Relocating corneal endothelial area by non-contact specular microscopy

Tomoyuki Kunishige, M.D., Hisaharu Suzuki, M.D., Hideaki Oharazawa, M.D., Toshihiko Shiwa,M.D.,

Hiroshi Takahashi, M.D.

Authors have no finacial interest.

Nippon Medical School Hospital

Backgrounds

The corneal endothelial damages evaluated by specular microscopy are often considered to indicate invasiveness of cataract surgery.

However, the small area of the specular microscopy limits its reliability of analysis, because the microscopic field may not necessarily trace the same area in every examination.

Purpose

To examine whether the same corneal area can be located by non-contact specular microscopy in serial observations.

Methods

・ Subjects ：

・ Normal Volunteers: 15 eyes of 15 volunteers

mean age = 39 years, male : female = 4 : 11

・ Pseudophakic patients (1 month postop): 15 eyes of 15 patients mean age = 73 years, male : female = 9 : 6

・ Observation period ： April, 2009 ～ January, 2010

A non-contact specular microscope(noncon Robo CA, Konan Medical, Japan)

・ Analysis device

・ Evaluation time intervalsRepeated three times at 1-minute intervals and 1month later

・ Evaluation of fixation

Fixation status of all subjects, i.e. whether they could fix the target for 10 seconds, was confirmed by phoriascope before each examination.

・ Marker cells and confirmation of their relocation

An unique pattern of a cluster of cells was used as a marker. Whether the same pattern can be located in repeated examinations was assessed.

Results

In all subjects including normal volunteers and pseudophakic patients, the marker cells could be located in serial specular microscopic observations.

Representative photographs of a normal volunteer

The beginning 1 minute later 2 minutes later 1 month later

Representative photographs of a pseudophakic patient

The beginning 1 minute later 2 minutes later 1 month later

DiscussionReliable analysis of morphological alterations by non-contact specular microscopy should be based on the fact that the observation objects are the same. However, since the area of non-contact specular microscopy is small, it has not been clarified whether the usual examination by non-contact specular microscopy actually captures the same area or not. In this study, in subjects who can maintain their fixation at least 10 seconds, the same endothelial area can be located by non-contact specular microscopy in serial observations. The results suggest that usual examination by non-contact specular microscopy seems to be reliable enough in analyzing the morphological alterations in corneal endothelium.

Conclusions

The same corneal endothelial area can be located by non-contact specular microscopy in repeated examinations.