Ocular surface changes in type II diabetic patients with proliferative diabetic retinopathy.
OBJECTIVE
To detect and analyze the changes on ocular surface and tear function in type II diabetic patients with proliferative diabetic retinopathy (PDR), an advanced stage of diabetic retinopathy (DR), using conventional ophthalmic tests and the high-resolution laser scanning confocal microscopy.


METHODS
Fifty-eight patients with type II diabetes were selected. Based on the diagnostic criteria and stage classification of DR, the patients were divided into the non-DR (NDR) group and the PDR group. Thirty-six patients with cataract but no other ocular and systemic disease were included as non-diabetic controls. All the patients were subjected to the conventional clinical tests of corneal sensitivity, Schirmer I Test, and corneal fluorescein staining. The non-invasive tear film break-up time (NIBUT) and tear interferometry were conducted by a Tearscope Plus. The morphology of corneal epithelia and nerve fibers was examined using the high-resolution confocal microscopy.


RESULTS
The NDR group exhibited significantly declined corneal sensitivity and Schirmer I test value, as compared to the non-diabetic controls (P< 0.001). The PDR group showed significantly reduced corneal sensitivity, Schirmer I test value, and NIBUT in comparison to the non-diabetic controls (P < 0.001). Corneal fluorescein staining revealed the progressively injured corneal epithelia in the PDR patients. Moreover, significant decrease in the corneal epithelial density and morphological abnormalities in the corneal epithelia and nerve fibers were also observed in the PDR patients.


CONCLUSIONS
Ocular surface changes, including blunted corneal sensitivity, reduced tear secretion, tear film dysfunction, progressive loss of corneal epithelia and degeneration of nerve fibers, are common in type II diabetic patients, particularly in the diabetic patients with PDR. The corneal sensitivity, fluorescein staining scores, and the density of corneal epithelial cells and nerve fibers in the diabetic patients correlate with the duration of diabetes. Therefore, ocular surface of the patients with PDR should be examined regularly by conventional approaches and confocal microscopy to facilitate early diagnosis and treatment of keratopathy.
Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
Yan
Y
Gao
College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin Medical University Eye Institute, Tianjin Medical University Eye Hospital, Tianjin 300384, China.
Yan
Y
Zhang
College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin Medical University Eye Institute, Tianjin Medical University Eye Hospital, Tianjin 300384, China.
Yu-Sha
YS
Ru
Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
Xiao-Wu
XW
Wang
Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
Ji-Zhong
JZ
Yang
Department of Ophthalmology, Shanxi Medical University First Hospital, Taiyuan 030001, Shanxi Province, China.
Chun-Hui
CH
Li
Department of Ophthalmology, Beijing Chuiyangliu Hospital Affiliated to Tsinghua University, Beijing 100022, China.
Hong-Xing
HX
Wang
College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin Medical University Eye Institute, Tianjin Medical University Eye Hospital, Tianjin 300384, China.
Xiao-Rong
XR
Li
Shanxi Eye Hospital, Taiyuan 030002, Shanxi Province, China.
Bing
B
Li
confocal microscopy; corneal sensitivity; ocular surface; proliferative diabetic retinopathy; tear film break-up time; type II diabetes