Short-term changes in topometric indices after discontinuation of rigid gas permeable lens wear in keratoconic eyes.

PURPOSE: To estimate the time taken for topometric indices to stabilize in keratoconic corneas following cessation of habitual RGP contact lens wear. METHODS: A total of 29 eyes of 20 patients, diagnosed with mild to severe keratoconus were included in this prospective observational study. All patients were experienced RGP contact lens wearers (either conventional RGP or Rose K2 lens) with each patient having used these lenses for at least a year. Corneal topography was performed immediately following discontinuation of habitual contact lens wear at baseline and each of four consecutive visits, 1-week apart. RESULTS: An overall reduction in the keratometry and thickness values were noted on tomography immediately following cessation of contact lens wear and these indices increased significantly in the 1st week (P < 0.001). Consecutive visits following the first visit did not show any significant change in the topometric parameters (P > 0.05). Subgroup analysis revealed a similar trend in eyes with "severe" keratoconus and in eyes fitted with the "three-point touch" philosophy. However, eyes with "mild-moderate" keratoconus and those fitted with "apical clearance" fitting philosophy showed marginal differences even within the 1-week period of lens cessation. CONCLUSION: Maximum changes in keratometry and pachymetry values following discontinuation of RGP lens wear stabilize within the 1st week of cessation of rigid lens wear in a keratoconic cornea. These changes were more pronounced in patients with severe keratoconus and those with an apical bearing fit. This information would be useful for practitioners to assess the progression of keratoconus in RGP lens users before collagen cross-linking.

Changing Clinical Presentation, Current Knowledge-Attitude-Practice, and Current Vision Related Quality of Life in Self-Reported Type 2 Diabetes Patients with Retinopathy in Eastern India: The LVPEI Eye and Diabetes Study.

Purpose. To document the changing clinical presentation of diabetic retinopathy (DR) over a decade, the current knowledge-attitude-practice (KAP) of known type 2 diabetes mellitus (DM) patients, and the current vision related quality of life (VR-QOL) of patients with DR in a tertiary eye care center in Eastern India. Methods. Two hundred and forty patients with known type-2 DM were evaluated. The evaluation included status of DR (n = 240), KAP (n = 232), and VR-QOL (n = 75). International classification of DR was used in the study. The DR status was compared with another cohort (n = 472) examined a decade earlier, in year 2001. The KAP-25 questions were designed after literature review. The National Eye Institute Visual Function Questionnaire (NEI-VFQ; including optional items) was validated by Rasch analysis. Both KAP and VR-QOL were analyzed according to degree of DR, duration of known DM, and educational qualification. Results. Average age of the current cohort (n = 240) was 57.16 ± 9.03 years; there were 205 (85.4%) male patients and 143 (59.6%) patients had received less than graduate qualification. The mean duration of DM since diagnosis was 10 ± 7.8 months (range 8 months to 30 years); 118 (49.16%) patients had DR. In a decade time, 2001 to 2011, there was a change of retinopathy status at presentation (more often nonproliferative diabetic retinopathy, NPDR). One-third of NPDR patients had poor vision and half of them were hypertensive. KAP was better in patients with higher education and those having DR. VFQ score was higher in better seeing patients. Conclusion. Patients currently presenting at earlier stage of retinopathy are probably related to poor vision. Early detection and treatment of DR is likely to preserve and/or improve vision.

Microbial analyses of contact lens-associated microbial keratitis.

PURPOSE: To investigate the utility of additional microbial analyses to detect the causative microorganism of microbial keratitis and to determine the strength of association between clinical variables. METHODS: This retrospective study included 125 eyes of 123 people presenting with presumed infectious keratitis associated with contact lens wear, and examined between January 2001 and November 2011. RESULTS: Sixty-three male and 60 female patients with a mean age of 24.14 ( ±6.7) and 26.7 (±10.0) years, respectively, were included in the study. Among the samples tested, 38 (40%) corneal cultures, 85 (92%) contact lens cultures, and 49 (80%) contact lens case cultures yielded positive results. In the samples for which all microbial investigations were performed and corneal culture was positive, cultures of contact lenses and corneas yielded the same microbes in 94% of cases, and for contact lens case and corneal cultures 77% of cases yielded the same microbes. Importantly, these were monocultures of the same microbe isolated from the cornea in the contact lens and lens case cultures. The odds of having a positive corneal culture was 37 times higher (p = 0.008) when patients presented to the clinic 2 weeks after the onset of symptoms. Pseudomonas aeruginosa was the predominant organism isolated, and most isolates were susceptible to commonly used antimicrobials. CONCLUSIONS: Contact lens culture might be an effective test to perform to detect and determine the causative microorganism when corneal cultures are unavailable or yield no microorganisms upon culture. A longer duration of symptoms before presenting to the clinic was significantly associated with obtaining a positive corneal culture.

RGP contact lens fitting in keratoconus using FITSCAN technology.

PURPOSE: To assess and compare the base curve (BC) of rigid gas permeable contact lens (RGP) that were calculated by FITSCAN using corneal topography (Orbscan IIz) and the diagnostic contact lens fitting method in keratoconus eyes. MATERIALS AND METHODS: A prospective comparative study of 85 keratoconus eyes was conducted. Two masked observers calculated the contact lens parameters of RGP lens by diagnostic fitting method and using FITSCAN technology. The base curves calculated by two methods were compared using Wilcoxon signed rank test and agreement between two methods were analysed using Bland-Altman plot. RESULTS: Eighty-five eyes from 55 keratoconus patients were included in the study. The mean age was 17.63±2.78 (range: 12-23) years and among them 46 were males. The keratoconus was graded into mild, moderate and severe based on average keratometry values. The base curve calculated by the FITSCAN is on average 0.22mm higher than that calculated by diagnostic method (P value <0.0001, 95% CI=0.155, 0.245, Wilcoxon signed rank test) and the bias between the two methods was found to be 2.7% (Bland-Altman plot), indicating systematic bias between the two modalities. By single linear regression analysis, the base curve of RGP contact lens could calculated by using the formula, base curve (BC)=(FITSCAN calculated BC×0.86563)+0.78738. CONCLUSION: Our study showed that selecting the BC of the initial trial lens 0.22mm steeper than the FITSCAN calculated base curve, may help to reduce the complexity of RGP contact lens fitting in keratoconus.