Months Of Contact Lens Wear Research Articles

Analysis of Treatment Discontinuation in Orthokeratology: Studying Efficacy, Safety, and Patient Adherence Over Six Months.

This study aimed to evaluate the efficacy, safety, and participant compliance of orthokeratology treatment for the correction of myopic refractive errors over a six-month prospective study and to define the potential reasons for early treatment discontinuation. A total of 32 participants with low-to-moderate myopia were fitted with the spherical model of corneal refractive therapy (CRT) orthokeratology lenses (Paragon Vision Sciences) and followed over six months, with specific attention to alterations in refractive error, corneal topography, and epithelial thickness. Concurrently, participant feedback and reasons for any treatment discontinuation were documented. Significant changes in refractive error and in corneal topography were observed, with approximately 50% of the refractive error being corrected on the first night of use and 100% by the first two weeks ( P <0.001). Central epithelial thickness experienced substantial thinning, reducing to 15.65±4.49 μm (67.38%) ( P <0.001) after 6 months of lens use. Six participants withdrew from this study for varied reasons, including unmet visual expectations and difficulty adhering to the lens-wearing regimen. Notably, the dropout group exhibited higher baseline low-order aberrations and less prolate corneas than those who persisted with the treatment ( P <0.05). Orthokeratology with CRT is efficacious and safe for the correction of low-to-moderate myopia in adults, but a portion of patients discontinue the treatment in the first 6 months of contact lens wear. Special care should be taken when recommending orthokeratology in patients with higher levels of myopia and corneas with less prolate shape, providing more realistic expectations and even changing to dual axis or more sophisticated designs.

Refitting contact lens dropouts into a modern daily disposable contact lens.

To determine the number of previous contact lens (CL) wearers who could be comfortably refitted into delefilcon A (DAILIES TOTAL1®) CLs. This was a 6-month, three-visit study that recruited subjects who discontinued CLs within the past 2 years because of discomfort or dryness symptoms. Subjects were required to have Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire scores ≤3 and to be able to wear spherical study CLs. Subjects were asked to complete a ±50 comfort visual analogue scale (VAS) at 1 month and a Likert questionnaire after 1 and 6 months of CL wear to understand the subjects' CL experience. All 60 subjects who were fitted with the study CLs were still wearing them after 1 month, while one subject had dropped out by 6 months. Subjects had a median (interquartile range) age of 24.0 (7.0) years (71.7% female). They reported a median VAS score of 44.0 (8.0) units at the 1-month visit, with all reporting a comfortable score. At the 1-month/6-month visits, 98.3%/93.2%, 86.5%/78.0% and 93.2%/91.5% of subjects responded that they were very satisfied or satisfied with their vision, their end-of-day CL comfort and overall CL comfort, respectively. The same subjects responded that they were very likely or likely to continue to wear the study CLs at 1 (89.6%) and 6 months (80.7%) and to recommend the study CLs to a friend at 1 (98.3%) and 6 months (93.2%). The results suggest that when encountering a CL dropout, a practitioner could educate a patient about trying an alternative CL and consider delefilcon A lenses as an option.

Tear Film Surface Quality in Modern Daily Disposable Contact Lens Wear.

As reported previously, tear film surface quality (TFSQ) should be considered in contact lens (CL) fitting. This study followed noninvasive keratograph tear film break-up time (NIKBUT) in CL wearers for 12 months to validate its clinical utility in predicting CL performance. Fifty-five subjects (M/F=17/38) aged 26±4 years were prescribed silicone hydrogel or hydrogel CLs. The study included baseline measurements without CLs; 2 visits for CL fitting and control; follow-up after 3, 6, and 12 months of CL wear; and postwear visit without CLs. Ocular Surface Disease Index (OSDI), 8-Item Contact Lens Dry Eye Questionnaire (CLDEQ-8), first and mean NIKBUT (F/M-NIKBUT), fluorescein tear film break-up time (FBUT), and ocular surface staining were evaluated. Post hoc analysis of each pair of visits showed differences between baseline and all CL visits for F-NIKBUT, M-NIKBUT, FBUT, and corneal staining. No difference was reported in symptoms. In addition, differences between baseline and postwear visits were noted in OSDI, M-NIKBUT, FBUT, and corneal staining, with three of the latter parameters showing a downward trend. No changes in TFSQ and symptoms were reported over 12 months. Introducing NIKBUT as part of routine CL fitting is advised to improve CL fit and predict success.

