Vimla Menon

All India Institute of Medical Sciences, New Dilli, NCT, India

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Publications (50)52.05 Total impact

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    ABSTRACT: To evaluate structural changes in the retina and correlate those with visual function measurements in patients with Parkinson disease (PD). A cross-sectional comparative study of 20 patients with PD and 20 age-matched healthy controls was conducted. Visual acuity, color vision, contrast sensitivity, visual fields, pattern visual-evoked response (VER), and multifocal electroretinogram were recorded to determine functional change, whereas structural changes were evaluated with retinal nerve fiber layer (RNFL) thickness, macular thickness, macular volume, and ganglion cell-inner plexiform layer complex (GCL-IPL) thickness using spectral domain ocular coherence tomography (SD-OCT). PD patients ranged from Stage 1-3, with median Stage 2 (Hoehn and Yahr Classification) with mean Unified Parkinson Disease Rating Scale III score of 19 ± 10.42, and average disease duration of 5.8 ± 2.78 years. Visual acuity, color vision, and visual fields were unaffected but contrast sensitivity was significantly worse than controls (P < 0.001). Multifocal electroretinogram values in the central 2° field revealed decreased foveal electrical activity, with increased pattern VER amplitude and latency. Significant RNFL thinning was observed in the average RNFL (P = 0.033), superior (P = 0.018), and temporal (P = 0.036) quadrants. Significant ganglion cell layer loss was captured on SD-OCT with average, minimum GCL-IPL, and all 6 sectors showing thinning (P ≤ 0.003). The functional changes correlated significantly with structural changes, disease duration, and severity. There was no correlation between structural changes in the retina and disease duration or severity. Subclinical visual dysfunction was observed in patients with PD with good structural-functional correlation. GCL-IPL thinning may be a more reliable parameter than RNFL thickness for structural alterations of the retina in patients with PD.
    Journal of neuro-ophthalmology: the official journal of the North American Neuro-Ophthalmology Society 03/2015; DOI:10.1097/WNO.0000000000000240 · 1.81 Impact Factor
  • Indian Journal of Ophthalmology 03/2015; 63(3):291-2. DOI:10.4103/0301-4738.156970 · 0.93 Impact Factor
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    ABSTRACT: There is an increase in the incidence of traumatic optic neuropathy (TON) due to increasing urbanization and rapid spurt in the number of motor vehicles on the road. Despite early presentation and ease of diagnosis the visual outcomes in TON are still limited. There is also significant confusion about the timing, dose and efficacy of steroid treatment in its management. To provide a clinical update of the pros and cons of steroid therapy for TON. The paper is a retrospective review of the currently available literature in the English language indexed in PubMed. A PubMed search was conducted by the authors using the following terms: Traumatic optic neuropathy, megadose, steroids, methylprednisolone. Relevant original articles, review articles, and case reports related to the topic of discussion were evaluated and discussed in the paper. There is no prospective randomized control trial evaluating the effect of steroids in TON. There are varying reports on the effect of steroid therapy from significant improvement to no difference compared to observation. The decision to give steroids to patients with TON has to be on an individual case to case basis and must involve informed consent from the patient. There are documented advantages and disadvantages of steroid therapy and a prospective, randomized, controlled trial is necessary comparing steroids, surgery and observation before definitive management can be evolved.
    Indian Journal of Ophthalmology 10/2014; 62(10):1028-30. DOI:10.4103/0301-4738.146021 · 0.93 Impact Factor
  • Indian Journal of Ophthalmology 05/2014; 62(5):662. · 0.93 Impact Factor
  • Indian Journal of Ophthalmology 05/2014; 62(5):662-662. · 0.93 Impact Factor
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    ABSTRACT: A 13-year-old child presenting with gross visual impairment was diagnosed as a case of optic atrophy. However, radiological investigations revealed osteopetrosis, which, though rare, can result in optic atrophy. The aim of this case report is to highlight this possibility while evaluating cases of optic atrophy in young patients.
