Clinical grading of the upper palpebral conjunctiva of non-contact lens wearers

CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia). However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation. In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.

In vivo Confocal Microscopy Evaluation of Meibomian Gland Dysfunction in Dry Eye Patients with Different Symptoms

Background:

Dry eye patients suffer from all kinds of symptoms. Sometimes, the clinical signs evaluation does not disclose any obvious difference in routine examination; in vivo confocal microscopy (IVCM) is a powerful tool for ocular surface disease. This study aimed to clarify meibomian gland (MG) alterations in dry eye patients with different symptoms and to compare the findings using IVCM.

Methods:

A total of sixty patients were recruited, all subjected to Ocular Surface Disease Index (OSDI) and Salisbury Eye Evaluation Questionnaire (SEEQ), and questionnaires for the assessment of dry eye symptoms before clinical sign examinations were given to the patients. Finally, IVCM was applied to observe MG's structure. Statistical analysis was performed using the t-test, Mann-Whitney U-test and Spearman correlation analysis. The differences were statistically significant when P < 0.05.

Results:

In the severe symptom group, OSDI and SEEQ scores were significantly higher (P < 0.05) compared with the mild symptoms group. All other clinical sign examinations had no statistical difference in the two groups (P > 0.05). However, all the IVCM-observed data showed that patients with severe symptoms had more significant fibrosis in MG (acinar unit area 691.87 ± 182.01 μm² for the severe, 992.17 ± 170.84 μm² for the mild; P < 0.05) and severer decrease in the size of MG acinar units than those observed in patients with mild symptoms (MG acinar unit density [MGAUD] 70.08 ± 18.78 glands/mm², MG acinar unit longest diameter [MGALD] 51.50 ± 15.51 μm, MG acinar unit shortest diameter [MGASD] 20.30 ± 11.85 μm for the severe, MGAUD 89.53 ± 39.88 glands/mm², MGALD 81.57 ± 21.14 μm, MGASD 42.37 ± 14.55 μm for the mild; P < 0.05). Dry eye symptoms were negatively correlated with MG confocal microscopic parameters and positively correlated with conjunctival inflammatory cells and Langerhans cells (P < 0.05).

Conclusions:

IVCM application provides a strong support to differentiate dry eye patients with different symptoms: meibomian gland dysfunction (MGD) plays a pivotal role in dry eye aggravation, and using IVCM to observe MG fibrosis, changes in size and density of MG as well as status of inflammation cells can help not only correctly diagnose the type and severity of dry eye, but also possibly prognosticate in routine eye examination in the occurrence of MGD.

Anterior eye health recording

AIMS

To survey eye care practitioners from around the world regarding their current practice for anterior eye health recording to inform guidelines on best practice.

METHODS

The on-line survey examined the reported use of: word descriptions, sketching, grading scales or photographs; paper or computerised record cards and whether these were guided by proforma headings; grading scale choice, signs graded, level of precision, regional grading; and how much time eye care practitioners spent on average on anterior eye health recording.

RESULTS

Eight hundred and nine eye care practitioners from across the world completed the survey. Word description (p<0.001), sketches (p=0.002) and grading scales (p<0.001) were used more for recording the anterior eye health of contact lens patients than other patients, but photography was used similarly (p=0.132). Of the respondents, 84.5% used a grading scale, 13.5% using two, with the original Efron (51.6%) and CCLRU/Brien-Holden-Vision-Institute (48.5%) being the most popular. The median features graded was 11 (range 1-23), frequency from 91.6% (bulbar hyperaemia) to 19.6% (endothelial blebs), with most practitioners grading to the nearest unit (47.4%) and just 14.7% to one decimal place. The average time taken to report anterior eye health was reported to be 6.8±5.7 min, with the maximum time available 14.0±11 min.

CONCLUSIONS

Developed practice and research evidence allows best practice guidelines for anterior eye health recording to be recommended. It is recommended to: record which grading scale is used; always grade to one decimal place, record what you see live rather than based on how you intend to manage a condition; grade bulbar and limbal hyperaemia, limbal neovascularisation, conjunctival papillary redness and roughness (in white light to assess colouration with fluorescein instilled to aid visualisation of papillae/follicles), blepharitis, meibomian gland dysfunction and sketch staining (both corneal and conjunctival) at every visit. Record other anterior eye features only if they are remarkable, but indicate that the key tissue which have been examined.

