Remi-fent 1-A pragmatic randomised controlled study to evaluate the feasibility of using remifentanil or fentanyl as sedation adjuncts in mechanically ventilated patients.

Objective: To evaluate the feasibility of conducting a prospective randomised controlled trial (pRCT) comparing remifentanil and fentanyl as adjuncts to sedate mechanically ventilated patients. Design: Single-center, open-labelled, pRCT with blinded analysis. Setting: Australian tertiary intensive care unit (ICU). Participants: Consecutive adults between June 2020 and August 2021 expected to receive invasive ventilation beyond the next day and requiring opioid infusion were included. Exclusion criteria were pregnant/lactating women, intubation >12 h, or study-drug hypersensitivity. Interventions: Open-label fentanyl and remifentanil infusions per existing ICU protocols. Outcomes: Primary outcomes were feasibility of recruiting ≥1 patient/week and >90 % compliance, namely no other opioid infusion used during the study period. Secondary outcomes included complications, ICU-, ventilator- and hospital-free days, and mortality (ICU, hospital). Blinded intention-to-treat analysis was performed concealing the allocation group. Results: 208 patients were enrolled (mean 3.7 patients/week). Compliance was 80.6 %. More patients developed complications with fentanyl than remifentanil: bradycardia (n = 44 versus n = 21; p < 0.001); hypotension (n = 78 versus n = 53; p < 0.01); delirium (n = 28 versus n = 15; p = 0.001). No differences were seen in ICU (24.3 % versus 27.6 %,p = 0.60) and hospital mortalities (26.2 % versus 30.5 %; p = 0.50). Ventilator-free days were higher with remifentanil (p = 0.01). Conclusions: We demonstrated the feasibility of enrolling patients for a pRCT comparing remifentanil and fentanyl as sedation adjuncts in mechanically ventilated patients. We failed to attain the study-opioid compliance target, likely because of patients with complex sedative/analgesic requirements. Secondary outcomes suggest that remifentanil may reduce mechanical ventilation duration and decrease the incidence of complications. An adequately powered multicentric phase 2 study is required to evaluate these results.

A Survey of Clinicians Regarding Goals of Care for Patients with Severe Comorbid Illnesses Hospitalized for an Acute Deterioration.

Background: Patients with terminal illnesses hospitalized with acute deteriorations often suffer from unnecessary/inappropriate therapies at the end of their lives. Appropriate advance care planning (ACP) practices aligned to patients' goals of care may mitigate this. Materials and methods: To explore the rationale for clinical decision-making in hospitalized patients with terminal illnesses and formulate a practice pathway to streamline care. Between May and December 2018, a questionnaire survey with three case vignettes derived from intensive care unit (ICU) patients was emailed to ICU, respiratory and renal doctors, and nurses in two Sydney hospitals. Respondents chose various management options ranging from all active therapies to palliation. The primary outcome was the proportion of responses for each management option. With these and a thematic analysis of responses to identify barriers to ACP practice, a practice pathway was formulated. Results: Of the 310 invited clinicians, 178 responded (57.4%). About 89.2% of respondents reported caring for dying patients frequently. Sixty percent saw patients suffering from prolonged therapies. Most respondents deemed patients in the case vignettes to be terminally ill, warranting ACP discussions. However, many still wanted to treat the acute deterioration with active ICU-level interventions. Most respondents reported being comfortable in having ACP discussions. Conclusion: The survey showed discordance between the stated opinions and the choice of management options for terminally ill patients with acute deteriorations; possibly due to the lack of a considered approach in choosing management options that align with medical consensus and the patient's/family's wishes, a practice pathway is suggested to improve management. How to cite this article: Sarangi RK, Rajamani A, Lakshmanan R, Srinivasan S, Arvind H. A Survey of Clinicians Regarding Goals of Care for Patients with Severe Comorbid Illnesses Hospitalized for an Acute Deterioration. Indian J Crit Care Med 2022;26(4):457-463.

Criteria, Processes, and Determination of Competence in Basic Critical Care Echocardiography Training: A Delphi Process Consensus Statement by the Learning Ultrasound in Critical Care (LUCC) Initiative.

