In clinic, many eye diseases are closely related to ocular refractive problems. Many problems of eye diseases will directly lead to ametropia or the change of refractive power. Therefore, optometrists need to be familiar with the refractive characteristics of relevant eye diseases, which can not only improve the accuracy of optometry, but also find relevant eye diseases from the optometry results, so as to reduce misdiagnosis and missed diagnosis. In this paper, the author will mainly introduce three common eye diseases that cause myopia, hyperopia and astigmatism.

1. Pterygium: Astigmatism

Pterygium is one of the common eye diseases. It is a kind of fibrous vascular tissue connected with conjunctiva growing to the corneal surface. It often occurs in the eyelid fissure area on the nasal side. Pterygium can cause obvious astigmatism. The main reason is that pterygium grows into the cornea, causing corneal compression and traction, corneal flattening and curvature change, resulting in hyperopia astigmatism. Some scholars also believe that the aggregation of tears in the corneal head leads to astigmatism.

It is generally believed that when the length of pterygium invading the cornea is 2.5mm ~ 3.5mm, it can cause obvious astigmatism. The closer the head of pterygium is to the center of cornea, the greater the impact on corneal refraction. In clinic, if large astigmatism is found in patients with pterygium, it is generally recommended to operate as soon as possible.

Therefore, the corresponding anterior segment examination should be done before optometry. Patients with pterygium ophthalmopathy should pay attention to the relationship between astigmatism and axial direction and pterygium morphology.

2. Nuclear Cataract: Myopia

Cataract can be divided into cortical, nuclear and posterior subcapsular cataract according to the location of lens opacity. Among them, nuclear cataract occurs earlier and progresses slowly. With the increase of age, the density of lens nucleus gradually increases. Due to the enhancement of nuclear refractive power, lens myopia occurs, and the far vision decreases slowly, but the near vision can be kept normal for a long time. After entering the old age, high myopia is often accompanied by nuclear cataract, and the degree of myopia increases further.

For the elderly, nuclear cataract leads to myopia. Reading newspapers and sewing are handy. Therefore, when prescribing glasses for such patients, we should fully consider the needs of near vision, so as not to obtain better far vision, but patients often complain about the difficulty of seeing near.

Slit lamp microscope showed lens nuclear opacity

Increased lens power in nuclear cataract

3. Central Serous Retinochoroidopathy: Hyperopia

In the optometry and glasses matching work, the author often encountered the patient's main complaint: Recently, the visual acuity of one eye decreased, and the myopia degree was found to be reduced by optometry, and the corrected visual acuity was normal. However, after the new prescription glasses were matched, although the corrected visual acuity was 1.0, it was still "invisible". In fact, this is likely to be the emergence of "central serous retinochoroidopathy".

The disease is mostly seen in young and middle-aged men (25 ~ 50 years old) in good health. It usually occurs in one or both eyes. It is usually a self limiting disease, but it can relapse. The pathogenesis is serous retinal pigment epithelium caused by increased permeability of choroidal capillaries (RPE) detachment, which further induces the destruction of RPE barrier function, leading to RPE leakage and posterior pole serous retinal detachment. Retinal uplift causes the shortening of intraocular axis, resulting in the hyperopia change of refractive state, that is, the decrease of mild hyperopia or original myopia.

The clinical manifestations were decreased visual acuity, darkened, deformed and smaller visual objects, accompanied by a relatively dark central area, a 1 ~ 3pd size, round or oval flat disc-shaped serous detachment area in the macular area of the fundus, and the reflection of the fovea disappeared.

Therefore, for young and middle-aged men, when the main complaint of vision loss (especially dim vision), slight hyperopia ametropia or slight decline in the original myopia degree are found during optometry, and the corrected vision is normal or close to normal, the fundus should be checked in detail to rule out the possibility of the disease.

Normal macula, foveal reflection visible

Round serous detachment area can be seen in macular area

Superficial macular retinal detachment

To sum up, optometrists should be familiar with the clinical characteristics of the above refractive related eye diseases. In optometry and glasses matching, for the newly appeared ametropia or the original ametropia degree changes greatly, they should consider the possibility of related eye diseases and refer them to the ophthalmic clinic in time to avoid misdiagnosis.