Corneal birefringence changes after laser assisted in situ keratomileusis and their influence on retinal nerve fibre layer thickness measurement by means of scanning laser polarimetry.

AIM: To evaluate changes in corneal polarisation properties and their influence on peripapillary retinal nerve fibre layer (RNFL) thickness measurements after laser assisted in situ keratomileusis (LASIK) by means of scanning laser polarimetry (SLP) with variable corneal polarisation compensator (VCC) in normal white subjects. METHODS: SLP was performed by means of GDx VCC on 32 eyes of 32 normal subjects who underwent LASIK for ametropia correction. Corneal polarisation axis and magnitude and RNFL thickness were measured before and 8 days after LASIK. RNFL thickness data and corneal polarimetric data of one randomly selected eye per subject were analysed by the Wilcoxon signed ranks test. Correlations between corneal ablation depth, corneal polarimetric changes, and RNFL thickness changes were investigated using Spearman's rho test. RESULTS: The corneal polarisation axis significantly shifted from 15.1 degrees (17.0 degrees ) to 6.9 degrees (12.9 degrees ) (p = 0.00006) after LASIK and this change showed a strong correlation with corneal ablation depth (rho = -0.7, p = 0.00002). Among GDx parameters, TSNIT, SUP, and SD showed significant changes after LASIK and for SUP and SD these changes were well correlated with the shift in corneal polarisation axis (rho = 0.54, p = 0.03 and rho = 0.45, p = 0.01, respectively). SUP and SD changes were neutralised after compensating for corneal polarimetric changes but not TSNIT changes. NFI, a discriminating parameter, was found to be affected after LASIK only after compensating for corneal polarimetric changes. CONCLUSIONS: LASIK induces a shift in corneal polarisation axis which is responsible for inaccuracies in RNFL thickness measurements. A customised compensation for corneal polarimetric changes after LASIK allows normalisation of some of the thickness parameters except for TSNIT and NFI.

Pilot study to evaluate the efficacy and safety of pneumatic trabeculoplasty in glaucoma and ocular hypertension.

PURPOSE: Following laser-assisted in situ keratomileusis (LASIK), intraocular pressure (IOP) is measurably lower in a significant number of cases. It has been proposed that the decrease in IOP may be a real event. Prior trials have evaluated pneumatic trabeculoplasty (PNT) in combination with concomitant glaucoma medications. The aim of this study was to determine the efficacy and the safety of PNT alone to lower IOP in patients with primary open angle glaucoma (POAG) or ocular hypertension (OH). METHODS AND RESULTS: A total of 37 subjects with POAG or OH were enrolled in a prospective, open-label, fellow-eye, multicenter trial to determine the IOP lowering effects of PNT. All subjects underwent ophthalmologic examinations and IOP measurements and were washed out from all glaucoma medications prior to the start of the study. The trial was intrapatient controlled for the first 30 days, with one eye receiving PNT at days 0 and 7 and the fellow eye serving as the control. The second eye was treated with PNT at day 30. The patients were followed for 120 days, with the first eye receiving an additional PNT treatment at days 90 and 97. Two analyses-an intent to treat analysis in which the last IOP measurement for patients dropped from the study was carried forward and an analysis including only those patients who completed the trial-were performed. Of the 37 patients enrolled, 27 (73%) completed the study. For the intent to treat analysis the baseline mean IOP was 24.7+/-1.9 mmHg for eye 1 and 23.6+/-2.3 mmHg for eye 2 and the difference was statistically significant (p<0.05). Using this analysis the differences between eye 1 mean IOP at days 1, 7, 14, and 60 and the baseline mean IOP were statistically significant (p<0.05). The differences between eye 2 mean IOP and the baseline mean IOP were statistically significant (p<0.05) at all time points except day 14 and day 30. The greater mean IOP reductions from the baseline mean IOP for eye 1 were at study day 1 (-16,1%), day 14 (-9%), and day 60 (-8.9%). For eye 2 they were at day 60 (-8.7%) and at day 120 (-9.1%). For the analysis that included only those subjects who completed the trial the decrease in eye 1 mean IOP from baseline was statistically significant (p<0.05) at all time points. The decrease in eye 2 mean IOP from baseline was statistically significant at all time points except day 30. Using this analysis the greater mean IOP reductions from the baseline mean IOP for eye 1 were at study day 1 (-19%), day 14 (-15.7%), day 37 (-16.3%), day 60 (-20.0%), day 90 (-18.1%), day 97 (-16.8%), and day 120 (-15.8%). For eye 2 greater mean IOP reductions from baseline mean IOP were seen on day 37 (-13.0%), day 60 (-16.7%), day 90 (-15.5%), day 97 (-14.5%), and day 120 (-7.2%). No statistically significant differences were found in mean IOP reduction between the two eyes treated. A total of 34 patients (92%) showed adverse effects: conjunctival hyperemia in 26 (70.3%) and conjunctival hemorrhage in 14 (37.8%). CONCLUSIONS: This pilot study of PNT showed a potentially good IOP lowering effect on glaucoma and hypertensive patients. Additional studies would help to better define the types of patients who respond to PNT and to identify risk factors that may lead to treatment failure.

