Comparisons of intraocular pressure measurements: Goldmann applanation tonometry, noncontact tonometry, Tono-Pen tonometry, and dynamic contour tonometry.

AIMS: To compare intraocular pressure (IOP) readings between Tono-Pen tonometry and GAT, between noncontact tonometry (NCT) and GAT, and between dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT). The correlation between IOP reading and possible confounder was identified. METHODS: This observational cross-sectional study enrolled sixty-two healthy subjects. All IOP and ocular pulse amplitude (OPA) measurements were taken by a single ophthalmologist; mean keratometric power (MK), central corneal thickness (CCT), and lens thickness (LT) were measured by a single experienced technician. RESULTS: Stepwise multiple regression analysis indicated that GAT (P=0.017) and DCT (P=0.002) readings correlated positively with MK; GAT, NCT, and Tono-Pen readings correlated positively with CCT (P<0.05); NCT (P=0.035), and DCT (P=0.016) readings correlated negatively with LT; GAT (P=0.006) and Tono-Pen (P=0.009) readings correlated positively with OPA. CONCLUSIONS: The K, CCT, LT, and OPA are confounders in tonometry readings.

Screening amblyopia of preschool children with uncorrected vision and stereopsis tests in Eastern Taiwan.

UNLABELLED: AIMS OR PURPOSE: Screening for amblyopia at earliest age is important for early treatment and better prognosis. This study aimed at evaluating the validity of uncorrected distant and near visual acuity and random dot stereopsis for screening amblyopia. METHODS; In Eastern Taiwan, population-based screen tests were performed for children at age from 3 to 6 years. The tests included uncorrected distant and near visions and random dot stereopsis (300 s) test. The screen performers were registered nurses of local public health service posts. The golden standards of the tests were the results of examination by the ophthalmologists. RESULTS: Including Hans and aboriginal Taiwanese, 5232 children were included. Screened by distance visual acuity with different cutoffs and near visual acuity, 10.3, 30.3 and 8.2% children were abnormal. Screened by random dot, only 2% children were abnormal. By a senior ophthalmologist, 115 amblyopic children were diagnosed amblyopic. The sensitivities of distance visual acuity with low/high cutoff and near visual acuity were 74.7/84.8 and 49.4%, whereas that of the NTU random dot stereogram was 20.5%. Simultaneous testing of either two of the three tests improved the sensitivity. CONCLUSION: Screening for amblyopia by the local nurses using the visual acuity tests or random dot stereopsis test alone does not display a high sensitivity. Simultaneous testing of distant visual acuity and stereopsis test elevate the sensitivity and preserve the specificity.

Genetic analysis of recent Taiwanese isolates of a variant of coxsackievirus A24.

Epidemics of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v) reappeared in Taiwan in 1990 and 1994, following the first two epidemics of 1985--86 and 1988--89. To analyze the genetic diversity of recent CA24v in Taiwan, 7 Taiwanese strains isolated during the 1990--94 period were studied together with one Japanese and two Thai strains isolated in 1993. A fragment of 674 nucleotides between the carboxy terminal 3A and the amino terminal 3D polymerase, including the entire 3C protease (3C(pro)), was amplified by a reverse transcription-polymerase chain reaction (RT-PCR) and the nucleotide sequences were determined. In the 549 nucleotides (183 amino acids) of the entire 3C(pro), we found nucleotide differences at 80 positions between 10 strains and the prototype strain, EH24/70, one of the earliest strains of CA24v. Most of the nucleotide changes were synonymous substitutions and only nine amino acid changes were found. The nucleotide sequence homologies among 71 strains worldwide were 88-100%. These 71 nucleotide sequences were then analyzed by Neighbor-joining method and phylogenetically separated into three distinct genotypes. Genotype I consisted of early strains isolated in 1970--71 from Singapore and Hong Kong. Genotype II included isolates from Singapore and Thailand obtained in 1975. Genotype III comprised strains from the eastern hemisphere isolated in 1985--94 from Japan, Taiwan, China, Hong Kong, Thailand, Singapore, Pakistan and Ghana. They were further divided chronologically into six clusters. The recent isolates from Taiwan obtained in 1985/1986, 1988/1989 and 1990--94 were classified into genotype III Clusters 1, 5, and 6 respectively. The evolutionary rate was re-estimated to be 3 x 10(- 3) 30 years after the emergence of the virus.

