Intraocular oxygen distribution in advanced proliferative diabetic retinopathy.

PURPOSE: To determine the preretinal distribution of oxygen in advanced proliferative diabetic retinopathy, and to investigate the relationship between intraocular oxygen tensions and vitreous cytokine concentrations. DESIGN: Comparative cross-sectional study. METHODS: Oxygen levels were measured at sites in the vitreous and at the inner retinal surface using an optical oxygen sensor in 14 control subjects and in 14 subjects with advanced proliferative diabetic retinopathy who had developed tractional retinal detachments despite previous panretinal photocoagulation. The vitreous and plasma concentrations of 42 cytokines were measured using multiplex cytokine arrays and their correlation with intraocular oxygen tension was investigated. RESULTS: The mean oxygen tension in the mid-vitreous in diabetic retinopathy was 46% lower than that in control subjects (P = .017). However, the mean preretinal oxygen tension at the posterior pole in diabetic retinopathy was 37% higher than in controls (P = .039). We measured significant alterations in the vitreous concentrations of 9 cytokines-eotaxin, Flt-3 ligand, growth-related oncogene (GRO), interleukin (IL)-6, IL-8, IL-9, IFN-inducible protein-10 (IP-10), macrophage-derived cytokine (MDC), and vascular endothelial growth factor (VEGF)-in advanced proliferative diabetic retinopathy, and found that oxygen tension at the posterior pole was directly correlated with vitreous VEGF concentration. CONCLUSION: We identified significant intraocular oxygen gradients in proliferative diabetic retinopathy. Our findings are consistent with the hypothesis that VEGF induces the development of neovascular complexes in the posterior retina that are richly perfused but nonetheless fail to redress hypoxia in the mid-vitreous. Upregulation of vitreous VEGF may be a consequence of retinal hypoxia at unidentified sites or of chronic inflammatory processes in advanced proliferative diabetic retinopathy.

Orbital blowout fractures and race.

PURPOSE: To examine the type of orbital blowout fracture and its variation with race. DESIGN: Retrospective review of computed tomography (CT) scans and demography in an unselected cohort of patients with orbital blowout fractures. PARTICIPANTS: Patients with a high-resolution CT scan of adequate quality for analysis who presented with an orbital blowout fracture to the Orbital Clinic at Moorfields Eye Hospital. Patients with fractures involving the orbital rim or the cranium, or with penetrating injuries of the globe or orbit, were omitted from the study. METHODS: Demographic and ethnic information was collected for each patient, and the orbital scans were reviewed by a single observer. On the basis of coronal and axial imaging, a fracture was classified as affecting up to 4 areas: the floor lateral to the infraorbital canal (area 1, "A1"), the floor medial to the canal ("A2"), the maxillo-ethmoidal strut ("inferomedial" strut, "A3"), and the medial wall blowout fracture ("A4"); with fractures involving the inferomedial strut, it was noted whether there was displacement or rotation of the strut. Ethnic origin was classified as Caucasian, Afro-Caribbean, or Asian (Oriental or Indian). MAIN OUTCOME MEASURES: The proportion of different walls involved in orbital blowout fractures within 3 ethnic groups. RESULTS: A total of 152 patients (125 men, 82%) had imaging adequate for analysis; 103 (68%) were Caucasian, 19 (12%) were Afro-Caribbean, and 30 (20%) were Asian. Caucasians most commonly had floor fractures (A1 or A2 in 56 orbits, 54%) compared with 10 of 103 purely medial fractures (A4, 10%); in contrast, medial fractures were the most common type in Afro-Caribbean patients (7/19 cases, 37%), and purely floor fractures occurred in only 2 cases (10%) (P<0.005). Asian patients had results similar to those for Caucasian patients, with isolated floor fractures being the most common (14/30 cases, 47%). CONCLUSIONS: Most blowout fractures involve the orbital floor in Caucasian and Asians, whereas in Afro-Caribbeans the most common site for fracture is the medial wall. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Long-term outcome of primary congenital glaucoma.

PURPOSE: To evaluate the long-term outcome of primary congenital glaucoma in patients followed for more than 20 years. METHODS: All patients with a diagnosis of congenital glaucoma who were examined in the pediatric glaucoma clinic at Moorfields Eye Hospital from 2005 to 2006 were included. The follow-up period was a minimum of 20 years; patients with pediatric glaucoma secondary to other etiologies were excluded. Data collected included visual acuity, optic disk cupping, intraocular pressure (IOP), corneal diameter, pachymetry, visual fields, refraction, strabismus, glaucoma management, and ocular comorbidity. Progressive congenital glaucoma, defined as an increase of the cup/disk ratio of >0.2 secondary to elevated IOP, was evaluated with the use of Kaplan-Meier survival curves. Patients were divided into 1 of 3 groups: (1) stable glaucoma with no visual impairment; (2) glaucoma progression with sight-threatening consequences; and (3) poor visual acuity as a result of ocular comorbidity. RESULTS: A total of 30 eyes of 16 patients were identified. Mean follow-up was 34 ± 10 years (range, 22-59 years). At the final clinical assessment, mean IOP was 13.6 ± 4.3 mm Hg and mean cup/disk ratio was 0.7 ± 0.3 (p < 0.05). Survival analysis demonstrated lack of progression in 90.3% at 1 year, 83.1% at 5 years, 70.8% at 10 years, 58.3% at 34 years, and 48.6% at 40 years. CONCLUSIONS: Apparently stable congenital glaucoma may progress with sight-threatening complications after many years of IOP stability. Monitoring of these patients is indicated throughout life.

