Biomedical subjects

T J Naduvilath

Publications and source records attributed to T J Naduvilath.

At least 19 recordsLinked to original sources

PubMed2000

Sensitivity of Swedish interactive threshold algorithm compared with standard full threshold algorithm in Humphrey visual field testing.

OBJECTIVE: To compare the sensitivity of Swedish interactive threshold algorithm (SITA) strategies with the standard full threshold algorithm in the Humphrey Field Analyzer. DESIGN: Observational case series. PARTICIPANTS: Forty-eight glaucoma patients who were experienced in automated perimetry. TESTING: Central field testing was performed with the 30-2 program using standard full threshold (SFT), SITA standard (SS), and SITA fast (SF) strategies. All three tests were carried out on each of four different days in a span of 4 weeks. MAIN OUTCOME MEASURES: Sensitivity, repeatability, time saved, and the extent of defect in the SITA strategies were compared with those of the SFT. RESULTS: The sensitivity of SS and SF were 95.12% and 92.68%, respectively. The time saved in SS and SF was 53.12+/-9.51% and 70.69+/-8.81%, respectively. The repeatability as assessed by intraclass correlation showed excellent repeatability for the SFT and SS strategies and excellent to poor repeatability with the SF strategy. With increasing mean deviation, the defects (significant at P<0.5%) in the pattern deviation plots tended to be more in the SITA strategies as compared with SFT. CONCLUSIONS: Swedish interactive threshold algorithm strategies have good sensitivity and are significantly faster as compared with the standard threshold algorithm. The repeatability of the SFT and SS strategies are excellent, whereas that of the SF strategy is variable.

Algorithms↗

PubMed2000

Use of ultrasound biomicroscopic evaluation in preoperative planning of penetrating keratoplasty.

PURPOSE: To evaluate the use of ultrasound biomicroscopy (UBM) in examining the status of anterior-segment structures in eyes with corneal opacification. METHODS: Evaluation with UBM was performed between 1 and 2 weeks before surgery in 21 patients (21 eyes) with corneal opacities who were scheduled for penetrating keratoplasty. UBM findings were correlated with the findings noted during penetrating keratoplasty. The efficacy of UBM evaluation was calculated in terms of positive and negative predictive values (PPVs and NPVs) for the presence or absence of each finding. RESULTS: Seventeen eyes had either aphakic or pseudophakic bullous keratopathy (ABK or PBK). UBM findings of anterior synechiae, peripheral anterior synechiae, posterior synechiae, peripheral and sector iridectomies positively correlated with those observed during surgery in five (55.6%) of nine locations, 19 (73.1%) of 26 locations, 12 (80%) of 15 locations, eight (88.9%) of nine locations) and six (85.7%) of seven locations, respectively. The NPVs for these findings were 100%, six (54.5%) of 11 locations), 10 (71.4%) of 14 locations, 12 (100%) of 12 locations, and 14 (100%) of 14 locations, respectively. Correlation for findings pertaining to the posterior capsule (PC) were presence of PC/PC remnants [PPV, 13 (92.9%) of 14 locations; NPV, two (66.7%) of three locations], presence of central PC tears [PPV, two (66.7%) of three locations], intactness of PC [PPV, six (85.7%) of seven locations], and PC thickening [PPV, 13 (81.25%) of 16 locations; NPV, four (100%) of four locations]. For vitreous in the anterior chamber, the PPV was eight (100%) of eight locations, and NPV was 12 (92.3%) of 13 locations. Pseudophakos-related information in eyes with PBK showed a PPV of 100% for presence, centration, and anatomic location (seven of seven, four of four, and seven of seven locations, respectively). CONCLUSION: In eyes with corneal opacity, UBM determines the status of various anterior-segment structures. It is thus a useful adjunct in the preoperative planning and prognostication of patients requiring penetrating keratoplasty.

Anterior Eye Segment↗

PubMed2000

Bacterial colonization of disposable soft contact lenses is greater during corneal infiltrative events than during asymptomatic extended lens wear.

