Conjunctival impression cytology for vitamin A deficiency in the presence of infectious trachoma

BACKGROUND/AIMS—Increased morbidity and mortality from a number of infectious diseases have been associated with vitamin A deficiency. Trachoma and vitamin A deficiency are both important causes of blindness in Nepal. The purpose of this study was to determine the association between the diagnosis of vitamin A deficiency by conjunctival impression cytology and the diagnosis of infectious trachoma by the polymerase chain reaction (PCR) in the Lumbini zone of Nepal.
METHODS—70 children under the age of 11 in a rural village in the Lumbini zone were examined for clinical evidence of active trachoma. The conjunctiva of each child was tested for ocular Chlamydia trachomatis infection using PCR, and for loss of goblet cells (a sign of subclinical vitamin A deficiency) using conjunctival impression cytology.
RESULTS—The presence of infectious trachoma was associated with the loss of goblet cells on conjunctival impression cytology (p=0.02). This relation was present and significant even when adjusted for age (p=0.05) and degree of inflammation (p=0.02). In fact, even subclinical infection with chlamydia was associated with an abnormal conjunctival impression cytology (p=0.02).
CONCLUSIONS—Children with infectious trachoma are significantly more likely to have an abnormal conjunctival impression cytology, even if the infection is subclinical. Thus, the diagnosis of vitamin A deficiency from conjunctival impression cytology alone should be made with some caution in areas with endemic trachoma. Further studies will be needed to determine the cause of this association.

Keywords: trachoma; vitamin A; impression cytology; chlamydia     

Diagnosis of Fusarium keratitis in an animal model using the polymerase chain reaction

AIMS/BACKGROUND—The purpose of this study was apply the polymerase chain reaction (PCR) to develop a sensitive, specific, and rapid test to diagnose Fusarium keratitis. Fusarium is the most common cause of fungal corneal infection in some parts of the world. It is often difficult to establish that a keratitis is due to fungal infection.
METHODS—Fusarium solani keratitis was induced in three eyes of three rabbits by injection of a suspension of the fungus into the anterior corneal stroma. In one rabbit the contralateral eye served as a control. From four to 28 days after inoculation, the corneas were scraped for culture, then scraped and swabbed for PCR analysis. The PCR was performed with primers directed against a portion of the Fusarium cutinase gene, and the presence or absence of this amplified target sequence was determined by agarose gel.
RESULTS—The amplified DNA sequence was detected in 25 of 28 samples from the corneas infected with Fusarium, for a sensitivity of 89%. Only three of the 14 samples from these eyes with Fusarium keratitis were positive by culture, for a sensitivity of 21%. Seven of eight control samples were negative by the PCR based test, for a specificity of 88%.
CONCLUSION—This PCR based test holds promise of being an effective method of diagnosing Fusarium keratitis as well as Fusarium infections at other sites.

Keywords: keratitis; Fusarium; ulcer; cornea; polymerase chain reaction     

Detection of human papillomavirus infection in squamous tumours of the conjunctiva and lacrimal sac by immunohistochemistry, in situ hybridisation, and polymerase chain reaction

BACKGROUND—Squamous tumours of the ocular surface, including the lacrimal pathway, range from benign lesions to invasive carcinomas. Some of these tumours are associated with human papillomavirus (HPV) infection, with the types of HPV differing among papillomas and dysplastic or malignant lesions.
METHODS—The relation between squamous tumours of the conjunctiva and lacrimal sac and HPV infection was investigated in 17 individuals with such tumours. Nine of the 17 tumours were benign, four were dysplastic lesions, and four were carcinomas.
RESULTS—Eight specimens showed positive immunohistochemical staining with antibodies to HPV; four of these eight were papillomas, three were dysplastic lesions, and one was a carcinoma. Koilocytosis was detected in seven of these eight tumours. Five of the eight specimens positive for immunohistochemical staining were also positive for HPV DNA by in situ hybridisation, and all eight were positive for HPV DNA by the polymerase chain reaction (PCR) method.
CONCLUSION—Approximately 50% of squamous tumours of the ocular surface and lacrimal sac were associated with HPV infection. This is the first report, to our knowledge, of the detection of HPV in the field of ophthalmology by a combination of immunohistochemistry, in situ hybridisation, and PCR.

