Peripapillary vessel density changes in Leber's hereditary optic neuropathy: a new biomarker.

IMPORTANCE: The contribution of the microvascular supply to the pathogenesis of Leber's hereditary optic neuropathy (LHON) is poorly understood. BACKGROUND: We aimed at measuring the peripapillary capillary vessel density (VD) using optical coherence tomography angiography (OCT-A) at different stages of LHON. DESIGN: Prospective, cross-sectional, multicenter, observational study. PARTICIPANTS: Twenty-two LHON patients divided in four groups: unaffected mutation carriers (LHON-u); early sub-acute stage (LHON-e); late sub-acute stage (LHON-l); chronic stage (LHON-ch). METHODS: OCT-A scans centred on the optic disc were obtained by spectral domain OCT system. MAIN OUTCOME MEASURES: VD, retinal nerve fibre layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness were compared between groups. RESULTS: Significant VD changes were detected in every sector (P < 0.0001). In LHON-e, the VD was reduced in the temporal sector compared with LHON-u and in the temporal and inferotemporal sectors compared with controls. In LHON-l, VD was reduced in whole, temporal, superotemporal and inferotemporal sectors compared with LHON-u and controls. In LHON-ch, the VD was reduced in all sectors compared to the other groups. An asynchronous pattern emerged in the temporal sector with VD changes occurring earlier than RNFL thickness changes and together with GC-IPL thinning. CONCLUSIONS AND RELEVANCE: Significant peripapillary miscrovascular changes were detected over the different stages of LHON. Studying the vascular network separately from fibres revealed that microvascular changes in the temporal sector preceded the changes of RNFL and mirrored the GC-IPL changes. Measurements of the peripapillary vascular network may become a useful biomarker to monitor the disease process, evaluate therapeutic efficacy and elucidate pathophysiology.

Optical coherence tomography angiography in acute arteritic and non-arteritic anterior ischemic optic neuropathy.

PURPOSE: The purpose of our study was to describe the feature of acute non-arteritic or arteritic anterior ischemic optic neuropathy (NA-AION and A-AION) using optical coherence tomography angiography (OCT-A) and to compare it with fluorescein angiography (FA) and indocyanine green angiography (ICGA). METHODS: In this retrospective, observational case-control study four NA-AION patients and one A-AION patient were examined by FA, ICGA and OCT-A within 2 weeks from disease presentation. The characteristics of the images were analyzed. Optic nerve head (ONH) and radial peripapillary capillaries (RPC) vessel densities (VDs) were compared between NA-AION and controls. RESULTS: In two of four NA-AION cases and in the A-AION patient, OCT-A clearly identified the boundary of the ischemic area at the level of the optic nerve head, which was comparable to optic disc filling defects detected by FA. In the other two NA-AION cases, a generalized leakage from the disc was visible with FA, yet OCT-A still demonstrated sectorial peripapillary capillary network reduction. Both ONH and RPC VDs were reduced in NA-AION patients, when compared to controls. CONCLUSIONS: OCT-A was able to identify microvascular defects and VD reduction in cases of acute optic disc edema due to NA-AION and A-AION. OCT-A provides additional information in ischemic conditions of the optic nerve head.

Retinal nerve fiber layer thickness modification after internal limiting membrane peeling.

PURPOSE: To identify early and late retinal nerve fiber layer thickness (RNFLT) modification after internal limiting membrane peeling for idiopathic macular hole or epiretinal membrane and to correlate RNFLT to visual field indices. METHODS: Single-center, prospective, interventional consecutive case series. Complete ophthalmic examination, fundus images, and spectral domain optical coherence tomography were performed in 30 eyes of 30 patients before and 1, 3, and 6 months after surgery. Six peripapillary sectors (superotemporal, temporal, inferotemporal, inferonasal, nasal, superonasal) and global RNFLT were evaluated. Visual field was performed preoperatively and 6 months postoperatively. RESULTS: Significant RNFLT modification was found after surgery (P < 0.0001). Specifically, RNFLT significantly increased in all, but the temporal sectors, 1 month after surgery, and it returned to preoperative values at the third month. Six months after surgery, RNFLT was lower than basal values in the superotemporal, inferotemporal, and temporal sectors (P < 0.001, P < 0.05, and P < 0.001, respectively) with an average reduction of 18.2 ± 9.8 µm. No correlation was found between RNFLT and the visual field indices. CONCLUSION: The diffuse RNFLT increase 1 month postoperatively could be because of inflammatory responses. The reduction of RNFLT in the temporal sectors 6 months postoperatively could indicate damage to the macular retinal nerve fiber layer caused by internal limiting membrane peeling.

