Blue-on-yellow perimetry can predict the development of glaucomatous visual field loss

Central Visual Field Testing in Early Glaucoma: A Report by the American Academy of Ophthalmology

PURPOSE

To evaluate the current published literature on the utility of the 10-2 visual field (VF) testing strategy for the evaluation and management of early glaucoma, defined here as mean deviation (MD) better than -6 decibels (dB).

METHODS

A search of the peer-reviewed literature was last conducted in June 2023 in the PubMed database. Abstracts of 986 articles were examined to exclude reviews and non-English-language articles. After inclusion and exclusion criteria were applied, 26 articles were selected, and the panel methodologist rated them for strength of evidence. Thirteen articles were rated level I, and 8 articles were rated level II. The 5 level III articles were excluded. Data from the 21 included articles were abstracted and reviewed.

RESULTS

The central 12 locations on the 24-2 VF test grid lie within the central 10 degrees covered by the 10-2 VF test. In early glaucoma, defects detected within the central 10 degrees generally agree between the 2 tests. Defects within the central 10 degrees of the 24-2 VF test can predict defects on the 10-2 VF test, although the 24-2 may miss defects detected on the 10-2 VF test. In addition, results from the 10-2 VF test show better association with findings from OCT scans of the macular ganglion cell complex. Modifications of the 24-2 test that include extra test locations within the central 10 degrees improve detection of central defects found on 10-2 VF testing.

CONCLUSIONS

Evidence to date does not support routine testing using 10-2 VF for patients with early glaucoma. However, early 10-2 VF testing may provide sufficient additional information for some patients, particularly those with a repeatable defect within the central 12 locations of the standard 24-2 VF test or who have inner retinal layer thinning on OCT scans of the macula.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Degree of loss in the tissue thickness, microvascular density, specific perimetry and standard perimetry in early glaucoma

Objective

To identify the degree of loss of the circumpapillary retinal nerve fibre layer (cpRNFL), the layer from the macular RNFL to the inner plexiform layer (mGCL++), circumpapillary (cpVD) and macular vascular density (mVD), Pulsar perimetry and standard perimetry in early glaucoma.

Methods

In this cross-sectional study, one eye from each of 96 healthy controls and 90 eyes with open-angle glaucoma were measured with cpRNFL, mGCL++, cpVD, mVD, Pulsar perimetry with Octopus P32 test (Pulsar) and standard perimetry with Humphrey field analyser 24-2 test (HFA). For direct comparison, all parameters were converted to relative change values adjusted in both their dynamic range and age-corrected normal value.

Results

The degree of loss in mGCL++ (−24.7%) and cpRNFL (−25.8%) was greater than that in mVD (−17.3%), cpVD (−14.9%), Pulsar (−10.1%) and HFA (−5.9%) (each p<0.01); the degree of loss in mVD and cpVD was greater than that in Pulsar and HFA (each p<0.01); and the degree of loss in Pulsar was greater than that in HFA (p<0.01). The discrimination ability between glaucomatous and healthy eyes (area under the curve) was higher for mGCL++ (0.90) and cpRNFL (0.93) than for mVD (0.78), cpVD (0.78), Pulsar (0.78) and HFA (0.79).

Conclusion

The degree of loss of cpRNFL and mGCL++ thickness preceded by approximately 7%–10% and 15%–20% compared with the micro-VD and visual fields in early glaucoma, respectively.

Trial registration number

UMIN Clinical Trials Registry (http://www.umin.ac.jp/; R000046076 UMIN000040372).

Chromatic visual evoked potentials identify optic nerve dysfunction in patients with Graves' orbitopathy

PURPOSE

To explore visual dysfunction in Graves' orbitopathy (GO) objectively by analyzing chromatic visual evoked potentials (cVEP) and evaluate its diagnostic efficiency for dysthyroid optic neuropathy (DON).

METHODS

In this cross-sectional study, we analyzed pattern-reversal VEP (pVEP), red-green (R-G) and blue-yellow (B-Y) cVEP in 93 subjects (21 with DON, Group A, 30 with GO, Group B, and 42 healthy controls, Group C) at Wuhan Union Hospital, China.

RESULTS

Compared with Group C, the amplitudes of B-Y cVEP were significantly lower in Group B, whereas all amplitudes of cVEP, latencies and amplitudes of pVEP in Group A were significantly impaired. In addition, the pVEP latency at 60 arcmin (60'), pVEP amplitudes and R-G cVEP amplitudes were significantly different between Group A and B. Moreover, 60'cVEP R-G negative-positive (N-P) amplitude was correlated with crowding index (P = 0.001), the average thickness of ganglion cell layer and inner plexiform layer (P = 0.004). Furthermore, combination of 60'cVEP R-G amplitude and 60'pVEP P100 latency had better diagnostic efficiency than each single parameter, with optimal cut-off values of 14.20 μV and 110.65 ms, respectively.

CONCLUSION

GO may induce electrophysiological changes. The presence of B-Y cVEP anomalies in moderate to severe GO patients may be an early sign of preclinical DON. A decline in 60'cVEP R-G amplitude is associated with apical crowding and thinner inner intra-retinal layers. The combination of 60'cVEP R-G N-P amplitude and 60'pVEP latency can be a useful diagnostic index for DON.

The “Topography” of Glaucomatous Defect Using OCT and Visual Field Examination

Aim

To describe the modifications in the superior and inferior retinal nerve fiber layer (RNFL) thickness regarding the distribution of the VF defects for the horizontal meridians in glaucomatous patients and the differences in the RNFL thickness topography between glaucomatous and healthy subjects.

Methods

One hundred twenty eyes of 91 patients affected by glaucoma and 94 eyes of 51 normal patients were retrospectively reviewed. Computerized 30°VF (Octopus G1 Dynamic strategy) and optical coherence tomography (OCT) ONH and 3D disk analysis were performed in all cases. The RNFL thickness measures analyzed in both groups were superior-nasal (SN), superior-temporal (ST), inferior-nasal (IN), and inferior temporal (IT) sectors. The VFs were classified according to the distribution of the VF defect as for the horizontal meridian in the pattern deviation plot as superior, inferior, predominantly superior, or predominantly inferior.

Result

In the glaucomatous group, 78 eyes (65%) showed a predominantly superior VF defect, while 38 eyes (32%) showed a predominantly inferior VF defect. Fifty-six eyes (46.7%) presented an exclusively superior, and 27/120 eyes (22.5%) presented an exclusively inferior VF defect. In the control group, the thickest RNFL sector was IT. The ST sector showed the thickest RNFL in presence of an exclusive superior VF defect. In case of an exclusive inferior VF defect, the thickest RNFL was the IT sector. VF showing superior defect presented a more altered MD than the VF with an inferior defect.

Conclusion

Glaucomatous damage affects both the superior and inferior neural rim almost simultaneously. However, the neural rim loss seems to be asymmetric, involving the inferior or superior rim depending on the predominant involvement of the superior or inferior hemifield at the VF test. Particularly, the IT sector appears to be the most compromised in glaucomatous eyes. Therefore, the asymmetry between superior and inferior RNFL could support the diagnosis of glaucoma.

How to cite this article

de Paula A, Perdicchi A, Pocobelli A, et al. The “Topography” of Glaucomatous Defect Using OCT and Visual Field Examination. J Curr Glaucoma Pract 2022;16(1):31-35.

Visual function tests for glaucoma practice - What is relevant?

