Alan P. Rotchford

Temba glaucoma study: a population-based cross-sectional survey in urban South Africa

OBJECTIVE To determine the prevalence and features of glaucoma in an urban South African black population. DESIGN Random sampling cross-sectional population survey. PARTICIPANTS Black residents of Temba, North West Province, South Africa, age > or =40 years. MAIN OUTCOME MEASURES Automated visual field testing and detailed, standardized slit-lamp examination were attempted on all subjects. Glaucoma was diagnosed by use of the scheme proposed by the Working Group for Defining Glaucoma of the International Society of Geographical and Epidemiologic Ophthalmology on the basis of evidence of end-organ damage. RESULTS Of 1120 subjects, 839 (74.9%) were examined. The age- and gender-adjusted prevalence of glaucoma of all types was 5.3% (95% confidence interval [CI], 3.9%-7.1%). Primary open-angle glaucoma (POAG) was the most common glaucoma diagnosis, with an adjusted prevalence of 2.9% (95% CI, 1.9%-4.3%). Secondary glaucoma occurred with an adjusted prevalence of 2.0% (95% CI, 1.2%-3.3%). Exfoliative glaucoma was responsible for 16% of all glaucoma cases. The prevalence of primary angle-closure glaucoma was 0.5% (95% CI, 0.13%-1.2%). Of all subjects with glaucoma, 58% were blind in at least one eye. The prevalence of all types of glaucoma increased with age. Of subjects with POAG, 87% had not been previously diagnosed. CONCLUSIONS The prevalence of glaucoma in this South African population was higher than that found in white populations, and most cases were undiagnosed and untreated. Glaucoma is a major cause of blindness in this population.

A novel use of amniotic membrane in the management of tube exposure following glaucoma tube shunt surgery

Aim: To report a novel technique using amniotic membrane to cover exposed glaucoma tube shunts. Methods: A consecutive series of three cases that underwent drainage tube shunt surgery with the Ahmed valve for intractable glaucoma. All three patients developed exposure of the tube secondary to necrosis of the overlying bovine pericardial patch and conjunctiva. Repair of the defect was carried out with a double layer of amniotic membrane, the inner one acting as a graft and the outer as a patch. Autologous serum was used to promote epithelial growth. Results: Successful lasting closure of the conjunctival defect was achieved in all cases. Conclusion: Erosion of the drainage tube following shunt surgery is a potentially serious problem. It can be successfully managed using a double layer of amniotic membrane.

The effect of corneal thickness on intraocular pressure measurement in patients with corneal pathology

Background/aim: To compare intraocular pressure (IOP) measurements taken by the Goldmann applanation tonometer, the Tono-Pen and the ocular blood flow pneumotonometer in eyes with varying central corneal thickness (CCT) due to penetrating keratoplasty (PK), keratoconus (KC), and Fuchs’ endothelial dystrophy (FED). Methods: IOP was measured with the Goldmann applanation tonometer, Tono-Pen XL, and OBF pneumotonometer in 127 eyes with the following corneal abnormalities. There were 56 eyes that had undergone PK, 37 eyes with KC, and 34 eyes with FED. CCT was measured using an ultrasound pachymeter after IOP determinations had been made. Results: Mean IOP measurements in all three patient groups were significantly higher when measured by OBF pneumotonometer. Linear regression analysis showed that patients with FED had a significant increase in IOP with increasing CCT of 0.18 mm Hg/10 μm using the Goldmann tonometer, 0.15 mm Hg/10 μm with the Tono-Pen, and 0.26 mm Hg/10 μm with the OBF pneumotonometer. In patients with KC and after PK, linear regression analysis did not show a significant effect of CCT on IOP. A multivariate linear regression model controlling for age, sex, graft size, and patient group, showed that the effect of CCT on IOP for Tono-Pen (0.13 mm Hg/10 μm CCT) and Goldmann (0.14 mm Hg/10 μm CCT) were significantly lower than for the OBF pneumotonometer (0.26 mm Hg/10 μm CCT). Conclusions: This study found that mean IOP measurements using the OBF pneumotonometer were significantly higher than those made using the Goldmann applanation tonometer or Tono-Pen in eyes with a variety of cornel pathologies. The OBF pneumotonometer was found to be most affected by variation in CCT. For all three instruments, the relation between IOP and CCT depended on the corneal pathology and was greatest for FED.