Microorganisms, especially gram-negative bacteria, are considered to play a role in the etiology of certain corneal infiltrative events (CIEs) observed during soft contact lens wear. This study explored the possibility of microbial colonization of soft contact lenses as a risk factor leading to CIEs. In a clinical trial conducted from March 1993 to January 1996, 330 subjects wore disposable soft contact lenses on a 6-night extended-wear and disposal schedule. During this period, 4,321 lenses (118 during CIEs; 4,203 during asymptomatic lens wear) were recovered aseptically and analyzed for microbial colonization. A greater percentage of lenses were free from microbial colonization during asymptomatic wear than during CIEs (42 versus 23%; P < 0.0001). The incidence of gram-positive bacteria, gram-negative bacteria and fungi was greater during CIEs than during asymptomatic lens wear (P < 0.05). During asymptomatic lens wear, gram-positive bacteria were isolated most frequently and were usually normal external ocular microbiota. Of the gram-positive bacteria, the incidence of Streptococcus pneumoniae was greater during CIE than during asymptomatic wear (7.6 versus 0.6%; P < 0. 0001). While gram-negative bacteria were seen in few cases during asymptomatic wear, their incidence during CIE in comparison to asymptomatic wear was substantial and significant (23.7 versus 3.8%; P < 0.0001). Also, the level of colonization was high. Of CIEs, events of microbial keratitis, contact lens acute red eye, and asymptomatic infiltrative keratitis were associated with lens colonization with gram-negative bacteria or S. pneumoniae. Colonization of soft contact lenses with pathogenic bacteria, especially gram-negative bacteria and S. pneumoniae, appears to be a significant risk factor leading to CIE.

Bacteria↗

PubMed2000

Utilisation of eyecare services in an urban population in southern India: the Andhra Pradesh eye disease study.

AIM: To assess utilisation of eyecare services by people with visual impairment <6/18 or equivalent visual field loss in the better eye in the urban population of Hyderabad in southern India. METHODS: 2522 subjects of all ages, representative of the population of Hyderabad city, underwent a detailed interview and dilated examination as part of the population based Andhra Pradesh eye disease study. Subjects more than 15 years of age were interviewed regarding the use of eyecare services. RESULTS: Of 250 subjects with presenting distance visual acuity <6/18 or equivalent visual field loss in the better eye, information on utilisation of eyecare services was available for 229 (91.6%). Of these 229 subjects, 44 (19%) had visual acuity <6/60 or equivalent visual field loss in the better eye, and 202 (88.2%) had noticed decrease in vision over the past 5 years. Multivariate analysis showed that this decrease in vision was noticed significantly less by subjects with refractive error as the cause of visual impairment (odds ratio 0.34, 95% confidence interval 0.12-0.93). Of the 229 subjects who were visually impaired, 108 (59%) did not seek treatment. Multivariate analysis revealed that the odds for seeking treatment were significantly lower for Hindus than Muslims (odds ratio 0.53, 95% confidence interval 0.28-0.98). The reasons for not seeking treatment could be classified as personal (49.5%), economic (30.8%), and social (19.6%). CONCLUSION: A large proportion of subjects with visual impairment in this urban population in India did not seek treatment even after noticing decrease in vision. Projecting these data to the 155 million urban population >15 years of age in India, there may be 4.9 million (95% confidence interval 4.3-5.5 million) people in urban India who are not seeking treatment for their visual impairment even after noticing decrease in vision. These data suggest that efforts have to be made to better understand the reasons for this phenomenon so that optimal utilisation of the available eyecare services in urban India can be planned.

Adolescent↗

PubMed2000

Sample size for ophthalmology studies.

Knowledge and the usage of actual sample size formulae are a necessity as validity of the inferences from research studies is often dependent on this. This paper explains how sample sizes are calculated. The concept of sampling variation is explained to emphasize the need for its proper calculation. Sample size formulae are explained with examples to provide researchers with a means of calculating the sample sizes for the commonly used study designs. Ophthalmic data are used as examples. It is perceived that this will improve the quality of inferences drawn from ophthalmic research studies.