Prevalence of papillary changes and folliculosis of the palpebral conjunctiva in asymptomatic Chinese children

PURPOSE

To determine the prevalence of papillary changes of the upper palpebral conjunctiva and folliculosis of the lower palpebral conjunctiva in Chinese children with no history of contact lens wear.

METHOD

Ninety-nine subjects (aged 6-15 years old) who were interested in a myopia control study were screened for papillary changes and folliculosis of the palpebral conjunctiva. Photodocumentation was performed under white and blue light (after the application of fluorescein) with a yellow filter and the photographs were graded by a group of practitioners according to a pre-set grading scale. Analysis was performed with the subjects divided into groups according to gender and age.

RESULTS

More than 48% of the subjects had clinically significant (≥Grade 3) papillary changes in the upper palpebral conjunctiva. The prevalence of significant folliculosis in the lower lid was about 33%. The prevalence of significant papillary changes and folliculosis were similar between genders. No differences were observed between younger (age≤10 years old) and older (age>10 years old) in papillary changes but younger subjects showed a higher prevalence of folliculosis.

CONCLUSIONS

The prevalences of clinically significant papillary changes and folliculosis of unknown aetiology are high in Chinese children.

Grading of tarsal conjunctiva of young adults in Malaysia

BACKGROUND

The monitoring and assessment of the upper tarsal conjunctiva can be enhanced by the use of a grading scale. The aim of this study was to categorise the appearance of normal tarsal conjunctiva among young adults in Malaysia using the Institute for Eye Research grading scale and to investigate inter- and intra-observer agreement.

METHODS

The appearance of the upper tarsal conjunctiva of 416 non-contact lens wearing subjects aged between 19 to 24 years was assessed by two separate observers for roughness and redness in three separate zones using the Institute for Eye Research grading scale. The average grade for each zone and overall grade for roughness and redness were calculated. Inter- and intra-observer agreements were analysed.

RESULTS

Subjects were categorised for ethnicity and the roughness and redness were calculated. No significant differences were found between Malay and Chinese eyes (p > 0.05). The average grades for the upper tarsal conjunctiva redness and roughness were 0.90 ± 0.25 and 0.86 ± 0.43, respectively. Significantly higher roughness scores were found in zone 1 compared to the other two zones (p = 0.03). Significant association was also found between tarsal conjunctiva redness and roughness (Spearman ρ= 0.45, p < 0.001). Correlation between redness and roughness with age (p = 0.48, p = 0.65) and gender (p = 0.30, p = 0.79) were not significant. Only 2.2 per cent of subjects had scores higher than 2.0 for roughness or redness. Inter- and intra-observer analysis showed good agreement between two observers during the study.

CONCLUSION

The roughness and redness of normal tarsal conjunctiva among young adults in Malaysia were found to be less than two units. Results of this study might be beneficial in clinical trials using contact lenses where changes in the tarsal conjunctiva are commonly used as an outcome measure.

Objective grading of the anterior eye

PURPOSE

To convert objective image analysis of anterior ocular surfaces into recognisable clinical grades, in order to provide a more sensitive and reliable equivalent to current subjective grading methods; a prospective, randomized study correlating clinical grading with digital image assessment.

METHODS

The possible range of clinical presentations of bulbar and palpebral hyperaemia, palpebral roughness and corneal staining were represented by 4 sets of 10 images. The images were displayed in random order and graded by 50 clinicians using both subjective CCLRU and Efron grading scales. Previously validated objective image analysis was performed 3 times on each of the 40 images. Digital measures included edge-detection and relative-coloration components. Step-wise regression analysis determined correlations between the average subjective grade and the objective image analysis measures.

RESULTS

Average subjective grades could be predicted by a combination of the objective image analysis components. These digital "grades" accounted for between 69% (for Efron scale-graded palpebral redness) and 98% (for Efron scale-graded bulbar hyperaemia) of the subjective variance.

CONCLUSIONS

The results indicate that clinicians may use a combination of vessel areas and overall hue in their judgment of clinical severity for certain conditions. Objective grading can take these aspects into account, and be used to predict an average "objective grade" to be used by a clinician in describing the anterior eye. These measures are more sensitive and reliable than subjective grading while still utilizing familiar terminology, and can be applied in research or practice to improve the detection, and monitoring of ocular surface changes.

Grading static versus dynamic images of contact lens complications

BACKGROUND

This study was conducted to investigate grading performance when estimating the severity of static versus dynamic images of contact lens-related ocular pathology.

