Our study describes, for what we believe to be the first time, common as well as rare ophthalmic findings derived from a very large-scale database of medical records of a large and randomized population. There are sparse reports on the prevalence of many of the described variables. All of the participants, who were ophthalmology patients, underwent comprehensive ophthalmic evaluations that included anterior segment and dilated fundus examinations, thus providing us with the rare opportunity to describe both common and rare ophthalmic conditions.
Adnexa
Dermatochalasis and blepharitis were the most common eyelid conditions, with a prevalence of 13% each, ranging from 0.5–4.5% in the 18–40-year age group, and up to 45% in the older groups. Although dermatochalasis is very common among the elderly, there are very few reports demonstrating its true prevalence. In contrast, the prevalence of blepharitis is well-described, and reportedly can be as common as 48–58% in patients 60 years of age or older.[3] Our population was less affected, most probably because patients tended to be younger. Of note, previous reports observed that the prevalence of Demodex blepharitis was higher among patients treated with anti-inflammatory medications for dry eye;[3] however, the disease is underdiagnosed and should be specifically screened in any ophthalmic assessment.
Blepharoptosis
The prevalence of ptosis in our cohort of patients was 1.8% overall and 10% in patients older than 80 years of age. Various population-based studies described similar numbers ranging from 4.7–13.5%, [4]–[7] demonstrating the widespread nature of ptosis among the elderly. Ptosis results in reduced visual field (VF) and tired appearance, as well as reduced independence, depression and anxiety, and reduced health-related quality of life.[8] VF loss is also associated with recurrent falls and a higher risk of hip and non-hip fractures.[9] Ptosis correction surgery is associated with a higher functional index and significant improvements in activities of daily living.[10]
Cataract
The anterior segment pathologies of cataract and pseudophakia were by far the most common, with an overall prevalence of 30.1%, from 1% in younger patients and rising to 94% in patients older than 80 years. This is similar to previous studies that described an average cataract prevalence of 17.2%, with most patients being older than 60 years.[11] We found a higher prevalence of both cataracts and pseudophakia among males, although other studies have shown that it may be more common in women.[12] A recent study investigated the current prevalence of pseudophakia in a well-defined united states population, and found a total prevalence of 6.5%, with the majority of patients older than 75 years being pseudophakic,[1] similar to our findings.
Retina
Age related macular degeneration (AMD) is a multifactorial disorder due to dysregulation of the lipid, complement, inflammatory, angiogenic, and extracellular matrix pathways, and is a leading cause of visual impairment and severe vision loss.[13] Macular drusen and retinal pigment epithelium (RPE) changes are two of the early signs of AMD. In the current study, RPE changes were observed in 12% and macular drusen in 3% of the ophthalmic patients, and, as expected, these rates increased with age from 1.8–57% and 0.3–24%, respectively. Alterations of the RPE are presumed to be important indicators of impaired RPE function.[14] Such RPE changes are an important sign of AMD, such that even minor changes in RPE (e.g., hypopigmentation or RPE elevation) are significant risk factors for progression to exudative AMD.[15] However, our findings demonstrated that RPE changes can also be observed in normal individuals and, importantly, the prevalence of RPE changes in healthy subjects has not been reported before. The prevalence of AMD generally ranges from 0.1–17.6%.[16] However, macular drusen can be a normal sign of aging, especially when they are not associated with RPE changes.[17] The incidence and prevalence of drusen subtypes are known to vary between populations.[18] Early diagnosis of RPE changes and the presence of macular drusen can indicate the need for a prompt ocular computerized tomographic )OCT( exam for AMD diagnosis, leading to the prevention of vision loss. These findings further emphasize the importance of a routine comprehensive ophthalmological evaluation that includes a dilated fundus examination.
Optic Nerve Head
Evaluation of the ONH and peripapillary architecture is an essential part of any ophthalmological assessment. The normal ONH varies from one person to another.[19] We observed that the ON had a tilted configuration in 9.2% of our ophthalmic patients, and was more common in females. Other studies described a range of ON tilting to be up to 0.09%-3.5%.[20] Our relatively high rate may be related to the increased incidence of myopia in our country’s population, which ranges from 30–80%, and higher in the ultra-orthodox population.[21] Moreover, the prevalence and progression of myopia are known to be associated with ethnicity.[22]
PPA is a common ocular finding, with 2 distinct zones of atrophy (alpha and beta) that can surround the optic disc.[23] Beta zone atrophy can be seen in glaucomatous as well as in non-pathological nerves, while alpha zone atrophy is more common in normal eyes, and is located beyond the beta zone away from the nerve head.[24] In addition, PPA is highly prevalent in eyes with geographic atrophy due to AMD, and is also associated with high myopia.[25] The overall prevalence of unspecified PPA in the current study was 13.5%, which is lower than that reported in other studies.[23], [24] The relation of PPA to glaucoma will be elaborated in a separate report.
Furthermore, some less common ON disorders were also observed in this study. MNFL is a rare, benign retinal finding that consists of whitish, well-demarcated patches on the outermost retinal surface that obscure the underlying retinal vessels.[26] It has been reported to occur in 0.57–1% of the general population, with a potential for growth in 10% of cases.[27] A prevalence of 0.3% was observed in this study.
Optic pit is a rare optic disc cavitary anomaly that is observed in about 1 in 11,000 of the general population.[28] It is typically congenital, unilateral, and occurs equally in males and females.[28] Interestingly, an optic pit was observed in 3 of the 36,762 ophthalmic patients in this study, a very similar prevalence to that described in studies starting as early as 1908.[29] It can be complicated with optic disc pit maculopathy and require surgical intervention.[30]
ON colobomas are rare congenital defects that have been reported to occur in about 0.25% of 12,000 patients examined ophthalmoscopically.[31] Colobomas are due to abnormal closure of the fetal fissure in the inferonasal quadrant of the developing optic cup, and have typical funduscopic appearances.[32] In the current study, ON colobomas were observed in 4 patients, suggesting a higher frequency of 1:9190 patients.
The prevalence of ONHD was 0.1%. It had been reported to be clinically identified in around 1% of patients, subclinical in around 2.4%, and bilateral in most cases.[33] It is typically an incidental asymptomatic finding, however, can rarely be associated with progressive VF loss, choroidal neovascularization, increased risk of non-arthritic ischemic optic neuropathy and vascular occlusion.[34]
Deep learning (DL)-based Artificial Intelligence (AI) has been widely used in general medicine as well as in ophthalmology.[35] It can also be used in telemedicine for diagnosing and monitoring eye diseases. In general, DL allows computer-based processing to learn representations with multiple layers of abstraction, and has dramatically improved image recognition and processing. DL in ophthalmology has been applied mainly in fundus photographs of diabetic retinopathy, AMD, retinopathy of prematurity, glaucoma, as well as oculoplastic surgery. DL enabled us to analyze the current large database and extract normal data.
Limitations of the current report may exist; for example, individuals attending the medical screening institute may not necessarily represent the general population in Israel, with a bias towards middle-aged and relatively high-income males, who routinely undergo periodic examinations.
In conclusion, normal values in medicine serve as reference points for all physical examinations and allow for early detection and monitoring of disease states. Here, for the first time, we present the prevalence of both common and rare ocular findings derived from a very large data set. The values provide reference points for the diagnosis of diseases and pathological states that comprise the essential elements of a comprehensive ophthalmic assessment.