Peripapillary retinal nerve fibre layer thickness measurement with SD-OCT in normal and glaucomatous eyes:distribution and correlation with age

AIM:To determine peripapillary retinal fiber layer thickness (RNFL) measured with spectral domain optical coherence tomography (SD-OCT) in normal and glaucomatous eyes in a large sample of exclusively white population and compare results with other similarly constructed studies.METHODS:Average, maximum, minimum and per quadrant RNFL thickness were measured in normal and glaucomatous Greek patients with a scanning laser ophthalmoscope (SLO)/SD-OCT device. The effect of age in normal RNFL thickness was also determined.RESULTS: A total of 278 normal (278 patients) and 67 glaucomatous (67 patients) eyes were included in the study. Average RNFL thickness was 114.8±13.3μm in normal and 92.1±18.5μm in glaucomatous eyes (P<0.001). In normal discs, superior quadrant was the thickest, followed by the inferior, nasal and temporal. Decline of normal RNFL thickness with age was statistically significant for average RNFL thickness (1.92μm per decade of life) and for the superior and inferior quadrants of the disc.CONCLUSION:SD-OCT peripapillary RNFL measurements can be used to distinguish between normal and glaucomatous eyes and establish normative databases, since normal disc measurements differ between different ethnic groups and between different SD-OCT devices.     

Comparison of tear osmolarity and ocular comfort between daily disposable contact lenses: hilafilcon B hydrogel versus narafilcon A silicone hydrogel

The aim of this study was to evaluate tear osmolarity and ocular comfort with two different types of hydrogel daily disposable lenses. The right eyes of 15 first-time contact lens users were included in this prospective study. All eyes wore hilafilcon B silicone hydrogel contact lenses for 8 h (group 1). After 1 week without contact lenses, all eyes wore narafilcon A silicone hydrogel contact lenses for 8 h (group 2). Tear osmolarity measurement was performed before and after 4 and 8 h of each contact lens wear. Ocular comfort was assessed after 4 and 8 h of each contact lens wear. In group 1, the mean baseline, 4- and 8-h tear osmolarity values were 293 ± 10.57, 303.00 ± 10.5 mOsm/L (p = 0.023), and 295.0 ± 1.4 mOsm/L (p > 0.05), respectively. In group 2, the mean baseline, 4- and 8-h tear osmolarity values were 294 ± 13.65, 300.9 ± 11.3 mOsm/L (p = 0.007), and 298.80 ± 7.2 mOsm/L (p > 0.05), respectively. In group 1, the mean comfort score was 7.20 ± 0.45 and 8.60 ± 0.45 at 4 and 8 h, respectively (p = 0.038). In group 2, the mean comfort score significantly decreased from 9.80 ± 0.45 to 7.80 ± 0.84 at 4 h (p = 0.039). Both hydrogel and silicone hydrogel daily disposable contact lenses elevated tear osmolarity during 8 h of contact lens wear. The increase in tear osmolarity with both contact lenses was below the cut-off value for dry eye and was not associated with ocular comfort.     

Changes in ocular physiology, tear film characteristics, and symptomatology with 18 months silicone hydrogel contact lens wear.

PURPOSE: The purpose of this study was to evaluate the longitudinal changes in ocular physiology, tear film characteristics, and symptomatology experienced by neophyte silicone hydrogel (SiH) contact lens wearers in a daily-wear compared with a continuous-wear modality and with the different commercially available lenses over an 18-month period. METHODS: Forty-five neophyte subjects were enrolled in the study and randomly assigned to wear one of two SiH materials: lotrafilcon A or balafilcon A lenses on either a daily- (LDW; BDW) or continuous-wear (LCW; BCW) basis. Additionally, a group of noncontact lens-wearing subjects (control group) was also recruited and followed over the same study period. Objective and subjective grading of ocular physiology were carried out together with tear meniscus height (TMH) and noninvasive tear breakup time (NITBUT). Subjects also subjectively rated symptoms and judgments with lens wear. After initial screening, subsequent measurements were taken after 1, 3, 6, 12, and 18 months. RESULTS: Subjective and objective grading of ocular physiology revealed a small increase in bulbar, limbal, and palpebral hyperemia as well as corneal staining over time with both lens materials and regimes of wear (p < 0.05). No significant changes in NITBUT or TMH were found (p > 0.05). Subjective symptoms and judgment were not material- or modality-specific. CONCLUSIONS: Daily and continuous wear of SiH contact lenses induced small but statistically significant changes in ocular physiology and symptomatology. Clinical measures of tear film characteristics were unaffected by lens wear. Both materials and regimes of wear showed similar clinical performance. Long-term SiH contact lens wear is shown to be a successful option for patients.     

