Topical insulin for refractory persistent corneal epithelial defects.

The aim was clinical evaluation of the efficacy of topical insulin eye drops in patients with refractory persistent epithelial defects (PEDs). This prospective non-randomized investigation was conducted to examine the efficacy of insulin eye drops in treating patients with PEDs that did not respond to conventional therapy. A total of twenty-three patients were included in the study, and they were administered insulin eye drops formulated as 1 U/mL, four times a day. The rate of epithelial defect resolution and time to complete corneal re-epithelialization were considered primary outcome measures. The relative prognostic impact of initial wound size and other parameters, including age, sex, smoking, diabetes, and hypertension were also analyzed. The results showed that during follow-up (maximum 50 days), a total of 16 patients (69.6%) achieved improvement. Insulin eye drops significantly reduced the corneal wounding area in 75% of patients with small epithelial defects (5.5 mm2 or less) during 20 days. Only 61% of patients with moderate epithelial defects (5.51-16 mm2) showed a significant recovery in 20-30 days. Also, 71% of patients with a defect size greater than 16 mm2, demonstrated a significant improvement in the rate of corneal epithelial wound healing in about 50 days. In conclusion topical insulin reduces the PED area and accelerates the ocular surface epithelium wound healing.

Pseudodendritic keratitis in citrullinemia; a report of an unusual and novel ocular finding in this metabolic disorder.

Purpose: To report a 15 year old girl with citrullinemia type 1 and 2 accompanied by neurologic signs and symptoms and a novel ocular complaint in cornea like tyrosinemia type 2. Observations: A 15 year old female was admitted with decreased consciousness and neurologic signs and symptoms. Citrulinemia was discovered through metabolic testing. Later genetic studies revealed mutations in both ASS1 and SLC25A13 genes. Two years after the first presentation, the patient was re-admitted with complaints of bilateral photophobia and tearing. Biomicroscopic examination revealed bilateral corneal haziness with pseudodendritic lesions like tyrosinemia type 2 that were subsided with protein restriction and the use of urea cycle disease (UCD) formula. Conclusions and importance: Citrullinemia is the inherited autosomal recessive disorder of urea cycle that leads to ammonia and accumulation of other toxic substances in the blood. Two types of Citrullinemia have been defined. Citrullinemia type 1, caused by deficiency or reduction in argininosuccinate synthetase enzyme activity due to damaging mutation in ASS1 gene. Citrullinemia type 2 as another subtype is caused by the absence or dysfunction of the mitochondrial membrane carrier protein (SLC25A13), also called CITRIN. Pseudodendritic keratitis is a rare condition that may be seen with tyrosinemia type 2. The association of this ocular complaint with citrullinemia has not been described previously. Awareness of this phenomenon may improve the diagnosis and management of citrullinemia patients.

Familial primary calcific band-shaped keratopathy with late onset systemic disease: a case series and review of the literature.

BACKGROUND: Familial calcific band-shaped keratopathy (BSK) is a very rare disease, with no underlying cause. There is no underlying disease in this form of the disease. This article introduces a family with seven children, three of whom were diagnosed with familial primary calcific BSK. One of them developed a systemic disease 38 years after ocular manifestation. CASE PRESENTATION: In this case report, three Iranian siblings from a family with familial calcific band-shaped keratopathy (BSK) are introduced. Systemic and ocular examinations performed on these patients indicated the occurrence of chronic kidney disease in the older child, a 41-year-old woman, 38 years after ocular manifestation. The examinations conducted on the other two siblings revealed no pathological findings. The 41-year-old sister and 37-year-old brother underwent unilateral deep anterior lamellar keratoplasty (DALK), while the 33-year-old sister underwent bilateral superficial keratectomy (SK). CONCLUSION: Considering the late onset of systemic disease in one of the siblings diagnosed with familial calcific band-shaped keratopathy (BSK), it is crucial to emphasize the necessity of long-term follow-up for these patients and their families.

An innovative optics lab design for residency training in ophthalmology.