    Indian Journal of Ophthalmology 04/2014; 62(4):494-5. DOI:10.4103/0301-4738.132111 · 0.93 Impact Factor
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    ABSTRACT: Purpose: The purpose of this study is to evaluate the lateral rectus periosteal fixation and partial vertical rectus transpositioning (VRT) as treatment modalities to correct exotropic Duane retraction syndrome (Exo-DRS). Materials and Methods: Prospective interventional case study of cases of Exo-DRS with limitation of adduction. A total of 13 patients were subdivided into two groups. Six patients underwent only lateral rectus periosteal fixation (group A) and seven patients also underwent partial VRT (group B). Assessment involved prism bar cover test, abduction and adduction range, extent of binocular single visual field and exophthalmometry. These tests were repeated at 1 week, 1 month and 3 months post-operatively and data analyzed. Results: The pre-operative mean values and ranges were 26.2Δ (22-35) exotropia for group A and −21.3Δ (14-30) exotropia for group B. The post-operative mean and range was +0.6Δ esotropia (+20 to −8) for group A and 8Δ (−2 to −20) exotropia for group B. Mean grade of limitation of abduction changed from −3.8 to −3.6 versus −3.6 to −2.8 and mean grade of limitation of adduction changed from −1.9 to −0.7 versus −1.5 to −0.5 in the groups A and B respectively. Mean binocular single visual field changed from 14.7° to 23.3° in group A and 11.8° to 26.4° in the group B respectively. Conclusion: Lateral rectus periosteal fixation is an effective surgery to correct the exodeviation, anomalous head posture and improving adduction in Exo-DRS and partial VRT in addition is effective in improving abduction and binocular single visual fields.
    Indian Journal of Ophthalmology 11/2013; 62(2). DOI:10.4103/0301-4738.121145 · 0.93 Impact Factor
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    ABSTRACT: Purpose: To evaluate the clinical profile and short-term visual outcome of optic neuritis (ON) patients in India. Materials and Methods: In this prospective study carried out over a period of 3 years, 99 eyes of 83 ON patients were examined and followed up for 10.8 ± 8.2 months for type of presentation, recurrence rate, and visual outcome. Results: Mean age was 27.6 ± 8.8 years. Female preponderance was seen (70% of cases). Papillitis (53.5% of eyes) was more common than retrobulbar neuritis (46.5% of eyes). Bilateral presentation was seen in 19.3% cases. Baseline median logMAR visual acuity (VA) was 1.6 ± 0.8, which improved to 0.2 ± 0.6, with approximately 64% of eyes retaining VA of 20/40 or more. Two patients had previous diagnosis of multiple sclerosis (MS). MS was newly diagnosed in two patients. Recurrence was seen in 16% of eyes and was more common in cases of retrobulbar neuritis. Conclusion: The clinical profile of ON in Indian patients is different from that in the Western population. Unlike reported in the Western literature, papillitis is frequent in the Indian setup, with lower recurrence rates but poorer outcomes.
    Indian Journal of Ophthalmology 11/2013; 62(3). DOI:10.4103/0301-4738.121131 · 0.93 Impact Factor
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    ABSTRACT: Context: Recurrence after successful treatment of amblyopia is known and understanding the risk factors could help effective management. Aim: To measure incidence of recurrence in successfully treated cases of anisometropic amblyopia and evaluate factors predicting it. Settings and Design: Cohort Study at a tertiary level institution. Materials and Methods: Successfully treated anisometropic amblyopes aged 4-12 years were followed up for 1 year after stopping therapy. Best corrected visual acuity (BCVA), refractive error, stereoacuity and contrast sensitivity were evaluated at baseline and follow-up. Statistical Analysis: Intergroup analysis with appropriate tests: Chi-square test, Fisher's exact test, Wilcoxon rank sum test and paired t-test. Results: One hundred and two patients with mean age at diagnosis 7.06 μ 1.81 years were followed-up for a mean duration of 1.0 μ 0.2 years. The mean pre-treatment BCVA (LogMAR score) at diagnosis was 0.73 μ 0.36 units which improved to 0.20 μ 0.00 with treatment and after 1 year of stopping treatment was 0.22 μ 0.07. Thirteen (12.74%) patients showed amblyopia recurrence during follow-up. Risk of recurrence was higher with older age of onset of treatment (6.64 μ 1.77 years without recurrence v/s 8.53 μ 1.39 years with recurrence, P = 0.0014). Greater extent of improvement of VA (P = 0.048) and final VA at stopping occlusion (P = 0.03) were associated with higher recurrence. Binocularity status or stereoacuity changes were not associated with risk of recurrence. Conclusions: Significant numbers of children suffer recurrence of amblyopia after stopping therapy. Older age, better BCVA after stopping therapy and greater magnitude of improvement in BCVA are important risk factors for recurrence. Careful follow-up is essential for early detection and management of recurrence.
