Medical hypothesis, discovery & innovation in optometry

Background: Episcleritis is a common ocular inflammatory disease that can cause red eye. It is usually managed using single or combined topical corticosteroids and topical or oral non-steroidal anti-inflammatory drugs (NSAIDs) as directed by clinical response. However, recurrence is possible. This study aimed to compare the effects of add-on therapies using different topical NSAIDs in the management of treatment-naive, non-infectious, non-necrotizing episcleritis.
Methods: Seventy-five eyes of 75 patients with non-infectious, non-necrotizing unilateral episcleritis were included in this study. Patients were allocated to one of three groups based on the NSAID used as add-on therapy: topical diclofenac sodium 0.1% (group D), topical nepafenac 0.1% (group N1), and topical nepafenac 0.3% (group N3). The time to symptom disappearance was defined as the recovery time.  
Results: There were no statistically significant differences in age, sex, initial best-corrected distance visual acuity, and intraocular pressure between groups (all P > 0.05). The mean recovery times of groups D and N1 were comparable (12.86 ± 5.35 days and 11.45 ± 5.42 days, respectively) (P > 0.05). However, the mean recovery time of group N3 was significantly shorter (9.70 ± 3.80 days, P < 0.05). Recurrence was observed in only one patient in group N1 at 3 months, and symptoms resolved when the same medication was reinstituted. Furthermore, we noted no side effects during the follow-up period for any of the treatment modalities. 
Conclusions: All three topical NSAIDs were effective add-on therapies in the management of non-infectious, non-necrotizing unilateral episcleritis. However, once-daily administration of topical nepafenac 0.3% had a shorter recovery time than topical diclofenac 0.1% and topical nepafenac 0.1%.

Background: A vision-screening program is effective in prevention of vision impairment. The validity of vision screening conducted by nurses, medical assistants, and teachers has been previously reported. However, the validity of preschool teachers in conducting external eye observations in preschool children has not been widely investigated. This study aimed to determine validity of preschool teachers in conducting external eye observation tests, including the observation of behavior and external eye health, in preschool children.Methods: In this cross-sectional study, preschool teachers from Kemajuan Masyarakat kindergarten in Klang Valley, Malaysia, were randomly allocated to the study (n = 30) or control (n = 30) groups. The study group underwent theory training with an optometrist and practical sessions with preschool children on vision screening, while the control group received only brief verbal instructions on steps to conduct the screening. After the briefing, teachers from both groups conducted vision screening tests at their kindergartens on preschool children aged 4–6 years. The same vision screening procedure was repeated in the same children by optometrists to verify results of the teachers. Results: A total of 700 preschool children were screened by 60 preschool teachers and optometrists. Teachers from the study and control groups displayed high validity in screening for external ocular health, including sensitivity (66.67% versus 66.67%), specificity (95.21% versus 95.54%), and negative predictive value (99.41% versus 99.69%). The positive predictive value was slightly higher in the study group (19.05%) than in the control group (11.76%). Conclusions: Preschool teachers competently observed external eye health in preschool children. A training module for vision screening is important, and a revision of the current training module is needed. Empowering preschool teachers could help in the early detection and intervention necessary in needy children. This could reduce the nationwide prevalence of visual impairments.

Background: Myopia is a common refractive error with an expected increase in prevalence. Inequalities in access to ocular health care for sight-threatening or life-threatening ocular diseases have been described. Urbanization is a risk factor for both the incidence and progression of myopia; however, socioeconomic inequalities in urban settings are a new concept in myopia incidence.Hypothesis: Considering the proven impact of inequalities existing in general and ocular health, urban inequality could be a new risk factor for both the incidence and progression of myopia. Inequalities in urban infrastructure vary between countries; however, there are currently various manifestations of urban inequality, and scholars are concerned about intra-urban inequality as a public health risk. Considering the significant influence of urban inequality on health of children, and because myopia develops and progresses faster during childhood, the effect of urban inequality on myopia must be examined. Although urban inequality could be a putative risk factor for myopia, a causal relationship should be investigated. However, myopia is multifactorial in etiology, originating from the interaction of environmental and genetic factors. Thus, causality between urban inequality and myopia should be investigated through a randomized, controlled trial with strict matching of genetic backgrounds and environmental factors. Conclusions: Several risk factors for myopia have been proposed, and studies have confirmed causal relationships with most of these factors. Considering the proven impact of urban inequality on both general and ocular health, experimental studies are necessary to confirm the possible causal relationship between urban inequality and myopia. Certainly, there will be substantial challenges in the implementation phase.

