Improvement of Low Luminance Visual Acuity in Patients with Chronic Central Serous Chorioretinopathy after Half-Dose Verteporfin Photodynamic Therapy.

Patients with central serous chorioretinopathy (CSC) often complain of visual difficulties under low luminance conditions. In this study, we evaluated low luminance visual acuity (LLVA) after half-dose verteporfin photodynamic therapy (hdPDT) in eyes with CSC. The study included eight eyes of eight patients with chronic CSC that underwent hdPDT. The best-corrected visual acuity, LLVA and optical coherence tomography (OCT) findings were evaluated at baseline, and at 1, 3, 6, 9, and 12 months after hdPDT. LLVA was measured at six levels of background luminance. Serous retinal detachment was completely resolved in all eyes. Although the mean LLVA at 1 month did not improve significantly compared to baseline at all luminance levels, significant improvements were observed at 3, 6, 9, and 12 months (p < 0.05). In OCT images, although the ellipsoid zone was not detectable in all eyes before hdPDT, it was observed in 2 eyes at 1 month, in 7 eyes at 3 months, and in all eyes from 6 months. The LLVA and the ellipsoid zone improved similarly with postoperative time courses. In conclusion, hdPDT improves LLVA in eyes with chronic CSC. The recovery of the ellipsoid zone may play a part in improving LLVA after hdPDT.

Effect of Paracentesis on Retinal Function Associated With Changes in Intraocular Pressure Caused by Intravitreal Injections.

Purpose: Intravitreal injections of antivascular endothelial growth factor agents are widely performed, and subsequent intraocular pressure increase may cause retinal nerve fiber damage. This study aimed to determine the effects of paracentesis before intravitreal injection of an antivascular endothelial growth factor on electroretinograms. Methods: This was a retrospective observational study in a university hospital. Twenty-five eyes of 25 patients who underwent intravitreal injections of antivascular endothelial growth factor agents were selected for evaluation. Intraocular pressures and electroretinograms were recorded before surgery (baseline), after anterior chamber paracentesis, and after intravitreal injection. The amplitudes and latencies of the a- and b-waves, photopic negative response, and oscillatory potential were measured. Changes in each component of the electroretinograms, intraocular pressure, and relationships between these two factors were investigated. The preoperative and postoperative ocular perfusion pressure was calculated based on blood pressure. Results: The amplitudes of the b-waves were significantly smaller after intravitreal injection than at baseline (P = 0.02), while no significant change was found in the other components during surgery. There were no significant changes in the latencies of any component during surgery. The intraocular pressure was significantly lower (P < 0.001) after anterior chamber paracentesis (6.8 ± 4.3 mm Hg) compared to baseline (24.1 ± 8.1 mm Hg) or after intravitreal injection (17.1 ± 9.6 mm Hg; P < 0.001). Conclusions: Performing anterior chamber paracentesis before an intravitreal injection can prevent the intraocular pressure elevation and thus minimize the electrophysiological retinal dysfunction. Translational Relevance: Anterior chamber paracentesis before an intravitreal injection mitigates the adverse effects on retinal function.

Heads-Up 3D Surgery under Low Light Intensity Conditions: New High-Sensitivity HD Camera for Ophthalmological Microscopes.

PURPOSE: To determine the feasibility of performing intraocular surgeries in a heads-up position with low illuminance conditions by observing a display of the surgical field created by a three-dimensional imaging (3D) system. METHODS: Seventy-four eyes of 56 patients underwent cataract surgery (72 eyes) with the heads-up 3D surgery system; 60 eyes with cataract surgery alone, 7 eyes with combined cataract and glaucoma microdevice implant surgery, 5 eyes with combined cataract and vitrectomy surgery, and two eyes with vitrectomy surgery alone were studied. The illuminance from the surgical microscope was set to be dimmer (Leica M822F40 main light 2%; otto-flex 6%) than the usual setting to minimize the discomfort and glare for the patient. The surgeries were performed under topical anesthesia. The luminance of the images observed through the eyepieces of the operating microscope and the image of a 3D system created by a high-sensitivity sensor Exmor R 3CMOS HD camera (Sony MCC-1000MD) were measured. RESULTS: All surgeries were completed without any complications under the low illumination conditions. The surgical field on the display monitor was created by a 3D system using a high-sensitivity sensor camera and was observed in a heads-up position. The patients did not report any intolerable discomfort or glare during the surgery. Cataract surgeries were performed with a good view of the surgical field under the extremely low illumination from the surgical microscope. The high-sensitivity sensors and electronic amplifications of the image signals made the surgical field brighter and allowed the surgeon to perform the surgery confidently and safely. CONCLUSIONS: Heads-up, 3D-assisted intraocular surgeries can be performed safely and efficiently with low illuminance of the surgical field. This trial is registered with UMIN000037838.