Impaired neural conduction in crossed visual pathways in patients with ocular hypertension.

PURPOSE: To evaluate the neural conduction along crossed and uncrossed visual pathways in patients with ocular hypertension (OHT). METHODS: Fifteen patients (mean age 59.1+/-6.8 years) with OHT (IOP>22 mmHg, Humphrey 24-2 with mean deviation [MD]>-2 dB) were enrolled. They were compared to 15 age-matched controls. In OHT patients and control subjects, visual evoked potentials (VEPs) were recorded using full-field checkerboard patterns (the check subtended 15' of visual arc; contrast 80%) reversed at 2 Hz. VEP responses were simultaneously recorded in the homolateral visual cortex (HC) and in the contralateral visual cortex (CC), with respect to the stimulated eye. RESULTS: In OHT patients, VEP P100 implicit times observed in HC and CC were both significantly delayed (analysis of variance, p<0.01) when compared to those of controls, and, in particular, longer in CC than in HC. The interhemispheric differences (ID: P100 implicit time in HC - P100 implicit time in CC) were significantly higher in OHT patients than controls (-3.16+/-1.80 msec and 1.16+/-1.04 msec, respectively, p=0.001). In OHT patients we observed an MD hemifield difference (difference between nasal and temporal MD values) higher than in controls (-0.82+/-0.80 dB and 0.04+/-1.03 dB, respectively, p<0.01) and significantly correlated with the ID (r: 0.836, p<0.001). CONCLUSIONS: The observed asymmetry in the bioelectrical cortical responses and in the visual hemifield parameters suggests that crossed visual pathways could be impaired earlier than uncrossed visual pathways in OHT patients.

Pulsatile ocular blood flow during pregnancy.

PURPOSE: To study pulsatile ocular blood flow (POBF) throughout pregnancy. METHODS: We enrolled twenty-seven healthy women in the first trimester of gestation, only ten of which were followed through the second trimester, and fourteen non pregnant healthy women. In each subject we measured POBF with the POBF pneumotonometer (OBF Ltd. UK), IOP, blood pressure (BP) and heart rate (HR). An unpaired Student t-test was used to compare pregnant women with non-pregnant women, and a two-tailed paired Student t-test was used to compare the same women in the first and second trimester of pregnancy. p <0.05 is considered statistically significant. RESULTS: Results are presented as means +/- SD. In the first trimester of pregnancy the age was 32 +/- 6, POBF 1516.4 +/- 382 ml/min, IOP 13 +/- 3 mmHg, BP 92 +/- 6 mmHg, and HR 86 +/- 14 beats/min. In the second trimester POBF was 1629.11 +/- 352.4 ml/min, intraocular pressure (IOP) 12 +/- 3 mmHg, BP 96 +/- 3 mmHg, and HR 93 +/- 10 beats/min. In the control group the age was 27 +/- 9, POBF 972.23 +/- 329.3 ml/min, BP 88 +/- 4.3 mmHg, and HR 80 +/- 14 beats/min. POBF increases during the first trimester (p = 0.00008). In the second trimester POBF was higher compared to the first trimester (p = 0.0008). Non significant differences were observed for the other parameters. CONCLUSIONS: The POBF increases throughout gestation. During pregnancy there is an increase in estrogen which induces endothelial-dependent vasodilatation in several tissues. The estrogen changes may influence POBF.