BACKGROUND: With the paucity of high-quality studies on longitudinal basic critical care echocardiography (BCCE) training, expert opinion guidelines have guided BCCE competence educational standards and processes. However, existing guidelines lack precise detail due to methodological flaws during guideline development. RESEARCH QUESTIONS: To formulate methodologically robust guidelines on BCCE training using evidence and expert opinion, detailing specific criteria for every step, we conducted a modified Delphi process using the principles of the validated AGREE-II tool. Based on systematic reviews, the following domains were chosen: components of a longitudinal BCCE curriculum; pass-grade criteria for image-acquisition and image-interpretation; and formative/summative assessment and final competence processes. STUDY DESIGN AND METHODS: Between April 2020 and May 2021, a total of 21 BCCE experts participated in four rounds. Rounds 1 and 2 used five web-based questionnaires, including branching-logic software for directed questions to individual panelists. In round 3 (videoconference), the panel finalized the recommendations by vote. During the journal peer-review process, Round 4 was conducted as Web-based questionnaires. Following each round, the agreement threshold for each item was determined as ≥ 80% for item inclusion and ≤ 30% for item exclusion. RESULTS: Following rounds 1 and 2, agreement was reached on 62 of 114 items. To the 49 unresolved items, 12 additional items were added in round 3, with 56 reaching agreement and five items remaining unresolved. There was agreement that longitudinal BCCE training must include introductory training, mentored formative training, summative assessment for competence, and final cognitive assessment. Items requiring multiple rounds included two-dimensional views, Doppler, cardiac output, M-mode measurement, minimum scan numbers, and pass-grade criteria. Regarding objective criteria for image-acquisition and image-interpretation quality, the panel agreed on maintaining the same criteria for formative and summative assessment, to categorize BCCE findings as major vs minor and a standardized approach to errors, criteria for readiness for summative assessment, and supervisory options. INTERPRETATION: In conclusion, this expert consensus statement presents comprehensive evidence-based recommendations on longitudinal BCCE training. However, these recommendations require prospective validation.

Methodologic Quality of Guidelines for Training or Competence Processes for Basic Point-of-Care Echocardiography in Critical Care: A Systematic Review of the Literature.

BACKGROUND: The formulation of expert opinion guidelines has several sources of bias that may adversely affect their quality. To minimize bias, guideline creators must use rigorous methodology. There has been no appraisal of the methodologic quality of basic critical care echocardiography (BCCE) training/education guidelines. RESEARCH QUESTION: What is the methodologic quality of expert guidelines/recommendations on BCCE training? STUDY DESIGN AND METHODS: The review was performed by a multidisciplinary team including intensive care specialists, a hospital scientist, a trainee, a nurse sonographer, and a public health expert. Four databases (PubMed, OVID-Embase, Clarivate Analytics Web of Science, and Google Scholar) were searched on July 31, 2020, to identify guidelines on BCCE training/education. Every guideline was assessed subjectively for the degree of detail of the recommendations and assessed objectively by using the AGREE-II critical appraisal tool for clinical practice guidelines to generate a scaled domain score. A score ≥ 75% in every domain was the cut off for guidelines to be used without modifications. RESULTS: From 4,288 abstracts screened, 24 guidelines met the inclusion criteria. Very few guidelines made clear recommendations regarding introductory courses: physics (n = 6 [25%]), instrumentation (n = 5 [20.8%]), image acquisition theory (n = 6 [25%]), course curriculum (n = 5 [[20.8%]), pre-course/post-course tests (n = 1 [4.2%]), minimum course duration (n = 6 [25%]), or trainer qualifications (n = 5 [20.8%]). Very few provided clear recommendations for longitudinal competence programs: clinically indicated scans (n = 8 [33.3%]), logbook (n = 14 [58.3%]), image storage (n = 9 [37.5%]), formative assessment (n = 6 [25%]), minimum scan numbers (n = 14 [58.3%]), image acquisition competence (n = 3 [12.5%]), image interpretation competence (n = 2 [8.3%]), and credentialing/certification (n = 3 [12.5%]). Five guidelines (20.8%) attained a scaled overall AGREE-II score ≥ 75%. One guideline (4.2%) attained scores ≥ 75% in every domain. INTERPRETATION: The methodologic appraisal of BCCE-training guidelines showed widespread deficiencies in guideline formulation processes. The impact of these deficiencies on the validity of the recommendations requires further evaluation in longitudinal studies.