     

Chorioretinal post-transplant lymphoproliferative disorder induced by the Epstein-Barr virus

BACKGROUND—The Epstein-Barr virus (EBV) is responsible for the lymphoproliferative disorders observed in transplanted patients.
METHODS—The case history is described of a 59 year old man with a chorioretinal lesion who had received a single lung transplant and was on immunosuppressive treatment. Immunoglobulin gene rearrangement and EBV detection by polymerase chain reaction (PCR) with semiquantification were used on the vitreous material.
RESULTS—A proliferation of B lymphocytes with a monoclonal subpopulation was found by PCR on the vitreous sample. The large amounts of EBV genomes found in the vitreous suggest that EBV was the cause of the lymphoproliferation. Healing of the lesion was achieved by a decrease in immunosuppressive treatment and the use of nucleotide analogues.
CONCLUSION—The diagnosis of ocular post-transplant lymphoproliferative disorder (PTLD) can be made by PCR on vitreous material. Early diagnosis and treatment can lead to regression of limited monoclonal lesions.

     

Polymerase chain reaction in the diagnosis of bacterial endophthalmitis

BACKGROUND—Microbiological investigations of vitreous fluid (VF) and aqueous humour (AH) specimens have often failed to detect the infecting agent in infectious endophthalmitis, resulting in a clinical dilemma regarding therapy. In this study, the polymerase chain reaction (PCR) was evaluated in the diagnosis of bacterial and Propionibacterium acnes endophthalmitis.
METHODS—58 intraocular specimens (30 VF and 28 AH) from 55 cases of endophthalmitis and 20 specimens (14 VF and 6 AH) as controls from non-infective disorders were processed for microbiological investigations. Nested PCR directed at the 16S rDNA using universal primers for eubacterial genome was done. PCR for P acnes was performed on specimens microbiologically negative by conventional techniques but eubacterial genome positive.
RESULTS—Of the 20 controls from non-infective cases, one (5%) was positive using eubacterial primers and none with P acnes primers. PCR for eubacterial genome showed 100% correlation with 20 (34.5%) bacteriologically positive specimens. Eubacterial genome, was detected in 17 (44.7%) of 38 bacteriologically negative specimens and nine (52.9%) out of the 17 were positive for P acnes genome. Among the 21 eubacterial PCR negative specimens, seven were fungus positive. By inclusion of PCR, microbiologically positive specimens increased from 46.5% to 75.8%. PCR on AH was as sensitive as that on VF for the detection of both eubacterial and the P acnes genome.
CONCLUSION—PCR performed on AH and VF is a reliable tool for the diagnosis of bacterial and P acnes endophthalmitis particularly in smear and culture negative specimens.

Keywords: polymerase chain reaction; bacterial endophthalmitis; infectious endophthalmitis     

Urinary neopterin in idiopathic retinal vasculitis

AIMS—To determine whether urinary neopterin:creatinine (UNC) ratios relate to disease activity in idiopathic retinal vasculitis (RV).
METHODS—18 patients with RV were prospectively recruited into a year long longitudinal study. Patients collected first morning urine samples on a weekly basis and on the same day completed a diary which documented their subjective view of RV activity and any concurrent infection. They were examined in clinic on a 6-8 weekly basis and an objective assessment was made of RV disease activity. 14 healthy controls collected urine samples in the same way.
RESULTS—UNC ratios were significantly higher in patients than in controls (p=0.004, Mann-Whitney U test). UNC ratios were significantly higher when, according to their diaries, the patients had a subjective flare up of RV (p=0.001, Mann-Whitney U test). Subjective increased RV activity occurred more often when the patients had a concurrent infection (p<0.0001, χ² test). There was no significant difference in the UNC ratio between objective clinical relapse and non-relapse of RV. There was moderate agreement between the clinical assessment and patients' subjective impression of RV activity (κ=0.48).
CONCLUSIONS—Higher neopterin levels reflect cell mediated disease that occurs in RV, but UNC ratios are not recommended as a means of monitoring clinical disease activity in RV.

