Dry eye and cataract surgery: Narrative review and recommendations for management.

Cataract surgery is the most frequently performed surgical procedure in the elderly in Western countries and patients' expectations for postoperative outcomes are very high.Dry eye disease (DED) is a common multifactorial symptomatic disease of the ocular surface with a complex etiopathogenesis and a prevalence significantly increasing with age.Cataract surgery and DED have a complex relationship, which needs to be acknowledged, understood, and properly managed, as suggested by daily clinical experience and growing scientific evidence. The surgical procedure can have a relevant impact on the tear film and the ocular surface, and it can, usually transiently, induce or exacerbate DED symptoms. Moreover, preoperative DED can affect surgical refractive outcomes, while postoperative DED symptoms can significantly worsen patients reported outcomes and satisfaction.At the end of this narrative review summarizing the evidence on this topic, the "Dry Eye and Cataract Surgery" subcommittee of the DROPS workshop formulated some recommendations for ocular surface and DED management pre-, intra-, and post-cataract surgery.

Corneal Epithelial Regeneration: Old and New Perspectives.

Corneal blindness is the fifth leading cause of blindness worldwide, and therapeutic options are still often limited to corneal transplantation. The corneal epithelium has a strong barrier function, and regeneration is highly dependent on limbal stem cell proliferation and basement membrane remodeling. As a result of the lack of corneal donor tissues, regenerative medicine for corneal diseases affecting the epithelium is an area with quite advanced basic and clinical research. Surgery still plays a prominent role in the treatment of epithelial diseases; indeed, innovative surgical techniques have been developed to transplant corneal and non-corneal stem cells onto diseased corneas for epithelial regeneration applications. The main goal of applying regenerative medicine to clinical practice is to restore function by providing viable cells based on the use of a novel therapeutic approach to generate biological substitutes and improve tissue functions. Interest in corneal epithelium rehabilitation medicine is rapidly growing, given the exposure of the corneal outer layers to external insults. Here, we performed a review of basic, clinical and surgical research reports on regenerative medicine for corneal epithelial disorders, classifying therapeutic approaches according to their macro- or microscopic target, i.e., into cellular or subcellular therapies, respectively.

Sutureless "Contact Lens Sandwich" Technique for Amniotic Membrane Therapy of Central Corneal Ulcers.

PURPOSE: To describe a new technique for sutureless and glue-free amniotic membrane transplantation (AMT) and to investigate its effectiveness to treat corneal persistent epithelial defects (PEDs), compared to bandage contact lens (BCL) application alone. METHODS: We performed AMT with "contact lens sandwich technique" (CLS-AMT) in 8 consecutive patients with central/para-central (up to 4.00 mm from the geometrical centre) PED/ulceration and we retrospectively compared the results with 11 BCL procedures. RESULTS: The procedures were performed successfully with no complications.CLS-AMT showed significantly shorter healing time than BCL (24.0 ± 19.1 vs 42.9 ± 14.6 days; P < 0.05, Mann-Whitney test). Recurrence rates were 12% and 27% for CLS-AMT and BCL, respectively. CONCLUSION: CLS-AMT technique, based on the suction effect due to the superposition of a bandage contact lens on the AM-ring complex, represents a quick, low cost, easy to perform and nearly non-invasive AMT technique. This approach is able to provide adequate fixation of AM, and it seems to be a safe and effective treatment for patients with PEDs.

Intraocular pressure control after combined phacotrabeculectomy versus trabeculectomy alone.