Retinal function determined by flicker ERGs before and soon after intravitreal injection of anti-VEGF agents.

BACKGROUND: To evaluate the retinal function before and soon after an intravitreal injection of an anti-vascular endothelial growth factor (anti-VEGF) agents. METHODS: Seventy-nine eyes of 79 patients that were treated by an intravitreal injection of an anti-VEGF agent for age-related macular degeneration (AMD), diabetic macular edema (DME), or retinal vein occlusion (RVO) with macular edema (ME) were studied. The RETeval® system was used to record 28 Hz flicker electroretinograms (ERGs) from the injected and non-injected eyes before (Phase 1, P1), within 2 h after the injection (P2), and 2 to 24 h after the injection (P3). Patients were grouped by disease or by the injected agent and compared. The significance of the changes in the implicit times and amplitudes was determined by t tests. RESULTS: The amplitudes were not significantly different at the three phases. The implicit time of the injected eye was 31.2 ± 3.2 msec at P1, and it was not significantly different at P2 (31.7 ± 3.1 msec) but it was significantly longer at P3 (32.2 ± 3.3 msec, P < 0.01, ANOVA for both). The implicit time in the non-injected fellow eye was 30.5 ± 3.3 msec at P1, and it was significantly longer at P2 (31.1 ± 3.2 msec) and phase 3 (31.3 ± 3.4 msec, P < 0.01, ANOVA for both). CONCLUSIONS: The results indicate that an intravitreal anti-VEGF injection will increase the implicit times not only in the injected eye but also in the non-injected eye soon after the intravitreal injection.

Electroretinograms before and after extraction of large intraocular iron foreign body.

PURPOSE: We present our findings in a case with an intraocular foreign body in which the electroretinographic (ERG) findings were useful. OBSERVATIONS: A 37-year-old man was injured by an iron fragment that penetrated into his left eye through the cornea. His visual acuity was counting fingers, and a traumatic cataract prevented an examination of the fundus. B-mode ultrasonography showed a stick-like foreign body of approximately 14 mm in length in the eye. Preoperative ERGs with a contact lens electrode showed reduced responses with many blinking artifacts. Lensectomy and pars plana vitrectomy were performed and a fragment of a wire brush was seen embedded in the superior nasal retina which was removed. The decimal visual acuity improved to 1.2 two weeks later. The postoperative ERG performed with a skin electrode showed reduced responses in the injured eye. CONCLUSIONS AND IMPORTANCE: We recommend that the physiology of the retina be assessed by recording ERGs with a skin-type electrode as soon as possible after a traumatic injury to the eye.

Intraoperative electrophysiological evaluations of macular function during peripheral scleral indentation.

Scleral indentation is widely used to examine the peripheral fundus, however it can increase the intraocular pressure (IOP) to high levels which can then affect retinal function. We evaluated the effects of scleral indentation on the macular function electrophysiologically. Intraoperative focal macular electroretinograms (iFMERGs) were recorded with and without controlling the IOP in 7 eyes. Without IOP control, the IOP increased from 21.7 ± 4.9 to 92.7 ± 20.2 mmHg significantly (P = 0.020) and the amplitudes of the b-wave (from 6.29 ± 1.160 to 3.71 ± 1.98 uV, P = 0.007), on-photopic negative response (from 2.29 ± 0.99 to 0.72 ± 0.47 uV, on-PhNR, P = 0.005), and d-wave (from 2.57 ± 0.41 to 1.64 ± 0.69 uV, P = 0.007) decreased significantly soon after beginning the indentation. All values returned to the baseline levels after releasing the indentation. In the eyes with IOP controlled, the IOP and the amplitude of all components did not change significantly during and after the indentation except the on-PhNR amplitude which was significantly reduced during the indentation. The changes in the iFMERGs and macular function caused by scleral indentation were transient and reversible. The changes can be minimized by controlling the IOP.

Detailed analysis of family with autosomal recessive bestrophinopathy associated with new BEST1 mutation.

