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Objective: To evaluate the success rates of different treatment modalities, identify prognostic factors associated with treatment outcomes and factors influencing disease progression in keratoconus patients. Materials and Methods: A retrospective cohort study of keratoconus patients at Siriraj Hospital during January 2013 to December 2023 was done. Patient characteristics, symptoms and signs related to keratoconus, outcomes of corneal topography, treatment modalities, and best-corrected visual acuity (BCVA) before and after treatment were recorded. Treatment outcome was defined as a “success” when the BCVA post-treatment was equal to or better than 6/12. Progression of keratoconus was based on the Belin ABCD progression criteria. Results: Total 119 patients (231 eyes) were analyzed. The mean age at diagnosis was 28.0 ± 9.5 years. Two hundred and sixteen eyes (93.5%) were clinical keratoconus. The overall success rate of all treatment modalities was 87.4%. Contact lenses were the most frequent treatment modality (147 eyes, 72.4%) with the highest success rate (90.5%). A worse initial BCVA, high keratometric reading and thinner cornea were risk factors for treatment failure in this group. Of 133 eyes disease progression could be evaluated (median follow-up time; 33 months) and 58 eyes (43.6%) met criteria for disease progression (median survival time; 8.8 years). No significant factors were found to be associated with disease progression. Conclusion: Success rate in keratoconus treatment at Siriraj Hospital was 87.4%. Contact lenses were most frequently applied 72.4%. Factors associated with treatment failure were found in this group but for disease progression remained unclear due to limitations of the study.

Objective: To quantify rate of post-lens tear thickness change under scleral contact lenses in keratoconus patients and normal cornea volunteers. Materials and Methods: We conducted a prospective observational study where semi-scleral lenses were fitted to 20 eyes (5 subjects, 10 eyes in each group). After insertion, post-lens tear thickness was measured at 0, 30 minutes and every hour up to 6 hours using Anterior Segment OCT. To analyze post-lens tear thickness and its rate of change at each time point, both within and between groups, a linear mixed model was used. Results: The initial mean post-lens tear thickness (µm) was 742 ± 50 and 440 ± 50 in keratoconus and normal cornea group, respectively. The mean rate of change (µm/hr) was highest in the first 30 minutes in both groups (80.8 ± 8.7, 132.2 ± 8.8 in keratoconus and normal cornea group). Following the first four hours in keratoconus and the first hour in normal cornea group, the reduction rate in post-lens tear thickness exhibited no statistically significant difference from the rate of change observed during the 5-6 hour period. The mean percentage of total change over 6 hours after lens insertion was higher in normal cornea compared to keratoconus group (36.6% vs 22.5%). Conclusion: The reduction in post-lens tear thickness follows a nonlinear pattern. The mean rate of change was highest after insertion and remained stable after four hours in keratoconus and one hour in normal cornea group. The percent change over the 6-hour period was greater in normal cornea group.

Objective: To compare visual field (VF) parameters and pupil size as measured through colored and clear contact lenses (CL) in Asian population. Materials and Methods: Demographic data and CL prescription data were recorded during the baseline visit. Visual acuity and autorefraction were evaluated while patients wore clear CL, followed by slit-lamp examination and intraocular pressure measurements after CL removal. During the second visit, subjects were given dark browncolored CL with their same prescription. Visual acuity and autorefraction were measured. Pupil size and VF tests were measured twice with the clear CL and the colored CL. Measurements through colored and clear CL were compared. Results: Twenty-one volunteers (mean age: 31 years) were recruited. Refractive error varied from 0.00 to -7.00 diopters. Mean horizontal meridian measured through clear and colored CL was 134.8±7.8° and 133.3±4.7°, respectively. Mean vertical meridian measured through clear and colored CL was 100.1±3.8° and 100.4±2.5°. Mean total VF area measured through clear and colored contact lenses was 9,890.9±822.8° and 9,882.7±528.1°. There was no significant difference between clear and colored CL groups for horizontal meridian, vertical meridian, total VF area, or pupil size. Conclusion: There was no significant difference in any evaluated parameters between clear and colored CL.

Objective: To study the clinical characteristics of patients attending the contact lens clinic at Siriraj Hospital. Methods: Retrospective chart indicates characteristics of new patients who attended the contact lens clinic at Siriraj Hospital from January 2008 to December 2009. Results: One hundred and thirty three eyes were collected from 85 patients (50 females and 35 males) with the mean age of 31.87 years: 40 eyes were low refractive error, 23 eyes were high myopia, 22 eyes were high hyperopia, 18 eyes were high astigmatism, 18 eyes were high myopia and high astigmatism and 12 eyes were keratoconus. The mean pre-fitting visual acuity in all groups was 0.79LogMAR (range 0 to 2.6LogMAR). Soft sphere contact lenses were mostly prescribed in low refractive error patients while PMMA contact lenses were mostly prescribed in keratoconus patients. The mean final visual acuity with contact lenses in all groups was 0.2LogMAR (range 0 to 1LogMAR). No serious contact lens related complications were found in the follow up visit. Conclusion: Many types of contact lenses can be used in different indications. Contact lenses can improve visual acuity substantially in high hyperopia patients. To wear contact lenses is a less invasive option for moderate keratoconus patients to improve vision. Patient’s education for contact lens caring is important and should be emphasized to prevent irreversible contact lens related complications.