Humans↗

PubMed1999

Population-based assessment of the outcome of cataract surgery in an urban population in southern India.

PURPOSE: To assess the outcome of cataract surgery in an urban population in southern India. METHODS: As part of a population-based cross-sectional epidemiologic study, the Andhra Pradesh Eye Disease Study, 2,522 people of all ages, including 1,399 individuals 30 years of age or older, from 24 clusters representative of the population of Hyderabad in southern India underwent a detailed interview and ocular evaluation including logarithm of minimal angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, dilation, cataract grading, aphakia/pseudophakia status, and stereoscopic fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were performed when indicated by standardized criteria. Very poor outcome in an eye that had undergone cataract surgery was defined as presenting distance visual acuity worse than 20/200, and poor outcome was defined as visual acuity worse than 20/60 to 20/200. RESULTS: In subjects 50 years of age or older, after adjustment for age and sex distribution, the rate of having had cataract surgery in one or both eyes was 14.6% (95% confidence interval [CI], 11.4% to 17.8%). Of 131 eyes (91 subjects) that had undergone cataract surgery, 28 (21.4%; 95% CI, 14.4% to 28.4%) had very poor outcome and another 40 (30.5%; 95% CI, 22.6% to 38.4%) had poor outcome. The very poor outcome in 20 (71.4%) of 28 eyes and poor outcome in 23 (57.5%) of 40 eyes could be attributed to surgery-related causes or inadequate refractive correction. With multivariate analysis, very poor outcome as a result of surgery-related causes or inadequate refractive correction was more likely to be associated with intracapsular cataract extraction than with extracapsular cataract extraction (odds ratio, 9.34; 95% CI, 2.49 to 35.06) in subjects belonging to the lowest socioeconomic status (odds ratio, 4.92; 95% CI, 1.16 to 20.93) and with date of surgery 3 or fewer years before the survey than with more than 3 years (odds ratio, 4.52; 95% CI, 1.33 to 15.39). Also, very poor or poor outcome as a result of surgery-related causes or inadequate refractive correction was associated with women (odds ratio, 2.55; 95% CI, 1.06 to 6.16). CONCLUSIONS: The very high rate of very poor and poor visual outcome, predominantly as a result of surgery-related causes and inadequate refractive correction, in this urban population of India suggests that more attention is needed to improve the visual outcome of cataract surgery. In order to deal with cataract-related visual impairment in India, as much emphasis on surgical quality, refractive correction, and follow-up care is necessary as on the number of surgeries.

Adult↗

PubMed1999

Burden of moderate visual impairment in an urban population in southern India.

OBJECTIVE: To assess the prevalence and causes of moderate visual impairment in an urban population in southern India. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 2522 (85.4% of the eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city. TESTING: The eligible subjects underwent a detailed ocular evaluation, including logarithm of the minimum angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, cataract grading, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated by standardized criteria. MAIN OUTCOME MEASURE: Moderate visual impairment was defined as presenting distance visual acuity less than 20/40 to 20/200 or visual field loss by predefined standardized conservative criteria in the better eye. RESULTS: In addition to the 1% prevalence of blindness in this sample reported earlier, moderate visual impairment was present in 303 subjects, an age-gender-adjusted prevalence of 7.2% (95% confidence interval [CI], 4.5%-9.9%; design effect, 2.7). The major cause of moderate visual impairment was refractive error (59.4%, 95% CI, 52.3%-66.5%) followed by cataract (25.3%, 95% CI, 19%-31.6%). Multivariate analysis showed that the prevalence of moderate visual impairment was significantly higher in those 40 years of age or older (odds ratio, 10.9; 95% CI, 8-15) and females (odds ratio, 1.89; 95% CI, 1.41-2.53) and lower in those belonging to the highest socioeconomic status (odds ratio, 0.27; 95% CI, 0.14-0.51). However, because of the pyramidal age distribution of the population, 38.1% of the total moderate visual impairment was present in those younger than 40 years of age. The proportion of moderate visual impairment caused by refractive error was higher in the younger than in the older age groups (P < 0.0001). CONCLUSIONS: Projecting the results to the 26.5% urban population of India, there would be 18.4 million (95% CI, 11.5-25.2 million) persons with moderate visual impairment in urban India alone. Refractive error was the major cause of moderate visual impairment in the population studied. The absolute proportion of moderate visual impairment in those younger than 40 years of age was considerable. The eyecare policy of India, apart from dealing with blindness, should address the issue of the relatively easily treatable uncorrected refractive error as the cause of moderate visual impairment in an estimated 10.9 million persons in urban India.