PURPOSE: We compared the efficacy and safety of trabeculectomy and phacotrabeculectomy in patients with glaucoma. MATERIALS AND METHODS: We retrospectively analyzed consecutive patients who underwent trabeculectomy or phacotrabeculectomy. Patients in the trabeculectomy group were pseudophakic. We established three different intraocular pressure (IOP) thresholds (A: <21 mmHg, B: <18 mmHg, and C: <15 mmHg) to measure complete (without medication) and qualified (with medication) success. Success criteria were analyzed through Kaplan-Meier survival curves. RESULTS: Sixty-seven eyes were included (40 trabeculectomy, 27 phacotrabeculectomy). The mean follow-up period was 25.70 ± 14.439 months. The baseline characteristics were similar between the groups. The complete and qualified success rates according to criterion C were significantly higher in the trabeculectomy group (p = 0.033, p = 0.021, respectively); however, there was a trend toward a higher success rate for all criteria in favor of trabeculectomy. Bleb needling was more frequent in the phacotrabeculectomy group. The mean IOP significantly decreased from 26.46 ± 7.07 to 12.27 ± 4.06 at 12 months (p < 0.001). The final mean IOP was significantly lower in the trabeculectomy than in the phacotrabeculectomy group (10.95 ± 3.08 vs 13.00 ± 4.56, p = 0.0003). CONCLUSION: In pseudophakic eyes, trabeculectomy alone achieves a higher success rate, lower mean IOP, and less frequent bleb needlings. More frequent follow-up and prolonged postoperative use of high-dose topical steroids should be considered in patients undergoing phacotrabeculectomy.

Optical coherence tomography angiography application to pigmented iris: Could a new index quantify blood flow?

PURPOSE: To assess the blood flow and vascular visibility of irises in relation to pigmentation and pupil size, using an anterior segment optical coherence tomography angiography (OCTA). MATERIALS AND METHODS: This is a cross-sectional study. OCTA images were acquired in the nasal and temporal quadrants from a cohort of 30 healthy subjects in photopic (miosis) and scotopic (mydriasis) conditions. Patients were divided according to iris color (less pigmented: group L vs more pigmented: group D). Vascular parameters (vessel density (VD), vessel length density (VLD), fractal dimension (FD)) were applied and compared among groups L and D, location and different pupil status. A novel vascular index called Luminance Index (LI) was developed and applied in order to quantify vascular flow and evaluate its variation in photopic and scotopic conditions. Multivariable analyses were performed to evaluate possible predictors of VD and LI. RESULTS: No differences were found for all vascular measurements (VD, VDL, FD, LI) between nasal and temporal quadrants. All vascular measurements were higher in group L than in group D (p < 0.05), except for LI and FD in photopic condition. In group L, all vascular parameters increased (p < 0.001) after dark adaptation. In group D, only LI increased after dark adaptation (p < 0.001). Pigmentation and iris thickness were significantly associated with VD in scotopic and photopic conditions, and with LI only in scotopic condition. CONCLUSIONS: Pigmentation still remains a major issue for vascular visibility. Quantitative and qualitative vascular changes follow pupil size variation. LI could be a new surrogate to quantify blood flow.

Angle-supported intraocular lens versus scleral-sutured posterior chamber intraocular lens in post-cataract surgery aphakic patients: two-year follow-up cost-effectiveness analysis.

PURPOSE: To compare visual, anatomical and economical outcomes of patients with secondary anterior chamber intraocular lens (AC-IOL) implantation and secondary scleral fixated intraocular lens (SF-IOL) implantation. METHODS: In this retrospective observational study, 38 aphakic patients after complicated phacoemulsification divided in two groups, AC-IOL group (17 patients receiving AC-IOL implantation) and SF-IOL group (21 patients receiving SF-IOL implantation). Corrected distance visual acuity (CDVA), patient reported visual outcome (VF-14) and endothelial cell density (ECD) were measured at baseline and two-year follow-up. Complication rate was registered. The global cost of each procedure and the incremental cost-effectiveness ratio (ICER) were calculated. RESULTS: No statistically significant difference was found in CDVA (logMAR 0.24 ± 0.17 vs. 0.32 ± 0.26, p = 0.27), VF-14 (68 ± 18 vs. 61 ± 20, p = 0.24), ECD (1456.48 ± 525.15 vs. 1341.71 ± 374.33, p = 0.48) and overall complication rate (p = 0.79) postoperatively between the SF-IOL group and the AC-IOL group. The ECD loss rate was significantly higher in the AC-IOL group (15.5% vs. 3.5%, p = 0.004). The average global cost of the two procedures was higher in the SF-IOL group (p < 0.005) and ICER showed an additional payment of 693 € for each patient in SF-IOL group against a saving of 186 endothelial cells 2 years postoperatively. CONCLUSION: AC IOL and SF-IOL implantation showed similar outcomes in terms of visual function and safety profile. Higher ECD loss was found in AC-IOL group. The global cost of implantation was significantly lower for AC-IOL, but the ICER seems to justify the SF-IOL implantation in patients with low ECD.