Hemorrhagic viral keratoconjunctivitis in Taiwan caused by adenovirus types 19 and 37: applicability of polymerase chain reaction-restriction fragment length polymorphism in detecting adenovirus genotypes.

PURPOSE: Acute keratoconjunctivitis with prominent subconjunctival hemorrhage (SCH) is usually perceived by a clinician as acute hemorrhagic conjunctivitis (AHC) associated with enteroviruses; however, SCH can also be an adenoviruses infection. A rapid and sensitive laboratory diagnosis is helpful for differential diagnosis. Therefore, the sensitivity and applicability of polymerase chain reaction (PCR) and reverse transcription (RT)-PCR diagnoses were evaluated for keratoconjunctivitis associated with viral infection. METHODS: Conjunctival swabs from patients with acute conjunctivitis were tested using a PCR-restriction fragment length polymorphism (PCR-RFLP) for adenovirus detection and RT-PCR for enterovirus detection. The results were compared with those using the culture isolation and neutralization test; also, the clinical findings of the patients were analyzed with special attention to SCH patterns. RESULTS: Neither coxsackievirus A type 24 variant (CA24v) nor enterovirus type 70 (EV70) was detected in 113 patients with acute conjunctivitis. The positive results of adenovirus (Ad) were 39.9% by the PCR method and 37.1% by culture isolation. For the patients with adenoviral conjunctivitis, 68.1% was owing to Ad37 and 19.2% was owing to Ad19. SCH was present in 51.5% of the positive cases, and 44.7% of the Ad-positive patients had secondary illnesses. CONCLUSIONS: SCH can be a predominant presentation of Ad19 and Ad37 keratoconjunctivitis and may herald a new stage in the evolution of adenoviruses. PCR and PCR-RFLP are rapid and reliable methods for Ad detection and typing; however, if the amplified genes and restriction enzymes are not properly selected, they may not be able to detect new genotypes of adenoviruses or the evolution of these viruses.

Efficient diagnosis of dengue infections using patients' peripheral blood leukocytes and serum/plasma.

OBJECTIVE: Dengue fever has been one of the most important health problems in Taiwan since a large outbreak during 1987 and 1988. It is critically necessary to have a diagnostic approach that can detect early infections in an outbreak or even find infections existing in silent transmission of the disease. METHODS: To develop an efficient diagnostic protocol, 105 plasma/serum and 35 peripheral blood leukocyte (PBL) specimens from the 1994 outbreak in southern Taiwan were collected for assessment by various diagnostic techniques in this study. RESULTS: In acute blood samples, dengue viruses were isolated from 19.4% (14/72) and 33.3% (14/42) of reported and confirmed cases, respectively. Viral RNA in serum/plasma was detected from 20.0% (12/60) of acute samples, which was significantly higher than that from convalescent samples (3/44; 6.8%). However, viral RNA in PBLs, detected by reverse transcription polymerase chain reaction (PBL-RT-PCR), could be observed in 73.2% (19/26) and 66.7% (6/9) of acute and convalescent samples, respectively. The persistence of dengue viruses in PBLs was also evidenced by the presence of viral antigens in 42.9% (4/7) of confirmed convalescent samples by the immunofluorescence antibody test. In addition, IgM antibodies were detected in 43.8% (46/105) of reported cases and 85.2% (46/54) of confirmed cases by the IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA). CONCLUSIONS: Although IgM antibody detection achieved the highest detection rate among techniques assessed in this study, no individual test can actually reach full efficiency for early diagnosis of dengue infections. Here, we propose a protocol which applies MAC-ELISA and PBL-RT-PCR in sequence, by which 22 confirmed cases were definitely proved as dengue positive. High levels of both sensitivity and specificity were shown in this protocol.