Morphological and functional retinal impairment in Alzheimer's disease patients.

OBJECTIVE: Our study aims to assess the optic nerve fiber layer thickness in vivo, the function of the innermost retinal layer and whether a correlation exists between morphological and functional parameters in patients affected by Alzheimer's Disease (AD). METHODS: Seventeen AD patients (mean age 70.37+/-6.1 years, best corrected visual acuity >8/10 with refractive error between +/-3 sf, intra-ocular pressure (IOP)<18 mmHg) were enrolled. They were compared to 14 age-matched controls. Nerve fiber layer (NFL) thickness was measured by optical coherence tomography (OCT). Three different measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and averaged. The data in all quadrants (12 values averaged) were identified as NFL Overall. Retinal function was assessed by pattern electroretinogram (PERG) recordings using high-contrast (80%) checkerboard stimuli subtending 15 min of the visual arc and reversed at the rate of two reversals/s. RESULTS: In AD eyes, there was a significant (P<0.01) reduction in NFL thickness in each quadrant and in the NFL Overall evaluation compared with the values observed in control eyes. PERGs showed a significant (P<0.01) delay in N35, P50 and N95 implicit times, and reduction in N35-P50 and P50-N95 amplitudes. NFL Overall values were significantly correlated (P<0.01) to the PERG P50 and N95 implicit times and P50-N95 amplitude. No correlations (P>0.01) between NFL values and other PERG parameters (N35 implicit time, N35-P50 amplitude) were found. CONCLUSIONS: Our results suggest that in AD patients, there is a reduction of NFL thickness evaluated in vivo by OCT and this morphological abnormality is related to a retinal dysfunction as revealed by abnormal PERG responses.

Correlation between optical coherence tomography, pattern electroretinogram, and visual evoked potentials in open-angle glaucoma patients.

OBJECTIVE: [corrected] To correlate the nerve fiber layer (NFL) thickness and the visual function evaluated by electrophysiologic retinal and cortical responses assessed in open-angle glaucoma (OAG) eyes. DESIGN: Prospective case-control study. PARTICIPANTS: Thirty glaucoma patients (mean age, 47.1 +/- 7.15 years; refractive error range, +/- 2 spherical equivalent) with a mean deviation of computerized static perimetry (24/2 Humphrey, Dublin, CA) from -5 to -28 dB and intraocular pressure less than 21 mmHg on pharmacologic treatment and 14 age-matched control participants. METHODS: Nerve fiber layer thickness was measured by optical coherence tomography. Retinal and visual pathway function was assessed by simultaneously recording pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) using high-contrast (80%) checkerboard stimuli (the single check edges subtend 15 minutes of the visual arc) reversed at the rate of two reversals per second. Linear regression analyses were adopted to establish the correlation between NFL thickness and PERG and VEP parameters. MAIN OUTCOME MEASURES: Nerve fiber layer thickness measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and then averaged (12 values averaged) and identified as NFL overall, whereas the data obtained in the temporal quadrant only (three values averaged) were identified as NFL temporal. PERG P50 implicit time and P50-N95 amplitude and VEP P100 implicit time and N75-P100 amplitude were also measured. RESULTS: In OAG eyes, we found a significant (P < 0.01) reduction in NFL thickness in both NFL overall and NFL temporal evaluations with respect to the values observed in control eyes. PERG and VEP parameters showed a significant (P < 0.01) delay in implicit time and a reduction in peak-to-peak amplitude. In OAG eyes, the NFL overall and NFL temporal values were significantly correlated (P < 0.01) with the PERG P50 implicit time and P50-95 peak-to-peak amplitude. No correlations (P > 0.01) between NFL values and VEP parameters were found. CONCLUSIONS: There is a correlation between PERG changes and NFL thickness, but there is no correlation between VEP changes and NFL thickness in patients affected by OAG.

Comparative acute effects of brimonidine 0.2% versus dorzolamide 2% combined with beta-blockers in glaucoma.