Prevalence of SARS-CoV-2 amongst ophthalmologists throughout the first and second waves of the pandemic.

ABSTRACT: The study aims to investigate the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among ophthalmology unit staff throughout the first and second waves of the outbreak, in order to verify the effectiveness of the measures adopted in containing the contagion.A retrospective observational study was conducted involving staff members, who received a naso/oropharyngeal swab when complaining of SARS-CoV-2 symptoms and once a month as a screening measure. They were tested for SARS-CoV-2 antibodies as a screening measure during the first and the second wave. Clinical activities performed during the outbreak were compared with those performed during the same period in 2019 and correlated with the number of coronavirus disease-2019 eye care workers.Analysis included 25 workers. Clinical infection was 0% and 12% whereas the prevalence of SARS-CoV-2 antibodies ranged from 4% to 8% in the first and second wave, respectively. The increase in the prevalence of SARS-CoV-2 infection between the first and the second wave was not significant (1/25 vs 3/25, P = .6092). Clinical activities significantly decreased during the first wave compared with the same period in 2019 (3256 vs 10,075, P < .0001, -68% to 2019), but increased during the second wave (8208 vs 3256, P < .0001, +152% to the first wave).Despite the increase in routine activities during the second wave, we did not observe a significant increase in SARS-CoV-2 prevalence. Strict protection measures seemed to contain the rate of contagion among the ophthalmology unit members even in a high-volume clinical setting in one of the most affected area by the coronavirus disease-2019 outbreak.

Impact of Adherence (Compliance) to Oral Acyclovir Prophylaxis in the Recurrence of Herpetic Keratitis: Long-Term Results From a Pediatric Cohort.

PURPOSE: To evaluate the long-term role of adherence to oral acyclovir prophylaxis in reducing the risk for recurrent herpes simplex virus keratitis (HSK) in children. METHODS: A retrospective cohort study was performed including all pediatric patients 16 years or younger) with their first HSK diagnosis and treatment at our center. Children were started on a standardized oral acyclovir prophylactic regimen after the acute phase. Adherence to prophylaxis was assessed monthly through parent interviews. The possible association between any recurrence (not only the first) and exposure to acyclovir prophylaxis was evaluated using random-effects multivariate logistic regression. RESULTS: A total of 20 eyes of 17 patients (8 boys and 9 girls) were included. The mean follow-up time was 3.5 years. Adherence to acyclovir prophylaxis was registered in 100% of patients with no recurrences and in 36.4% of patients with 1 or more recurrences (P = 0.035). All other tested variables (time of follow-up, sex, age, infectious diseases, underlying hematological diseases, eye, and HSK type) did not differ between the 2 groups. The multivariate model confirmed the lower risk for recurrence in patients who were compliant to therapy (adjusted odds ratio 0.04, 95% confidence intervals 0.00-0.42, P = 0.008). No adverse effects were recorded during follow-up. CONCLUSIONS: Oral acyclovir prophylaxis is a safe and an effective medical treatment for recurrent HSK and its long-term efficacy is associated with compliance to the therapy.

Medical management of pediatric glaucoma: lessons learned from randomized clinical trials.