Objective: To compare the accuracy of measuring refractive error by retinoscopy between classical and innovative teaching techniques. Methods: Thirty ophthalmic residents with best-corrected visual acuity not less than 6/9, and no color blindness were included. The first test was conducted (for all participants) by a randomized blinded practice with a five different refractive error schematic eyes for 15 minutes. After the first test, all of them were taught and practiced with the retinoscopy simulator. The second test was undergone with the same five schematic eyes but in different order for 15 minutes. The answers of the second test were recorded. Results: Seven were male and 23 were female with the mean age of 28.7 year-old. There were 10 participants in each group with less than 1 year, 1 year and 2 years experience of retinoscopy training. We found no statistical difference in the total correction score of all 3 groups before and after using retinoscopy simulator (p= 0.668). Only the group with less than 1 year of experience had a significant improvement in total correction score (p= 0.015) after using the retinoscopy simulator. Conclusion: Retinoscopy simulator can help the beginner to recognize and become familiar with the reflexes observed from retinoscopy, but it is not effective to be an alternative technique for the classical retinoscopy teaching method.

Objective: To determine the incidences of ocular toxicity and ocular findings, including structural and functional abnormalities, caused by iron chelating agents and detected by an electrophysiologic test at Siriraj Hospital. Methods: A retrospective chart review was conducted of patients receiving multiple blood transfusions and iron chelation therapy who had an eye examination at Siriraj Hospital between January 1995 and December 2017. Results: Ninety-seven charts were reviewed. The 88 patients included comprised 41 males and 47 females. Their ages ranged from 1 year 11 months to 47 years, with children predominant (mean: 8.13 years). Beta thalassemia HbE was the main diagnosis (87.5%). After receiving iron chelating agents, 3 patients had abnormal eye findings with suspected ocular toxicity. Two had retinal pigmentary changes, but only one of those two displayed a mildly decreased response in a scotopic electroretinogram. Although the third patient also showed a decreased electroretinogram response, there were no obvious retinal changes. All three received the iron chelating agents desferrioxamine, deferiprone, and/or deferasirox at different doses and for various durations. Conclusion: Although some pigmentary retinopathy and decreased electroretinogram responses were found, leading to ocular toxicity being suspected, there was a very low incidence of ocular toxicity from the chelating agents. In addition, the dosages of the agents causing ocular toxicity, and the duration of that toxicity, were inconclusive. Moreover, a gold standard for identifying ocular toxicity caused by chelating agents was not able to be established. Consequently, the risks and benefits of employing eye screening coupled with an invasive procedure like an electrophysiologic test will need to be weighed, especially with pediatric patients.

Objective: To determine the amount of triglyceride deposition from a lipid-containing artificial tear eye drop (Endura® ) on three different types of contact lenses after one day and one month of simulated use. Methods: Simulated use of artificial tears was performed in vitro on three different types of contact lenses, including: high water content (HW), low water content (LW), and silicone hydrogel (SI) contact lenses. To simulate one day of use, contact lenses were incubated in artificial tear solution for 16 hours. To simulate a one month of use, they underwent repeated cycles of 16-hour incubation in artificial tear solution, lens cleaning, and 8-hour storage in a multipurpose solution daily for 30 days. Triglyceride deposited was extracted and determined. Results: After one day of simulated use, amount of deposited triglyceride was significantly different among 3 types of contact lenses with the highest deposition in SI followed by LW and HW contact lenses; the corresponding values (mean ± SD) were 3.79 ± 0.35, 0.84 ± 0.27, and 0.26 ± 0.17 μg/lens, respectively. Only between SI and HW was it found to be statistically different. After one month of simulated use, deposition on SI lenses was slightly increased (6.56 ± 1.10 μg/lens) with that on LW and HW lenses remaining low (0.10 ± 0.12 and 0.55 ± 0.34 μg/lens, respectively). Conclusion: Triglyceride from lipid-containing artificial tears can absorb into contact lenses, particularly those made of silicone hydrogel, most notably after long periods of use. However, levels of triglyceride deposition are relatively low, when compared to lipid deposition from normal tear films during regular use.

We herein describe the first reported case of Ichthyosis Follicularis with Atrichia and Photophobia (IFAP) syndrome in Thailand. A 6-year-old boy presented with a history of photophobia since 1 month of age. Then he developed widespread follicular hyperkeratotic papules and subtotal non-scarring alopecia by the age of 10 months and 5 years, respectively. Sparse eyelashes and nail dystrophy were also noted. No neurological abnormalities, systemic involvement, and hearing impairment were observed. The clinical manifestations were consistent with IFAP syndrome, although genetic testing did not confirm the diagnosis of this rare disorder.