Subtenon injection of natural leukocyte interferon α-2a in diabetic macular edema: a case report.

BACKGROUND: To report the effect of subtenon injections of natural leukocyte interferon α-2a (IFNα) on best corrected visual acuity (BCVA) and central macular thickness (CMT) in a patient with diabetic macular edema (DME). CASE PRESENTATION: A 66-year-old man affected by DME, with glycated hemoglobin (HbA1c) at 6.9%, refractory to laser grid treatment and intravitreal injections of triamcinolone, was selected to receive a cycle of three subtenon injections/week of IFNα (1×106 IU/ml). BCVA and CMT, using spectral domain ocular coherence tomography (SD-OCT), were evaluated preoperatively and at 1 week, 1 month, 4 months, and 1 year postoperatively. BCVA and CMT were significantly improved at 1 week after the three injections (20/200 vs. 20/40 and 498 µm vs. 237 µm, respectively). BCVA remained stable during the 1-year follow-up. CMT was slightly increased, but was still lower than the baseline value (215 µm, 255 µm, and 299 µm during the follow-up visits). No adverse events were recorded, with the exception of mild subconjunctival hemorrhage at the injection site. CONCLUSIONS: IFNα, with its immunomodulatory, anti-proliferative and anti-angiogenic actions, was effective in improving BCVA and reducing CMT in refractory DME. Further randomized controlled studies are required to assess the effect of IFNα alone or in combination with other therapies for DME treatment.

Swelling of the arcuate nerve fiber layer after internal limiting membrane peeling.

PURPOSE: The purpose of the study is to report the incidence of changes of the retinal nerve fiber layer in the early postoperative period after internal limiting membrane peeling for idiopathic macular hole and epiretinal membrane surgery. METHODS: Interventional, noncomparative retrospective case series. Fifty-six eyes of 55 patients with an epiretinal membrane and 33 eyes of 31 patients with macular hole underwent pars plana vitrectomy and internal limiting membrane peeling. All patients received a complete ophthalmic examination, infrared and autofluorescence photography, and spectral-domain optical coherence tomography preoperatively and also at approximately 1 week, 1 month, and 3 months postoperatively. Vitrectomy and gas tamponade were performed with internal limiting membrane peeling after staining with Brilliant Peel. The main outcome measures were the presence of postoperative swelling of the arcuate retinal nerve fiber layer on spectral-domain optical coherence tomography, infrared and autofluorescence photographs, and its effect on best-corrected visual acuity. RESULTS: On infrared and autofluorescence photographs, 28 (31.46%) of 89 eyes with internal limiting membrane peeling exhibited swelling of the arcuate retinal nerve fiber layer 1 week to 1 month postoperatively. Swelling of the arcuate retinal nerve fiber layer increased during the first month after surgery and resolved after a mean period of 2 months. These features were best visualized by autofluorescence imaging, as three to five dark striae originating from the optic nerve head, radiating in an arcuate pattern toward the macula. Simultaneous spectral-domain optical coherence tomography scanning through the striae indicated that they correspond to areas of focal swelling of the arcuate nerve fiber layer. No significant differences were found in eyes with or without swelling of the arcuate retinal nerve fiber layer for mean age or pre- and postoperative best-corrected visual acuity (P > 0.05). CONCLUSION: Swelling of the arcuate retinal nerve fiber layer often occurs after internal limiting membrane peeling for macular hole and epiretinal membrane. It is a transient feature after surgery that does not affect visual recovery. It is best visualized using infrared and autofluorescence imaging. Simultaneous infrared and spectral-domain optical coherence tomography imaging after macular surgery can detect transient inner retinal changes, which are not visible on clinical examination.