METHODS

Thirty-eight subjects used the Efron Grading Scales for Contact Lens Complications to grade the severity of ocular pathological changes depicted in static and dynamic (movie clip) computer-displayed images of each of the following contact lens complications: bulbar conjunctival redness, limbal redness, papillary conjunctivitis, corneal staining, corneal infiltrates and meibomian gland dysfunction. The viewing of static and dynamic images was separated by seven weeks.

RESULTS

Grades assigned to dynamic images were 0.6 and 0.7 grading scale units higher than those assigned to static images for limbal redness and papillary conjunctivitis, respectively (p < 0.0001 for both). No difference was observed for the other four complications. There was an apparent trend for grading variability to be reduced (that is, observers grading in closer agreement) when grading dynamic versus static images.

CONCLUSIONS

Absolute grades based on an assessment of signs of pathology represented in static images may, in some instances, underestimate the true severity of the condition.

Sensitivity and reliability of objective image analysis compared to subjective grading of bulbar hyperaemia

AIMS

To establish the sensitivity and reliability of objective image analysis in direct comparison with subjective grading of bulbar hyperaemia.

METHODS

Images of the same eyes were captured with a range of bulbar hyperaemia caused by vasodilation. The progression was recorded and 45 images extracted. The images were objectively analysed on 14 occasions using previously validated edge-detection and colour-extraction techniques. They were also graded by 14 eye-care practitioners (ECPs) and 14 non-clinicians (NCLs) using the Efron scale. Six ECPs repeated the grading on three separate occasions

RESULTS

Subjective grading was only able to differentiate images with differences in grade of 0.70-1.03 Efron units (sensitivity of 0.30-0.53), compared to 0.02-0.09 Efron units with objective techniques (sensitivity of 0.94-0.99). Significant differences were found between ECPs and individual repeats were also inconsistent (p<0.001). Objective analysis was 16x more reliable than subjective analysis. The NCLs used wider ranges of the scale but were more variable than ECPs, implying that training may have an effect on grading.

CONCLUSIONS

Objective analysis may offer a new gold standard in anterior ocular examination, and should be developed further as a clinical research tool to allow more highly powered analysis, and to enhance the clinical monitoring of anterior eye disease.

How red is a white eye? Clinical grading of normal conjunctival hyperaemia

PURPOSE

To quantify the level of normal bulbar conjunctival hyperaemia using the Cornea and Contact Lens Research Unit (CCLRU) grading scale, and to investigate inter-observer agreement.

METHODS

Bulbar conjunctival hyperaemia was assessed by two trained observers, using the CCLRU grading scale (zero to four units) interpolated into 0.1 increments, on the right eye of 121 healthy, non-contact lens-wearing subjects (male=58, female=63, median age=28 years, range 16-77). The eye was observed using a slit-lamp bio-microscope (x 10 magnification) under diffuse, white illumination. The subject's position of gaze was directed to allow grading of four quadrants: superior, nasal, inferior, and temporal conjunctiva. Bulbar redness was defined as the average of those four grades of conjunctival hyperaemia. A further twenty subjects were recruited to assess inter-observer agreement (male=8, female=12, median age=23 years).

RESULTS

The average bulbar redness was 1.93 (+/-0.32 SD) units. The nasal (2.3+/-0.4) and temporal (2.1+/-0.4) quadrants were significantly redder than the superior (1.6+/-0.4) and inferior (1.7+/-0.4) quadrants (P<0.0001). Males had redder eyes than females by 0.2 units. Inter-observer 95% limits of agreement for bulbar redness was 0.38 units.

CONCLUSIONS

The average bulbar redness of 1.9 units was higher than expected, reflecting the design of the grading scale. A bulbar redness of greater than 2.6 units may be considered abnormal, and a change in bulbar redness of > or =0.4 units may be significant.

Incremental nature of anterior eye grading scales determined by objective image analysis

AIM

To use previously validated image analysis techniques to determine the incremental nature of printed subjective anterior eye grading scales.

METHODS

A purpose designed computer program was written to detect edges using a 3 x 3 kernal and to extract colour planes in the selected area of an image. Annunziato and Efron pictorial, and CCLRU and Vistakon-Synoptik photographic grades of bulbar hyperaemia, palpebral hyperaemia roughness, and corneal staining were analysed.