Glaucoma represents one of the most important ocular diseases causing irreversible ganglion cell death. It is one of the most common causes of visual impairment and morbidity in the elderly population. There are various tests for measuring visual function in glaucoma. While visual field remains the undisputed method for screening, diagnosis, and monitoring disease progression, other tests have been studied for their utility in glaucoma practice. This review discusses some of the commonly used tests of visual function that can be routinely used in clinics for glaucoma management. Among the various modalities of testing visual function in glaucoma, this review highlights the tests that are most clinically relevant.

Evaluating multidisciplinary glaucoma care: visual field progression and loss of sight year analysis in the community vs hospital setting

BACKGROUND

A variety of shared care models have been developed, which aim to stratify glaucoma patients according to risk of disease progression. However, there is limited published data on the rate of glaucoma progression in the hospital vs community setting. Here we aimed to compare rates of glaucomatous visual field progression in the Cambridge Community Optometrist Glaucoma Scheme (COGS) and Addenbrooke's Hospital Glaucoma Clinic (AGC).

METHODS

A retrospective comparative cohort review was performed. Patients with five or more visual field tests were included. Zeiss Forum software was used to calculate the MD progression rate (dB/year). Loss of sight years (LSY) were also calculated for both COGS and AGC.

RESULTS

Overall, 8465 visual field tests from 854 patients were reviewed. In all, 362 eyes from the AGC group and 210 eyes from COGS were included. The MD deterioration rate was significantly lower in the COGS patients compared with the AGC group (-0.1 vs -0.3 dB/year; p < 0.0001). No patients in the COGS group were predicted to become blind within their lifetime by LSY analysis. Fifteen patients were at risk in the AGC group.

CONCLUSION

This service evaluation shows that COGS is an effective scheme to stratify lower risk glaucoma patients, increasing the capacity within hospital eye services. COGS patients have a lower rate of visual field deterioration compared to AGC patients. Effective communication between community and tertiary schemes is essential to facilitate transfer of patients requiring further hospital management reliably and efficiently, with the potential for low-risk patients to be followed safely in the community.

Abnormal perception of pattern-induced flicker colors in subjects with glaucoma

Pattern-induced flicker colors (PIFCs) are subjective colors that can be elicited with rotation of an achromatic stimulus such as the Benham disk. The perceptive mechanisms underlying PIFCs are not well-understood, but are thought to be generated primarily by retinal cell types which may be dysfunctional in glaucoma. Using a custom computer-based system, we tested PIFC perception across several Benham disk parameters, including the rates of acceleration and deceleration, rotational direction, and image contrast in both control and glaucoma subjects. We defined the Benham perception limit (BPL) during acceleration as the rotational speed at which PIFCs were first detected (Benham perception limit for acceleration) and the BPL during deceleration as the rotational speed at which PIFCs were extinguished (Benham perception limit for deceleration). In general, we found that glaucoma subjects perceived PIFCs less frequently than control subjects. For all subjects, we found that slower rates of acceleration and deceleration resulted in a lower Benham perception limit for acceleration and a higher Benham perception limit for deceleration, suggesting that PIFCs were both more easily detected and extinguished. Finally, subjects with glaucoma required increased rotational speeds during acceleration to detect PIFCs under certain conditions. Further study is needed to determine if these findings can be used to enhance clinical detection strategies.

Recent developments in perimetry: test stimuli and procedures

Automated perimetry has evolved substantially in recent years, in part due to modern computer technology that enables more complex visual stimuli and test procedures to be realised than those incorporated in traditional white-on-white luminance increment perimetry. This paper reviews briefly a number of advances in automated perimetry. The review includes discussion of new test types: frequency doubling technology perimetry, short wavelength automated perimetry, flicker perimetry, high-pass resolution perimetry and rarebit perimetry. Test algorithms applied to perimetry such as zippy estimation of sequential thresholds (ZEST), Swedish interactive thresholding algorithm (SITA), tendency-oriented perimetry (TOP) and multi-sampling supra-threshold perimetry are also discussed.

Comparison between blue-on-yellow and white-on-white perimetry in patients with branch retinal vein occlusion

This study aimed to compare blue-on-yellow (B/Y) perimetry with white-on-white (W/W) perimetry in eyes with branch retinal vein occlusion (BRVO). The following measurements were performed in 29 eyes of 29 patients with resolved BRVO: W/W and B/Y perimetries using 10-2 test grid, retinal volume (RV) using optical coherence tomography (OCT), and vessel densities (VD) of the superficial capillary layer (VDs) and deep capillary layer (VDd) using OCT angiography (OCTA). First, the difference in the retinal sensitivity (RS) between BRVO-affected and unaffected areas was compared between RS_B/Y and RS_W/W in the parafoveal and extrafoveal areas. Moreover, the structure–function relationship between vessel density and RS was compared between B/Y and W/W perimetries (RS_B/Y and RS_W/W, respectively). The difference in RS between BRVO-affected and unaffected areas was significantly larger with RS_B/Y than with RS_W/W in both the parafoveal and extrafoveal areas. In the parafoveal area, VDs, VDd, and RV were significantly correlated with both RS_W/W and RS_B/Y. In contrast, in the extrafoveal area, only VDd was included in the optimal models. Our findings suggest that RS_B/Y more strongly reflects the anatomical structure and BRVO-affected area.

Short wavelength automated perimetry and standard automated perimetry in central serous chorioretinopathy

Short wavelength automated perimetry (SWAP) is known for detecting the early reduction of retinal sensitivity (RS) in glaucoma. It’s application in retinal diseases have also been discussed previously. We investigated the difference in RS measured between standard white-on-white automated perimetry (WW) and blue-on-yellow SWAP in central serous chorioretinopathy (CSC). The overall RS (W-RS, S-RS) as well as the RS inside and outside of the serous retinal detachment (SRD) region were investigated in 26 eyes of 26 CSC patients using WW and SWAP. The central retinal thickness, central choroidal thickness, SRD area (SRDa), and SRD height at the fovea were measured using optic coherence tomography. RS inside the SRD region was lower than that of outside for both perimetries (both p < 0.001). The difference between RS inside and outside of the SRD region was greater in SWAP compared to WW (p < 0.001). Univariate analysis revealed significant correlations between SRDa and both W-RS and S-RS (both p < 0.001); moreover, multivariate analysis indicated that only S-RS was selected as the optimal model for SRDa. Our study demonstrated that SWAP was detected the decrease in RS more accurately than WW in CSC. These results may suggest the usefulness of SWAP for detecting change of retinal function in CSC.

Review of Longitudinal Glaucoma Progression: 5 Years after the Shaffer Lecture

In 2013, the senior author delivered the American Academy of Ophthalmology Robert N. Shaffer Lecture entitled "Glaucoma Changes-Reality Bites." This talk focused on describing the longitudinal structure-function relationships in glaucoma progression. The study was based on a 10-year longitudinal dataset created by calibrated measurements across multiple OCT generations with corresponding visual fields (VFs). The prior held observation was that functional damage follows structural damage. The lecture posited that structure and function change at similar times, but that current measurement technology limits our ability to detect functional abnormalities and change early in glaucoma, as well as to measure structural change late in the disease. The Shaffer lecture provided evidence that structure and function change concordantly and that any apparent discordance in the relationship was due to technologic limitations to measure glaucomatous change. Furthermore, we observed 5 longitudinal relationships of concordance and discordance that can exist with structure-function interactions. Concordance: (1) structure-structure progression, (2) structure-function tipping point, (3) structural floor tipping point. Discordance: (4) functional progression in a "stable" VF with structure-function correlation, (5) functional progression with "normal" structure. In this review article, we will review longitudinal glaucoma progression studies with long-term follow-up and discuss the clinical relevance of relationships of concordance and discordance that can exist with structure-function interactions.

