We Fong Siah

Clinical outcomes of amniotic membrane transplantation in the management of acute ocular chemical injury

Background Amniotic membrane transplantation (AMT) has been used in the management of acute ocular chemical burns to promote epithelialisation, reduce inflammation and restore ocular surface integrity. The aim of this study is to analyse the morphological and functional outcomes of patients receiving AMT after ocular chemical burn. Methods We performed a retrospective analysis of all patients treated for acute ocular chemical burn between 1998 and 2008 in two participating centres (University of Duisburg-Essen, Germany and Royal Victoria Infirmary, Department of Ophthalmology, Newcastle University, UK). Ocular chemical burns were classified by Roper-Hall and Dua classifications. Results 72 eyes of 54 consecutive patients aged 37.3 years (±SD 11.6 years) were included in this cohort study. 7 chemical burns were acid burns, 61 were alkaline and 4 were of unknown origin. In 37 eyes (51.4%), AMT was applied within the first 6 days after injury. Mean follow-up time was 36.4 months (median 18.5; 1.3–117.3  months). Overall, 29 eyes (40.3%) achieved a best-corrected visual acuity of LogMAR 0.2 (0.63 decimal) or better at final visit. Complete 360° limbal stem cell deficiency (LSCD) occurred in 33 eyes (45.8%), while partial LSCD occurred in 21 eyes (29.2%). Conclusion AMT is an effective adjunctive treatment in the management of acute ocular chemical burns to support epithelial healing and restore ocular surface integrity with potential to improve vision. However, long-term debilitated vision remained in those with severe burns complicated by LSCD.

Lower Macular Pigment Optical Density in Foveal-Involved Glaucoma

PURPOSE To evaluate the relationship between macular pigment optical density (MPOD) and structural parameters of the macula and optic nerve head in glaucomatous eyes. DESIGN A cross-sectional analysis of the baseline data collected during the Macular Pigment and Glaucoma Trial (ISRCTN registry number: 56985060). PARTICIPANTS Eighty-eight subjects (48 male, 40 female) with a diagnosis of open-angle glaucoma and a median age of 67 years (interquartile range, 13; range, 36-84 years) were enrolled in this trial. METHODS The MPOD at 0.25°, 0.5°, and 1° retinal eccentricity was measured using a customized heterochromatic flicker photometry technique. Glaucoma-related structural parameters were captured using RTVue Fourier-domain optical coherence tomography (FD-OCT). Statistical significance was set at P < 0.01, and P values ranging from 0.01 to 0.05 were considered borderline significant. MAIN OUTCOME MEASURES The MPOD and its relationship to the macula and optic nerve head topography in glaucomatous eyes. RESULTS The MPOD peaked centrally at 0.25° of retinal eccentricity (mean ± standard deviation, 0.23±0.14) and decreased at more peripheral eccentricities. For the overall group, borderline significant correlations were observed between MPOD and a range of topographic measures, including inferior peripapillary retinal nerve fiber layer (RNFL) thickness, inferior ganglion cell complex (GCC) thickness, foveal inner retinal thickness, cup-to-disc area ratio, and optic disc rim area. Glaucomatous eyes with GCC loss involving the foveal zone on FD-OCT imaging (n = 52) had lower MPOD at 0.25°, 0.5°, and 1° of retinal eccentricity compared with those without foveal GCC involvement (P < 0.001, for all). Those with foveal GCC loss also had greater glaucoma severity, and this was evident by lower GCC and RNFL thickness, greater cup-to-disc area ratio, and lower optic disc rim area (P < 0.001 for all). CONCLUSIONS Our observations indicate that MPOD is lower in glaucomatous eyes with foveal GCC involvement relative to those without foveal involvement. A longitudinal evaluation of MPOD and structural change among patients with glaucoma is required to elucidate the nature of any causal relationship that might exist between MPOD and foveal damage in glaucoma.

Macular pigment is associated with glare-affected visual function and central visual field loss in glaucoma

Aim To evaluate the relationship between macular pigment optical density (MPOD) and glare disability in open-angle glaucoma. Methods A cross-sectional analysis of baseline data (88 subjects; median age, 67 (range 36–84) years) collected during the Macular Pigment and Glaucoma Trial (ISRCTN registry number: 56985060). MPOD at 0.25°, 0.5° and 1° of retinal eccentricity was measured using customised heterochromatic flicker photometry. Mesopic contrast sensitivity with glare (mCSg), photostress recovery time (PRT) and self-reported glare symptoms were evaluated. Fourier-domain optical coherence tomography was used to analyse ganglion cell complex (GCC) and identify foveal involvement. Results Low spatial frequency (f) mCSg was significantly correlated with MPOD at 0.25°(3 cycles per degree (cpd): r=0.25, p=0.04) and 0.5° (3 cpd: r=0.23, p=0.04) of retinal eccentricity. Those with foveal GCC loss exhibited lower MPOD, had worse low spatial fmCSg (1.5 cpd and 3 cpd, p=0.02 each) and prolonged PRT (p=0.02) in comparison with those without foveal involvement. The depth of central 10° field loss was related to MPOD at all eccentricities (p<0.01 for all). Those who reported glare symptoms had a significantly lower MPOD at all retinal eccentricities (0.25° and 1°: p=0.05 each; 0.5°: p=0.04), including those with foveal involvement (0.25°: p=0.05; 0.5°: p<0.01; 1°: p=0.01). Conclusions Macular pigment level may be an important consideration among those experiencing disability glare in glaucoma, including those with foveal involvement. Trial registration number ISRCTN56985060, Post-results.

Microbial keratitis in corneal grafts: predisposing factors and outcomes

PurposeTo identify the nature of microbial keratitis in corneal grafts and the clinical outcomes at a tertiary hospital in the United Kingdom.Patients and methodsA retrospective case series of microbial keratitis in corneal grafts at the Royal Victoria Infirmary, Newcastle upon Tyne over a 17-year period (1997–2014).ResultsA total of 759 consecutive corneal grafts were identified from the Cornea Transplantation database. Of these, 59 episodes of microbial keratitis occurred in 41 eyes of 41 patients (5.4%; 19 male, 46.3%). Median patient age was 73 years (SD=19.4 years). The most common indication for corneal transplantation was bullous keratopathy (11/41, 26.8%). There were 34/59 (57.6%) episodes of culture-positive graft keratitis; Streptococcus pneumoniae and Staphylococcus aureus were each isolated in 5/34 (14.7%) culture-positive episodes. In all, 35/59 (59.3%) episodes of microbial keratitis occurred in 22 previously failed grafts and 3 de novo graft failures. Gram-negative keratitis was more likely to cause reduced BCVA after (χ2-test, P=0.02). Median graft duration was 49.5 months (SD=43.7 months). Failed grafts were significantly older (median 69 vs 27 months, P=0.009).ConclusionThis represents the longest published follow-up data on microbial keratitis and is the only of its kind in the United Kingdom. The incidence of 5.4% is comparable to that within the developed world. Graft age was significantly associated with graft failure in microbial keratitis; the ongoing risk of microbial keratitis warrants providing patients with long-term open access to hospital eye services.

Surgical Management of Heavy Eye Phenomenon

Heavy eye phenomenon can be cosmetically unaccepted due to significant pseudoproptosis and hypotropia. We highlight the salient features of this condition, and report successful cosmetic outcome following a staged procedure comprising orbital decompression and horizontal recti surgery.