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Objective: Postoperative visual loss resulting from posterior ischemic optic neuropathy (PION) after spinal surgery is rare but devastating. A potential risk factor is prolonged spinal surgery in the prone position. We hypothesized that if this risk factor is linked to PION, the retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) should decrease post-surgery. Materials and Methods: The prospective cohort study was conducted in patients undergoing spinal surgery in the prone position. The RNFL and GCIPL thickness by optical coherence tomography before and after spinal surgery (6-week, 3-month post-operative) were analyzed. Results: Nineteen patients (38 eyes) completed the study with three follow-up timepoints. The mean age was 53.78+/-12.71 years. No significant changes were observed in the RNFL thickness and macular ganglion cell-inner plexiform layer changes at the 6 weeks and 3 months follow-ups, except for the RNFL at the inferior quadrant at 6 weeks follow-up. There were also no patients who experienced visual loss. Conclusion: A transient decrease in RNFL thickness in the inferior quadrant was observed at the 6-week postoperative follow-up after spinal surgery. The prone position during surgery may be an intraoperative factor associated with the development of perioperative PION in patients undergoing spinal procedures. [ABSTRACT FROM AUTHOR]

The prone position reduces mortality in severe cases of COVID-19 with acute respiratory distress syndrome. However, visual loss and changes to the peripapillary retinal nerve fiber layer (p-RNFL) and the macular ganglion cell layer and inner plexiform layer (m-GCIPL) have occurred in patients undergoing surgery in the prone position. Moreover, COVID-19-related eye problems have been reported. This study compared the p-RNFL and m-GCIPL thicknesses of COVID-19 patients who were placed in the prone position with patients who were not. This prospective longitudinal and case-control study investigated 15 COVID-19 patients placed in the prone position (the "Prone Group"), 23 COVID-19 patients not in the prone position (the "Non-Prone Group"), and 23 healthy, non-COVID individuals without ocular disease or systemic conditions (the "Control Group"). The p-RNFL and m-GCIPL thicknesses of the COVID-19 patients were measured at 1, 3, and 6 months and compared within and between groups. The result showed that the Prone and Non-Prone Groups had no significant differences in their p-RNFL thicknesses at the 3 follow-ups. However, the m-GCIPL analysis revealed significant differences in the inferior sector of the Non-Prone Group between months 1 and 3 (mean difference, 0.74 μm; P = 0.009). The p-RNFL analysis showed a significantly greater thickness at 6 months for the superior sector of the Non-Prone Group (131.61 ± 12.08 μm) than for the Prone Group (118.87 ± 18.21 μm; P = 0.039). The m-GCIPL analysis revealed that the inferior sector was significantly thinner in the Non-Prone Group than in the Control Group (at 1 month 80.57 ± 4.60 versus 83.87 ± 5.43 μm; P = 0.031 and at 6 months 80.48 ± 3.96 versus 83.87 ± 5.43 μm; P = 0.044). In conclusion, the prone position in COVID-19 patients can lead to early loss of p-RNFL thickness due to rising intraocular pressure, which is independent of the timing of prone positioning. Consequently, there is no increase in COVID-19 patients' morbidity burden. [ABSTRACT FROM AUTHOR]

Background: Optic neuritis (ON) is one of the common manifestations both in neuromyelitis-optica spectrum disorders (NMOSD) and in multiple sclerosis (MS). Objectives: The objective of this paper is to compare clinical presentations, laboratories and imaging findings in ON associated with MS and NMOSD. Methods: A retrospective chart review was performed in patients presenting with ON in 59 NMOSD patients with 72 eyes' involvement and 163 ON attacks, and 20 MS patients with 23 eyes' involvement and 36 ON attacks. Results: ON-NMOSD patients had recurrent ON more often and tended to have simultaneous bilateral ON involvement at their first ON attack. Individuals with ON-NMOSD revealed worse visual acuity at first ON attacks and also had poorer long-term visual outcome than those with ON-MS, with nearly half of ON-NMOSD patients still having LogMAR visual acuity ≥1 at their last follow-up (p=0.035). Significant thinner average retinal nerve fiber layer thickness was found in the ON-NMOSD group. We found no significant differences in segmentation location of the optic nerve lesions and the length of involvement between the two groups. Conclusions: It was difficult to completely differentiate ON-NMOSD from ON-MS. ON-NMOSD patients, however, tended to have simultaneous bilateral ON involvement and poorer long-term visual outcome than individuals with ON-MS. [ABSTRACT FROM AUTHOR]

