Prescription of near addition and its relation to accommodative reserve in presbyopia - The dichotomy between theory and practice.

PURPOSE: To study the relationship between the amplitude of accommodation (AA) measured by the Royal Air Force (RAF) rule and near addition (NA) prescribed in presbyopic patients to assess how far practice is different from theoretical recommendations. METHODS: Patients, aged 40 to 60 years with best corrected vision of 6/6 N5 were included in this cross sectional observational study. AA was measured using the RAF rule. Refined with near Duochrome chart, the NA was given with the chart at 40 cm. Accommodative reserve was calculated from the measured AA, NA required and the calculated additional accommodation expended by the patient for reading. The percentage of reserve was calculated with and without the correction for depth-of-field. RESULTS: A total of 130 patients were studied. In the patients above 50 years of age, the negative correlation of AA with age was -0.298 (P = 0.065) and AA and NA was -0.365 (P = 0.002) was weak. Among the patients aged between 40 and 50 years, the negative correlation of AA with Age and NA were strong; -0.853 (P < 0.0001) and -0.823 (P < 0.0001) respectively. When prescribing glasses, 62.01% (CI 58.78 to 65.23) and 90.93% (CI 62.50 to 119.37) of the AA was found to be kept in reserve for patients below and above 50 years of age respectively. CONCLUSION: Accommodative reserve kept in our study patients when prescribing NA was two to three times the theoretical recommendation. High percentage of accommodation kept in reserve suggest that the measured AA is not activated normally and require higher NA and one should not rely on patient's ability to generate accommodative power especially in patients over 50 years.

Prevalence of Refractive Errors and Number Needed to Screen among Rural High School Children in Southern India: A Cross-sectional Study.

INTRODUCTION: Avoidable blindness is mainly due to uncorrected refractive errors (URE). School Eye Screening (SES) can be used as an initiative to address this issue. AIM: To determine prevalence of URE and Number Needed to Screen (NNS) to find one child with low vision or blindness from URE among rural school children. MATERIALS AND METHODS: A cross-sectional study was performed in 22 government schools with sixth to ninth grades in Kaniyambadi block of Vellore District of Tamil Nadu, India. There were 4739 children on the rolls. Among children present, all those identified to have a visual deficit in either eye, using a single line 20/40 Snellen's optotype E chart at 6 m, were referred to the hospital for confirmatory evaluation. Blindness (uncorrected) was defined as inability to see 20/200 in the better eye. In two of these schools, visual deficits were validated through a second school based examination by a clinician. RESULTS: Of the 4739 children on rolls, 601 were absent; all 4138 (87.3%) who were present underwent screening; 2.3% (98) {95% Confidence Interval (CI) 1.8 to 2.8} failed the screening test in at least one eye and were referred for examination. Only 28 (28.6%) of 98 children who were referred came for examination to the hospital. In the 2 of the 22 schools where the visual deficit was validated, there were no false positives. The prevalence of refractive error in these two schools was 2.2% (95% CI 1.7 - 2.7). NNS to detect one child with low vision or blindness from URE was 147. CONCLUSION: Magnitude of refractive error, low NNS, low response to referral necessitates complete care at school and hence a relook at the current SES program.

Diabetes and Diabetic Retinopathy: Knowledge, Attitude, Practice (KAP) among Diabetic Patients in A Tertiary Eye Care Centre.

INTRODUCTION: Diabetic retinopathy is becoming an increasingly important cause of visual impairment in India. Many diabetic patients who come to our centre have undetected, advanced diabetic retinopathy. If diabetic retinopathy had been detected earlier in these patients, irreversible visual impairment could have been prevented. AIM: To document Knowledge, Attitude and Practice (KAP) patterns of diabetic patients regarding diabetes and diabetic retinopathy, to determine association between them, and to identify barriers to compliance with follow up and treatment regimes. MATERIALS AND METHODS: This was a hospital-based, cross-sectional study, conducted at the Department of Ophthalmology at Christian Medical College, Vellore, Tamil Nadu, India, over a six-month period from June 2013 to November 2013. Two hundred and eighty eight diabetic patients, who fulfilled the eligibility criteria, were included in the study. KAP of patients was assessed using a 45-point, verbally administered questionnaire. Patients were placed in different categories, such as, 'good/ poor' knowledge, 'positive/negative' attitude and 'good/poor' practice. Data were analysed using Chi-square test and binary logistic regression, as appropriate. The proportion of patients with 'good/poor' knowledge, 'positive/negative' attitude and 'good/poor' practice, and the association between KAP were studied. Barriers to compliance with follow up/treatment regimes were identified. RESULTS: Out of the 288 patients in the study, 42% had good knowledge about diabetes, but only 4.5% had good knowledge about retinopathy. Good knowledge about diabetes was significantly associated with positive attitude towards diabetes and good practice patterns regarding retinopathy; awareness of retinopathy was also significantly associated with good practice. A total of 61.1% of patients did not have periodic eye examination; most common barrier identified was lack of awareness about the necessity for this (38.5%). CONCLUSION: Good knowledge about the disease was significantly associated with positive attitude and good practice patterns. Knowledge about diabetic retinopathy was poor among the patients in our study. Lack of awareness concerning the need for screening for retinopathy was a major barrier to regular screening. There is an urgent need to educate diabetic patients about this potentially blinding complication of diabetes.