Proper understanding of the optical function of the eye is the foundation of clinical understanding of ophthalmologists. Although teaching principals of optics has always been a part of ophthalmology residency curriculum, it seems that successful strategies other than lecture-based methods are needed to engage students and facilitate the understanding of optical principals. A collaborative team of physicists (optics Ph.D.), ophthalmologists and medical education experts designed an optics lab for ophthalmology residents to help them practically simulate different optical phenomena. The educational course consisted of 4 sessions of 90 min to practice the optical tests using the lab instruments. Each class consisted of 6-9 residents, divided into 3 groups with a fully equipped unit, and two mentors (an optics Ph.D. professor and an ophthalmology professor). A quasi-experimental design with pre-post test was used to evaluate the effectiveness of the training workshop in changing the ophthalmology residents' optical knowledge and attitude. Thirty-five residents participated in the study. The average score of residents' performance before the workshop was 5.21 (out of 100), which increased significantly to 66.1 after the workshop. Also, the average knowledge of residents, which was measured as self-reported, increased significantly from 28.85 to 71.09. The average score of students' attitudes and interest was increased from 40.49 to 74.81. It seems that training workshops and labs are effective to bring about change in knowledge and attitude of ophthalmology residents toward optics as a new teaching strategy that would be implemented in their curriculum.

Comparison of corneal measurements using two different Scheimpflug analyzers in Sirius and Pentacam devices.

The aim was to compare measurements of anterior segment biometry parameters using two Scheimpflug tomographies, Pentacam and Sirius to assess the agreement. Prospective cross-sectional observational study. A total of 60 eyes of 30 healthy subjects were included and evaluated with Pentacam followed by Sirius imaging. Corneal indices were performed with two modalities in both eyes including; apical corneal thickness (ACT), corneal thickness at pupil site(PCT), thinnest corneal thickness (TCT), anterior chamber depth (ACD), chamber angle, chamber volume, cornea volume, mean front keratometry (FKm), the radius of corneal curvature at the anterior and posterior surface in steep and flat meridian, anterior astigmatism values, pupil diameter, and horizontal corneal diameter. The Bland-Altman graph and ICC (intra-class correlation were used to establish an agreement and present the similarity of the findings. Most parameters showed perfect agreement. In both devices, the ICC was more than 0.91 in all measurements except for ACD (ICC = 0.820), cylinder axis (ICC = 0.520), TCT(ICC = 0.881), ACT(ICC = 0.672), PCT (ICC = 0.882), chamber angle (ICC = 0.362), pupil diameter(ICC = 0.137). Pentacam yielded higher values that were significant in five parameters including 3.47 µm for TCT, 4.29 µm for PCT, 10.03 mm3 for chamber volume,2.67 mm3 for cornea volume, and 1.49 mm for pupil diameter but there was only a statistically significant difference in cornea volume and pupil diameter (p-value < 0.001). However, in Pentacam only the chamber angle value was 6.44 mm3 lower than Sirius, with a statistically significant difference (p-value < 0.001). Although these two devices had some statistically different results, it seems that they have a good agreement and correlation in most parameters.

Effect of ocular biometric factors on corneal biomechanical properties.

PURPOSE: To evaluate the effects of ocular biometric variables on corneal biomechanical properties. METHODS: A total of 102 eyes of 102 participants were enrolled in this cross-sectional study. The axial length (AL) was determined by an IOL master 500 and measurements of corneal biomechanical properties were performed using Corvis ST, integrated with pentacam results. RESULTS: Aging and corneal steepening were associated with less corneal deformability and higher movement of the entire eye. Longer AL corresponded with greater deformability and lower corneal viscous damping properties and less whole eye movement (all P-values < 0.05). In contrast to mean keratometry (Mean K) and corneal diameter, anterior chamber depth (ACD) and AL have a significant effect on corneal biomechanical parameters. Corneal biomechanical index (CBI) was not significantly correlated with any of biometric parameters. Stress-strain index (SSI) was significantly correlated with age (r = 0.470), spherical equivalent (SE) (r = 0.537), AL (r = -0.534) and ACD (r = -0.316) (all P-values < 0.001). CONCLUSIONS: In normal individuals, several parameters such as age, ACD, AL and Mean K have a great impact on corneal biomechanical properties; thereby, these effects should be taken into account prior to interpretation of corneal biomechanics, particularly in older ages and eyes with longer AL and steeper cornea.

Evaluation of Histopathologic Findings and Safety of Intravitreal Ketamine Administration on Vitreoretinal Tissue in Rat Model: A Pilot Study.