Study Objectives: To assess the effect of continuous positive airway pressure (CPAP) therapy on intraocular pressure in Obstructive sleep apnea (OSA) patients., Methods: The search was performed in Ovid Medline and Embase database then followed by a manual bibliography search. Abstract search and screening were independently performed followed by eligible full-text versions reviewed. Then disagreements were discussed in a group., Results: This systematic review and meta-analysis considered 15 studies with 495 participants. The pooled mean intraocular pressure after CPAP therapy shows no significant difference compared to the baseline (MD, 0.58 mmHg; 95% CI, -0.33 to 1.19). Subgroup analysis shows significantly higher intraocular pressure after in-lab PAP titration and after long-term CPAP used (MD, 4.28 mmHg; 95% CI, 0.91 to 7.66; MD, 0.45 mmHg; 95% CI, 0.07 to 0.83; respectively). Ocular perfusion pressure was also significantly decreased after CPAP therapy. (MD, -2.15 mmHg; 95% CI, -3.50 to -0.80). The pooled data showed no significant difference in RNFL thickness and macular layer thickness., Conclusions: After long-term treatments CPAP therapy, there is a significant increase in intraocular pressure in patients with OSA and a decrease in ocular perfusion pressure but did not show a significant difference in other ophthalmologic parameters. For this reason, CPAP usage in glaucoma patients necessitates to be done cautiously., Systematic Review Registration: This systematic review protocol was registered with PROSPERO (registration number CRD42022370734)., (© 2025 American Academy of Sleep Medicine.)

Aim: To compare the thickness of the peripapillary retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) among patients with various forms of optic neuritis (ON) and to identify whether any particular parameters or their thinning pattern can be used to distinguish the type of ON., Methods: This prospective study was conducted at the Department of Ophthalmology, Faculty of Medicine, Siriraj Hospital, Thailand, between January, 2015 and December, 2016. We enlisted patients over 18 years of age with history of ON and categorized patients into 4 groups: 1) aquaporin 4 antibodies (AQP4-IgG) positive; 2) multiple sclerosis (MS); 3) myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) positive; 4) idiopathic-ON patients. Healthy controls were also included during the same study period. All patients underwent complete ophthalmological examination and spectral domain optical coherence tomography (OCT) imaging to analyze RNFL and GCIPL thickness after at least 3mo since the last episode of acute ON. The generalized estimating equation (GEE) models were used to compare the data amongst ON groups., Results: Among 87 previous ON eyes from 57 patients (43 AQP4-IgG+ON, 17 MS-ON, 8 MOG-IgG+ON, and 19 idiopathic-ON), mean logMAR visual acuity of AQP4-IgG+ON, MS-ON, MOG-IgG+ON, and idiopathic-ON groups was 0.76±0.88, 0.12±0.25, 0.39±0.31, and 0.75±1.08, respectively. Average, superior, and inferior RNFL were significantly reduced in AQP4-IgG+ON, MOG-IgG+ON and idiopathic-ON eyes, relative to those of MS-ON. Differences were not statistically significant for RNFL or GCIPL between the AQP4-IgG+ON and MOG-IgG+ON groups, whereas visual acuity in MOG-IgG+ON was slightly, but not significantly, better (0.39 vs 0.76). Although RNFL thickness in MOG-IgG+ON was significantly reduced as compared to MS-ON, mean visual acuity and GCIPL were not different., Conclusion: Thinning of superior and inferior quadrants of RNFL are more commonly seen in MOG-IgG+ON and AQP4-IgG+ON. Long term visual acuity in MOG-IgG+ON is often better than AQP4-IgG+ON, whereas the structural change from OCT is comparable.

Aim: To compare the retinal nerve fiber layer (RNFL) thickness in the morning and evening in Thai patients with varying degrees of obstructive sleep apnea/hypopnea syndrome (OSAHS)., Methods: In this cross-sectional study, potential OSAHS patients at Siriraj Hospital underwent polysomnography to determine the severity of OSAHS and an eye examination (including best corrected visual acuity, slit-lamp examination, and Goldmann applanation tonometry). RNFL thickness was recorded once in the morning and once in the evening, using spectral domain optical coherence tomography. Thickness was expressed as an average and given for each quadrant. Patients with ocular or systemic diseases that might affect RNFL thickness were excluded., Results: Forty-one eyes of 41 patients were classified into 4 OSAHS groups. The average and mean RNFL thickness in most of the four quadrants of the severe OSAHS group trended toward being less than those in the comparable quadrants of the other groups in both the morning and evening. In the moderate OSAHS group, the average RNFL thickness and temporal and superior quadrant thickness in the morning were significantly higher than in the evening (P=0.01, P=0.01, and P=0.03, respectively). In the severe OSAHS group, the inferior quadrant thickness in the morning was significantly higher than in the evening (P=0.03)., Conclusion: The RNFL thickness in the morning was higher than in the evening in moderate OSAHS.

