Corneal and corneal epithelial thickness distribution characteristics in healthy North Indian eyes using spectral domain optical coherence tomography

Purpose: To determine the pattern of corneal thickness and epithelial thickness distribution in healthy North Indian eyes by using spectral domain optical coherence tomography (SD?OCT). Methods: The observational study measured total corneal and epithelial thickness in the central 2 mm zone and eight sectors each in paracentral 2�mm (ring 1) and midperipheral 5�mm (ring 2) zones on SD?OCT. Results: The study included 67 eyes of 67 subjects with a male:female ratio of 32:35 and mean age of 25.04 � 4.54 years. The mean central corneal and epithelial thicknesses were 505.97 � 30.12 ?m and 60.48 � 8.37 ?m, respectively. The epithelium of inferior and infero?nasal sectors in ring 1 and inferior sector in ring 2 was significantly thicker than the radially opposite sectors of the respective rings (P = 0.001; P = 0.01 and P = 0.02, respectively). Sector?wise analysis did not reveal any significant correlation between the total corneal thickness and epithelial thickness (all P > 0.05) except in the outer superior sector where there was a weak positive correlation (r = 0.28, P = 0.02). Central epithelial thickness in males (60.59 � 9.28 ?m) and females (60.37 � 7.58 ?m) was comparable (P = 0.91). Pachymetry was thinnest in the inferior, inferonasal, and inferotemporal sectors in 44.79% of eyes (n = 30), while thinnest epithelium was seen in the superior, superonasal, and superotemporal quadrants in 50.75% of eyes (n = 34). Conclusion: The epithelial thickness distribution in this sample of topographically normal healthy North Indian eyes was nonuniform and independent of the underlying corneal thickness. Epithelium was thinner in the superior cornea, whereas total corneal thickness was minimum in the inferior part

Morphological and ultrastructural characteristics of extracellular matrix changes in oral squamous cell carcinoma.

Background: The biology of oral squamous cell carcinoma (OSCC), including its progression from dysplasia to carcinoma, "field effects", genetic changes in tumor associated mucosa (TAM) and effect of matrix metalloproteinases in breaking down of matrix proteins to facilitate invasion, has been well documented. However, what remains to be done is to extrapolate this knowledge to improve patient care. Aim: The aim of this study was to observe the extracellular matrix (ECM) changes with the routine histochemical stains available to most histopathologists. Materials and Methods: The study includes 72 cases of OSCC in which the tumor and adjacent normal appearing areas were sampled to study the ECM changes with hematoxylin and eosin (H and E) and Verhoeff's-Van Gieson elastic stain (VVG). Results: Basophilic fragmentation of collagen (H and E) and clumped short elastic fibers (VVG) were seen in 12 (16.7%) cases. Of the remaining cases, 18 (25%) had a dense lymphocytic infiltrate and had no demonstrable elastic fibers. Those cases with H and E changes were further studied and compared with normal mucosa for ultrastructural changes. The ultrastructural study demonstrated an increase in oxytalan, elaunin and elastic fibers and decrease in collagen fibers with some transformation changes associated with OSCCs and lymph node metastasis. Conclusion: Changes in transformation of collagen to elastic fibers and also the loss of both the fibers in areas of lymphocytic infiltration possibly indicate degradation of ECM fibers by factors released from the lymphocytes or tumor cells and the limiting effect on the tumor by ECM remodeling.

Rose-K contact lens for keratoconus.

AIM: To report clinical experience and the comparative value of axial and instantaneous topography data in fitting Rose-K design contact lenses in moderate and severe keratoconus. MATERIALS AND METHODS: Thirty-eight eyes (of 23 patients) with keratoconus were fitted with Rose-K design contact lenses and followed up for at least six months or more. Visual acuity with habitual vision correction available was measured. Axial and instantaneous topography maps for each eye were recorded. Contact lens wear comfort was graded on a ten point rating scale every three months. RESULTS: Fourteen (100%) moderate keratoconus eyes (average Sim K 48.61 +/- 1.24D) and 23 of 24 (96%) of severe keratoconus eyes (average Sim K 60.88 +/- 5.31D) were successfully fitted with the Rose-K lenses. Final fit contact lenses in severe keratoconus had statistically significant steeper base curves compared to average axial corneal curvature than in moderate keratoconus eyes. Average simulated corneal curvature on axial maps predicted final fit contact lens base curves significantly better than on instantaneous maps. Thirty-three of the 37 eyes fitted with contact lenses maintained wear comfort over average follow up period of 13 +/- 3.5 months. CONCLUSIONS: Rose-K design rigid contact lenses are successful in visually rehabilitating 100% of moderate and 96% of severe keratoconus eyes. Most patients (90%) maintained contact lens wear comfort. Corneal curvature on axial maps is a better predictive of base curve of final fit contact lens.