    Indian Journal of Ophthalmology 11/2013; 61(11):630-3. DOI:10.4103/0301-4738.123144 · 0.93 Impact Factor
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    ABSTRACT: Context: Retinal nerve fiber layer (RNFL) thinning has been demonstrated in cases of optic neuritis (ON) and multiple sclerosis (MS) in Caucasian eyes, but no definite RNFL loss pattern or association with visual functions is known in Indian eyes. Aim : To evaluate RNFL thickness in cases of ON and MS, and to correlate it with visual function changes in Indian patients. Settings and Design: Cross-sectional case-control study at a tertiary level institution . Materials and Methods: Cases consisted of patients of (i) typical ON without a recent episode (n = 30:39 ON eyes and 21 fellow eyes), (ii) MS without ON (n = 15;30 eyes) while the controls were age-matched (n = 15; 30 eyes). RNFL thickness was measured using the Stratus 3 °CT. The visual functions tested included the best-corrected visual acuity (BCVA), contrast sensitivity, stereopsis, visual evoked responses, and visual fields. Statistical analysis used: Intergroup analysis was done using ANOVA and Pearson's correlation coefficient used for associations. Results: RNFL thickness was reduced significantly in the ON and MS patients compared to the controls (P-0.001). Maximum loss is in the temporal quadrant. Lower visual function scores are associated with reduced average overall RNFL thickness. In ON group, RNFL thinning is associated with severe visual field defects while contrast sensitivity has strongest correlation with RNFL in the MS group. Conclusions:RNFL thickness is reduced in ON and MS cases in a pattern similar to Caucasians and is associated with the magnitude of impairment of other visual parameters. Contrast sensitivity and stereoacuity are useful tests to identify subclinical optic nerve involvement in multiple sclerosis.
    Indian Journal of Ophthalmology 10/2013; 61(10):562-6. DOI:10.4103/0301-4738.121071 · 0.93 Impact Factor
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    ABSTRACT: Ocular dirofilariasis mostly presents as a subconjunctival or eyelid lesion. [1] Intraocular dirofilarial infestation is rare. [2],[3] We report a case of a young woman who was accidentally detected to have a live motile worm in the anterior segment in one eye and a cystic lesion on the optic disc in the other eye. To our knowledge, bilateral intraocular dirofilariasis has never been reported.
    Indian Journal of Ophthalmology 09/2013; 62(3). DOI:10.4103/0301-4738.116252 · 0.93 Impact Factor
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    ABSTRACT: To evaluate Frisby Davis distance (FD2) stereotest for determining the timing of surgical intervention in intermittent exotropia (X(T)). A prospective case-control study was conducted including 30 patients with X(T) and 30 age-matched controls. Stereoacuity was measured preoperatively and 3 months postoperatively using FD2 for distance and TNO and Randot for near. Preoperative distance stereoacuity was 43.83±35.51 arcsec (median 30 arcsec; range 10-120) which improved postoperatively to 27±33.74 arcsec (median 15 arcsec; range 5-120) (p=0.001). Cases with FD2 stereoacuity worse than 70 arcsec did not show significant improvement. Mean preoperative near stereoacuity by TNO was 94.00±79.48 arcsec (median 60 arcsec) and Randot was 50.33±39.23 arcsec (median 30 arcsec) which improved to 80.00±80.08 arcsec (median 60 arcsec) and 34.17±57.00 arcsec (median 20 arcsec), respectively, after surgery (both p=0.001). The controls had a mean distance stereoacuity of 14.66±4.13 arcsec (median 15 arcsec; range 5-20) and near stereoacuity of 63.00±21.35 arcsec (median 60 arcsec (TNO)) and 23.66±5.07 arcsec (median 20 arcsec (Randot)). There was a significant correlation between FD2 and Randot in the cases but not in controls (p=0.005), however no correlation was found between TNO and FD2. Distance stereoacuity is reduced in X(T) to a greater extent than the near stereoacuity and both improve after surgery. FD2 is useful for deciding timing of surgery and a stereoacuity worse than 20 arcsec is an indication for surgical intervention. A preoperative distance stereoacuity which is worse than 70 arcsec implies a poor prognosis for stereoacuity improvement after surgery.
