Sensitivity and specificity of the step VEP in suspected functional visual acuity loss.

BACKGROUND/AIM: Early and accurate diagnosis of functional visual loss (FVL) allows optimum management. Visual evoked potentials (VEPs) offer a means of objectively estimating acuity and therefore could assist with early and accurate diagnosis. The aim of this study was to assess the sensitivity and specificity of the step VEP in diagnosing FVL. METHODS: A retrospective audit was conducted in 36 school-aged children presenting with reduced visual acuity and clinical suspicion of FVL. All had undergone step VEP testing as part of their investigation. Medical notes were reviewed, and where necessary, referring centres, general practitioners or electronic clinical portals were consulted to obtain longer-term outcome data. RESULTS: Twenty-seven of the 36 patients (75%) were classified as having had FVL: all had a normal step VEP spatial threshold. Nine patients (25 %) had an organic cause for their acuity loss, of whom seven had abnormal step VEP spatial thresholds: the other two patients had some functional overlay to their organic disease. The step VEP sensitivity was 78% (95% confidence interval 40-96%), and specificity was 100% (95% confidence interval 84-100%). CONCLUSION: The high specificity of the step VEP for FVL warrants increased suspicion of an organic cause should the step VEP spatial threshold be abnormal.

First-year experience of chemotherapy for advanced retinoblastoma in Tanzania: disease profile, outcomes, and challenges in 2008.

PURPOSE: To examine the profile of retinoblastoma in a national tertiary referral center in Tanzania and to report first-year outcomes of its treatment using chemotherapy. METHODS: All patients with retinoblastoma referred in 2008 were included. Disease was classified on clinical grounds as ocular, orbital, or metastatic. Those with ocular and orbital disease received chemotherapy. Remission was the main outcome measure and defined as absence of disease at the end of treatment. RESULTS: In 2008, 37 patients (20 males and 17 females) with retinoblastoma were referred to Ocean Road Cancer Institute. The mean delay from the first sign of disease to presentation at hospital was 10.4 ± 8.7 months. Disease was ocular in 32% (12 of 37), orbital in 57% (21 of 37), and metastatic in 11% (4 of 37). Of those with ocular disease, 67% (8 of 12) completed chemotherapy and all (8 of 8) achieved remission. In contrast, 48% (10 of 21) with orbital disease completed chemotherapy and only 50% (5 of 10) achieved remission. The difference in outcome between the groups was statistically significant (P = .001, Fisher exact test). CONCLUSION: The profile of retinoblastoma in Tanzania is skewed toward severe invasive disease. Despite the introduction of chemotherapy, further improvements in mortality and morbidity can only be achieved through emphasis on early detection.

Goldmann tonometry versus the Tono-Pen XL for intraocular pressure measurement: an evaluation of the potential impact on clinical decision making in glaucoma.

AIM: To assess the validity of the Tono-Pen XL as an alternative to the Goldmann applanation tonometer (GAT) for the measurement of intraocular pressure (IOP) in patients with ocular hypertension (OHT) and glaucoma. METHODS: Over a 3 month period, patients with OHT or glaucoma attending a general clinic had IOP measurements taken using the Tono-Pen XL and the GAT. Tono-Pen measurements were taken by suitably trained nursing staff, while Goldmann tonometry was performed by the examining ophthalmologist. RESULTS: There were 124 eyes of 62 patients in this study. Overall, mean IOP was 18.3 +/- 4.8 mmHg using GAT and 18.8 +/- 5.5 mmHg using the Tono-Pen. Using the Bland-Altman method, the upper and lower limits of agreement between the two devices were +10.6 mmHg and -9.6 mmHg, respectively. Significant over- and under-estimates of IOP were noted in 10 (16%) patients. CONCLUSION: Our findings suggest that the Tono-Pen XL cannot be used as a substitute for GAT in the management of patients with glaucoma or OHT.

A simple correction for congenital tarsal kink associated with distichiasis.

Congenital tarsal kink is a rare condition. The folded edge of the upper tarsus, or the inturned lashes, may traumatize the cornea causing ulceration. We describe a case of unilateral upper eyelid horizontal tarsal kink associated with distichiasis and congenital corneal ulceration. Several different surgical treatment options have been previously alluded to in the literature including lamellar tarsoplasty, full-thickness eyelid fracture, and rotation and excision of the kink with tarsal reapposition. Repair by means of eyelid everting sutures via an anterior lamellar approach is presented as a novel technique to correct this congenital anomaly.