Purpose: To evaluate the safety and histological findings of intravitreal injection of ketamine in rats. Methods: Each rat received a total volume of 0.1 ml of ketamine 0.01 mol/L (5 rats as ketamine group) or a total of 0.1 ml of normal saline 0.9% (5 rats as control group) under general anesthesia in a sterile condition. A histology assessment was performed 1 month after the intravitreal injection. Results: Lens opacity, necrosis, and atrophy of retinal layers and optic disc were not seen in five specimens in the ketamine group and five in the normal saline group. There was no inflammation in the vitreous, retinal layers, choroid, optic disc, and optic nerve in both groups. Conclusion: Intravitreal injection of ketamine in a special dose has no obvious adverse effect on diverse intraocular tissue.

Effects of Descemet Stripping Automated Endothelial Keratoplasty on Corneal Densitometry of Cases with Long-Standing Pseudophakic Bullous Keratopathy.

Purpose: To quantify the effects of Descemet stripping automated endothelial keratoplasty (DSAEK) on corneal clarity and densitometry of patients with long-standing pseudophakic bullous keratopathy (PBK) complicated with subepithelial fibrosis. Methods: Thirty-four eyes with PBK complicated with corneal edema for more than 6 months and subepithelial fibrosis were enrolled. All subjects underwent complete ophthalmic examination and corneal densitometry module of Pentacam HR, before and 1, 3, and 6 months after DSAEK. Results: Thirteen patients were excluded due to postoperative complications or missed to follow-up visits. Finally, twenty-one patients' data were analyzed. Corneal densitometry measures significantly decreased in all three layers (anterior, central, and posterior) 3 and 6 months after surgery compared to preoperative values; however, the differences did not reach statistical significance in the 1st month. Moreover, densitometry measurements were significantly lower at month 6 compared to month 1, but not at month 3 compared to month 1. Corneal densitometry of the anterior layer was significantly higher than central and posterior layers in 2 mm and 6 mm zones preoperatively and at all postoperative visits. Corneal light backscatter of each three layers was not statistically different between 0-2 mm and 2-6 mm in all pre- and postoperative visits. Conclusions: Corneal densitometry in cases of PBK begins to improve after DSAEK in different layers in a slow and continued trend which takes up to 6 months for an effect to be seen. Interestingly, this improvement is possible even in complicated corneas with long-standing edema. Hence, corneal densitometry can be used as an objective method for quantification of the outcome of DSAEK in complicated cases of PBK.

The effect of topical ketamine administration on the corneal epithelium repair.

The cornea is regarded as a sensitive organ to pain. Ketamine can effectively reduce postoperative neuropathic pain. We hypothesized that topical ketamine could mitigate postoperative corneal neuropathic pain. The aim of this study was to determine whether topical ketamine is safe for cornea and evaluate its effect on the repair procedure the damaged corneal tissue. Our study was performed on only the right eyes of 15 male rats. All animals underwent general anesthesia and the whole corneal epithelium was removed. All subjects were divided into two groups: group 1 (n = 8), one drop of ketamine, and group 2 (n = 7), one drop of 0.9% sodium chloride administered topically on the scraped cornea every 6 h for 7 days. The rats' s cornea was carefully monitored daily for the size of epithelial defects under a microscope and was photographed. On the eighth day, the eyes were sent for pathological examination. The eyes were examined for the amount of inflammation, neovascularization, keratinization, epithelial thickness and Descemet's membrane pathologies. The epithelial defect has healed completely on the sixth day in all rats in both groups. There was no significant difference in the speed of complete recovery between the two groups. No significant difference was observed between the two groups in terms of inflammation grade, neovascularization grade, and epithelial thickness. Our study showed that topical ketamine had no significant effect on corneal wound healing in a rat animal model and could be used safely for the management of postoperative chronic ocular pain.

Ray Tracing versus Thin-Lens Formulas for IOL Power Calculation Using Swept-Source Optical Coherence Tomography Biometry.

Purpose: To evaluate the ray tracing method's accuracy employing Okulix ray tracing software and thin-lens formulas to calculate intraocular lens (IOL) power using a swept-source optical coherence tomography (SS-OCT) biometer (OA2000). Methods: A total of 188 eyes from 180 patients were included in this study. An OA-2000 optical biometer was used to collect biometric data. The predicted postoperative refraction based on thin-lens formulas including SRK/T, Hoffer Q, Holladay 1, and Haigis formulas and the ray tracing method utilizing the OKULIX software was determined for each patient. To compare the accuracy of approaches, the prediction error and the absolute prediction error were determined. Results: The mean axial length (AL) was 23.66 mm (range: 19-35). In subgroup analysis based on AL, in all ranges of ALs the ray tracing method had the lowest mean absolute error (0.56), the lowest standard deviation (SD; 0.55), and the greatest proportion of patients within 1 diopter of predicted refraction (87.43%) and the lowest absolute prediction error compared to the other formulas (except to SRK/T) in the AL range between 22 and 24 mm (all P < 0.05). In addition, the OKULIX and Haigis formulas had the least variance (variability) in the prediction error in different ranges of AL. Conclusion: The ray tracing method had the lowest mean absolute error, the lowest standard deviation, and the greatest proportion of patients within 1 diopter of predicted refraction. So, the OKULIX software in combination with SS-OCT biometry (OA2000) performed on par with the third-generation and Haigis formulas, notwithstanding the potential for increased accuracy in the normal range and more consistent results in different ranges of AL.