Comparison of tear-film osmolarity in different types of contact lenses.

PURPOSE: To investigate the tear-film osmolarity of contact lens wearers for different types of contact lenses. METHODS: Fifty six eyes of 56 cases were evaluated in four different groups according to the type of contact lens worn, with 14 eyes in each group. Groups 1 and 2 consisted of subjects who wore frequent-replacement daily wear soft contact lenses; group 1 lenses had 55% water content, and lenses in group 2 had 38% water content. Groups 3 and 4 consisted of subjects who wore rigid gas-permeable contact lenses, with a Dk value of 90 in group 3 and a Dk value of 52 in group 4. Tear-film osmolarity values in milliosmole (mosm) units were determined by auto-osmometer (Orstat 6030, Daiichi Kagacu, Kyoto, Japan) before and after contact lens wear for each group, and the results were compared statistically by ANOVA test. RESULTS: Before the period of contact lens wear, the tear-film osmolarity values of group 1, 2, 3, and 4 were 283.61+/-12.83 mosm, 285.23+/-8.94 mosm, 285.57+/-11.39 mosm, and 280.15+/-12.07 mosm, respectively. After the period of contact lens wear, these values were measured at 312.15+/-16.03 mosm in group 1, 316.54+/-12.14 mosm in group 2, 313.14+/-9.66 mosm in group 3, and 316.38+/-11.60 mosm in group 4. Although the difference between the values before and after the period of contact lens wear was statistically significant for each group (F=291.45; P=0.0005), there was no statistically significant difference among the groups. CONCLUSIONS: When a contact lens is placed in the eye, the lens alters the normal structure of the tear film and affects its rate of evaporation; therefore tear-film osmolarity may increase. In our study, all contact lenses produced a similar effect on tear-film osmolarity.     

The effect of eye closure on the post-lens tear film thickness during silicone hydrogel contact lens wear

PURPOSE: The purpose of this study was to investigate the effect of eye closure on the thickness on the post-lens tear film (POLTF) during silicone hydrogel contact lens wear. METHODS: Ten subjects (mean age, 30.2 +/- 8.6 years; seven males) wore balafilcon A silicone hydrogel contact lenses in both eyes during the experimental procedure (power = -2.00 D, base curve = 8.6 mm). Previously described interference techniques, based on oscillations in reflectance spectra, were used to measure the post-lens tear film. Reflectance spectra (562-1030 nm) from the front of the eye wearing a contact lens were measured at normal incidence where the thickness of the POLTF was derived from the "frequency" of the oscillations. Six baseline measures of POLTF thickness were taken, followed by eye closure in the supine position for 30 minutes. Post-lens tear film thickness measures were taken after 5 and 15 minutes of eye closure. After 30 minutes of eye closure, 1 measure of POLTF was taken every minute for an additional 15 minutes. RESULTS: The average baseline POLTF thickness was 2.00 +/- 0.30 microm (median, 2.00) for the 10 subjects. The average POLTF thickness decreased to 1.58 +/- 0.33 and 1.20 +/- 0.23 microm after 5 and 15 minutes of eye closure, respectively (repeated measures ANOVA, F = 42.18, P < 0.0001). Only 5 of 60 POLTF thickness estimates were obtained for the first 6 minutes following completion of 30 minutes of eye closure, indicating that the POLTF may be too thin (i.e., <1 microm) to measure using this method. However, there was a significant increase in POLTF thickness for 15 minutes after prolonged eye closure (mixed modeling regression, thickness = 0.85 + 0.07 x time after eye opening; P < 0.0001). CONCLUSIONS: The POLTF thickness is rapidly reduced by eye closure during contact lens wear. After 30 minutes of eye closure, the POLTF thickness may be reduced to values less than 1 microm for the first several minutes after opening the eyes.     

