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Namrata Sharma

Publications and source records attributed to Namrata Sharma.

At least 19 recordsLinked to original sources
PubMed2026

"Tissue-specific mitochondrial dysfunction in keratoconus: An integrated structural, genomic, and functional analysis".

PURPOSE: Keratoconus (KC) is a progressive corneal ectasia characterized by stromal thinning, conical protrusion, and irregular astigmatism, leading to visual impairment. Although oxidative stress is implicated in KC, the role of mitochondrial dysfunction remains unclear. We evaluated mitochondrial structural, genomic, and functional abnormalities in corneal tissues and blood from KC patients. METHODS: This prospective study enrolled 110&#x202f;KC patients and 55 controls. Transmission electron microscopy (TEM) and immunohistochemistry (IHC) were performed on epithelial and stromal tissues from 10&#x202f;KC to 5 control corneas assessing mitochondrial morphology, oxidative phosphorylation (OXPHOS) complexes and pro-apoptotic protein NOXA. Whole mitochondrial DNA (mtDNA) sequencing and relative mtDNA copy number analysis were performed on paired blood and corneal tissues from 50&#x202f;KC patients and 35 controls including both epithelial and stromal samples. Gene expression of mitochondrial biogenesis and oxidative stress-related genes was analysed by qRT-PCR in corneal epithelium from independent 50&#x202f;KC patients and 15 controls. RESULTS: TEM revealed cristolysis, membrane disruption, and reduced mitochondrial density in KC corneas. IHC showed reduced expression of OXPHOS complexes and increased NOXA expression (p&#x202f;<&#x202f;0.05). Sequencing identified 1107 mtDNA variants, with more variants in corneal tissues than matched blood (929 vs. 576; p&#x202f;=&#x202f;0.0002). Recurrent likely pathogenic variants were enriched in complex I-encoding genes (ND4, ND5). KC corneas showed reduced mtDNA copy number, downregulated POLRMT, upregulated NOX4, and significant downregulation of multiple antioxidant genes (p&#x202f;<&#x202f;0.0001). CONCLUSION: KC patients exhibit tissue-specific mitochondrial abnormalities and impaired oxidative stress regulation, supporting a role for mitochondrial dysfunction in disease pathogenesis and highlighting potential therapeutic targets.

Corneal pathology↗
PubMed2003

Longitudinal study on visual outcome and spectacle use after intracapsular cataract extraction in northern India.

PURPOSE: More than 3 million cataract extractions are undertaken in India annually. Almost 60% of these operations are intracapsular Cataract Extractions. The subsequent optical correction is provided by aphakic spectacles. The aim of this study is to assess visual outcome and perceived benefits of post-operative use of aphakic spectacles. METHODS: One hundred and sixty-seven persons who had undergone intracapsular cataract extraction and had been given best corrected aphakic spectacles were evaluated one year following prescription of the best corrected aphakic spectacles. Out of these, 82.6% were re-examined in this interview-based longitudinal study. RESULTS: The mean age of the male participants was 65.95 years and that of females was 71.26 years. 81.2% of the participants were using the provided spectacles. There was no significant association between the spectacle use and gender of the participant. The commonest reason stated by the respondents, for the non-use of the spectacles was 'poor vision'. 61.7% of the current users of provided spectacles had a visual acuity of 6/18 or better. 91.1% of the current users were very satisfied with the spectacles. All the current users could now manage personal activities and the spectacles had facilitated independent mobility. There was no difference in the level of satisfaction between mono-aphakics and bi-aphakics. Among the satisfied users, the modal spherical power was +10 D followed by +11 D. About one-third of these required a cylindrical correction. CONCLUSION: Following intracapsular cataract extraction, provision of the best correction after cataract surgery is desirable to obtain an optimal visual outcome.

Aged↗
PubMed2003

Contact lens fitting for post-radial-keratotomy residual myopia.

PURPOSE: To formulate guidelines for contact lens fitting following radial keratotomy and to achieve a relationship between contact lens fitting parameters and refractive and keratometric parameters. METHODS: Thirty-five eyes of 30 patients who had post-radial-keratotomy residual myopia were evaluated for contact lens fitting. The base curve was selected by 'hit and trial' method until a proper fit was achieved, following which an over-refraction was done and final power of the contact lens obtained. RESULTS: The mean contact lens base curve was 43.04 +/- 1.62 D, which was steeper than the postoperative keratometry by 2.35 +/- 0.74 D. The base curve and the postoperative keratometry were correlated by regression analysis (r = 0.895, P < 0.001). The mean overall diameter of the contact lenses was 9.64 +/- 0.08 mm. The mean contact lens power was 5.81 +/- 3.07 D, which was more myopic than the residual myopia by 2.79 +/- 1.67 D. Regression analysis showed definite correlation between the contact lens power and postoperative myopia (r = 0.854, P < 0.001). CONCLUSION: For correction of post-radial-keratotomy residual myopia, contact lens fitting parameters can be determined by a regression formula using keratometric and refractive values.

Adult↗
PubMed2003

Study of corneal topographic patterns with single continuous suturing techniques in penetrating keratoplasty.