A 12-month Prospective Study of Tear Osmolarity in Contact Lens Wearers Refitted with Daily Disposable Soft Contact Lenses.

Tear osmolarity has been reported as one of the best diagnostic tests for dry eye disease and its management. Contact lens wear is thought to influence tear homeostasis. Understanding how regular wear of contact lenses and their type affect tear osmolarity is important. The purpose of this study was to assess changes in tear osmolarity and ocular symptoms over a period of 12 months following refitting contact lens wearers with daily disposable contact lenses. Fifty subjects aged (mean ± SD) 26 ± 4 years were refitted with either silicone-hydrogel (delefilcon A, SiHy, n = 34) or hydrogel (omafilcon A, Hy, n = 16) daily disposable soft contact lenses. Study included seven visits: baseline measurements without contact lenses; two visits for contact lens fit and selection; follow-up measurements after 3, 6, and 12 months of contact lens wear; and a post-study visit without contact lenses. Lens type selection was based on a set of objective measurements. Subjects were instructed to follow strict wearing rules. Impedance-based osmometer was used to collect samples from the lower tear meniscuses. The Ocular Surface Disease Index (OSDI) and the eight-item Contact Lens Dry Eye Questionnaire were used to assess subject-reported ocular symptoms and contact lens discomfort, respectively. Downward trend of tear osmolarity was noted over the time course of study. Statistically significant differences were noted in tear osmolarity (Friedman test, χ = 21.91 [P < .001], and χ = 13.89 [P = .003]) for the right and left eyes, respectively. A statistically significant decrease in tear osmolarity was apparent only for initially symptomatic subjects (for OSDI ≥13: χ = 26.25, P < .001; for OSDI <13: χ = 5.65, P = .13). Statistically significant differences were not noted in OSDI and the eight-item Contact Lens Dry Eye Questionnaire between the baseline and 12-month visit (χ = 5.92 [P = .12] and R = 0.015 [P = .87], respectively). There was a difference between baseline and post-study visits (P = .002) in OSDI, showing lower score at the latter visit. Refitting with daily disposable contact lenses was demonstrated to lower tear osmolarity.

Contrast sensitivity function with soft contact lens wear

PurposesTo compare contrast sensitivity function (CSF) with soft contact lens (SCL) and spectacles wear. To investigate the effect of a three-month period of SCL wear on CSF. MethodsForty-seven myopic subjects with no history of contact lens (CL) wear were included in this longitudinal prospective study. CSF was measured with spectacles using the CSV-1000 (VectorVision, Greenvile, OH). Subsequently, subjects were fitted with a daily disposable lens (Nelfilcon-A, Stenofilcon-A or Nesofilcon-A) in one eye and a monthly disposable lens (Lotrafilcon-B, Comfilcon-A or Balafilcon-A) in the other eye and wore the same type of CLs for three months. CSF was measured again on the same day and after three months wearing CLs. Differences in CSF with spectacles and CLs on baseline and changes to CSF after three months of CLs wear were assessed. The effect of lens materials and wearing modality on CSF change was also investigated. ResultsCSF was higher with CLs in comparison to the values with spectacles for spatial frequencies of 3, 6 and 12 cycles per degree (cpd) (p<0.05) while there was no difference for spatial frequency of 18 cpd (p=0.114). No significant difference was found in the CSF with CLs between baseline and after three months of lens wear (p>0.05). There was no difference in CSF between hydrogel and silicone CLs as well as when comparing daily with monthly wear CLs (p>0.05). ConclusionCSF is better with CLs than with spectacles. CSF values with CL are similar between baseline and after 3 months of lens wear.