The effects of six months of contact lens wear on the tear film, ocular surfaces, and symptoms of presbyopes.

PURPOSE: To assess the tear film, ocular surfaces, and symptoms of ocular discomfort in a presbyopic population before and after contact lens wear. METHODS: A total of 150 presbyopes (49% were previous soft contact lens wearers) participated in a clinical trial in which they wore either monovision (single vision Acuvue lenses) or Acuvue Bifocal contact lenses. Clinical measurements of tear film, biomicroscopy, and corneal sensitivity as well as subjective ratings using the Dry Eye Questionnaire were collected at the initial visit and repeated after 6 months. Comparisons were made between age groups (40 to 51 years and 52 to 71 years) and genders before and after contact lens wear. Associations between objective and subjective tests were sought. RESULTS: After 6 months of contact lens wear, clinical signs had worsened by less than one-half of a grade, and tear break up time (TBUT) worsened by 3 s. Only TBUT was lower for the older age group. Females had less bulbar hyperemia, more sensitive eyes, more lissamine green staining, and lower TBUT and phenol red thread measurements (all p < 0.04). Twenty-eight percent experienced dryness before contact lens wear, but this figure increased to 68% when wearing contact lenses. There were no age differences, but almost twice as many females as males reported dryness. Reporting symptoms of dryness was associated with gender, corneal sensitivity, and type of corneal staining. CONCLUSIONS: These results provide a representation of the ocular surface condition and symptoms of ocular discomfort in the middle-aged population and seem similar to reports of younger populations. Wearing contact lenses seems to influence dry eye symptoms more than age or gender. Therefore, presbyopes should not be excluded from consideration for contact lens fitting.     

The ocular response to extended wear of a high Dk silicone hydrogel contact lens

Purpose: A four‐month extended wear clinical trial was conducted to compare die ocular effects of a high Dk Balafilcon A silicone hydrogel lens and a low Dk HEMA 38.6 per cent H²O soft lens. Method: Twenty‐four subjects who were adapted to daily wear of soft lenses wore a high Dk lens in one eye and a low Dk HEMA lens in the other eye for four months on an extended wear basis after one week of daily wear. Thirteen progress evaluations were conducted using standard clinical procedures. Results: Eighteen subjects (75 per cent) completed the study. The high Dk lens induced significantly less bulbar and limbal injection and corneal vascularisation dian the low Dk HEMA lens (p < 0.05). Epithelial microcysts were observed only in the eyes wearing the low Dk lens. A significant increase in myopia was found in die eyes wearing die low Dk HEMA lens (mean = 0.50 D, p < 0.01) compared to die insignificant myopic increase of 0.06 D in the eyes wearing the high Dk lens. Three subjects developed small infiltrates in the high Dk lens wearing eyes and significantly more post‐lens debris was observed under the high Dk lens. Six subjects developed papillary conjunctivitis in die eye wearing silicone hydrogel lenses but only two of those were discontinued from the study. Conclusion: No hypoxia‐related effects were observed with extended wear of the high Dk Balafilcon A silicone hydrogel lens.     

Mucin balls with wear of conventional and silicone hydrogel contact lenses.

PURPOSE: To compare the frequency of mucin balls in subjects wearing conventional and high-Dk silicone hydrogel lenses during 12 months of extended-wear and to determine whether mucin balls are associated with any lens or subject characteristics. METHODS: This study used data from a clinical trial where subjects wore either conventional hydrogel (N = 69, 6-night extended-wear) or silicone hydrogel (N = 70, 30-night extended-wear) contact lenses for 12 months. The number of mucin balls and other physiological responses, lens fit and performance, and subjective patient responses to lens wear were rated at each scheduled visit. RESULTS: Subjects in the silicone hydrogel group had significantly greater numbers of mucin balls compared with subjects in the conventional hydrogel group over time (p < 0.001), but there were no significant differences in the percentage of subjects with mucin balls between the two groups. Increasing lens wettability, back surface deposits, and time of lens wear were associated with higher numbers of mucin balls in the conventional hydrogel group (p < 0.05); steeper corneal curvature and increasing lens wettability, back surface deposits, and number of microcysts were associated with higher numbers of mucin balls in the silicone hydrogel group (p < 0.05). CONCLUSIONS: This study indicates that a subset of the population is predisposed to develop mucin balls irrespective of the soft contact lens type worn, but lens type influences the degree of mucin ball formation. The relationship between lens wettability, back surface deposits, and steeper corneal curvature with mucin balls supports the hypothesis that the mechanical interaction of a lens with the surface layer of the epithelium and the tear film in association with the blinking forces of the lid is involved in mucin ball formation.     