Background: Mitomycin C (MMC) is used to prevent corneal opacity after photorefractive keratectomy (PRK). This study sought to determine the effect of MMC on tear film function after PRK in eyes with mild-to-moderate myopia.Methods: This prospective, contralateral eye comparison was conducted on 30 eyes of 15 patients with low-to-moderate myopia referred to Alzahra Eye Hospital, Zahedan, Iran. The eyes of the control group underwent PRK with a balanced salt solution, while the fellow eyes in the intervention group underwent PRK with 0.02% MMC for 25 s. The tear breakup time test (TBUT) and basic Schirmer test results of eyes in the control and intervention groups were compared at baseline and 1, 3, and 6 months postoperatively. Tear osmolarity was recorded and compared at baseline and 3 months postoperatively. Results: The mean ± standard deviation (SD) age of participants was 27.53 ± 7.04 years. No statistically significant differences were observed in the means ± SDs for tear osmolarity, TBUT, and basic Schirmer test values (all P > 0.05) between MMC-treated eyes and untreated fellow eyes at baseline and during postoperative follow-up. The means ± SDs for tear osmolarity, TBUT, and basic Schirmer test results were comparable in both groups between the baseline and postoperative follow-ups (all P > 0.05). Conclusions: Single application of a standard dose of MMC (0.02%) for 25 s in PRK did not change tear stability, tear production, or variation in tear dynamics up to 6 months postoperatively in eyes with low-to-moderate myopia. Future longitudinal studies with a longer follow-up and a larger sample size are warranted to confirm our findings.

Background: Eyelids have been shown to influence corneal shape. The effects of eyelid pathologies on corneal astigmatism have been widely investigated. This study aimed to determine the correlation between levator palpebrae superioris (LPS) muscle function and with-the-rule (WTR) corneal astigmatism in university students with normal eyelid morphology.Methods: This was a cross-sectional study with a sample of 58 university students of Chinese origin selected by simple random sampling at the University College Sedaya International (UCSI) University Optometry Clinic, Kuala Lumpur, Malaysia. We included participants aged 18 to 30 years, regardless of sex, with normal eyelid morphology, normal LPS function, and WTR corneal astigmatism. For LPS muscle function, the distance of the upper eyelid margin from the maximal downgaze to the upgaze was measured, while the frontalis function was negated by the thumb of the examiner. Corneal astigmatism was measured using a manual Keratometry (Topcon OM-4; Topcon Corporation, Tokyo, Japan). Results: Of the 58 participants, 23 (39.7%) were men and 35 (60.3%) were women. The mean ± standard deviation (SD) age was 23.22 ± 1.77 years. For all participants, the means ± SDs for LPS muscle function and corneal astigmatism were 14.72 ± 1.74 mm and - 1.16 ± 0.47 D, respectively. Of the 58 participants, 25 and 33 had low and moderate WTR corneal astigmatism, respectively. The mean LPS muscle functions were not significantly different between the low and moderate WTR corneal astigmatism groups (P > 0.05). A positive but statistically insignificant correlation (r = + 0.14; P > 0.05) was found between LPS muscle function and WTR corneal astigmatism. Conclusions: We found no significant difference in the mean LPS muscle function between low and moderate WTR corneal astigmatism groups in young university students of Chinese origin with normal eyelid morphology. Furthermore, no significant correlation was found between LPS muscle function and low-to-moderate WTR corneal astigmatism.

Letter to the Editor