Intraocular use of fluconazole in the management of ocular fungal infection.

In this study, we investigate the efficacy and safety of intraocular use of fluconazole in the treatment of ocular fungal infection. Ten patients with intraocular fungal infections were examined. Among these patients, eight were infected with keratomycosis with intraocular spreading, one had postoperative fungal endophthalmitis after cataract operation with an intraocular lens implant, and another suffered from endogenous fungal endophthalmitis. In addition to the conventional local application with or without systemic administration of antifungal drugs, all ten patients were treated with intraocular administration of 5-10 micrograms/ml of fluconazole. The ocular fungal infections resolved in nine patients without obvious side effect. One failed in the antifungal treatment with loss of vision. In our experience, the results revealed that fluconazole is a safe and effective antifungal agent that can be administered intraocularly. We suggest that intraocular administration of this drug could be considered as an alternative or additional choice for the treatment of severe ocular fungal infections.

Fungal keratitis caused by Candida utilis--case report.

We report the first case of an ocular fungal infection caused by Candida utilis in a 72-year-old woman. Although candidiasis is the most common opportunistic fungal infection in humans, C. utilis had not been associated with human morbidity until two cases of fungemia were reported in 1988 and 1993. The clinical features exhibited typical feather-like infiltration at the ulceration margin of this case. After treatment with topical fluconazole and amphotericin-B, the ulceration healed within 3 weeks. The patient underwent penetrating keratoplasty and regained useful vision. We concluded that C. utilis is a new corneal pathogen and should be included in the differential list of mycotic keratitis.

Treatment of Acanthamoeba keratitis combined with fungal infection with polyhexamethylene biguanide.

From July 1996 to March 1997, three cases of Acanthamoeba keratitis combined with fungal infection were diagnosed and treated at our ophthalmic department. Specimens from all of these cases were obtained by corneal scraping, keratectomy and anterior chamber paracentesis. The diagnosis was confirmed by either the results of smear test or pathology reports. All of these patients received aggressive treatment with polyhexamethylene biguanide (PHMB) 0.02%, fluconazole, and anegyn eye drops. After the infection had been controlled without extension, therapeutic penetrating keratoplasty was performed on all of these patients despite the existence of infiltration beyond the edge of the graft. Postoperatively, eye drops were tapered gradually, and treatment was continued for 1 to 2 months. All three cases achieved good results and there was no recurrence of infection. Two cases had visual acuity of 20/100 and 20/20, while the other one perceived hand movement only due to later graft rejection. These cases suggest that early diagnosis and immediate use of PHMB and anti-fungal agents are effective in the treatment of Acanthamoeba keratitis combined with fungal infection.

Capability of neurite regeneration of retinal explant from adult rat after optic nerve injury.

Axons of the central nervous system in adult mammals do not regenerate spontaneously after axotomy. To understand whether the optic nerve of adult mammals loses the intrinsic capability to regenerate after injury, we have studied the capability of neurite regeneration of retinal explant from adult rat after optic nerve axotomy in vitro. After experimental blunt damage to the optic nerve of adult Wistar rat, the retinal explants from three days, one week, two weeks and three weeks after axotomy were put in tissue culture to observe the neurite growth after four days' incubation. The neurites were identified as retinal neuron origin by immunocytochemical staining using monoclonal antibody to neurofilament. The results demonstrate that retinal explants from adult rat after optic nerve damage have the capability of neurite regeneration; the capability is strongest in the group of one week after axotomy of optic nerve, but it decreases with passage of the time. On the other hand, the retinal explant from the control group of uninjured eye does not regenerate neurite in tissue culture. These results indicate that the retinal explant of adult rat has intrinsic capability to regenerate after optic nerve injury in vitro, and the capability of neurite regeneration decreases after one week post-trauma.

Capability of neurite regeneration of rat retinal explant at different ages.

