Evaluation of corneal biomechanical properties following penetrating keratoplasty using ocular response analyzer

Purpose: To evaluate corneal biomechanical properties in eyes that has undergone penetrating keratoplasty (PK). Materials and Methods: Retrospective observational study in a tertiary care centre. Data recorded included ocular response analyzer (ORA) values of normal and post-keratoplasty eyes [corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and cornea-compensated intraocular pressure (IOPcc)], corneal topography, and central corneal thickness (CCT). Wilcoxon signed rank test was used to analyze the difference in ORA parameter between post-PK eyes and normal eyes. Correlation between parameters was evaluated with Spearman′s rho correlation. Results: The ORA study of 100 eyes of 50 normal subjects and 54 post-keratoplasty eyes of 51 patients showed CH of 8.340 ± 1.85 and 9.923 ± 1.558, CRF of 8.846 ± 2.39 and 9.577 ± 1.631 in post-PK eyes and normal eyes, respectively. CH and CRF did not correlate with post-keratoplasty astigmatism (P = 0.311 and 0.276, respectively) while a significant correlation was observed with IOPg (P = 0.004) and IOPcc (P < 0.001). Conclusion: Biomechanical profiles were significantly decreased in post-keratoplasty eyes with significant correlation with higher IOP as compared with that in normal eyes

In-Vivo Slit Scanning Confocal Microscopy of Normal Corneas in Indian Eyes

<b>Objective: </b> To study the cellular populations of healthy corneas of Indian eyes using confocal microscopy and to evaluate the correlation with age, gender and laterality.<b> Methods:</b> The central corneas of 100 eyes of 50 healthy subjects were examined using an i<i> n-vivo</i> slit scanning confocal microscope (Confoscan 2). Images were analysed for cell densities of the epithelium, stroma and endothelium.<b> Results:</b> Good quality images enabling analysis of all cell layer populations were obtained in 74 eyes of 43 healthy subjects (22 males and 21 females) with a mean age of 31.89 &#x00B1; 13.47 (range 19-71 years). The basal epithelial cell density was 3601.38 &#x00B1; 408.19 cells/mm2 (range 3017.3 -4231.1cells/mm2). The mean keratocyte nuclei density in the anterior stroma was 1005.02 &#x00B1; 396.86 cells/mm2 (range 571.6 - 1249.6 cells/mm2) and in the posterior stroma was 654.32 &#x00B1; 147.09 cells/mm2 (range 402.6 - 1049.1 cells/mm2). Posterior keratocyte nuclei density was 30.76&#x0025; less than the anterior stromal keratocyte nuclei density. The difference in keratocyte nuclei density was statistically significant (P=0.001). The mean endothelial cell density was 2818.1 &#x00B1; 361.03 cells/mm2 (range 2118.9 - 4434 cells/mm2) and the mean endothelial cell area was found to be 385.44 &#x00B1; 42.66 mm2 (range 268.9 - 489.2 mm2). Hexagonal cells formed 22.5 - 69.4&#x0025; of the endothelial cell populations (mean 42.04 &#x00B1; 11.81&#x0025;). Mean coefficient of cell size variation was 32.29 &#x00B1; 3.06 (range 27.2 - 39.2). No statistically significant differences were found in cell densities of any corneal layer either between female and male patients or between right and left eyes. Basal epithelial cell density, anterior stromal keratocyte nuclei and posterior stromal keratocyte nuclei density were unaffected by age (r= 0.12, 0.07, - 0.12 respectively) (P= 0.001). There was a statistically significant negative correlation between mean endothelial cell density and increase in age (r= - 0.42, P=0.001). Coefficient of cell size variation and age were positively correlated (r=0.73, P=0.001). <b> Conclusion:</b> <i> In-vivo</i> slit scanning confocal microscopy is useful for the study of corneal cell populations. Our study provides normative data of these cell populations

Clinicodemographic profile and treatment outcome in patients of ocular surface squamous neoplasia