A Deep Learning-Based Algorithm Identifies Glaucomatous Discs Using Monoscopic Fundus Photographs.

PURPOSE: To develop and test the performance of a deep learning-based algorithm for glaucomatous disc identification using monoscopic fundus photographs. DESIGN: Fundus photograph database study. PARTICIPANTS: Four thousand three hundred ninety-four fundus photographs, including 3768 images from previous Sydney-based clinical studies and 626 images from publicly available online RIM-ONE and High-Resolution Fundus (HRF) databases with definitive diagnoses. METHODS: We merged all databases except the HRF database, and then partitioned the dataset into a training set (80% of all cases) and a testing set (20% of all cases). We used the HRF images as an additional testing set. We compared the performance of the artificial intelligence (AI) system against a panel of practicing ophthalmologists including glaucoma subspecialists from Australia, New Zealand, Canada, and the United Kingdom. MAIN OUTCOME MEASURES: The sensitivity and specificity of the AI system in detecting glaucomatous optic discs. RESULTS: By using monoscopic fundus photographs, the AI system demonstrated a high accuracy rate in glaucomatous disc identification (92.7%; 95% confidence interval [CI], 91.2%-94.2%), achieving 89.3% sensitivity (95% CI, 86.8%-91.7%) and 97.1% specificity (95% CI, 96.1%-98.1%), with an area under the receiver operating characteristic curve of 0.97 (95% CI, 0.96-0.98). Using the independent online HRF database (30 images), the AI system again accomplished high accuracy, with 86.7% in both sensitivity and specificity (for ophthalmologists, 75.6% sensitivity and 77.8% specificity) and an area under the receiver operating characteristic curve of 0.89 (95% CI, 0.76-1.00). CONCLUSIONS: This study demonstrated that a deep learning-based algorithm can identify glaucomatous discs at high accuracy level using monoscopic fundus images. Given that it is far easier to obtain monoscopic disc images than high-quality stereoscopic images, this study highlights the algorithm's potential application in large population-based disease screening or telemedicine programs.

Outcomes: Trabeculectomy Bleb Needle Revision With 5-Fluorouracil.

PURPOSE: To evaluate outcomes of trabeculectomy bleb needle revision with 5-fluorouracil augmentation performed in the operating theater. METHODS: Retrospective study of all patients undergoing trabeculectomy bleb needle revisions in the operating theater performed by a single surgeon in a metropolitan hospital in Australia. A total of 51 needle revisions were performed on 33 eyes over a mean follow-up time of 1.81±1.56 years. RESULTS: A total of 29% achieved intraocular pressure (IOP) ≤20 mm Hg off all glaucoma medications, and an additional 39% achieved qualified success with the addition of glaucoma medications, giving overall success of 68%. Analyzing success rate for target IOP≤16 mm Hg, 24% achieved target off all glaucoma medications, 35% achieved qualified success with the addition of glaucoma medications, giving an overall success rate of 59%. There was a statistically significant improvement in IOP, as compared with preoperative levels, at all timepoints postoperatively (P<0.05). However, number of glaucoma medications remained unchanged (P>0.05) contributing to the high percentage of qualified successes. Visual acuity remained unchanged and there were no major postoperative complications. The Kaplan-Meier survival shows a survival rate of 60% with IOP≤20 mm Hg and 40% for IOP≤16 mm Hg at 5 years. CONCLUSIONS: Trabeculectomy needle revision is a useful option for the management of elevated IOP in the presence of a failed or failing trabeculectomy bleb. However, as with trabeculectomy, there tends to be a failure rate over time. This often leads to reinstitution of glaucoma medications and/or further needle revisions to maintain IOPs at target level. The procedure itself is minimally invasive with an acceptable safety profile.

Optimizing the Detection of Preperimetric Glaucoma by Combining Structural and Functional Tests.