PURPOSE: To critically discuss the randomized clinical trials (RCTs) on glaucoma medical therapy for the management of pediatric glaucoma. METHODS: RCTs on glaucoma drugs carried out on pediatric subjects with ocular hypertension and glaucoma were identified through systematic searches. The methods of the RCTs and the safety and the efficacy of the glaucoma drugs were reviewed and discussed. RESULTS: We included five RCTs. One study compared dorzolamide with 0.5% timolol gel; one brinzolamide with 0.5% levobetaxolol; one 0.25% betaxolol, 0.25% timolol gel, and 0.5% timolol gel; one latanoprost with 0.5% timolol; and one travoprost with 0.5% timolol. The primary outcome was safety for two studies and efficacy for three studies. None of the RCTs was powered to detect statistically significant differences in intraocular pressure (IOP) between treatments. In total, 658 subjects received at least one dose of study medication. Beta-blockers were administered to 359 patients, carbonic anhydrase inhibitor (CAI) to 154, and prostaglandins to 145 patients. IOP-lowering efficacy ranged from 20 to 23% for CAI, from 9 to 36% for beta-blockers, and from 26 to 27% for prostaglandins. The percentage of responders was 50% for CAI, ranged from 38 to 74% for beta-blockers and from 60 to 83% for prostaglandins. Two patients receiving timolol experienced a systemic, drug-related serious adverse event (one patient bradycardia and one pneumonia). Systemic, nonserious drug-related events occurred in 15 patients randomized to beta-blockers and in 8 patients randomized to CAI. No adverse events occurred in children treated with prostaglandins. CONCLUSION: RCTs that are available on medical therapy for glaucoma are few and underpowered. The proportion of responders is lower in children; however, in subjects who are responders, the efficacy of glaucoma drugs seemed to be comparable to that in adults. As systemic adverse events have been reported, including serious events with timolol, a particular attempt to minimize the absorption of the drug (using the lowest dose and the gel formulation of beta-blockers or considering the lacrimal punctum occlusion) and a follow-up that is more frequent and more focused on safety should be considered in pediatric subjects who are on topical glaucoma medications.

The Ocular Surface Frailty Index as a Predictor of Ocular Surface Symptom Onset after Cataract Surgery.

PURPOSE: The identification of healthy persons more susceptible to dry eye (DED) symptoms developing after surgery remains an unmet need. We performed this study to build a new Ocular Surface Frailty Index (OSFI) and assess its predictive value for DED symptom onset after cataract surgery. DESIGN: Single-center, observational, longitudinal study. PARTICIPANTS: We screened 405 consecutive patients scheduled for phacoemulsification for age-related cataract. Two hundred eighty-four eyes of 284 patients without preoperative DED symptoms who underwent uneventful cataract surgery were included in the analysis. METHODS: We built a tool to assess ocular surface frailty. Starting from a preliminary list of 19 potential items, the final OSFI, including 10 deficits in ocular surface health, factors potentially able to affect it, or both, was developed by a stepwise approach. Preoperative OSFI results were calculated for each enrolled patient and diagnostic tests for DED were performed at the screening visit and 1 week, 1 month, and 3 months after surgery. We evaluated the ability of OSFI to predict the presence of DED symptoms at 1 month or 3 months after surgery, or both. MAIN OUTCOME MEASURES: The rate of ocular surface symptoms at 1 month or 3 months after surgery, or both. RESULTS: Our patients' OSFI scores ranged from 0 to 0.666, with a median value of 0.200. The percentage of patients with postsurgical ocular surface symptoms was 17%. Using an OSFI cutoff of 0.300, we identified a small group (19% of the asymptomatic patients) with frail ocular surfaces who showed a significantly higher risk of postsurgical DED symptoms develop (50.0% vs. 9.6%; P < 0.001, chi-square test). Logistic regression analysis showed that OSFI results of 0.3 or more (but not age, gender, or any preoperative sign) was a good predictor of ocular surface symptom onset (odds ratio, 9.45; 95% confidence interval, 4.74-18.82). Regression remained significant when performed on 200 bootstrapped samples. CONCLUSIONS: The OSFI can be calculated easily and quickly using noninvasive and low-tech procedures, and it proved to be predictive of postoperative DED symptoms onset. This novel tool may allow cataract surgeons to perform a useful preoperative personalized risk assessment.