Adolescent↗

PubMed1999

Heparin-surface-modified intraocular lenses in pediatric cataract surgery: prospective randomized study.

PURPOSE: To evaluate the performance of heparin-surface-modified (HSM) intraocular lenses (IOLs) in pediatric eyes after cataract surgery. SETTING: L.V. Prasad Eye Institute, Hyderabad, India. METHODS: This prospective, randomized, double-masked, controlled clinical trial comprised 90 children aged 2 to 14 years with cataract. The patients were consecutively randomized to receive an HSM (Group 1) or an unmodified (Group 2) poly(methyl methacrylate) (PMMA) IOL. Extracapsular cataract extraction (ECCE) with IOL implantation was performed in children 8 years and older and ECCE with primary posterior capsulotomy, anterior vitrectomy, and IOL implantation in children younger than 8 years. Outcome parameters were inflammatory cell deposits on the IOL surface, posterior synechias, and anterior chamber reaction. RESULTS: Follow-up data were available for 73, 70, 60, and 68 patients at 1 week, 1 month, 3 months, and 6 months, respectively. Significantly fewer cell deposits were noted in Group 1 at 1, 3, and 6 months (P < .001). Synechia formation and anterior chamber reaction were comparable in the 2 groups. CONCLUSION: The lower incidence of inflammatory cell deposit formation in eyes with HSM PMMA IOLs indicates that these IOLs have greater bicompatibility than unmodified IOLs in pediatric cataract surgery.

Adolescent↗

PubMed1999

Demography and prognostic factors of ocular injuries in South India.

PURPOSE: To evaluate the extent of visual recovery after multi-disciplinary approach of treatment in serious ocular injuries; to determine the prognostic factors associated with poor final visual outcome and suggest adequate precautionary measures. METHODS: A retrospective analysis of 325 consecutive patients with direct ocular trauma who were examined and treated at a tertiary eye care centre in South India over a 3-year period was undertaken. RESULTS: Males (86.8%) outnumbered the females (13.2%) and children (< 16 years) constituted 46.8% of the total affected population. Anterior segment was involved in 51.1%, the posterior segment in 8.9% and both anterior and posterior segments were involved in 31.4% of patients. Prompt and meticulous surgical treatment restored useful vision (better than or equal to 6/18) in 60.5% of patients. Post-treatment, a reduction in blindness and visual impairment rates in the affected eye with respect to WHO classification was 66.7 and 54.1% respectively (P < 0.0001). Two eyes needed prompt enucleation. The factors associated with visual impairment (visual acuity less than 6/18) were poor initial visual acuity, full chamber hyphema, endophthalmitis, retinal detachment, and vitreous haemorrhage. CONCLUSIONS: Direct ocular trauma remains an important potentially preventable cause of ocular morbidity, but the advent of modern surgical techniques can often restore useful vision in such situations. Mandatory use of protective eye wear at work, public health education including awareness on the part of parents to the potential dangers of some childrens' toys can to an extent help reduce ocular morbidity due to direct ocular trauma.

Accidents, Home↗

PubMed1999

Colonization of hydrogel lenses with Streptococcus pneumoniae: risk of development of corneal infiltrates.

