13. DED Assessment II + Lacrimal I Flashcards
What are the 3 Es of meibomian gland evaluation?
- Evaluate lid margin
- Express glands
- Examine secretion colour and consistency
How are the meibomain glands expressed?
Using a meibomain gland evaluator. It helps squeeze across aroound 5 glands, mimicking forced blinking. 5 glands temporally and nasally should be evaluated for each eye.
What is the Meibomain Glands Yielding Liquid Secretion (MGS) score?
Evaluates and scores the meibomain gland secretion. 3 = clear liquid secretion, 2 = cloudy liquid secretion, 1 = inspissated/ toothpaste secretion, 0 = no secretion.
MGS score of 12 or less indicates clinically significant meibomain gland dysfunction.
What is tear interferometry?
Tear interferometry assess the tear lipid layer quantitatively and qualitatively. It looks at the reflected light patterns. It can estimate the thickness of tear lipid layer, where a normal layer should be 100nm thick. Abnormal values are between 70-80nm .
Meibography is an in vivo visualisation of ..., including the ... and .... The device utilises white light transillumination and ... illumination. Meibography can be used to quantify the .... Studies have found that inferior lid tend to .... MG thickness and tortuosity can be altered in ..., but less correlated to .... There is currently no ....
Meibography is an in vivo visualisation of meibomian gland morphology, including the ducts and acini. The device utilises white light transillumination and infra-red illumination. Meibography can be used to quantify the extent of meibomain gland dropout in % area of lid. Studies have found that inferior lid tend to have more dropout than superior lid in dry eyes. MG thickness and tortuosity can be altered in allergic conjunctivitis, but less correlated to dry eyes. There is currently no universally accepted grading scale.
What are the 3 components of the lacrimal system? Which structures are associated with each?
3 components: secretory, distribution and drainage. Secretory invovles the lacrimal gland, accessory glands of Krause and Wolfring;
Distribution involves the tear meniscus and blinking;
Drainage involves the puncta, lacrimal canaliculi, lacrimal sac and lacrimal duct.
The lacrimal gland is an ...-shaped, ...-lobed exocrine gland. It is composed of .... There are ... surronding the ductal and acinar cells, which help .... There are ... that open into the .... The lacrimal gland is responsible for secreting key tear components e.g. >>>. It is innervated by the ... for sensory and by the sympathetic nerve for autonomic responses.
The lacrimal gland is an almond-shaped, bi-lobed exocrine gland. It is composed of secretory epithelial cells. There are myoepithelial cells surronding the ductal and acinar cells, which help maintain gland shape. There are 12 tubular ducts that open into the fornix of superior eyelid. The lacrimal gland is responsible for secreting key tear components e.g. water, electrolytes, some proteins. It is innervated by the Ophthalmic division of the lacrimal nerve for sensory and by the sympathetic nerve for autonomic responses.
The accessory lacrmial glands are ... to the main lacrimal gland. Glands of ... is located in the stroma of the .... There are ... in the upper fornix, and ...in the lower fornix.Glands of... is located in the ... along the borders of the .... They are slightly ... in comparison. These accessory lacrimal glands make up ...% oof the total lacrimal secretory mass.
The accessory lacrmial glands are structurally and histologically similar to the main lacrimal gland. Glands of Krause is located in the stroma of the conjunctival fornix. There are 20-30 in the upper fornix, and 6-8 in the lower fornix. Glands of Wolfring is located in the conjunctiva along the borders of the inferior and superior tarsal plates. They are slightly larger and fewer in number in comparison. These accessory lacrimal glands make up 10% oof the total lacrimal secretory mass.
Meniscometry is an ... quantification of the .... It has a strong correlation with the ..., which is an non-invasive marker of ....
The normative value for tear mensicus height (TMH) is ...mm. This measures from the .... ... can be used to aid with measurements. Further research is required to fully understand the tole of pootnetial confounders, such as ... etc..
Meniscometry is an non-invasive quantification of the tear meniscus. It has a strong correlation with the Schirmer test, which is an non-invasive marker of aqueous deficiency. The normative value for tear mensicus height (TMH) is 0.20mm. This measures from the bottom of lid margin up to edge of pupil. Slit lamp and OCT can be used to aid with measurements. Further research is required to fully understand the tole of pootnetial confounders, such as age, gender ethnicity, eyelid anatomy etc..
Schirmer test is the most common technique to assess .... There are 2 types:
* ... which does not involve the use of ..., therefore measures ....
* ... uses ..., therefore only measures basal tears. This test uses a ... placed in the .... The wetting length is measured after ... minutes. This test, however, has poor ... and is relatively poor at ... for mild to moderate DED. Measurement of <...mm indicates aqeuous deficiency.
Schirmer test is the most common technique to assess aqueous production. There are 2 types: Schirmer I which does not involve the use of anaesthesia, therefore measures both basal and reflex tears. Schirmer II uses anaesthesia, therefore only measures basal tears. This test uses a calibrated sterile strip placed in the infero-temperal conjunctival sac. The wetting length is measured after 5 minutes. This test, however, has poor repeatability and is relatively poor at discriminating for mild to moderate DED. Measurement of <5mm indicates aqeuous deficiency.
Phenol red thread test uses a ..., ... sensitive thread of …mm in length. It is inserted into the ..., non-... ... for ... seconds. The ... is measured. It has very low .../ ... meaning that it can miss a lot of people with dry eyes. It does not appear to .... A measurement of <...mm is considered to correlate with dry eyes.
Phenol red thread test uses a fine, pH sensitive thread of 70mm in length. It is inserted into the temporal, non-anaethetised conjuncival sac for 15 seconds. The length of wetted thread is measured. It has very low sensitivity/ true positive rate meaning that it can miss a lot of people with dry eyes. It does not appear to correlate with tear volume measures using other techniques. A measurement of <10mm is considered to correlate with dry eyes.
What is the lid parallel conjunctival folds (LIPCOF)?
They are small folds in the bulbar conjunctiva that align parallel to the lid margin. They are thought to arise due to frictional interactions between the lid wiper and conjunctiva and can influence distribution of tears across the ocular surface. The presence of LIPCOF indicates that the lid wiper region should be investigated.
What is InflammaDry?
It is a non-specific test of ocular surface inflammation. It looks at the presence of MMP-9 protein which is thought to be associated with inflammation. Result is positive when there is >40ng/mL in tears.
How is blinking evaluated for dry eyes?
Under the slit lamp, patient’s blinking frequency is observed. Normal blinking rate should be around 10-15 per min. Incomplete blinking should also be observed.
What tool can be used to investigate incomplete blinking
Korb-Blackie transillumination test for lagophthalmos. If px has incomplete seal of eyelids, light will escape between the lids using the transilluminator while px closes their eyes.