PURPOSE: To assess the acute intraocular hypotensive efficacy of brimonidine tartrate 0.2% (a highly selective alpha2-adrenergic agonist) compared with dorzolamide 2% (a topical carbonic anhydrase inhibitor) as adjunct therapy to topical beta-blockers in patients with primary open-angle glaucoma. METHODS: A randomized cross-over masked study was performed. We enrolled one eye of each of 28 patients who were on different beta-blocker therapy. We measured the intraocular pressure (IOP) 2 h after the beta-blocker instillation; we then randomly administered one of the two drugs and we compiled an IOP diurnal curve. One month later we repeated the same procedures with the second drug. Unpaired Mann-Whitney U-test was used to compare decreases in IOP between the two drugs (P<0.05). RESULTS: Both brimonidine 0.2% and dorzolamide 2% have good ocular hypotensive efficacy, significantly lowering IOP when compared to beta-blocker therapy alone, for the whole diurnal curve. Maximum mean percent IOP decrease from baseline was 22.0+/-15.7% (4.0+/-2.9 mmHg) for dorzolamide 2% 6 h after instillation and 35.5+/-16.4% (7.0+/-4.1 mmHg) for brimonidine 0.2% 8 h after administration of the drug. When we compared the two treatments, brimonidine 0.2% showed a higher hypotensive effect than 2% dorzolamide after 4 h (28.4+/-16.8% vs 17.6 +/-9.3%; P=0.04) and 8 h (35.5+/-16.4% vs 21.6 +/-10.8%; P=0.04). CONCLUSION: This study indicates that 0.2% brimonidine acutely associated with beta-blockers is an interesting new combination treatment useful in the management of glaucoma.

Do sex and hormonal status influence choroidal circulation?

AIMS: To investigate the relation between pulse amplitude (PA), pulsatile ocular blood flow (POBF), and sex and hormonal status. METHODS: Measurements of POBF and PA were obtained by ocular blood flow tonography in 76 healthy subjects: 32 males and 44 females (age range 17-77 years). Females were divided into two age groups: group 1 (premenopausal) 17-42 years, and group 2 (post-menopausal) 55 years old and over. Two groups of age matched males served as controls. RESULTS: Premenopausal females demonstrated a significantly higher rate of POBF and PA than age matched males and post-menopausal females. CONCLUSION: Sex and hormonal status were shown to influence choroidal circulation.

Vernal keratoconjunctivitis revisited: a case series of 195 patients with long-term followup.

OBJECTIVE: This study aimed at revisiting vernal keratoconjunctivitis (VKC) on the basis of anamnestic, clinical, immunologic, histopathologic, and followup data of 195 patients. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: One hundred and ninety-five patients with VKC. METHODS: Clinical evaluation and outcome in 151 of 195 patients with a median followup of 47 months. Evaluation was by telephone survey in 69 patients. MAIN OUTCOME MEASURES: (1) Demographic, clinical, and immunologic features of VKC and their influence on the course of the disease; (2) conjunctival and corneal complications and efficacy of treatment observed during the followup period. RESULTS: VKC is a chronic disease. More than 60% of patients had repeated recurrences all year round. Males had an earlier presentation of symptoms than females and the male/female ratio decreased with age. Major (greater than 80%) and minor (up to 80%) diagnostic criteria were defined for clinical signs and symptoms of the disease. Negative skin test or radioallergosorbent test was present in approximately 50% of patients, whereas eosinophil infiltration was a constant histopathologic finding. A marked conjunctival sensitivity to nonspecific stimuli was noted in more than one third of patients. In 6% of cases, a reduction of visual acuity resulted from corneal scarring, and in 2% of patients, steroid-induced glaucoma was observed. The large size of giant papillae indicates poor prognosis for the persistence of the disease and its evolution into a chronic, perennial condition. CONCLUSIONS: VKC is a chronic eosinophilic disease of the ocular surface involving IgE, non IgE-mediated mechanisms, and age-sex-related influences. Although the disease has a good prognosis, severe visual impairments may result from long-standing inflammation.

Correlation between morphological and functional retinal impairment in multiple sclerosis patients.

