Deep Blue Dot Corneal Degeneration
Deep blue dot corneal degeneration is a very rare form of corneal degeneration observed in elderly individuals and characterized by bilateral, numerous extracellular blue opacities in the pre-Descemet's membrane. The diagnosis of this condition is primarily obtained and differentiated from similar corneal diseases via visual examination using biomicroscopy and confocal microscopy. Also, the exact etiology and pathophysiology of this corneal disease remains unknown and there is no treatment. Although this condition is largely asymptomatic, blurry vision has been reported as well as potential surgical complications.
Deep Blue Dot Corneal Degeneration ICD-10-H18.40
Deep blue dot corneal degeneration is a rare form of corneal degeneration observed in elderly individuals and characterized by bilateral, numerous extracellular blue opacities between the corneal stroma and Descemet’s membrane.  
Deep blue dot corneal degeneration has been classified as a degenerative disease and has been observed to affect elderly individuals. More broadly, corneal degeneration encompasses corneal aberrations that can be caused by advancing age, medications, disease, trauma, infection, or environmental factors, so any combination or presence of these factors may play a role in its etiology.
Older age is thought to be the primary risk factor for this condition.  Given the lack of reported cases and research on this condition, it is unknown if or how genetics might influence or cause its development.
The stromal deposits in this corneal degeneration have been histologically proven to consist of amyloid.  These deposits are numerous extracellular, hyper-reflective, often bilateral, and diffusely and evenly spread discrete blue oval opacities at the level of deep corneal stroma (at an approximate stromal depth of 430-480 microns). One case report also identified fine, hyper-reflective, extracellular gray linear needle-like opacities at the level of mid-to-deep corneal stroma (at an approximate stromal depth of 330-370 microns), suggesting two types of hyper-reflective extracellular opacities that may be found in the pathology this entity. The corneal endothelium remains intact and normal. These findings have also been described as limited to the central two-thirds of the cornea.
Though the exact pathophysiological mechanisms are currently unknown, older age and subsequently decreased efficiency of certain biological processes may result in the formation of the characteristic blue amyloid deposits.  Furthermore, although mainly asymptomatic, these amyloid deposits, especially when present in greater density in the middle and deep corneal stroma, may result in inflammatory responses leading to subepithelial fibrosis of corneal stroma and Bowman’s membrane causing corneal haze and loss of visual acuity due to the strong refractive quality of this corneal layer. 
The diagnosis of deep blue dot corneal degeneration is primarily obtained and differentiated from similar corneal diseases via visual examination using biomicroscopy and confocal microscopy. Though not clinical, affected corneal stroma may also be biopsied and studied histologically.
Deep blue dot corneal degeneration will often be found incidentally in elderly individuals since it does not usually cause visual impairment. However, blurry vision has been reported in one patient.
Slit-lamp microscopy is the first step in the diagnosis of corneal disease. However, confocal microscopy has been observed as a valuable instrument in differentiating between this and other similar corneal entities. 
Other than what can be found on biomicroscopy, no other signs have been reported.
Other than blurry vision documented in one study, no other symptoms have been reported.
Biomicroscopy is required to detect the distinct pattern and presentation of deep blue dot corneal degeneration and to differentiate it from other potential diagnoses also characterized by opacities in the corneal stroma.   Confocal microscopy has also been especially sensitive in detecting various hyperreflective particles and shapes at various depths of the corneal stroma in a patient affected by this condition. Additionally, corneal stroma could be biopsied and studied histologically to see if the opacities present are amyloid.
There are currently no laboratory tests for diagnosing this condition.
- Cornea farinata
- Fleck corneal dystrophy (FCD; Francois-Neetens corneal dystrophy)
- Pre-Descemet corneal dystrophy (PDCD)
- Epithelial basement membrane corneal dystrophy (EBMCD; Cogan microcystic corneal dystrophy)
Although mainly asymptomatic, blurry vision and surgical complications have been reported in patients with deep blue dot corneal degeneration. Therefore, patients should be followed to monitor extent of stromal involvement and to assess risks associated with specific surgical procedures.
There is no treatment for deep blue dot corneal degeneration.
Patients who exhibit significant stromal involvement may require glasses to correct for astigmatism.
Medical follow up
Regular visits to an eye care provider are recommended to assess stromal involvement and subsequent refractive abnormalities such as astigmatism
Surgical follow up
No official recommendations for surgical follow-up have been given besides the regular follow up required after corneal transplantation.
Deep blue dot corneal degeneration has been reported as a predisposing factor to Descemet membrane detachment during or following phacoemulsification or deep lamellar keratoplasty (DALK). Consequently, it may be wise to perform a thorough slit-lamp examination and microscopy on elderly patients prior to performing either of these surgical procedures.
- Moshirfar M, Bennett P, Ronquillo Y. Corneal Dystrophy. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557865/.
- Mandal S, Sahay P, Nagpal R, Maharana PK. Deep blue dot corneal degeneration: a rare corneal degeneration. BMJ Case Reports CP. 2022;15(4):e248458. doi:10.1136/BCR-2021-248458
- AlRajhi AA. Descemet Membrane Detachment Secondary to Deep Blue Dot Degeneration. American Academy of Ophthalmology. Published January 10, 2014. Accessed May 17, 2022. https://www.aao.org/annual-meeting-video/descemets-membrane-detachment-secondary-to-deep-bl
- Selvan H, Singh A, Tandon R. Deep blue dot corneal degeneration: confocal characteristics. International Ophthalmology. 2019;39(3):667-669. doi:10.1007/S10792-018-0849-7/FIGURES/3
- Moshirfar M, Bennett P, Ronquillo Y. Corneal Dystrophy. StatPearls. Published online August 11, 2021. Accessed May 18, 2022. https://www.ncbi.nlm.nih.gov/books/NBK557865/
- Miller DD, Hasan SA, Simmons NL, Stewart MW. Recurrent corneal erosion: a comprehensive review. Clinical Ophthalmology (Auckland, NZ). 2019;13:325. doi:10.2147/OPTH.S157430
- Sridhar MS. Anatomy of cornea and ocular surface. Indian Journal of Ophthalmology. 2018;66(2):190. doi:10.4103/IJO.IJO_646_17
- Lanza M, Borrelli M, Benusiglio E, Rosa N. In vivo confocal microscopy of an apparent deep stroma corneal dystrophy: a case report. Published online 2009. doi:10.1186/1757-1626-2-9317
- Birkholz ES, Syed NA, Wagoner MD. Epithelial-Stromal and Stromal Corneal Dystrophies. The University of Iowa. Published August 17, 2009. Accessed May 18, 2022. https://webeye.ophth.uiowa.edu/eyeforum/cases/43-corneal-stromal-dystrophies.htm
- Weiss JS, Møller HU, Lisch W, et al. The IC3D Classification of the Corneal Dystrophies. Published online 2008. doi:10.1097/ICO.0b013e31817780fb
- Klintworth GK. Corneal dystrophies. Orphanet Journal of Rare Diseases. 2009;4(1):1-38. doi:10.1186/1750-1172-4-7/FIGURES/54
- Møller HU, Sunde L. Prevalence of Corneal Dystrophies in the United States: Estimates from Claims Data. Investigative Ophthalmology & Visual Science. 2013;54(1):387-387. doi:10.1167/IOVS.12-11211
- Musch DC, Niziol LM, Stein JD, Kamyar RM, Sugar A. Prevalence of Corneal Dystrophies in the United States: Estimates from Claims Data. Investigative Ophthalmology & Visual Science. 2011;52(9):6959-6963. doi:10.1167/IOVS.11-7771