Clinical outcomes of transepithelial photorefractive keratectomy with epithelial ablation targeting actual epithelial thickness vs default laser platform values.

PURPOSE: To investigate the clinical outcomes of transepithelial photorefractive keratectomy (tPRK) with actual epithelial thickness vs default software values. SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective controlled study. METHODS: Patients with refractive spherical error of -1.50 to -7.00 diopters (D) and refractive astigmatism up to 4.00 D were consecutively enrolled and divided into 2 groups: group 1 undergone tPRK with actual central and peripheral epithelial thickness input in right eyes, group 2 undergone tPRK with actual central and 10 mm higher peripheral epithelial thickness in right eyes. Left eyes in both groups underwent tPRK with default protocol. Outcome measures were induced refractive error, achieved optical zone (OZ), and wasted stromal tissue. RESULTS: 83 patients were included in this study. Mean ± SD of induced spherical equivalent was +0.15 ± 0.39 D and +0.01 ± 0.35 D in right and left eyes of group 1 (P = .01) and +0.04 ± 0.22 D and +0.03 ± 0.23 D in right and left eyes of group 2 (P = .75), respectively. There was no statistically significant difference between wasted tissue between right and left eyes in group 1 and group 2 (P = .77 and P = .49, respectively). OZ contraction was significantly higher in right compared with left eyes in group 1 (P = .05), but not in group 2 (P = .95). CONCLUSIONS: In tPRK, refractive outcomes, wasted tissue, and OZ contraction depend little on preexisting corneal epithelial thickness in corneas with normal range epithelial thickness. However, OZ contraction may be a concern in lower amount of ablations.

In vivo Confocal Microscopic Evaluation of Corneal Changes in Acute Endothelial Rejection.

PURPOSE: To evaluate the microstructural corneal changes during acute endothelial graft rejection and following treatment using in vivo confocal microscopy (IVCM). METHODS: Patients with a clinical diagnosis of severe acute endothelial graft rejection following penetrating keratoplasty were included in this study. IVCM was performed on the 1st day the patient presented with rejection signs and at the time of clinical resolution. RESULTS: Twenty-three patients were included in this study. Inflammatory cells appeared as dendritic cells (DCs) and less frequently, as non-DCs in basal epithelial and subbasal areas. Activated keratocytes (AKs) (type 1: large cells with visible cytoplasmic processes; type 2: elongated and spindle-shaped keratocytes) were visible in acute phase. Following resolution, type 1 AKs considerably reduced, but type 2 cells were more often persisted. Multiple types of keratic precipitates (KPs) were also visible in acute phase which resolved following resolution of rejection. CONCLUSIONS: Acute graft rejection was associated with an increase in the number of DCs, activation of keratocytes, and aggregation of various types of KPs. Inflammatory process subsided in almost all cases, but the IVCM changes did not return to normal early after clinical resolution of rejection.

Applications of Haptic Technology, Virtual Reality, and Artificial Intelligence in Medical Training During the COVID-19 Pandemic.

This paper examines how haptic technology, virtual reality, and artificial intelligence help to reduce the physical contact in medical training during the COVID-19 Pandemic. Notably, any mistake made by the trainees during the education process might lead to undesired complications for the patient. Therefore, training of the medical skills to the trainees have always been a challenging issue for the expert surgeons, and this is even more challenging in pandemics. The current method of surgery training needs the novice surgeons to attend some courses, watch some procedure, and conduct their initial operations under the direct supervision of an expert surgeon. Owing to the requirement of physical contact in this method of medical training, the involved people including the novice and expert surgeons confront a potential risk of infection to the virus. This survey paper reviews recent technological breakthroughs along with new areas in which assistive technologies might provide a viable solution to reduce the physical contact in the medical institutes during the COVID-19 pandemic and similar crises.