Background: The retinal pathophysiology of methanol intoxication is that formate inhibits retinal mitochondrial function and increases oxidative stress., Objective: To investigate the effect of coenzyme Q10 and curcumin on chronic methanol intoxication causing retinopathy in rats., Material and Method: The authors designed an experimental study of chronic methanol intoxication in rats depleted of folate with methotrexate. The studied group received methanol (2 mg/kg body weight in saline by intraperitoneal injection) and methotrexate (0.1 mg/kg body weight in saline by subcutaneous injection) every other day for ten weeks to induce chronic methanol intoxication, while another group received saline as vehicle and served as control group. The studied rats were confirmed to develop significant retinopathy after 10 weeks and then assigned to three treatment arms: either corn oil (as control) or coenzyme Q10 (20 mg/kg/day) or Curcuma longa extract (2.5 mg/kg/day) for four weeks. Eyes were enucleated and the retinal tissue was prepared for histological examination. The sections were evaluated by an experienced pathologist and blinded to the experimental conditions., Results: Histological analysis revealed that animals treated with both methanol and methotrexate showed vacuolation of photoreceptor inner segment and disaggregation of cells in the inner and outer nuclear layers of the retina compared to a normal histological appearance in control animals. The retinal histology in the experimental animals with administration of Coenzyme Q10 or Curcuma longa extract appeared essentially normal and this was not found in the experimental animals which received corn oil., Conclusion: Coenzyme Q10 and curcumin administration improves retinal histology by reversing the pathological changes due to chronic methanol and establish a morphologically normal retina.

Ninety-six patients with ocular myasthenia gravis (OMG) seen at Siriraj Hospital during 1994 to 2004 were retrospectively reviewed. There were 59 female (61.5%) and 37 (38.5%) male patients with mean ages of 39.5 and 33.8 years, respectively Patients presented with initial symptoms of only ptosis in 46.9%, only diplopia in 13.5% and both ptosis and diplopia in 39.6%. However, diplopia alone is uncommon in childhood OMG. Fifteen percent developed systemic symptoms within two years of diagnosis. Thyroid function test was abnormal in 27.5% of investigated patients. Most abnormalities were hyperthyroidism. Thymoma associated with OMG is a rare condition. Most purely OMG patients can control the disease by pyridostigmine, prednisolone or immunosuppressive drugs.

Objective: To study the incidence of dry eye in Sjögren-like syndrome, graft-versus-host disease (GVHD) in hematological patients undergoing bone marrow transplantation (BMT)., Material and Method: Prospective, cross-sectional study in twenty-six patients that were planned for BMT (group I). Twenty-nine patients undergoing BMT before study were classified as group II no GVHD (9), and group III with GVHD (20). Thirty-two normal subjects were controls. All subjects were examined by slit lamp biomicroscopy and had their tear samples analyzed about tear osmolarity. They were also evaluated for aqueous tear production by phenol red thread test, Schirmer test without anesthesia, tear film stability by tear break-up time (TBUT), and rose bengal staining 2 weeks before BMT (for group I) as well as 6 weeks, 3 months, and 6 months after BMT. The patients with GVHD were followed up 1 month later. Main outcome measures were amount of tear production, tear film stability, and dry eye symptoms., Results: Average aqueous tear production in group III was less than control and group II (p < 0.001). Mean TBUT in group III was faster than control (p < 0.001) and group I before BMT (p = 0.001). Mean score of rose bengal staining in group III was more than control and group I before BMT (p < 0.001). Keratoconjunctivitis sicca and red eye developed in 27.5%, and 20% of group III, with incidence of dry eye by Schirmer test without anesthesia (67.5%). This compares with group II having incidence of dry eye of 16.7%. However, 42.3% of group I before BMT had dry eye compared with 9.4% in the controls (p < 0.001)., Conclusion: Trend of dry eye in patients with BMT and GVHD were higher than no-GVHD group. Doctors should be aware of ocular symptoms and signs of dry eye in patients with BMT and follow-up for proper management.

Objective: Describe the clinical characteristics of pediatric optic neuritis., Material and Method: Retrospective observational case series was performed on patients < or = 12 years of age with optic neuritis at Childrens Hospital Los Angeles., Results: Thirty-one patients (48 eyes) were identified. Mean follow-up was 2.7 years. There were 17 preadolescents (< 10-years-old) in group I, and 14 adolescents (10--12-years-old) in group II. Females comprised 59% of group I, and 71% of group II. Bilateral cases comprised 65% from group I, and 43% from group II. Five patients from group I had acute disseminated encephalomyelitis (ADEM). Two patients from group II had multiple sclerosis (MS). No other patients developed MS. There was no difference in initial or final vision for the eyes with or without steroid treatment., Conclusion: Pediatric optic neuritis has no gender or racial predilection, is usually bilateral, and is associated with ADEM rather than MS.