     

Cataract progression in India

AIMS—The study was undertaken to test the feasibility of using the LOCS III cataract grading scale in the field and to determine the rate of cataract progression over a 1 year period of time.
METHODS—For 150 subjects between the ages of 33 and 55 who attended the refraction clinic at Aravind Eye Hospital in Madurai, India, lens abnormalities were graded at the slit lamp using the LOCS III scale. One year later, 99 of the subjects were re-evaluated by the same methodology to assess the amount of lens change.
RESULTS—Interrater reliability was high. A change of 0.5 or more in lens colour, cortical, nuclear, or posterior subcapsular cataract was observed in at least one eye of 54% of the subjects.
CONCLUSION—The LOCS III grading scale is a feasible method for measuring lens changes in the field with the slit lamp. Cataract progression in India is rapid enough to permit intervention studies to be performed with relatively small numbers of subjects over a short period of time (that is, 600 subjects for 2 years).

     

Endogenous cortisol profile in patients with central serous chorioretinopathy

AIM—To study the endogenous cortisol levels in patients with central serous chorioretinopathy (CSCR).
METHODS—Endogenous cortisol levels in urine and plasma were determined in 30 patients with acute CSCR and compared with 30 age and sex matched controls.
RESULTS—The mean values of the 8 am plasma cortisol (29.97 µg/dl v 18.76 µg/dl), 11 pm plasma cortisol (22.03 µg/dl v 13.06 µg/dl), and 24 hour urine cortisol (11.01 mg/24 h v 7.39 mg/24 h) revealed significantly higher values in the patient group (p<0.001).
CONCLUSIONS—Increased levels of endogenous cortisol are present in patients with CSCR.

     

Incidence of delayed onset infection after trabeculectomy with adjunctive mitomycin C or 5-fluorouracil treatment

AIMS/BACKGROUND—The introduction of the adjunctive use of antiproliferatives to trabeculectomy has greatly improved the success rate of this operation. Trabeculectomy with antiproliferative treatment, however, is usually associated with a cystic and thin walled filtering bleb, which may be more susceptible to infection. The objective of this study was to evaluate the incidence, clinical findings, and risk factors of delayed onset, bleb related infection after trabeculectomy with adjunctive mitomycin C (MMC) or 5-fluorouracil (5-FU) treatment.
METHODS—The records of 632 glaucoma patients who underwent 966 trabeculectomies, with and without the use of adjunctive MMC or 5-FU treatment, between January 1985 and February 1995 were analysed. The mean follow up period was 3.5 (2.4) years (range 0.1 to 11.2 years). The mean patient age was 54.8 (18.8) years (range 0 to 88 years).
RESULTS—Bleb related infection occurred in one of 76 trabeculectomies that did not receive antiproliferatives (1.3%), three of 228 treated with 5-FU (1.3%) trabeculectomies, and seven of 662 treated with MMC (1.1%). Five eyes developed blebitis; six eyes developed endophthalmitis. Bleb related infection developed an average of 3.1 (1.6) (range 0.4 to 6.0) years after trabeculectomy. All eyes had avascular or hypovascular blebs that were cystic in shape before infection and all eyes had reduced intraocular pressure. Early wound leaks and chronic, intermittent bleb leaks were identified to be risk factors for the bleb related infection.
CONCLUSION—The incidence of delayed onset, bleb related infection after trabeculectomy with antiproliferative treatment is similar to that after trabeculectomy without antiproliferatives.

