Performance of perimetric glaucoma staging systems and their preference patterns among the Indian eye care practitioners.

CONTEXT: Various systems are available to stage glaucomatous field defects into different severity grades. Still, the preference for such systems among Indian eye care practitioners (ECPs) and the consensus between them are not explored. PURPOSE: To compare the clinical performance of perimetric glaucoma staging systems and to assess their preference patterns among Indian ECPs. SETTING AND DESIGN: Retro-prospective cross-sectional study. METHODS: Three investigators stratified 400 perimetry reports using four systems: Hodapp Anderson Parrish (HAP), enhanced Glaucoma Severity Staging (eGSS), Advanced Glaucoma Intervention Study (AGIS), and Collaborative Initial Glaucoma Treatment Study (CIGTS). Their performance was compared in terms of agreement and association. Following this, 30 ECPs from across the country segregated a subset of reports (n = 20) into different stages based on their system of choice, and their preferences/perceptions about the available perimetry staging systems were enquired and documented. STATISTICAL ANALYSIS USED: Descriptive statistics, Kruskal-Wallis, Cohen's kappa, and Spearman's correlation. RESULTS: For the consolidated severity stages, substantial agreements (K ranging from 0.61 to 0.75) were found between all the systems, except for HAP-CIGTS (K = 0.58) and AGIS-CIGTS (K = 0.51). All ECPs were aware of perimetry staging systems, and a high preference was reported for HAP (97%) due to ease of implementation and interpretation. CONCLUSION: Among the four staging systems, the highest agreement was found between HAP and eGSS. A majority of ECPs proposed the need for a uniform classification system across the practices for clinical comparisons and patient education.

Effect of ethnic diversity on the saccadic reaction time among healthy Indian and Dutch adults.

Eye movement perimetry (EMP) expresses the decline in visual field (VF) responsiveness based on the deviation in saccadic reaction times (SRTs) from their expected age-similar responses (normative database). Since ethnic dissimilarities tend to affect saccade parameters, we evaluated the effect of such a factor on SRT and its interaction with age, stimulus eccentricity, and intensity. 149 healthy adults, spread into five age groups, drawn from Indian and Dutch ethnicities underwent a customized EMP protocol integrated with a saccade task from which the SRTs to 'seen' visual stimuli were computed. The EMP test had a total of 54 coordinates (five stimulus eccentricities) tested using Goldmann size III visual stimuli presented at four stimulus intensity (SI) levels against a constant background. Considering SRT as a dependent variable, a Generalized Linear Mixed Model analysis was conducted that revealed a statistically significant (p < 0.001) influence of ethnicity and interaction between the tested factors (ethnicity × age × stimulus eccentricity × intensity). However, during the post hoc analysis, out of the 100 possible pair-wise comparisons, only 6% (minor proportion) of the estimates showed statistical significance. Hence, the ethnic-specific differences need not be accounted for while implementing EMP in a diverse set of populations instead a collective database might serve the purpose.

Detection of visual field defects using Eye Movement Pediatric Perimetry in children with intracranial lesions: feasibility and applicability.

The study aimed at evaluating the feasibility of Eye Movement Pediatric Perimetry (EMPP) among children in detecting Visual Field Defects (VFDs) associated with Intracranial Lesions (IL). Healthy controls (n = 35) and patients diagnosed with IL (n = 19) underwent a comprehensive clinical evaluation followed by a Goldmann Visual Field (GVF) and a customised EMPP protocol. During EMPP, all the participants were encouraged to fixate on a central target and initiate Saccadic Eye Movement (SEM) responses towards randomly appearing peripheral stimuli. The SEM responses were recorded using an eye-tracking device and further inspected to calculate Performance Scores (PS), Saccadic Reaction Times (SRTs), and an EMPP Index (EMPI). The mean age (years) of the controls and cases were 7.3 (SD: 1.5) and 9.4 (SD: 2.4) respectively. Among the controls, the older children (≥7 years) showed statistically significantly faster SRTs (p = 0.008) compared to the younger group. The binocular EMPP measurements compared between the controls and the cases revealed no statistically significant differences in PS (p = 0.34) and SRT (p = 0.51). EMPP failed in 4 children because of data loss or unacceptably poor PS whereas GVF failed in 7 children due to unreliable subjective responses. Of the 16 reports, with regard to the central 30-degree VF, 63% of the outputs obtained from both methods were comparable. EMPP is a reliable method to estimate and characterise the central 30-degree VF in greater detail in children with IL. EMPP can supplement the conventional methods, especially in those children who fail to complete a long duration GVF test.

A haploscope based binocular pupillometer system to quantify the dynamics of direct and consensual Pupillary Light Reflex.

