Contact lens wear and follow-up and its association with signs and symptoms of meibomian gland dysfunction.

INTRODUCTION: This study investigated the equivocal association between contact lens (CL) wear and meibomian gland dysfunction (MGD) by comparing the morphological, functional and subjective outcomes of CL wearers versus control, non-CL wearers. CL wearers were examined as two cohorts based on the annual attendance of follow-up visits (FLU-attended these visits, whereas non-FLU did not). METHODS: Habitual logMAR visual acuity, invasive and non-invasive tear break-up time, Schirmer test, Efron grading scales, meibum quality score (MQS), meibum expressibility score (MES), meibomian gland (MG) loss, lid margin abnormalities and subjective dry eye (DE) symptoms were assessed. RESULTS: Of the 128 participants, 31 were in the FLU cohort, 43 were in the non-FLU cohort and 54 were controls (mean ages: 22.2 ± 3.1, 23.0 ± 4.6 and 22.3 ± 3.5, respectively). Non-FLU CL wearers had more symptoms than controls (3.7 ± 2.4 vs. 2.3 ± 2.1, p < 0.01). Morphologically, FLU (16.9 ± 8.8%, p = 0.02) and non-FLU (18.6 ± 11.3%, p = 0.001) had more MG loss than controls (11.2 ± 6.8%). Functionally, FLU (0.6 ± 0.7, p = 0.01) and non-FLU (0.8 ± 0.9, p = 0.001) had worse MES than controls (0.2 ± 0.5). FLU and non-FLU were both associated with corneal staining (odds ratio [OR] = 3.42, 95% CI: 1.16-10.11, p = 0.03 and OR = 5.23, 95% CI: 1.89-14.48, p = 0.001, respectively) and MG loss (OR = 10.47, 95% CI: 1.14-96.29, p = 0.04 and OR = 16.63, 95% CI: 1.96-140.86, p = 0.01, respectively). Non-FLU CL wear was also associated with abnormal MQS (OR = 12.87, 95% CI: 1.12-148.41, p = 0.04), conjunctival staining (OR = 12.18, 95% CI: 3.66-40.51, p < 0.001) and lid margin telangiectasia (OR = 3.78, 95% CI: 1.55-9.21, p = 0.003). MGD was three times more prevalent in CL wearers (12%) than in controls (4%). CONCLUSIONS: Both CL-wearing cohorts demonstrated significantly more MG abnormalities than controls though the difference was not clinically significant. Non-FLU CL wearers had more DE symptoms. Non-FLU CL wear is an independent predictor for more abnormalities than FLU CL wear, emphasising the importance of follow-ups.

Topical review of the relationship between contact lens wear and meibomian gland dysfunction

Contact lens (CL) wearers often suffer from ocular discomfort, which leads to cessation of CL wear. About 30% to 50% of CL wearers complain of dry eye (DE) symptoms. Meibomian gland dysfunction (MGD) is considered the most common cause of evaporative DE. Numerous studies have investigated whether CL wear might affect the meibomian glands. This manuscript reviews studies examining the relationship between CL use and MGD. A PubMed database search was conducted for studies published between 1980-2021 with one or a combination of search terms related to “meibomian gland”, “meibomian gland dysfunction”, “contact lens”, and/or “dry eye”. Of the 115 papers reviewed, 22 articles were identified that examined the association between CL and MGD. Fifteen showed that CL wear affects the morphology and function of meibomian glands (MGs), while seven reported no significant impact of CL wear on MGs. This review provides an overview of these studies, emphasizing the diagnostic tests of MGD and conclusions. The review highlights the need for longitudinal prospective large cohort studies with control non- CL wearers to clarify the ambiguous relationship between MGD and CL wear, with special attention to varying CL material and wear times in order to identify the long-term impact of CLs on MG. (AU)

Topical review of the relationship between contact lens wear and meibomian gland dysfunction.

Contact lens (CL) wearers often suffer from ocular discomfort, which leads to cessation of CL wear. About 30% to 50% of CL wearers complain of dry eye (DE) symptoms. Meibomian gland dysfunction (MGD) is considered the most common cause of evaporative DE. Numerous studies have investigated whether CL wear might affect the meibomian glands. This manuscript reviews studies examining the relationship between CL use and MGD. A PubMed database search was conducted for studies published between 1980-2021 with one or a combination of search terms related to "meibomian gland", "meibomian gland dysfunction", "contact lens", and/or "dry eye". Of the 115 papers reviewed, 22 articles were identified that examined the association between CL and MGD. Fifteen showed that CL wear affects the morphology and function of meibomian glands (MGs), while seven reported no significant impact of CL wear on MGs. This review provides an overview of these studies, emphasizing the diagnostic tests of MGD and conclusions. The review highlights the need for longitudinal prospective large cohort studies with control non- CL wearers to clarify the ambiguous relationship between MGD and CL wear, with special attention to varying CL material and wear times in order to identify the long-term impact of CLs on MG.

Repeatability and reproducibility of Cobra HD fundus camera meibography in young adults with and without symptoms of dry eye.