Evaluation of the Tear Function Tests and the Ocular Surface in First-Time Users of Silicone Hydrogel Contact Lenses

ABSTRACTPurpose: To evaluate the effects of three different silicone hydrogel contact lenses (SHCL), (balafilcon A, senofilcon A, and comfilcon A) on tear function tests, corneal thickness, and ocular surface cytology in first time contact lens users.Materials and methods: In this prospective study, 120 eyes of 60 subjects were evaluated. Balafilcon A users were designated as group 1, senofilcon A users as group 2, and comfilcon A users as group 3. In all cases, before and after 6 months of contact lens wear, ocular surface disease index score (OSDI), tear breakup time (TBUT), Schirmer 1 test, central corneal thickness (CCT), central corneal epithelium thickness (CCET), and conjunctival impression cytology samples were evaluated.Results: In group 1, 40 eyes of the 20 patients, in group 2, 40 eyes of the 20 patients, and in group 3, 40 eyes of the 20 patients were evaluated. The mean OSDI scores did not differ between the three groups after contact lens wear (p > 0.05). In group 1 and group 2, significant decrease was found in the mean TBUT 6 months after contact lens wear (p = 0.04, p < 0.001, respectively). In group 3, after 6 months of contact lens wear, the mean Schirmer 1 tear test was decreased significantly (p = 0.021). In all 3 groups, no significant change was observed in the mean CCT and CCET after contact lens wear (p > 0.05). After 6 months, the morphological changes in temporal and superior conjunctival epithelial cells were found to be significant in all groups (p < 0.001).Conclusion: Six months after SHCL wear, marked morphological changes occurred in the conjunctival epithelium. Tear function tests were also affected, while corneal thickness did not show any significant difference.

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

BackgroundThe 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.MethodsThis 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.ResultsGoblet cell density reduced significantly by 85 ± 151 cells/mm2 (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).ConclusionThree 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.

Time Course of Changes in Goblet Cell Density in Symptomatic and Asymptomatic Contact Lens Wearers.

To investigate longitudinal changes in goblet cell density (GCD) in contact lens (CL) wearers who do and do not develop symptoms of dry eye (DE). Sixty healthy individuals fitted with daily disposable hydrogel CLs and 23 age-balanced non-CL-wearing controls underwent assessment using the 5-item dry eye questionnaire, noninvasive tear film break-up time measurement, ocular surface assessment, and phenol red thread test evaluation. Laser scanning confocal microscopy (LSCM) and conjunctival impression cytology (CIC) were used to assess GCD at baseline and follow-up visits at 1 week and 1 and 6 months. After 1 week, all CL wearers were categorized as those who were and were not symptomatic based on responses to the CL dry eye questionnaire-8 (CLDEQ-8). A linear mixed-model was used to examine changes in GCD over time. The global mean GCD of the 83 participants at baseline (before CL wear) was 476 ± 41 and 467 ± 52 cells/mm2 using LSCM and CIC, respectively. After 6 months of CL wear, GCD was reduced by approximately 13% and 29% in asymptomatic (N = 29) and symptomatic (N = 17) CL wearers (all P < 0.001), respectively, observed with both LSCM and CIC. Contact lens wear induces a reduction of GCD over 6 months, which is exacerbated in those with DE symptoms. Either LSCM or CIC can be used to assess GCD in the conjunctiva.

Disinfectant efficacy of soft contact lens care system containing povidone iodine

Disinfectant efficacy of soft contact lens care system containing povidone iodine

Comparison of the effects of first and second generation silicone hydrogel contact lens wear on tear film osmolarity.

