Multiple Sclerosis: What Methods are Available for the Assessment of Subclinical Visual System Damage?

We aimed to assess the visual fields and optical coherence tomography (OCT) measurements in patients with multiple sclerosis (MS) to detect subclinical visual system disease. The study included 15 MS patients with previous optic neuritis (Group I), 17 MS patients without previous optic neuritis (Group II), and 14 healthy controls (Group III). Each subject underwent standard automated perimetry (SAP), frequency doubling technology perimetry (FDTP), and OCT. The mean deviation of SAP in Group I was lower than those in Groups II (p = .018) and III (p = .001). The pattern standard deviation of SAP in Group I was higher than those in Group III (p < .0001). The mean deviation of FDTP in Groups I and II was lower than those in Group III (p = .0001 and p = .016, respectively). The temporal quadrant of the retinal nerve fibre layer in Group I was thinner than those in Groups II and III (p = .005 and p = .003, respectively). The mean macular volume in Group I was thinner than those in Groups II and III (p = .004 and p = .002, respectively). A single method is inadequate for establishing early and/or mild visual impairment in MS. All conventional and non-conventional techniques are complementary in demonstrating subclinical visual damage in MS.

Eye Movement Perimetry and Frequency Doubling Perimetry: clinical performance and patient preference during glaucoma screening.

PURPOSE: To evaluate the screening accuracy of an Eye Movement Perimetry (EMP) in comparison with Frequency Doubling Perimetry (FDP) and to investigate the patient preference and perception towards these visual field screening methods. METHODS: A total of 104 healthy subjects (mean age (SD) of 48 (14) years) and 73 glaucoma patients (mean age (SD) of 52 (13) years) were recruited. All the participants underwent a comprehensive ophthalmic evaluation including the 24-2 SITA standard protocol on the Humphrey Field Analyzer (HFA). This was followed by the 26-point protocol in EMP and the C-20-1 protocol in FDP. During EMP, all subjects were instructed to fixate a central target and to look at the detected peripheral target, followed by refixation of the central target and Saccadic Reaction Time (SRT) towards each of the "seen" stimuli was calculated. Next, a questionnaire was administered to evaluate the patient preference and perception towards the perimetry techniques. Mean SRTs and Robin scores were used to plot Receiver Operating Characteristics (ROC) curves to determine the screening accuracies. From the questionnaire survey, the frequency distributions of the responses were calculated. RESULTS: Robin score and SRT were significantly increased in glaucoma patients in comparison with the age-matched healthy subjects (p < 0.001). The ROC analysis revealed comparable Area Under the Curve (AUC) values (0.95, p = 0.81) with a specificity of 95.2% for FDP and 96.2% for EMP with a sensitivity of 87.7%. Thirty-seven percent of the older age group (≥ 40 years) and 65% of severe glaucoma patients showed preference for EMP over FDP. CONCLUSIONS: This study results indicate that the customized protocol in EMP provides efficient and rapid means of screening visual field defects in glaucoma, which compared well with FDP. Elderly healthy participants and patients with moderate and severe glaucomatous defects preferred EMP as it permitted natural reflexive eye movements thereby resembling a real-life test setting.

Angle closure glaucoma in rural and urban populations in eastern India-The Hooghly River Glaucoma Study.

Purpose: To estimate the prevalence, features, and associations of primary angle closure disease (PACD) in rural and urban populations from West Bengal in eastern India. Methods: This was a population-based cross-sectional study with two arms, rural and urban. The rural study area consisted of 28 contiguous villages from 13 gram panchayats in Balagarh Police Station, with rural base hospital at Dhobapara, Balagarh Police Station, in the village Kuliapara of Hooghly district. A tertiary eye hospital in central Kolkata was the urban study center. Individuals residing in the study area aged 40 years and above were included in this study using multistage random cluster sampling. All subjects underwent a detailed ophthalmic examination at our base hospitals including applanation tonometry, ultrasound pachymetry, gonioscopy, and frequency doubling technology perimetry. Data collected were analyzed using SPSS 13. Multiple logistic regressions were used to analyze risk factors for PACD. Results: A total of 7,408 and 7,248 subjects aged 40 years or older were enumerated from Hooghly district and Kolkata city, respectively. PACD was detected in 1.9% subjects in rural arm and 1.54% subjects in the urban arm (P < 0.001). In rural arm, 0.3% had PACS, 0.56% had PAC, and 1.03% had PACG. In urban arm, 0.22% had PACS, 0.35% had PAC, and 0.97% had PACG. Conclusion: The study concludes that higher age, higher CCT, and shorter axial length/presence of hyperopia are important independent predictors of ACD. ACD is more common in eastern India than previous estimates.

The neurovascular unit and the pathophysiologic basis of diabetic retinopathy.

PURPOSE: To relate the concept of the retinal neurovascular unit and its alterations in diabetes to the pathophysiology of diabetic retinopathy. METHODS: Case illustrations and conceptual frameworks are presented that illustrate adaptive and maladaptive "dis-integration" of the retinal neurovascular unit with the progression of diabetes. RESULTS: Retinopathy treatment should address pathophysiologic processes rather than pathologic lesions as is current practice. CONCLUSIONS: Future improvements in the treatment of diabetic retinopathy requires deeper understanding of the cellular and molecular changes induced by diabetes, coupled with the use of quantitative phenotyping methods that assess the pathophysiologic processes.