Neurite regeneration from central nervous tissue of mammalian has been demonstrated to occur in early postnatal stage but not in adult stage. To answer when the retinal explant of rat loses the neurite regeneration in vitro after birth, we have used tissue culture to study the neurite regeneration of retinal explant of Wistar rat at different ages. The retinal explants from rat at first postnatal day, 3rd postnatal day, one week, two weeks, three weeks, four weeks old and of the adult were put in tissue culture to observe the neurite growth after four-day incubation. The neurites were also identified by immunochemical staining using monoclonal antibody to neurofilament. The capability of neurite regeneration of retinal explant was decreased with the passage of time after birth, and it was lost after two weeks old. The age of losing retinal regenerative capability coincides with that of eye opening and retinal maturation of Wistar rat (15th-18th postnatal day, mean 16.2 +/- 1.3 days). These results indicate that when the development of retina has been completed, it will lose the capability of regeneration in vitro.

Vanidilol: a vanilloid-type vasorelaxant and ocular hypotensive beta-adrenoceptor blocker with partial beta-2-agonist activity.

Vanidilol, [4'-(2-hydroxy-3-(tert-butylamino)propoxy)-3'-methoxyphenyl] -benzaldehyde, newly synthesized from vanillin, is a vanilloid-type beta-adrenoceptor blocker. The beta-adrenoceptor-blocking properties of vanidilol were studied both in vivo and in vitro. Intravenous injection of vanidilol (1.0, 3.0, 5.0 mg/kg) in anesthetized Wistar rats produced a decrease in blood pressure and a dose-dependent bradycardia response. Vanidilol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by phenylephrine. In isolated guinea-pig tissues, vanidilol attenuated the (-)isoproterenol-induced positive chronotropic and inotropic effects of the atria and trachea relaxation responses in a concentration-dependent manner. The parallel shift to the right of the concentration-response curve of (-)isoproterenol suggested that the agent was a beta-adrenoceptor competitive antagonist. The apparent pA2 values for vanidilol on the right atria, left atria and trachea were 7.67 +/- 0.03, 7.89 +/- 1.02 and 7.66 +/- 0.15, respectively, denoting that vanidilol was a nonselective beta-blocker. The intrinsic sympathomimetic activity of vanidilol and propranolol was determined on isolated atria and trachea from reserpinized guinea pigs. Propranolol caused significantly negative inotropic and chronotropic effects at 10(-6) mol/l or above, whereas vanidilol possessed less cardiodepressant activities than propranolol. In reserpinized tracheal strips, vanidilol produced dose-dependent relaxant responses, but propranolol was ineffective. Preincubating the preparations with ICI 118,551 (0.1-10 nmol/l), a beta 2-adrenoceptor antagonist, significantly shifted the concentration-relaxation curves of vanidilol to a region of higher concentrations. In isolated guinea-pig thoracic aorta, vanidilol (0.1-10 mumol/l) inhibited the phenylephrine (10(-5) mol/l)-induced tonic contraction in vascular smooth muscle which was related to the block of calcium influx. In 20% saline-perfused rabbits, vanidilol showed a marked delay in intraocular pressure recovery, demonstrating an ocular hypotensive action. Binding characteristics of vanidilol and propranolol were evaluated in [3H]dihydroalprenolol binding to porcine ventricular membranes. Vanidilol was less potent than propranolol in competing for the beta-adrenoceptor-binding sites. On the other hand, vanidilol had a high hydrophilicity in comparison with propranolol. In conclusion, vanidilol exhibited nonselective beta-adrenoceptor blocking, vasorelaxant and ocular hypotensive activities, but was devoid of alpha-adrenoceptor blocking and beta 1-agonist activity. Partial beta 2-adrenoceptor agonist activity and inhibitory activity on calcium influx may share in the vasorelaxant activity.

Rapid identification of mycobacteria to the species level by polymerase chain reaction and restriction enzyme analysis--a case report of corneal ulcer.