Mushroom keratoplasty and contact lens application: Strategy for management of a pediatric eye injury.

We show the challenging visual rehabilitation of a penetrating eye injury in a child with wide central corneal scar and aphakia. A 9-year-old male patient underwent combined surgery, including membranectomy with pupilloplasty and mushroom penetrating keratoplasty. Corneal transparency was restored; aphakia and irregular astigmatism were corrected first with a rigid gas-permeable contact lens (CL) and then, successfully, with hybrid CL. We discuss the surgical treatment used to restore corneal transparency and the choice of the best CL to overcome irregular astigmatism and aphakia.

Efficacy of atropine 0.01% for the treatment of childhood myopia in European patients.

PURPOSE: To evaluate the efficacy and safety of atropine 0.01% in slowing myopia progression in European paediatric patients. METHODS: Retrospective, medical records review study. Medical charts of paediatric patients with a myopia progression > 0.5 D/year treated with atropine 0.01% for at least 1 year were included. Patients receive a complete ophthalmic examination before and 12 months after initiation of atropine treatment. A group of myopic untreated children serves as a control group. The rate of myopia progression at baseline and 12 months after treatment with atropine was evaluated. The rate of myopia progression in treated and untreated patients was also compared. Adverse events were recorded. RESULTS: Medical records of 52 treated and 50 control subjects were analysed. In the atropine group, the mean rate of myopia progression after 12 months of treatment (-0.54 ± 0.61 D) was significantly slower compared with the baseline progression (-1.20 ± 0.64 D; p < 0.0001) and to the progression in the control group (-1.09 ± 0.64; p < 0.0001). The responders patients were 41/52 (79%), whereas 11/52 patients (21%) showed a progression > 0.50 D despite treatment. The only adverse event was temporary photophobia in five patients (9.6%), severe adverse events were not reported, and none of the patients discontinued the treatment. CONCLUSION: Low-dose atropine significantly slowed the rate of myopia progression in European paediatric patients with a favourable safety profile.

Dry Eye in Vernal Keratoconjunctivitis: A Cross-Sectional Comparative Study.

The purpose of this comparative cross-sectional study was to investigate the use of standardized clinical tests for dry eye in pediatric patients with active and quiet vernal keratoconjunctivitis (VKC) and to compare them with healthy children.We recruited 35 active VKC, 35 inactive VKC, and 70 age-matched control healthy subjects. Each child underwent a complete eye examination, including visual analog scale symptoms assessment, biomicroscopy, fluorescein break-up time (BUT), corneal fluorescein and conjunctival lissamine green staining, corneal esthesiometry, Schirmer test with anesthetic, and meibomian glands inspection and expression.Active VKC patients showed significantly increased symptoms and signs of ocular surface disease, compared with the other 2 groups. Inactive VKC patients, compared with control subjects, showed increased photophobia (P < 0.05; Mann-Whitney U test), conjunctival lissamine green staining and Schirmer test values, and reduced BUT and corneal sensitivity [P < 0.05 by analysis of variance (ANOVA) least significant difference posthoc test for BUT and Schirmer; P < 0.001 by Mann-Whitney U test for lissamine green staining and corneal sensitivity].Our results confirm the association between VKC and short-BUT dry eye. This syndrome seems to affect the ocular surface in quiescent phases too, determining abnormalities in tear film stability, epithelial cells integrity, and corneal nerves function. The very long-term consequences of this perennial mechanism of ocular surface damage have not been fully understood yet.

The dynamic healing process of idiopathic macular holes after surgical repair: a spectral-domain optical coherence tomography study.

