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.

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.

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.

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 1^st 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.

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.

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.

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.

Peripapillary choroidal thickness in nonarteritic anterior ischemic optic neuropathy

PURPOSE

To compare peripapillary choroidal thickness, macular thickness, and peripapillary retinal nerve fiber layer (RNFL) thickness between the affected eyes of patients with nonarteritic anterior ischemic optic neuropathy (NAION) and their unaffected eyes and the eyes of normal control subjects.

METHODS

Thirty-two eyes with NAION, 25 unaffected fellow eyes, and 25 normal control subjects met the inclusion criteria in this prospective comparative study at a single academic institution. Optic disc area, macular thickness, and RNFL thickness were evaluated at last follow up time using spectral-domain optical coherence tomography (OCT). Enhanced depth imaging OCT was obtained to evaluate peripapillary choroidal thickness.

RESULTS

Mean follow up time was 4.9 ±0.8 months and all data was collected from the last follow up. The mean optic disc area in NAION eyes and their unaffected fellow eyes were significantly smaller than normal control disc area measurements (P<0.001). Average PCT and all regional values were significantly greater in the NAION eyes and unaffected fellow eyes than in the control eyes (P=0.01). In all subjects, optic disc area was correlated with average PCT (r = -0.33, P = 0.002). In addition, RNFL thickness and macular thickness values were significantly lesser in the NAION eyes than in the unaffected fellow eyes and control eyes.

CONCLUSIONS

PCT is thicker in NAION eyes and unaffected fellow eyes than control eyes. Thick peripapillary choroid might contribute to the development of NAION.

Microbiologic spectrum of acute and chronic dacryocystitis

AIM

To report the microbiological spectrum of acute and chronic dacrocystitis.

METHODS

Retrospective study on 100 patients who presented to the ophthalmic plastic clinic of a tertiary eye care center from May 2011 and April 2013 with acute and chronic dacryocystitis was reviewed for demographic and microbiological profile. The culture results and organisms isolated were recorded.

RESULTS

Sixty patients had acute onset and the remaining 40 patients had chronic onset dacryocystitis. The female to male ratio was 1.78. The mean age of patients was 44y. Gram-positive organisms were the most commonly isolated accounting for 54%, and the commonest species isolated was S. aureus in 26%. Percentage of gram positive cultures was higher in chronic dacryocystitis than acute ones (82% vs 48% of positive cultures; P=0.003). Also in culture positive acute dacryocystitis, gram negative species were found in 52% of eyes but only in 18% of chronic dacryocystitis.

CONCLUSION

Gram negative bacteria, culture negative samples, unusual and more virulent organisms are more common in acute dacryocystitis than chronic ones. The results of this study have significant bearing on the treatment of patients with dacrocystitis.

Quantification of peripapillary total retinal volume in pseudopapilledema and mild papilledema using spectral-domain optical coherence tomography

PURPOSE

To distinguish differences in retinal nerve fiber layer (RNFL) thickness and peripapillary total retinal volume between eyes with papilledema, pseudopapilledema, and normal findings.

DESIGN

Cohort study.

METHODS

Forty-two eyes with mild papilledema, 37 eyes with congenitally elevated optic disc (pseudopapilledema), and 34 normal eyes met the inclusion criteria at 1 academic institution (in Iran) and underwent neuro-ophthalmic examination. Spectral-domain optical coherence tomography scans surrounding the optic disc were performed in each eye of patients and subjects. Main outcome measures were mean RNFL thickness and peripapillary total retinal volume measurements (inner and outer ring volumes) that were compared between groups, using the generalized estimating equation approach. Area under receiver operating characteristic curves were also calculated.

RESULTS

A statistically significant difference was found in mean RNFL thickness between both groups of patients with papilledema and pseudopapilledema and normal subjects. Average inner peripapillary total retinal volume in the papilledema, pseudopapilledema, and control groups were 1.95 ± 0.24 mm(3), 1.81 ± 0.23 mm(3), and 1.06 ± 0.10 mm(3), respectively. Average outer peripapillary total retinal volume in the papilledema and pseudopapilledema groups were 2.68 ± 0.49 mm(3) and 2.03 ± 0.24 mm(3), respectively (P < .001). However, the outer ring peripapillary total retinal volume was not different between pseudopapilledema and normal (1.90 ± 0.11 mm(3)) eyes (P = .17). Area under the curve to discriminate pseudopapilledema vs papilledema eyes for average RNFL thickness and inner and outer peripapillary total retinal volumes was 0.82, 0.68, and 0.88, respectively.

CONCLUSION

Outer peripapillary total retinal ring volumes might be useful in differentiating papilledema from pseudopapilledema.