The effect of third eyelid gland removal on the ocular surface of dogs.


Saito A, Izumisawa Y, Yamashita K, Kotani T. The effect of third eyelid gland removal on the ocular surface of dogs. Vet Ophthalmol. 2001;4(1):13-18. / PMID: 11397314


To evaluate the effect of third eyelid removal on the ocular surface of dogs, we operated on five young Beagle dogs and observed changes to tear function using the following tests: phenol red thread test (PRT), Schirmer tear test (STT-1), modified Schirmer tear test (STT-2), pH and tear break-up time (BUT). There was a significant decrease (37%) in STT-2 within 2 weeks after the excision and this declined further to 60% at 1 year. The pH value increased after excision. Presurgical pH was 7.17 +/- 0.20 (mean +/- SD), which increased to 7.55 +/- 0.24 in the 14-60 days following removal, and further increased to 7.77 +/- 0.65 at 1 year. The PRT and STT-1 decreased by 26% within 3-7 months compared to pre-excision values, but by 1 year the values recovered to near normal. The BUT pre-excision value was 24.0 +/- 8.1 s, which shortened to 13.5 +/- 4.5 s after 5 months and continued to decrease further during the study. There were no overt visual signs of KCS during the observational period. However, microinjury of the keratoconjunctival epithelium was observed for all operated eyes when vital staining was used at 1 year post surgery. Surgical excision of the third eyelid in Beagle dogs influenced tear quality level and affected the stability of the tear layer, and at 1 year there was evidence of microinjury to the keratoconjunctival epithelium.
第三眼瞼切除における犬の眼表面への影響を評価するため5頭の若いビーグル犬に手術を行い、phenol red thread test(PRT)、Schirmer tear test(STT-1)、modified Schirmer tear test(STT-2)、pHおよびtear break-up time(BUT)等の検査を実施して涙機能の変化を観察した。摘出後2週間以内にSTT-2は明らかな低下(37%)が認められ、1年後では60%にまで低下した。切除後pH値は上昇した。手術前のpHは、7.17±0.24(平均±SID)であり、切除後14-60日では7.55±0.24まで上昇し、術後1年では7.77±0.65まで上昇した。PRTおよびSTT-1は切除前の値と比較して3-7ヶ月で26%減少したが、術後1年までにほとんど正常に回復した。BUTの切除前の値は、24.0±8.1秒であったが、5ヶ月後には13.5±4.5秒と短縮し、本研究中も短縮は続いていた。観察の期間中には、KCSの明らかな徴候は認められなかった。しかし術後1年後におこなった生体染色時に、手術をした全眼球の角結膜上皮の微小な傷が観察された。ビーグル犬に対する第三眼瞼の外科的切除は、涙液の質や涙液層の安定性に影響を及ぼし、術後1年後に角結膜上皮に微小な傷の存在が認められた。