Comparing goblet cell densities in patients wearing disposable hydrogel contact lenses versus silicone hydrogel contact lenses in an extended-wear modality

Differences between Inferior and Superior Bulbar Conjunctiva Goblet Cells in Scleral Lens Wearers: A Pilot Study

SIGNIFICANCE

Scleral lenses (SLs) rest on the scleroconjunctival region, which could result in a mechanical impact in the bulbar conjunctiva that can hypothetically modify some properties of conjunctival cells.

PURPOSE

The purpose of this study was to evaluate the differences in goblet cell density (GCD) and mucin cloud amplitude (MCA) between superior and inferior bulbar conjunctiva in SL wearers.

METHODS

A total of 26 eyes wearing SL were randomly selected from 26 subjects (11 females) with different grades of keratoconus enrolled in a prospective clinical series. Superior and inferior conjunctival impression cytologies were performed and therefore analyzed with scanning laser confocal microscopy to evaluate GCD and MCA. All subjects filled out the Ocular Surface Disease Index (OSDI) questionnaire.

RESULTS

The mean ± standard deviation OSDI score was 23.62 ± 15.12. Although a higher density of goblet cells was observed in the samples taken in the superior conjunctiva (74.70 ± 57.55 cells/mm) than on the inferior conjunctiva (55.91 ± 34.80 cells/mm), there were no statistically significant differences between them (P = .14, Wilcoxon). Regarding MCA, no differences were found between superior (21.81 ± 3.30 μm) and inferior (20.72 ± 2.95 μm) samples (P = .201, Wilcoxon). No statistically significant differences were found in GCD and MCA regarding the time of SL wear.

CONCLUSIONS

There were no differences in GCD and MCA in the samples taken in the superior and inferior conjunctival areas. Also, it seems that the SL wearing time does not affect the density and secretion of goblet cells. Prospective studies need to be conducted in larger samples to confirm those outcomes.

Non-invasive objective and contemporary methods for measuring ocular surface inflammation in soft contact lens wearers - A review

Contact lens wear is one of the primary risk factors for the development of ocular surface inflammatory events. The purpose of this review is to examine and summarize existing knowledge on the mechanisms of contact lens related ocular surface inflammation and the evidence for the effectiveness of current objective methods to measure ocular surface inflammation. Contact lens wear is postulated to trigger an inflammatory response on the ocular surface due to mechanical, chemical, hypoxic stress, or by the introduction of microbes and their toxins. Apart from the traditional signs of inflammation, such as swelling, oedema, redness and heat, on the ocular surface, other methods to measure ocular surface inflammation in sub-clinical levels include tear inflammatory mediator concentrations, conjunctival cell morphology, and corneal epithelial dendritic cell density and morphology. Tear inflammatory mediator concentrations are up- or down-regulated during contact lens wear, with or without the presence of associated inflammatory events. There is higher conjunctival cell metaplasia observed with contact lens wear, but changes in goblet cell density are inconclusive. Dendritic cell density is seen to increase soon after initiating soft contact lens wear. The long term effects of contact lens wear on dendritic cell migration in the cornea and conjunctiva, including the lid wiper area, require further investigation. Currently patient factors, such as age, smoking, systemic diseases and genetic profile are being studied. A better understanding of these mechanisms may facilitate the development of new management options and strategies to minimize ocular surface inflammation related to contact lens wear.

Conjunctival Goblet Cell Function: Effect of Contact Lens Wear and Cytokines

This review focuses on conjunctival goblet cells and their essential function in the maintenance of eye health. The main function of goblet cells is to produce and secrete mucins that lubricate the ocular surface. An excess or a defect in those mucins leads to several alterations that makes goblet cells central players in maintaining the proper mucin balance and ensuring the correct function of ocular surface tissues. A typical pathology that occurs with mucous deficiency is dry eye disease, whereas the classical example of mucous hyperproduction is allergic conjunctivitis. In this review, we analyze how goblet cell number and function can be altered in these diseases and in contact lens (CL) wearers. We found that most published studies focused exclusively on the goblet cell number. However, recent advances have demonstrated that, along with mucin secretion, goblet cells are also able to secrete cytokines and respond to them. We describe the effect of different cytokines on goblet cell proliferation and secretion. We conclude that it is important to further explore the effect of CL wear and cytokines on conjunctival goblet cell function.