This study described the development of a haploscope-based pupillometer for the parametrization of the Pupillary Light Reflex (PLR), and its feasibility in a set of 30 healthy subjects (light or dark-colored irides) and five patients diagnosed with Relative Afferent Pupillary Defect (RAPD). Our supplementary aim focused on evaluating the influence of iris colour on the PLR to decide whether a difference in PLR parameters should be anticipated when this system is used across ethnicities. All the participants underwent a customized pupillometry protocol and the generated pupil traces, captured by an eye tracker, were analyzed using exponential fits to derive PLR parameters. A Pupil Response Symmetry (PRS) coefficient was calculated to predict the presence of RAPD. The mean (SD) Initial PD during dilation (3.2 (0.5) mm) and the minimum PD during constriction (2.9 (0.4) mm) in the light iris group had a statistically significant (p < 0.001) higher magnitude compared to the dark iris group. The normal limits of the PRS coefficient ranged from - 0.20 to + 1.07 and all RAPD patients were outside the calculated normal limits. This proposed system, analysis strategies, and the tested metrics showed good short-term repeatability and the potential in detecting pupil abnormalities in neuro-ophthalmic diseases.

Saccadic reaction time in mirror image sectors across horizontal meridian in eye movement perimetry.

In eye movement perimetry (EMP), the saccadic reaction time (SRT) to 'seen' visual stimuli are delayed in glaucoma. Evaluating SRT behaviour in hemi-field sectors could refine its clinical implication. The development phase included 60 controls retrospectively and for the test cohort in evaluation phase, another 30 healthy subjects and 30 glaucoma patients were recruited prospectively. The SRTs were used to calculate the normative limits within 5 predefined hemi-field sectors. Scores were assigned to probabilities for SRT at the level of 5%, 2.5% 1% and 0.5%. Per sector pair, a probability score limit (PSL) was calculated at each of the four levels and were compared with the scores obtained from the test cohort. The classification accuracy 'normal versus abnormal' was assessed for PSL in EMP and compared with glaucoma hemi-field test in standard automated perimetry. We found no statistically significant differences in SRTs between the mirror sectors in healthy subjects. The PSL at 2.5% had moderate classification accuracy with a specificity of 77% and sensitivity 70%. This could be suggestive of an SRT delay in the overall visual field in glaucoma.

Construction and Validation of LEA Hindi Chart: A Multicenter Study.

SIGNIFICANCE: This study explains the construction and validation of a chart in Hindi language, one of the commonly spoken languages in the world. The new visual acuity chart is called LEA Hindi chart. The calligraphy construction method described here can help develop other such acuity charts. PURPOSE: The purpose of this study was to construct and validate a new logMAR Hindi visual acuity chart (LEA Hindi chart) using principles similar to that of LEA symbols acuity chart. METHODS: A multicenter (three centers) study was conducted in two phases. The first phase consisted of identifying and constructing the Hindi optotypes using calligraphy techniques. The Hindi optotypes were calibrated against the Landolt C optotypes by measuring the threshold distance for visual acuity. In the second phase, the newly constructed LEA Hindi chart was validated against the Early Treatment Diabetic Retinopathy Study (ETDRS) and Landolt C visual acuity charts. Sixty participants were enrolled for the first phase (centers 1 and 2) and for the second phase of the study (centers 1 and 3). Additional 15 participants were enrolled (center 1) for testing repeatability. RESULTS: Four Hindi optotypes were identified and used for the construction of the chart (first phase). In the second phase, the LEA Hindi chart was found to be comparable with both the Landolt C, (logMAR acuity difference, 0.03 ± 0.13; P > .18) and ETDRS (logMAR acuity difference, -0.02 ± 0.09; P > .25) charts. All the three charts were also found to be repeatable (95% limits of agreement within 0.24 logMAR). CONCLUSIONS: The newly constructed LEA Hindi visual acuity chart gave comparable levels of visual acuity as that measured in an ETDRS or Landolt C charts. The repeatability was also similar to the standard charts. The LEA Hindi visual acuity chart can be used for patients comfortable with Hindi language and also in studies requiring multiple measurements of visual acuity, to avoid familiarity to a given chart.

Visual Field Plots: A Comparison Study Between Standard Automated Perimetry and Eye Movement Perimetry.