PURPOSE: To report the association between colonization of contact lenses with Streptococcus pneumoniae and the observation of corneal infiltrative events in a group of patients wearing disposable hydrogel lenses on an extended-wear schedule. METHODS: In a prospective clinical trial, 330 patients wore disposable hydrogels on a 6-night extended-wear and replacement schedule. The contact lens, lid, and conjunctival microbiota of these subjects was analyzed at frequent intervals and at the time of an adverse event. RESULTS: Streptococcus pneumoniae was an uncommon isolate and was recovered from only one of the 3,763 conjunctival samples, five (0.1%) of the 3,764 lid samples, and 33 (0.8%) of the 4,315 contact lens samples. Of the 33 lens samples, 10 (30%) were associated with corneal infiltrative events. Many of the events were mild inflammatory responses and resolved rapidly on discontinuation of lens wear. The presence of S. pneumoniae on the contact lens was associated with a significant risk of development of corneal infiltrates (odds ratio, 3.0; p = 0.0227, logistic-regression analysis). CONCLUSIONS: Presence of S. pneumoniae on hydrogel lenses is a significant risk factor for the development of corneal infiltrates.

Adolescent↗

PubMed1999

Population based assessment of diabetic retinopathy in an urban population in southern India.

AIM: To assess the prevalence of diabetic retinopathy and the visual impairment caused by it in an urban population in southern India in order to determine its public health significance. METHODS: 2522 subjects (85.4% of those eligible), a representative sample of the population of Hyderabad city in southern India, underwent interview and detailed dilated eye examination during 1996-7 as part of the Andhra Pradesh Eye Disease Study. RESULTS: 124 subjects, all >/=30 years old, reported that they had diabetes, an age-sex adjusted prevalence of 7.82% (95% confidence interval (CI) 5.76-9.88%) in this age group. Diabetes was diagnosed at age >/=30 years in all but two subjects. The duration since diagnosis of diabetes was <10 years in 75.6% and >/=15 years in 6.7%. Diabetic retinopathy was present in 28 subjects, 1.78% (95% CI 1.09-2.48%) of those >/=30 years old. Most of the diabetic retinopathy was of the mild (50%) or moderate (39.3%) non-proliferative type; one subject (3.6%) had proliferative retinopathy. Multiple logistic regression revealed that the odds of having diabetic retinopathy were significantly higher in those >/=50 years than in those 30-49 years old (odds ratio 7.78, 95% CI 2.92-20. 73). Three subjects had visual impairment between 6/12 and 6/38 in either eye due to diabetic retinopathy, 0.19% (95% CI 0-0.41%) of those >/=30 years old. CONCLUSION: Visual impairment due to diabetic retinopathy was relatively uncommon in this urban Indian population in 1996-7. However, this could change in the near future with an increase in duration of diabetes because of the anticipated aging of India's population and the recent suggestion of increase in diabetes prevalence in urban India, and therefore should be monitored.

Adult↗

PubMed1999

Intravitreal dexamethasone in exogenous bacterial endophthalmitis: results of a prospective randomised study.

AIM: To evaluate the efficacy of intravitreal dexamethasone co-administered with intravitreal antibiotics along with vitrectomy in the management of exogenous bacterial endophthalmitis. METHODS: In a prospective randomised clinical trial, 63 patients (63 eyes) with suspected bacterial endophthalmitis (postoperative and post-traumatic) were treated with vitrectomy and intravitreal antibiotics and randomised to intravitreal dexamethasone (IOAB with = 29 eyes) and no dexamethasone (IOAB without = 34 eyes). Inflammation score (IS) and visual acuity were measured by two masked observers before surgery, and at 1, 4, and 12 weeks after surgery in both the groups. RESULTS: There was significant reduction (p <0.0001) in IS at 1, 4, and 12 weeks after the surgery in the "IOAB with" group; there was temporary but significant increase (p <0.01) in IS at 1 week in the "IOAB without" group, before decline (p <0.001) of IS at 4 and 12 weeks. The magnitude and relative percentage change in IS between the two groups were found to be significant at 1 (p <0.0001), and 4 (p <0.01) weeks, and not at 12 weeks. The visual acuity at 12 weeks was comparable in both the IOAB with and IOAB without groups. CONCLUSION: Intravitreal dexamethasone helps in early reduction of inflammation in exogenous bacterial endophthalmitis, but has no independent influence on the visual outcome. In selected patients with endophthalmitis where oral corticosteroids cannot be given for medical reasons intravitreal corticosteroids could be beneficial; in other situations they could be complementary to oral corticosteroid therapy.