Objective: To evaluate the visual evoked potentials (VEP) in Graves’ disease patients in order to reveal the possible presen- tation of subclinical optic neuropathy. Methods: Forty-seven Graves’ disease patients without symptoms of optic neuropathy were enrolled. Flash visual evoked potentials (F-VEP) and Pattern visual evoked potentials (P-VEP) were evaluated. Comparison of VEP with normal values was done, between the groups with and without the presentation of eye sign(s) and also among the groups that had differ- ences in thyroid hormone function. Results: The mean F-VEP amplitude and latency were 17.56±6.20 microvolts (μV) and 114.02±14.92 milliseconds (ms), respectively. The mean P-VEP amplitude and latency were 10.82±4.88 μV and 99.67±5.87 ms, respectively. These values were within normal values. Only the latency of P-VEP was increased significantly (P

Objective: To determine the amount of triglyceride deposition from a lipid-containing artificial tear eye drop (Endura®) on three different types of contact lenses after one day and one month of simulated use. Methods: Simulated use of artificial tears was performed in vitro on three different types of contact lenses, including: high water content (HW), low water content (LW), and silicone hydrogel (SI) contact lenses. To simulate one day of use, contact lenses were incubated in artificial tear solution for 16 hours. To simulate a one month of use, they underwent repeated cycles of 16-hour incubation in artificial tear solution, lens cleaning, and 8-hour storage in a multipurpose solution daily for 30 days. Triglyceride deposited was extracted and determined. Results: After one day of simulated use, amount of deposited triglyceride was significantly different among 3 types of contact lenses with the highest deposition in SI followed by LW and HW contact lenses; the corresponding values (mean ± SD) were 3.79 ± 0.35, 0.84 ± 0.27, and 0.26 ± 0.17 µg/lens, respectively. Only between SI and HW was it found to be statistically different. After one month of simulated use, deposition on SI lenses was slightly increased (6.56 ± 1.10 µg/lens) with that on LW and HW lenses remaining low (0.10 ± 0.12 and 0.55 ± 0.34 µg/lens, respectively). Conclusion: Triglyceride from lipid-containing artificial tears can absorb into contact lenses, particularly those made of silicone hydrogel, most notably after long periods of use. However, levels of triglyceride deposition are relatively low, when compared to lipid deposition from normal tear films during regular use.

Objective: To define normal values of Electroretinogram [ERG] and Visual Evoked Potential [VEP] in different age groups using Viking Select Master Software V7.1. Methods: ERG and VEP values were measured using Viking Select Master Software V7.1 in selected subjects without history of ocular and/or systemic diseases that affect ERG and VEP values. Results were studied in three groups of age: less than 10 years old, 11 to 40 years old and over 40 years old. Results: There were 26 eyes in the first group with age range from 6-10 years old [mean 7.8 ± 1.52 years old]. In ERG : the normal values of photopic amplitude of ; a-wave was ≥ 18.57 microvoltage [μV] and b-wave was ≥ 23.82 μV, flickering amplitude of b-wave was ≥ 21.93 μV, scotopic amplitude of b-wave was ≥ 39.12 μV, mesopic amplitude of ; a-wave was ≥ 60.44 μV and b-wave was ≥ 96.84 μV. In VEP : transient flash amplitude was ≥ 20.58 μV and latency was ≤ 94.10 millisecond[ms], transient pattern size 2 amplitude was ≥ 8.61 μV and latency was ≤ 100.00 ms. There were 75 eyes in the second group with age range from 11-38 years old [mean 26.8 ± 7.35 years old]. The values of photopic amplitude of ; a-wave was ≥ 22.56 μV and b-wave was ≥ 20.14 μV, flickering amplitude of b-wave was ≥ 19.35 μV, scotopic amplitude of b-wave was ≥ 32.29 μV, mesopic amplitude of ; a-wave was ≥ 45.05 μV and b-wave was ≥ 78.97 μV, VEP- transient flash amplitude was ≥ 11.64 μV and latency was ≤ 96.78 ms, transient pattern size 2 amplitude was ≥ 4.82 μV and latency was ≤ 88.49 ms. There were 77 eyes in the third group with age range from 41-81 years old [mean 60.1 ± 11.54 years old]. The values of photopic amplitude of; a-wave was ≥ 19.12 μV and b-wave was ≥ 24.59 μV, flickering amplitude of b-wave was ≥ 18.76 μV, scotopic amplitude of b-wave was ≥ 35.60 μV, mesopic amplitude of ; a-wave was ≥ 40.90 μV and b-wave was ≥ 94.09 μV, VEP- transient flash amplitude was ≥ 10.07 μV and latency was ≤ 102.10 ms, transient pattern size 2 amplitude was ≥ 5.34 μV and latency was ≤ 96.00 ms. Conclusion: We established normal ERG and VEP values in different age group using Viking Select Master Software V7.1 at Siriraj Hospital to distinguish between normal and pathological patients. The values are affected in relation to machine and environmental setting in different laboratory. It is essential for individual laboratories to set their own normal values.