Frequency of bleb manipulations after trabeculectomy surgery

Aim: To quantify the type and frequency of postoperative bleb manipulations undertaken after modern glaucoma surgery. Methods: Bleb manipulations were recorded after trabeculectomy surgery on 119 consecutive patients with at least 1 year of follow-up. The type of intervention and time after surgery were recorded. Statistical analysis identified success rates at various intraocular pressure (IOP) cut-off definitions and identified factors that increased the risk for bleb manipulation. Results: In all, 78.2% of trabeculectomies were followed by some form of bleb manipulation. Almost 49% of blebs underwent massage and a similar number required at least one suture removal, 31.1% required at least one 5-fluorouracil (5-FU) injection and 25.2% required at least one needling and 5-FU injection. The median time to the first intervention for massage, suture removal, 5-FU injection, and needling and 5-FU injection were 1, 14, 14 and 43 days, respectively. IOP measurements were higher at all follow-up time points in the intervention group. Failure to achieve specific IOP target pressures was also generally poorer in the 5-FU, and needling and 5-FU intervention groups. Conclusions: Postoperative intervention is a frequent occurrence after modern glaucoma surgery. This requires intensive postoperative follow-up and is a labour-intensive undertaking. Despite interventions in our group of patients, IOP in the intervention group was always higher than in the group that required no intervention.

First day review after uncomplicated phacoemulsification: is it necessary?

Purpose To determine whether first day follow-up is necessary after routine uncomplicated phacoemulsification cataract surgery. Methods Data collected prospectively at day 1 postoperative review. Results In 510 consecutive cases, serious complications occurred in 8 (1.6%) (wound leak [4], corneal abrasion [2], iris prolapse [1], hyphema [1]). Intraocular ptessure (IOP) >30 mmHg was found in 26 (5.1%) and was strongly associated with a diagnosis of pre-existing glaucoma or ocular hypertension (odds ratio [OR] 7.7). Symptoms of headache or ocular discomfort occurred in 40 (7.8%), mostly in association with raised IOP, and were also associated with pre-existing glaucoma or ocular hypertension (OR 4.7). Central corneal edema was found in 61 (12.0%). In the absence of corneal edema, IOP was >30 mmHg in only two cases (0.39%). Conclusions Few sight-threatening complications were detected on the morning after an uncomplicated procedure. First day follow-up may be safely omitted if adequate patient counseling is undertaken and there is provision of adequate access to eye services. Review prior to discharge on the day of surgery would provide an opportunity to detect these few surgical complications and for counseling. A diagnosis of glaucoma or ocular hypertension is a risk factor for significantly raised next day IOP and these patients are more likely to experience postoperative discomfort. They may benefit from prophylactic treatment.

Epithelial proliferative potential of organ cultured corneoscleral rims; implications for allo-limbal transplantation and eye banking

Aims: To determine the epithelial proliferative capacity of organ cultured limbal tissue and correlate this with various donor and eye banking factors. Methods: 24 corneoscleral limbal (CSL) rims left over from penetrating keratoplasty were split in half and set up as in vitro explant cultures. Corneal epithelial proliferative potential (CEPP) was assessed by the number of “cycles” of growth achieved before explants underwent exhaustion and failure to generate an epithelium to subconfluence. The dependence of CEPP on the age of the donor, time of death to enucleation, time of enucleation to organ culture, and time in organ culture in the eye bank was determined. Results: CSL rims were capable of up to four cycles of culture with a wide variation between tissue samples. Of the various factors examined, death to enucleation time was the only statistically significant factor affecting the CEPP (regression coefficient: −0.062 (cycles/hour), CI −0.119 to −0.004, p  = 0.037). Time in organ culture had little effect on CEPP. Conclusions: Preselected organ cultured CSL rims from eye banks may offer a viable alternative tissue source for use in allo-limbal transplantation.