Color visual acuity in preperimetric glaucoma and open-angle glaucoma

Purpose

To investigate the clinical significance of color visual acuity (CVA) in preperimetric glaucoma (PPG) and open-angle glaucoma (OAG).

Methods

A total of 123 eyes of 73 subjects (22 normal eyes, 14 PPG eyes, and 87 OAG eyes; mean age: 44.9 ± 10.1 years, age range: 21–64 years) were enrolled. CVA was tested for red, green-yellow, blue-green and blue-purple with a newly developed test.

Results

There was no statistical difference in clinical background factors, including age, sex, intraocular pressure, or spherical equivalent between the three groups. Red VA and blue-green VA were significantly worse in the OAG eyes than in the normal eyes (P = 0.008 and P = 0.015, respectively), although green-yellow VA and blue-purple VA were not significantly worse. Furthermore, red VA and blue-green VA were significantly correlated with MD in a group of eyes with either PPG or OAG (r = -0.23, P = 0.023; r = -0.25, P = 0.012, respectively), but green-yellow VA and blue-purple VA were not.

Conclusion

Red VA and blue-green VA were detectably worse in eyes with OAG, in close association with the degree of functional loss. This suggests that measuring CVA with the new color test described here may be a promising supplement to existing methods of detecting glaucoma and evaluating its severity.

Metamorphopsia Score and Central Visual Field Outcomes in Diabetic Cystoid Macular Edema

Aim

To detect abnormality of the visual function in naïve patients with cystoid diabetic macular edema (DME) using M-charts, Amsler test, and white on white (W/W) and blue on yellow (B/Y) perimetry.

Methods

There were 64 eyes included in the study: 30 eyes with DME, 22 eyes with diabetes without DME, and 12 eyes of normal subjects. Conventional W/W perimetry and B/Y perimetry were performed within the central 10° of the visual field. To assess metamorphopsia, Amsler test and M-charts were used.

Results

The rate of detection of metamorphopsia was 37% with Amsler test examination and 50% with M-charts. Specificity of both tests was 100%. We found a significant difference between vertical scores of M-charts in all groups, but not in horizontal scores (p < 0.0001). Mean defect (MD) was 8.9 dB and 3.6 dB and loss variance (LV) 4.8 dB and 3.3 dB (p < 0.0001).

Conclusions

M-chart is more sensitive than Amsler test method for detection of metamorphopsia. The MD and LV are higher in b/y in comparison to W/W perimetry. B/Y perimetry and M-charts are more sensitive than conventional methods for detecting the visual function loss in cystoid DME.

Conventional Perimetry, Short-Wavelength Automated Perimetry, Frequency-Doubling Technology, and Visual Evoked Potentials in the Assessment of Patients with Multiple Sclerosis

PURPOSE

To evaluate the diagnostic power of conventional, achromatic, automated perimetry (CAP), short-wavelength automated perimetry (SWAP), frequency-doubling technology (FDT) perimetry, and visual evoked potentials (VEP) in a group of patients with multiple sclerosis (MS) with or without a history of optic neuritis.

METHODS

Thirty eyes of 15 patients (5 male, 10 female, average age 38+/-7 years) with confirmed diagnosis of MS underwent CAP, SWAP (Humphrey 750-II VFA, program central 30-2, full-threshold strategy), FDT perimetry (program N-30), and pattern VEPs. Sixteen eyes (53.3%) had no history of ocular involvement and a negative ophthalmologic examination. They were matched with a control group of 10 healthy volunteers (4 male, 6 female, average age 31+/-10 years). The mean deviation (MD) and the pattern standard deviation (PSD) of the two groups were compared (t-test). Fourteen eyes (46.7%) had, on the contrary, a history of optic neuritis. Inside this group, the MD and the PSD of the three techniques were correlated (Spearman's rank test), in order to investigate whether any significant differences might be revealed by these techniques in pointing out the total amount of visual field damage.

RESULTS

When comparing MS patients without signs or symptoms of ocular involvement and a control group, no significant differences were found for CAP MD, CAP PSD, and FDT PSD. Significant differences were found, on the contrary, for SWAP MD (p=0.0014), SWAP PSD (p=0.0001), and FDT MD (p=0.0001). When considering the MD and the PSD of the three techniques in the group of MS patients who had a history of optic neuritis, a significant correlation was found only between CAP MD and SWAP MD (r=0.0057), with a tendency by SWAP to reveal a higher rate of visual field loss. The other correlations were not significant. According to predefined criteria, the group of asymptomatic subjects had abnormal CAP in 1 eye (6.25%), abnormal SWAP in 9 (56.2%), abnormal FDT in 11 (68.7%), and abnormal VEPs in 7 (43.7%). The combined use of all techniques allowed us to identify silent optic nerve impairment in 15 (93.7%) eyes.

CONCLUSIONS

Short-wavelength automated perimetry and FDT perimetry are two non-conventional perimetric techniques that were mainly developed for the early detection of glaucomatous damage. The results of this study demonstrate their efficacy also in detecting early visual field deficits in MS patients without clinical signs of optic neuropathy. Frequency doubling perimetry, in particular, proved to be an easy, fast, and sensitive technique in the assessment of patients with MS. Our results also suggest that subclinical visual involvement in MS can be better diagnosed using multiple (neurophysiologic and psychophysical) tests.

The diagnostic use of choroidal thickness analysis and its correlation with visual field indices in glaucoma using spectral domain optical coherence tomography

PURPOSE

To evaluate the quantitative characteristics of choroidal thickness in primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) and in normal eyes using spectral-domain optical coherence tomography (SD-OCT). To evaluate the diagnostic ability of choroidal thickness in glaucoma and to determine the correlation between choroidal thickness and visual field parameters in glaucoma.

METHODS

A total of 116 subjects including 40 POAG, 30 NTG and 46 healthy subjects were enrolled in this study. Choroidal thickness measurements were acquired in the macular and peripapillary regions using SD-OCT. All subjects underwent white-on-white (W/W) and blue-on-yellow (B/Y) visual field tests using Humphrey Field Analyzer. The receiver operating characteristic (ROC) curve and the area under curve (AUC) were generated to assess the discriminating power of choroidal thickness for glaucoma. Pearson's correlation coefficients were calculated to assess the structure function correlation for glaucoma patients.

RESULTS

No significant differences were observed for macular choroidal thickness among the different groups (all P > 0.05). Regarding the peripapillary choroidal thickness (PPCT), significant differences were observed among the three groups (all P < 0.05). Post hoc tests for multiple comparisons revealed a significant difference in the NTG-normal comparison group (all P < 0.01). The inferior and temporal PPCT in POAG patients were significantly thinner than those in normal subjects (P = 0.007, P = 0.002, respectively). Different parameters of PPCT showed significantly low diagnostic values to detect POAG from normal subjects (AUC: 0.555 to 0.652) and to discriminate NTG from POAG (AUC: 0.462 to 0.702), but moderate diagnostic power to detect NTG from normal subjects (AUC: 0.708 to 0.771). Regarding the diagnosis of early glaucoma, different parameters of PPCT showed relatively low diagnostic power (AUC: 0.606 to 0.698). In all the glaucoma subjects, PPCT was not significantly correlated with W/W mean deviation (MD) (all P > 0.05), but showed significant correlations with B/Y MD (all P < 0.05). In the early glaucomatous eyes, PPCT showed significant correlations with W/W MD and B/Y MD (all P < 0.05).