PURPOSE: To describe the clinical and genetic findings in a patient with autosomal recessive bestrophinopathy (ARB) and his healthy parents. METHODS: The patient and his healthy non-consanguineous parents underwent detailed ophthalmic evaluations including electro-oculography (EOG), spectral-domain optical coherence tomography (SD-OCT), and fundus autofluorescence (FAF) imaging. Mutation analysis of the BEST1 gene was performed by Sanger sequencing. RESULTS: The FAF images showed multiple spots of increased autofluorescence, and the sites of these spots corresponded to the yellowish deposits detected by ophthalmoscopy. SD-OCT showed cystoid macular changes and a shallow serous macular detachment. The Arden ratio of the EOG was markedly reduced to 1.1 in both eyes. Genetic analysis of the proband detected two sequence variants of the BEST1 gene in the heterozygous state: a novel variant c.717delG, p.V239VfsX2 and an already described c.763C>T, p.R255W variant associated with Best vitelliform macular dystrophy and ARB. The proband's father carried the c.717delG, p.V239VfsX2 variant in the heterozygous state, and the mother carried the c.763C>T, p.R255W variant in the heterozygous state. The parents who were heterozygous for the BEST1 variants had normal visual acuity, EOG, SD-OCT, and FAF images. CONCLUSIONS: In a truncating BEST1 mutation, the phenotype associated with ARB is most likely due to a marked decrease in the expression of BEST1 promoted by the nonsense-mediated decay surveillance mechanism, and it may depend on the position of the premature termination of the codon created.

Assessment of Macular Function during Vitrectomy: New Approach Using Intraoperative Focal Macular Electroretinograms.

PURPOSE: To describe a new technique to record focal macular electroretinograms (FMERGs) during vitrectomy to assess macular function. METHODS: Intraoperative FMERGs (iFMERGs) were recorded in ten patients (10 eyes) who undergo vitrectomy. iFMERGs were elicited by focal macular stimulation. The stimulus light was directed to the macular area through a 25 gauge (25G) glass fiber optic bundle. Background light was delivered through a dual chandelier-type light fiber probe. Focal macular responses elicited with combinations of stimulus and background luminances were analyzed. RESULTS: A stimulus luminance that was approximately 1.75 log units brighter than the background light was able to elicit focal macular responses that were not contaminated by stray light responses. Thus, a stimulus luminance of 160 cd/m2 delivered on a background of 3 cd/m2 elicited iFMEGs from only the stimulated area. This combination of stimulus and background luminances did not elicit a response when the stimulus was projected onto the optic nerve head. The iFMERGs elicited by a 10° stimulus with a duration of 100 ms and an interstimulus interval of 150 ms consisted of an a-, b-, and d-waves, the oscillatory potentials, and the photopic negative response (PhNR). CONCLUSIONS: Focal ERGs with all components can be recorded from the macula and other retinal areas during vitreous surgery. This new technique will allow surgeons to assess the function of focal areas of the retina intraoperatively.

Recovery of photoreceptor inner and outer segment layer thickness after reattachment of rhegmatogenous retinal detachment.

AIMS: To evaluate the recovery of retinal function and the thicknesses of the photoreceptor inner (IS) and outer segment (OS) layers after a reattachment of a rhegmatogenous retinal detachment (RRD). METHODS: 49 eyes of 49 patients (mean age, 57.4±10.3 years) with successfully reattached RRD were retrospectively studied. Spectral-domain optical coherence tomography was used to obtain images of the foveal area, and the thicknesses of the IS and OS were measured before and 1, 3, 6 and 12 months after surgery. The thicknesses of the corresponding structures of the healthy fellow eye served as control. RESULTS: The thickness of the IS layer was 20.4±5.0 µm and that of the OS layer was 34.4±9.7 at 1 month after surgery, which was significantly thinner than the IS (28.9±2.9) and OS (55.4±5.2) layers of the fellow eyes. The thicknesses gradually increased and were not significantly different from that in the fellow eye at 12 months (IS, 28.4±4.4 µm and OS, 50.7±6.6 µm). The IS and OS thicknesses at 1 month after surgery in eyes that had a decimal visual acuity of 1.0 at 6 months were significantly thicker than those in eyes that had a visual acuity of <1.0. CONCLUSIONS: The increase in the thicknesses of the IS and OS layers of the photoreceptors during the recovery phase of eyes with RRD indicates that the recovery process was slow and gradual. Quantitative analysis of the IS and OS thicknesses may be useful to follow the disease process.

One-year outcomes with half-dose verteporfin photodynamic therapy for chronic central serous chorioretinopathy.

