The effect of central corneal thickness on estimates of the anterior chamber depth

Background: The slitlamp can be used to estimate the anterior chamber depth (ACD). The length of a slit object is increased until the corneal and iris/lens images appear to just touch. Multiplying the just‐touching‐slit‐length (JTSL) by a conversion factor gives an estimate of the ACD as measured by ultrasonography. The purpose of this study was to determine if central corneal thickness (CCT) affects the accuracy of this technique. Methods: The ACD of 50 subjects was measured by A‐scan ultrasonography and estimated by the slitlamp technique. CCT was measured by ultrasonic pachometry. The refractive error was determined subjectively. Results: The average ultrasonographic ACD for all subjects was 3.32 ± 0.65 mm. The average JTSL was 2.46 ± 0.38 mm. The conversion ratio between the ultrasonographic ACD and the average JTSL was 1.35. The predicted ACD using the regression equation of JTSL on the ultrasound anterior chamber depth (USACD) was 3.32 ± 0.54 mm. The corresponding value using the regression equation of JTSL and CCT on USACD was exactly the same, that is, 3.32 ± 0.54 mm. Conclusion: Incorporation of CCT into a regression equation does not improve the accuracy of the Smith technique.     

Mefenamic acid-induced bilateral transient myopia, secondary angle closure glaucoma and choroidal detachment

Drug-induced secondary angle closure is quite common and in the majority of cases simply stopping the medication leads to rapid reversal of the condition and resolution of glaucoma. We describe here a patient who presented with secondary angle closure glaucoma and myopia following mefenamic acid ingestion which was managed successfully by stopping the medication, symptomatic treatment and reassurance.     

派立明与贝特舒联合应用对降眼压的临床观察

目的评价1.00%派立明(AZOPT)与0.25%贝特舒点眼液每日两次点眼对原发性开角型青光眼、高眼压症及抗青光眼术后高眼压的降眼压效果及安全性。方法31例患者51只眼纳入为期2个月的前瞻性研究。在停用其他抗青光眼药物足够长的时间后测量基础值,用药后每2周复查一次共4次,同时观察眼局部及全身副作用。结果用药前眼压为23.85±1.80 mmHg,4次随访眼压下降均值6.55 mmHg(6.06～7.04),眼压下降率27.50%(26.62～28.59%)。少数病例出现烧灼感、视物模糊、口苦等症状,均为轻度能耐受,对视力、眼底无影响。结论派立明与贝特舒联合用药具有稳定的降眼压效果,具良好耐受性。     

Pattern electroretinogram as a function of spatial frequency in ocular hypertension and early glaucoma

Pattern electroretinograms (PERGs) in response to 8.3 Hz alternating gratings (16.6 rev/sec) of different spatial frequencies were recorded in normal subjects as well as in patients affected by early glaucoma and ocular hypertension. In normal subjects the PERG response is spatially tuned, with a maximum at about 1.5 cycles/deg and attenuation at higher and lower spatial frequencies. In all cases of early glaucoma and in the great majority of cases of ocular hypertension the PERG was reduced, as compared with that of normal subjects, mainly in the medium range of spatial frequencies (at which the PERG has its maximal amplitude).     

Frequency Doubling Technology perimetry and standard automated perimetry in migraine

The literature suggests that visual field defects may be more common in people who experience migraine. The Humphrey frequency doubling (FDT) visual field instrument selectively examines the magnocellular visual pathway, but has not previously been used to investigate visual function in migraine. In a masked controlled study we compared Humphrey FDT and Humphrey Swedish Interactive Threshold Algorithm fields of 25 migraine sufferers with 25 age- and gender-matched controls. Although both mean deviation and pattern standard deviation were a little worse in the migraine group, these differences did not reach statistical significance. There were no inter-eye visual field differences in the migraine group compared with controls. Comparing the mean of all the contrast thresholds in each hemisphere, there were no more inter-hemifield visual field differences in the migraine group compared with controls. There was no significant difference between the migraine and control groups in intra-ocular pressures. The visual field parameters were not correlated with the interval since the last migraine headache, the severity of migraine headache, the duration of migraine headache or the number of migraine headaches per annum. In our data, there was no evidence of visual field deficits, a magnocellular deficit, or indications of glaucomatous pathology.     