Comparison of effectiveness of silicone hydrogel contact lens and hydrogel contact lens in patients after LASEK

AIM: To conduct a comparative study of effectiveness of silicone hydrogel contact lens and hydrogel contact lens, which are used in patients after laser-assisted subepithelial keratomileusis (LASEK). METHODS: Sixty-three patients (121 eyes) with a spherical equivalent ≤-5.0 D were chosen after undergoing LASEK in 2012 at Guangdong General Hospital. They were randomly divided into 2 groups. The silicone hydrogel group included 32 cases (61 eyes) that wore silicone hydrogel contact lenses for 4-6d after the operation, while the hydrogel group included 31 cases (60 eyes) who wore hydrogel contact lenses for 4-6d after the operation. Patients’ self-reported postoperative symptoms (including pain, photophobia, tears, and foreign body sensation) were evaluated. The healing time of the corneal epithelium, the visual acuity of patients without contact lens after epithelial healing, and the incidence of delayed corneal epithelial shedding were also assessed. The follow-up time was 1mo. RESULTS: Postoperative symptoms were milder in the silicone hydrogel group than in the hydrogel group. There were significant differences in pain, foreign body sensation, and photophobia between the 2 groups (P<0.05), although there was no significant difference in postoperative tearing (P>0.05). The healing time of the corneal epithelium in the silicone hydrogel lens group was markedly shorter than that in the hydrogel group (4.07±0.25 vs 4.33±0.82d, t=2.43, P=0.02). Visual acuity without contact lenses after healing of the corneal epithelium was better in the silicone hydrogel group compared with the hydrogel group (χ2=7.76, P=0.02). There was no significant difference in the occurrence of delayed corneal epithelial shedding between the 2 groups (P>0.05). CONCLUSION: Patients with LASEK using silicon hydrogel contact lenses had less discomfort and shorter corneal epithelial healing time compared with those using hydrogel contact lenses, suggesting that silicon hydrogel contact lenses may be considered to be a better choice of bandage contact lens after LASEK.     

Hypoxic effects on the anterior eye of high-Dk soft contact lens wearers are negligible.

PURPOSE: To determine whether the eyes of high-Dk soft contact lens wearing subjects can be discriminated from non-contact lens wearing subjects. METHODS: This study was a prospective masked assessment of 32 subjects, 16 of whom wore experimental high-Dk soft contact lenses and 16 of whom did not wear contact lenses. Subjects wore high-Dk lenses on a 30-night replacement schedule for an average of 9 months. Tear film characteristics, staining and vascularization of the cornea, conjunctival staining, and the presence of microcysts in the corneal epithelium were assessed using slitlamp microscopy. The endothelium was examined for polymegethism. RESULTS: No differences were found between the two groups in any of the variables that were examined (p > 0.05) except that the high-Dk lens wearing group had about twofold more tear film debris and 2.5-fold more severe conjunctival staining (p < 0.05). CONCLUSIONS: Hypoxia-associated effects were not apparent in the eyes of subjects wearing experimental high-Dk soft contact lenses. Conjunctival staining can generally distinguish lens wearers from non-lens wearers and can be used to discriminate between high-Dk lens wearing subjects and non-lens wearing subjects.     

Role of tear secretory IgA in hard contact lens-related changes in the tarsal conjunctiva.

The role of tear secretory IgA in contact lens-related conjunctival changes was investigated in 40 subjects (80 eyes) who wore polymethyl methacrylate (PMMA) contact lenses and 10 subjects (20 eyes) who did not wear contact lenses. The eyes in the contact lens group had significantly higher tear IgA levels than the control eyes (p < 0.05). We were not able to demonstrate a relation between increased IgA levels and the presence of symptoms or duration of contact lens wear. Increased IgA levels were correlated to papilla formation in the contact lens group. A rise in tear IgA levels seems to be the first abnormal change related to papilla formation in patients who wear PMMA contact lenses.     

