3D Da Vinci robotic surgery: is it a risk to the surgeon's eye health?

Da Vinci three-dimensional (3D) system has been increasingly used in customary surgical settings, gaining fundamental relevance for abdominal, urological, and gynecological laparoscopic surgery. The aim of this research is to evaluate the degree of discomfort and potential changes in the binocular vision and ocular motility of surgical operators, who employ 3D vision systems during Da Vinci robotic surgery. Twenty-four surgeons were enrolled in the study, including twelve who typically use the 3D Da Vinci system and twelve who routinely employ 2D system. Routine general ophthalmological and orthoptic examinations were conducted at baseline (T0), the day before surgery, and 30 min after the 3D or 2D surgery (T1). In addition, surgeons were interviewed using a questionnaire of 18 symptoms, with each item containing three questions regarding the frequency, severity, and bothersomeness of the symptoms, in order to evaluate the degree of discomfort. Mean age at evaluation was 45.28 ± 8.71 years (range 33-63 years). Cover test, uncover test, and fusional amplitude showed no statistically significant difference. After surgery, no statistical difference was observed in the Da Vinci group on the TNO stereotest (p > 0.9999). However, the difference in the 2D group resulted statistically significant (p = 0.0156). Comparing participants (p 0.0001) and time (T0-T1; p = 0.0137), the difference between the two groups was statistically significant. Surgeons using 2D systems reported more discomfort than those using 3D systems. The absence of short-term consequences following surgery with the Da Vinci 3D system is a promising conclusion, considering the numerous advantages of this technology. Nonetheless, multicenter investigations and more studies are required to verify and interpret our findings.

NEW ARTIFICIAL INTELLIGENCE ANALYSIS FOR PREDICTION OF LONG-TERM VISUAL IMPROVEMENT AFTER EPIRETINAL MEMBRANE SURGERY.

PURPOSE: To predict improvement of best-corrected visual acuity (BCVA) 1 year after pars plana vitrectomy for epiretinal membrane (ERM) using artificial intelligence methods on optical coherence tomography B-scan images. METHODS: Four hundred and eleven (411) patients with Stage II ERM were divided in a group improvement (IM) (≥15 ETDRS letters of VA recovery) and a group no improvement (N-IM) (<15 letters) according to 1-year VA improvement after 25-G pars plana vitrectomy with internal limiting membrane peeling. Primary outcome was the creation of a deep learning classifier (DLC) based on optical coherence tomography B-scan images for prediction. Secondary outcome was assessment of the influence of various clinical and imaging predictors on BCVA improvement. Inception-ResNet-V2 was trained using standard augmentation techniques. Testing was performed on an external data set. For secondary outcome, B-scan acquisitions were analyzed by graders both before and after fibrillary change processing enhancement. RESULTS: The overall performance of the DLC showed a sensitivity of 87.3% and a specificity of 86.2%. Regression analysis showed a difference in preoperative images prevalence of ectopic inner foveal layer, foveal detachment, ellipsoid zone interruption, cotton wool sign, unprocessed fibrillary changes (odds ratio = 2.75 [confidence interval: 2.49-2.96]), and processed fibrillary changes (odds ratio = 5.42 [confidence interval: 4.81-6.08]), whereas preoperative BCVA and central macular thickness did not differ between groups. CONCLUSION: The DLC showed high performances in predicting 1-year visual outcome in ERM surgery patients. Fibrillary changes should also be considered as relevant predictors.

Spyramicine and Trimethoprim-Sulfamethoxazole Combination to Prevent Mother-To-Fetus Transmission of Toxoplasma gondii Infection in Pregnant Women: A 28-Years Single-center Experience.