CONCLUSIONS

In our study, peripapillary choroidal thickness measured on OCT showed a low to moderate but statistically significant diagnostic power and a significant correlation with blue-on-yellow visual field indices in glaucoma. This may indicate a potential adjunct for peripapillary choroidal thickness in glaucoma diagnosis.

Test Conditions in Macular Visual Field Testing in Glaucoma

PURPOSE

The purpose of this study is to evaluate the suitable visual field (VF) test conditions (target size, test type, and eccentricity) for the macular region, we investigated the correlations between the ganglion cell layer (GCL) thickness and 6 VF test results.

METHODS

We tested 32 eyes of patients (61.1±9.2 y) with preperimetric (6), early-stage (16), and moderate-stage (10) glaucoma. The VF tests included 3 SAP (the 10-2 HFA using SITA with target size III [HFA SITA (III)], full threshold with size III [HFA FULL (III)] and size I [HFA FULL (I)]) and 3 visual function-specific perimetry tests (the 10-2 SWAP, 10-2 flicker, and 10-2 Humphrey Matrix). The GCL and inner plexiform layer (GCL+IPL) thickness was measured by Spectral Domain Optical Coherence Tomography (SD-OCT) with a macular 7×7 mm cube scan (3D OCT-2000, Topcon). The coefficient of determination (r) for the correlation between visual sensitivity and the GCL+IPL thickness was calculated for each test at eccentricities 0 to 5 degrees, 5 to 7 degrees, and 7 to 10 degrees using linear and quadratic regressions.

RESULTS

All 6 tests showed the strongest correlation with the GCL+IPL thickness at 5 to 7 degrees. The respective r (linear) and R (quadratic) for HFA SITA (III), HFA FULL (III), HFA FULL (I), SWAP, Flicker, and Matrix were (0.40, 0.50), (0.43, 0.53), (0.44, 0.46), (0.51, 0.51), (0.33, 0.34), and (0.52, 0.52).

CONCLUSIONS

As compared with the frequently-used SAP with a size III, SAP with size I and the function-specific perimetry tests (especially the Matrix) could be more suitable for testing the macular region.

The Relation of White-on-White Standard Automated Perimetry, Short Wavelength Perimetry, and Optic Coherence Tomography Parameters in Ocular Hypertension

PURPOSE

The purpose of this study is to examine the demographics, clinical properties, and the relation between white-on-white standard automated perimetry (SAP), short wavelength automated perimetry (SWAP), and optical coherence tomographic (OCT) parameters of patients with ocular hypertension.

MATERIALS AND METHODS

Sixty-one eyes of 61 patients diagnosed with ocular hypertension in the Ankara Numune Education and Research Hospital ophthalmology unit between January 2010 and January 2011 were included in this study. All patients underwent SAP and SWAP tests with the Humphrey visual field analyser using the 30.2 full-threshold test. Retinal nerve fiber layers (RNFL) and optic nerve heads of patients were evaluated with Stratus OCT.

RESULTS

Positive correlation was detected between SAP pattern standard deviation value and average intraocular pressure (P=0.017), maximum intraocular pressure (P=0.009), and vertical cup to disc (C/D) ratio (P=0.009). Positive correlation between SWAP median deviation value with inferior (P=0.032), nasal (P=0.005), 6 o'clock quadrant RNFL thickness (P=0.028), and Imax/Tavg ratio (P=0.023) and negative correlation with Smax/Navg ratio (P=0.005) were detected. There was no correlation between central corneal thickness and peripapillary RNFL thicknesses (P>0.05).

CONCLUSIONS

There was no relation between SAP median deviation, pattern standard deviation values and RNFL thicknesses and optic disc parameters of the OCT. By contrast significant correlation between several SWAP parameters and OCT parameters were detected. SWAP appeared to outperform achromatic SAP when the same 30-2 method was used.

Primary open-angle glaucoma

Glaucoma is an optic neuropathy that is characterized by the progressive degeneration of the optic nerve, leading to visual impairment. Glaucoma is the main cause of irreversible blindness worldwide, but typically remains asymptomatic until very severe. Open-angle glaucoma comprises the majority of cases in the United States and western Europe, of which, primary open-angle glaucoma (POAG) is the most common type. By contrast, in China and other Asian countries, angle-closure glaucoma is highly prevalent. These two types of glaucoma are characterized based on the anatomic configuration of the aqueous humour outflow pathway. The pathophysiology of POAG is not well understood, but it is an optic neuropathy that is thought to be associated with intraocular pressure (IOP)-related damage to the optic nerve head and resultant loss of retinal ganglion cells (RGCs). POAG is generally diagnosed during routine eye examination, which includes fundoscopic evaluation and visual field assessment (using perimetry). An increase in IOP, measured by tonometry, is not essential for diagnosis. Management of POAG includes topical drug therapies and surgery to reduce IOP, although new therapies targeting neuroprotection of RGCs and axonal regeneration are under development.

Baseline factors predicting the risk of conversion from ocular hypertension to primary open-angle glaucoma during a 10-year follow-up

PurposeTo evaluate the ability of baseline clinical, morphological, and functional factors to predict the conversion to primary open-angle glaucoma (POAG) in ocular hypertensive (OHT) patients.MethodsThis single-center prospective longitudinal observational study included 116 eyes of 116 OHT patients followed for a 10-year period. All patients had intraocular pressure (IOP) ≥24 mm Hg in one eye and >21 mm Hg in the other eye, normal visual fields (VFs) and normal optic disc (OD) appearance in both eyes at baseline. All OHT patients were untreated at baseline with subsequent treatment upon need according to clinical judgement. Only one eye per subject was randomly selected. Patient age, gender, IOP, central corneal thickness (CCT), and ibopamine test results were collected at baseline. All patients underwent standard automated perimetry, short-wavelength automated perimetry (SWAP), frequency-doubling technology, confocal scanning laser ophthalmoscopy (CSLO), and scanning laser polarimetry (SLP) at baseline and every 6 months thereafter. Main outcome measure was the conversion to POAG, defined as the development of reproducible VF and/or OD abnormalities attributable to glaucoma. Cox proportional hazards models were used to identify the baseline factors predictive of POAG conversion.ResultsDuring the 10-year follow-up, 25% of eyes converted to POAG. In multivariate Cox models, baseline factors that were significant predictors of POAG development included: older age (hazard ratio (HR) 1.0, 99% confidence intervals (CIs) 1.0-1.2, per 1 year older); SWAP Glaucoma Hemifield test 'outside normal limits' (HR 4.3, 99% CIs 1.2-17.9); greater SLP 'Inter-eye Symmetry' (HR 1.1, 99% CIs 0.4-3.0, per 1 unit lower); lower CSLO Rim Volume (HR 1.1, 99% CIs 0.3-3.2, per 0.1 mm(3) lower); and greater CSLO cup-to-disc ratio (HR 6.0, 99% CIs 3.6-16.8, per 0.1 unit greater).ConclusionsThe baseline parameters that proved to be useful in assessing the likelihood of an OHT patient to develop POAG included age, functional variables provided by SWAP, and structural variables provided by SLP and CSLO. In this cohort of patients, baseline IOP, CCT, and ibopamine provocative test results were not significant predictors of POAG conversion.