PRéCIS:: This eye movement perimetry (EMP) study describes the development of saccadic reaction time (SRT)-based visual field plots, which could effectively display the presence, location, and extent of glaucomatous defects and support clinical decision-making. PURPOSE: EMP is capable of discriminating normal from glaucomatous visual field defects on the basis of average delays in SRTs. To classify the presence and extent of age-corrected visual field defects, it is required to create SRT-based probability maps. AIM: The aim of this study was to create visual field probability plots based on SRTs and to evaluate their clinical applicability by 2 glaucoma specialists. MATERIALS AND METHODS: The development phase included 95 controls segregated into 5 age-bins to estimate normative limits of SRT. Next, for the testing phase, a set of 28 healthy subjects and 24 glaucoma patients were recruited who underwent standard automated perimetry (SAP) and EMP visual field testing. Fifty-two SAP and EMP plots were presented to 2 glaucoma specialists to classify them as normal or abnormal and to identify the defect location and pattern as 1 or more of 7 predefined categories. RESULTS: The glaucoma specialists showed a sensitivity of 100% and a specificity of 93% and 96% for identifying normal versus abnormal visual field. For specialists 1 and 2, 85% and 92%, respectively, of EMP reports were assigned to the same category as SAP. The reports that did not agree with SAP were graded to a higher defect pattern. The intermethod agreement for specialists 1 and 2 was κ 0.92 and 0.96, respectively. CONCLUSION: SRT-based visual field probability plots provided a comprehensive summary of an individual's visual field status and showed comparable clinical applicability to that of SAP plots.

Effect of Age, Sex, Stimulus Intensity, and Eccentricity on Saccadic Reaction Time in Eye Movement Perimetry.

PURPOSE: In eye movement perimetry (EMP), the extent of the visual field is tested by assessing the saccades using an eye tracker. The aim of the present study was to determine the effects of age and sex of the subjects, the eccentricity and intensity of the peripheral stimuli on saccadic reaction time (SRT), and the interaction between these parameters in healthy participants. METHODS: Healthy participants aged between 20 to 70 years underwent a complete ophthalmic examination and an EMP test. SRT was determined from detected peripheral stimuli of four intensity levels. A multilevel mixed-model analysis was used to verify the influence of subject and stimulus characteristics on SRT within the tested visual field. RESULTS: Ninety-five subjects (mean age 43.0 [15.0] years) were included. Age, stimulus intensity, and eccentricity had a statistically significant effect on SRT, not sex. SRTs were significantly faster with increasing stimulus intensity and decreasing eccentricity (P < 0.001). At the lowest stimulus intensity of 192 cd/m2, a significant interaction was found between age and eccentricity. CONCLUSIONS: The current study demonstrated significant SRT dependence across the visual field measured up to 27°, irrespective of sex. The presented SRT values may serve as a first normative guide for EMP. TRANSLATIONAL RELEVANCE: This report of SRT interaction can aid in refining its use as a measure of visual field responsiveness.

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.

Construction and validation of logMAR visual acuity charts in seven Indian languages.

Purpose: The evaluation of visual impairment requires the measurement of visual acuity with a validated and standard logMAR visual acuity chart. We aimed to construct and validate new logMAR visual acuity chart in Indian languages (Hindi, Bengali, Telugu, Urdu, Kannada, Malayalam, and Assamese). Methods: The commonly used font in each language was chosen as the reference and designed to fit the 5 × 5 grid (Adobe Photoshop). Ten letters (easiest to difficult) around median legibility score calculated for each language based on the results of legibility experiment and differing by 10% were selected. The chart was constructed based on the standard recommendations. The repeatability of charts was tested and also compared with a standard English Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart for validation. Results: A total of 14 rows (1.0 to -0.3 logMAR) with five letters in each line were designed with the range of row legibility between 4.7 and 5.3 for all the language charts. Each chart showed good repeatability, and a maximum difference of four letters was noted. The median difference in visual acuity was 0.16 logMAR for Urdu and Assamese chart compared to ETDRS English chart. Hindi and Malayalam chart had a median difference of 0.12 logMAR. When compared to the English chart a median difference of 0.14 logMAR was noted in Telugu, Kannada, and Bengali chart. Conclusion: The newly developed Indian language visual acuity charts are designed based on the standard recommendations and will help to assess visual impairment in people of these languages across the country.

Comparison of saccadic reaction time between normal and glaucoma using an eye movement perimeter.

AIM: To compare the saccadic reaction time (SRT) in both the central and peripheral visual field in normal and glaucomatous eyes using eye movement perimetery (EMP). MATERIALS AND METHODS: Fifty-four normal and 25 glaucoma subjects underwent EMP and visual field testing on the Humphrey Field Analyser (HFA) 24-2 program. The EMP is based on infrared tracking of the corneal reflex. Fifty-four test locations corresponding to the locations on the 24-2 HFA program were tested. SRTs at different eccentricities and for different severities of glaucoma were compared between normal and glaucoma subjects. RESULTS: Mean SRT was calculated for both normal and glaucoma subjects. Mann-Whitney U test showed statistically significant (P < 0.001) differences in SRT's between normal and glaucoma subjects in all zones. CONCLUSION: SRT was prolonged in eyes with glaucoma across different eccentricities.