To compare the effects of first and second generation silicone hydrogel (SiH) contact lens wear on tear film osmolarity. The healthy subjects who have never used contact lenses before were enrolled in the study. Tear film osmolarity values of 16 eyes (group 1) who wore first generation SiH contact lenses were compared with those of 18 eyes (group 2) who wore second generation SiH contact lenses after three months follow-up. Before contact lens wear, tear film osmolarity of groups 1 and 2 were 305.02±49.08 milliosmole (mOsm) and 284.66±30.18mOsm, respectively. After three months of contact lens wear, osmolarity values were found 317.74±60.23mOsm in group 1 and 298.40±37.77mOsm in group 2. Although osmolarity values for both groups of SiH contact lens wear after three months periods were slightly higher than before the contact lens wear, the difference was not statistically significant. Contact lens wear may cause evaporation from the tear film and can increase tear film osmolarity leading to symptoms of dry eye disease. In the current study, there is a tendency to increase tear film osmolarity for both groups of SiH contact lens wear, but the difference is not statistically significant.

Visual performance comparison between contact lens‐based pinhole and simultaneous vision contact lenses

BackgroundThe aim was to evaluate the visual performance provided with a contact lens‐based pinhole design against a simultaneous vision multifocal contact lens.MethodsIn a cross‐over study at the University of Valencia, 22 presbyopic patients were evaluated using an artificial pupil fitted on the non‐dominant eye and the simultaneous vision PureVision Multifocal contact lenses. After one month of contact lens wear, binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance contrast sensitivity, binocular near contrast sensitivity, and stereoacuity were measured, under photopic conditions (85-cd/m2). In addition, binocular distance visual acuity and binocular distance contrast sensitivity were examined under mesopic conditions (5-cd/m2).ResultsMean binocular distance visual acuity for pinhole and PureVision Multifocal were 0.02 ± 0.04 and 0.01 ± 0.04 logMAR under photopic conditions and 0.16 ± 0.06 and 0.12 ± 0.04 logMAR for binocular near visual acuity under mesopic conditions, respectively. No statistically significant differences were found between both types of lenses at distance for both lighting levels and intermediate distances (p > 0.05). There was a significant difference at near vision under photopic conditions (p = 0.03). Binocular distance contrast sensitivity revealed statistically significant differences between the pinhole system and PureVision Multifocal for six and 12-cpd (cycles per degree) spatial frequencies at the two luminance levels, while for near vision, differences were also significant for 18-cpd. Stereoacuity was better with PureVision Multifocal (127 ± 49.3 seconds of arc) compared with the pinhole lens (220.2 ± 32.3 seconds of arc, p = 0.004).ConclusionPinhole and PureVision Multifocal contact lenses provide good binocular vision for distance and functional intermediate vision. Although it was better with the PureVision Multifocal, near vision was not satisfactory for either of the two contact lens options.

Differential Gel Electrophoresis of the Tear Proteome

This study evaluates the use of differential gel electrophoresis (DIGE) for tear analysis and applies this technique to establish the effect of extended contact lens wear on the tear proteome. Flush tears were collected from nine healthy non-contact lens wearers at baseline, during the first day, and after 1 month of contact lens wear. Participants wore AIR OPTIX on an extended wear (EW) schedule. Tears were collected at mid-day and upon waking and analyzed for concentrations of total protein using the bicinchoninic acid assay method. DIGE was then performed to detect biomarkers likely to be affected by contact lens wear. Technique variability, physiological variability, and the effect of EW were established. Proteins with significantly changed abundance during lens wear were cut and identified with mass spectrometry. Both Cy3 and Cy5 identified the same proteins relative to Cy2 with the highest fold difference of 4.4. The proteome varied by 3% at the same time point, with a significant increase in protein spots found between mid-day (257) and upon awakening (298). With EW, of the 311 proteins spots identified upon awakening, 15 differed significantly. Of the five differences between baseline and the first night of EW, all were greater at baseline. Of the differences between baseline and 1 month, six were greater at 1 month and four were greater at baseline. DIGE is a repeatable proteomic technique capable of determining differences in the tear proteome. The extent of the participants' experience with lens wear is an important factor to consider when analyzing the tears from lens wearers, as neophytes appear to differ from those with experience.