Crowding in the S-cone pathway

The spatial extent of interference from nearby object or contours (the critical spacing of "crowding") has been thoroughly characterized across the visual field, typically using high contrast achromatic stimuli. However, attempts to link this measure with known properties of physiological pathways have been inconclusive. The S-cone pathway, with its ease of psychophysical isolation and known anatomical characteristics, offers a unique tool to gain additional insights into crowding. In this study, we measured the spatial extent of crowding in the S-cone pathway at several retinal locations using a chromatic adaptation paradigm. S-cone crowding was evident and extensive, but its spatial extent changed less markedly as a function of retinal eccentricity than the extent found using traditional achromatic stimuli. However, the spatial extent agreed with that of low contrast achromatic stimuli matched for isolated resolvability. This suggests that common cortical mechanisms mediate the crowding effect in the S-cone and achromatic pathway, but contrast is an important factor. The low contrast of S-cone stimuli makes S-cone vision more acuity-limited than crowding-limited.

Short-Wavelength Automated Perimetry Parameters at Baseline and Following Remission in Patients With Birdshot Retinochoroidopathy

PURPOSE

To identify changes in short-wavelength automated perimetry patterns and parameters between the active and inactive states.

DESIGN

Retrospective cohort study with age-matched, normal controls.

METHODS

setting: Private tertiary referral center.

STUDY POPULATION

Seventy-five eyes of 38 patients with active birdshot retinochoroidopathy and 37 eyes of 37 historical normal controls.

INTERVENTION

Thirty-seven patients received immunomodulatory therapy. A fluocinolone acetonide intravitreal implant (Retisert) was implanted in both eyes of 1 patient as an initial treatment.

MAIN OUTCOME MEASURES

Changes in short-wavelength automated perimetry total deviation scores, pattern deviation scores, mean deviation, and pattern standard deviation in the active phase and the remission state.

RESULTS

Mean deviation (P = .006), pattern standard deviation (P = .001), total deviation score (P = .002), and pattern deviation score (P = .007) were significantly different from the active phase to the remission state. The length of time required to achieve remission did not significantly affect the changes in mean deviation (regression coefficient = 0.01; P = .92), pattern standard deviation (regression coefficient = 0.01; P = .87), total deviation score (regression coefficient = -0.1; P = .32), or pattern deviation score (regression coefficient = 0.1; P = .36) from the active phase to the remission state.

CONCLUSION

There was significant improvement in total deviation score, pattern deviation score, mean deviation, and pattern standard deviation on short-wavelength automated perimetry as patients achieved remission. Short-wavelength automated perimetry appears to be a useful and complementary modality in monitoring disease activity in birdshot retinochoroidopathy.

Comparison of Standard Automated Perimetry, Short-Wavelength Automated Perimetry, and Frequency-Doubling Technology Perimetry to Monitor Glaucoma Progression

Detection of progression is paramount to the clinical management of glaucoma. Our goal is to compare the performance of standard automated perimetry (SAP), short-wavelength automated perimetry (SWAP), and frequency-doubling technology (FDT) perimetry in monitoring glaucoma progression.Longitudinal data of paired SAP, SWAP, and FDT from 113 eyes with primary open-angle glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. Data from all tests were expressed in comparable units by converting the sensitivity from decibels to unitless contrast sensitivity and by expressing sensitivity values in percent of mean normal based on an independent dataset of 207 healthy eyes with aging deterioration taken into consideration. Pointwise linear regression analysis was performed and 3 criteria (conservative, moderate, and liberal) were used to define progression and improvement. Global mean sensitivity (MS) was fitted with linear mixed models.No statistically significant difference in the proportion of progressing and improving eyes was observed across tests using the conservative criterion. Fewer eyes showed improvement on SAP compared to SWAP and FDT using the moderate criterion; and FDT detected less progressing eyes than SAP and SWAP using the liberal criterion. The agreement between these test types was poor. The linear mixed model showed a progressing trend of global MS overtime for SAP and SWAP, but not for FDT. The baseline estimate of SWAP MS was significantly lower than SAP MS by 21.59% of mean normal. FDT showed comparable estimation of baseline MS with SAP.SWAP and FDT do not appear to have significant benefits over SAP in monitoring glaucoma progression. SAP, SWAP, and FDT may, however, detect progression in different glaucoma eyes.

Significance of the disc damage likelihood scale objectively measured by a non-mydriatic fundus camera in preperimetric glaucoma

Purpose

To assess the correlation between the disc damage likelihood scale (DDLS) objectively measured by a non-mydriatic fundus camera, Heidelberg Retina Tomograph 3, and optic coherence tomography in preperimetric glaucoma.

Methods

One-hundred-twenty-five patients with preperimetric primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (n=30) were included (mean age 58.9±15.9 years). All three devices graded the optic disc topography: Diagnosis 1 was defined as “outside normal limits”, while Diagnosis 2 as “borderline or outside normal limits”.

Results

For Diagnosis 1, a significant correlation was shown between DDLS and Moorfields regression analysis (P=0.022), and for Diagnosis 2 with glaucoma probability score analysis (P=0.024), in POAG. In pseudoexfoliation glaucoma, DDLS did not correlate significantly with Heidelberg Retina Tomograph 3 and optic coherence tomography. Regarding the area under the curve the highest predictive power was demonstrated by the objective DDLS (0.513–0.824) compared to Burk (0.239–0.343) and Mikelberg (0.093–0.270) coefficients.

Conclusions

The DDLS showed a significant correlation to the Moorfields regression analysis in preperimetric POAG. The objective DDLS showed the highest predictive power and thus is an additive tool in diagnosing preperimetric glaucoma.

Short wavelength automated perimetry can detect visual field changes in diabetic patients without retinopathy

Purpose:

The purpose of the following study is to compare short wave automated perimetry (SWAP) versus standard automated perimetry (SAP) for early detection of diabetic retinopathy (DR).

Materials and Methods:

A total of 40 diabetic patients, divided into group I without DR (20 patients = 40 eyes) and group II with mild non-proliferative DR (20 patients = 40 eyes) were included. They were tested with central 24-2 threshold test with both shortwave and SAP to compare sensitivity values and local visual field indices in both of them. A total of 20 healthy age and gender matched subjects were assessed as a control group.

Results:

Control group showed no differences between SWAP and SAP regarding mean deviation (MD), corrected pattern standard deviation (CPSD) or short fluctuations (SF). In group I, MD showed significant more deflection in SWAP (−4.44 ± 2.02 dB) compared to SAP (−0.96 ± 1.81 dB) (P =0.000002). However, CPSD and SF were not different between SWAP and SAP. In group II, MD and SF showed significantly different values in SWAP (−5.75 ± 3.11 dB and 2.0 ± 0.95) compared to SAP (−3.91 ± 2.87 dB and 2.86 ± 1.23) (P =0.01 and 0.006 respectively). There are no differences regarding CPSD between SWAP and SAP. The SWAP technique was significantly more sensitive than SAP in patients without retinopathy (p), but no difference exists between the two techniques in patients with non-proliferative DR.

Conclusion:

The SWAP technique has a higher yield and efficacy to pick up abnormal findings in diabetic patients without overt retinopathy rather than patients with clinical retinopathy.

Blue-yellow and standard pattern visual evoked potentials in phakic and pseudophakic glaucoma patients and controls

PURPOSE

Blue-yellow short wavelength testing (BY-VEPs) has proven diagnostic relevance in detecting early ganglion cell damage, e.g., in glaucoma. To date testing has generally been conducted using individual protocols without consideration of the lens status. In this study, we compared changes in BY-VEPs and standard pattern VEPs in phakic and pseudophakic glaucoma patients and controls.