Effect of three months of soft contact lens wear on conjunctival cytology

BACKGROUND

The purpose of this study was to investigate the effect of three months of soft contact lens wear on conjunctival goblet cell density and epithelial cell morphology.

METHODS

This was a longitudinal clinical trial. Conjunctival impression cytology was performed on the superior palpebral conjunctiva in fifty-four eyes of twenty-seven neophyte contact lens wearers before and after three months of contact lens wear. Goblet cell density was determined by optical microscopy and epithelial cell morphology was classified according to the Tseng classification. Changes in goblet cell density as well as epithelial cell grading were determined. The effects of lens material and wearing modality on cytological changes were also investigated.

RESULTS

Goblet cell density reduced significantly by 85 ± 151 cells/mm(2) (p < 0.001) after three months of contact lens wear. Reduction in goblet cell density was associated with lens materials; it was higher in conventional hydrogel lenses in comparison to silicone-hydrogel lenses (p = 0.008). The highest reduction in goblet cell density was found with Nelfilcon A lens wear (p = 0.002) and the lowest with Comfilcon A lens wear (p = 0.414). There was no statistically significant difference in grading of epithelial metaplasia before and after three months of contact lens wear (p = 0.075). Age was not correlated with the reduction in goblet cell density (r = -0.196, p = 0.160) but it was associated with the change in epithelial cell morphology (p = 0.036).

CONCLUSION

Three months of soft contact lens wear statistically significantly reduced goblet cell density; however, no significant changes were found in the grading of epithelial metaplasia. Contact lenses with lower oxygen permeability, higher Young modulus and higher thickness highly affected the conjunctival cytology.

Effect of overnight orthokeratology on conjunctival goblet cells

OBJECTIVE

To evaluate the differences between goblet cell density (GCD) and symptomatology after one month of orthokeratology lens wear.

METHODS

A pilot, short-term study was conducted. Twenty-two subjects (29.7±7.0 years old) participated voluntarily in the study. Subjects were divided into two groups: habitual silicone hydrogel contact lens wearers (SiHCLW) and new contact lens wearers (NCLW). Schirmer test, tear break up time (TBUT), Ocular Surface Disease Index (OSDI) questionnaire and conjunctival impression cytology. GCD, mucin cloud height (MCH) and cell layer thickness (CLT) were measured. All measurements were performed before orthokeratology fitting and one month after fitting to assess the evolution of the changes throughout this time.

RESULTS

No differences in tear volume and TBUT between groups were found (p>0.05). However, the OSDI score was statistically better after one month of orthokeratology lens wear than the baseline for the SiHCLW group (p=0.03). Regarding the goblet cell analysis, no differences were found in CLT and MCH from the baseline visit to the one month visit for the SiHCLW compared with NCLW groups (p>0.05). At baseline, the GCD in the SiHCLW group were statistically lower than NCLW group (p<0.001). There was a significant increase in GCD after orthokeratology fitting from 121±140cell/mm(2) to 254±130cell/mm(2) (p<0.001) in the SiHCLW group.

CONCLUSION

Orthokeratology improves the dry eye subject symptoms and GCD after one month of wearing in SiHCLW. These results suggest that orthokeratology could be considered a good alternative for silicone hydrogel contact lens discomfort and dryness.

Changes in the tear film and ocular surface after cataract surgery

PURPOSE

To evaluate changes in corneal sensitivity, tear film function, and ocular surface stability in patients after cataract surgery.

METHODS

This hospital-based prospective randomized trial included 48 eyes from 30 patients who underwent phacoemulsification. Slit-lamp examination, Schirmer test 1 (ST1), and measurement of corneal sensitivity and tear film breakup time (BUT) were performed for all patients 1 day before and 1 day, 1 month, and 3 months after surgery. In addition, conjunctival impression cytology from the temporal region of the conjunctiva was simultaneously performed.

RESULTS

Corneal sensitivity at the center and temporal incision sites had decreased significantly at 1 day postoperatively (P = .021, P < .001). However, the sensitivity had returned to almost the preoperative level 1 month postoperatively. The mean postoperative ST1 results were no different from preoperative values. On the other hand, BUT results had decreased significantly at 1 day postoperatively (P = .01) but had returned to almost the preoperative level 1 month postoperatively. Mean goblet cell density (GCD) had decreased significantly at 1 day, 1 month, and 3 months postoperatively (P < .001). In addition, decrease in GCD and cataract operative time were highly correlated (r² = 0.65).