PURPOSE: To assess the 1-year outcome of half-dose verteporfin photodynamic therapy (PDT) for patients with chronic central serous chorioretinopathy (CSC). DESIGN: Retrospective, interventional case series with no controls. PARTICIPANTS: A total of 204 eyes of 204 patients with chronic CSC were studied. METHODS: Fluorescein angiography (FA) and indocyanine green angiography (ICGA) were performed before PDT. The best-corrected visual acuities (BCVAs) were measured and optical coherence tomography was performed before and 1, 3, 6, 9, and 12 months after PDT. MAIN OUTCOME MEASURES: The main outcome measures were the resolution of the serous retinal detachment (SRD), changes in BCVA, and ocular and systemic complications at 12 months. RESULTS: A total of 182 of 204 eyes (89.2%) had complete resolution of the SRD at 12 months after the PDT. Eleven eyes (5.4%) had a persistent SRD throughout the follow-up period, and 12 eyes (5.9%) had a recurrence of the SRD after an earlier resolution. One of the 12 eyes had a spontaneous resolution of the SRD 6 months after PDT. The mean±standard deviation BCVA in logarithm of the minimum angle of resolution (logMAR) units significantly improved from 0.11±0.25 before to 0.07±0.23 at 1 month, 0.02±0.23 at 3 months, 0.01±0.23 at 6 months, 0.00±0.24 at 9 months, and -0.01±0.22 at 12 months (P<0.0001). The eyes with an SRD at 12 months were more likely to have an intermediate hyperfluorescence on ICGA (chi-square test, P<0.001) and poorer BCVA before the half-dose PDT (Student t test, P=0.04) than those without SRD at 12 months. None of the patients developed any systemic complications or experienced any severe visual reduction after the half-dose PDT. However, polypoidal lesion appeared in 1 eye 8 months after the PDT. CONCLUSIONS: Half-dose PDT is an effective and safe method to treat eyes with chronic CSC with an SRD. The CSC resolved and the BCVA improved significantly after PDT. Half-dose PDT was less effective for cases without intense hyperpermeability on ICGA and those with lower BCVA before the PDT.

Binocular interaction of visually evoked cortical potentials elicited by dichoptic binocular stimulation.

To analyze the interaction of cortical potentials elicited by dichoptic stimulation of the dominant and fellow eyes at different frequencies, a pair of programmed power supply units were used to drive a light emitting diode (LED) mounted in the right and left eyes of light-proof goggles to elicit the visually evoked cortical responses (VECPs). The right eye was stimulated at 11.5 Hz and the left eye at 11.0 Hz. Then the stimulation was repeated with the frequency of stimulation switched to the other eyes. The stimulus duration was 5 ms. The sampling rate was 1.0 Hz, and the duration of collection was 200 ms. The VECP of each eye was extracted separately. Individual VECPs could be recorded separately after simultaneous dichoptic stimulation of each eye. The amplitudes of the VECPs were not significantly different after stimulating the dominant eye and the fellow eye separately. The implicit times of negative peak (N-2) and the second positive peak (P-2) were shorter after stimulation of the dominant eye than after stimulation of the fellow eye, but the difference was not significant. However, the implicit time of N-2 elicited by stimulating the dominant eye was significantly shorter when the stimulation rate was 11.5 Hz. The VECPs elicited by stimulating the two eyes can be recorded separately by simultaneous dichoptic stimulation. Dichoptic simultaneous stimulation required a shorter time and may be a more sensitive method of analyzing binocular interactions compared to the classic VECPs using monocular stimulation.

Pattern visual evoked potentials elicited by organic electroluminescence screen.

PURPOSE: To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). METHOD: Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). RESULTS: The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT) screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. CONCLUSION: The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

Photoreceptor inner and outer segment layer thickness in multiple evanescent white dot syndrome.