Purpose: The aim is to study the clinicodemographic profile and treatment outcome of ocular surface squamous neoplasia (OSSN). Methods: This was a retrospective observational study of 57 eyes (56 cases) with clinically diagnosed OSSN, presenting in our center over the past year. Results: The median age of presentation was 55 years with male:female ratio being 4.5:1. Systemic predisposing conditions were xeroderma pigmentosa (1) postkidney transplant immunosuppression (1), and human immunodeficiency virus infection (1). Patients with predisposing conditions had a younger median age of onset (33 years). The majority of tumors were nodular (61.4%), gelatinous (61.4%), and had limbal involvement (96%). On ultrasound biomicroscopy (UBM), mean tumor height was 2.93 ± 1.02 mm, and intraocular extension was evident in seven eyes. OSSN with intraocular extension had a mean tumor height of 4.3 ± 1.32 mm. Nodal metastasis was seen in one case at presentation. As per American Joint Committee for Cancer Classification seventh edition staging-two cases were T1, one was T2, 46 were T3 and eight were T4. Treatment advised included conservative therapy for 39; wide local excision (4 mm margin clearance) with cryotherapy for seven; enucleation in four; and exenteration in four eyes. Overall, complete regression was achieved in 88% of cases during a mean follow-up of 13.5 ± 4.6 months. Recurrence was seen in three cases, which were treated with exenteration, radical neck dissection, and palliative chemo-radiotherapy, respectively. Conclusion: Although associated with old age, earlier onset of OSSN is seen in patients with systemic predisposing conditions. Thicker tumors in the setting of a previous surgery or immunocompromised status should be considered high-risk features for intraocular extension and should be evaluated on UBM

Comparative evaluation of intraoperative aberrometry and Barrett's toric calculator in toric intraocular lens implantation

Purpose: Barrett toric calculator (BTC) is known for its accuracy in toric IOL (tIOL) calculation over standard calculators; however, there is no study in literature to compare it with real-time intraoperative aberrometry (IA). The aim was to compare the accuracy of BTC and IA in predicting refractive outcomes in tIOL implantation. Methods: This was an institution-based prospective, observational study. Patients undergoing routine phacoemulsification with tIOL implantation were enrolled. Biometry was obtained from Lenstar-LS 900 and IOL power calculated using online BTC; however, IOL was implanted as per IA (Optiwave Refractive Analysis, ORA, Alcon) recommendation. Postoperative refractive astigmatism (RA) and spherical equivalent (SE) were recorded at one month, and respective prediction errors (PEs) were calculated using predicted refractive outcomes for both methods. The primary outcome measure was a comparison between mean PE with IA and BTC, and secondary outcome measures were uncorrected distance visual acuity (UCDVA), postoperative RA, and SE at one month. SPSS Version-21 was used; P < 0.05 considered significant. Results: Thirty eyes of 29 patients were included. Mean arithmetic and mean absolute PEs for RA were comparable between BTC (−0.70 ± 0.35D; 0.70 ± 0.34D) and IA (0.77 ± 0.32D; 0.80 ± 0.39D) (P = 0.09 and 0.09, respectively). Mean arithmetic PE for residual SE was significantly lower for BTC (-0.14 ± 0.32D) than IA (0.001 ± 0.33D) (−0.14 ± 0.32D; P = 0.002); however, there was no difference between respective mean absolute PEs (0.27 ± 0.21 D; 0.27 ± 0.18; P = 0.80). At one-month, mean UCDVA, RA, and SE were 0.09 ± 0.10D, -0.57 ± 0.26D, and -0.18 ± 0.27D, respectively. Conclusion: Both IA and BTC give reliable and comparable refractive results for tIOL implantation

Ahmed glaucoma valve in post-penetrating-keratoplasty glaucoma: A critically evaluated prospective clinical study

Aim: The aim was to evaluate the outcome of Ahmed glaucoma valve (AGV) in post-penetrating-keratoplasty glaucoma (PKPG). Materials and Methods: In this prospective study, 20 eyes of 20 adult patients with post-PKPG with intraocular pressure (IOP) >21 mmHg, on two or more antiglaucoma medications, underwent AG (model FP7) implantation and were followed up for a minimum of 6 months. Absolute success was defined as 5 < IOP < 21 mmHg and qualified success as 5 < IOP < 21 mmHg with medications or minor procedures. Results: The mean IOP decreased from 42.95 ± 10.24 to 17.69 ± 3.64 mmHg (P < 0.001) and the use of medications dropped from 2.92 to 0.39 (P < 0.001) after AGV implantation. The absolute success was achieved in 11 eyes and qualified success in 9. There was no significant change in best corrected visual acuity, graft clarity, or graft thickness. Six device-related complications occurred after AGV implantations which were successfully managed with medical or minor surgical therapy. Conclusions: Postkeratoplasty refractory glaucoma managed by AGV implantation revealed a satisfactory outcome up to 6 months of follow-up

Cysticercosis of the eye

Cysticercosis is a preventable and eradicable cause of blindness endemic in the Indian subcontinent, South- East Asia and other developing countries. Ocular and orbital cysticercosis has varied presentations depending upon the site of involvement, number of lesion and the host immune response. In this article we present a review of the various clinical manifestations, diagnosis and management protocol for orbital and ocular cysticercosis. Owing to its varied presentation, cysticercosis may pose a diagnostic challenge to the health professionals. Early diagnosis and management can prevent the vision loss and optimize visual outcomes

