In vivo confocal microscopy of conjunctiva in preservative-free timolol 0.1% gel formulation therapy for glaucoma.
PURPOSE
To evaluate the effects at 1 year of preservative-free timolol gel and preserved timolol eye drops on conjunctiva and tear parameters.


METHODS
Forty patients with primary open-angle glaucoma or ocular hypertension were randomized to the two treatment groups and compared with 20 healthy age-matched controls. Clinical tests (IOP, Schirmer I test, and lacrimal film break-up time BUT) and in vivo conjunctival confocal microscopy (IVCM) were performed in all patients at baseline and after 12 months. IVCM (HRT II Rostock Cornea Module; Heidelberg Engineering GmbH, Heidelberg, Germany) was performed after topical anaesthesia in the four cardinal locations and at the corresponding limbus to analyse conjunctiva cells. The main IVCM outcomes were goblet cell density and epithelial regularity.


RESULTS
IVCM and clinical parameters were similar in the three groups at baseline. After 12 months, intra-epithelial goblet cell density was significantly lower in the preserved (48.25 ± 7.70) than in the preservative-free beta-blocker group (86.83 ± 22.17, p < 0.001) and controls (88.9 ± 18.33, p < 0.001). The epithelial layer was significantly more regular in the preserved beta-blocker medication group than in the preservative-free beta-blocker group (p < 0.001) and the control group (p < 0.001). A significant reduction in both Schirmer I and BUT was found in the group of preserved timolol (respectively, 11.3 ± 2.97 and 8.12 ± 0.99) compared with preservative-free timolol (16.8 ± 1.83 and 11.27 ± 1.27, p < 0.001) and controls (17.8 ± 1.87 and 12.10 ± 1.28, p < 0.001).


CONCLUSIONS
Based on our IVCM data, preservative-free beta-blocker gel induces less changes at ocular surface than preserved beta-blockers, a fact that should be considered to obtain less adverse effects and maximal adherence to treatment in a chronic condition such as glaucoma.
['Frezzotti|Paolo|P|', 'Fogagnolo|Paolo|P|', 'Haka|Gentiana|G|', 'Motolese|Ilaria|I|', 'Iester|Michele|M|', 'Bagaglia|Simone A|SA|', 'Mittica|Pietro|P|', 'Menicacci|Cristina|C|', 'Rossetti|Luca|L|', 'Motolese|Eduardo|E|']
D000319:Adrenergic beta-Antagonists D001548:Benzalkonium Compounds D002452:Cell Count D003228:Conjunctiva D005260:Female D005782:Gels D005902:Glaucoma, Open-Angle D020397:Goblet Cells D006801:Humans D007429:Intraocular Pressure D008297:Male D018613:Microscopy, Confocal D008875:Middle Aged D009798:Ocular Hypertension D004364:Pharmaceutical Preparations D011310:Preservatives, Pharmaceutical D013666:Tears D013999:Timolol D014065:Tonometry, Ocular
in vivo confocal microscopy antiglaucoma drugs conjunctival modification toxicity