BACKGROUND: There is weak evidence on the best treatment of pregnant women with Toxoplasma gondii infection to prevent the vertical transmission to the fetus. METHODS: We conducted a 28-year retrospective study aiming to compare the efficacy of three therapeutic regimens [Spiramicyn alone (Spy) vs. Pyrimethamine-Sulfadiazine (P/S) vs. Spiramicyn with Trimethoprim-Sulfamethoxazole (Spy+TMP-SMX)] for the prevention of mother-to-fetus transmission of T. gondii infection. RESULTS: 170 women were included: 58 (34.1%) had certain congenital toxoplasmosis (CT), 61 (35.9%) a probable infection and 41 (24.1%) possible infection. In total 97 mothers (57.1%) were treated with the Spy+TMP-SMX combination, 64 mothers (37.6%) were treated with Spy only and 8 mothers (4.7%) with P/S. Infected infants were 20/170 (11.7%). However, 8.2% (8/97) of infants born to mothers treated with Spy+TMP-SMX were infected, 20% (11/55) of infants born to women treated with Spy and 12.5% (1/8) of infants born to mothers treated with P/S were infected. Logistic regression analysis demonstrated that Spy treatment alone was associated with an increased risk of CT compared to the Spy+TMP-SMX combination (OR, 2.78, 95% CI 1.04-7.41, P value 0.041). No difference was observed when the Spy+TMP-SMX was compared with the P/S combination (OR 1.59; 95% CI 0.17 - 14.58; P value 0.682). Results were confirmed when the analyses were corrected by trimester of infection and by type of maternal treatment (OR 7.72; 95% CI 3.40-17.53, P value <0.001). CONCLUSIONS: The combination of Spy+TMP-SMX may be more effective in reducing the risk of maternal-fetal transmission of Toxoplasmosis compared to Spy alone; furthermore, this combination is not inferior to P/S, the current international standard-of-care maternal treatment for the prevention of CT. A prospective trial comparing the combination Spy+TMP-SMX with P/S would be necessary to provide definitive evidence on the best regimen for pregnant women with T. gondii infection.

Familial Exudative Vitreoretinopathy With Neurodevelopmental Delay and Hypoplasia of the Corpus Callosum.

A 2-year-old child was referred to the authors' pediatric retina service for bilateral retinal folds, strabismus, and psychomotor retardation, as well as marked thinning of the corpus callosum. Family history was unremarkable and genetic testing revealed a previously undescribed mutation in the LRP5 gene. Widefield fundus photography, fluorescein angiography, and spectral-domain optical coherence tomography were used to image the retinal fundus. The authors' case suggests a correlation between LRP5 and neurological development, since its variants may lead to a syndromic condition characterized by FEVR-like abnormalities along with neurodevelopmental delay and hypoplasia of the corpus callosum. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:588-591.].

Long-Term Clinical, Audiological, Visual, Neurocognitive and Behavioral Outcome in Children With Symptomatic and Asymptomatic Congenital Cytomegalovirus Infection Treated With Valganciclovir.

Cytomegalovirus (CMV) is the most common cause of congenital infection in humans. There are no enough data on long-term outcome of newborns with congenital CMV (cCMV) infection, particularly for those asymptomatic at birth. For this reason, we performed this study to evaluate long-term audiological, visual, neurocognitive, and behavioral outcome in patients with symptomatic and asymptomatic cCMV infection treated with oral Valganciclovir (VGC). Thirty-six newborns with confirmed cCMV infection were evaluated: 12 (33.3%) symptomatic at birth and 24 asymptomatic (66.7%). No one had cognitive impairment. Cognitive assessment scales resulted abnormal in 4/35 patients (11.4%). 11/21 patients (52.4%) achieved abnormal scores in neuropsychological tests. The language evaluation gave pathological results in 6/21 (28.5%) patients. 6/35 patients (17.1%) developed SNHL, all symptomatic at birth except one. None of the 34 patients evaluated developed CMV retinopathy. Our study shows that both symptomatic and asymptomatic newborns with cCMV infection develop long-term sequelae, particularly in the behavioral and communicative areas, independently from the trimester of maternal infection.

Early visual and neuro-development in preterm infants with and without retinopathy.

BACKGROUND: Retinopathy of prematurity (ROP) is often associated with visual impairment and multiple developmental disabilities. AIMS: As most of the previous studies include infants with brain lesions, that can determine visual impairment per se, a cohort of low neurological risk preterm infants without ROP and with various degree of severity of ROP was assessed in order to establish visual and neurodevelopmental outcome. STUDY DESIGN: Preterm infants born at <31 weeks gestation, without major brain lesions, underwent visual function assessment at 1 year corrected age and neurodevelopmental assessment at 2 years corrected age. SUBJECTS: One hundred and five infants were included in the study: 42 infants did not develop ROP, 7 reached stage 1 in zone 2 ROP, 37 reached prethreshold (untreated) type 2 ROP. The remaining 19 infants were classified as type 1 ROP. OUTCOME MEASURES: Visual function (including fixing, tracking, visual acuity, visual field, attention at distance and nystagmus) were assessed at 12 months corrected age and Griffiths Scales at 2 years corrected age. RESULTS: The severity of ROP was strongly correlated (p < 0.001) with both visual function at 1 year and neurodevelopment at 2 years. Similarly, the presence of nystagmus was also strongly correlated with visual and neurodevelopmental sequelae. CONCLUSIONS: Infants with no or milder retinopathy showed normal visual function at 1 year and neurodevelopment at 2 years. Infants who underwent treatment more frequently showed abnormal results on several aspects of visual function. Presence of nystagmus appeared to increase the risk for abnormal visual function and neurodevelopmental outcome.