Laser iridotomy in dark irides.

BACKGROUND: Laser iridotomy is the established treatment for angle-closure glaucoma. Nd:YAG (neodymium: yttrium-aluminium-garnet) laser iridotomy is challenging in the heavily pigmented irides of African and Asian patients, AIM: To present a modified laser iridotomy technique for use in dark irides. METHODS: The argon laser was applied in two stages: firstly, low-power argon was applied, which created a circular area of pitted iris stroma in the superior iris. High-power argon was then applied in the same area to form a punched-out crater at the level of the radial muscle fibres. The iridotomy was then completed with low-energy YAG laser. RESULTS: 15 eyes of 8 consecutive patients who underwent successful combined argon-YAG laser iridotomy using low levels of YAG energy in dark irides is presented. The combined technique avoids common issues associated with the use of pure YAG laser, including high energy levels and a high risk of iris haemorrhage. CONCLUSIONS: Combined two-stage argon and YAG laser is an effective technique in the treatment of angle-closure glaucoma of dark irides of African and Asian patients. The technique is more effective and has reduced complications in comparison to pure argon or YAG laser techniques.

Optic disk size and optic disk-to-fovea distance in preterm and full-term infants.

PURPOSE: Few studies have assessed optic disk and retinal morphology in infants. Here the optic disk and optic disk-to-fovea distance were measured in preterm and full-term infants in vivo. METHODS: Optic disk (OD) dimensions and the center-to-center distance between the OD and the macula were measured using digital imaging in infants undergoing routine ophthalmic examinations. Postmenstrual age of the mother at the time of examination ranged from 32 to 50 weeks. From each image, the OD-to-fovea distance (ODF) and the OD height (ODH) and OD width (ODW) were measured. RESULTS: In 51 retinal images from 51 infants, mean +/- SD values obtained were 4.4 +/- 0.4 mm (ODF), 1.41 +/- 0.1 9 mm (ODH), and 1.05 +/- 0.13 mm (ODW). These dimensions did not change significantly over the age range studied. The mean value for the ratio between ODF and mean OD diameter (ODF/DD) was 3.76. CONCLUSIONS: Results of this in vivo study suggest that though the optic nerve head diameter increases by more than 50%, only limited growth occurs at the highly organized area of the posterior pole from birth to adulthood. This study discusses the finding of a large-angle kappa in infants and the use of a disk macula/disk diameter ratio in the diagnosis of optic nerve hypoplasia.

Evaluation of a toric intraocular lens with a Z-haptic.

PURPOSE: To evaluate the efficacy and rotational stability of the MicroSil 6116TU foldable 3-piece silicone toric intraocular lens (IOL) (HumanOptics). SETTING: Department of Ophthalmology, Hillingdon Hospital, Uxbridge, Middlesex, United Kingdom. METHODS: This prospective observational study included 21 eyes of 14 consecutive patients with more than 1.50 diopters (D) of preexisting corneal astigmatism having cataract surgery. Phacoemulsification was performed, and a MicroSil 6116TU toric IOL was inserted through a 3.4 mm temporal corneal incision. LogMAR uncorrected visual acuity (UCVA), best corrected visual acuity, refraction, keratometry, and cylinder axis of the toric IOL were measured. RESULTS: The mean preoperative refractive and keratometric astigmatism was 3.52 D +/- 1.11 (SD) and 3.08 +/- 0.76 D, respectively. Six months postoperatively, the logMAR UCVA in eyes without ocular comorbidity (n = 14) was 0.20 +/- 0.15 (Snellen 20/32). Seventy-nine percent (11 eyes) had a visual acuity of 0.24 (Snellen 20/35) or better. The mean refractive astigmatism at 6 months was 1.23 +/- 0.90 D. Vector analysis using the Holladay-Cravy-Koch method showed a mean reduction in refractive astigmatism of 2.16 +/- 2.33 D. The mean difference between intended and achieved cylinder axis at 6 months was 5.2 degrees (range 0 to 15 degrees). No IOL rotated more than 5 degrees during the follow-up period. CONCLUSIONS: The MicroSil 6116TU toric IOL reduced visually significant keratometric astigmatism and increased spectacle independence. The IOL was stable in the capsular bag, showing no significant rotation up to 6 months postoperatively.

Conjunctival squamous cell carcinoma: atypical presentation of HIV.

Metastatic squamous cell carcinoma (SCC) of the conjunctiva is uncommon in Western countries. A Nigerian patient who presented with right lower lid swelling treated as a chalazion is described here. She re-presented 5 months later with widespread metastatic conjunctival SCC and positive HIV serology. Conjunctival SCC may be difficult to distinguish on clinical appearance alone and in an era of increasing global travel, young patients with a history of high ultraviolet-B radiation exposure and from countries with a high HIV prevalence should be given a low threshold for excision biopsy.