We report a case of corneal ulcer caused by nontuberculous mycobacteria which was confirmed by smear and culture. We attempted a new method for the rapid identification of mycobacteria to the species level on the basis of evaluation by the polymerase chain reaction of the gene encoding. The method is involved with restriction enzyme analysis of PCR product obtained with primers common to all mycobacteria. Using the restriction enzyme Bst EII and Hae III, clinically relevant and other frequent laboratory isolates were differentiated to the species or subspecies level by PCR-restriction enzyme analysis. The main prevalence of pattern analysis is Mycobacterium chelonae subsp. abscessus in this case. The outcome suggests that PCR-restriction enzyme analysis should be a useful method for early diagnosis concerning nontuberculous mycobacterial keratitis.

A molecular study of ocular herpes simplex infection in Kaohsiung, Taiwan. Part I: Cleavage pattern analysis.

In order to investigate the relationship between genotypes of herpes simplex virus (HSV) and its clinical pictures in herpes simplex virus keratoconjunctivitis (HSK), fifty nine strains of HSV isolates, collected in the Kaohsiung Medical College Hospital during January 1981 to July 1991, and F strain (ATCC VR-73), a standard HSV-1, were studied. The viruses were isolated from HSK patients. All 59 strains were identified as HSV-1 using immunofluorescence monoclonal antibody method. The HSV DNAs were extracted and digested by restriction enzymes, BamH I, Kpn I and Sal I, followed by electrophoresis, and photographing. Six kinds of DNA cleavage patterns were found in Taiwan. The majority were E subtype (56.4%) then A subtype (27.3%), D subtype (7.3%), F subtype (5.4%), G subtype (1.8%) and H subtype (1.8%). Subtypes B and C were not found in this study. The cleavage patterns of two recurrent cases belonged to E and A subtypes. The identical cleavage patterns of two bilateral infections all belonged to the E subtype.

[The re-evaluation of the prevalence of trachoma in primary school children in Kaohsiung City].

For years, trachoma screening has been a routine part of the health examination program for all primary school children. In order to ascertain the current prevalence of trachoma in primary school children, we used clinical examination, immunofluorescein-monoclonal antibody and McCoy cell culture technique to examine 771 children from 5 primary schools in Kaohsiung City. Using the results of the McCoy cell culture as a judgement standard, we found that 118 children (15.3%) had chlamydia trachomatis infections. The infection rates of children were statistically insignificant for sex, grade and location of school of children. Among the 118 infected children, most had none or mild (96.6%) conjunctival inflammation. Only 3 children (0.4%) had conjunctival cicatrization complications. These results showed that the repeated reinfections among these children were quite few. The McCoy cell culture was used to test the result of clinical diagnosis made by the senior ophthalmologists. The sensitivity of the clinical diagnosis was 50% and the predictive positive rate was 26.6%. It revealed that the diagnosis of trachoma made by clinical observation only was unreliable. The results of immunofluorescein-monoclonal antibody test showed that 120 children (15.6%) had trachomatous infections. Its sensitivity was 68.4%, and specificity was 91.7%. It revealed that more care should be taken in quality control of laboratory techniques. From these results, we conclude: 1) the trachomatous infections of primary school children in Kaohsiung City are not serious; the repeated infections among

Vaninolol: a novel compound for the treatment of glaucoma and ischemic retinopathy.

Vaninolol has been confirmed as a selective beta 1-adrenergic blocking agent. The new compound was studied for its effects on intraocular pressure (IOP), the ocular blood flow and the retinal function in this report. Vaninolol showed marked delay in IOP recovery demonstrating that the agent possessed an ocular hypotensive action. This effect is equipotent or slightly more active than L-timolol. In addition, effects of vaninolol on the ocular blood flow of ocular hypertensive eyes were determined using the colored microspheres technique. It was found that vaninolol improved the ocular blood flow in ciliary body and retina, but not in iris and choroid. Further, vaninolol is able to improve the b-wave recovery in electroretinography significantly, indicating that it is possible to develop a new agent for the treatment of ischemic retinopathy.

Seroepidemiological study of coxsackievirus type A24 variant (CA24v) in Taiwan.