Jupiter Scleral Lenses in the Management of Chronic Graft Versus Host Disease

To describe the use of the Jupiter scleral contact lens (Medlens Innovations, Front Royal, VA or Essilor Contact Lens, Inc., Dallas, TX) in the management of ocular manifestations of chronic graft versus host disease (cGVHD). This study is a retrospective case series. Five consecutive patients with severe keratoconjunctivitis sicca (KCS) associated with cGVHD that could not be adequately managed with conventional therapy were evaluated for scleral contact lens wear between January and December 2007. All patients were evaluated with lenses from the standard 18.2 mm Jupiter B diagnostic fitting set. If lenses of standard design failed to provide adequate fit, custom lenses were designed. Three outcome measures were evaluated: the patient's ability to tolerate and successfully handle the lenses, improvement in symptoms of KCS, and improvement in visual acuity. All 5 patients (10 eyes) were successfully fit with Jupiter scleral lenses. Six eyes of 3 patients were successfully fit with lenses of standard design. Standard parameters were altered to achieve adequate fit in 4 eyes of 2 patients. All patients reported subjective improvements in comfort with Jupiter scleral lenses, and best-corrected vision improved in 7 of the 10 eyes fit within the first several months of contact lens wear. The remaining 3 eyes maintained the visual acuity measured before scleral lens wear (20/20 in 2 eyes, 20/40 in 1 eye). Duration of follow-up ranged from 4 to 14 months. Jupiter scleral lenses can relieve symptoms of KCS and may improve vision in patients with cGVHD.

The effect of successful contact lens wear on mucosal immunity of the eye

Objective This study aimed to assess the effect of contact lens wear on the mucosal defenses of the outer eye against infection. Design A case-controlled study of daily contact lens wearers in their initial 6 months of contact lens wear. Participants Contact lens wearers (mean age, 23.1 years; 47 subjects) were compared with age-matched control subjects (mean age, 24.7 years; 44 subjects). Intervention Outer eye defenses were studied by assay of tear constituents and quantitative conjunctival microbiology. Main outcome measures Antimicrobial activity of tears was studied by assay of total immunoglobulin A (IgA), IgA isotype-specific antibodies reactive with Escherichia coli, Haemophilus influenzae, Staphylococcus epidermidis, albumin and lysozyme, and the ocular surface microbial load determined using quantitative microbiology of the conjunctival sac. Results The IgA isotype-specific antibodies reactive with E. coli ( P = 0.03) and S. epidermidis ( P = 0.068) were lower in contact lens wearers, but antibody:albumin ratios were not significantly different in the two groups. Contact lens wear also had no significant effect on tear IgA, albumin, or lysozyme or its ratios with albumin. Bacterial numbers and colonization rates for coagulase-negative staphylococci were greater in contact lens wearers than in age-matched control subjects. Corynebacterium sp. and non-Enterobacteriaceae ( P = 0.007) were isolated more frequently and in greater numbers from contact lens wearers. Colonization rates were increased for Corynebacterium sp., but non-Enterobacteriaceae were transient. In both daily contact lens wearers and age-matched control subjects, most conjunctival flora were transient rather than colonizing, and no subject developed an outer eye infection during the study. Conclusion These results suggest that daily contact lens wear does not significantly alter the mucosal defenses of the outer eye that function to eliminate organisms from the conjunctival sac and prevent outer eye infection.

