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Purpose: Human intraretinal myelination of ganglion cell axons occurs in about 1% of the population. We examined myelin thickness and axon diameter in human retinal specimens containing myelinated retinal ganglion cell axons. Materials and Methods: Two eyes containing myelinated patches were prepared for electron microscopy. Two areas were examined in one retina and five in the second retina. Measurements were compared to normal retinal and optic nerve samples and the rabbit retina, which normally contains myelinated axons. Measurements were made using a graphics tablet. Results: Mean axon diameter of myelinated axons at all locations were significantly larger than unmyelinated axons (P ≤ 0.01). Myelinated axons within the patches were significantly larger than axons within the optic nerve (P < 0.01). The relationship between axon diameter/fiber diameter (the G-ratio) seen in the retinal sites differed from that in the nerve. G-ratios were higher and myelin thickness was positively correlated to axon diameter (P < 0.01) in the retina but negatively correlated to axon diameter in the nerve (P < 0.001). Conclusion: Intraretinally myelinated axons are larger than non-myelinated axons from the same population and suggests that glial cells can induce diameter changes in retinal axons that are not normally myelinated. This effect is more dramatic on intraretinal axons compared with the normal transition zone as axons enter the optic nerve and these changes are abnormal. Whether intraretinal myelin alters axonal conduction velocity or blocks axonal conduction remains to be clarified and these issues may have different clinical outcomes.

Aim: To investigate the longitudinal change in central corneal thickness (CCT) over 3 years in patients with glaucoma. Materials and Methods: The Chennai Glaucoma Follow-up Study, an offshoot of the Chennai Glaucoma Study, was designed to evaluate the progression of glaucoma. A cohort of participants in the Chennai Glaucoma Study that were suffering from glaucoma or were at a higher risk for glaucoma underwent comprehensive ophthalmic evaluation at the base hospital at 6-month intervals during the years 2004 to 2007. The CCT (average of 10 readings) was measured between 11 am and 1 pm on any given day using an ultrasonic pachymeter. Patients with a history of ocular surgery, corneal disease and usage of topical carbonic anhydrase inhibitor were excluded. No patient was a contact lens wearer. Results: One hundred and ninety-six patients (84 male, 112 female) met the inclusion criteria. We analyzed data from the right eye. The mean age of the patients was 59.97 ± 9.06 years. Fifty-nine (30.1%) of the patients were diabetic. The mean change in CCT (CCT at first patient visit - CCT at last patient visit) was 3.46 ± 7.63 μm. The mean change in CCT was 0.75 μm per year (R 2 = 0.00). Age, gender, intraocular pressure at the first patient visit and diabetic status had no significant influence on the magnitude of change in CCT. Conclusion: A carefully obtained CCT reading by a trained examiner need not be repeated for at least 3 years as long as the ocular and systemic factors known to affect the measurement of CCT are constant.

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.

In this retrospective case series, we studied the predisposing factors, causative organisms, clinical spectrum, and outcomes of 12 cases of culture-proven infectious scleritis. Nine of 12 patients had a history of preceding trauma (surgical or accidental). Past surgical history included small-incision cataract surgery (4), pterygium surgery (1), and trabeculectomy (1). Six patients had multifocal scleral abscesses due to Pseudomonas, Klebsiella, or Nocardia. Only 2 patients retained useful vision (>6/18). A poor visual acuity at presentation usually resulted in a worse visual outcome (P = 0.005). Four eyes developed phthisis. The addition of surgical intervention did not result in a significantly better visual outcome than medical management alone (P = 0.209), but resulted in a higher globe preservation rate (P = 0.045). Therefore, we concluded that infection must be ruled out in cases of scleritis with preceding history of trauma, and aggressive surgical intervention improves the anatomical outcome but does not change the visual outcome.