Ocular perfusion pressures in different types of glaucoma

Summary It is widely accepted that a disturbed blood supply of the optic disc may cause (in addition with an increased intraocular pressure) optic nerve fibre damage. Therefore we measured ocular perfusion pressures in 79 healthy subjects. In 18 patients with low tension glaucoma, in 27 patients suffering from ocular hypertension and in 49 glaucoma (OAG) patients. For measuring perfusion pressures we used the technique of oculooscillo-dynamography (OODG) as described by Ulrich. Additionally we measured intraocular pressure and systemic blood pressure. In OODG the IOP is simultaneously increased in both eyes by application of a suction cup. After increase of the IOP the negative pressure in the suction cup is slowly and linearly decreased. During this decrease the pulse-depending oscillations of each eye are recorded on a strip-chart-recorder. By means of this method retinal and ciliary perfusion pressures can be separated. As a result we could show that mean arterial blood pressure and systolic retinal perfusion pressure were comparable and not statistically significantly different between the groups examined. The systolic ocular perfusion pressures in patients with low tension glaucoma showed a highly statistically significant reduction compared with the other groups. Between healthy subjects, OAG-patients and patients suffering from ocular hypertension there was no difference in systolic ciliary perfusion pressure detectable.     

Extrapolating global visual field indices from local parameters in the nasal region

The local mean and the average difference of four pairs of test locations within the 26° visual field, situated above and below the horizontal nasal meridian, were used to predict the global field indices MD and CLV of the Gl glaucoma program. Out of 539 examinations (194 eyes suspected of having glaucoma), the local indices NDIFF (describing asymmetrical behavior around the nasal horizontal meridian), ND0 (the mean defect in the nasal region), and the global indices MD and CLV were calculated. Seven hundred fifty-five examinations (446 normal eyes) served as a control group. First and second examinations of 146 glaucoma suspect eyes were used to calculate the retest reliability scores for the indices in question. When analyzing the glaucoma suspects, the local index NDIFF, together with the local mean defect, ND0, yielded highly reliable estimates of the global indices MD and CLV, with a retest correlation r = 0.86 for NDIFF, and r = 0.96 for ND0. The covariance of NDIFF with CLV was r = 0.67, while the co-variance of MD with ND0 was r = 0.95.The ranges of the local indices ND0 and NDIFF were each classified into normal range and range of suspected pathology, in analogy to the normal and pathological ranges of the global field indices. Equivalence of the local indices with the corresponding ranges of MD and CLV was investigated and the results are shown. The establishment of local indices may prove to be a powerful tool in early detection of glaucomatous damage.     

The long-tube single plate Molteno implant for the treatment of recalcitrant glaucoma

One hundred cases of recalcitrant glaucoma were operated with a long tube single-plate Molteno implant (LSMI). At the median follow-up of 15 months an intraocular pressure of 19 mm Hg was obtained in 64 of the 87 eyes (73%) which have a minimum follow-up of 6 months (secondary non-neovascular glaucomas=19; congenital glaucomas=26; secondary neovascular glaucomas=12). The interval probability (percentage±standard error) of obtaining a successful result (IOP19 mmHg) was 79% (±13) at twelve months from surgery, and 53% (±24) at the eighteen month interval. The least favorable results were obtained in the secondary non-neovascular glaucomas. Complications observed included choroidal detachment (24%), tube exposure (4%), tube-endothelium contact (6%), plus band keratopathy, fibrous ingrowth, traction retinal detachment and corneal ulcers.Seventeen cases needed repeate surgery for the management of complications. In order to decrease the post-operative hypotony, we have been using a tourniquet suture around the tube at the time of implantation to occlude it temporarily and limit the outflow.     

MIR204 n.37C>T variant as a cause of chorioretinal dystrophy variably associated with iris coloboma,early-onset cataracts and congenital glaucoma

Four members of a three-generation Czech family with early-onset chorioretinal dystrophy were shown to be heterozygous carriers of the n.37C>T in MIR204. The identification of this previously reported pathogenic variant confirms the existence of a distinct clinical entity caused by a sequence change in MIR204. Chorioretinal dystrophy was variably associated with iris coloboma, congenital glaucoma, and premature cataracts extending the phenotypic range of the condition. In silico analysis of the n.37C>T variant revealed 713 novel targets. Additionally, four family members were shown to be affected by albinism resulting from biallelic pathogenic OCA2 variants. Haplotype analysis excluded relatedness with the original family reported to harbour the n.37C>T variant in MIR204. Identification of a second independent family confirms the existence of a distinct MIR204-associated clinical entity and suggests that the phenotype may also involve congenital glaucoma.     

国产房水引流物置入术治疗难治性青光眼远期疗效观察

１９９３年７月～１９９８年１月为１０３例（１０６只眼）难治性青光眼患者施行国产房水引流物（ＨＡＤ）置入术。术后平均随访３２８月。术后１年时平均眼压２２±１．４ｋＰａ。术后１～５年的手术成功率分别为８３８％,８０４％,７７１％,７１０％及６４３％。术中联合应用丝裂霉素Ｃ的病例,其术后１年时的成功率为８９５％。术后常见的并发症有持续性浅前房,局限性脉络膜脱离及眼压升高等。认为ＨＡＤ可用于治疗难治性青光眼。