Use of contact lenses by firefighters: Part 2. Clinical evaluation

Contact lenses can be worn in a variety of environmental conditions and do not increase the wearers risk of injury. In many situations they offer significant corneal protection. Currently firefighters are prohibited from using contact lenses. To evaluate whether contact lenses are a safe form of visual correction 50 firefighters were fitted, and examined after 1, 4 and 10 months of contact lens wear. Twenty-nine were fitted with soft contact lenses, and 21 with rigid gas permeable contact lenses. Statistically significant increase in lid sulcus hyperaemia was found in both the SCL and RGPCL groups (P < 0.01, P = 0.02, respectively), as well as an increase in hyperaemia of the vertical quadrant of the bulbar conjunctivae (P = 0.01, P = 0.02, respectively). In addition the RGPCL group showed a statistically significant increase in hyperaemia of the lateral portion of the bulbar conjunctivae (P < 0.01), consistent with exposure epitheliopathy. The SCL group showed statistically significant increase in corneal staining in the vertical quadrant for all visits (P = 0.02, P = 0.01, P = 0.02 for all visits, respectively), indicative of lens dehydration. These findings although clinically significant are not unique to firefighting, and are found within a "normal" population of contact lens wearers. In conjunction with questionnaire data (Owen et all, 1996) we conclude that soft contact lenses can be worn safely by firefighters without additional risk.

Use of contact lenses by firefighters. Part 1: Questionnaire data

The use of contact lenses by firefighters is currently prohibited. However, many firefighters may benefit from this form of visual correction, without predisposing themselves to additional risk. Visual benefits gained by contact lens wear may increase a firefighter's safety. To determine if it is safe to allow firefighters to use contact lenses 29 were fitted with soft contact lenses and 21 with rigid gas permeable contact lenses. Questionnaires were completed prior to fitting, after 1, 4 and 10 months of contact lens wear. Both soft contact lens (SCL) wearers, and rigid gas permeable contact lens (RGPCL) wearers showed a statistically significant reduction in the frequency with which they experienced irritable foreign bodies and irritant fumes in the eyes, compared to not wearing contact lenses. Firefighters felt that their performance on the fireground had been improved by the use of contact lenses. SCL wearers also benefited from a reduction in the frequency with which they experienced watery eyes and ocular discomfort. There were significantly fewer problems encountered with SCL wearers than RGPCL wearers. The frequency with which firefighters experienced lenses falling out, lens displacement, watery eyes, ocular discomfort, and operational difficulties was significantly less for the SCL group than the RGPCL group. SCL appear to offer considerable benefits for firefighters with refractive error, but their use cannot be sanctioned without assessment of their effect on the ocular adnexa.

Use of contact lenses by firefighters. Part 1: Questionnaire data

The use of contact lenses by firefighters is currently prohibited. However, many firefighters may benefit from this form of visual correction, without predisposing themselves to additional risk. Visual benefits gained by contact lens wear may increase a firefighter's safety. To determine if it is safe to allow firefighters to use contact lenses 29 were fitted with soft contact lenses and 21 with rigid gas permeable contact lenses. Questionnaires were completed prior to fitting, after 1, 4 and 10 months of contact lens wear. Both soft contact lens (SCL) wearers, and rigid gas permeable contact lens (RGPCL) wearers showed a statistically significantly reduction in the frequency with which they experience irritable foreign bodies and irritant fumes in the eyes, compared to not wearing contact lenses. Firefighters felt that their performance on the fireground had been improved by the use of contact lenses. SCL wearers also benefited from a reduction in the frequency with which they experienced watery eyes and ocular discomfort. There were significantly fewer problems encountered with SCL wearers than RGPCL wearers. The frequency with which firefighters experienced lenses falling out, lens displacement, watery eyes, ocular discomfort, and operational difficulties was significantly less for the SCL group than the RGPCL group. SCL appear to offer considerable benefits for firefighters with refractive error, but their use cannot be sanctioned without assessment of their effect on the ocular adnexa.