Frequency doubling technology, optical coherence technology and pattern electroretinogram in ocular hypertension.

BACKGROUND: To assess which of three methods, namely, optical coherence tomography (OCT), pattern electroretinogram (PERG) or frequency-doubling technology (FDT), is the most sensitive and specific for detecting early glaucomatous damage in ocular hypertension (OH). METHODS: Fifty-two patients with OH (24 men and 28 women, mean age of 56 ± 9.6 years) with an intraocular pressure (IOP) > 21 mm Hg and fifty-two control patients (25 men and 27 women, mean age of 54.8 ± 10.4 years) with IOP < 21 mm Hg, were assessed. All the patients had normal visual acuity, normal optic disk and normal perimetric indices.All subjects underwent OCT, FDT and PERG. Data were analyzed with unpaired t-tests, Chi-square test and Receiver Operating Characteristic (ROC) curve analyses. RESULTS: In patients with OH, OCT showed retinal nerve fiber layer (RNFL) thinner than in control group in the superior quadrant (130.16 ± 10.02 vs 135.18 ± 9.27 µm, respectively; p < 0.011) and inferior quadrant (120.14 ± 11.0 vs 132.68 ± 8.03 µm; p < 0.001). FDT showed a significantly higher pattern standard deviation (PSD) (3.46 ± 1.48 vs 1.89 ± 0.7 dB; p < 0.001). With respect to PERG, only the amplitude showed significant differences (p < 0.044) between the two groups. ROC curve analysis revealed a sensitivity and specificity of 92% and 86%, respectively, for FDT-PSD (with an area under the ROC curve of 0.940), whereas with OCT, a sensitivity of 82% and a specificity of 74% was recorded in the inferior RNFL quadrant (with an area under the ROC curve of 0.806) finally with PERG amplitude we found a sensitivity of 52% and specificity of 77% (with an area under the ROC curve of 0.595). CONCLUSIONS: FDT is the most sensitive and specific method for detecting early glaucomatous damage in eyes with OH, and together with OCT, can be useful in identifying those patients who may develop glaucoma. TRIAL REGISTRATION: ISRCT number: ISRCTN70295497.

Capturing the Pattern of Transition From Carrier to Affected in Leber Hereditary Optic Neuropathy.

PURPOSE: To capture the key features patterning the transition from unaffected mutation carriers to clinically affected Leber hereditary optic neuropathy (LHON), as investigated by optical coherence tomography. DESIGN: Observational case series. METHODS: Four unaffected eyes of 4 patients with LHON with the first eye affected were followed across conversion to affected, from 60 days before to 170 days after conversion. The primary outcome measures were multiple timepoints measurements of peripapillary retinal nerve fiber layer (RNFL) thickness for temporal emi-side of the optic nerve (6 sectors from 6-11, clockwise for the right eye and counterclockwise for the left eye) in all patients and nasal emi-macular RNFL and ganglion cell layer (GCL) thickness in 2 patients. RESULTS: While the presymptomatic stage was characterized by a dynamic thickening of sector 8, the beginning of the conversion coincided with an increase in the thickness of the sectors bordering the papillo-acular bundle (6 and 7 for the inferior sectors, 10 and 11 for the superior sectors) synchronous with the thinning of sectors 8 and then 9. Conversely, the GCL did not undergo significant changes until the onset of visual loss when a significant reduction of thickness became evident. CONCLUSION: In this study we demonstrated that the thinning of sector 8 can be considered the structural hallmark of the conversion from the presymptomatic to the affected state in LHON. It is preceded by its own progressive thickening extending from the optic nerve head toward the macula and occurs regardless of the amount of swelling of the rest of the peripapillary fibers.

Comparison of formula accuracy for intraocular lens power calculation based on measurements by a swept-source optical coherence tomography optical biometer.

