Retinal nerve fibre thickness measured with optical coherence tomography accurately detects confirmed glaucomatous damage.

AIM: To assess the accuracy of optical coherence tomography (OCT) in detecting damage to a hemifield, patients with hemifield defects confirmed on both static automated perimetry (SAP) and multifocal visual evoked potentials (mfVEP) were studied. METHODS: Eyes of 40 patients with concomitant SAP and mfVEP glaucomatous loss and 25 controls underwent OCT retinal nerve fibre layer (RNFL), mfVEP and 24-2 SAP tests. For the mfVEP and 24-2 SAP, a hemifield was defined as abnormal based upon cluster criteria. On OCT, a hemifield was considered abnormal if one of the five clock hour sectors (3 and 9 o'clock excluded) was at <1% (red) or two were at <5% (yellow). RESULTS: Seventy seven (43%) of the hemifields were abnormal on both mfVEP and SAP tests. The OCT was abnormal for 73 (95%) of these. Only 1 (1%) of the 100 hemifields of the controls was abnormal on OCT. Sensitivity/specificity (one eye per person) was 95/98%. CONCLUSIONS: The OCT RNFL test accurately detects abnormal hemifields confirmed on both subjective and objective functional tests. Identifying abnormal hemifields with a criterion of 1 red (1%) or 2 yellow (5%) clock hours may prove useful in clinical practice.

Axial length and optic disc size in normal eyes.

AIM: To investigate the relationship between optic disc area and axial length in normal eyes of white and black people. METHODS: Consecutive eligible normal subjects were enrolled. Ocular biometry was obtained using A-scan ultrasonography, and reliable images of the optic disc were obtained using a confocal scanning laser ophthalmoscope. The relationship between optic disc area and axial length was assessed using univariate and multivariate models. RESULTS: 281 eyes of 281 subjects were enrolled. Black subjects (n = 157) had significantly larger discs (mean (SD) disc area, 2.12 (0.5) mm(2)) than white subjects (n = 124; 1.97 (0.6) mm(2); t test, p = 0.02). Optic disc area increased with axial length (Pearson's correlation coefficient, r = 0.13, p<0.035) for the entire study population. Multivariate regression models including race, disc area and axial length showed that a significant but weak linear relationship exists between axial length and disc area (partial correlation coefficient 0.14; p<0.024), and with race and disc area (partial correlation coefficient 0.19; p<0.017) when adjusted for the effects of other terms in the model. CONCLUSION: Increased disc area is associated with longer axial length measurements and African ancestry. This may have implications for pathophysiology and risk assessment of glaucoma.

Structural and functional assessment of the macular region in patients with glaucoma.

PURPOSE: To investigate the correlation of a structural measure of the macular area (optical coherence tomography (OCT)) with two functional measures (10-2 Humphrey visual field (HVF) and multifocal visual evoked potential (mfVEP)) of macular function. METHODS: 55 eyes with open-angle glaucoma were enrolled. The 10-2 HVF was defined as abnormal if clusters of > or =3 points with p<5%, one of which had p<1%, were present. The mfVEP was abnormal if probability plots had > or =2 adjacent points with p<1%, or > or =3 adjacent points with p<5% and at least one of these points with p<1%. Two criteria were used for the macular OCT: (I) > or =2 sectors with p<5% or 1 sector with p<1% and (II) 1 sector with p<5%. RESULTS: 54 of the 55 eyes showed an abnormal 10-2 HVF and 50 had central mfVEP defects. The two OCT criteria resulted in sensitivities of 85% and 91%. When both functional tests showed a defect (in 49 eyes), the OCT was abnormal in 45. For the OCT the outer and inner inferior regions were the most likely to be abnormal, and both functional techniques were most abnormal in the superior hemifield. CONCLUSIONS: Good agreement exists between macular thickness and functional defects in patients with glaucoma. Study of the macular region may provide a quantitative measure for disease staging and monitoring.

Detection of glaucoma using operator-dependent versus operator-independent classification in the Heidelberg retinal tomograph-III.