     

Intraocular lens durability after a mean of 10.9 years' implantation in humans

AIMS/BACKGROUND—To clarify whether intraocular lens (IOL) implantation in the human eye affects the durability of polymethylmethacrylate over an average period of 10.9 years.
METHODS—Shearing stress and extent of damage following neodymium (Nd):YAG laser application to 18 study and 12 control optics were examined.
RESULTS—No significant difference was found between the study and the control IOLs in shearing stress and extent of damage following Nd:YAG.
CONCLUSION—An average 10.9 years' implantation in humans does not affect either the shearing stress or extent of damage following Nd:YAG shots of polymethylmethacrylate.

     

Screening for amblyopia: a comparison of paediatric letter tests

AIMS/BACKGROUND—The measurement of visual acuity is the most widely accepted indicator of amblyopia and is thought by some to be the only effective screening test. The aim of this study was to investigate the effectiveness of the traditional single optotype Sheridan-Gardiner test (SGT) in the measurement of visual acuity and the detection of amblyopia, compared with the log based linear format Glasgow acuity cards (GAC).
METHODS—In the present study visual acuity was measured monocularly in 702 primary 1 schoolchildren using both acuity tests.
RESULTS—A significant difference was found in the mean (SD) visual acuity measured with GAC (0.9 (0.08) modified logMAR) and SGT (1.13 (0.09) modified logMAR), df=632, t=−59.08, p=0.0001. The majority of children (89.3%) achieved visual acuities better than 6/6 in either eye when using the single optotype test. If the 95% confidence limits for a significant interocular difference in acuity are used as criteria for the detection of unilateral amblyopia, GAC were found to be the most sensitive, correctly identifying 100%, while SGT identified 55% of the children with unilateral amblyopia.
CONCLUSION—The results of this study highlight several problems with both the test format and testing procedure in the present school screening system.

     

Clinical experiences of infectious scleral ulceration: a complication of pterygium operation

AIMS—To report the special clinical manifestations and determine the appropriate management of infectious scleral ulceration.
METHODS—A retrospective study was performed on 30 eyes with infectious scleral ulceration. Information was recorded on patients' age, onset and course of disease, pathogenic organism, clinical presentations, methods of diagnosis, treatment, and outcome.
RESULTS—10 cases (33.3%) were accompanied by corneal involvement. Subconjunctival abscess was noted in 16 cases (53.3%). 17 cases (56.7%) gave positive results of pathogen culture and all were Pseudomonas aeruginosa. Two cases had combined bacterial infections and one case was complicated by fungal infection. A total of 26 cases had surgical debridement in this series. Extensive involvement of the sclera with the presence of a `tunnel lesion' or a `satellite subconjunctival abscess' were found during debridement. All of the eyeballs involved were salvaged except one.
CONCLUSION—The results of this study were contrary to the poor prognosis presented in previous reports. Early and repetitive surgical debridement is believed to be mandatory in the intractable cases to shorten the admission period and to save these eyes.

     

A randomised prospective comparison of operative peripheral iridectomy and Nd:YAG laser iridotomy treatment of acute angle closure glaucoma: 3 year visual acuity and intraocular pressure control outcome

AIM—To compare visual acuity and intraocular pressure outcomes 3 years after treatment of acute angle closure glaucoma (AACG) by operative peripheral iridectomy (PI) or Nd:YAG laser iridotomy (YAG PI).
METHODS—A prospective study of consecutive patients presenting to one ophthalmology department with uniocular AACG during a 2 year period. Following informed consent patients were randomised to bilateral PI or bilateral YAG PI. Three years after treatment the mean Snellen visual acuity converted to logMAR scores of the two groups was compared using the unpaired Student's t test. The number of patients with normal intraocular pressure with no further treatment in each group was compared using the χ² test with Yates's correction.
RESULTS—21 patients underwent bilateral PI and 27 bilateral YAG PI. Three years after treatment visual acuity was 0.30 (SD 0.28) log MAR units for PI eyes and 0.57 (0.67) logMAR units for YAG PI eyes (p=0.08, NS). 15 (70.4%) PI eyes and 19 (71.8%) YAG PI eyes had an intraocular pressure less than 21 mm Hg with no further treatment (NS).
CONCLUSIONS—There was no significant difference in visual acuity or intraocular pressure control 3 years after treatment of AACG with PI or YAG PI.