Effect of hydrogel lens wear on tear film stability

Noninvasive break-up time (NIBUT) of the tears was measured in a controlled, randomized, double-masked study to assess: (1) the stability of the prelens tear film during wear of new high and low water content lenses and (2) the stability of the precorneal tear film following lens removal after 1 h of wear. The prelens tear film NIBUT of 6 subjects was found to be relatively constant over a 1-h wearing period, averaging 6.1 +/- 1.1 s (mean +/- SEM). These values were significantly (Scheffe's S test, p less than 0.05) lower than those recorded for the precorneal tear film before lens insertion (33.5 +/- 10.6; mean +/- SEM), although 85% of prelens tear film NIBUT's were greater than the 3-s average interblink period reported previously for soft lens wearers. After lens removal, precorneal tear film NIBUT was reduced significantly compared to prewear levels (Scheffe's S test, p less than 0.05) for up to 15 min. Application of the monomolecular growth model to the NIBUT recovery data revealed a half-time for recovery of 6.0 min, with recovery 95% complete 25.8 min after lens removal. Lens type was not a significant factor in tear film stability, either during wear or after lens removal. The basis for reduced precorneal tear film NIBUT after lens removal is unknown; however, a disruption of the mucin layer coating the corneal epithelium is the most likely mechanism. Indeed, the technique of measuring precorneal tear film NIBUT after lens removal may be a useful determinant of the extent to which contact lens wear disrupts the precorneal mucin layer, providing an indication of the susceptibility of the cornea to a variety of complications.     

A comparative study of biweekly disposable contact lenses: silicone hydrogel versus hydrogel

Background: Our aim was to compare the clinical performance of a biweekly (second generation) silicone hydrogel lens and a biweekly hydrogel lens worn for daily wear modality. Methods: We used a double‐masked study, in which non‐presbyopic, asymptomatic and adapted soft lens wearers were recruited. Subjects wore a silicone hydrogel lens in one eye and a hydrogel lens in the other (lens types and eyes were randomly assigned) for one month. Lenses were replaced every two weeks. Contact lens fitting, pre‐lens tear film thinning time, vision, corneal integrity and lens deposits were assessed before and every fortnight after delivery of new lenses. A questionnaire was used to compare the subjective performance of the two lens types. Results: Thirty of the 33 subjects completed the study. There were no significant differences in lens fitting (centration and movement), pre‐lens tear film thinning time, vision or corneal integrity between the two lens types. Statistically, there was no significant difference in lens deposits between the two lens types but silicone hydrogel lenses tended to have more Grade 3 to 4 lipid deposits than hydrogel lenses. Subjects found no significant differences between the two lens types in terms of vision and comfort. Preference for silicone hydrogel lenses increased from 33 at the first after‐care visit to 50 per cent at the second after‐care visit. Conclusion: This short‐term study demonstrates that the performance of silicone hydrogel and hydrogel lenses is comparable but the former tends to build up more lipid deposits than the latter. We did not find better performance in terms of ocular integrity of silicone hydrogel lenses compared to the hydrogel lenses, probably because the subjects were adapted asymptomatic contact lens wearers before commencing the study. Contact lens wearers having hypoxia‐related problems are likely to benefit from using silicone hydrogel lenses, as these lenses provide at least three times more oxygen than conventional hydrogel lenses.     

Characteristics of the pre-lens tear film during hydrogel contact lens wear

The integrity of the pre-lens tear film (PLTF) is an important determinant of the clinical performance of contact lenses. The PLTF of eight hydrogel lenses, ranging from 36.5% to 85% water content, was assessed on six asymptomatic lens wearers in a randomized, double-masked experiment. Using a specular reflection technique, the thicknesses of the lipid and aqueous phases were found to be greater on lenses of higher water content. Water content was measured before and after 90 min wear using a hand-held refractometer. Non-invasive tear break-up time was also found to be greater for higher water content lenses. No association was found between lens dehydration and PLTF characteristics. The differences in PLTF noted in this study may help to explain the differences noted between some lenses in their rates of surface deposition.     