METHODS

The eyes of 57 healthy controls (18 pseudophakic and 39 phakic) and 67 glaucoma patients (29 pseudophakic and 38 phakic) were included in a prospective study. Phakic eyes were arranged in three groups according to the Lens Opacities Classification System III. Transient on/off isoluminant blue-yellow 2° checks were used for BY-VEPs, transient large 1° (M1) and small 0.25° (M2) black-white checks for standard pattern reversal VEPs, according to the ISCEV standards.

RESULTS

Latencies and amplitudes of M1 and M2 did not differ significantly between groups or lens status. ANOVA analysis revealed significantly longer BY-VEP latencies in glaucoma compared to controls (p = 0.002), independently of the lens status. The amplitudes showed no such pattern (p = 0.93). Mean defect (MD) was significantly negatively correlated to BY-VEP latency (r = -0.54, p = 0.003) only in pseudophakic glaucoma patients. Different stages of cataract did not show a significant effect on the BY-VEP latencies.

CONCLUSIONS

Glaucoma led to a significant increase of BY-VEPs latencies, while standard pattern VEPs were not influenced. The correlation of MD and BY-VEP latency only in pseudophakic glaucoma patients indicates a substantial confounding effect of lens opacifications on the diagnostic value of BY-VEPs in glaucoma.

Flicker defined form, standard perimetry and Heidelberg retinal tomography: Structure-function relationships

OBJECTIVE

To compare flicker defined form (FDF) perimetry using the Heidelberg edge perimeter (HEP) with standard automated perimetry (SAP) on the Humphrey visual field (HVF) analyzer and to compare their relationship to structural measurements acquired with the Heidelberg retina tomograph.

DESIGN

Prospective, observational study.

PARTICIPANTS

Thirty-one glaucomatous eyes with varying severity and 13 normal control eyes were included in this analysis.

METHODS

All subjects underwent FDF testing on the HEP using the 24-2 protocol by the adaptive staircase thresholding algorithm standard strategy and SAP on the HVF analyzer 750 II using the SITA-Standard 24-2 test. Heidelberg retina tomography (HRT) testing was obtained for each patient. Spearman correlation coefficient, mean deviation (MD), and pattern standard deviation measurements by both machines were compared.

RESULTS

FDF and SAP MD were significantly correlated (r = 0.81, p < 0.001). FDF and SAP MD were significantly correlated with HRT cup/disc ratio (FDF MD: p < 0.001; SAP MD: p = 0.003), disc area (FDF MD: p = 0.005; SAP MD: p = 0.059), rim volume (FDF MD: p < 0.001; SAP MD: p < 0.001), and retinal nerve fibre layer (FDF MD: p < 0.001; SAP MD: p < 0.001).

CONCLUSIONS

This pilot study shows that the MD parameter of FDF correlated with SAP results. FDF and SAP had significant correlations with HRT parameters in glaucomatous and healthy eyes. The potential utility of FDF in the clinical management of glaucoma requires further investigation.

How to detect progression in glaucoma

Detecting glaucoma progression remains one of the most challenging aspects of glaucoma management, since it can be hard to distinguish disease progression from exam variability and changes due to aging. In this review article, we discuss the use of perimetry, confocal scanning laser tomography and optical coherence tomography to detect glaucoma progression, and the techniques available to evaluate change with these modalities. Currently, there is no consensus on the best technique or criteria to detect glaucoma progression, or what amount of change would be clinically meaningful. New techniques have been developed to assess glaucoma progression, which make more comprehensive and complex use of data. They have the potential of detecting progression with better accuracy, with shorter follow-up periods, and generating better prognostics. Further validation of these new techniques is still required, but their incorporation into clinical practice is likely to yield significant benefits.

Selecting visual field tests and assessing visual field deterioration in glaucoma

Testing the peripheral field of vision is the mainstay for detection of glaucoma deterioration. Various methods and algorithms are currently available for detection of early glaucoma or establishing disease progression. Alternative testing strategies such as frequency doubling technology perimetry or short-wavelength automated perimetry have been extensively explored over the last 2 decades. The former has been found most promising for detection of earliest evidence of functional glaucoma damage when the standard achromatic perimetry results are still within the normal range. However, standard achromatic perimetry remains the standard technique for establishing deterioration of the disease. Both trend and event analyses are used for establishing change within series of visual fields. Trend analyses provide the clinician with rates of progression, putting the speed of glaucoma progression in the context of patient longevity, whereas event analyses demonstrate a "step" change regardless of the length of time it took for this amount of change to occur. The two techniques are complementary and should be used concurrently.

Ocular hypertension: an approach to assessment and management

Ocular hypertension is a common and important problem seen by eye care providers. This review presents a practical approach to individuals with ocular hypertension. It describes the common functional and structural investigations used in evaluation, as well as the advantages and disadvantages of each test. This review also discusses several landmark studies on ocular hypertension and provides a practical guide to the management of this problem.

Effect of yellow-tinted intraocular lens on standard automated perimetry and short wavelength automated perimetry in patients with glaucoma

Purpose:

To investigate the effect of cataract surgery and yellow-tinted intraocular lens (IOLs) implantation on perimetry indices of short-wavelength automated perimetry (SWAP) and standard automated perimetry (SAP) testing in patients with coexisting cataract and glaucoma.

Materials and Methods:

In this prospective comparative case series, phacoemulsification with implantation of yellow-tinted Acrysof Natural IOL was performed in 16 eyes of 16 patients with visually significant cataract (best-corrected visual acuity (VA) better than 20/120) and mild to moderate glaucoma. Pre- and postoperative values for VA and for perimetry indices including mean deviation (MD), pattern standard deviation (PSD), and foveal threshold (FT) from both SAP and SWAP testing were compared.

Results:

Postoperative VA improved significantly after cataract surgery and yellow-tinted IOL implantation (P < 0.001). After cataract extraction and IOL implantation, MD and FT on SWAP testing improved significantly (P = 0.001); however, there was no statistically significant change with SAP testing between the pre- and postoperative perimetry indices. There was no statistically significant change in PSD with either SAP or SWAP testing postoperatively. The differences between pre- and postoperative values for all perimetry indices under study were not significant when comparing SAP with SWAP tests, except for MD which had improved statistically significantly in SWAP testing (P = 0.03).

Conclusions:

In mild to moderate glaucoma patients with cataracts, the perimetry indices of SWAP testing improved after phacoemulsification and yellow-tinted IOL implantation. This suggests that the yellow-tinted IOLs have less effect on SWAP testing than visually significant cataracts.

The effect of cataract surgery on blue-yellow and standard-pattern visual-evoked potentials

PURPOSE

Blue-yellow visual-evoked potentials (BY-VEPs) may be used for diagnostics of functional ganglion cell damage in glaucoma and other ocular diseases. In this study we investigated the impact of lenticular opacities on BY- and standard pattern reversal VEPs by examining patients before and after cataract surgery.

METHODS

Eighteen patients with moderate cataract were included in a prospective study. Transient on/off isoluminant blue-yellow 2° checks were used for short-wavelength stimulation (BY-VEP), transient large 1° (M1) and small 0.25° (M2) black-white checks for standard pattern reversal VEPs. VEPs were acquired before (24 ± 30 days) and after cataract surgery (14 ± 16 days). The contralateral eye was used as a control.