     

Ocular changes associated with Giardia lamblia infection in children

BACKGROUND—The protozoan disease giardiasis can cause ocular complications, including "salt and pepper" retinal changes.
METHODS—Ophthalmic examinations were performed in 141 children (mean age 4.7 (SD 2.0) years) with active or past giardiasis diagnosed on the basis of microscopic examination of stool specimens or duodenal secretions—53 were newly diagnosed and untreated (group A), 50 had active infections in spite of metronidazole therapy (group B), and 38 had been successfully treated, with negative stool specimens for 1-3 years (group C). 300 children with no evidence of giardiasis were used as controls.
RESULTS—Salt and pepper retinal changes (with normal electroretinographic findings) were diagnosed in 28 (19.9%) of the patients with giardiasis (11 from group A, 10 from group B, and seven from group C), including five pairs of siblings. In all subgroups, the children with retinal changes were consistently younger than those with normal retinas. In eight cases, the lesions could be visualised only with direct ophthalmoscopy.
CONCLUSION—Our findings indicate that asymptomatic, non-progressive retinal lesions are particularly common in younger children with giardiasis. This risk does not seem to be related to the severity of the infection, its duration, or the use of metronidazole but may reflect a genetic predisposition.

Keywords: gastrointestinal disease; Giardia lamblia; eye; retina     

Influence of patient age on refraction and corneal haze after photorefractive keratectomy

AIMS/BACKGROUND—Since wound healing processes are known to be more rapid in those who are young, it was decided to examine the effect of patient age on refractive outcome of photorefractive keratectomy (PRK).
METHODS—The records of 599 eyes that had undergone PRK were studied retrospectively. The eyes were categorised by baseline myopia and patient age. Spherical equivalent and corneal haze were compared in the baseline refraction and age groups at 3, 6, and 12 months after PRK.
RESULTS—There were no differences in postoperative refraction and corneal haze in the different age groups.
CONCLUSION—Patient age had no statistically significant effect on refraction and corneal haze 1 year after PRK.

     

Predictive factors for the development of rubeosis following proton beam radiotherapy for uveal melanoma

AIMS/BACKGROUND—Proton beam radiotherapy can effectively treat primary uveal melanomas of any size. Some patients, however, develop adverse late effects following treatment and the purpose of this study was to determine which factors give rise to a poor local outcome.
METHODS—The hospital records from a first cohort of 127 patients treated by protons from 1989 to 1992 were reviewed retrospectively. The presence of rubeosis was selected as a measure of significant ocular damage. Split file analysis was performed with 73 cases forming a test group with the remaining 54 cases acting as a validation group.
RESULTS—Large tumour size and the presence of retinal detachment were significant, independent risk factors for developing rubeosis for both the test and validation groups. These factors also predicted subsequent enucleation for uncontrolled ocular pain. Patients with tumours too large to plaque and with an associated retinal detachment had a 90% chance of developing rubeosis within 4 years of proton beam radiotherapy.
CONCLUSIONS—Patients with a uveal melanoma too large for plaque therapy and an associated retinal detachment run a very high risk of developing rubeosis after proton beam radiotherapy and one third of individuals developing rubeosis required enucleation for pain even if local tumour control was satisfactory.