PURPOSE: To analyze the results of intraocular lens (IOL) power calculation using measurements by a swept-source optical coherence tomography (SS-OCT) optical biometer. SETTING: IRCCS G.B. Bietti Foundation, Rome, Italy. DESIGN: Evaluation of a diagnostic test instrument. METHODS: Preoperative measurements by the OA-2000 (Tomey Inc.) were taken in a consecutive series of patients undergoing cataract surgery with one IOL model (AcrySof SN60WF; Alcon Laboratories, Inc.). Measurements were entered into the following formulas: Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Hoffer Q, Holladay 1, Holladay 2, Holladay 2 with axial length adjustment, Kane, Olsen, Panacea, SRK/T, T2, and VRF. When refraction was measured at 1 month postoperatively, the mean arithmetic prediction error, the median absolute error (MedAE), and the percentage of eyes with a error of ±0.50 D or less were calculated after constant optimization. RESULTS: We enrolled 150 eyes. All formulas yielded excellent outcomes. The MedAE ranged between 0.200 D and 0.259 D, with a statistically significant difference among formulas (P = .0004). The lowest MedAE values were obtained with the Barrett, EVO, Kane, Olsenstandalone, Radial Basis Function (RBF), and T2 formulas. The percentage of eyes with a prediction error of ±0.50 D or less ranged between 80.00% and 90.67%, with a statistically significant difference (P < .0001). The Barrett, EVO, Holladay 2 with axial length adjustment, Kane, RBF, and T2 achieved the highest percentages (≥88%). CONCLUSIONS: Measurements provided by the SS-OCT optical biometer enable accurate IOL power calculation because all formulas yielded a prediction error within 0.50 D in at least 80% of eyes.

Validation of the SToP formula for calculating intraocular lens power in eyes with previous myopic excimer laser surgery.

PURPOSE: To validate the accuracy of the SToP formula for calculating the intraocular lens (IOL) power from measurements obtained with a rotating Scheimpflug camera (Pentacam) in eyes with previous myopic excimer laser surgery. SETTING: IRCCS - Fondazione Bietti, Rome, Italy. DESIGN: Retrospective case series. METHODS: Corneal curvature measurements were taken in eyes that had cataract surgery after myopic excimer laser surgery. Values from both versions of the SToP calculator (based, respectively, on the Holladay 1 and the SRK/T formulas) were compared with historical (Masket and Savini) and no-history methods (Barrett True-K, BESSt formula, equivalent K-readings, Triple-S, and Shammas). RESULTS: Fifty eyes of 50 patients with historical data were analyzed. The SToP formula based on the SRK/T achieved the lowest median absolute error (MedAE) (0.31 diopters [D]) and a higher percentage of eyes (62%) with a prediction error in refraction within ±0.5 D. Excellent outcomes were also achieved with the Masket method, the BESSt formula, the Savini method, and the Triple-S method, which led to similar MedAEs (from 0.31 to 0.37 D) and an even higher percentage of eyes with a prediction error within ±0.5 D (from 64% to 76%). The SToP formula based on the Holladay 1 was slightly less accurate. CONCLUSIONS: Several methods based on Scheimpflug camera measurements were used to successfully calculate the IOL power in eyes with previous myopic excimer laser surgery. The SToP formula based on the SRK/T was one of the best choices.

Functional assessment of a new extended depth-of-focus intraocular lens.

BACKGROUND/OBJECTIVE: This study aimed to investigate the visual performance of a new extended depth-of-focus intraocular lens (EDOF-IOL). SUBJECTS/METHODS: In this multicenter, prospective, observational study, we enrolled 97 patients who underwent cataract surgery or refractive lens exchange with implantation of the Mini Well EDOF-IOL (SIFI, Italy). Patients underwent postoperatively the following examinations between 4 and 8 weeks after surgery: corrected distance visual acuity (CDVA), reading speed with Radner's chart, distance-corrected near visual acuity (DCNVA), defocus curve, contrast sensitivity, and haloes quantitative assessment. RESULTS: In the whole sample, the mean monocular CDVA and DCNVA were, respectively, 0.02 ± 0.07 logMAR and 0.38 ± 0.15 logRAD (logarithm of the reading acuity determination). In the 67 bilaterally implanted patients, binocular CDVA and DCNVA were better (0.00 ± 0.05 logMAR and 0.26 ± 0.13 logRAD) than the corresponding monocular values (p = 0.02 and p = 0.0002, respectively). Ninety-two percent of patients bilaterally implanted reached a binocular reading speed >80 words per minute at a 0.5 logRAD print size (corresponding to the common book print size). The defocus curves showed that the EDOF-IOL provided increased depth of focus through 2.0 D of defocus, with the best performance at 1.0 and 1.5 D. Contrast sensitivity was within normal limits at all spatial frequencies. The mean visual disturbance index was 0.08 ± 0.12, suggesting low night visual disturbances. CONCLUSIONS: The new EDOF-IOL provided good visual acuity for distance, intermediate, and near vision, with no loss of contrast sensitivity and low risk of night visual disturbances.

