Elsevier

Ophthalmology

Volume 110, Issue 6, June 2003, Pages 1110-1118
Ophthalmology

Tear function and ocular surface changes in keratoconus

Presented at the 30th Congress of the European Contact Lens Society of Ophthalmologists, Antalya, Turkey, September 2000; the 2001 Association for Research in Vision and Ophthalmology meeting, Fort Lauderdale, Florida, April 2001; and the 13th Congress of the European Society of Ophthalmology, Istanbul, Turkey, June 2001.
https://doi.org/10.1016/S0161-6420(03)00261-6Get rights and content

Abstract

Purpose

To describe the ocular surface disorder in patients with keratoconus.

Design

A prospective, case-controlled study.

Participants

Seventy-five eyes of 38 patients with keratoconus seen at Uludag University School of Medicine, Department of Ophthalmology, from March 2000 through April 2001, and 80 eyes of 40 normal control subjects were studied.

Intervention

The subjects underwent routine ophthalmic examinations, corneal sensitivity measurements, Schirmer test, tear film breakup time (BUT), fluorescein and rose bengal staining of the ocular surface, and conjunctival impression cytology.

Main outcome measures

Patients and control subjects were compared for corneal sensitivity, tear function, ocular surface staining parameters, goblet cell density, and squamous metaplasia grade. The relation of these parameters to the severity of keratoconus progression was also investigated.

Results

The mean corneal sensitivity was significantly lower in keratoconus patients compared with control subjects (P < 0.001). The BUT values were also significantly lower in the keratoconus group. Patients with keratoconus had significantly higher fluorescein and rose bengal staining scores (P < 0.001). Corneal sensitivity and tear function changes seemed to get worse with advanced stages of keratoconus. Impression cytology showed goblet cell loss and conjunctival squamous metaplasia, both of which again related to the extent of progression of keratoconus.

Conclusions

The ocular surface disease in keratoconus is characterized by disorder of tear quality, squamous metaplasia, and goblet cell loss, all of which seem to relate to the extent of keratoconus progression.

Section snippets

Subjects and examinations

Seventy-five eyes of 38 keratoconus patients (23 males and 16 females) aged between 12 and 46 years (mean, 24.8 years), as well as 80 eyes of 40 normal subjects aged from 12 to 47 years (mean, 24 years; 20 males and 20 females), were recruited from the Department of Ophthalmology of Uludag University Hospital from April 2000 through May 2001. Both groups were similar regarding age and sex characteristics. Routine ophthalmic examinations consisted of best-corrected visual acuity measurements,

Clinical features

There were no age- or sex-related statistical differences between patients with keratoconus and control subjects. The duration of patient-reported keratoconus eye disease varied from 1 to 24 years (mean, 8.0 ± 5.9 years). Thirty-one patients (81.5%) complained of symptoms of eye fatigue, irritation, and foreign-body sensation. Slit-lamp biomicroscopy of the eyelid margins and conjunctiva did not reveal any coexistent blepharitis, meibomian gland disorder, or conjunctivitis. However, 35 eyes

Discussion

Previous histopathologic and biochemical studies revealed numerous structural, metabolic, and functional abnormalities in the conjunctiva and cornea of patients with keratoconus. Recently, release of stromal collagen degradation products (telopeptides) into the tear film of keratoconus patients has also been reported.27 How these abnormalities affect the ocular surface and the tear functions in keratoconus still remains controversial. We thought that description of the tear film and ocular

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