Objective: To compare the visual evoked potentials (VEP) in patients with acute optic neuritis, recurrent optic neuritis, and optic neuritis with multiple sclerosis., Material and Method: The authors retrospectively reviewed VEP latency records of the patients with optic neuritis in Siriraj Hospital from 1995 to 2005 and divided them into three groups, acute optic neuritis, recurrent optic neuritis, and optic neuritis with multiple sclerosis (ON/MS). The patients with non-recordable VEP in the analysis were excluded. Comparison of the mean latency of the VEP in affected eyes among the three groups was statistically analyzed by a nonparametric independent sample test., Results: Twenty-two patients with acute optic neuritis, 8 patients with recurrent optic neuritis, and 22 patients with ON/MS participated in this study. The mean age among the three groups was not statistically significant. The median value of the latency of flash VEP (fVEP) and pattern reversal VEP (PRVEP) in the acute optic neuritis group was shorter than that of the recurrent optic neuritis group, and statistically significant (fVEP p = 0.012; PRVEP, p = 0.004). The median value of the latency of PRVEP in the acute optic neuritis group was shorter than that of the ON/MS group, and statistically significant (PRVEP p = 0.002). The median value of the latency of both fVEP and PRVEP in the recurrent optic neuritis group and ON/MS group were delayed with no statistical significance (fVEP p = 0.458; PRVEP, p = 0.403)., Conclusion: The VEP can be used to demonstrate the demyelinating mechanism of optic neuritis and optic neuritis with multiple sclerosis, but cannot determine the susceptibility of the patients with acute ON to become MS. The significantly delayed latency of VEP in recurrent optic neuritis is possibly caused by severe damage of the optic nerve conduction from recurrent attacks.

Traumatic chiasmal syndrome is a rare complication of closed head trauma. It often presents as bitemporal hemianopia and may be associated with other neurological signs. The authors report a case of a 47-year-old man who had sustained severe frontal head trauma from a motor vehicle accident that caused multiple cranial fractures and prolonged loss of consciousness. He was subsequently diagnosed with traumatic chiasmal syndrome. Tangent field testing revealed bitemporal hemianopias with some macular sparing. Macular sparing was not found on the central 30-2 pattern of Humphrey visual field test.

Objective: To determine clinical characteristics of patients with optic neuritis and visual outcome after intravenous methylprednisolone treatment., Method: A total of 81 patients with optic neuritis were reviewed retrospectively with regard to their clinical characteristics by dividing into two groups as follows: group I had isolated optic neuritis and group II had optic neuritis with demyelinative disease. The visual outcome in these patients before and after intravenous methylprednisolone treatment was analyzed., Results: Of 81 patients with optic neuritis, 63 patients (77.8%) had isolated optic neuritis and 18 (22.2%) patients were optic neuritis with demyelinative disease. The ages of the patients ranged from 16 to 59 years (mean = 35.3 years) in patients with isolated optic neuritis and from 16 to 73 years of age (mean = 35.8 years) in patients with optic neuritis with demyelinative disease. After treatment, 45 patients (52 eyes) with isolated optic neuritis and 14 patients (25 eyes) with optic neuritis with demyelinative disease who were followed-up for more than 10 days were studied. After treatment, 60 per cent of the isolated optic neuritis patients and 24 per cent of the optic neuritis patients with demyelinative disease had a visual acuity of 6/12 or better respectively. The isolated optic neuritis who had an onset interval to treatment of less than 8 days had a visual acuity better than 6/9 in 75 per cent., Conclusion: The final visual outcome in patients with isolated optic neuritis who received earlier treatment was better than those who received treatment later.

Purpose: To determine whether the improvement in visual acuity obtained when using high dose dexamethasone in the treatment of traumatic optic neuropathy was comparable to that of megadose methylprednisolone., Method: A total of forty-four patients with traumatic optic neuropathy were prospectively randomized and selected to receive intravenous high dose dexamethasone or megadose methylprednisolone within 2 weeks of injury. Age, gender, cause of injury, interval from injury to treatment, initial, post-pulse, and final visual acuity were analysed statistically to compare the dexamethasone and methylprednisolone groups., Results: The mean interval to treatment was not significantly different (p=0.28) for the dexamethasone group at 5.5 days compared to the methylprednisolone group at 4.1 days. Visual improvement of at least two lines of the Snellen chart or two levels of unmeasured visual acuity was shown in 9 patients (37.5%) of the dexamethasone group and 10 patients (50%) of the methylprednisolone group. There was no statistically significant difference between the initial and post-pulse visual acuity (p=1.0) and the initial and final visual outcome (p=0.60) in the dexamethasone group compared with the methylprednisolone group., Conclusion: There was no significant difference in the visual acuity obtained after treatment with intravenous dexamethasone or methylprednisolone for traumatic optic neuropathy.