Evaluation of impression smear in the diagnosis of fungal keratitis.

PURPOSE: To evaluate and compare impression smear with the conventional mechanical corneal scraping by potassium hydroxide (KOH) method in the diagnosis of fungal keratitis. MATERIALS AND METHODS: Fifty consecutive cases of clinically suspected fungal keratitis were included. Under topical anesthesia, impression smear was obtained from the lesion, followed by the conventional mechanical scraping and both were transferred to sterile glass slides. The slides were examined under direct microscopy with KOH 10% wet mount. Impression smear KOH was compared with the scraping KOH and culture. RESULTS: The KOH smear was positive in 36 (72%) patients with impression smear technique and positive in 35 (70%) patients from corneal scrapings. Sensitivity of impression smear technique as compared to scraping was 97.14%, specificity 92.86%, positive predictive value 94.4%, negative predictive value 92.86%, false positive rate 5.56%, false negative rate 7.14% and accuracy was 94%. As compared to culture, the sensitivity was 100%, specificity 46.67%, positive predictive value 55.56%, negative predictive value 100%, false positive rate 53.33%, false negative rate 0% and accuracy was 68%. CONCLUSION: Impression smear KOH examination is comparable to conventional mechanical corneal scraping KOH examination in making a tentative diagnosis of fungal keratitis and can be accurately relied upon for initiating anti-fungal therapy.

ProTon tonometer determination of intraocular pressure in patients with scarred corneas.

PURPOSE: To evaluate the measure of intraocular pressure (IOP) in patients with scarred corneas obtained from the affected and non-affected areas. MATERIALS AND METHODS: Eighteen patients with small maculo-leucomatous corneal opacity following microbial keratitis were prospectively included in the study. Goldmann applanation tonometry was done first on the non-affected corneal surface. ProTon tonometry (PT) was then carried out on the same eye, to obtain IOP measurements from the non-affected (PT1) and the affected area (PT2) of the cornea. The IOP measurements were compared using a two-tail paired t test. RESULTS: The mean of IOP measurements of PT 2 and PT1 was 22 mm of Hg (SD +/- 5.2) and 14.8 mm of Hg (SD +/- 5.4), respectively. The higher reading of PT2 was statistically significant ( P < 0.001). The mean Goldmann applanation tonometry was 14.6 mm of Hg (SD 5.4) and it did not differ significantly ( P = 0.86) from the PT1 readings of 14.8 mm of Hg (SD 5.4). CONCLUSION: In patients with maculo-leucomatous corneal opacity, determination of IOP by ProTon tonometer varies from the affected to the non-affected area. The ProTon tonometer overestimates the level of IOP when it is applied to a leucomatous corneal opacity.

Low dose mitomycin-C in severe vernal keratoconjunctivitis: a randomized prospective double blind study.

PURPOSE: To study the efficacy and safety of low dose topical Mitomycin C (MMC) in severe Vernal keratoconjunctivitis (VKC). DESIGN: Placebo controlled double masked randomized clinical trial. MATERIALS AND METHODS: Twenty-eight patients with severe VKC were randomly assigned to receive either topical MMC (0.01%) (n=17) or distilled water (n=11) three times daily for a period of two weeks. Signs and symptoms were recorded on day of presentation and at the end of treatment period (2 weeks). Mann Whitney test was used to analyze the signs and symptoms in the two groups. RESULTS: No statistically significant difference was observed in terms of severity of symptoms at presentation. At two weeks patients in the MMC group showed significant decrease in tearing, foreign body sensation, discharge, hyperemia, punctate keratitis, limbal edema and trantas spots. No adverse effect of MMC was observed. CONCLUSION: Short term low dose topical MMC is an effective and safe drug to control acute exacerbations in patients of severe VKC refractory to conventional treatment.

Seborrheic keratosis of the conjunctiva.

Seborrheic keratosis can simulate a malignant melanoma and should form the differential diagnosis of a malignant melanoma. Histopathology is confirmatory.