Ocular Neuropathic Pain: An Overview Focusing on Ocular Surface Pains.

OBJECTIVE: This paper reviews ocular pain with the main focus on ocular surface discomfort and dry eye pain. Anatomy, physiology, epidemiology, assessment, and treatment are discussed in this paper. METHODS: A PubMed search was conducted for studies published from 2000 to 2019 on the anatomy, pathophysiology, epidemiology, assessment, and treatment of ocular pain. Reviews, meta-analyses, and randomized clinical trials were included. Inclusion criteria focused on ocular surface discomfort, dry eye pain and neuropathic pain. RESULTS: A total of 112 articles were found through searches, 45 of which were selected and studied in this review. DISCUSSION: Pain in general can be acute or chronic. Acute pain is usually a physiologic response to a serious damage to the tissues and alleviates with pain relief treatments. Chronic pain is defined as the persistence of pain for more than three months. From another point of view, pain has been classified into either nociceptive or neuropathic. Nociceptive pain is a physiologic response to a noxious stimulus. Both central and peripheral nervous systems can be involved in the development of a neuropathic pain, which is characterized by positive or negative sensory signs, a pain perceived disproportionate to a noxious stimulus, and/or not responsive to analgesics. Chronic pain usually has a neuropathic component. Ocular surface pain is a well-known complaint after any corneal surgery. This is mainly due to abnormal regeneration of damaged corneal nerve endings and abnormal connections with adjacent nerve endings which produce spontaneous activity. Tear hyperosmolarity and the resultant ocular surface inflammation can also trigger voluntary activity of corneal nerve endings. Referral pain to the first and second division of the trigeminal nerve has been reported. Interference with vision and even sleep, which is out of proportion to the examination are among patients' complaints. All of these elements proposed the new concept of ocular neuropathic pain syndrome. The first step in conventional evaluation of ocular discomfort is search for tear insufficiency. Pathologies of lid and blinking as well as conjunctival irregularities should be addressed. Anti-inflammatory agents and, in resistant cases, systemic neuromodulators are shown to be helpful. Education on behavioral changes and reassurance are essential steps. Considering the neuropathic origin for the ocular pain, treatment modalities used for such pain in other parts of the body can be considered for this syndrome.

Longitudinal evaluation of posterior corneal power by anterior segment optical coherence tomography 18 months following photorefractive keratectomy.

PURPOSE: To investigate the change in anterior, posterior, and net corneal power more than 18 months after photorefractive keratectomy (PRK) by RTVue anterior segment optical coherence tomography (OCT). SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective observational study. METHODS: PRK was performed using Technolas TENEO 317 laser platform. Anterior, posterior, and net corneal power was measured by the RTVue-XR anterior segment OCT system with the Pachymetry + Cpwr scan pattern at baseline and months 1, 3, 6, 12, 18, and more than 18 (up to 27) after PRK. RESULTS: Three hundred twenty-six eyes of 163 patients (61 men [37.4%], 102 women [62.6%]; mean age 29.71 years; range 18.5 to 46.5 years) were enrolled in this study. Mean preoperative spherical equivalent was -3.15 ± 1.50 diopter (D) (range -8.37 to -0.62 D). The mean change in net corneal power was 3.052 D, 3.281 D, 3.324 D, 3.114 D, 3.446 D, and 3.972 D at months 1, 3, 6, 12, 18, and more than 18 postoperatively compared with baseline, respectively (P < .001 for all comparisons). The mean change in posterior corneal power at postoperative visits compared with baseline was not statistically significant (P > .1) except for 1 month postoperatively, which increased by 0.13 D (P < .001). Changes in posterior corneal power were not correlated with any of the preoperative clinical and Scheimpflug variables. CONCLUSIONS: Posterior corneal power did not change for more than 18 months after PRK, except for an early small increase at 1 month postoperatively.

Correlation between Corneal Topographic Patterns and Refractive Status of the Eye in an Adult Iranian Population: Tehran Study.