CONCLUSIONS

The decrease in GCD, which was correlated with operative time, had not recovered at 3 months after cataract surgery. Therefore, microscopic ocular surface damage during cataract surgery seems to be one of the pathogenic factors that cause ocular discomfort and dry eye syndrome after cataract surgery.

Goblet cells of the normal human bulbar conjunctiva and their assessment by impression cytology sampling

Goblet cells of the conjunctiva are the main source of mucus for the ocular surface. The objectives of this review are to consider the goblet cells as assessed by various histological, cytological and electron microscopy methods, and to assess the consistency of published reports (over more than 25 years) of goblet cell density (GCD) from impression cytology specimens from nominally healthy human subjects. Reported GCD values have been notably variable, with a range from 24 to 2226 cells/mm² for average values. Data analysis suggests that a high density of goblet cells should be expected for the healthy human conjunctiva, with a tendency toward higher values in samples taken from normally covered locations (inferior and superior bulbar conjunctiva) of the open eye (at 973 +/- 789 cells/ mm²) than in samples taken from exposed (interpalpebral) locations (at 427 +/- 376 cells/mm²). No obvious change in GCD was found with respect to age, perhaps because the variability of the data did not allow detection of any age-related decline in GCD. Analyses of published data from 33 other sources indicated a trend for GCD to be lower than normal across a spectrum of ocular surface diseases.

Contact lens wear and the goblet cells of the human conjunctiva-A review

PURPOSE

To review the reported effects of contact lens wear on the goblet cells of the human conjunctiva.

METHODS

A literature search was undertaken to identify reports on the conjunctival health after contact lens wear, principally as assessed using the conjunctival impression cytology (CIC) technique in which cells are examined ex vivo, after fixation and staining. Details of technique, data on duration of contact lens wear and then CIC outcome in terms of goblet cell density (GCD) were extracted.

RESULTS

Of 24 reports identified, 22 examined the bulbar conjunctiva and 2 examined the tarsal conjunctiva. A decrease in GCD was considered, directly or indirectly, to be a consequence of contact lens wear in 18 of the studies, but there was no obvious overall relationship between duration of lens wear and the GCD changes. Conversely, four reports indicated an increase in GCD or goblet cell-related mucins. Two reports concluded that there was no change in goblet cells or their mucin, a result however that is consistent with a recent conclusion that no statistically significant change in GCD was detectable in contact lens wearers assessed by in vivo imaging of the human conjunctiva by confocal microscopy.

CONCLUSIONS

The majority of published studies have concluded that contact lens wear results in a decrease in goblet cells in the conjunctiva. While there are reports that draw a very different conclusion, it should be noted that there has been limited consistency in technique or the method of reporting the results across the various studies.

Confocal microscopy of the bulbar conjunctiva in contact lens wear

PURPOSE

The aim of this study was to investigate the capabilities of laser scanning confocal microscopy (LSCM) for undertaking qualitative and quantitative investigations of the response of the bulbar conjunctiva to contact lens wear.

METHODS

LSCM was used to observe and measure morphological characteristics of the bulbar conjunctiva of 11 asymptomatic soft contact lens wearers and 11 healthy volunteer subjects (controls).

RESULTS

The appearance of the bulbar conjunctiva is consistent with known histology of this tissue based on light and electron microscopy. The thickness of the bulbar conjunctival epithelium of lens wearers (30.9 +/- 1.1 microm) was less than that of controls (32.9 +/- 1.1 microm) (P < 0.0001). Superficial and basal bulbar conjunctival epithelial cell densities in contact lens wearers were 91% and 79% higher, respectively, than that in controls (P < 0.0001). No difference was observed in goblet and Langerhans cell density between lens wearers and controls. Conjunctival microcysts were observed in greater numbers, and were larger in size, in lens wearers compared with controls.

CONCLUSIONS

The effects of contact lens wear on the human bulbar conjunctiva can be investigated effectively at a cellular level using LSCM. The observations in this study suggest that contact lens wear can induce changes in the bulbar conjunctiva such as epithelial thinning and accelerated formation and enlargement of microcysts, increased epithelial cell density, but has no impact on goblet or Langerhans cell density.