    The British journal of ophthalmology 07/2013; 97(10). DOI:10.1136/bjophthalmol-2012-302321 · 2.81 Impact Factor
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    ABSTRACT: Myopia, a form of refractive error is a leading cause of visual disability throughout the world. In India uncorrected refractive errors are the most common cause of visual impairment and second major cause of avoidable blindness. Due to this the public health and economic impact of myopia is enormous. Although school vision screening programme is very successful in many states, still a significant number of school going children remain unidentified and the unmet need for correcting refractive errors in children appears to be significant.
    Indian Journal of Community Medicine 04/2013; 38(2):83-5. DOI:10.4103/0970-0218.112436
  • Oman Journal of Ophthalmology 01/2013; 6(1):61-2. DOI:10.4103/0974-620X.111925
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    ABSTRACT: A 25-year-old male presented with complaints of sudden diminution of vision with pain on eye movement in the left eye which was diagnosed clinically as retro bulbar optic neuritis. However, magnetic resonance imaging (MRI) showed lesion consistent with sphenoid sinus mucocele. Early surgical removal of mucocele led to complete recovery of vision, contrast and visual field. A high index of suspicion is necessary for intracranial lesions in all cases of retro bulbar neuritis, especially those with atypical symptoms.
    Indian Journal of Ophthalmology 05/2012; 60(3):216-8. DOI:10.4103/0301-4738.95876 · 0.93 Impact Factor
  • Journal of American Association for Pediatric Ophthalmology and Strabismus 02/2012; 16(1):e8. DOI:10.1016/j.jaapos.2011.12.030 · 1.14 Impact Factor
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    ABSTRACT: To compare cycloplegic efficacy of homatropine and atropine in pediatric refractions and derive a regression formula to calculate refraction findings for both agents. Children between the ages of 4 to 10 years with refractive error underwent cycloplegic refraction with 2% homatropine and 1% atropine by retinoscopy and automated refraction. Refractive data were compared by the use of power vector analysis. Primary outcome measures were spherical equivalent (SE), astigmatic components of refractive error (J(0) and J(45)), overall blur strength of refractive error, and residual accommodation. A total of 63 children with refractive error were enrolled (mean age, 6.7 ± 1.6 years). Compared with homatropine, atropine uncovered significantly greater hyperopic SE in patients with hypermetropia (4.2 ± 2.5 D [atropine] vs 3.5 ± 2.3 D [homatropine]; P < 0.001) as well as myopia (-1.8 ± 1.4 D [atropine] vs -2.1 ± 1.4 D [homatropine]; P < 0.001). Overall blur strength was significantly greater with atropine (3.1 ± 2.1 [atropine] vs 2.9 ± 1.9 [homatropine]; P = 0.003). Homatropine had a significantly greater residual accommodation (1.8 ± 0.4 D [atropine] vs 3.1 ± 0.5 D [homatropine]; P < 0.001). A regression formula was derived. Of the 2 cycloplegic agents, atropine yielded more consistent results than homatropine; however atropine had a relatively slow onset and prolonged effect. Our regression formula may make it possible to derive atropine-like results while using the clinically more versatile homatropine.