Administration, Topical↗

PubMed1999

Surgical results and complications of mitomycin C-augmented trabeculectomy in refractory developmental glaucoma.

BACKGROUND AND OBJECTIVE: To evaluate the surgical results and complications of mitomycin C-augmented trabeculectomy in refractory developmental glaucoma. PATIENTS AND METHODS: The authors reviewed the charts of all patients of refractory developmental glaucoma who underwent mitomycin C-augmented trabeculectomy (0.4 mg/ml for 3 minutes) between September 1990 and August 1995. Thirty-eight eyes of 29 patients were included in the study; 34 eyes (89.5%) had refractory primary congenital glaucoma with documented failure of primary surgery, 2 eyes (5.3%) had Axenfeld-Rieger syndrome and 2 eyes (5.3%) had aniridia. The main outcome measures in this study were preoperative and postoperative intraocular pressures (IOPs),visual acuities, bleb characteristics, success rate, time of surgical failure, and complications. RESULTS: The IOP (mean +/- SD) reduced from a preoperative level of 32.6 +/- 11.8 mm Hg to 12.3 +/- 7.3 mm Hg (P <0.0001) with the percentage reduction in IOP being 56%. Kaplan-Meier survival analysis showed that the success probability at 18 months was 65%, which was maintained till 30 months of follow-up. The bleb was characterized by its large, elevated, avascular, transparent appearance in all the eyes. There were no intraoperative complications. The postoperative complications included hyphema (absorbed one week) in 8 eyes (21%), uncontrolled IOP in 8 eyes (21%), shallow anterior chamber in 3 eyes (7.9%), hypotony without visual loss in one eye (2.6%) and retinal detachment in 2 eyes (5.2%) which was surgically repaired successfully. Visual acuity was maintained in all cases after surgery. None of the patients developed mitomycin-C related late bleb-leakage or endophthalmitis. CONCLUSION: Treatment of refractory developmental glaucoma with mitomycin C-augmented trabeculectomy is effective and safe with an acceptable rate of complications.

Adolescent↗

PubMed1999

Refractive errors in an urban population in Southern India: the Andhra Pradesh Eye Disease Study.

PURPOSE: To assess the prevalence, distribution, and demographic associations of refractive error in an urban population in southern India. METHODS: Two thousand five hundred twenty-two subjects of all ages, representative of the Hyderabad population, were examined in the population-based Andhra Pradesh Eye Disease Study. Objective and subjective refraction was attempted on subjects >15 years of age with presenting distance and/or near visual acuity worse than 20/20 in either eye. Refraction under cycloplegia was attempted on all subjects < or =15 years of age. Spherical equivalent >0.50 D in the worse eye was considered as refractive error. Data on objective refraction under cycloplegia were analyzed for subjects < or =15 years and on subjective refraction were analyzed for subjects >15 years of age. RESULTS: Data on refractive error were available for 2,321 (92.0%) subjects. In subjects < or =15 years of age, age-gender-adjusted prevalence of myopia was 4.44% (95% confidence interval [CI], 2.14%-6.75%), which was higher in those 10 to 15 years of age (odds ratio, 2.75; 95% CI, 1.25-6.02), of hyperopia 59.37% (95% CI, 44.65%-74.09%), and of astigmatism 6.93% (95% CI, 4.90%-8.97%). In subjects >15 years of age, age-gender-adjusted prevalence of myopia was 19.39% (95% CI, 16.54%-22.24%), of hyperopia 9.83% (95% CI, 6.21%-13.45%), and of astigmatism 12.94% (95% CI, 10.80%-15.07%). With multivariate analysis, myopia was significantly higher in subjects with Lens Opacity Classification System HI nuclear cataract grade > or =3.5 (odds ratio, 9.10; 95% CI, 5.15-16.09), and in subjects with education of class 11 or higher (odds ratio, 1.80; 95% CI, 1.18-2.74); hyperopia was significantly higher in subjects > or =30 years of age compared with those 16 to 29 years of age (odds ratio, 37.26; 95% CI, 11.84-117.19), in females (odds ratio, 1.86; 95% CI, 1.33-2.61), and in subjects belonging to middle and upper socioeconomic strata (odds ratio, 2.10; 95% CI, 1.09-4.03); and astigmatism was significantly higher in subjects > or =40 years of age (odds ratio, 3.00; 95% CI, 2.23- 4.03) and in those with education of college level or higher (odds ratio, 1.73; 95% CI, 1.07-2.81). CONCLUSIONS: These population-based data on distribution and demographic associations of refractive error could enable planning of eye-care services to reduce visual impairment caused by refractive error. If these data are extrapolated to the 255 million urban population of India, among those >15 years of age an estimated 30 million people would have myopia, 15.2 million hyperopia, and 4.1 million astigmatism not concurrent with myopia or hyperopia; in addition, based on refraction under cycloplegia, 4.4 million children would have myopia and 2.5 million astigmatism not concurrent with myopia or hyperopia.