PURPOSE: To evaluate the photoreceptor inner and outer segment layer thickness in eyes with MEWDS. DESIGN: Prospective, non-comparative, observational case series. The follow-up duration was 4 months. METHODS: Four women were diagnosed with unilateral MEWDS. The ages of the patients were 25, 24, 35, and 40 years. The retinal microstructure was assessed by spectral-domain optical coherence tomography (SD-OCT). The thickness of the photoreceptor inner (IS) and outer (OS) segments and sum of them (IS + OS) at the fovea were analyzed. RESULTS: The visual acuity was reduced in three of four eyes at the acute phase. SD-OCT showed that the border of IS and OS (IS/OS) line and the cone outer segment tips (COST) line in the macula area were not detected in all four eyes. The IS + OS thickness was 50.3 ± 5.6 µm and that of the healthy fellow eyes was 73.5 ± 7.0 µm (n = 4 eyes). The thickness of the IS was 27.8 ± 2.6 µm and that of the OS was 45.8 ± 7.3 µm. In all eyes, there was a spontaneous improvement of the visual acuity. SD-OCT showed a recovery of only the IS/OS line in the macular area, but the COST line was not visible in three cases. The mean IS + OS thickness increased to 56.0 ± 7.9 µm (n = 4), IS = 26.0 ± 2.0 µm (n = 3), and OS = 30.1 ± 8.7 µm (n = 3) in the early recovery phase, and to 64.8 ± 9.3 µm (n = 4), IS = 28.5 ± 1.7 µm (n = 4), and OS = 36.3 ± 7.9 µm (n = 4) in the late recovery phase. The mean inner and outer segment thickness remained unchanged in the fellow eyes. CONCLUSION: Eyes with MEWDS have changes in the photoreceptor microstructures. The change in the IS + OS thickness during the natural recovery course might be due to an increase in the OS length.

What monitor can replace the cathode-ray tube for visual stimulation to elicit multifocal electroretinograms?

To compare a conventional cathode-ray tube (CRT) screen to organic light-emitting diode (OLED) and liquid crystal display (LCD) screens as visual stimulators to elicit multifocal electroretinograms (mfERGs), mfERGs were recorded from seven eyes of seven healthy volunteers (21 ± 2 years). The mfERGs elicited by a conventional CRT screen (S710, Compaq Computer Co.) were compared to those elicited by a studio-grade master OLED monitor (PVM-1741, Sony, Japan) and a conventional LCD (S1721, Flexscan, Eizo Nanao Corp., Japan). The luminance changes of each monitor were measured with a photodiode. CRT, OLED, and LCD screens with a frame frequency of 60 Hz were studied. A hexagonal stimulus array with 61 stimulus elements was created on each monitor. The serial white stimuli of the OLED screen at 60 Hz did not fuse, and that of the LCD screens fused. The amplitudes of P1 and P2 of the first-order kernels of the mfERGs were not significantly different from those elicited by the CRT and OLED screens, and the P1 amplitude of the first-order kernel elicited by the LCD stimuli was significantly smaller than that elicited by the CRT in all the groups of the averaged hexagonal elements. The implicit times were approximately 10 ms longer in almost all components elicited by the LCD screen compared to those elicited by the CRT screen. The mfERGs elicited by monitors other than the CRT should be carefully interpreted, especially those elicited by LCD screens. The OLED had good performance, and we conclude that it can replace the CRT as a stimulator for mfERGs; however, a collection of normative data is recommended.

Pars plana vitrectomy combined with focal endolaser photocoagulation for idiopathic macular telangiectasia.

Background. To report the outcome of pars plana vitrectomy (PPV) combined with intraoperative endolaser focal photocoagulation (PC) on eyes with idiopathic macular telangiectasis (MacTel) type 1. Methods. This was a retrospective study of two female patients with MacTel type 1 who were resistant to focal photocoagulation, sub-Tenon triamcinolone injection, and/or antiangiogenic drugs. The best-corrected visual acuity (BCVA) was determined, and fluorescein angiography (FA) and spectral domain optical coherence tomography (SD-OCT) were performed before and after surgery for up to 19 months. Results. After surgery, the BCVA gradually improved from 20/100 to 20/20 at 19 months in Case 1 and from 20/50 to 20/13 at 13 months in Case 2. Fluorescein angiography (FA) showed leakage at the late phase, and OCT showed that the cystoid macular edema was resolved and the fovea was considerably thinner postoperatively. Conclusion. Patients with MacTel type 1 who are refractory to the other types of treatments can benefit from PPV combined with intraoperative endolaser focal PC with functional and morphological improvements.

Effect of intraocular lens diameter implanted in enucleated porcine eye on intraocular pressure induced by scleral depression.

The effect of the diameter of an intraocular lens (IOL) implanted in enucleated porcine eyes on the intraocular pressure induced by scleral depression was investigated. Two IOLs of 6 mm and 7 mm optic diameter were implanted. The intraocular pressure (IOP) was monitored during scleral depression by a transducer placed in the midvitreous through a sclerotomy at 6 o'clock. The area under the curve (AUC) of the IOP changes from the beginning of the indentation to the point when the peripheral retinal surface was observed through the IOL optics was measured. The AUC was significantly larger in eyes with a 6 mm IOL than in eyes with a 7 mm IOL (p < 0.05). The IOP elevation at the endpoint was higher in eyes with the 6 mm IOL than in eyes with the 7 mm IOL. We conclude that the AUC may represent the degree of stress induced by scleral depression. The higher AUC value with the X-60 may be because of the longer distance from the peripheral retina to the edge of the IOL optics.