Tear film inflammatory cytokine upregulation in contact lens discomfort

PurposeTo investigate the ocular inflammatory response, using clinical and immunological techniques, in people experiencing contact lens (CL) discomfort.MethodsThis study involved 38 adults who were full-time, silicone-hydrogel CL wearers. Participants were categorized into groups based upon a validated CL dry-eye questionnaire (CLDEQ-8) (n = 17 ‘asymptomatic’, CLDEQ-8 score <9; n = 21 ‘symptomatic’, CLDEQ-8 score ≥13). Examinations were performed at two visits (one with, and one without, CL wear), separated by one-week. Testing included: tear osmolarity, ocular redness, tear stability, ocular surface staining, meibography, tear production and tear collection. Tear osmolarity was taken from the inferior-lateral and superior-lateral menisci. The ‘Inferior-Superior Osmotic Difference’, I-SOD, was the absolute osmolarity difference between these menisci. Concentrations of seven cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-gamma, TNF-alpha) were assayed from basal tears using multiplex cytometric bead array.ResultsAt baseline, there was no significant difference in key clinical signs between asymptomatic and symptomatic CL wearers (p > 0.05). The I-SOD was greater in symptomatic than asymptomatic CL wearers (23.1 ± 2.6 versus 11.3 ± 1.4 mOsmol/L, p = 0.001). People experiencing CL discomfort had higher tear IL-17A (122.6 ± 23.7 versus 44.0 ± 10.0 pg/mL, p = 0.02) and reduced tear stability (6.3 ± 1.1 versus 10.4 ± 1.6 s, p = 0.03) after several hours of CL wear. Tear IL-17A levels correlated with both the I-SOD (r = 0.43, p = 0.01) and CLDEQ-8 score (r = 0.40, p = 0.01).ConclusionsCL discomfort occurs in individuals having no clinical dry eye signs, and is associated with higher tear levels of the pro-inflammatory cytokine IL-17A. These findings support an association between the discomfort response and low-grade, ocular surface inflammation.     

地夸磷索钠联合玻璃酸钠改善配戴角膜塑形镜后的泪膜稳定性

目的：探究地夸磷索钠滴眼液联合玻璃酸钠滴眼液对改善角膜塑形镜配戴后的泪膜稳定性的作用。

方法：前瞻性研究。选取2022-03/08于安徽爱尔眼科医院门诊就诊的初次配戴角膜塑形镜患者82例82眼(均取右眼数据),根据随机数字表法分为玻璃酸钠组(玻钠组)30眼、地夸磷索钠组(地夸组)24眼和地夸磷索钠联合玻璃酸钠组(联合组)28眼,各组患者均配戴同一品牌的角膜塑形镜。每位患者分别在配戴角膜塑形镜前,配戴后1 d,1 wk,1 mo进行非接触式泪膜破裂时间(NIBUT)、非接触式泪河高度(NITMH)和脂质层厚度检查,并记录患者是否有角膜点染。

结果：联合组与地夸组治疗1 mo的NITMH与NIBUT较配戴前升高(均P<0.05)。配戴1 mo,联合组的NIBUT和NITMH分别为19.74±3.29 s和0.30±0.05 mm,均优于地夸组(NIBUT：16.09±2.98 s,NITMH：0.22±0.08 mm)和玻钠组(NIBUT：15.67±3.90 s,NITMH：0.22±0.04 mm)(均P<0.01)。各组间脂质层厚度均无明显差异(均P>0.05)。各组患者角膜点染发生率无明显区别(P>0.05)。

结论：地夸磷索钠滴眼液联合玻璃酸钠滴眼液在配戴角膜塑形镜后1 mo对改善NIBUT和NITMH有更佳的效果,有效提高配戴角膜塑形镜患者的泪膜稳定性。     

Effect of hydrogel lens wear on the major tear proteins during extended wear

Purpose: The purpose of the present study was to determine whether contact lens wear disturbed the levels of tear proteins and to further determine whether this was a transient or continuous disruption. Methods: Lactoferrin, lysozyme and albumin were quanti-tated from tears of neophyte patients and were compared with the levels of these proteins in contact lens wearers after one and six nights and 6 months of extended wear The quantitation of these tear proteins was performed by sandwich ELISA and turbidimetric assay. Results: Results showed that there were no statistically significant changes in the concentration of any of the proteins investigated. Conclusions: Extended wear of hydrogel lenses does not appear to alter the concentration of the major tear film proteins, indicating that the tear film is constantly replenished to maintain protein levels, which are depleted due to protein adsorption to the lens surface.     