PURPOSE: The inter-session repeatability (ISR), inter-examiner reproducibility (IER) and within-subject variability (WSV) of the Cobra HD fundus camera meibographer were examined in participants with and without dry eye symptoms. METHODS: Symptoms were determined based on Ocular Surface Disease Index scores (≥13 being considered symptomatic), and subgroups were compared using the Mann-Whitney U-test. Images of meibomian glands (MGs) from the upper and lower right eyelids were captured by two examiners on the same day (S1) to determine IER. One examiner repeated the measurements on a second day (S2) to obtain the ISR. ISR, IER and WSV were calculated using Friedman, correlation tests and Bland and Altman analyses with mean differences (md) and 95% confidence intervals (CIs), within-subject standard deviations (Sw) and intra-class correlation coefficients (ICC). RESULTS: The ISR experiment included 72 participants (mean age: 23 ± 5 years, range: 19-43, 36 symptomatic). Mean MG loss of the upper (S1: 13.5 ± 9.5%, S2: 12.8 ± 8.5%) and lower eyelids (S1: 7.5 ± 6.9%, S2: 7.3 ± 6.3%) was not significantly different between sessions for all participants, symptomatic and asymptomatic subgroups for both eyelids. The ISR Sw for the upper and lower eyelids was 1.3% and 1.0%; md was 0.7 ± 3.5% (CI:-6.25% to 7.62%) and 0.1 ± 2.1% (CI: -3.94% to 4.17%), respectively. The IER experiment included 74 participants (mean age: 23 ± 5 years, range: 19-43, 37 symptomatic). Mean MG loss of the upper (Examiner 1: 12.7 ± 8.2%, Examiner 2: 13.1 ± 8.0%) and lower eyelids (Examiner 1: 7.0 ± 6.2%, Examiner 2: 7.4 ± 6.2%) was not significantly different between examiners for all participants, symptomatic and asymptomatic subgroups for both eyelids. The IER ICC values were >0.86 for all conditions, Sw was 1.3% and 1.2%, with a md of -0.4 ± 3.2% (CI: -6.65% to 5.90%) and -0.4 ± 2.9% (CI: -6.15% to 5.31%), respectively. The WSV Sw values were <1.4%, and ICC values were >0.89 for both eyelids, examiners and experimental sessions. CONCLUSIONS: The Cobra HD fundus camera demonstrates good repeatability, reproducibility and low WSV, and is a reliable clinical instrument for meibography.

Knockdown of Dehydrodolichyl Diphosphate Synthase in the Drosophila Retina Leads to a Unique Pattern of Retinal Degeneration.

Dehydrodolichyl diphosphate synthase (DHDDS) is a ubiquitously expressed enzyme that catalyzes cis-prenyl chain elongation to produce the poly-prenyl backbone of dolichol. It appears in all tissues including the nervous system and it is a highly conserved enzyme that can be found in all animal species. Individuals who have biallelic missense mutations in the DHDDS gene are presented with non-syndromic retinitis pigmentosa with unknown underlying mechanism. We have used the Drosophila model to compromise DHDDS ortholog gene (CG10778) in order to look for cellular and molecular mechanisms that, when defective, might be responsible for this retinal disease. The Gal4/UAS system was used to suppress the expression of CG10778 via RNAi-mediated-knockdown in various tissues. The resulting phenotypes were assessed using q-RT-PCR, transmission-electron-microscopy (TEM), electroretinogram, antibody staining and Western blot analysis. Targeted knockdown of CG10778-mRNA in the early embryo using the actin promoter or in the developing wings using the nub promoter resulted in lethality, or wings loss, respectively. Targeted expression of CG10778-RNAi using the glass multiple reporter (GMR)-Gal4 driver (GMR-DHDDS-RNAi) in the larva eye disc and pupal retina resulted in a complex phenotype: (a) TEM retinal sections revealed a unique pattern of retinal-degeneration, where photoreceptors R2 and R5 exhibited a nearly normal structure of their signaling-compartment (rhabdomere), but only at the region of the nucleus, while all other photoreceptors showed retinal degeneration at all regions. (b) Western blot analysis revealed a drastic reduction in rhodopsin levels in GMR-DHDDS-RNAi-flies and TEM sections showed an abnormal accumulation of endoplasmic reticulum (ER). To conclude, compromising DHDDS in the developing retina, while allowing formation of the retina, resulted in a unique pattern of retinal degeneration, characterized by a dramatic reduction in rhodopsin protein level and an abnormal accumulation of ER membranes in the photoreceptors cells, thus indicating that DHDDS is essential for normal retinal formation.

Aberrations and topography in normal, keratoconus-suspect, and keratoconic eyes.

PURPOSE: This study was designed to compare higher order aberrations of the cornea and of the eye with inferior-superior (I-S) corneal topographic values in keratoconic eyes. METHODS: We studied 92 eyes from 78 subjects: 21 eyes of 14 subjects with suspected keratoconus, 23 eyes of 16 subjects with manifest keratoconus, and 48 eyes of 48 subjects without keratoconus using the L80 wave+, an instrument which can measure corneal topography and aberrations simultaneously with a large dynamic range making it possible to evaluate higher order aberrations to the seventh order of the Zernike polynomial function series. RESULTS: All ocular and corneal higher order aberrations were found to be significantly higher for keratoconic than normal eyes, but for suspected keratoconus the results were mixed. Corneal aberrations were higher than ocular aberrations due to compensation from the internal aberrations. For manifest keratoconus, the corneal and ocular vertical coma displayed the largest difference being 38.6 and 78.5 times higher, respectively, than normal eyes, while the largest differences for suspected keratoconus were only 5.3 and 4.0 times higher, respectively. On the other hand, inferior-superior dioptric asymmetry was 9.4 and 37.3 times higher for suspected keratoconus and keratoconic eyes, respectively, than normal eyes. The separation of normality curves between suspected keratoconus and normal eyes was 28.6% for I-S and 14.3% for both corneal vertical coma and corneal total coma. CONCLUSIONS: Although corneal vertical coma and, to a lesser extent, ocular vertical coma were found to be good indicators for the detection of keratoconic eyes, the traditional corneal topographic value such as the inferior-superior dioptric asymmetry remains an important predictor for identifying suspected keratoconus. However, ocular vertical coma and ocular higher order total root mean square also represent a good means of identifying suspected keratoconus.