PURPOSE: We evaluated the performance of low contrast achromatic (LLA) multifocal visual evoked potentials (mfVEP) in preperimetric glaucoma and compared its diagnostic performance to other early diagnostic tests. We identified the clinically most useful tests and combinations in preperimetric glaucoma. METHODS: We studied 59 patients with at least one glaucomatous disc, with normal, reliable visual fields in that eye, and 17 normal controls. All participants underwent complete ophthalmic examination including Humphrey visual fields (HVF), short wavelength automated perimetry (SWAP), frequency doubling perimetry (FDT Matrix), Spectralis optical coherence tomography (OCT), Heidelberg retinal tomography (HRT 3), and color stereoscopic optic disc photographs. We recorded mfVEPs using LLA stimulation. RESULTS: We studied 85 eyes of 59 patients (64.89 ± 8.15 years) and 34 eyes of 17 controls (64.28 ± 13.06 years; P = 0.64). Heidelberg retinal tomography and LLA mfVEP demonstrated the best sensitivities (50.6% and 51.8%, respectively) in identifying preperimetric glaucoma, and were not significantly different from each other. Both tests had significantly better sensitivity than all other tests (P < 0.0001). Of the eyes, 76.5% were identified by the combination of (any one of) LLA mfVEP and HRT. Sensitivity of the combination was significantly better than any of the individual tests (P < 0.05 for all pairs), or any other combinations of tests, with better negative than positive predictive value. CONCLUSIONS: The LLA mfVEP test identified approximately 50.6% eyes with preperimetric glaucoma, which was significantly higher than other perimetric methods, and similar to HRT. The combination of LLA mfVEP and HRT had exceptionally high sensitivity of 76.5% for preperimetric glaucoma.

Relationship between optical coherence tomography and electrophysiology of the visual pathway in non-optic neuritis eyes of multiple sclerosis patients.

PURPOSE: Loss of retinal ganglion cells in in non-optic neuritis eyes of Multiple Sclerosis patients (MS-NON) has recently been demonstrated. However, the pathological basis of this loss at present is not clear. Therefore, the aim of the current study was to investigate associations of clinical (high and low contrast visual acuity) and electrophysiological (electroretinogram and multifocal Visual Evoked Potentials) measures of the visual pathway with neuronal and axonal loss of RGC in order to better understand the nature of this loss. METHODS: Sixty-two patients with relapsing remitting multiple sclerosis with no previous history of optic neuritis in at least one eye were enrolled. All patients underwent a detailed ophthalmological examination in addition to low contrast visual acuity, Optical Coherence Tomography, full field electroretinogram (ERG) and multifocal visual evoked potentials (mfVEP). RESULTS: There was significant reduction of ganglion cell layer thickness, and total and temporal retinal nerve fibre layer (RNFL) thickness (p<0.0001, 0.002 and 0.0002 respectively). Multifocal VEP also demonstrated significant amplitude reduction and latency delay (p<0.0001 for both). Ganglion cell layer thickness, total and temporal RNFL thickness inversely correlated with mfVEP latency (r = -0.48, p<0.0001 respectively; r = -0.53, p<0.0001 and r = -0.59, p<0.0001 respectively). Ganglion cell layer thickness, total and temporal RNFL thickness also inversely correlated with the photopic b-wave latency (r = -0.35, p = 0.01; r = -0.33, p = 0.025; r = -0.36, p = 0.008 respectively). Multivariate linear regression model demonstrated that while both factors were significantly associated with RGC axonal and neuronal loss, the estimated predictive power of the posterior visual pathway damage was considerably larger compare to retinal dysfunction. CONCLUSION: The results of our study demonstrated significant association of RGC axonal and neuronal loss in NON-eyes of MS patients with both retinal dysfunction and post-chiasmal damage of the visual pathway.

Axonal loss in non-optic neuritis eyes of patients with multiple sclerosis linked to delayed visual evoked potential.