RESULTS

The increments of the grading scales were best described by a quadratic rather than a linear function. Edge detection and colour extraction image analysis for bulbar hyperaemia (r2 = 0.35-0.99), palpebral hyperaemia (r2 = 0.71-0.99), palpebral roughness (r2 = 0.30-0.94), and corneal staining (r2 = 0.57-0.99) correlated well with scale grades, although the increments varied in magnitude and direction between different scales. Repeated image analysis measures had a 95% confidence interval of between 0.02 (colour extraction) and 0.10 (edge detection) scale units (on a 0-4 scale).

CONCLUSION

The printed grading scales were more sensitive for grading features of low severity, but grades were not comparable between grading scales. Palpebral hyperaemia and staining grading is complicated by the variable presentations possible. Image analysis techniques are 6-35 times more repeatable than subjective grading, with a sensitivity of 1.2-2.8% of the scale.

Clinical monitoring of ocular physiology using digital image analysis

AIM

To examine the use of image analysis to quantify changes in ocular physiology.

METHOD

A purpose designed computer program was written to objectively quantify bulbar hyperaemia, tarsal redness, corneal staining and tarsal staining. Thresholding, colour extraction and edge detection paradigms were investigated. The repeatability (stability) of each technique to changes in image luminance was assessed. A clinical pictorial grading scale was analysed to examine the repeatability and validity of the chosen image analysis technique.

RESULTS

Edge detection using a 3 x 3 kernel was found to be the most stable to changes in image luminance (2.6% over a +60 to -90% luminance range) and correlated well with the CCLRU scale images of bulbar hyperaemia (r=0.96), corneal staining (r=0.85) and the staining of palpebral roughness (r=0.96). Extraction of the red colour plane demonstrated the best correlation-sensitivity combination for palpebral hyperaemia (r=0.96). Repeatability variability was <0.5%.

CONCLUSIONS

Digital imaging, in conjunction with computerised image analysis, allows objective, clinically valid and repeatable quantification of ocular features. It offers the possibility of improved diagnosis and monitoring of changes in ocular physiology in clinical practice.

Experience and training as determinants of grading reliability when assessing the severity of contact lens complications

PURPOSE

A study was conducted to investigate the influence of experience and training on grading reliability when assessing the severity of contact lens complications.

METHODS

Twenty-three optometry students who were unfamiliar with the use of grading scales each used the Efron Grading Tutor computer program to ascertain grading reliability at an 'initial' experimental session and a 'final' session 3 weeks later. Twelve subjects (the 'trained' group) were given a tutorial on grading techniques and were asked to complete two grading exercises between the initial and final sessions. The other 11 subjects (the 'untrained' group) received no such training between the two sessions. Differences in grading reliability between the initial and final grading sessions were evaluated.

RESULTS

Grading reliability was superior (lower) for the combined subject cohort at the final session (mean +/- standard deviation 0.33 +/- 0.12) compared with the initial session (0.46 +/- 0.25) (p = 0.004). However, there was no difference in the improvement in grading reliability between the two groups.

CONCLUSIONS

Grading reliability improves statistically with some experience, although perhaps not to a clinically meaningful extent. No added benefit can be derived from supplemental training.

Validation of computer morphs for grading contact lens complications

Abstract An alternative to the use of printed grading scales for assessing the severity of contact lens-induced ocular pathology is to use computer-generated grading morphs. This technique involves manipulation of a continuously variable movie sequence until this matches the severity of the condition being observed. To validate the use of computer morphs, nine experienced optometrists were each invited to grade - to the nearest 0.1 increment - an image of each of 16 contact lens complications, using printed scales (Efron Grading Scales for Contact Lens Complications) and computer morphs (Efron Grading Morphs). This entire procedure was repeated approximately 2 weeks later, yielding a total data base comprising of 576 individual grading estimates. Good accuracy was achieved using computer morphs, as evidenced by the similarity between the mean of the test and retest grading estimates for the printed scales (2.8 +/- 0.7) and the computer morphs (2.6 +/- 0.8) (F1,8 = 2.7, p = 0.14). There was no difference in median reliability between the printed scales (+/- 0.41) and the computer morphs (+/- 0.43) (Z = 0.1, p = 0.95). Computer morphs are thus considered to have been validated in view of their accuracy and reliability compared with printed scales. In addition, computer morphs offer considerable utility in terms of computer-based clinical record keeping, teaching and learning, and clinical research.