Adolescent↗

PubMed1999

Optic disc size in ocular hypertension.

PURPOSE: To study the optic disc size in eyes with ocular hypertension (OHT) in comparison to primary open-angle glaucoma (POAG) and normals. METHODS: Optic disc photographs obtained with the Nidek 3dx NM camera were digitized (Nikon coolscan) and disc area calculated using Littmann correction in a randomly chosen eye of 28 OHT, 42 POAG and 30 normal subjects. OHT was defined as increased intraocular pressure with no disc or field changes suggestive of glaucoma with open angles. RESULTS: The optic disc area in OHT was 9.47 +/- 1.09 mm2; 12.27 +/- 2.87 mm2 in POAG; and 12.11 +/- 2.83 mm2 in normal individuals. CONCLUSION: Using magnification corrected morphometry and the criteria for OHT diagnosis, the optic disc area in OHT was significantly smaller (p < 0.0001) in POAG and normals.

Glaucoma, Open-Angle↗

PubMed1998

Is current eye-care-policy focus almost exclusively on cataract adequate to deal with blindness in India?

BACKGROUND: India's National Programme for Control of Blindness focuses almost exclusively on cataract, based on a national survey done in the 1980s which reported that cataract caused 80% of the blindness in India. No current population-based data on the causes of blindness in India are available. We assessed the rate and causes of blindness in an urban population in southern India. METHODS: We selected 2954 participants by stratified, random, cluster, systematic sampling from Hyderabad city. Eligible participants were interviewed and given a detailed ocular assessment, including visual acuity, refraction, slitlamp biomicroscopy, applanation intraocular pressure, gonioscopy, dilatation, grading of cataract, stereoscopic fundus assessment, and automated-threshold visual fields. FINDINGS: 2522 participants, including 1399 aged 30 years or more, were assessed. 49 participants (all aged > or =30 years) were blind (presenting distance visual acuity <6/60 or central visual field <200 in the better eye). The rate of blindness among those aged 30 years or more, adjusted for age and sex, was 3.08% ([95% CI 1.95-4.21]). Causes included cataract (29.7%), retinal disease (17.1%), corneal disease (15.4%), refractive error (12.5%), glaucoma (12.1%), and optic atrophy (11.0%). 15.7% of the blindness caused by visual-field constriction would have been missed without visual-field examination. Also without visual-field and detailed dilated-fundus assessments, blindness attributed to cataract would have been overestimated by up to 75.8%. If the use of cataract surgery in this urban population was half that found in this study, which simulates the situation in rural India, cataract would have caused 51.8% (39.4-64.2) of blindness, significantly less than the 80% accepted by current policy. INTERPRETATION: Much of the blindness in this Indian population was due to non-cataract causes. The previous national survey did not include detailed dilated-fundus assessment and visual-field examination which could have led to overestimation of cataract as a cause of blindness in India. Policy-makers in India should encourage well-designed population-based epidemiological studies from which to develop a comprehensive long-term policy on blindness in addition to dealing with cataract.