PURPOSE: To evaluate the corneal topographic patterns in an adult Iranian population and investigate its correlation with the refractive status of the eye. METHODS: In a cross-sectional study named "Tehran Study," 1023 samples were selected by the cluster sampling method from the downtown area of Tehran. Eight hundred and forty-nine adults aged over 15 years participated. All selected participants were refracted and underwent topography imaging. RESULTS: The patients' ages ranged from 15 to 91 years with a mean of 40.33 ± 16 years. The most frequent topographic patterns were symmetric bowtie (SB) (34%), SB with inferior steepening (SB-IS) (14.1%), and round (10.5%). The orders changed in categorization by refractive status: The most frequent pattern in all subgroups (emmetropia, myopia, and hyperopia) was SB with frequencies 32.7%, 35.8%, and 22.5%, respectively. Although the second order was asymmetric bowtie (AB) with AB-IS in the emmetropic and myopic subgroups, in the hyperopic subgroup, round pattern had the second place. The third place was different in all groups. The rarest patterns in the whole were SB with skewed radial axis (SRAX) and AB with SRAX. The first prevalent topographic pattern was SB in all age groups and in both genders. The prevalence of round pattern, irregular pattern, and SRAX significantly increased in older ages, and the prevalence of SB decreased in older ages. The first observed prevalent pattern was SB in both sexes, but the second most prevalent pattern was AB-IS and round in females and males, respectively. CONCLUSIONS: Corneal topographic pattern might be related to the refractive status of the eye. The information about normal topographic patterns provides a reference for comparison with diseased corneas.

Optic Nerve Head Morphology in Nonarteritic Anterior Ischemic Optic Neuropathy Compared to Open-Angle Glaucoma.

PURPOSE: To compare optic nerve head (ONH) morphology of optic nerve atrophy between eyes with primary open-angle glaucoma (POAG) and eyes with a history of nonarteritic anterior ischemic optic atrophy (NAION) using enhanced depth imaging (EDI) with spectral-domain optical coherence tomography (SD-OCT). METHODS: In this cross-sectional study, 121 eyes of 91 patients consisted of moderate to severe POAG (n = 32 eyes), visual field mean deviation-matched NAION (n = 30 eyes) and their fellow eyes (n = 30 eyes), and healthy controls (n = 29). The optic discs were scanned using SD-OCT and measurements were obtained using HEYEX software 6.0. Lamina cribrosa (LC) thickness and anterior lamina cribrosa depth (ALD) at three scans (midsuperior, central, and midinferior) were determined and compared. In addition, prelaminar tissue thickness was measured at three points of a single central scan. RESULTS: There was no significant difference in the visual field mean deviation (MD) between the NAION and POAG groups (P > 0.99), but both groups had a significantly worse MD than the healthy group (P < 0.001). The NAION and POAG groups had similar peripapillary retinal nerve fiber layer (pRNFL) thickness (P < 0.99). Eyes with POAG had greater ALD and thinner LC than control eyes and NAION eyes in all regions of the ONH (P < 0.001 for both). There was a marked prelaminar tissue thinning in POAG eyes compared to control and NAION eyes (P < 0.001). Lamina cribrosa thickness and ALD of NAION eyes were not different from their fellow eyes and control eyes. Although prelaminar thickness was thinner in NAION eyes compared to their fellow eyes (P = 0.005), it was thicker than in control eyes (P < 0.001). CONCLUSIONS: Despite profound thinning and posterior displacement of LC in POAG, the thickness and position of LC in NAION eyes are similar to those seen in healthy control and their fellow eyes.

Comparison of the Pattern of Macular Ganglion Cell-Inner Plexiform Layer Defect Between Ischemic Optic Neuropathy and Open-Angle Glaucoma.

PURPOSE: To compare the pattern of macular ganglion cell plus inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thickness changes in moderate to severe primary open-angle glaucoma (POAG) with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography (OCT) auto-segmentation. METHODS: A total of 138 eyes (42 eyes with chronic unilateral NAION and their 42 unaffected fellow eyes, 32 eyes of 32 moderate to severe glaucoma patients, and 22 eyes of 22 healthy normal subjects) underwent neuro-ophthalmologic examinations and spectral-domain OCT in a cross-sectional study at a single academic institution. GCIPL and total retinal thicknesses were obtained from 20° by 20° cube scans of the macula centered around the fovea. The scanned region was divided into two concentric regions (inner and outer, with diameters of 3 and 6 mm, respectively) and eight sectors (four sectors in each of the inner and outer regions). Peripapillary RNFL thickness was also measured. RESULTS: Peripapillary RNFL, total macula, and GCIPL were significantly thinner in NAION and POAG eyes compared to unaffected fellow eyes of NAION and to age-matched healthy control eyes in all eight sectors (P < 0.001). There was no significant difference in peripapillary RNFL, total macula, and outer region GCIPL thicknesses between the affected eyes of the patients with NAION and glaucoma patients. However, the inner region GCIPL was significantly thinner in NAION eyes compared to POAG eyes after adjusting for age, sex, and mean deviation of the visual field (P = 0.001). Also, the GCIPL sector thicknesses were more strongly correlated with visual acuity than were the macular sectors in all patients (most sectors P ≤ 0.001). CONCLUSIONS: Patients with NAION show differences in the tissue damage with greater loss of parafoveal GCIPL tissue thickness compared to patients with POAG.