Follow-up to Age 4 Years of Treatment of Type 1 Retinopathy of Prematurity Intravitreal Bevacizumab Injection versus Laser: Fluorescein Angiographic Findings.

PURPOSE: To compare structural outcome at age 4 years of eyes treated with intravitreal injection of bevacizumab with fellow eyes treated with conventional laser photoablation in type 1 retinopathy of prematurity (ROP). DESIGN: Single, randomized, controlled trial. PARTICIPANTS: All inborn babies with type 1 zone 1 ROP at the Neonatal Intensive Care Unit of the Catholic University, Rome, from September 1, 2009, to March 31, 2012. METHODS: In 21 infants (42 eyes), 1 eye was randomized to receive an intravitreal injection of 0.5 mg bevacizumab; the fellow eye underwent conventional laser photoablation. Digital retinal imaging and fluorescein angiography (FA) were performed at an average of 4 years after treatment in follow-up after these studies performed at treatment and 9 months. MAIN OUTCOME MEASURES: Fluorescein angiograms were examined by 2 experts to document retinal and choroidal findings. RESULTS: Among the 20 bevacizumab-treated eyes available at 4 years of age, all showed abnormalities at the periphery (avascular area, vessel leakage, shunts, abnormal vessel branching, and tangles) or the posterior pole (hyperfluorescent lesions, absence of foveal avascular zone). These lesions were not observed in the majority of the lasered eyes. Among the 19 laser-treated eyes, leakage was noted in 1 eye, shunts and tangles were noted in 3 eyes, and macular abnormalities were noted in 3 eyes. CONCLUSIONS: Fluorescein angiography has shown potentially serious and long-term ocular effects that are present more commonly after treatment with bevacizumab for acute-phase ROP than after laser.

Intravitreal bevacizumab versus laser treatment in type 1 retinopathy of prematurity: report on fluorescein angiographic findings.

PURPOSE: To compare the structural outcome at 9 months of eyes treated with intravitreal injection of bevacizumab with fellow eyes treated with conventional laser photoablation in zone I type 1 retinopathy of prematurity (ROP). DESIGN: Single randomized controlled trial. PARTICIPANTS: All inborn babies with type 1 zone I ROP at a single institution were included in the study. One eye was randomized to receive an intravitreal injection of 0.5 mg bevacizumab; the fellow eye received conventional laser photoablation. METHODS: Digital fundus photographs and fluorescein angiography (FA) using the RetCam (Clarity Medical Systems Inc., Pleasanton, CA) were performed before treatment and 9 months after treatment. MAIN OUTCOME MEASURES: Presence of retinal and choroidal abnormalities on FA at 9 months. RESULTS: Thirteen infants were enrolled; 1 died 3 months after birth. One laser-treated eye progressed to stage 5 retinal detachment. The remaining 23 eyes had favorable structural results at the 9-month follow-up and provided FA results. At 9 months of age, all eyes treated with a bevacizumab injection were noted to have abnormalities at the periphery (large avascular area, abnormal branching, shunt) or the posterior pole (hyperfluorescent lesion, absence of foveal avascular zone). These posterior and peripheral lesions were not observed in the majority of the lasered eyes. CONCLUSIONS: This study documents significant vascular and macular abnormalities of eyes in the bevacizumab group. Long-lasting implications of these abnormalities for visual function of the child need to be studied.

Phenylephrine eye drops in pediatric patients undergoing ophthalmic surgery: incidence, presentation, and management of complications during general anesthesia.