A new computer assisted objective method for quantifying vascular changes of the bulbar conjunctivae

A novel computer software method was used to quantify the conjunctival plexus on the scleral background for measurement of the vascular surface area from photographs. A previously described method was used (Palmer, J. R., Owen, C. G., Ford, A. M., Jacobson, R. E. and Woodward, E. G. (1996). Optimal photographic imaging of the bulbar conjunctival vasculature. Ophthal. Physiol. Opt. 16, 144–149) to optimise photographic imaging of the bulbar conjunctival vasculature by increasing the information content in the image. Repeatability of this technique was evaluated. Twenty subjects (20 eyes) free from ophthalmological and systemic abnormality were examined on two separate occasions. The maximum 95% confidence limits for repeatability are +8.58/ −3.95%. For 10 consecutive estimates of vascularity the maximum 95% confidence interval lie between ± 6.54%. To evaluate the technique the lateral-bulbar conjunctivaein 10 soft (SCL) and 10 rigid gas permeable contact lens (RGPCL) wearers during the first 10 months of contact lens wear, were assessed and compared with subjective grading of hyperaemia. The new method showed sufficient sensitivity in detecting increased hyperaemia in the RGPCL wearing group and demonstrated statistically significant change. Subjective graded assessment of vascularity (using established classifications) detected increased hyperaemia, however, this was not statistically significant. Conjunctival vasculature is a dynamic structure and a source of valuable quantitative information where the ocular environment is varied, or where the ocular surface is affected by disease. Hence it is worthy of further investigation. A simple inexpensive method of computer assisted determination of vascularity is described.

A new computer assisted objective method for quantifying vascular changes of the bulbar conjunctivae

SummaryA novel computer software method was used to quantify the conjunctival plexus on the scleral background for measurement of the vascular surface area from photographs. A previously described method was used (Palmer, J. R., Owen, C. G., Ford, A. M., Jacobson, R. E. and Woodward, E. G. (1996). Optimal photographic imaging of the bulbar conjunctival vasculature. Ophthal. Physiol. Opt.16, 144–149) to optimise photographic imaging of the bulbar conjunctival vasculature by increasing the information content in the image. Repeatability of this technique was evaluated. Twenty subjects (20 eyes) free from ophthalmological and systemic abnormality were examined on two separate occasions. The maximum 95% confidence limits for repeatability are +8.58/−3.95%. For 10 consecutive estimates of vascularity the maximum 95% confidence interval lie between ±6.54%. To evaluate the technique the lateral‐bulbar conjunctivaein 10 soft (SCL) and 10 rigid gas permeable contact lens (RGPCL) wearers during the first 10 months of contact lens wear, were assessed and compared with subjective grading of hyperaemia. The new method showed sufficient sensitivity in detecting increased hyperaemia in the RGPCL wearing group and demonstrated statistically significant change. Subjective graded assessment of vascularity (using established classifications) detected increased hyperaemia, however, this was not statistically significant. Conjunctival vasculature is a dynamic structure and a source of valuable quantitative information where the ocular environment is varied, or where the ocular surface is affected by disease. Hence it is worthy of further investigation. A simple inexpensive method of computer assisted determination of vascularity is described.

Transient decrease of secretory IgA in tears during rigid gas permeable contact lens wear.

Decreased humoral defense mechanisms may be involved in the occurrence of keratic ulcerations after contact lens wear. To investigate the effect of contact lens wear on tear protein composition a prospective study was performed whereby tears were collected with Schirmer papers from 42 healthy individuals, before and at varying times after contact lens wear. Tear proteins were quantitated using HPLC analysis. Analysis of tear fluid by HPLC is a rapid and simple technique to detect the major tear proteins. Four separate peaks containing respectively IgA, lactoferrin, TSPA and lysozyme can easily be identified. The results show that the mean relative level of secretory IgA in the collected tear samples decreased significantly after the first months of contact lens wear but was not significantly altered after one year. The decrease in IgA was accompanied by a significant increase in the relative amount of lysozyme, whereas the levels of lactoferrin and TSPA remained the same. Certain individuals showed a marked decrease in their tear secretory IgA levels after wearing the lenses for more than one year. Future studies will clarify whether such individuals are at higher risk to develop corneal complications.