RESULTS

Amplitude and latency of M1 and M2 peaks did not change significantly from before to after surgery. The amplitude of the BY-VEPs did not change significantly after cataract surgery (pre-surgery, -7.42 ± 3.43 μV, post-surgery, -7.93 ± 3.65 μV, p = 0.42), yet the latency of the main negative peak showed a significant decrease (pre-surgery, 143.9 ± 12.9 ms, post-surgery, 133.2 ± 7.7 ms, p = 0.0006). The BCVA improvement was significant from before to after cataract surgery (pre-surgery, 0.344 ± 0.125 LogMAR, post-surgery, 0.224 ± 0.179 LogMAR, p = 0.013) yet not correlated to the absolute decrease in latency of the BY-VEP after surgery (r = 0.309, p = 0.22). No significant changes were found in the contralateral eye.

CONCLUSIONS

The BY-VEP is sensitive to lenticular opacities of the human lens, presumably due to the increased short-wavelength absorption in the aging eye. This fact should be considered when applying BY-VEPs for diagnostics.

Strategies for improving early detection of glaucoma: the combined structure-function index

The early detection of glaucoma is important in order to enable appropriate monitoring and treatment, and to minimize the risk of irreversible visual field loss. Although advances in ocular imaging offer the potential for earlier diagnosis, the best method is likely to involve a combination of information from structural and functional tests. Recent studies have shown it is possible to estimate the number of retinal ganglion cells from optical coherence tomography and standard automated perimetry, and to then pool the results to produce a combined structure-function index (CSFI). The CSFI represents the estimated percentage of retinal ganglion cells lost compared to an age-matched healthy eye. Previous studies have suggested that the CSFI is better able to detect glaucoma than isolated measures of structure and function, and that it performs well even in preperimetric glaucoma. The purpose of this review is to describe new strategies, such as the CSFI, that have the potential to improve the early detection of glaucoma. We also describe how our ability to detect early glaucoma may be further enhanced by incorporating demographic risk factors, clinical examination findings, and imaging and functional test results into intuitive models that provide estimates of disease probability.

Development and validation of an associative model for the detection of glaucoma using pupillography

PURPOSE

To develop and validate an associative model using pupillography that best discriminates those with and without glaucoma.

DESIGN

A prospective case-control study.

METHODS

We enrolled 148 patients with glaucoma (mean age 67 ± 11) and 71 controls (mean age 60 ± 10) in a clinical setting. This prototype pupillometer is designed to record and analyze pupillary responses at multiple, controlled stimulus intensities while using varied stimulus patterns and colors. We evaluated three approaches: (1) comparing the responses between the two eyes; (2) comparing responses to stimuli between the superonasal and inferonasal fields within each eye; and (3) calculating the absolute pupil response of each individual eye. Associative models were developed using stepwise regression or forward selection with Akaike information criterion and validated by fivefold cross-validation. We assessed the associative model using sensitivity, specificity and the area-under-the-receiver operating characteristic curve.

RESULTS

Persons with glaucoma had more asymmetric pupil responses in the two eyes (P < 0.001); between superonasal and inferonasal visual field within the same eye (P = 0.014); and smaller amplitudes, slower velocities and longer latencies of pupil responses compared to controls (all P < 0.001). A model including age and these three components resulted in an area-under-the-receiver operating characteristic curve of 0.87 (95% CI 0.83 to 0.92) with 80% sensitivity and specificity in detecting glaucoma. This result remained robust after cross-validation.

CONCLUSIONS

Using pupillography, we were able to discriminate among persons with glaucoma and those with normal eye examinations. With refinement, pupil testing may provide a simple approach for glaucoma screening.

[Sensitivity and specificity of flicker perimetry with Pulsar. Comparison with achromatic (white-on-white) perimetry in glaucoma patients]

The early detection of functional glaucoma damage plays an increasingly more central role in the diagnosis and treatment of glaucoma disease. Using selective perimetry detection of early glaucomatous defects is more likely and one of these methods is flicker perimetry with Pulsar. Flicker perimetry is used to analyze the temporal visual function in combination with spatial resolution and contrast sensitivity as opposed to standard automated perimetry which measures the differential light sensitivity with a non-specific stimulus. This study showed a higher sensitivity and specificity of Pulsar perimetry in comparison to achromatic perimetry in glaucoma patients.

Heidelberg edge perimetry for the detection of early glaucomatous damage: a case report

PURPOSE

To illustrate the potential role for Heidelberg edge perimetry (HEP) in the assessment of early functional loss in glaucoma.

CASE REPORT

A 46-year-old male presented with raised intraocular pressure but healthy optic discs and normal standard automated perimetry (SAP). He was diagnosed with ocular hypertension, but after 16 years, he developed glaucomatous changes to the right optic disc and inferior retinal nerve fiber layer thinning. Despite the evidence of progressive structural damage, functional testing using SAP was repeatedly normal, based on conventional criteria. HEP, on the other hand, revealed an extensive superior visual field damage in agreement with the structural changes. Additionally, and in contrast to SAP, the HEP indices of Glaucoma Hemifield Test, mean deviation and pattern standard deviation were all outside normal limits.

CONCLUSION

This case illustrates that HEP may have an important role in the early detection of functional damage in glaucoma, with potential advantages over SAP.

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.

Comparison of Heidelberg retina tomography, optical coherence tomography and Humphrey visual field in early glaucoma diagnosis

OBJECTIVE

To determine the value of optic disc parameters and perimetric defects in the early diagnosis of patients with primary open-angle glaucoma (POAG).

METHODS

Optic disc parameters and perimetry were compared among patients in the early stage of POAG, patients with suspected POAG and healthy control subjects, using Heidelberg retina tomography (HRT-II), optical coherence tomography (OCT) and a Humphrey 750i automatic field analyser, in order to determine whether these parameters could be used for early POAG diagnosis.

RESULTS

A total of 55 participants were enrolled in the study. Significant differences in the optic disc parameter and perimetry values were observed between the three groups. HRT-II parameters showed good correlation with OCT parameters. The majority of the HRT-II and OCT parameters showed a good correlation with perimetry values.

CONCLUSIONS

HRT-II and OCT optic disc parameters both reflect morphological changes of the optic disc. These current findings suggest that they can both detect glaucomatous optic neuropathy earlier than a white-on-white perimetry examination. In addition, OCT can detect optic disc parameter changes that cannot be detected by HRT-II.

Retrobulbar blood flow and visual field alterations after acute ethanol ingestion

BACKGROUND

The purpose of this study was to test the effect of ethyl alcohol on the koniocellular and magnocellular pathway of visual function and to investigate the relationship between such visual field changes and retrobulbar blood flow in healthy subjects.

METHODS

In 12 healthy subjects (mean age 32 ± 4 years), color Doppler imaging, short-wavelength automated perimetry, and frequency doubling perimetry was performed before and 60 minutes after oral intake of 80 mL of 40 vol% ethanol. Mean and pattern standard deviations for short-wavelength automated and frequency doubling perimetry were assessed. End diastolic velocity (EDV) and peak systolic velocity (PSV) were measured in the central retinal and ophthalmic arteries using color Doppler imaging. Systemic blood pressure, heart rate, intraocular pressure, and blood alcohol concentration were determined.

RESULTS

Mean PSV and EDV in the central retinal artery showed a significant increase after alcohol intake (P = 0.03 and P = 0.02, respectively). Similarly, we found a significant acceleration of blood flow velocity in the ophthalmic artery (P = 0.02 for PSV; P = 0.04 for EDV). Mean intraocular pressure decreased by 1.0 mmHg after alcohol ingestion (P = 0.01). Retinal sensitivity in short-wavelength automated perimetry did not alter, whereas in frequency doubling perimetry, the mean deviation decreased significantly. Systolic and diastolic blood pressure did not change significantly. Mean blood alcohol concentration was 0.38 ± 0.16 g/L.

