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At the Ocular Surface Center, Dr. Tseng employs a number of special diagnostic tests to sort out the causes of Dry Eye, and identify dysfunctional elements causing Ocular Surface Failure.

  • Fluorescein Clearance Test (FCT) [Click here for more details]
    A dynamic tear functional test to reveal basic tearing, reflex tearing and tear clearance simultaneously
  • Kinetic Analysis of Tear Interference Images [Click here for more details]
    A new test (US Patent filed) to reveal the dynamic spread of lipid layer on the tear film during blinking
  • Differential Dye Staining [Click here for more details]
    Differential uses of fluorescein and rose Bengal dyes allow dissecting the complexity of different ocular surface diseases
  • Impression Cytology [Click here for more details]
    The Impression Cytology Laboratory of the Ocular Surface Center is the first in USA that has been certified by the State of Florida (No. 800017632) and CLIA (Clinical Laboratory Improvement Amendment 1998) (No. 10D1004176) for diagnosing ocular surface failure in patients suffering difficult ocular surface diseases.
  • Kinetic Measurement of Tear Evaporation Rate
    The tear evaporation rate as well as the skin evaporation rate can be measured in a real time manner for patients showing tear film abnormalities and skin abnormalities.
  • Microscopic Sampling of Lashes for Demodex Infestation
    This test can help diagnose the underlying etiology of patients suffering from blepharitis and meibomian gland dysfunction.

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Fluorescein Clearance Test

A dynamic tear functional test to reveal basic tearing, reflex tearing and tear clearance simultaneously

How to do? See Fig. 5
How to interpret? See Fig. 6, Fig. 7, Fig. 8

Fig. 5 (click to enlarge)
Fig. 7 (click to enlarge)
Fig. 6 (click to enlarge)
Fig. 8 (click to enlarge)

Clinical Uses

  • To determine aqueous tear deficiency (dry eye) with higher accuracy with respect to basic and reflex tearing
  • To differentiate dry eye into with or without reflex tearing. Sjogren syndrome or primary lacrimal gland diseases are characterized by the loss of reflex tearing, thus helping establish the severity of dry eye
  • To guide punctal occlusion to be performed with plugs or permanent cauterization
  • To determine if punctal occlusion is performed with proficiency
  • To determine subclinical delayed tear clearance as a cause of ocular irritation, medicamentosa and other ocular surface disorders, and help direct more effective treatments such as non-preserved methylprednisolone

    For more details, download PDF

Relevant Literature

  • Prabhasawat P, Tseng SCG. Frequent association of delayed tear clearance in ocular irritation. Br J Ophthalmol 82:666-675, 1998.
  • Afonso AA, Sobrin L, Monroy DC, et al. Tear fluid gelatinase B activity correlates with IL-1a concentration and fluorescein clearance in ocular rosacea. Invest Ophthalmol Vis Sci 1999;40:2506-12.
  • Afonso AA, Monroy D, Stern ME, et al. Correlation of tear fluorescein clearance and Schirmer test scores with ocular irritation symptoms. Ophthalmology 1999;106:803-10.
  • Macri A, Pflugfelder SC. Correlation of the Schirmer 1 and fluorescein clearance tests with the severity of corneal epithelial and eyelid disease. Arch Ophthalmol 2000;118:1632-8.

If you would like to receive a reprint of the article in pdf file listed above, please contact Dr. Tseng at stseng@ocularsurface.com by stating which Article or simply copy the entire citation.

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Kinetic Analysis of Tear Interference Images

A new test (US Patent filed) to reveal the dynamic spread of lipid layer on the tear film during blinking

How to do? See Fig. 9
How to interpret? See Fig. 10

Fig. 9 (click to enlarge)
Fig. 10 (click to enlarge)

Clinical Uses

  • To differentiate lipid tear deficiency and aqueous tear deficiency in dry eye patients
  • To determine the cause of dry eye following LASIK
  • To demonstrate the blink-related microtrauma due to the friction between the lids and eye surface
  • To direct specific treatment using lipid supplement therapies

    For more details, download PDF

Relevant Literature

  • Goto E, Tseng SCG. Differentiation of lipid tear deficiency dry eye by kinetic analysis of tear interference images . Arch Ophthalmol 121:173-180, 2003.
  • Goto E, Tseng SCG. Kinetic analysis of tear interference images in aqueous tear deficiency dry eye before and after punctal occlusion . Invest Ophthalmol Vis Sci 44:1897-1905, 2003.
  • Di Pascuale M, Goto E, Tseng SCG. Changes of lipid tear film in dry eye patients and normal subjects following one drop of a new emulsion eye drop using kinetic analysis of tear interference images. Ophthalmology 111:783-791, 2004.
  • Di Pascuale MA, Liu T-S, Trattler W, Tseng SCG. Lipid tear deficiency in persistent dry eye after LASIK and treatment results of a new eye warming device. Ophthalmology, submitted, 2004.

