Modern vitreoretinal surgery is now one of the most effective tools for treating posterior segment diseases. In the last several years, there has been a surge of interest in submacular surgery which allows removal of submacular choroidal neovascular membranes and haematomas. Various aspects of this rapidly emerging modality of surgery are discussed in this review.

The purpose of this study was to evaluate the immunological responses against mycobacterial antigens in Eales' disease. Fifty six patients with Eales' disease and fifty age-and-sex-matched healthy volunteers with normal fundus findings taken as controls, were subjected to Mantoux test, using 2 TU/0.1 ml of purified protein derivative (PPD), lymphocyte proliferation assay to PPD, and ELISA to detect IgM and IgG antibodies against mycobacterial A-60 antigen. The results of Mantoux test and lymphocytes proliferation assay did not differ significantly in the two groups suggesting a similar cellular immune response. The number of individuals with recent exposure/reexposure to tuberculosis (IgM+) was significantly higher among patients. However the number of people with past exposure (IgM-IgG+) was significantly higher among controls. Our study indicates that there are no statistically significant differences in the humoral and cellular immune responses to mycobacterial antigens between the patients with Eales' disease and controls, except for a significantly higher IgM positivity among the patients.

Contrast sensitivity has been recommended as a screening and diagnostic test in primary open angle glaucoma (POAG). We tested contrast sensitivity (CS) using Vistech charts in 184 eyes of 95 patients. Three groups were examined--established primary open angle glaucoma, glaucoma suspects and age matched controls. The distribution of contrast sensitivities amongst the three groups were similar. The median contrast sensitivity of glaucoma suspects and controls were well within normal limits while that of the POAG group fell along the lower limit of normal. In all three groups the younger subjects scored better than the older, indicating a depression of contrast sensitivity with increasing age. Even if depression of any one spatial frequency was considered abnormal, the test yielded a sensitivity of 55.4% and specificity of 69.5%. Similarly contrast sensitivity testing was found to be of little use in detecting field defects a maximum sensitivity of 47.3% and specificity of 73.3%. Vistech contrast sensitivity testing is not a useful test in POAG screening or diagnosis.

Fine needle aspiration biopsy (FNAB) was done in 5 patients who reported with atypical clinical presentation of intraocular tumour. The procedure was useful in 4 out of 5 cases and was without complications. With close co-operation between ophthalmologist and pathologist, FNAB is an useful adjunct for accurate diagnosis in selected patients.

In a prospective study, the efficacy of argon laser trabeculoplasty (ALT) was evaluated and compared with pilocarpine 2% as primary treatment in newly diagnosed primary open angle glaucoma (POAG). Out of 38 patients with POAG included in this study, one eye each of 36 patients underwent ALT, and one eye each of 26 patients received pilocarpine 2% every 8 hours. The mean pre-treatment IOP was 25.48±4.13 mmHg in ALT group and 24.47±3.51 mmHg in the pilocarpine group. The mean post treatment IOP at 2 year follow was 18.2±2.55 mmHg in ALT group and 18.27±2.22 mmHg in the pilocarpine group. Post treatment IOP was significantly lower than pre-treatment IOP in both ALT and pilocarpine groups. The post treatment fall in IOP showed no significant difference in ALT versus pilocarpine 2% at various follow up intervals (p>0.05). This study showed equal efficacy of ALT and pilocarpine 2% as initial therapy of POAG.

When considering the results of a study that reports one treatment to be better than another, what the practicing ophthalmologist really wants to know is the magnitude of the difference between treatment groups. If this difference is large enough, we may wish to offer the new treatment to our own patients. Even in well executed studies, differences between the groups (the sample) may be due to chance alone. The "p" value is the probability that the difference observed between the groups could have occurred purely due to chance. For many ophthalmologists assessing this difference means a simple look this "p" value to convince ourselves that a statistically significant result has indeed been obtained. Unfortunately traditional interpretation of a study based on the "p" value at an arbitrary cut-off (of 0.05 or any other value) limits our ability to fully appreciate the clinical implications of the results. In this article we use simple examples to illustrate the use of "confidence intervals" in examining precision and the applicability of study results (means, proportions and their comparisons). An attempt is made to demonstrate that the use of "confidence intervals" enables more complete evaluation of study results than with the "p" value.

This study was done to determine the prevalence of visual impairment due to refractive errors and ocular diseases in lower middle class school children of Hyderabad, India. A total of 4,029 children, which included 2,348 males and 1,681 females, in the age range of 3 to 18 years from 9 schools were screened with a detailed ocular examination protocol. Among 3,669 children in whom visual acuity could be recorded, on presentation 115 (3.1%) had visual acuity < 6/18 in the better eye (equivalent to visual impairment), while 41 (1.1%) had visual acuity of 6/60 in the better eye (equivalent to legal blindness) out of which 18 (0.5%) had visual acuity < 6/60 in the better eye (equivalent to economic blindness). Of 115 children who presented with initial visual acuity < 6/18, vision improved to ≥6/18 with refraction in 109 (94.8%). No child was legally or economically blind after refractive correction. Prevalence of hyperopia was 22.6%, myopia 8.6% and astigmatism 10.3%. The prevalence of myopia was significantly higher among children ≥10 years of age (P<0.001). The maximum, mean and median values for myopia were 10.00, 1.35 and 0.75 D in the better eye. For hyperopia these values were 8.50, 0.65 and 0.50 D. The major causes for best corrected visual acuity < 6/9 in the worse eye for 51 (1.4%) children included amblyopia in 40 (1.1%), corneal diseases in 5 (0.1%), cataract in 2 (0.05%) and others in 4 (0.1%). Out of the total, 30 (0.7%) children had strabismus. These data support the assumption that vision screening of school children in developing countries could be useful in detecting correctable causes of decreased vision, especially refractive errors, and in minimising long term permanent visual disability.