    Journal of AAPOS: the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus 06/2011; 15(3):245-50. DOI:10.1016/j.jaapos.2010.12.020 · 1.14 Impact Factor
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    ABSTRACT: We report a rare instance of favorable outcome in orbital apex syndrome secondary to herpes zoster ophthalmicus (HZO) in a human immunodeficiency virus (HIV)-positive patient. The patient complained of pain and decrease in vision in one eye (20/640) for 2 weeks accompanied with swelling, inability to open eye, and rashes around the periocular area and forehead. The presence of complete ophthalmoplegia, ptosis, relative afferent pupillary defect, and anterior uveitis with decreased corneal sensation prompted a diagnosis of HZO with orbital apex syndrome. The enzyme-linked immunosorbent assay test and a low CD4 count confirmed HIV. Highly active antiretroviral therapy (HAART), systemic acyclovir, and systemic steroids were started. Visual acuity and uveitis improved within 10 days. By the end of the fourth week, ocular motility also recovered and the final visual acuity was 20/25. We highlight the role of HAART, used in conjunction with systemic steroid and acyclovir therapy, in improving the outcome.
    Indian Journal of Ophthalmology 11/2010; 58(6):527-30. DOI:10.4103/0301-4738.71708 · 0.93 Impact Factor
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    ABSTRACT: To evaluate the factors affecting the restoration of stereoacuity after surgery in cases of intermittent exotropia. Thirty consecutive patients of intermittent exotropia X (T) scheduled for surgical intervention underwent preoperative evaluation, including complete ophthalmic and orthoptic examination. Deviation was measured for near and distance. Near stereo acuity was measured by The Netherland Organization stereotest (TNO), and distance stereo acuity was measured using the Frisby-Davis Distance (FD2) stereotest at 6 m for all cases and age-matched controls. All cases of X (T) were followed postoperatively at 1 week, 1 month, 3 months and 6 months. Successful surgical alignment, defined as alignment within eight prism dioptres of exophoria, was seen in 84% of cases. The median distance stereo acuity improved from preoperative value of 50 s of arc to 17.5 s of arc, and near stereoacuity improved from 240 s of arc to 90 s of arc at 6 months postoperatively. The median distance and near stereo acuity in controls were 15 and 60 s of arc respectively. There was a significant difference in both distance and near stereoacuity between controls and cases, even after surgery. A high grade of preoperative stereoacuity was found to be a significant factor in determining the achievement of normal stereoacuity postoperatively. Age and amount of pre- and postoperative deviation were not found to have any affect. None of the above-mentioned factors had any influence on successful postoperative surgical correction. There is a significant improvement in both near and distant stereoacuity postoperatively in X (T); however, the achievement of normal level depends upon the preoperative sensory status of the patient.
    The British journal of ophthalmology 10/2010; 95(8):1098-101. DOI:10.1136/bjo.2010.182139 · 2.81 Impact Factor
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    ABSTRACT: To evaluate the higher order aberrations and resultant bilateral wavefront patterns in paediatric patients with idiopathic amblyopia. Material and Methods:  In this cross sectional observational trial, seventeen consecutive patients of previously diagnosed idiopathic amblyopia underwent wavefront analysis on Zyoptix platform (Bausch and Lomb, Rochester, NY, USA). The mean age was 9 ± 3 years. There was no significant difference in comparison with means for the Zernike coefficients between normal and amblyopic eye. However, interrelation between Zernike coefficients, which is responsible for their interaction leading to difference in visual function, was different between amblyopic and fellow eyes. This was noticed using stepwise regression analysis. Predicting variables and R(2) (r squared) values for each Zernike polynomial were calculated. The sets of significantly predicting coefficients were different in most patients, with only seven common pairs and 42 dissimilar dependent-predictor sets. Maximum difference in the R-squared values between amblyopic and normal (fellow) eyes was seen with coma-like and trefoil-like aberrations (third order and fifth order terms). It seems a strong possibility that a subset of 'idiopathic' amblyopia may be associated with loss of symmetry in wavefront patterns of the two eyes.
    Acta ophthalmologica 03/2010; 89(3):e257-62. DOI:10.1111/j.1755-3768.2009.01804.x · 2.51 Impact Factor