Visual Performance of a New Extended Depth-of-Focus Intraocular Lens Compared to a Distance-Dominant Diffractive Multifocal Intraocular Lens.

PURPOSE: To investigate the clinical performance of a new extended depth-of-focus (EDOF) intraocular lens (IOL) and compare it to that of a distance-dominant diffractive multifocal IOL. METHODS: Patients implanted with an EDOF IOL (Mini Well; SIFI, Catania, Italy) inducing spherical aberration and with a multifocal IOL (ReSTOR SV25T; Alcon Laboratories, Inc., Fort Worth, TX) were analyzed. The following monocular parameters were investigated: corrected distance visual acuity (CDVA), distance-corrected near visual acuity (DCNVA), reading speed, defocus curve, contrast sensitivity, and halos and glare as quantified by a simulator (Halo & Glare Simulator; Eyeland-Design Network GmbH, Vreden, Germany) and questionnaire. RESULTS: Twenty patients with the EDOF IOL and 37 with the multifocal IOL were enrolled. No statistically significant difference was observed for CDVA. The defocus curve of the EDOF IOL revealed no gaps for the intermediate range. Statistically significant differences were observed at -1.00 diopter (D) (EDOF IOL: 0.08 ± 0.09 logMAR; multifocal IOL: 0.21 ± 0.12 logMAR; P < .0001) and -1.50 D defocus (EDOF IOL: 0.15 ± 0.11 logMAR; multifocal IOL: 0.24 ± 0.13 logMAR; P = .0122). The reading speed at 40 cm was similar at all print sizes. The mean DCNVA was the same (EDOF IOL: 0.35 ± 0.14 logRAD, multifocal IOL: 0.35 ± 0.13 logRAD). No differences in contrast sensitivity were detected. According to the simulator, halos had a smaller mean size (P = .0439) and a lower mean intensity (P = .0222) with the EDOF IOL. No statistically significant differences were detected for glare size. CONCLUSIONS: The new EDOF IOL performed similarly to a multifocal IOL at distance and near but was superior at intermediate distances. [J Refract Surg. 2018;34(4):228-235.].

Retinal dysfunction characterizes subtypes of dominant optic atrophy.

PURPOSE: To assess preganglionic retinal function using multifocal electroretinogram (mfERG) in patients affected by dominant optic atrophy (DOA) stratified by OPA1 gene mutation. METHODS: Multifocal electroretinogram (mfERG) was recorded in 18 DOA patients (DOA group, 35 eyes) and 25 age-matched healthy subjects (control group, 25 eyes). Patients were stratified in two groups based on gene mutation: missense mutation (DOA-M group, 11 eyes) and mutation causing haploinsufficiency (DOA-H group, 24 eyes). The mfERG N1-P1 response amplitude density (RAD) has been evaluated in five annular retinal areas with different eccentricity from the fovea (ring 1: 0-5 degrees, R1; ring 2: 5-10 degrees, R2; ring 3: 10-15 degrees, R3; ring 4: 15-20 degrees, R4; and ring 5: 20-25 degrees, R5) and in eight sectors on the basis of the retinal topography: temporal-superior (TS), temporal-inferior (TI), nasal-superior (NS) and nasal-inferior (NI), temporal (T), superior (S), nasal (N) and inferior (I). RESULTS: Compared to controls, DOA group revealed a significant reduction in N1-P1 RADs values in R1-R4 rings and in TI, NS and N sectors [analysis of variance (ANOVA), p < 0.01). DOA-M group showed a significant reduction in N1-P1 RADs values in R1-R5 rings and in TI, NS, NI, T, N and I sectors (p < 0.01). Dominant optic atrophy-H (DOA-H) group displayed only a significant (p < 0.01) reduction in N1-P1 RADs values, exclusively in R1 and in the NS sector. CONCLUSION: Preganglionic retinal impairment occurs in DOA with a clear genotype to retinal dysfunction association. Missense mutations are characterized by a far more severe functional impairment.

Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation.

PURPOSE: To investigate the accuracy of a new optical biometer for intraocular lens (IOL) power calculation in eyes undergoing cataract surgery. METHODS: Consecutive eyes of patients undergoing cataract surgery with the same IOL model were enrolled in a prospective cohort study. Axial length (AL) and corneal power were measured with an optical biometer based on optical low-coherence interferometry and Placido-disc corneal topography. IOL power was calculated with the Hoffer Q, Holladay 1 and SRK/T formulas. For each formula the lens constant was optimized in retrospect in order to achieve a mean prediction error (PE) of zero (difference between the predicted and the postoperative refraction). Median absolute error (MedAE) and percentage of eyes with PE ±0.50 D were calculated. RESULTS: Seventy-four eyes of 74 cataract patients were enrolled. The MedAE was 0.25 D with all formulas. A PE within ±0.50 D was obtained in 89.04% of cases with the Hoffer Q and SRK/T formulas, and in 87.67% of cases with the Holladay 1 formula. CONCLUSIONS: The optical biometer investigated in the present study provides accurate measurements for IOL power calculation.

Correction: Accuracy of optical biometry combined with Placido disc corneal topography for intraocular lens power calculation.

[This corrects the article DOI: 10.1371/journal.pone.0172634.].

Optical coherence tomography angiography of the peripapillary retina and optic nerve head in dominant optic atrophy.

Peripapillar and nerve head vessel density (VD) was measured in 10 patients affected by Dominant optic atrophy (DOA) using optical coherence tomography angiography (OCT-A) and compared to the measurements of 15 age- and gender-matched controls. DOA patients showed VD reduction, mostly in the temporal and inferotemporal peripapillary sectors, according to the preferential involvement of the papillomacular bundle. Despite poor best-corrected visual acuity (BCVA), OCT-A revealed good repeatability. VD correlated with functional (mean deviation of visual field and BCVA) and structural (retinal nerve fiber layer thickness) parameters and could be a non-invasive, quantitative tool for the monitoring of the disease and of the therapeutic approaches.

Hemorrhagic Occlusive Retinal Vasculitis After First Eye Cataract Surgery Without Subsequent Second Eye Involvement.

A case of monocular postoperative hemorrhagic occlusive retinal vasculitis (HORV) after uncomplicated bilateral cataract surgery is described. HORV is a severe syndrome that leads to painless visual loss after uncomplicated cataract surgery. The same surgical procedure was adopted in both eyes except for the use of intracameral vancomycin, which was injected only in the eye that developed HORV. Diffuse retinal ischemia with vascular sheathing and intraretinal hemorrhages were detected during the fourth postoperative day. Despite treatment, the patient developed severe neovascular glaucoma. This case supports the causative role of vancomycin in the pathogenesis of HORV and suggests avoiding it for chemoprophylaxis. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:764-766.].

Agreement Between Predicted and Measured Ablation Depth After Femtosecond Laser-Assisted LASIK for Myopia.