PURPOSE: To assess whether a correlation exists between optic nerve fiber layer (NFL) thickness and the retinal or visual pathway function in multiple sclerosis (MS) patients previously affected by optic neuritis. METHODS: Fourteen patients with a diagnosis of definite MS were examined. All had been affected by optic neuritis (MSON) with complete recovery of visual acuity (14 eyes included in study). These were compared with 14 eyes from 14 age-matched control subjects. NFL thickness was measured by optical coherence tomography (OCT). Three different measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and averaged. The data in all quadrants (12 values averaged) were identified as NFL Overall, whereas the data obtained in the temporal quadrant only (3 values averaged) were identified as NFL Temporal. Retinal and visual pathway function was assessed by simultaneously recording pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) using high-contrast (80%) checkerboard stimuli subtending 15 minutes and 60 minutes of the visual arc (min arc) and reversed at the rate of two reversals per second. RESULTS: In MSON eyes there was a significant (P < 0.01) reduction in NFL thickness in both NFL Overall and NFL Temporal evaluations compared with the values observed in control eyes. PERG, (15-min arc checks) and VEP (15-min arc and 60-min arc checks), showed a significant (P < 0.01) delay in latency and reduction in amplitude. NFL Overall and NFL Temporal values were significantly correlated (P < 0.01) to the PERG P50 latency and P50 to N95 amplitude recorded with 15-min arc checks. No correlations (P > 0.01) between NFL values and the other electrophysiological data (PERG recorded with 60-min arc checks and VEP recorded with 15-min arc and 60-min arc checks) were found. CONCLUSIONS: There is a correlation between PERG changes and NFL thickness in MS patients previously affected by optic neuritis, but there is no correlation between VEP changes and NFL thickness.

Topical lomefloxacin 0.3% twice daily versus tobramycin 0.3% in acute bacterial conjunctivitis: A multicenter double-blind phase III study.

AIMS/BACKGROUND: To evaluate in a double-masked comparative, prospective, randomized multicenter trial the efficacy of lomefloxacin 0.3% eye drops twice daily and of tobramycin eye drops 4 times daily in patients with acute bacterial conjunctivitis. METHODS: Ninety-nine subjects were enrolled: 50 were treated with lomefloxacin 0.3% eye drops twice daily and 49 with tobramycin 0.3% eye drops 4 times daily. In all patients, conjunctival swabbing and assessment of objective signs and of subjective symptoms were performed. RESULTS: There was no statistical difference for any individual sign or symptom or for the sum score of either key or other signs and symptoms at any of the examination days. The sum score of both key and other signs and symptoms decreased in both groups at day 3-4 as compared to baseline values (p < 0.0001). The decrease in both these scores continued significantly from day 3-4 to day 7-8 (p < 0.05) and was similar in the two treatment groups (p > 0.4). The lowest resistance rate was seen in lomefloxacin (3.5%) and in neomycin (7.0%), while tobramycin showed resistance in 10 out of 88 resistance strains (11.4%). CONCLUSION: Both lomefloxacin 0.3% twice daily and tobramycin 0.3% administered 4 times daily were well tolerated and showed a high degree of clinical and microbiological efficacy in the treatment of acute bacterial conjunctivitis. Lomefloxacin caused less resistance than other antibiotics evaluated.

Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension.

PURPOSE: To test whether the high variability observed when measuring pattern electroretinogram (PERG), visual evoked potentials (VEP), and spatial contrast sensitivity (SCS) in eyes with ocular hypertension is associated with variation in nerve fiber layer thickness, as measured by optical coherence tomography (OCT). METHODS: The study involved 32 untreated eyes (32 patients; age range, 29-64 years) showing a normal whiteon-white 24/2 Humphrey (San Leandro, CA) perimetry, IOP between 23 and 28 mm Hg, best corrected acuity of 20/20 or better, and none of the following papillary signs on conventional color stereo slides: rim notch(es), peripapillary splinter hemorrhages, or increased vertical-to-horizontal cup-to-disc ratio. On recruitment, each eye underwent SCS testing, OCT, PERG, and VEP recordings. Linear regression (Pearson's test) or Spearman's rank regression was adopted for the analysis of the data. RESULTS: The 95% confidence limits of the electrophysiological data were: PERG P50 latency, 59.3 to 63 msec; PERG P50 to N95 amplitude, 0.74 to 1.15 cmV; VEP P100 latency, 113 to 118 msec; VEP N75 to P100 amplitude, 3.81 to 4.90 micromV. The 360 degrees nerve fiber layer thickness overall (NFLO) ranged between 113 and 169 microm (145+/-16 microm; mean+/-SD) and significantly correlated with PERG P50 to N95 amplitude (r: 0.518; P = 0.002), PERG P50 latency (r: -0.470; P = 0.007), VEP N75 to P100 amplitude (r: 0.460; P = 0.008), VEP P100 latency (r = -0.422; P = 0.016) and SCS at 3 cyc/deg (r: -0.358; P = 0.044). CONCLUSIONS: The variability of PERG, VEP, and SCS testing observed in eyes with ocular hypertension is associated with differences in NFL thickness (the thinner the layer, the worse the visual function).