CONCLUSION

Although ethanol is known to cause peripheral vasodilation, our subjects had no significant drop in systemic blood pressure. However, a significant increase of blood flow velocity was seen in the retrobulbar vessels. Regarding visual function, moderate alcohol consumption led to reduced performance in the magnocellular visual system tested by frequency doubling perimetry, but had no effect on short-wavelength automated perimetry.

Assessment of novel binocular colour, motion and contrast tests in glaucoma

The effects of glaucoma on binocular visual sensitivity for the detection of various stimulus attributes are investigated at the fovea and in four paracentral retinal regions. The study employed a number of visual stimuli designed to isolate the processing of various stimulus attributes. We measured absolute contrast detection thresholds and functional contrast sensitivity by using Landolt ring stimuli. This psychophysical Landolt C-based contrast test of detection and gap discrimination allowed us to test parafoveally at 6 ° from fixation and foveally by employing interleaved testing locations. First-order motion perception was examined by using moving stimuli embedded in static luminance contrast noise. Red/green (RG) and yellow/blue (YB) colour thresholds were measured with the Colour Assessment and Diagnosis (CAD) test, which utilises random dynamic luminance contrast noise (± 45 %) to ensure that only colour and not luminance signals are available for target detection. Subjects were normal controls (n = 65) and glaucoma patients with binocular visual field defects (n = 15) classified based on their Humphrey Field Analyzer mean deviation (MD) scores. The impairment of visual function varied depending on the stimulus attribute and location tested. Progression of loss was noted for all tests as the degree of glaucoma increased. For subjects with mild glaucoma (MD -0.01 dB to -6.00 dB) significantly more data points fell outside the normal age-representative range for RG colour thresholds than for any other visual test, followed by motion thresholds. This was particularly the case for the parafoveal data compared with the foveal data. Thus, a multifaceted measure of binocular visual performance, incorporating RG colour and motion test at multiple locations, might provide a better index for comparison with quality of life measures in glaucoma.

Comparison of functional and morphological diagnostics in glaucoma patients and healthy subjects

PURPOSE

To evaluate the diagnostic value of microperimetry (MP), blue-on-yellow perimetry (B/YP), confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph, HRT, III) and optical coherence tomography (OCT) in discriminating eyes with early glaucoma from healthy subjects.

MATERIAL AND METHODS

Prospective examination of 22 eyes of subjects with early primary open-angle glaucoma and 24 eyes of healthy control subjects. After a complete ophthalmological examination, B/YP, MP, OCT and HRT III were determined. Morphological and functional parameters were analysed.

RESULTS

Mean sensitivity threshold values obtained with B/YP and MP did not show significant differences between glaucoma patients and the control group (p = 0.321 and p = 0.281). Retinal nerve fibre layer (RNFL) thickness was significantly decreased in patients with glaucoma with both HRT III and OCT (p = 0.018 and p < 0.001).

CONCLUSIONS

While B/YP and MP had no ability to discriminate between subjects with early glaucoma and healthy subjects, RNFL thickness measured with HRT III and OCT showed a significant difference. In early primary open-angle glaucoma, morphological changes like RNFL thickness seem to occur prior to functional defects in the visual field.

Measurement and correction of transverse chromatic offsets for multi-wavelength retinal microscopy in the living eye

A special challenge arises when pursuing multi-wavelength imaging of retinal tissue in vivo, because the eye's optics must be used as the main focusing elements, and they introduce significant chromatic dispersion. Here we present an image-based method to measure and correct for the eye's transverse chromatic aberrations rapidly, non-invasively, and with high precision. We validate the technique against hyperacute psychophysical performance and the standard chromatic human eye model. In vivo correction of chromatic dispersion will enable confocal multi-wavelength images of the living retina to be aligned, and allow targeted chromatic stimulation of the photoreceptor mosaic to be performed accurately with sub-cellular resolution.

Pattern ERG and RNFL thickness in hypertensive eyes with normal blue-yellow visual field

PURPOSE

To evaluate the transient pattern electroretinogram (t-PERG) and the retinal nerve fiber layer (RNFL) thickness in eyes with ocular hypertension (OH) and normal short-wavelength automated perimetry (SWAP).

METHODS

In 26 patients with bilateral OH with normal SWAP, and in 26 age and sex matched healthy controls, t-PERG recording and RNFL thickness measurement were performed. Mean deviation (MD) and pattern standard deviation (PSD) of a reliable full threshold 24-2 SWAP were considered. RNFL thickness was determined by OCT3. Monocular PERG were recorded by using a black and white checkerboard pattern (check size 0.9°, contrast 100 %, mean luminance 80 cd/m2) generated on a monitor and reversed in contrast (four reversals per second, 2 Hz) at a distance of 70 cm. Patients had optimal correction at viewing distance; no mydriatic or miotic eye drops were used. Silver/silver chloride skin electrodes were placed over the lower eyelids in the stimulated eye (active electrode) and in the patched eye (reference electrode); ground electrode was in the Fpz scalp. Peak-to peak amplitude of P50 (N35-P50) and N95 (P50-N95) waves, and implicit time of P50, were considered.

RESULTS

Compared to controls, in OH eyes, a reduction of N35-P50 amplitude (2.86 ± 1.49 vs. 3.77 ± 1.08 microvolts, -24.1 %, t-test p = 0.015), of average RNFL thickness (88 ± 11 vs. 96 ± 10 μm, -9.5 %, t-test p = 0.002), and of RNFL thickness in superior (p = 0.015) and inferior quadrant (p < 0.001), were found. Multivariate analysis showed that in OH eyes, N35-P50 amplitude was inversely related to intraocular pressure (IOP) (p = 0.001); no correlation was found between N35-P50 amplitude and MD, PSD, CCT or RNFL thickness.

CONCLUSIONS

In OH eyes, both PERG and RNFL thickness changes occur in hypertensive eyes with undamaged SWAP; the correlation of PERG amplitude with IOP, but not with RNFL thickness, suggests that such PERG changes are an effect of the IOP on retinal ganglion cells, rather than a sign of their loss.

Quantification of visual field loss in age-related macular degeneration

Background

An evaluation of standard automated perimetry (SAP) and short wavelength automated perimetry (SWAP) for the central 10–2 visual field test procedure in patients with age-related macular degeneration (AMD) is presented in order to determine methods of quantifying the central sensitivity loss in patients at various stages of AMD.

Methods

10–2 SAP and SWAP Humphrey visual fields and stereoscopic fundus photographs were collected in 27 eyes of 27 patients with AMD and 22 eyes of 22 normal subjects.

Results

Mean Deviation and Pattern Standard Deviation (PSD) varied significantly with stage of disease in SAP (both p<0.001) and SWAP (both p<0.001), but post hoc analysis revealed overlap of functional values among stages. In SWAP, indices of focal loss were more sensitive to detecting differences in AMD from normal. SWAP defects were greater in depth and area than those in SAP. Central sensitivity (within 1°) changed by −3.9 and −4.9 dB per stage in SAP and SWAP, respectively. Based on defect maps, an AMD Severity Index was derived.

Conclusions

Global indices of focal loss were more sensitive to detecting early stage AMD from normal. The SWAP sensitivity decline with advancing stage of AMD was greater than in SAP. A new AMD Severity Index quantifies visual field defects on a continuous scale. Although not all patients are suitable for SWAP examinations, it is of value as a tool in research studies of visual loss in AMD.