Comparisons of pattern visually evoked potentials elicited by different response time liquid crystal display screens.

PURPOSE: To evaluate the usefulness of a liquid crystal display (LCD) with higher driving frequency and shorter response time (2 ms) as a visual stimulator to elicit pattern reversal visually evoked potentials (p-VEPs). METHOD: p-VEPs were recorded from 12 eyes of 12 healthy volunteers (28.3 ± 9 years). The p-VEPs elicited by a conventional cathode ray tube (CRT) screen were compared to those elicited by a high-speed LCD screen (2-ms LCD, GD245HQbid, Acer, Taipei, Taiwan). The luminance changes of each monitor were measured with a photodiode. RESULTS: During the reversal phase the luminance of the 2-ms LCD screen with 97% contrast was transiently reduced, which can elicit an electroretinogram (ERG) and therefore a flash VEP. The 2-ms LCD with 81% contrast checkerboard had a minimal luminance reduction during the reversal phase, and therefore no ERGs were elicited. No significant differences in the amplitude of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by a CRT or the 2-ms LCD screens as stimulators. CONCLUSION: The luminance change can elicit flash VEPs, and this artifact can be minimized by using a 2-ms LCD screen with reduced contrast of the checkerboard stimulus.

Quantification of metamorphopsia in chronic central serous chorioretinopathy after half-dose verteporfin photodynamic therapy.

PURPOSE: To determine the degree of metamorphopsia before and 1 year after half-dose verteporfin photodynamic therapy in eyes with chronic central serous chorioretinopathy. METHODS: This was a retrospective, noncomparative, interventional case series. Forty-five eyes of 45 consecutive patients with chronic central serous chorioretinopathy were evaluated. The degree of metamorphopsia was measured with M-CHARTS before and at 1, 3, 6, 9, and 12 months after half-dose verteporfin photodynamic therapy. The best-corrected visual acuity was also measured. RESULTS: Forty of the 45 eyes had a complete resolution of the serous retinal detachment at 1 month, 1 eye at 3 months, and 3 eyes at 6 months. The serous retinal detachment in one eye persisted throughout the follow-up period. The mean horizontal metamorphopsia score improved significantly from 0.61 ± 0.52° at baseline to 0.49 ± 0.56° at 12 months (P = 0.04). The vertical metamorphopsia score improved significantly from 0.52 ± 0.53° at baseline to 0.33 ± 0.46° at 12 months (P = 0.005). CONCLUSION: Half-dose verteporfin photodynamic therapy for chronic central serous chorioretinopathy results in significant improvements of metamorphopsia at 1 year, especially in eyes with good best-corrected visual acuity at the baseline. Half-dose verteporfin photodynamic therapy can be a therapeutic option for patients with good visual acuity who complain of metamorphopsia.

Liquid crystal display screens as stimulators for visually evoked potentials: flash effect due to delay in luminance changes.

PURPOSE: The cathode-ray tube (CRT) screen has recently been replaced by liquid crystal display (LCD) screens as visual stimulators for pattern-reversal visually evoked potentials (p-VEPs). The aim of the study was to evaluate the usefulness of LCD screen to elicit p-VEPs. METHODS: The waveforms of the p-VEPs elicited by a LCD panel were compared with those elicited by a conventional CRT screen. The changes in the luminance of each screen were measured with a photodiode, and the mean luminance change was measured with a luminance meter. VEPs and electroretinograms (ERGs) were also recorded when the monitor was covered by a diffuser. RESULTS: The p-VEPs elicited by the LCD consisted of the N75 and P100 components of the conventional VEPs and had good reproducibility. The average latency of these components was significantly delayed by 9.8 ms for N75 and 10.2 ms for P100, and the N75-P100 amplitude was significantly larger than the conventional p-VEP elicited by the CRT screen. During the reversal phase, especially from black-to-white, the luminance of the LCD screen was transiently reduced, and it elicited a flash VEP and ERG. A reduction in the contrast of the checks minimized the transient change in the luminance, and the VEP waveform was more similar to that elicited by the CRT screen. CONCLUSIONS: The results suggest that when an LCD monitor is used as an alternative visual stimulator to elicit p-VEPs, the delay in the luminance change and the flash effect needs to be taken into account.