     

Intrascleral dissemination of infectious scleritis following pterygium excision

AIMS—To assess the clinical pictures, possible pathogenesis, management, and therapy of patients with infectious scleritis associated with multifocal scleral abscesses following pterygium excision.
METHODS—The records of patients with infectious scleritis after pterygium excision who developed multifocal scleral abscesses presenting from 1988 to the end of 1995 were reviewed. Early culture of abscesses was performed, and topical, systemic antimicrobials, or both were given to all patients. Fourteen eyes were operated on in addition to antimicrobial treatment.
RESULTS—The initial culture reports of scleral ulcers identified Pseudomonas species in 12 of these 18 patients, Aspergillus in one, Mycobacterium fortuitum in one, and mixed organisms in four. Subsequent abscess cultures were taken from 15 of the infected eyes, and revealed the same organism as the initial culture in 12. Associated complications included four serous retinal detachments, three choroidal detachments, two double detachments, five complicated cataracts, and four recurrences of the initial infection. Four eyes required eventual enucleation and 11 eyes regained useful vision.
CONCLUSIONS—With subsequent abscess cultures proving to be the same organism as found in the initial ulcer, the abscess formation appears to represent intrascleral dissemination. Early diagnosis and appropriate, prolonged topical plus systemic antimicrobial treatment are essential to halt the progression of such severe infections.

Keywords: infectious scleritis; scleral abscess; pterygium excision     

Influence of topical human epidermal growth factor on postkeratoplasty re-epithelialisation

AIM—To test the efficacy and safety of recombinant human epidermal growth factor (hEGF) on corneal re-epithelialisation following penetrating keratoplasty.
METHODS—A prospective, randomised, placebo controlled study was carried out in which patients were matched for diagnosis and received either hEGF ophthalmic solution (30 µg/ml or 100 µg/ml) or placebo in a double masked fashion. Matched pairs of patients received donor corneas from the same donor and were operated by the same surgeon on the same day. At the end of surgery all donor epithelium was removed mechanically. Patients were examined twice daily and fluorescein stained photographs were taken until the epithelium had closed. The area of the defect was measured by planimetry of the fluorescein stained defect on the photographs.
RESULTS—There were no significant differences in re-epithelialisation of the donor cornea between the placebo group and the group treated with 30 µg/ml hEGF. Time until complete closure was slightly longer with 100 µg/ml hEGF compared with 30 µg/ml hEGF and with placebo. Mean healing rate of the epithelial defect with 100 µg/ml hEGF was significantly slower than in the other groups.
CONCLUSION—No significant acceleration of corneal re-epithelialisation was demonstrated with the use of recombinant hEGF after penetrating keratoplasty in humans.

     

Ultrasound biomicroscopic measurement of anterior chamber angle in premature infants

AIM—To establish normative values for the anterior segment in premature infants in relation to postconceptional age and birth weight.
METHODS—Anterior segments were measured in 39 premature infants, 25 to 39 weeks' gestational age by use of ultrasound biomicroscopy and a muscle hook with topical anaesthesia.
RESULTS—Anterior chamber depth, trabecular-iris angle, angle opening (trabecular-iris) distances at 250 and 500 µm from the scleral spur, and the thickness of the thickest part of the iris showed linear increases in relation to postconceptional age and birth weight.
CONCLUSIONS—Ultrasound biomicroscopy is a powerful tool for obtaining precise images and measurement of the anterior segment in preterm neonates. Normative values were established for anterior segment dimensions in relation to postconceptional age and birth weight.

     

Triple procedure; analysis of outcome, refraction, and intraocular lens power calculation

AIMS—A total of 97 triple procedures performed over a 6 year period were studied retrospectively to determine the best approach to calculate intraocular lens power.
METHODS—The cases were divided into two diagnostic categories.
RESULTS—After 1 year best corrected visual acuity was 20/40 or better in 37.5% of the cases of the `modified group'. This group consists of patients with the diagnosis Fuchs' dystrophy, non-guttate endothelial dystrophy, and Reis-Buckler dystrophy. Analysis of visual acuity was made using logMAR. A final postoperative refraction within 2 dioptres of predicted refraction was achieved in 76.5% of patients in the modified group.
CONCLUSION—In future, in the absence of a keratometry, a keratometry value of 7.49 mm will be used for calculation of the power of the implant as analysed in this study.