PURPOSE: To investigate agreement between the predicted ablation depth calculated by the EX500 excimer laser (Wavelight Laser Technologie AG, Erlangen, Germany) and the measured ablation depth in eyes that have undergone femtosecond laser-assisted LASIK (FS-LASIK) for myopia. METHODS: Corneal thickness was measured with a rotating Scheimpflug camera preoperatively and 3 months postoperatively and the difference between these values was defined as the measured ablation depth. The difference between the predicted and the measured ablation depth was defined as the difference in ablation depth (ΔAD). RESULTS: In 85 eyes of 85 patients, no statistically significant difference was detected between the mean predicted ablation depth (66.33 ± 24.15 µm) and the measured ablation depth at the thinnest corneal location (67.04 ± 30.94 µm), the corneal apex (67.52 ± 31.22 µm), or the pupil center (67.73 ± 31.48 µm). Bland-Altman plots revealed moderate agreement for measurements at the thinnest point (95% limits of agreement [LoA]: -25.13 to 23.70 µm), corneal apex (95% LoA: -24.70 to 22.33 µm), and pupil center (95% LoA: -25.30 to 22.51 µm), with a proportional bias between the average ablation depth and ΔAD. The predicted ablation depth was overestimated in eyes with lower correction and underestimated in eyes with higher correction. CONCLUSIONS: Moderate agreement between the predicted and measured ablation depth warrants caution when planning myopic FS-LASIK and calculating the residual bed thickness and percent tissue altered. When higher amounts of correction are planned, the laser software may underestimate the predicted ablation depth.

Macular nerve fibre and ganglion cell layer changes in acute Leber's hereditary optic neuropathy.

AIMS: To evaluate longitudinal retinal ganglion cell inner plexiform layer (GC-IPL) and macular retinal nerve fibre layer (mRNFL) thickness changes in acute Leber's hereditary optic neuropathy (LHON). METHODS: Six eyes of four patients with LHON underwent SD-OCT (optical coherence tomography) at month 1, 3, 6 and 12 after visual loss. In two eyes, the examination was carried out in the presymptomatic stage. The relationship and curves for area under the receiver operator characteristic (AUROC) were generated to assess the ability of each parameter to detect ganglion cell loss. RESULTS: Significant longitudinal thinning of GC-IPL and mRNFL was detected in LHON. GC-IPL thinning was detectable in the deviation map during the presymptomatic stage in the inner ring of the nasal sector and then it progressively extended following a centrifugal and spiral pattern. Similarly, mRNFL thinning began in the inferonasal sector and it progressively extended. No further statistically significant changes were detected after month 3. The highest level of AUROC values at 1 month were detected in the nasal sectors and inferonasal mRNFL thickness reached AUROC value=1. All the parameters were equally able to detect ganglion cell loss from month 2 to 12. CONCLUSIONS: The natural history of GC-IPL thinning follows a specific pattern of reduction, reflecting the anatomical course of papillomacular fibres. Month 6 represents the end of GC-IPL loss. GC-IPL and mRNFL thinning is detectable before onset of visual loss. These observations can help future therapeutic approaches for both LHON carriers at high risk of conversion and patients with acute early LHON.

Changes in Choroidal Thickness follow the RNFL Changes in Leber's Hereditary Optic Neuropathy.

Leber's hereditary optic neuropathy (LHON) is typically characterized by vascular alterations in the acute phase. The aim of this study was to evaluate choroidal changes occurring in asymptomatic, acute and chronic stages of LHON. We enrolled 49 patients with LHON, 19 with Dominant Optic Atrophy (DOA) and 22 healthy controls. Spectral Domain-Optical Coherence Tomography (SD-OCT) scans of macular and peripapillary regions were performed in all subjects, to evaluate macular and peripapillary choroidal thickness, and retinal nerve fiber layer (RNFL) thicknes. Macular and peripapillary choroidal thicknesses were significantly increased in the acute LHON stage. On the contrary, macular choroidal thickness was significantly reduced in the chronic stage. Furthermore, peripapillary choroidal thickness was decreased in chronic LHON and in DOA. Both RNFL and choroid had the same trend (increased thickness, followed by thinning), but RNFL changes preceded those affecting the choroid. In conclusion, our study quantitatively demonstrated the involvement of the choroid in LHON pathology. The increase in choroidal thickness is a feature of the LHON acute stage, which follows the thickening of RNFL. Conversely, thinning of the choroid is the common outcome in chronic LHON and in DOA.