If you would like to receive a reprint of the article in pdf file listed above, please contact Dr. Tseng at stseng@ocularsurface.com by stating which Article or simply copy the entire citation.

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Differential Dye Staining

Differential uses of fluorescein and rose Bengal dyes allow dissecting to different ocular surface diseases

How to interpret? See Fig. 11

Fig. 11 (click to enlarge)

Clinical Uses

  • To differentiate primary neurotrophic from secondary neurotrophic effect (See Fig. 12)
  • To correlate squamous metaplasia with rose Bengal staining (See Fig. 13)
  • To suggest limbal stem cell deficiency by late-fluorescein staining (See Fig. 14, upper panel)
  • To differentiate CIN recurrence from limbal stem cell deficiency (Fig. 14, lower panel)
  • To differentiate neurotrophic ulcer from persistent epithelial defect caused by limbal stem cell deficiency (See Fig. 15)
  • To better visualize the obliteration of tear meniscus by conjunctivochalasis (redundant conjunctival folds), especially with the aid of Rattan Filter (Kodak) (see Fig. 47)
Fig. 12 (click to enlarge)
Fig. 14 (click to enlarge)
Fig. 47 (click to enlarge)
Fig. 13 (click to enlarge)
Fig. 15 (click to enlarge)

Relevant Literature

  • Feenstra RPG, Tseng SCG. What is actually stained by rose bengal? Arch Ophthalmol 110:984-993,1992.
  • Feenstra RPG, Tseng SCG. Comparison of fluorescein and rose bengal staining. Ophthalmology 99:605-617,1992.
  • Chodosh J, Dix R, Howell RC, Stroop WG, Tseng SCG. Staining characteristics and antiviral activity of sulforhodamine B and lissamine green B. Invest Ophthalmol Vis Sci 35:1046-1058, 1994.
  • Tseng SCG, Zhang S-H. Interaction between rose bengal and different tear components. Cornea 14:427-435, 1995.
  • Di Pascuale M, Espana EM, Kawakita T, Tseng SCG. Clinical characteristics of dry eye caused by conjunctivochalasis with or without aqueous tear deficiency. Br J Ophthalmol 88:388-392, 2004.

If you would like to receive a reprint of the article in pdf file listed above, please contact Dr. Tseng at stseng@ocularsurface.com by stating which Article or simply copy the entire citation.

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Impression Cytology

The Impression Cytology Laboratory of the Ocular Surface Center is the first in USA that has been certified by the State of Florida (No. 800017632) and CLIA (Clinical Laboratory Improvement Amendment 1998) (No. 10D1004176) for diagnosing ocular surface failure in patients suffering difficult ocular surface diseases.

How to order Impression Cytology Test from Ocular Surface Center?

An Impression Cytology kit can be sent to the physician who is interested in using this test for patients with ocular surface failure

To order such a test, please contact Dr. Tseng at
Ocular Surface Center,
7000 SW 97th Avenue, Suite 213,
Miami, FL 33173
Tel: (305) 274-1299 Fax: (305) 274-1297 Cellular: (305) 803-6925
E-mail: stseng@ocularsurface.com

Click here to download General Information for Ordering Impression Cytology [PDF file]

How to perform Impression Cytology?


Clinical Uses

  • To diagnose definitely limbal stem cell deficiency [See Fig. 16] by demonstrating the presence of "conjunctivalization" of the cornea
  • It is important to determine if limbal stem cell deficiency is present [See Fig. 17]. LSCD is contraindicated for corneal transplantation (PKP) because transplant will fail.
  • To differentiate Squamous Metaplasia from Limbal Stem Cell Deficiency [See Fig. 18]. In these three patients, only the left one has LSCD and the other two have Squamous Metaplasia although they look similarly.
Fig. 16 (click to enlarge)
Fig. 18 (click to enlarge)
Fig. 17 (click to enlarge)

Relevant Literature

  • Tseng SCG. Staging of conjunctival squamous metaplasia by impression cytology. Ophthalmology 92:728-733, 1985.
  • Wittpenn JR, Tseng SCG, Sommer A. Detection of early xerophthalmia by impression cytology. Arch Ophthalmol 104:237-239, 1986.
  • Puangsricharen V, Tseng SCG. Cytologic evidence of corneal diseases with limbal stem cell deficiency. Ophthalmology 102:1476-1485, 1995.

If you would like to receive a reprint of the article in pdf file listed above, please contact Dr. Tseng at stseng@ocularsurface.com by stating which Article or simply copy the entire citation.

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