Emulsification of Densiron-68 used in inferior retinal detachment surgery.

PURPOSE: To report the clinical features of eight patients presenting with emulsification of the heavier than water vitreous substitute, Densiron-68. METHODS: Two patients underwent primary inferior retinal detachment (RD) surgery, two patients underwent giant retinal tear repair, three patients had repair of inferior RD complicated by proliferative vitreoretinopathy and one patient had inferior RD surgery following repair of a scleral rupture. All patients had insertion of Densiron-68. RESULTS: Significant emulsification of Densiron-68 was seen within 12 weeks of surgery in eight cases out of a total of 40 patients receiving Densiron-68. CONCLUSION: Despite adequate Densiron fills, emulsification necessitated its removal. Emulsified Densiron may have contributed to significant intraocular inflammation, epiretinal membrane formation and cystoid macular oedema. Without removal, prolonged presence of emulsified Densiron may lead to keratopathy, secondary glaucoma and retinal toxicity secondary to partitioning of perfluorohexyloctane. This has potentially significant implications on the indications for Densiron-68 use and warrants consideration before deciding on the optimal surgical intervention for inferior RDs.

Performance of the 24-2-5 frequency doubling technology screening test: a prospective case study.

AIM: To evaluate the performance of the frequency doubling technology (FDT) 24-2-5 screening test by comparison with the established N-30-5 FDT screening test for detection of glaucoma. METHOD: A prospective random sample of individuals referred for possible glaucoma were tested with FDT screening tests 24-2-5 and N-30-5 using the Humphrey Matrix perimeter in addition to standard clinical examination relevant to glaucoma detection. Discriminatory power, reliability and test time of these tests were assessed and compared. The case definition for glaucoma was made by patient according to the established clinical diagnosis. RESULTS: Of 63 referred eligible individuals, 53 (84%) were recruited. Sensitivity and specificity for the N-30-5 screening test was 78 and 85% respectively, compared with 83% and 75% for the 24-2-5 with areas under a receiver operator characteristic curve being 0.87 and 0.92. Differences between these indices were not statistically significant. For a specificity of 95%, sensitivity values were 76% and 56% for the 24-2-5 and N-30-5 respectively. Mean (standard deviation) test duration for the FDT 24-2-5 and N-30-5 screening tests were 111 (13) and 39 (10) seconds respectively (p<0.001). A total of 19 subjects (36%) produced unreliable test results in one or both eyes when tested with the 24-2-5 screening test compared with 5 subjects (9%) with the N-30-5 (p<0.0005). CONCLUSION: Minimal discriminatory power differences existed between the two screening tests evaluated, with both screening tests exhibiting high discriminatory power for detection of individuals with glaucoma. More individuals produced unreliable results on the 24-2-5 screening, which also took longer to perform.

Long term results of primary posterior chamber intraocular lens implantation for congenital cataract in the first year of life.

AIM: To document the long term outcome of congenital cataract surgery with primary posterior chamber (PC) lens implantation in the first year of life. METHOD: A retrospective review of congenital cataract surgery in the first year of life with PC lens implantation in 18 infants, eight with unilateral and 10 with bilateral cataract. The average age at surgery was 15 weeks (range 3-44 weeks). The mean follow up was 95 months (range 60-139 months). RESULTS: The best outcomes were in the bilateral group where 50% of eyes achieved 6/18 or better, with a best acuity of 6/9. Acuities were poor in the unilateral group where only 38% achieved 6/60 or better, with a best acuity of 6/24. There was a mean refractive shift between first refraction after surgery and refraction at 36 months after surgery of -3.44 dioptres with a very wide range (+2.00 to -15.50). There was a significantly greater myopic shift in the unilateral cases. Many eyes in both groups continued to show an increasing myopic shift between 36 months after surgery and their final recorded refraction. The main complications were amblyopia, especially in unilateral cataracts, and posterior capsular opacification. Amblyopia was most probably related to a combination of early onset of dense cataract in this young age group, late presentation for initial surgery, delay in capsulotomies, and imperfect compliance with a rigorous occlusion regime. CONCLUSION: Intraocular lens implantation in infants less than 1 year of age is generally a safe procedure. The spread of final refractive error was very wide. Final refraction in the unilateral group was significantly more myopic than the bilateral group. Final acuities were often disappointing especially in the unilateral group.

Reliability and validity of the partial coherence interferometry for measurement of ocular axial length in children.

PURPOSE: To assess the validity and repeatability of partial coherence interferometry (IOLMaster) and A-scan ultrasound measurement of axial length (AL) in children. METHODS: A prospective comparison of AL measurement made by the IOLMaster optical instrument (Carl Zeiss) and ultrasound A-scan (Alcon) was performed. A total of 20 children (11 male, nine female) were recruited into the study; the mean age of the sample was 11.4 years (range 6.2-15.8). Inclusion criteria comprised individuals <16 years, with no ocular pathology and no previous eye operations or allergy to topical anaesthetics. All measurements were performed by a single examiner. RESULTS: Data on validity show that, on average, a small measurement difference existed between these groups with the IOLMaster being 0.017 mm greater than A-scan ultrasonography. The 95% confidence interval for this difference encompasses zero, demonstrating that no significant systematic bias exists between the two-measurement techniques. Overall, IOLMaster reliability exceeded that of A-scan. This is evidenced primarily by the spread of the paired test-retest difference for A-scan compared to IOLMaster. The mean test-retest difference for A-scan was considerably larger than IOLMaster at 0.042 and 0.004 mm, respectively. CONCLUSION: The results show that IOLMaster was more accurate and reproducible than the contact ultrasonographic technique when used in children. Such results indicate that IOLMaster may be a useful tool in studies of eye growth and refractive development in children.

Clinical evaluation of frequency doubling technology perimetry using the Humphrey Matrix 24-2 threshold strategy.

AIMS: To evaluate performance of frequency doubling technology (FDT) perimetry using the Humphrey Matrix 24-2 thresholding program in a hospital eye service (HES) glaucoma clinic. METHODS: A random sample of individuals referred consecutively to the HES for suspected glaucoma were examined with 24-2 threshold FDT in addition to routine clinical tests. The discriminatory power of FDT and standard automated perimetry (SAP) were assessed using glaucomatous optic nerve head appearance as the reference gold standard. RESULTS: 48 of 62 eligible referred individuals were recruited. Glaucoma prevalence was 31%. Median test duration per eye was 5 minutes 16 seconds for FDT and 5 minutes 9 seconds for SAP. There was no significant difference (p = 0.184) between proportions of individuals with reliable test results (FDT 75%, SAP 63%). Using a clinically appropriate binary criterion for abnormal visual field, sensitivity and specificity levels were 100% and 26% respectively for FDT and 80% and 52% for SAP. Both tests had higher negative than positive predictive values with marginal differences between tests. Criterion free receiver operator characteristic analysis revealed minimal discriminatory power differences. CONCLUSIONS: In a HES glaucoma clinic in which new referrals are evaluated, threshold 24-2 FDT testing with the Humphrey Matrix has performance characteristics similar to SAP. These findings suggest threshold testing using the FDT Matrix and SAP is comparable when the 24-2 test pattern is used.