BACKGROUND: Phenylephrine eye drops are widely used as mydriatic agent to reach the posterior segment of the eye. In literature, many reports suggest a systemic absorption of this agent as a source of severe adverse drug reactions. Hence, we reviewed our experience with topical phenylephrine in ophthalmic surgery. METHODS: In May 2006, following US guidelines publication, a standard operating procedure was issued in our operating rooms to standardize the use of phenylephrine eye drops in our practice. Two years later, after the occurrence of a cluster of serious adverse drug reactions in infants undergoing surgery, a review of phenylephrine safety and systemic complications incidence was performed. RESULTS: We observed 451 pediatric patients, and 187 met the inclusions criteria: Among them, 4 experienced hemodynamic complications due to phenylephrine eye drops. The incidence of major complications was 2.1%. CONCLUSIONS: Two different patterns of side effects occurred. The first one was a cardiovascular derangement with severe hypertension and heart rate alterations; the other one involved exclusively pulmonary circuit causing early edema. These clinical manifestations, their duration, and treatment responses are all explainable by alfa1-adrenergic action of phenylephrine. This hypothetic pathogenesis has been confirmed also by the usefulness of direct vasodilators (anesthetic agents) and by the negative outcome occurred in the past with the use of beta-blockers.

Fluorescein angiography and retinal vascular development in premature infants.

OBJECTIVE: To investigate the role of fluorescein angiography (FA) in the management of retinopathy of prematurity (ROP) in preterm newborns. METHODS: An observational case series of 13 extremely low birth weight infants. From September 2009 to March 2010, 13 newborn infants with a gestational age <29 weeks end/or birth weight <1000 g underwent serial fluorescein angiography with RetCam (Clarity, Pleasanton, CA) every 2 weeks. The fluorescein angiograms were examined to optimize the timing of diagnosis of ROP and to investigate development of retinal and choroidal vascularization. RESULTS: There were no side effects related to FA. Variable features of retinal and choroidal circulation in preterm infants with a high risk of developing ROP were noted. FA allows vessels branching at the junction between vascular and avascular retina (V-Av junction) to be viewed easily and shows the ROP findings that sometimes cannot be seen by indirect ophthalmoscopy. Dye leakage is the most significant sign of progression to severe ROP or the need for surgery in newborn babies with ROP. CONCLUSIONS: RetCam-assisted intravenous FA is safe and allows a more objective assessment of the ROP stage and zone.

Analysis of risk factors for progression to treatment-requiring ROP in a single neonatal intensive care unit: is the exposure time relevant?

OBJECTIVE: Retinopathy of prematurity (ROP) is a multifactorial disease whose pathogenesis is organized in two phases. We hypothesized that postnatal risk factors may differently exert their effect in a phase dependent way. METHODS: Data obtained from medical records of 93 very low birth weight neonates with stage ≥ 3 ROP were analyzed. Perinatal ROP risk factors were compared between infants with stage 3 ROP not requiring surgery and infants with treatment-requiring ROP with relation to newborn's lifetime exposure. RESULTS: In the first two weeks and in the whole first month of life length of oxygen administration was an independent risk factor for treatment-requiring ROP. In the first month of life also sepsis was identified as independent risk factor for surgical ROP. Sepsis and Candida pneumonia in the time frame from birth to ROP diagnosis and prolonged mechanical ventilation from diagnosis to prethreshold ROP were associated to treatment-requiring ROP. Blood transfusions are the only risk factor for treatment-requiring ROP identified in all the periods analyzed. CONCLUSION: Risk factors for ROP play their role since birth. Beside scrupulous oxygen-administration monitoring and prevention of infections, blood transfusions are of primary importance in the development of treatment-requiring ROP.

Atlas of fluorescein angiographic findings in eyes undergoing laser for retinopathy of prematurity.

PURPOSE: We sought to examine the clinical features of severe retinopathy of prematurity (ROP) using fluorescein angiography (FA). DESIGN: Retrospective case series of eyes with severe acute-phase ROP that underwent FA at the time of laser photocoagulation. PARTICIPANTS: We included 22 eyes of 11 infants that developed ROP stage 3 in zone 1 with plus disease, 8 eyes of 4 infants classified as ROP stage 3 in zone 1 without plus disease, and 21 eyes of 11 infants that developed ROP stage 3 in zone 2 with plus disease. All eyes underwent laser photocoagulation. A total of 51 sets of digital images including FA were obtained immediately before treatment. METHODS: RetCam (Clarity, Pleasanton, CA) fundus images and video digital FAs were performed under general anesthesia right before laser treatment. A 10% solution of fluorescein was intravenously administered as a bolus at a dose of 0.1 ml/kg, followed by an isotonic saline flush. MAIN OUTCOMES MEASURES: Fluorescein angiograms were examined retrospectively to catalog different retinal and choroidal findings RESULTS: In eyes with severe ROP, FA clearly shows extreme variability in both retinal circulation and choroidal filling pattern. Different patterns of vessels branching at the junction between vascular and avascular retina (V-Av junction) are noted. Posterior to the V-Av junction, hypoperfused retinal areas with or without hyperfluorescent "cotton-wool-like" or "popcorn-like" lesions due to dye leakage are documented by FA. Focal dilatation of capillaries, capillary tufts formations, and rosary-bead-like hyperfluorescent lesions inside the vessels were seen; sometimes all 3 are noted. Various macular abnormalities are noted including absence of foveal avascular area and significant exudative component. CONCLUSIONS: Fluorescein angiography was useful to distinguish the deceptively featureless zone 1 junction between the vascularized and nonvascularized retina. Further studies are needed to understand the role of vascular abnormalities observed in zone 1 vascularized retina.