PURPOSE: To study the corneal topographic patterns following three different types of single continuous suturing techniques in penetrating keratoplasty. METHODS: One hundred forty-eight maps obtained from 40 patients who underwent penetrating keratoplasty with single continuous suturing were retrospectively analyzed at a tertiary eye care center. The videokeratograph maps were obtained on the Eye Sys System 2000 at 1, 3, and 6 months after surgery. Suture adjustment was done for cases with astigmatism greater than 3 diopters, and maps were also obtained after suture adjustment. The maps were classified according to the corneal profile and the astigmatic pattern seen in the topographic maps. RESULTS: Combined prolate patterns were seen most frequently, and their proportion was significantly higher at 1 month ( p= 0.009), 3 months ( p= 0.0004), and 6 months ( p= 0.0008). The simulated keratometric astigmatism was significantly higher in the prolate group compared with the other groups at 1 month ( p= 0.0021). However, all the topographic patterns showed comparable magnitude of astigmatism after suture adjustment and at 3 and 6 months. The antitorque suturing technique showed a higher proportion of prolate maps compared with the other suturing techniques. CONCLUSIONS: Prolate patterns of the cornea are the most frequently seen patterns after single continuous suturing, which is the normal physiological pattern of the cornea. The initial astigmatism is higher in the prolate pattern, which can be successfully reduced with suture adjustment.

Astigmatism↗
PubMed2003

PRK for epithelial ingrowth in buttonhole after LASIK.

PURPOSE: To evaluate the efficacy of photorefractive keratectomy (PRK) in progressive central epithelial ingrowth after buttonholes after laser in situ keratomileusis (LASIK). METHODS: Two eyes of two patients with progressive central epithelial ingrowth and fibrosis in flap buttonholes after LASIK underwent PRK 6 months following primary surgery. RESULTS: Epithelial ingrowth was treated successfully in both eyes. The uncorrected visual acuities were 20/20, and there was no evidence of recurrent epithelial ingrowth after 6 months. CONCLUSIONS: Photorefractive keratectomy is a useful modality in the treatment of central epithelial ingrowth in buttonholes following LASIK. As a single-step surgery, it offers both therapeutic and optical advantages by simultaneously clearing the corneal opacity and correcting the refractive error in selected cases.

Adult↗
PubMed2003

Technique of area measurement of epithelial defects.

PURPOSE: To compare two commonly used methods of area measurement of corneal epithelial defects, namely, estimation of the area of an equivalent rectangle and use of image analysis software, the gold standard. METHODS: Thirty-eight patients with corneal epithelial defects were evaluated. The largest linear dimension of the epithelial defect and its largest possible perpendicular within the confines of the epithelial defect were measured using a slit lamp. The area was then measured using digital photographs and image analysis software. A paired sample t test was used to compare the results. RESULTS: The two measurements of area correlated well (P = 0.84); their difference was insignificant (P = 0.063) and a linear regression relation between the two could be derived with an r2 value of 0.71, which was significant. CONCLUSIONS: Accurate slit-lamp measurements with estimation of the area of an equivalent rectangle can safely be used as a measure of the epithelial defect size when sophisticated image analysis software is not available.

Adult↗
PubMed2002

Posterior corneal topographic changes after retreatment LASIK.

PURPOSE: To evaluate posterior corneal topographic changes after retreatment after myopic laser in situ keratomileusis (repeat LASIK). DESIGN: Retrospective nonrandomized comparative self-controlled trial. PARTICIPANTS: Thirty-three eyes of 23 patients who underwent repeat LASIK for residual myopia. INTERVENTION: Retreatments were performed. Slit-scanning corneal topography was performed before and at 1, 3, and 6 months after repeat LASIK. MAIN OUTCOME MEASURES: Posterior corneal topographic changes before and after repeat LASIK were correlated with central corneal pachymetry (preoperatively, before repeat LASIK, after repeat LASIK), residual bed thickness (RBT) and ablation depth (after primary laser in situ keratomileusis (LASIK) and repeat LASIK). On the basis of the amount of posterior corneal elevation after repeat LASIK, the eyes were divided into two groups: group 1 (>66 micro m) and group 2 (< or =66 micro m). Student's t test/Mann-Whitney rank-sum test was used to determine the significant difference of mean level of each variable between the two groups. RESULTS: After primary LASIK, an increase in posterior corneal elevation had significant positive correlation with attempted correction (P = 0.02), ablation depth (P = 0.008), and significant negative correlation with preoperative central pachymetry (P = 0.0003), RBT (P = 0.0003), and postoperative central pachymetry (P = 0.00008). After repeat LASIK, the mean increase in posterior corneal elevation had significant negative correlation with preoperative central pachymetry (P = 0.03). However, its correlation with the ablation depth (P = 0.43) during repeat LASIK and RBT after repeat LASIK (P = 0.11) was statistically insignificant. On multiple linear regression analysis, the attempted correction (P < 0.01) and RBT after primary LASIK (P < 0.001) were two independent significant determinants of an increase in posterior corneal elevation after primary LASIK. However, for increase in posterior corneal elevation after repeat LASIK, preoperative central pachymetry (P < 0.01) and posterior corneal elevation increase after primary LASIK (P < 0.05) were the two significant determinants. Compared with group 2, group 1 had significantly high values of posterior corneal elevation both after primary LASIK (P = 0.0037) and after repeat LASIK (P = 0.0000). This group also had significantly low values of central pachymetry preoperatively (P = 0.0003) and after primary LASIK (P = 0.0001) and repeat LASIK (P = 0.0001) surgeries. The mean RBT after primary LASIK (P = 0.0006) and after repeat LASIK (P = 0.001) was also lower in group 1. CONCLUSIONS: Posterior corneal elevation increases after repeat LASIK. Eyes with an increase in posterior corneal elevation after primary LASIK and with thinner cornea are more predisposed.

Adolescent↗