PURPOSE: To analyze progressive changes of the outer retina after vitrectomy for macular hole (MH) repair. METHODS: Nineteen consecutive patients underwent vitrectomy for idiopathic MH. Spectral domain optical coherence tomography (SD-OCT) examinations were performed pre- and postoperatively during follow-up visits at 1, 3, 6, 9, and 12 months. Active eye-tracking technology ensured that the same scanning location was identified each time. RESULTS: Ten eyes showed a normal external limiting membrane (ELM) at 1 month after surgery and 15 eyes at 3 months. The ELM was already continuous in 79% of the eyes with persistent outer foveal defects during follow-up. No eyes revealed a continuous inner segment/outer segment (IS/OS) line at 1 month, only one eye at 3 months, and 10 eyes at 12 months. No eyes had a disrupted ELM with an intact IS/OS line. Foveal cysts were visible in three eyes at 1 month and in eight eyes during follow-up. The cystic space gradually filled, resulting in a continuous IS/OS line in five of these eyes. Recovery of ELM, IS/OS, and outer nuclear layer (ONL) determined most of visual acuity improvement. The ONL appeared normal in the 10 eyes with an intact IS/OS line at last follow-up. By contrast, it was disrupted in 7 of 9 eyes with a final persistent outer foveal defect. CONCLUSIONS: The ELM is the first structure to recover after MH closure. Foveal cysts may develop during follow-up, and in the presence of an intact ONL, they may gradually fill with complete recovery of the IS/OS junction.

Transcorneal suture fixation of posterior lamellar grafts in eyes with minimal or absent iris-lens diaphragm.

PURPOSE: To describe a technique that uses a transcorneal suture for safe delivery and fixation of donor tissue during Descemet stripping automated endothelial keratoplasty in patients that are at risk of graft dislocation into the vitreous cavity as a result of minimal or absent iris-lens diaphragm. DESIGN: Interventional case series. METHODS: Thirteen eyes with endothelial decompensation and inadequate iris-lens diaphragm underwent modified Descemet stripping automated endothelial keratoplasty surgery. A 10-0 Prolene suture (Ethicon Inc) was passed through the endothelial graft and used to pull the graft into the eye and anchor it onto the recipient cornea. Best-corrected visual acuity, refraction, and complications were recorded. RESULTS: Preoperative best-corrected visual acuity was less than 20/200 in all cases. Eleven patients had a pre-existing comorbidity (glaucoma, n = 8; previous retinal detachment, n = 2; epiretinal membrane n = 1). Average follow-up was 11.3 months (range, 3 to 36 months). No graft dislocation occurred during surgery. After surgery, graft detachment was noted in 2 cases and rebubbling succeeded in achieving reattachment. All patients had successful attachment of the endothelial graft. Postoperative best-corrected visual acuity improved in 11 of 13 patients and remained unchanged in 2 patients. CONCLUSIONS: In patients with insufficient iris-lens diaphragm, this technique allowed safe graft delivery, prevented intraoperative and postoperative graft dislocation, and facilitated successful rebubbling in case of postoperative graft detachment.

Automated software analysis of corneal micrographs for peripheral neuropathy.

PURPOSE: A relationship has been reported between the presence of peripheral neuropathy and the density and shape of corneal nerve fibers. Peripheral neuropathy is a debilitating condition that arises from many common health problems, and its presence is often confirmed with an invasive clinical test called intramuscular electromyography (EMG). In this study, the possibility of developing an alternative or adjunct test to EMG based on the appearance of nerve fibers in corneal micrographs was explored. Since corneal imaging is virtually noninvasive compared with EMG, such a test may be administered more liberally and frequently, before neuropathy symptoms occur. METHODS: A software program that automatically traces nerve fibers in corneal micrographs and generates measures based on these traces was implemented. This software was applied to a database of images collected by confocal laser scanning corneal microscopy from diabetic subjects whose levels of neuropathy were measured with EMG and from healthy subjects. RESULTS: Trends in the nerve fiber density and various measures of shape were calculated and observed, to explore the possibility of using these measures as a clinical tool for corroborating symptoms, confirming an evaluation, or evaluating risk factors for developing neuropathy. CONCLUSIONS: Preliminary statistical trends show a potential for measuring and observing neuropathy severity or for providing an objective risk measure for a patient's ensuing condition. More work is needed in the development of the measures and in their testing to prove that the measures can be made repeatable in a clinical environment.