Effectiveness of ketorolac tromethamine in prevention of severe retinopathy of prematurity.

PURPOSE: This study assessed the effectiveness of the use of ketorolac tromethamine to reduce retinopathy of prematurity (ROP) incidence and its progression to more severe forms. METHODS: Forty-seven preterm newborn infants with a birth weight (BW) of 1,000 grams or less and/or a gestational age (GA) of 29 weeks or less were enrolled in the study when avascular retina zone I or ROP any stage were diagnosed at screening. Studied infants were randomized to receive ketorolac tromethamine ophthalmic solution in one eye and a drop of placebo in the other eye, until ROP requiring treatment or full retinal vascularization was diagnosed. RESULTS: Only 2 newborn infants did not develop ROP. Among 45 newborn infants who developed ROP, 6 showed different ROP staging between the two eyes, 4 of which had a better outcome in the eye receiving ketorolac tromethamine. The differences between ROP stagings were not significant even when analyzed by GA and BW subgroups. No significant treatment-related side effects occurred. CONCLUSION: This report suggests that ketorolac tromethamine ophthalmic solution cannot reduce the risk of developing severe ROP in preterm infants.

Cortical visual function in preterm infants in the first year.

OBJECTIVE: To assess visual function in low-risk preterm infants at 3, 5, and 12 months corrected age to determine whether the maturation of visual function in the first year is similar to that reported in term-born infants. STUDY DESIGN: Seventy-five low-risk infants (25.0-30.9 weeks gestation) underwent ophthalmological examinations and a battery of tests (fix and follow, visual fields, acuity, attention at distance, and fixation shift) designed to assess various aspects of visual function at 3, 5, and 12 months corrected age. RESULTS: The results were comparable with normative data from term-born infants in all tests but fixation shift, suggesting that maturation of most aspects of visual function is not significantly affected by preterm birth. In contrast, >25% of preterm infants failed the fixation shift test at 3 months, with a higher percentage of failing at 5 and 12 months. CONCLUSIONS: There is a specific profile of early visual behavior in low-risk preterm infants, with a high percentage of infants failing a test that specifically assesses visual attention and provides a measure of cortical processing.

Visual function at 35 and 40 weeks' postmenstrual age in low-risk preterm infants.

OBJECTIVES: The objectives of this study were to (1) assess visual function in low-risk preterm infants at 35 and 40 weeks' postmenstrual age, (2) compare preterm visual abilities at term-equivalent age with term-born infants, and (3) evaluate effects of preterm extrauterine life on early visual function. METHODS: Visual function was assessed by using a validated test battery at 35 and 40 weeks' postmenstrual age in 109 low-risk preterm infants who were born at <31 weeks' gestation. The preterm findings were compared with data from term-born infants collected by using the same test protocol. RESULTS: All preterm infants completed both assessments. The 35-week responses were generally less mature than those at 40 weeks. Preterm infants at both ages were significantly more mature than term-born infants for ocular movements and vertical and arc tracking and at 40 weeks for stripe discrimination. In contrast, tracking a colored stimulus, attention at distance, and stripe discrimination were more mature at term age (in both term-born and preterm infants) than at 35 weeks. CONCLUSIONS: Our findings provide data for visual function at 35 and 40 weeks' postmenstrual age in low-risk preterm infants. The results suggest that early extrauterine experience may accelerate the maturation of aspects of visual function related to ocular stability and tracking but does not seem to affect other aspects that may be more cortically mediated.

An epidemiological analysis of retinopathy of prematurity over 10 years.

