. The difference was not statistically significant between the two groups (t-test = 0.18, p > 0.1). This value is within standard normal endothelial cell decrease after a cataract surgery. Painful sensation was not reported during any stage of the procedure. CONCLUSIONS: Topical-intracameral anesthesia with VisThesia™ allows cataract surgery without any painful sensation in the majority of patients. Both Viscoat® and VisThesia™ have similar safety profile during intra- and post-operative period and identical endothelial protection, as endothelial cell loss is within normal limits.

Comparison of SWAP and SAP on the point of glaucoma conversion.

BACKGROUND: The purpose of this study was to compare the two perimetric modalities, SWAP (short wavelength automated perimetry) and SAP (standard automated perimetry), on the point of conversion to glaucoma. METHODS: In this prospective, longitudinal, follow-up study, 282 patients with ocular hypertension were recruited consecutively and tested with both SAP and SWAP annually for 5 years or until the onset of conversion to glaucoma. SAP and SWAP perimetry was performed with the Humphrey Field Analyzer II using the 24-2 full-threshold test. Abnormality for both SAP and SWAP fields was determined on the pattern deviation plot and defined as either a) one point below the 0.5% probability level or b) a cluster of 2 or more points below 1% or c) a cluster of 3 or more points below 2% or d) a cluster of 4 or more points below 5%. Abnormal tests had to be confirmed on a subsequent test within one year to be classified as conversion. RESULTS: Of the 282 patients initially recruited, 32 were excluded. Of the 250 remaining patients, a total of 38 converted during the follow-up period; 36.8% of conversions were detected earlier with SWAP, 29% simultaneously, and 34.2% were not detected with SWAP during the follow-up period; 2.4% of patients showed SWAP visual field loss that did not result in conversion during the follow-up period. CONCLUSION: The results in our study are inconclusive. There were patients with earlier, simultaneous, or no SWAP conversion, with SAP conversion as the golden standard criterion. One should consider both SAP and SWAP with confirmation when visual field loss is evident to maximize early detection of glaucoma, because it appears that each method identifies early glaucoma in a subset of patients and these subsets overlap only partially.