OBJECTIVE: Recent studies demonstrate significant thinning of the retinal nerve fiber layer (RNFL) in multiple sclerosis (MS) non-optic neuritis (MS-NON) eyes. However, the pathologic basis of this reduction is not clear. The aim of the current study was to investigate the relationship of the RNFL thickness in MS-NON eyes with latency delay of the multifocal visual evoked potential (mfVEP), a surrogate marker of the visual pathway demyelination. METHODS: Total and temporal RNFL thickness and latency of the mfVEP in 45 MS-NON eyes of 45 patients with relapsing-remitting MS and 25 eyes of age- and gender-matched controls were measured and analyzed. RESULTS: There was significant reduction of total and temporal RNFL thickness (p = 0.015 and p = 0.006, respectively) and significant latency delay (p < 0.0001) in MS-NON eyes. Both total and temporal RNFL thickness were associated with latency of the mfVEP (r2 = 0.43, p < 0.0001 and r2 = 0.36, p = 0.001, respectively). MS-NON eyes with normal latency (n = 26) showed no significant reduction of RNFL thickness compared with controls (p = 0.44 and p = 0.1 for total and temporal RNFL, respectively), whereas eyes with delayed latency (n = 19) demonstrated significantly thinner RNFL (p = 0.001 and p = 0.0005). MS-NON eyes with delayed latency also had significantly thinner RNFL compared with those with normal latencies (p = 0.013 and p = 0.02). In patients with no previous optic neuritis in either eye, delayed latency and reduced RNFL were bilateral whenever present. CONCLUSIONS: The study demonstrated significant association between RNFL loss and a latency delay of the mfVEP in MS-NON eyes.

Reproducibility of multifocal VEP latency using different stimulus presentations.

The aims of the article were to study the reproducibility of latency of multifocal visual evoked potential (mfVEP) recorded using different stimulus presentations and to identify the peak with least variability. Ten normal subjects, aged between 22 and 52 years (mean age 32 ± 8.37 years), participated in the study. All subjects underwent mfVEP testing with pattern reversal and pattern pulse stimulus presentations. The stimulus subtends 26° from fixation and includes 24 segments. Only the vertical channel was recorded on all subjects. Testing was repeated after 1-2 weeks. Only the right eye of all subjects was analysed. Segments with low signal-to-noise ratios (SNR < 1.5) were excluded from analysis. The latencies were analysed to confirm values from the same peak for the two tests. The latency values were then analysed for the start of the response, the first peak and the second peak. The waveforms were reproducible throughout the field. Reproducibility of latency at the "start of the response" was significantly lesser than the first and the second peaks studied, while the reproducibility of latency at the first peak was not statistically different from the second peak for either pattern reversal or pattern pulse stimulation. The latency values were not different between the first and the second sessions for either pattern reversal or pattern pulse stimulation for any of the peaks. The pattern reversal stimulus presentation produced less variability in latency. The first peak is the most reproducible among the three measures in both the stimulus presentation.

Optic disc dimensions and cup-disc ratios among healthy South Indians: The Chennai Glaucoma Study.

PURPOSE: To present optic disc and cup dimensions, cup-disc ratios (CDRs) and asymmetry among healthy South Indians, and their associations with ocular and systemic variables. METHODS: A total of 623 healthy phakic participants of the Chennai Glaucoma Study underwent complete eye examinations including optic disc stereo-photography. Planimetry was performed under stereo-viewing conditions. The morphological type of cupping (no cups, steep cups, partly sloping and fully sloping cups) was identified based on a modification of the classification by Jonas et al.( 11 ) The associations of planimetric measures (optic disc area, cup area and vertical cup-disc ratio [VCDR]) with age, gender, height, intraocular pressure, refraction, astigmatism, axial length and corneal thickness as explanatory variables were examined. The associations of asymmetries in the above planimetric measures with age, gender and asymmetries of the above explanatory variables were examined. RESULTS: Mean optic disc and cup areas were 2.82 ± 0.52 mm(2) and 0.53 ± 0.39 mm(2). Mean CDR was 0.36 ± 0.18. Men had larger discs (P = 0.03). Cup area and VCDR revealed significant associations with disc area (P <0.0001) and type of cupping (P < 0.0001). Mean disc and cup area asymmetries were 0.19 ± 0.16 mm(2) and 0.15 ± 0.15 mm(2). Mean VCDR asymmetry was 0.07 ± 0.08 mm(2). Cup area and VCDR asymmetries showed significant associations with disc area asymmetry (P < 0.0001, both) and asymmetry in the presence or absence of physiological cupping, i.e. subjects with physiological cupping in one eye and no cupping in the other (P < 0.0001, both). CONCLUSIONS: We present normative optic disc, cup and VCDR measures and asymmetries among healthy South Indians. We demonstrated the dependence of VCDR on the morphological type of cupping.