Ocular graft versus host disease in allogenic haematopoetic stem cell transplantation in a tertiary care centre in India

Background & objectives: This study was aimed to report the occurrence of ocular graft versus host disease (oGVHD) in allogeneic haematopoietic stem cell transplantation (allo-HSCT) patients in a tertiary care hospital setting. Methods: A cross-sectional study of ocular surface of allo-HSCT patients was done. Slit lamp biomicroscopy, symptom score, tear meniscus height, fluorescein tear break-up time, Schirmer′s test I, ocular surface staining, dry eye severity, ocular surface disease index score were done. Indications for allo-HSCT, human leukocyte antigen (HLA) matching, GVHD risk factor, systemic manifestation and treatment were also noted. Results: GVHD occurred in 44.4 per cent of 54 allo-HSCT patients (mean age 26.7 ± 12 yr) included in the study. GVHD risk factors identified included female gender, relapse, older age of donor, cytomagelo virus (CMV) reactivation, and multiparous female donors. oGVHD was noted in 31.5 per cent with mean time to occurrence being 17.8 ± 21.9 months after the allo-HSCT and was observed in 89.5 per cent of chronic GVHD cases. Acute GVHD (oral and dermatological) involvement showed a significant association with GVHD in our patients (P< 0.001, 0R 23.0, CI 6.4-82.1). Chronic GVHD was observed to be associated with the occurrence of oGVHD (dry eye) (P<0.001, OR = 24.0, CI 0.02 - 0.29). Of the 34 eyes with oGHVD, dry eye of level 3 severity was seen in 16, level 2 in six, level 1 in 12 eyes. Interpretation & conclusions: GVHD occurred in 44.4 per cent of the patients studied in the present study. Acute and chronic GVHD showed a strong association with oGVHD. Dry eye disease due to chronic oGVHD was observed in 17 (31.5%) of 54 allo-HSCT patient with chronic oGVHD occurring in 17 (89.4%) of chronic GVHD cases in allo-HSCT patients. Our study on oGVHD in post allo-HSCT patients in tertiary care centre points towards the fact that ocular morbidity due to dry eye disease as a result of oGVHD is a cause for concern in these patients

Effect of phacoemulsification on measurement of retinal nerve fiber layer and optic nerve head parameters using spectral-domain-optical coherence tomography

PURPOSE: The purpose of this study is to determine the effect of phacoemulsification cataract extraction on measurement of retinal nerve fiber layer and optic nerve head parameters using spectral domain optical coherence tomography. MATERIAL AND METHODS: A prospective, hospital-based study of 100 patients of 40 years of age and above, with no other ocular morbidity except cataract and planned for phacoemulsification with IOL implantation (SN60WF) at a tertiary centre at AIIMS, New Delhi, India. All patients underwent imaging with Cirrus SD-OCT model 400 and the optic disc cube 200x200 protocol at baseline and at 1 month follow up. Paired sample t-test was used to compare the RNFL parameters and ONH parameters. RESULTS: The mean age of subjects was 56.6 ± 12.3 years (70 males, 30 females). The average RNFL increased from 92.6 ± 5.4 μm to 101.3 ± 5.6 μm after phacoemulsification, an increase of 9% (P = 0.003) and the signal strength increased from 5.6 ± 0.5 to 7.6 ± 0.7, increasing by 35.7% (P = 0.004). There was a significant increase in the disc area (P = 0.004) and rim area (P = 0.004) but no significant change in vertical cup-disc ratio (P = 0.45) or average cup-disc ratio (P = 0.075). The quadrant-wise RNFL thickness increase in inferior, superior, nasal, and temporal quadrants was 12.6% (P = 0.001), 10% (P = 0.001), 5.6% (P = 0.001), and 3.2% (P = 0.001), respectively. The change in RNFL thickness was maximum in posterior subcapsular cataract (P = 0.001) followed by cortical (P = 0.001) and nuclear (P = 0.001) subtypes. CONCLUSIONS: A significant increase in RNFL thickness and signal strength was observed after cataract surgery using SD-OCT. The maximum change in RNFL thickness was in the inferior quadrant, where RNFL thinning is a significant predictor of glaucoma progression. The posterior subcapsular cataract interfered with RNFL measurement maximally due to its density and proximity to nodal point. After the cataract surgery, a new baseline needs to be established by obtaining fresh OCT images for assessing the longitudinal follow-up of a glaucoma patient