Evaluation of prostaglandin analogue effects on corneal keratocyte density using scanning laser confocal microscopy.

PURPOSE: To determine if treatment with prostaglandin (PG) analogues affects keratocyte density as an indirect measure of extracellular matrix in the corneal stroma. PATIENTS AND METHODS: In this case control study, 129 eyes from 68 patients were examined: 52 eyes had only PG analogue therapy for at least 3 years, 37 eyes had only ß-adrenergic blocker therapy for at least 3 years, and 40 control eyes were without therapy. Scanning laser confocal microscopy was carried out, and each corneal stroma was subdivided into the anterior, midstroma, and posterior stroma. Keratocyte density was determined from the images by manual counting. RESULTS: Keratocyte densities in the entire stroma and in 2 stromal layers were significantly higher in patients with PG analogue therapy compared with control patients (entire stroma, P<0.001; anterior stroma, P=0.001; posterior stroma, P=0.016). Keratocyte density in the PG analogue therapy patients was also greater compared with the ß-adrenergic blocker patients (entire stroma, P<0.001; anterior stroma, P<0.001; mid-stroma P=0.023, posterior stroma P=0.007). There were no significant differences between the control and ß-adrenergic blocker groups. Overall, the density increase for the PG analogue group was greatest in the anterior stroma. CONCLUSIONS: PG analogue therapy increased the keratocyte density in each layer of corneal stroma, but more significantly in the anterior stroma than in the midstroma or the posterior stroma. The increased keratocyte density might be the result of diminished extracellular matrix, possibly owing to the known activation of matrix metalloproteinases and inhibition of tissue inhibitors of the metalloproteinases.

Artifacts in automatic retinal segmentation using different optical coherence tomography instruments.

PURPOSE: The purpose of this study was to compare and evaluate artifact errors in automatic inner and outer retinal boundary detection produced by different time-domain and spectral-domain optical coherence tomography (OCT) instruments. METHODS: Normal and pathologic eyes were imaged by six different OCT devices. For each instrument, standard analysis protocols were used for macular thickness evaluation. Error frequencies, defined as the percentage of examinations affected by at least one error in retinal segmentation (EF-exam) and the percentage of total errors per total B-scans, were assessed for each instrument. In addition, inner versus outer retinal boundary delimitation and central (1,000 microm) versus noncentral location of errors were studied. RESULTS: The study population of the EF-exam for all instruments was 25.8%. The EF-exam of normal eyes was 6.9%, whereas in all pathologic eyes, it was 32.7% (P < 0.0001). The EF-exam was highest in eyes with macular holes, 83.3%, followed by epiretinal membrane with cystoid macular edema, 66.6%, and neovascular age-related macular degeneration, 50.3%. The different OCT instruments produced different EF-exam values (P < 0.0001). The Zeiss Stratus produced the highest percentage of total errors per total B-scans compared with the other OCT systems, and this was statistically significant for all devices (P < or = 0.005) except the Optovue RTvue-100 (P = 0.165). CONCLUSION: Spectral-domain OCT instruments reduce, but do not eliminate, errors in retinal segmentation. Moreover, accurate segmentation is lower in pathologic eyes compared with normal eyes for all instruments. The important differences in EF among the instruments studied are probably attributable to analysis algorithms used to set retinal inner and outer boundaries. Manual adjustments of retinal segmentations could reduce errors, but it will be important to evaluate interoperator variability.