Preparation and clinical evaluation of succinylated collagen punctal plugs in dry eye syndrome: a pilot study.

AIM: This is a pilot study of 10 eyes of 6 patients. This paper describes the preparation and clinical evaluation of succinylated collagen punctal plugs (SCPP) in the treatment of dry eye syndrome (DES). METHODS: SCPP were prepared from succinylated collagen with the exact dimensions of the punctum (length 1.5-2.5 mm, diameter 0.2-0.5 mm, water content between 50 and 55%). All the patients were clinically evaluated for best corrected visual acuity (BCVA), tear fluid levels (TFL), protein content, tear fluid osmolarity (TFO), fluorescence staining of the cornea and tear break-up time (TBUT) before and after punctal occlusion with SCPP. RESULTS: TFL improved among all the patients after punctal occlusion with SCPP. BCVA showed improvement in case 4 (right eye/left eye), case 5 (left eye) and case 6 (right eye), who had developed dry eyes due to environmental conditions. Protein content increased on day 7 in all the patients and gradually decreased. TFO decreased on days 3 and 5 in all patients after punctal occlusion with SCPP, and showed the same levels on day 14. TFL, PC, TFO and TBUT showed significant improvement in all the patients after punctal occlusion with SCPP. CONCLUSION: All patients experienced symptomatic relief after punctal occlusion with SCPP. There was no discomfort, foreign body sensation, plug extrusion, corneal aberration, infection, or formation of pyogenic granuloma with SCPP. SCPP stands as a promising alternative to other punctal plugs in the treatment of DES.

Evaluation of succinylated collagen bandage lenses in corneal healing by the expression of matrix metalloproteinases (MMP-2 and MMP-9) in tear fluid.

AIM: The aim of the study was to evaluate the efficacy of succinylated collagen bandage lenses (SCBL) in the healing of various corneal conditions. METHODS: Clinical evaluation of SCBL was carried out in patients with corneal ulcer (CU), recurrent corneal erosions (RCE), dry eyes (DE) and corneal lesion (CL). In each patient, corneal healing was studied by subjective clinical assessment such as pain, redness, watering, discomfort, irritation, foreign body sensation, biochemical analysis of tear fluid (TF) for protein content, expression of matrix metalloproteinases (MMPs) by gelatin zymography (GZ) and Western blotting (WB). In both GZ and WB bands were quantified and analyzed by gel documentation analyzer. RESULTS: Subjective clinical assessment of CU, RCE, DE and CL patients after treatment with SCBL showed significant reduction in the symptoms, patients felt comfortable with SCBL with no change in visual acuity, indicating complete transparency of SCBL. Protein content was very high on day 1 among all the patients, and it reduced gradually after treatment with SCBL signifying corneal healing. GZ of TF showed the expression of both MMP-2 and MMP-9 on day 3. There was significant reduction in MMP-2 and MMP-9 expression on day 7 in all cases, it decreased considerably on day 14 and was almost negligible on day 21 reflecting corneal healing with SCBL. CONCLUSION: Our study indicated that SCBL significantly reduces symptoms of irritation and discomfort in the cornea. It maintains visual acuity, controls inflammation and watering in the eye reflecting corneal healing in all cases studied by us. SCBL represents a promising alternative to other bandage lenses in corneal healing.

Clinical evaluation of succinylated collagen bandage lenses for ophthalmic applications.

AIM: To study whether succinylated collagen bandage lenses (SCBL) prepared from modified bovine collagen (succinylated collagen) can replace other bandage lenses presently employed to treat various corneal conditions like filamentary keratitis, dry eyes, recurrent corneal erosions, foreign body removal and epithelial trauma. METHODS: This observational case study included 32 patients (22 female and 10 male): 8 patients for filamentary keratitis (25%), 10 patients for dry eyes (31%), 4 patients for recurrent corneal erosions (13%), 7 patients for foreign body removal (22%) and 3 patients for epithelial trauma (9%). Their eyes were evaluated for biocompatibility, in vivo transparency, patient comfort, corneal fit, best corrected visual acuity (BCVA), tear fluid level and dissolution rate of SCBL. This was carried out over a 24-hour period of time. RESULTS: SCBL exhibited good transparency and remained transparent throughout the period of study (between 0 and 24 h) in the eyes of patients. SCBL did not cause any irritation, discomfort and foreign body sensation in the eye and eyes remained comfortable throughout the experiment. BCVA in the control group of patients was 1.00 (20/20). Mean (+/-SD) BCVA before inserting SCBL (in decimal equivalent) was 0.31 (20/60) +/- 0.18 (range 0.1- 0.66). BCVA (+/-SD) changed to 0.25 (20/80) +/- 0.18 4 h after the application of SCBL and 0.27 (20/70) +/- 0.18 24 h after the application of SCBL, with a safety index of 1.20. The mean (+/-SD) tear fluid level before application of SCBL was 11.9 +/- 5.39 h (range 3-24 mm) and changed to 13.9 +/- 5.68 h (range 5-28 mm) after 4 h of application of SCBL and 15.9 +/- 5.72 h (range 7-30 mm) after 24 h with a safety index of 13 mm. The mean (+/-SD) dissolution rate of SCBL in the control group of patients was 17.8 +/- 8.65 h (range 10-24 h) and the mean (+/-SD) dissolution rate in the experimental group was 22.2 +/- 9.29 h (range 10-24 h). We report the use of SCBL in various corneal conditions. CONCLUSION: The present study showed that SCBL has complete corneal fit and good comfort in human eyes. Transparency was maintained for a longer period along with fair visual acuity and improvement in tear fluid levels. The disadvantages of other bandage lenses presently used to treat various corneal conditions could be overcome by the use of SCBL lenses.

A novel method to measure oxygen permeability and transmissibility of contact lenses.

PURPOSE: The present paper describes an accurate and cost-effective method requiring simple equipment to measure the oxygen permeability and transmissibility of contact lenses. METHOD: The method involves accurate measurement of oxygen across the material by allowing the gas (oxygen) to pass through the lens material in a specially fabricated lens mould. The expelled gas is collected by dissolution in ethanol and the oxygen is measured by titration of the solvent. RESULT: This method is suitable for the measurement of oxygen permeability and transmissibility of contact lenses of varying thickness and different radii of curvature. It can measure Dk and Dk/t of collagen bandage lenses in both wet and dry conditions. CONCLUSION: The oxygen permeability and transmissibility values obtained by this method were compared with the oxygen permeability standard values of commercially available contact lenses and the results are summarised.