Low-luminance contrast stimulation is optimal for early detection of glaucoma using multifocal visual evoked potentials.

PURPOSE: The blue-on-yellow multifocal visual evoked potential (BonY mfVEP) stimulus is more sensitive than the conventional black-and-white pattern-reversal stimulus in identifying early glaucoma. BonY employs pattern-onset stimulation and lower luminance contrast (40%) in addition to color. This study was conducted to elucidate the mechanism responsible for the enhanced performance of the BonY stimulus. METHODS: Multifocal pattern-onset VEPs were recorded in response to BonY, high-luminance contrast achromatic (HLA) and low-luminance contrast achromatic (LLA) stimulations in 30 normal subjects (to construct normative databases) and 23 patients with early glaucoma (mean deviation [MD] < 6 dB). In addition, the specificity of BonY and LLA stimulation was examined in a subset of 25 normal subjects. RESULTS: In normal subjects, LLA mfVEPs had significantly lower amplitudes than did BonY and HLA mfVEPs (P < 0.001), which were not significantly different from each other. In glaucomatous eyes, all three stimuli demonstrated significantly reduced amplitudes in comparison with those of normal eyes. Although the sensitivities of both BonY and LLA in identifying subjective visual field defects were similarly high (93% and 89.7%, respectively), HLA showed only a 79.3% detection rate. BonY and LLA demonstrated significantly higher defect severity scores than did HLA (P < 0.05 for both). Specificities for BonY and LLA were similar (96%). CONCLUSIONS: BonY and LLA mfVEPs performed comparably, and both were significantly better than the HLA mfVEP in identifying early glaucoma. Enhanced performance of BonY stimulation is most likely due to its low-luminance contrast component rather than the pattern-onset mode of presentation or its chromatic properties.

Dichoptic suppression of mfVEP amplitude: effect of retinal eccentricity and simulated unilateral visual impairment.

PURPOSE: To investigate the effect of retinal eccentricity on the phenomenon of dichoptic suppression of the mfVEP amplitude and to examine the relationship between the degree of simulated unilateral visual impairment and the possible release of dichoptic suppression in the contralateral eye. METHOD: Eight subjects with corrected visual acuity (VAc) >6/6 and stereoacuity >60 sec arc underwent monocular and dichoptic pattern-pulse mfVEP. Dichoptic stimulation was repeated with refractively induced blur of one eye with +4-D and +6-D lenses above distance correction. RESULTS: Dichoptic recording resulted in significant reduction of averaged mfVEP amplitude (19.8% ± 4.9%, paired t-test, P = 0.00003). The magnitude of suppression, while statistically significant at all eccentricities, was significantly larger in the central part of the visual field and diminished toward the periphery. Refractive blur, used to simulate visual impairment produced variable degrees of amplitude reduction in the blurred eye and resulted in amplitude increases in the contralateral eye. There was a highly significant correlation between the magnitude of amplitude reduction in the blurred eye and increase in amplitude (i.e., release of dichoptic suppression) in the contralateral eye (r = 0.91, P < 0.0001). CONCLUSIONS: The study demonstrated that dichoptic stimulation results in eccentricity-dependent suppression of mfVEP amplitude. Factors affecting visual performance of one eye (monocular blur) promote the release of dichoptic suppression in the fellow (unaffected) eye. This phenomenon leads to an increase in intereye asymmetry and therefore may improve early detection of ocular diseases, especially monocular pathologic processes.

Remyelination of optic nerve lesions: spatial and temporal factors.