Aims : The aim of this study was to compare the visual field test results in healthy children obtained via the Humphrey matrix 24-2 threshold program and standard automated perimetry (SAP) using the Swedish interactive threshold algorithm (SITA)-Standard 24-2 test. Materials and Methods: This prospective study included 55 healthy children without ocular or systemic disorders who underwent both SAP and frequency doubling technology (FDT) perimetry visual field testing. Visual field test reliability indices, test duration, global indices (mean deviation [MD], and pattern standard deviation [PSD]) were compared between the 2 tests using the Wilcoxon signed-rank test and paired t-test. The performance of the Humphrey field analyzer (HFA) 24-2 SITA-standard and frequency-doubling technology Matrix 24-2 tests between genders were compared with Mann-Whitney U-test. Results: Fifty-five healthy children with a mean age of 12.2 ± 1.9 years (range from 8 years to 16 years) were included in this prospective study. The test durations of SAP and FDT were similar (5.2 ± 0.5 and 5.1 ± 0.2 min, respectively, P = 0.651). MD and the PSD values obtained via FDT Matrix were significantly higher than those obtained via SAP (P < 0.001), and fixation losses and false negative errors were significantly less with SAP (P < 0.05). A weak positive correlation between the two tests in terms of MD (r = 0.352, P = 0.008) and PSD (r = 0.329, P = 0.014) was observed. Conclusion: Children were able to complete both the visual test algorithms successfully within 6 min. However, SAP testing appears to be associated with less depression of the visual field indices of healthy children. FDT Matrix and SAP should not be used interchangeably in the follow-up of children.

Congenital eyelid imbrication syndrome (CEIS) is an extremely rare, benign, transient, self-limiting eyelid malposition disorder. The classic triad of signs in patients with a CEIS consists of bilateral upper eyelids overriding the lower eyelids when child was in sleep, bilateral medial and lateral canthal tendon laxity and tarsal conjunctival hyperemia. We report a third case of congenital combined eyelid imbrication and floppy eyelid syndrome in healthy neonate that was resolved within a week with conservative treatment.

Amblyopia screening is often either costly or laborious. We evaluated the Canon Powershot TX1 (CPTX1) digital camera as an efficient screener for amblyogenic risk factors (ARF). We included 138 subjects: 84-amblyopes and 54-normal. With the red-eye-reduction feature off, we obtained Bruckner reflex photographs of different sized crescents which suggested anisometropia, while asymmetrical brightness indicated strabismus; symmetry implied normalcy. Eight sets of randomly arranged 138 photographs were made. After training, 8 personnel, marked each as normal or abnormal. Of the 84 amblyopes, 42 were strabismus alone (SA), 36 had anisometropia alone (AA) while six were mixed amblyopes (MA). Overall mean sensitivity for amblyopes was 0.86 (95% CI: 0.83-0.89) and specificity 0.85 (95% CI: 0.77-0.93). Sub-group analyses on SA, AA and MA returned sensitivities of 0.86, 0.89 and 0.69, while specificities were 0.85 for all three. Overall Cohen′s Kappa was 0.66 (95% CI: 0.62-0.71). The CPTX1 appears to be a feasible option to screen for ARF, although results need to be validated on appropriate age groups.

Ischemic abducens nerve palsy usually presents as isolated cranial nerve palsy in the middle aged and elderly patients with known risk factors such as diabetes mellitus, hypertension, dyslipidemia, carotid artery disease, etc., In this report, we describe four patients with isolated abducens nerve palsy who presented with an acute onset diplopia whose detailed history and examination were suggestive of an ischemic etiology. Detailed systemic and laboratory evaluation revealed hyperhomocysteinemia as the only potential risk factor. To the best of our knowledge this is the first report of association of hyperhomocysteinemia and isolated abducens nerve palsy.

We investigated a case of unilateral optic nerve hypoplasia using spectral domain optical coherence tomography (SDOCT). Optical coherence tomography was done on both eyes using 5-line Raster scan for the fovea to analyze the retinal nerve fiber layer thickness, inner retinal layer thickness, outer retinal layer thickness, and optic disc cube scan for the disc. Retinal nerve fiber layer thickness, inner retinal layer thickness, and outer retinal layer thickness were manually measured at 21-points of each five lines, and results were compared between both eyes. Retinal nerve fiber layer thickness and inner retinal layer thickness of optic nerve hypoplasia were significantly thinner than the opposite eye, but there was no significant difference in the thickness of the outer retinal layer between both eyes.