OBJECTIVE: To compare the abilities of a new Glaucoma Probability Scoring (GPS) system and Moorfields regression analysis (MRA) to differentiate between glaucomatous and normal eyes using Heidelberg retinal tomograph (HRT)-III software and race-specific databases. METHODS: In this prospective study, one eye (refractive error < or =5 D) each of consecutive normal patients and those with glaucoma was enrolled. All patients underwent a full eye examination, standard achromatic perimetry (Swedish Interactive Threshold Algorithm-standard automated perimetry (SITA-SAP), program 24-2) and confocal scanning laser ophthalmoscopy (HRT-II) within 1 month. Normal patients had two normal visual fields in both eyes (pattern standard deviation (PSD) >5% and Glaucoma Hemifield Test within 97% normal limits) and a normal clinical examination. Glaucoma was defined on the basis of SITA-SAP visual field loss (PSD<5% or Glaucoma Hemifield Test outside normal limits) on two consecutive visual fields. HRT-II examinations were exported to the HRT-III software (V.3.0), which uses an enlarged race-specific database, consisting of 733 eyes of white people and 215 eyes of black people. Race-adjusted MRA for the most abnormal sector (operator-dependent contour line placement) was compared with the global race-adjusted GPS (operator independent). MRA sectors outside the 99.9% confidence interval limits (outside normal limits) and GPS > or =0.64 were considered abnormal. RESULTS: 136 normal patients (72 black and 64 white patients) and 84 patients with glaucoma (52 black and 32 white patients) were enrolled (mean age 50.4 (SD 14.4) years). The average visual field mean deviation was (-)0.4 (SD 1.1) db for the normal group and (-)7.3 (SD 6.7) db for the glaucoma group (p<0.001). Mean GPS values were 0.21 (SD 0.23) and 0.73 (SD 0.27) for normal and glaucomatous eyes, respectively (p<0.001). Sensitivity and specificity values were 77.1% and 90.3% for GPS, and 71.4% and 91.9% for MRA, respectively. CONCLUSIONS: In this cohort, GPS software sensitivity and specificity values are similar to those of MRA, which requires placement of an operator-dependent contour line. The development of software to detect glaucoma without a contour line is critical to improving the potential use of HRT as a tool for glaucoma detection and screening.

Primary cataract extraction and intraocular lens implantation in penetrating ocular trauma.

PURPOSE: To analyze the postoperative outcome and complication rate after cataract extraction or lensectomy with primary intraocular lens (IOL) implantation for penetrating traumatic cataract. DESIGN: Retrospective, nonconsecutive, noncomparative case series. METHODS: We retrospectively reviewed the files of 21 patients who were admitted to our departments because of traumatic cataract with corneal or scleral laceration caused by penetrating trauma with or without intraocular foreign body (IOFB) from 1992 through 1997. Lens aspiration or manual extracapsular cataract extraction with primary IOL implantation was performed in all patients. Removal of an IOFB was performed in eight patients. MAIN OUTCOME MEASURES: Final visual acuity and deviation of actual refraction from emmetropia and from expected postoperative refraction. RESULTS: The mean follow-up was 20.4 months. Fourteen eyes (67%) achieved final visual acuity of 20/40 or better, 95% obtained 20/60 or better final visual acuity, and all eyes achieved 20/100 or better final visual acuity. Major causes of limited visual acuity were central corneal scar and central retinal injury. Eleven eyes (57%) experienced secondary cataract and underwent neodymium:yytrium-aluminum-garnet capsulotomy. CONCLUSIONS: Primary implantation of posterior chamber lenses after penetrating ocular trauma is associated with favorable visual outcome and a low rate of postoperative complications.

The reculture technique: individualizing the treatment of Acanthamoeba keratitis.

PURPOSE: To assess the efficacy of three drugs in different concentrations against different strains of Acanthamoeba using the reculture technique. METHODS: Cysts and trophozoites were immersed in five separate solutions. The solutions administered included 0.1% and 0.02% polyhexamethylene biguanide (PHMB), 0.1% and 0.02% chlorhexidine, and propamidine isethionate (Brolene). Readings took place after 1, 5, and 24 hours. The cysts and trophozoites were then recultured for an additional period of 48 hours. An effective drug was defined as a medication that inhibited any growth of trophozoites using the reculture technique. RESULTS: Chlorhexidine at concentrations of 0.1% and 0.02% was the only effective drug against all five strains of Acanthamoeba examined, and no trophozoites were detected on plates immersed with this agent. Only 0.1% chlorhexidine was effective in destroying all cysts in the five strains examined. CONCLUSION: We found that 0.02% chlorhexidine was efficient in irradicating all trophozoites and 0.1% chlorhexidine was effective in eradicating all cysts in the samples we examined. Therefore, it may be possible that 0.02% chlorhexidine is a good initial treatment in amoebic keratitis. Sensitivity testing, then, may be performed using the reculture technique and specification of therapy can be made accordingly.