PURPOSE: To analyze the incidence of retinopathy of prematurity (ROP) in a single neonatal intensive care unit over 10 years to clarify its ROP profile and how it was modified by advances in neonatal care. METHODS: Epidemiological data related to incidence and severity of ROP were collected over 10 years. Premature infants with a birth weight of less than 1,500 g underwent a screening fundus examination and ROP was defined according to the International Classification of Retinopathy of Prematurity. The survival rates and incidence of ROP were calculated and compared for two consecutive time periods (1995-1999 vs 2000-2004), dividing the study population into subgroups according to their birth weights and gestational age. RESULTS: Data of 607 preterm infants were collected. Survival rate significantly improved in the later time period (from 76.6% to 88.6%). The incidence of total, severe, and surgical ROP did not differ overall in the two time periods despite changes in survival rate, although some changes occurred in the most immature infants over time. CONCLUSION: Increased survival of immature infants seemed to correlate with an increased risk for severe ROP and need for retinal ablation therapy, even if the incidence did not reach statistical significance.

Regional assessment of cone system function following uncomplicated retinal detachment surgery.

PURPOSE: To evaluate regional cone system function after uncomplicated retinal detachment (RD) surgery, by recording focal electroretinograms (FERGs) from the central and paracentral regions of the posterior pole. METHODS: FERGs in response to either a central (eccentricity: 0-2.25 deg) or a paracentral annular (2.25-9 deg) uniform field, presented on a light adapting background and sinusoidally flickered at 41 Hz (95% modulation depth, 93 cd/m(2) mean luminance) were recorded from 16 eyes (16 patients) 2 weeks to 420 months following uncomplicated RD surgery (encircling procedure with or without scleral buckling). Pre-operatively, 10 out of 16 eyes had a macular RD. Mean time elapsed from onset of symptoms to surgery was 20 days (range: 5-90 days). Post-operatively, visual acuity ranged 0.1 to 1.0. Eight age-matched normal subjects served as controls. Amplitude and phase of the FERG fundamental harmonic were measured. RESULTS: Compared to control eyes, affected eyes' central and paracentral FERGs were on average reduced in amplitude (by 40% and 28%, respectively, p<0.01) and delayed in phase (by 70 and 100 degrees, respectively, p<0.01). Eyes with a macular RD did not differ in FERG amplitude or phase from eyes that had a peripheral RD. In individual affected eyes, central, but not paracentral FERG amplitudes were negatively correlated (p=0.05) with time elapsed from onset of symptoms to surgery. CONCLUSIONS: Central and paracentral cone system dysfunction may be detected even at lengthy time intervals from retinal reattachment, independent of the presence of a pre-operative macular RD. The extent of central loss appears to be inversely related to RD duration, in agreement with previous reflectometric findings on foveal cone photopigment density [Liem et al., 1994; Ophthalmology 10: 1945-51].

Monitoring retinal function during transpupillary thermotherapy for occult choroidal neovascularization in age-related macular degeneration.

PURPOSE: To use focal electroretinography to evaluate changes in retinal function during transpupillary thermotherapy (TTT) for neovascular age-related macular degeneration (ARMD). METHODS: Sixteen eyes of 16 patients with ARMD with occult choroidal neovascularization (CNV) were studied. A 630-nm photocoagulator aiming beam was modified for use as a 41-Hz square-wave focal electroretinogram (fERG) stimulus. The stimulus was presented on a light-adapting background by a Goldmann-type lens (visual angle, 18 degrees; mean luminance, 50 cd/m(2)). fERGs were continuously monitored before, during, and after TTT for occult CNV. The amplitude and phase of the fERG's fundamental harmonic were measured. RESULTS: No suprathreshold or adverse clinical events occurred during the course of the study. fERG amplitude decreased transiently during TTT (23% +/- 9% [SE]; P < 0.05). The decrease in amplitude was greatest 16 to 20 seconds and 32 to 40 seconds after the onset of TTT. It was followed by a recovery to baseline amplitude during TTT (48 to 60 seconds after TTT was begun). Within 60 seconds after TTT was completed, fERG amplitude was within the range of baseline. TTT did not alter the fERG phase. Mean fERG amplitudes and phases recorded 1 week and 1 month after TTT were comparable to mean pretreatment levels. CONCLUSIONS: fERG amplitude decreases transiently during TTT, despite the absence of ophthalmoscopically apparent lesions. Intraoperative amplitude depression may result from an adaptation effect to laser light energy and/or hyperthermia, resulting in desensitization of cone photoreceptors and bipolar cells. Treatment sites are electrophysiologically functional 1 month after TTT. Detailed parametric study of a larger patient group is needed to determine whether fERG testing is potentially useful for monitoring and perhaps for controlling and optimizing TTT for choroidal neovascularization.