In October 1985 and June 1986, for the first time, Taiwan experienced two outbreaks of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v). Sera of virologically and clinically confirmed cases were studied together with the pre- and post-epidemic serum samples by the microneutralization method (cut-off titer, 1:8). The serum samples included 16 cases of virologically confirmed AHC and 18 cases of clinically diagnosed AHC which were collected during the period of January to July, 1987 (i.e., 7 to 21 months after the epidemic). In the same period of time, 374 serum samples were randomly collected as a post-epidemic control group. Meanwhile, 206 serum samples, which were randomly collected in 1980, were studied as a pre-epidemic control group. The results showed that in terms of CA24v neutralizing antibody (NTAb) positivity, a significant difference was found between the pre- and post-epidemic random sample groups (5.3% vs. 28.1%, P < 0.001) while no significant differences among the virologically confirmed, the clinically diagnosed and the post-epidemic random sample groups were noticed (31.3% vs. 28.1%; 44.4% vs. 28.1%, P > 0.05). For comparison, the enterovirus 70 (EV70) NTAb of the samples was studied simultaneously. The results showed that the positive rate and geometric mean titer of CA24v NTAb were lower than those of EV70 even in the post-epidemic serum samples collected shortly after the CA24v epidemic.

Study on some biological and antigenic characteristics of CA24v isolates in Taiwan in 1985-1989.

In order to understand the relationship between the CA24v isolates which caused two epidemics of acute hemorrhagic conjunctivitis (AHC) in 1985-1986 and 1988-1989 in Taiwan, biological and antigenic characteristics were studied with four CA24v strains, L077/85, V116/86, 590/88 and 722/89, which were isolated during the epidemics. The prototype strain, EH24/70, was used for comparison. In terms of cross neutralization, kinetic neutralization, plaque assay and protein electrophoresis, no obvious differences were found between the isolates from the two epidemics though differences were found between these isolates and the prototype.

Mycobacterium smegmatis keratitis after radial keratotomy--a case report.

A 42-year-old woman who developed a corneal ulcer in the left eye after radial keratotomy. The acid-fast stain showed that numerous clusters of acid-fast bacilli and Mycobacterium smegmatis were isolated on the culture. To the best of our knowledge, this is the first documented case of Mycobacterium smegmatis keratitis in the world literature. The sensitivity test showed that this organism resistant to all the anti-tuberculous agents and antibiotics we test. An initial response to amikacin and kanamycin was found, but relapse of infiltrate was noted one month later. The regimen was therefore changed to a combination of amikacin with ofloxacin. This patient had a favorable response to the topical therapy with amikacin and ofloxacin.

Intractable nontuberculous mycobacterial keratitis successfully treated by penetrating keratoplasty--3 cases report.

Since the first diagnosis of nontuberculous mycobacterial keratitis in Taiwan on 1983 by Chen et al., we have collected another 70 cases. Although most of the cases were difficult to treat medically, almost all cases healed before optical penetrating keratoplasties were performed. But, three of these cases responded poorly to medical treatment with sporadical relapse. Finally, penetrating keratoplasties (PKP) were performed on these three cases. These three cases were all males, aged 48, 27, and 35 respectively. The durations from the onset to receiving PK were 10, 4, and 6 months. All had histories of corneal trauma and all cases responded poorly or inconsistently to topical amikacin, erythromycin and antituberculous drugs. Histopathological examination of the diseased corneas in the first chronic case showed granuloma formation in the area of ulcer base. The second case presented lymphocyte clustering in the subepithelial region. The third case, which was operated in a relatively inflamed stage, had lymphocytes infiltrating the whole layer of the cornea. The results of PKP in the three eyes were therapeutically and optically successful, though the second case failed in the first penetrating keratoplasty due to acute tissue failure without recurrent infection. The best corrected visual acuities in the three eyes, postoperatively, were 20/25, 20/40, and 20/100 respectively. With the successful experience of these three cases, we suggest that performing PKP for intractable nontuberculous mycobacterial keratitis at an early stage may reduce the duration of the patients' suffering.