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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 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 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

Prolonged latency of visual evoked potentials (VEP) has been used to identify clinically silent lesions in multiple sclerosis (MS) suspects. The objective of this study was to determine the reliability of VEP to predict the development of MS in MS suspects. Retrospective hospital records of MS suspects were evaluated. VEP was analyzed together with subsequent diagnostic confirmation of MS by McDonald diagnostic criteria for MS-2005. MS developed in 12 of 35 patients (34 %) and 23 (66 %) failed to exhibit diagnostic characteristics. P100 latencies and interocular latency differences were longer in clinically definite multiple sclerosis (CDMS) than non-CDMS patients (p = 0.002, 0.001, respectively). All patients in the subsequent MS group had P100 latencies longer than102 ms, a mean of our MS-free subjects thus providing 100 % of sensitivity. No patient developed MS with a P100 latency

To describe the rate of change in retinal vessel width and tortuosity in eyes that develop treatment-requiring, or type 1, retinopathy of prematurity (ROP) versus eyes that do not develop type 1 ROP.Posterior poles of eyes of 41 infants at risk for ROP were imaged longitudinally with a 30° fundus camera. Retinal vessel width and tortuosity were measured with computer-assisted image analysis. The rate of change per day in width and tortuosity up to the development of most severe ROP was calculated from linear regression and eyes with (n = 10) and without type 1 ROP (n = 31) were compared.Eyes that developed type 1 ROP had a greater rate of change in width for venules and 3 widest vessels (P0.0001), and a greater rate of change in tortuosity for arterioles and 3 most tortuous vessels (P0.0001) than eyes that did not develop type 1 ROP. These vessel parameters discriminate the 2 groups well (area under the ROC curve, 0.79-0.90). A combination of venular width and arteriolar tortuosity had the best discriminative ability (area under the ROC curve, 0.96).In this pilot study, eyes that eventually developed type 1 ROP demonstrated a faster increase in width and tortuosity of retinal vessels compared with those that did not. Further study of the kinetics of retinal vascular change in a larger sample may allow for the earlier identification of vision-threatening ROP.