Globally, CYP1B1 mutations in primary congenital glaucoma are strongly structured by geographic and haplotype backgrounds

Purpose: To obtain a global perspective on the distribution and evolution of CYP1B1 mutations in primary congenital glaucoma (PCG) worldwide. Methods. Five intragenic single-nucleotide polymorphisms in CYP1B1-R48G, A119S, V432L, D449D, and N453S-were used to generate haplotype data from 138 Indian patients with PCG and 132 ethnically matched normal controls, which were then analyzed in conjunction with data from other populations. Maximum-likelihood estimates of haplotype frequencies were estimated from the genotype data. Subsets of patients and normal control subjects were also genotyped with respect to eight short tandem repeat (STR) markers around the CYP1B1 locus (D2S305, D2S165, D2S367, D2S2259, D2S391, D2S3337, D2S23678, and D2S286), to gain evolutionary insights. Results: Common mutations in CYP1B1 that are causal of PCG occurred on a uniform haplotype background among Indian patients, which is completely distinct from the modal haplotype background found among unaffected control subjects. Comparison of these data with data from other global regions reveals strong clustering of CYP1B1 mutations by geographic and haplotype backgrounds. The two distinct modal haplotypes found among Indian patients with PCG and control subjects are both ancient with ages of similar magnitudes, as indicated by large variances in the number of repeats at eight STR loci. Together with data from chimpanzee and normal control subjects from India and other global regions, it was possible to make a parsimonious reconstruction of the evolution of these haplotypes. Conclusions: The strong association of specific haplotypes with some predominant CYP1B1 mutations underlying PCG and the observed geographical clustering, probably due to founder effects, may be useful for predictive testing

Likelihood ratios: Clinical application in day-to-day practice

In this article we provide an introduction to the use of likelihood ratios in clinical ophthalmology. Likelihood ratios permit the best use of clinical test results to establish diagnoses for the individual patient. Examples and step-by-step calculations demonstrate the estimation of pretest probability, pretest odds, and calculation of posttest odds and posttest probability using likelihood ratios. The benefits and limitations of this approach are discussed

Aniridia associated with congenital aphakia and secondary glaucoma

We report a case of aniridia associated with congenital aphakia and secondary glaucoma. A 35-year-old male presented with aniridia, congenital aphakia and secondary glaucoma in both eyes. After an unsuccessful medical management, he underwent trabeculectomy with mitomycin C and anterior vitrectomy under local anesthesia in his left eye. Postoperatively, at the end of six months, intraocular pressure (IOP) in his left eye was controlled without medications. This case highlights the rare association of aniridia with congenital aphakia and secondary glaucoma

How to assess a patient for glaucoma

IntroductionGlaucoma affects approximately 65 million people around the world and an expected 7.5 million are blind due to the disease. It is the second most common cause of blindness worldwide.1 It is estimated that perhaps half the blindness from glaucoma in the world is caused by angle closure.2 Accordingly, in order to be effective, any case detection has to include methods to detect angle closure.A clinic examination is different from a screening programme in the community. In the clinic the patient has sought us out and the responsibility is ours to detect and treat any pathology, including glaucoma. Some short cuts that may be satisfactory in screening programmes are not acceptable in a clinic. The best method to detect (and assess) glaucoma is to perform a comprehensive eye examination for all patients who attend the clinic, irrespective of the complaints they present with

Likelihood ratios: Clinical application in day-to-day practice

In this article we provide an introduction to the use of likelihood ratios in clinical ophthalmology. Likelihood ratios permit the best use of clinical test results to establish diagnoses for the individual patient. Examples and step-by-step calculations demonstrate the estimation of pretest probability, pretest odds, and calculation of posttest odds and posttest probability using likelihood ratios. The benefits and limitations of this approach are discussed

Learning micro incision surgery without the learning curve

We describe a method of learning micro incision cataract surgery painlessly with the minimum of learning curves. A large-bore or standard anterior chamber maintainer (ACM) facilitates learning without change of machine or preferred surgical technique. Experience with the use of an ACM during phacoemulsification is desirable

Aniridia associated with congenital aphakia and secondary glaucoma

We report a case of aniridia associated with congenital aphakia and secondary glaucoma. A 35-year-old male presented with aniridia, congenital aphakia and secondary glaucoma in both eyes. After an unsuccessful medical management, he underwent trabeculectomy with mitomycin C and anterior vitrectomy under local anesthesia in his left eye. Postoperatively, at the end of six months, intraocular pressure (IOP) in his left eye was controlled without medications. This case highlights the rare association of aniridia with congenital aphakia and secondary glaucoma