Rhinosporidium seeberi , till recently known as a fungus, has been reclassified as a protistan parasite. It infects humans and many animal species. The authors describe a rare case of oculosporidiosis with involvement of the lacrimal sac exhibiting features of idiopathic orbital inflammatory disease in a young male patient. Clinical features, pathophysiology, and management of lacrimal sac rhinosporidiosis have been discussed.

We are presenting the initial results of inverted internal limiting membrane (ILM) flap technique for large macular hole. Five eyes of five patients with large diameter macular hole (>700 μm) were selected. All patients underwent inverted ILM flap technique for macular hole. Anatomical closure and functional success were achieved in all patients. There was no loss of best-corrected visual acuity in any of the patients. Inverted ILM flap technique in macular hole surgery seems to have a better hole closure rates, especially in large diameter macular holes. Larger case series is required to assess the efficacy and safety of this technique.

Systemic imaging of patients with suspect ocular tuberculosis include chest X-rays and computed tomography (CT) scans. Reports have suggested a role for 18 fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT) scans. We report on the clinical utility of 18 FDG PET/CT in two patients. Case 1: A 38-year-old female patient presented with recurrent anterior uveitis. A 18 FDG-PET scan revealed metabolically active supraclavicular and chest lymph nodes. An aspiration cytology of the cervical lymph node revealed caseating granulomas suggestive of tuberculosis. Case 2: A 58-year-old female patient presented with recurrent anterior uveitis. A 18 FDG-PET scan revealed metabolically active lymph nodes in the neck. A biopsy of the cervical lymph node revealed epithelioid granulomas suggestive of tuberculosis. Both patients were started on standard antitubercular therapy with a subsequent marked reduction of activity. PET/CT scans may suggest the sites of safe high-yield biopsies.

Pigmented paravenous chorioretinal atrophy (PPCRA) is an uncommon retinal disorder of unknown etiology that is neither well understood nor classified. We report an atypical case of PPCRA, associated with Coat′s like response (CLR) in a 64-year-old man of Asian origin. Both the eyes were involved, though asymmetrically.

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. [ABSTRACT FROM AUTHOR]

To evaluate the outcome of 20G silicone rod as monocanalicular stent in canalicular lacerations. Retrospective case series involving patients between July 2006 and June 2010. Fourteen canalicular repairs in 12 consecutive patients were done in the study period. Eleven were male and mean age was 30.5 years. A single canaliculus was involved in 10 patients and associated injury to the globe was noted in 3 patients. The median lag time between injury and repair was 3 (range 1-9) days. The mean duration of stenting was 6.9 (SD 3.2) weeks. Spontaneous extrusion of monocanalicular stent occurred in 3 patients. Patency on syringing was noted in 10 (70%) canaliculi over a median follow up of 7 (range 2-17) months. 20G silicone rod may be used as an effective and economical alternative in canalicular lacration repairs.

Unilateral extensive myelination of the peripapillary nerve fibers may be associated with anisometropic myopia, strabismus, and reduced vision. Myelination of optic nerve fibers terminate at lamina cribrosa. Yet in some patients, myelination progresses into the peripapillary retinal nerve fibers and may affect the visual acuity. In this report, we described 4 patients. All patients presented extensive peripapillary myelinated nerve fibers associated with myopic anisometropia. After routine ophthalmic and orthoptic examinations, all patients underwent treatment for amblyopia through correction with spectacles, contact lenses, and the occlusion of the good eye. Corrected visual acuity improved in 1 patient, but 3 patients had no increase in visual acuity despite treatment with full cycloplegic refraction and appropriate patching. Probably because of structural abnormalies of the macula, visual results are often disappointing with appropriate correction of the refractive error and occlusion.