Severe decompression retinopathy after medical treatment of acute primary angle closure

We describe a case of medically treated acute primary angle closure (APAC) resulting in severe visual loss owing to retinal haemorrhage. We are unaware of previous reports on this phenomenon in the world literature. A 65-year-old woman visited her optometrist for a routine check. Her pupils were dilated and no pathology was found. Her vision progressively deteriorated that evening. She attended the hospital and was noted to have unreactive mid-dilated pupils bilaterally. Visual acuity was 20/60 OU (pinhole). Intraocular pressure (IOP) was 60 mm Hg OD and 66 mm Hg OS. Gonioscopy showed occluded angles. The patient had moderate hypermetropia but otherwise had no other ocular risk factors for angle closure. A diagnosis of iatrogenic APAC was made and the patient was given intravenous acetazolamide, topical dexamethasone, iopidine 1% and pilocarpine 4%. Ninety min later, IOPs was found to …

24-Hour versus daytime intraocular pressure phasing in the management of patients with treated glaucoma

Aims To determine the value of daytime and 24-h phasing in patients treated for progressive glaucoma despite apparently adequate intraocular pressure (IOP) control. Methods A retrospective analysis of a cohort of patients that had undergone either daytime phasing (08:00–18:00) or 24-h phasing was conducted. IOP measurements were compared between those taken in clinic, daytime phasing and 24-h phasing. The frequency with which phasing results changed clinical management was also compared between daytime and 24-h phasing. Results 76 patients fulfilling the study criteria were identified. Clinic and daytime phasing IOP were known for all 76 patients, nighttime IOP measurements were known for 41. There was no significant difference between mean IOP values measured in clinic and daytime phasing (p=0.062) or between clinic values and nighttime phasing (p=0.65). The mean daytime phasing IOP was significantly higher than the mean nighttime phasing IOP (p=0.038) (analysis of variance (ANOVA) for three groups, p=0.058). There was no significant difference between the mean peak IOP in clinic or daytime phasing (p=0.13) or between clinic and nighttime phasing (p=0.44). The mean daytime phasing IOP peak was significantly higher than the mean nighttime phasing IOP peak (p=0.015) (ANOVA for three groups, p=0.074). There was no significant difference in the frequency of a change in management that occurred as a result of phasing between the daytime and 24-h groups (p=0.65). Conclusions 24-H phasing offers little advantage over daytime phasing in the identification of IOP fluctuations or peaks in patients progressing despite acceptable clinic IOP readings. Daytime phasing is likely to be more cost-effective than 24-h phasing.

Factors influencing poor visual outcome in patients treated with photodynamic therapy for choroidal neovascularization secondary to age-related macular degeneration.

Background:  This study evaluated patients with choroidal neovascular membranes secondary to age‐related macular degeneration for factors that may predict the visual outcome after photodynamic therapy.

Primary low-risk trabeculectomy augmented with low-dose mitomycin-C

Purpose To present outcome data on low risk primary trabeculectomy augmented with low dose peroperative (0.1 mg/mL for 1 minute) mitomycin-C (MMC). Methods Retrospective case note review. All cases of trabeculectomy utilizing MMC augmentation at a concentration of 0.1 mg/mL with an application time of 1 minute and at least 1 year follow-up during the study period were included. Only first eyes were included. Patient demographics and postoperative course including complications, interventions, and outcomes were documented and analyzed. Results Fifty-nine trabeculectomies that met the inclusion criteria were identified. Mean age of cases was 70.8 years. Mean follow-up time was 19.3 months. Bleb leaks occurred in 16 (27.1%) cases. Only one case required surgical intervention in the form of resuturing after 14 days. At 1 year, there was a reduction in mean number of topical medications from 2.70 to a mean of 0.07. Unqualified success (intraocular pressure [IOP] at 1 year of less than 16 mmHg without medication) was achieved in 49 cases (83.1%). Mean IOP was reduced from the preoperative value of 23.1 mmHg (SD 5.8) to 13.5 mmHg (SD 5.0) (p<0.001). Conclusions Our data suggest that a primary trabeculectomy augmented with a low dose of MMC is a safe and effective procedure for IOP reduction in patients with a low risk of trabeculectomy failure.