Epithelial split associated with wear of a silicone hydrogel contact lens.

PURPOSE: To describe the appearance and management of a superior epithelial arcuate lesion (SEAL) observed in association with the wear of a silicone hydrogel lens. METHODS: We present a case of a 30-year-old male who presented with a SEAL after 4 months of wear of a silicone hydrogel lens on a 30-day extended wear schedule. Bacteriological examination of the lenses and ocular adnexa was conducted at the time of the event. The clinical presentation and management are presented and compared to a review of cases associated with hydrogel lenses. RESULTS: The patient presented with symptoms of mild irritation. A linear splitwas noted in the superior peripheral cornea of the affected eye and was associated with limbal injection, stromal infiltrates, and fluorescein staining. Normal ocular biota was recovered from the lenses and eyelids of both eyes. Visual acuity remained unchanged and the lesion resolved following prophylactic treatment and discontinuation of lens wear for 8 days. CONCLUSIONS: The diagnosis and management of this SEAL case in a silicone hydrogel lens wearer mirrored that of previous events associated with hydrogel lenses. The possible etiologies of SEAL in this case are discussed and include mechanical irritation and dehydration of the lens surface.     

The relationship between long-term contact lens wear and corneal thickness.

PURPOSE: The purpose of this study is to assess the effects of long-term contact lens wear on corneal thickness and to compare differences based on rigid versus soft lens material. METHODS: This analysis included scanning slit topographic imaging (Orbscan, Bausch & Lomb, Rochester, NY) performed on 124 consecutive patients (248 eyes), who underwent comprehensive evaluations in consideration of refractive surgery by one surgeon. RESULTS: Sixty-two 62 patients (124 eyes) who had not previously worn contact lenses had a least-squares mean pachymetry of 546.4 microm +/-3.5 SE. Thirty-nine patients (78 eyes) who had previously worn soft contact lenses for an average of 16 years had a least-squares mean pachymetry of 543.2 microm +/-3.8 SE. Twenty-three patients (46 eyes) who had worn rigid contact lenses for an average of 19 years had a least-squares mean pachymetry of 509.4 microm +/-6.9 SE. Mean pachymetry differed significantly between eyes wearing rigid lenses versus no lenses (P<0.0001) and between eyes wearing rigid lenses versus soft lenses (P=0.0002). CONCLUSION: Long-term rigid contact lens wear is associated with a decrease in the average central-corneal thickness (CCT) by an average of 37 microm, in this group of otherwise healthy eyes, compared to no contact lens wear. Long-term soft contact lens wear did not appear to significantly change corneal thickness compared to no contact lens wear. Caution should be exercised when screening patients with a history of long-term rigid contact lens wear for possible excimer-laser photoablative correction.     

Environmental influences on hydrogel lens dehydration and the postlens tear film

The fitting characteristics of thin, high-water-content hydrogel lenses are influenced by variations in postlens tear film morphology; however, the determinants of postlens tear film morphology have not been fully established. We tested the hypothesis that increased lens dehydration due to evaporation at the lens front surface may cause postlens tear film depletion by using a randomized, double-masked study design. Subjects wore high-water-content lenses for 10- and 40-minute periods in a light breeze and in still air. Postlens tear film appearances in specular reflection were categorized as amorphous, faint colored, or colored, where the colored patterns represented a progressive thinning of the postlens tear film. The hydration of both surfaces of each lens was recorded before and after wear with a handheld refractometer. For both wearing periods, the forced air condition was associated with a greater proportion of faint colored and colored postlens tear film appearances compared with the still air condition (Wilcoxon matched-pairs signed-ranks test, p < 0.05). Hydration gradients between the surfaces of the lenses suggested a flow of water from the postlens tear film to the lens front surface during wear. This study has demonstrated that the postlens tear film of a high-water-content lens can be depleted by ambient air flow, and this may contribute to changes in lens fitting during normal wear.