Adult↗

PubMed1998

Surgical results of combined trabeculotomy-trabeculectomy for developmental glaucoma.

OBJECTIVE: The purpose of the study was to evaluate the surgical outcome of combined trabeculotomy-trabeculectomy in different types of primary developmental glaucomas. DESIGN: A retrospective review of all cases of primary developmental glaucomas that underwent primary combined trabeculotomy-trabeculectomy between August 1990 and September 1995, with a minimum follow-up of 6 months, was performed. PARTICIPANTS: One hundred and eighty-two eyes of 120 patients were included in this study; 122 (67%) eyes had congenital glaucoma; 22 (12.1%) eyes had infantile glaucoma; and 38 (20.9%) eyes had juvenile glaucoma. INTERVENTION: Primary combined trabeculotomy-trabeculectomy was the chosen intervention. MAIN OUTCOME MEASURES: Preoperative and postoperative intraocular pressures, visual acuities, success rate, corneal clarity and diameters, bleb characteristics, time of surgical failure, and complications were the main outcome measures. RESULTS: Intraocular pressure (mean +/- SD) reduced from a preoperative level of 26.5 +/- 8.3 mmHg; 30.3 +/- 9.9 mmHg; and 31.8 +/- 11.5 mmHg to 13.1 +/- 5.8 mmHg; 13.7 +/- 4.4 mmHg; and 13.3 +/- 6.0 mmHg in the congenital, infantile, and juvenile types of developmental glaucomas, respectively. Kaplan-Meier survival analysis showed that the success probability at 6 months was 94.4% +/- 2.3%; 90.9% +/- 6.1%; and 81.0% +/- 7.3% in the three groups, respectively. The success probability of patients with juvenile glaucoma was significantly lower than it was for those with congenital glaucoma (P = 0.0393). Of 182 eyes, 105 (57.7%) eyes had corneal edema at presentation. Eighty-one (79%) of 105 eyes had complete clearance of corneal edema postoperatively (P < 0.0001). The follow-up period ranged from 6 months to 48 months (mean, 10.7 +/- 12.0 months). There were no sight-threatening intraoperative and postoperative complications in any patient. CONCLUSIONS: Primary combined trabeculotomy-trabeculectomy is safe, effective, and sufficiently predictable to be considered the first choice of surgical treatment in primary congenital glaucoma with corneal edema. Juvenile glaucoma has the worst prognosis, and infantile glaucoma has a better prognosis than does juvenile glaucoma.

Cornea↗

PubMed1998

Causes of corneal graft failure in India.

The success of corneal grafting in visual rehabilitation of the corneal blind in India depends on survival of the grafts. Understanding the causes of graft failure may help reduce the risk of failure. We studied these causes in a series of 638 graft failures at our institution. Multivariate logistic regression analysis was used to evaluate the association of particular causes of graft failure with indications for grafting, socioeconomic status, age, sex, host corneal vascularization, donor corneal quality, and experience of surgeon. The major causes of graft failure were allograft rejection (29.2%), increased intraocular pressure (16.9%), infection excluding endophthalmitis (15.4%), and surface problems (12.7%). The odds of infection causing graft failure were significantly higher in patients of lower socioeconomic status (odds ratio 2.45, 95% CI 1.45-4.15). Surface problems as a cause of graft failure was significantly associated with grafts done for corneal scarring or for regrafts (odds ratio 3.36, 95% CI 1.80-6.30). Increased intraocular pressure as a cause of graft failure had significant association with grafts done for aphakic or pseudophakic bullous keratopathy, congenital conditions or glaucoma, or regrafts (odds ratio 2.19, 95% CI 1.25-3.84). Corneal dystrophy was the indication for grafting in 12 of the 13 cases of graft failure due to recurrence of host disease. Surface problems, increased intraocular pressure, and infection are modifiable risk factors that are more likely to cause graft failure in certain categories of patients in India. Knowledge about these associations can be helpful in looking for and aggressively treating these modifiable risk factors in the at-risk categories of corneal graft patients. This can possibly reduce the chance of graft failure.

Child↗