Optic neuritis provides an in vivo model to study demyelination. The effects of myelin loss and recovery can be measured by the latency of the multifocal visual evoked potentials. We investigated whether the extent of initial inflammatory demyelination in optic neuritis correlates with the remyelinating capacity of the optic nerve. Forty subjects with acute unilateral optic neuritis and good visual recovery underwent multifocal visual evoked potentials testing at 1, 3, 6 and 12 months. Average latency changes were analyzed. Extensive latency delay at baseline significantly improved over time with rate of recovery slowed down after 6 months. Magnitude of latency recovery was independent of initial latency delay. Latency recovery ranged from 7 to 17 ms across the whole patient cohort (average = 11.3 (3.1) ms) despite the fact that in a number of cases the baseline latency delay was more than 35-40 ms. Optic nerve lesions tend to remyelinate at a particular rate irrespective of the size of the initial demyelinated zone with smaller lesions accomplishing recovery more completely. The extent of the initial inflammatory demyelination is probably the single most important factor determining completeness of remyelination. The time period favorable to remyelination is likely to be within the first 6 months after the attack.

Outcomes of cataract surgery in a rural and urban south Indian population.

PURPOSE: To assess the visual outcome after cataract surgery in a south Indian population. MATERIALS AND METHODS: Population-based cross-sectional study of subjects aged 40 years or more. Three thousand nine hundred and twenty-four rural subjects from 27 contiguous villages and 3850 urban subjects from five randomly selected divisions were studied. All subjects underwent a comprehensive ophthalmic examination that included visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and dilated retinal examination. STATISTICAL ANALYSIS: Chi square test, t test and multivariate analysis were used. RESULTS: Five hundred and twenty-eight (216 males, 312 females, 781 eyes) rural subjects (13.5%, 95% confidence interval (CI) 12.4% to 14.6%) and 406 (197 males, 209 females, 604 eyes) urban subjects (10.5%, 95% CI 9.6-11.5%) had undergone cataract surgery. Outcome of cataract surgery was defined based on visual acuity. Using best-corrected visual acuity for classification, the single most important cause for visual impairment was cystoid macular edema in the aphakic group and posterior capsule opacification in the pseudophakic group. Aphakia (visual acuity of < 20/60 to

The Chennai glaucoma study: prevalence and risk factors for glaucoma in cataract operated eyes in urban Chennai.

We report the prevalence and risk factors for glaucoma among aphakes and pseudophakes in 3850 subjects who participated in a population-based study in urban south India. The subjects underwent an ophthalmic examination including applanation tonometry, gonioscopy, optic disc evaluation and frequency doubling perimetry. Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria. Thirty eight, 15 aphakes and 23 pseudophakes (0.99% of 3850 subjects) of the 406 persons who had undergone cataract surgery were diagnosed with glaucoma. Aphakes/pseudophakes were at higher risk of glaucoma as compared to the phakic population (Odds Ratio: 2.71, 95% CI: 1. 94, 3.38, p=0.001). On multivariate analysis, older age and higher intra ocular pressure were risk factors for glaucoma. Blindness attributable to glaucoma was detected in 20% of aphakic and 4.3% of pseudophakic eyes. Glaucoma was a significant cause of morbidity in those who had undergone cataract surgery in this urban population.

Central corneal thickness in adult South Indians: the Chennai Glaucoma Study.

OBJECTIVE: To evaluate the characteristics of central corneal thickness (CCT) and its association with age, gender, and intraocular pressure in rural and urban South Indian populations. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Seven thousand seven hundred seventy-four subjects (rural-to-urban ratio, 3924:3850) aged 40 years and older were examined at a dedicated facility in the base hospital. INTERVENTION: All subjects underwent a complete ophthalmic examination that included CCT measurements with an ultrasonic pachymeter and applanation tonometry. MAIN OUTCOME MEASURES: Central corneal thickness. RESULTS: Of the 7774 subjects examined, 974 had undergone cataract surgery and were excluded. The remaining 6800 were bilaterally phakic, of which 46 were excluded (17 glaucoma subjects receiving treatment, 12 with corneal pathologic features and 17 with incomplete data) and 6754 subjects data were analyzed. The mean CCT for the population was 511.4+/-33.5 microm, and CCT in males (515.6+/-33.8 microm) was significantly (P = 0.0001) greater than females (508.0+/-32.8 microm). The CCT was significantly greater (by 18 microm) in the urban population and decreased with age in both genders (P<0.0001). The decrease per decade was 4.34 microm (95% confidence interval [CI], 3.24-5.44) in the rural population and 2.41 microm (95% CI, 1.25-3.53) in the urban population. A 100-microm increase in CCT was associated with a 1.96-mmHg increase in intraocular pressure in the rural population, versus 2.45 mmHg for every 100 microm in the urban population. CONCLUSIONS: In this population-based study, females and subjects living in a rural area had thinner corneas. A negative association with age and a positive association with intraocular pressure were seen. These findings will have implications in the diagnosis and management of glaucoma in this population. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Interrelationship of optical coherence tomography and multifocal visual-evoked potentials after optic neuritis.