Cytidine-5'-diphosphocholine (citicoline) improves retinal and cortical responses in patients with glaucoma.

PURPOSE: To evaluate the effects of cytidine-5'-diphosphocholine (citicoline) on retinal function and on cortical responses in patients with glaucoma. DESIGN: Randomized clinical trial. PARTICIPANTS: Forty patients with open-angle glaucoma were randomly divided into two age-matched groups: citicoline group ([GC] n = 25) and placebo group ([GP] n = 15). METHODS: The GC patients were treated with Neuroton (citicoline, 1000 mg/day intramuscularly) for 60 days; GP patients were treated with placebo (physiologic solution with additives) for 60 days. After 120 days of washout (day 180), the GC patients were divided into two age-matched groups: in 10 patients (GC1 group) the washout was prolonged for a further 120 days; in 15 patients (GC2 group) a second 60-day period of citicoline treatment was followed by a second 120-day period of washout. At day 180, the washout was extended for another 180 days in GP patients. In all subjects, retinal and cortical responses were evaluated by simultaneous recordings of visual evoked potentials (VEPs) and pattern-electroretinograms (PERGs) at baseline, after 60 days, and after 180 days. At day 300, VEPs and PERGs were also evaluated in GC1 patients, and at 240 and 360 days in GC2 and GP patients. MAIN OUTCOME MEASURES: Visual evoked potential parameters (P100 latency and N75-P100 amplitude); PERG parameters (P50 latency and P50-N95 amplitude); and intraocular pressure. RESULTS: The GP patients displayed similar VEP and PERG parameters in all examinations performed. In GC patients, the treatment with citicoline induced a significant (P < 0.01) improvement of VEP and PERG parameters, and their values were significantly different (P < 0.01) with respect to those of GP patients (P < 0.01). Visual evoked potentials and PERGs, recorded in GC patients after washout, revealed that although there was a worsening trend, the electrophysiologic improvement was still maintained. After a second period of washout, GC1 patients had VEP and PERG parameters similar (P > 0.05) to baseline ones and to those of GP patients. In GC2 patients, a second period of citicoline treatment induced a further (P < 0.01) improvement of VEP and PERG parameters CONCLUSION: Citicoline may induce an improvement of the retinal and of the visual pathway function in patients with glaucoma.

Intraocular pressure-lowering effects of latanoprost monotherapy versus latanoprost or pilocarpine in combination with timolol: a randomized, observer-masked multicenter study in patients with open-angle glaucoma. Italian Latanoprost Study Group.