Evaluation of Lamina Cribrosa and Choroid in Nonglaucomatous Patients With Pseudoexfoliation Syndrome Using Spectral-Domain Optical Coherence Tomography.

PURPOSE: To evaluate the lamina cribrosa (LC) and peripapillary choroid in patients with pseudoexfoliation syndrome (PXS). METHODS: In this cross-sectional study, one eye each of 32 nonglaucomatous PXS cases and 29 healthy volunteers were enrolled. The optic discs were scanned using enhanced depth imaging spectral-domain optical coherence tomography, and measurements were obtained using HEYEX software 6.0. LC and other related variables at three areas (mid-superior, center, and mid-inferior) and peripapillary choroidal thickness were determined. Linear mixed modeling was used to adjust the variables. RESULTS: After adjustment for age, sex, and axial length, there was no significant difference between the two groups in peripapillary choroidal thickness or in retinal nerve fiber layer thickness. The LC was significantly thinner in all three areas in the PXS group when compared with the control group, even after adjustment. Although no significant difference in central laminar depth was observed between the two groups (P = 0.74), the superior and inferior laminar depth were significantly deeper in the PXS group when compared with the control group (P = 0.04 and P = 0.006, respectively). Although there was a significant negative association between age and central choroidal thickness in the control group (ß = -2.820, P = 0.02), this correlation was not significant in the PXS group. CONCLUSIONS: We found that LC is significantly thinner in all three areas of the optic nerve head in nonglaucomatous PXS patients than in controls. Although no significant difference in peripapillary choroidal thickness was observed between the two groups, peripheral posterior displacement of LC in nonglaucomatous PXS eyes was noted.

Retinal Ganglion Cell Loss Precedes Retinal Nerve Fiber Thinning in Nonarteritic Anterior Ischemic Optic Neuropathy.

BACKGROUND: Loss of retinal ganglion cell-inner plexiform layer (GCIPL) thickness has been shown in different optic neuropathies. In this study, we evaluated the capability of GCIPL analysis by optical coherence tomography (OCT) to detect early neuronal loss during the time course of nonarteritic anterior ischemic optic neuropathy (NAION). METHODS: Twenty-four patients with unilateral NAION participated in this prospective, comparative study. Affected and unaffected eyes underwent spectral domain OCT measurement of the retinal nerve fiber layer (RNFL), total macula, and GCIPL thicknesses. These measurements were recorded in the acute phase (within 7 days) and at 1, 3, and 6 months. RESULTS: At the initial presentation and 1, 3, and 6 months, the mean RNFL thickness in the NAION eyes was 236.5 µm ± 74.2, 157.1 µm ± 45.7, 61.4 µm ± 6.1, and 55.0 µm ± 19.5, respectively. Similar to RNFL, thinning of the mean total macular thickness in inner and outer rings started after 3 months and thicknesses decreased to 307.7 µm ± 15.3 and 273.1 µm ± 21.2 after 3 months and to 309.1 µm ± 15.0 and 273.4 µm ± 13.8 after 6 months, compared with unaffected contralateral eyes, respectively (all P < 0.0001). Thinning of the GCIPL was first evident in the affected NAION eyes at 1 month, and the mean inner and outer GCIPL thicknesses were 62.8 µm ± 14.6 and 53.9 µm ± 7.2 at 1 month in the NAION eyes compared with unaffected eyes (P < 0.001). After 3 and 6 months, the inner and outer GCIPL thicknesses were 51.1 µm ± 8.1 and 47.4 µm ± 5.31, and 50.6 µm ± 11.5 and 47.9 µm ± 5.6, respectively. CONCLUSIONS: Thinning of the GCIPL is first detectable at 1 month after NAION and persists for 3 months. GCIPL thinning occurs before RFNL thinning in NAION.