PURPOSE: Acute optic neuritis (ON) is often followed by recovery of visual function. Although this recovery is mainly attributable to resolution of the acute inflammation, the redistribution of ion channels along the demyelinated membrane, and subsequent remyelination, part of it may be the result of neural plasticity. In the present study, the interrelationship was examined between structural (retinal nerve fiber layer [RNFL] thickness) and functional (amplitude of multifocal visual evoked potentials [mfVEPs]) measures of the integrity of the visual pathway in the postacute stage of ON, to determine whether there was any evidence of ongoing neural reorganization. METHODS: Twenty-five subjects with acute unilateral ON underwent serial RNFL thickness measurement and mfVEP recording. The inter-eye asymmetry of both measures was analyzed. In the period between 6 and 12 months, the subjects were considered free of optic disc edema, and that period was used to analyze the structure-function relationship. Twenty control subjects were also examined. RESULTS: There were significant but opposite changes in RNFL thickness and mfVEP amplitude. The average asymmetry of RNFL thickness between affected and fellow eyes increased from 17.5 +/- 11.5 to 21.1 +/- 12.8 microm (P = 0.0003), indicating progressive axonal loss, whereas mfVEP amplitude asymmetry decreased from 46.6 +/- 32.4 to 38.3 +/- 31.1 nV (P = 0.0015), indicating continuous functional recovery. In comparison to the 6-month results, the mfVEP amplitude in the ON eye improved by 17.8%, whereas RNFL thickness decreased by 20.8%. The result remained unchanged regardless of the degree of optic nerve remyelination. CONCLUSIONS: The finding of structural-functional discrepancy at the postinflammatory stage may support the concept that neural plasticity contributes to functional recovery after acute ON.

Identifying preperimetric functional loss in glaucoma: a blue-on-yellow multifocal visual evoked potentials study.

PURPOSE: To determine the ability of blue-on-yellow multifocal visual evoked potentials (BonY mfVEP) to identify functional loss in preperimetric glaucoma. DESIGN: Prospective case series. PARTICIPANTS: Thirty patients with glaucomatous optic discs and normal standard visual fields. METHODS: All patients underwent BonY mfVEP, dilated optic disc stereophotography, and optical coherence tomography (Fast RNFL protocol). Optic disc photographs were assessed by 2 independent examiners in a masked fashion. MAIN OUTCOME MEASURES: The mfVEP amplitude asymmetry and latency values were analyzed and compared topographically with findings of disc assessment. Average retinal nerve fiber layer (RNFL) thickness, RNFL asymmetry, and sectors with RNFL thinning were compared between patients with and without mfVEP defects. RESULTS: Fourteen (46.7%) patients demonstrated significant abnormality on amplitude asymmetry deviation plots of BonY mfVEP. In all 14 cases, the defect was monocular and corresponded to the eye with the worse disc. In 13 of 14 patients, the defect also corresponded to the location of the worst affected rim. Average RNFL thickness of eyes with mfVEP defects was 81.2+/-9.9 microm, significantly lower than that of patients without defects (90+/-10.5 microm; P = 0.035). Mean asymmetry of RNFL (better minus worse eye) also was significantly higher for patients with mfVEP defects compared with those without such defects (9.0+/-6.4 microm vs. 3.0+/-7 microm; P = 0.03). Average latency of both eyes of glaucomatous patients was delayed compared with that of controls, with no difference in latency between worse and better eyes of glaucoma patients. There was no association of latency delay with either the location of disc changes or mfVEP amplitude defects. CONCLUSIONS: Amplitude asymmetry of the BonY mfVEP seems to be a promising tool to identify functional loss in preperimetric glaucoma. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.