PURPOSE: To compare intraocular pressure (IOP) after adding either latanoprost or pilocarpine to timolol treatment or switching to latanoprost monotherapy in glaucomatous eyes in which IOP was inadequately controlled with timolol. METHODS: This 6-month randomized study comprised 148 patients with primary open-angle or pseudoexfoliation glaucoma, which was inadequately controlled with topical beta-adrenergic antagonists. After a 2- to 4-week run-in period with timolol 0.5% twice daily, patients were assigned in randomized fashion to three study groups: one group received add-on therapy of latanoprost 0.005% once daily, the second group received add-on therapy of pilocarpine 2% three times daily, and the third group switched to latanoprost 0.005% once daily. Mean diurnal IOP was measured at baseline and after 3 and 6 months of treatment. RESULTS: At 6 months, 128 patients had completed the study. Diurnal IOP was significantly reduced from baseline in all groups. Adding latanoprost to timolol treatment reduced diurnal IOP by 6.1+/-0.3 mmHg (-28%), adding pilocarpine to timolol treatment reduced diurnal IOP by 4.2+/-0.3 mmHg (-19%), and switching from timolol to latanoprost monotherapy reduced diurnal IOP by 5.5+/-0.3 mmHg (-25%). CONCLUSION: A significantly greater reduction in diurnal IOP was achieved after addition of latanoprost than after addition of pilocarpine in patients in whom IOP was not adequately controlled with timolol alone. Further, the results of this study indicate that a switch to latanoprost monotherapy can be attempted before combination treatment is initiated.

Neural conduction in visual pathways in newly-diagnosed IDDM patients.

OBJECTIVES: Visual evoked potentials (VEPs) show abnormal responses in newly-diagnosed insulin-dependent diabetic (IDDM) patients. Electrophysiological methods allow one to dissect and explore different structures contributing to neural conduction in the visual pathways. The aim of our work was to assess whether the VEP abnormalities are due to impaired function of the retinal layers and/or a delayed conduction in the postretinal visual pathways. METHODS: Simultaneous recordings of VEP and pattern-electroretinogram (PERG) were performed at two intervals (at entry of the study and after 3 months) in 14 newly-diagnosed IDDM patients (age: 24.8+/-6.8 years; duration of disease: 3+/-1.5 months), and in 14 age-matched control subjects. RESULTS: In comparison with control subjects, IDDM patients showed: VEP P100 latencies significantly delayed (P < 0.01), a significant impairment of all PERG parameters (P < 0.01) and retinocortical time (RCT, difference between VEP P100 and PERG P50 latencies) and latency window (LW, difference between VEP N75 and PERG P50 latencies) also significantly increased (P < 0.01). All electrophysiological parameters were not significantly changed when retested after 3 months. No correlations were found between VEP P100 latency, RCT, LW and PERG parameters. CONCLUSIONS: Impaired PERG indicates an involvement of the innermost retinal layers; increased values of RCT and LW represent an index of delayed neural conduction in the postretinal visual pathways. Therefore two sources, one retinal (impaired PERG) and one postretinal (delayed RCT and LW), may independently contribute in to the abnormal responses of VEP observed in newly-diagnosed IDDM patients. Three months of relatively-stable metabolic control have not normalized the VEP and PERG impairment.

Impaired VEP after photostress response in multiple sclerosis patients previously affected by optic neuritis.

The aim of our work was to evaluate if an optic nerve involvement (multiple sclerosis patients previously affected by optic neuritis) may induce any change in visual evoked potential (VEP) after photostress response. VEP in basal conditions and after photostress were assessed in 10 patients with defined multiple sclerosis without a history of optic neuritis (MSWO); in 14 patients with defined multiple sclerosis previously affected by optic neuritis but with complete recovery of the visual acuity (MSON) and in 14 age-matched controls. In order to complete the investigation of the retinal function, Transient Pattern electroretinogram (PERG) and steady-state focal-ERG (counterphased gratings presented at 8 Hz in the macular region) were performed in MSON patients only. In MSWO eyes VEP parameters in basal condition and after photostress did not undergo significant changes compared to controls (ANOVA; P > 0.05). In MSON eyes we observed basal VEP with delayed P100 peak latency and reduced N75-P100 amplitude when compared with the control ones (P < 0.01). In MSON eyes the parameters of VEP after photostress underwent large changes and longer recovery time (RT) than in control and MSWO eyes (P < 0.01). In addition; in MSON eyes we found increased transient PERG P50 latency (P < 0.01) and reduced P50-N95 amplitude (P < 0.01); Focal-ERG (that displays a major component at 16 Hz; 2nd harmonic:2P) with reduced 2P amplitudes and delayed 2P phases (P < 0.01). Our results indicate that patients previously affected by optic neuritis present an abnormal VEP after photostress response and this may be ascribed predominantly to an involvement of the inner retinal layers as indicated by the concomitant impairment of PERG and focal-ERG responses.