Nucleus and cell size changes in human bulbar conjunctival cells after soft contact lens wear, as assessed by impression cytology

PURPOSE

To specifically assess the nucleus size and its relationship to cell size for human bulbar conjunctival cells.

METHODS

Impression cytology samples were taken from the nasal side of the intra-palpebral zone of the bulbar conjunctival surface from 20 young adult white European males, half of whom were successful daily soft contact lens wearers. A Millcell-CM filter was used, after topical anaesthesia with oxybuprocaine 0.4%, which was stained with Giemsa and colour images taken at 400x magnification by light microscopy. The images were graded and also a 35mm was prepared. From the projected image, an overlay method was used to outline the borders such that the cell and nucleus areas could be measured by planimetry.

RESULTS

The group mean cell area values were 267+/-59microm(2) (n=10, +/-S.D.) and 1028+/-357microm(2) for the non-contact lens wearers and contact lens wearers, respectively. The cell nucleus areas were 64+/-11microm(2) and 99+/-19microm(2), respectively. Both the cell areas and nucleus area values were statistically different between the two groups (p<0.001).

CONCLUSIONS

These studies confirm that soft contact lens wear can result in cell enlargement (squamous metaplasia) of the bulbar conjunctival cells. With this cell enlargement, the nucleus-to-cytoplasm ratio also changes, but the nucleus size generally increases (rather than decreases).

Investigation of dry eye disease and analysis of the pathogenic factors in patients after cataract surgery

PURPOSE

To study dry eye and analyze pathogenic factors in patients after cataract surgery.

METHODS

A total of 37 patients (50 eyes) were studied by using a 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ25) and Ocular Surface Disease Index (OSDI) 3 days before and 1 week, 1 month, and 3 months after cataract surgery. Slit-lamp microscope examination, cornea and conjunctiva fluorescein staining, tear breakup time (BUT), Schirmer test I (STI), and impression cytology (IC) were carried out at the same time. Cytologic specimens for IC were obtained from the upper lid-covered region, explosive region, and lower lid-covered region of the globe conjunctiva. The average density of goblet cells on these 3 regions was measured, and the pathogenic factors of dry eye after cataract surgery were analyzed.

RESULTS

After cataract surgery, the incidence of dry eye increased dramatically; NEI-VFQ25 and OSDI indicated that most patients developed this symptom after surgery. The lacrimal river line became narrow, and BUT and STI decreased in patients after cataract surgery. IC suggested the presence of serious squamous metaplasia in the epithelial layer of the globe conjunctiva, especially the lower lid region.

CONCLUSIONS

Dry eye can develop or deteriorate after cataract surgery if not treated in time. Misuse of eyedrops is one of the major pathogenic factors that causes dry eye after cataract surgery. Eyedrops should be carefully administered before and after cataract surgery to avoid or reduce the occurrence of dry eye postoperatively.

Research in Dry Eye: Report of the Research Subcommittee of the International Dry Eye WorkShop (2007)

Members of the DEWS Research Subcommittee reviewed research into the basic mechanisms underlying dry eye disease. Evidence was evaluated concerning the tear film, lacrimal gland and accessory lacrimal glands, ocular surface epithelia (including cornea and conjunctiva), meibomian glands, lacrimal duct system and the immune system. Consideration was given to both animal and human research data. Results are presented as a series of information matrices, identifying what is known and providing supporting references. An attempt is made to identify areas for further investigation.

The Definition and Classification of Dry Eye Disease: Report of the Definition and Classification Subcommittee of the International Dry Eye Workshop (2007)

The aim of the DEWS Definition and Classification Subcommittee was to provide a contemporary definition of dry eye disease, supported within a comprehensive classification framework. A new definition of dry eye was developed to reflect current understanding of the disease, and the committee recommended a three-part classification system. The first part is etiopathogenic and illustrates the multiple causes of dry eye. The second is mechanistic and shows how each cause of dry eye may act through a common pathway. It is stressed that any form of dry eye can interact with and exacerbate other forms of dry eye, as part of a vicious circle. Finally, a scheme is presented, based on the severity of the dry eye disease, which is expected to provide a rational basis for therapy. These guidelines are not intended to override the clinical assessment and judgment of an expert clinician in individual cases, but they should prove helpful in the conduct of clinical practice and research.