Structural and Functional Evaluations for the Early Detection of Glaucoma.

The early detection of glaucoma is imperative in order to preserve functional vision. Structural and functional methods are utilized to detect and monitor glaucomatous damage and the vision loss it causes. The relationship between these detection measures is complex and differs between individuals, especially in early glaucoma. Using both measures together is advised in order to ensure the highest probability of glaucoma detection, and new testing methods are continuously developed with the goals of earlier disease detection and improvement of disease monitoring. The purpose of this review is to explore the relationship between structural and functional glaucoma detection and discuss important technological advances for early glaucoma detection.

Frequency doubling technology and standard automated perimetry in detection of glaucoma among glaucoma suspects.

BACKGROUND: Frequency Doubling perimetry (FDT) has been found to precede visual loss detected by standard automated perimetry (SAP) by as much as four years and the initial development of glaucomatous visual field loss as measured by SAP was found to occur in regions that had previously demonstrated abnormalities on FDT testing. METHODS: A study on 55 glaucoma suspects (determined as per American Academy Guidelines, Preferred Practice Pattern, Oct 2010), was compared to 50 healthy participants (HP). Both glaucoma suspects and HP underwent SAP and FDT in random order. Only reliable fields were compared. RESULTS: Mean deviation of FDT Matrix was significantly lower than SAP SITA in suspect and healthy group ; two devices showed significant correlation amongst both groups (suspects p = 0.002, healthy p = 0.011). Significant difference was found in PSD of SAP SITA and FDT Matrix (p = 0.001) in the glaucoma suspect group, PSD of FDT Matrix was significantly higher than PSD of SAP SITA in the healthy group (p < 0.001). PSD of SAP SITA significantly correlated with FDT Matrix PSD in glaucoma group (r = 0.579; p = 0.001) but no significant correlation found in healthy group (r = 0.153; p = 0.290). Percentages of normal test locations significantly higher in FDT Matrix compared to SAP SITA in glaucoma suspects and healthy participants. CONCLUSION: FDT correlates well with SAP and may be used for patients who are unable to perform well and reliably with SAP but does not show any features of earlier glaucoma changes in this study.

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.

Comparison of Humphrey Matrix frequency doubling technology to standard automated perimetry in neuro-ophthalmic disease.

PURPOSE: We compared Humphrey Matrix FDT 30-2 (FDT) and Humphrey Visual Field Analyzer 30-2 SITA standard (SAP) in the assessment of anterior (optic nerve or chiasm) and posterior (retro-chiasmal) afferent visual pathway defects. MATERIALS AND METHODS: In this retrospective comparative study, the charts of 37 patients (16 males, range 13-84 years, mean 72.1), with neuro-ophthalmic visual field defects who were tested with both FDT and SAP, were reviewed. Two masked graders assessed the concordance and extent of field defects between the perimeters. The mean concordance between anterior and posterior disease was compared using the Wilcoxon rank sum test. The mean deviation (MD) and pattern standard deviation (PSD) of each perimeter were correlated with the Spearman coefficient. RESULTS: Twenty-eight patients had anterior and nine had posterior disease. Most had a fair or good concordance (89.3% anterior, 88.9% posterior). When comparing anterior to posterior disease, the mean concordance of the defects of the two parameters was not statistically different (P = 0.94 and P = 0.61 for total deviation and pattern deviation, respectively). The MD and PSD between perimeters had a significant correlation. CONCLUSIONS: Our series, using 30-2 field analysis, demonstrates fair to good correlation between FDT and SAP in the majority of patients. In roughly 10% findings between FDT and SAP were discordant. This difference was similar for anterior and posterior disease.

The effect of yellow tinted intraocular lenses on the result of frequency doubling perimetry after cataract surgery.

PURPOSE: To investigate the effect of yellow tinted intraocular lenses (IOLs), implanted in the bag after phacoemulsification, on the result of frequency doubling technique (FDT) perimetry. METHODS: For 68 eyes of 52 patients, an IOL was implanted in the bag after phacoemulsification. The patients were categorized into three groups according to the type of implanted IOLs used. IOLs were selected randomly among two types of yellow IOLs (Acrysof SN60WF IOL, Hoya YA60BBR IOL) and a clear IOL was used as a control. A FDT Humphrey matrix was performed 2 months after the surgery. The mean deviation (MD) and pattern standard deviation (PSD) among these three groups was analyzed using Mann-Whitney U-test. RESULTS: TWO MONTHS AFTER THE PROCEDURE, THERE WAS NO SIGNIFICANT DIFFERENCE BETWEEN EACH OF THE THREE GROUPS: the clear IOL and Hoya YA60BBR IOL (MD, p = 0.21; PSD, p = 0.27), the clear IOL and Alcon SN60WF IOL (MD, p = 0.11; PSD, p = 0.22), and the Hoya YA60BBR IOL and Alcon SN60WF IOL (MD, p = 0.33; PSD, p = 0.56). CONCLUSIONS: When interpreting the result of the FDT after cataract surgery, the color and type of IOLs used should not be considered.